
<PAGE>

                                                                     EXHIBIT 4.1



                                  ONEOK, INC.

                                    Issuer


                                      and



                                 [__________]


                                    Trustee



                         JUNIOR SUBORDINATED INDENTURE


                        Dated as of [__________], 1999
<PAGE>

                                  ONEOK, INC.

     Reconciliation and tie between the Trust Indenture Act of 1939, as amended
(the "Trust Indenture Act") (including cross-references to provisions of
Sections 310 to and including 317 which, pursuant to Section 318(c) of the Trust
Indenture Act are a part of and govern the Junior Subordinated Indenture dated
as of [__________], 1999 (the "Junior Subordinated Indenture") whether or not
physically contained therein), and the Junior Subordinated Indenture.


              Trust Indenture
                Act Section                    Indenture Section

(S) 310 (a)(1), (2) and (5).................  6.9
(a) (3).....................................  Not Applicable
(a)(4)......................................  Not Applicable
(b).........................................  6.8
                                              6.10
(S) 311 (a).................................  6.13
(b).........................................  6.13
(b) (2).....................................  7.3(a)
(c).........................................  Not Applicable

(S) 312 (a).................................  7.1
                                              7.2(a)
(b).........................................  7.2(b)
(c).........................................  7.2(c)
(S) 313 (a).................................  7.3(a)
(b).........................................  7.3(a), (b)
(c).........................................  7.3(a), 7.3(b)
(d).........................................  7.3(c)
(S) 314 (a)(1), (2) and (3).................  7.4
(a)(4)......................................  10.5
(b).........................................  Not Applicable
(c)(1)......................................  1.2
(c)(2)......................................  1.2
(c)(3)......................................  Not Applicable
(d).........................................  Not Applicable
(e).........................................  1.2
(f).........................................  Not Applicable
(S) 315 (a).................................  6.1(a)
(b).........................................  6.2
                                              7.3(a), (b)
(c).........................................  6.1(b)
(d).........................................  6.1(c)
(d)(1)......................................  6.1(a)(1)
(d)(2)......................................  6.1(c)(2)
(d)(3)......................................  6.1(c)(3)
(e).........................................  5.14

<PAGE>

              Trust Indenture
                Act Section                       Indenture Section

(S) 316  (a)................................. 1.1
(a)(1)(A).................................... 5.12
(a)(1)(B).................................... 5.13
(a)(2)....................................... Not Applicable
(b).......................................... 5.8
(c).......................................... 1.4(f)
(S) 317  (a)(1).............................. 5.3
(a)(2)....................................... 5.4
(b).......................................... 10.3
(S) 318  (a)................................. 1.7


          [Note:  This reconciliation and tie is not and shall not, for any
          purpose, be deemed to be a part of the Junior Subordinated Indenture.]

<PAGE>


                               TABLE OF CONTENTS
                               -----------------

<TABLE>
<CAPTION>
<S>                                                                                                                    <C>
ARTICLE I   DEFINITIONS AND OTHER PROVISIONS
             OF GENERAL APPLICATION..................................................................................   1

            Section 1.1    Definitions...............................................................................   1
            Section 1.2    Compliance Certificate and Opinions.......................................................   9
            Section 1.3    Forms of Documents Delivered to Trustee...................................................   9
            Section 1.4    Acts of Holders...........................................................................  10
            Section 1.5    Notices, Etc. to the Trustee and the Company..............................................  12
            Section 1.6    Notice to Holders; Waiver.................................................................  12
            Section 1.7    Conflict with Trust Indenture Act.........................................................  12
            Section 1.8    Effect of Headings and Table of Contents..................................................  13
            Section 1.9    Successors and Assigns....................................................................  13
            Section 1.10   Separability Clause.......................................................................  13
            Section 1.11   Benefits of Indenture.....................................................................  13
            Section 1.12   Governing Law.............................................................................  13
            Section 1.13   Non-Business Days.........................................................................  13

ARTICLE II  SECURITY FORMS...........................................................................................  14

            Section 2.1    Forms Generally...........................................................................  14
            Section 2.2    Form of Face of Security..................................................................  14
            Section 2.3    Form of Reverse of Security...............................................................  17
            Section 2.4    Additional Provisions Required in Global Security.........................................  20
            Section 2.5    Form of Trustee's Certificate of Authentication...........................................  20

ARTICLE III THE SECURITIES...........................................................................................  20

            Section 3.1    Title and Terms...........................................................................  20
            Section 3.2    Denominations.............................................................................  23
            Section 3.3    Execution, Authentication, Delivery and Dating............................................  23
            Section 3.4    Temporary Securities......................................................................  24
            Section 3.5    Registration, Transfer and Exchange.......................................................  25
            Section 3.6    Mutilated, Destroyed, Lost and Stolen Securities..........................................  26
            Section 3.7    Payment of Interest; Interest Rights Preserved............................................  27
            Section 3.8    Persons Deemed Owners.....................................................................  28
            Section 3.9    Cancellation..............................................................................  28
            Section 3.10   Computation of Interest...................................................................  29
            Section 3.11   Deferrals of Interest Payment Dates.......................................................  29
            Section 3.12   Right of Set-Off..........................................................................  30
            Section 3.13   Agreed Tax Treatment......................................................................  30
            Section 3.14   Shortening or Extension of Stated Maturity................................................  30
            Section 3.15   CUSIP Numbers.............................................................................  30

ARTICLE IV  SATISFACTION AND DISCHARGE...............................................................................  31
</TABLE>
<PAGE>

<TABLE>
<S>                                                                                                                    <C>
            Section 4.1    Satisfaction and Discharge of Indenture..................................................   31
            Section 4.2    Application of Trust Money...............................................................   32
            Section 4.3    Satisfaction, Discharge and Defeasance of Securities of Any Series.......................   32

ARTICLE V   REMEDIES................................................................................................   34

            Section 5.1    Events of Default........................................................................   34
            Section 5.2    Acceleration of Maturity; Rescission and Annulment.......................................   35
            Section 5.3    Collection of Indebtedness and Suits for
                           Enforcement by Trustee...................................................................   36
            Section 5.4    Trustee May File Proofs of Claim.........................................................   36
            Section 5.5    Trustee May Enforce Claim Without Possession of Securities...............................   37
            Section 5.6    Application of Money Collected...........................................................   37
            Section 5.7    Limitation on Suits......................................................................   38
            Section 5.8    Unconditional Right of Holders to Receive Principal,
                           Premium and Interest; Direct Action by Holders
                           of Preferred Securities..................................................................   38
            Section 5.9    Restoration of Rights and Remedies.......................................................   39
            Section 5.10   Rights and Remedies Cumulative...........................................................   39
            Section 5.11   Delay or Omission Not Waiver.............................................................   39
            Section 5.12   Control by Holders.......................................................................   39
            Section 5.13   Waiver of Past Defaults..................................................................   40
            Section 5.14   Undertaking for Costs....................................................................   40
            Section 5.15   Waiver of Usury, Stay or Extension Laws..................................................   41

ARTICLE VI  THE TRUSTEE.............................................................................................   41

            Section 6.1    Certain Duties and Responsibilities......................................................   41
            Section 6.2    Notice of Defaults.......................................................................   42
            Section 6.3    Certain Rights of Trustee................................................................   42
            Section 6.4    Not Responsible for Recitals or Issuance of Securities...................................   43
            Section 6.5    May Hold Securities......................................................................   43
            Section 6.6    Money Held in Trust......................................................................   43
            Section 6.7    Compensation and Reimbursement...........................................................   44
            Section 6.8    Disqualification; Conflicting Interests..................................................   44
            Section 6.9    Corporate Trustee Required; Eligibility..................................................   44
            Section 6.10   Resignation and Removal; Appointment of Successor........................................   45
            Section 6.11   Acceptance of Appointment by Successor...................................................   46
            Section 6.12   Merger, Conversion, Consolidation or Succession to Business..............................   47
            Section 6.13   Preferential Collection of Claims Against Company........................................   47
            Section 6.14   Appointment of Authenticating Agent......................................................   48

ARTICLE VII HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY.......................................................   49

            Section 7.1    Company to Furnish Trustee Names
                           and Addresses of Holders.................................................................   49
</TABLE>

                                     -ii-
<PAGE>

<TABLE>
<S>                                                                                                                   <C>
            Section 7.2    Preservation of Information, Communications to Holders....................................  49
            Section 7.3    Reports by Trustee........................................................................  50
            Section 7.4    Reports by the Company....................................................................  50

ARTICLE VIII  CONSOLIDATION, MERGER, CONVEYANCE,
               TRANSFER OR LEASE.....................................................................................  50

            Section 8.1    Company May Consolidate, Etc., Only on Certain Terms......................................  50
            Section 8.2    Successor Corporation Substituted.........................................................  51

ARTICLE IX  SUPPLEMENTAL INDENTURES..................................................................................  52

            Section 9.1    Supplemental Indentures without Consent of Holders........................................  52
            Section 9.2    Supplemental Indentures with Consent of Holders...........................................  53
            Section 9.3    Execution of Supplemental Indentures......................................................  54
            Section 9.4    Effect of Supplemental Indentures.........................................................  54
            Section 9.5    Conformity with Trust Indenture Act.......................................................  54
            Section 9.6    Reference in Securities to Supplemental Indentures........................................  55

ARTICLE X   COVENANTS................................................................................................  55

            Section 10.1   Payment of Principal, Premium and Interest................................................  55
            Section 10.2   Maintenance of Office or Agency...........................................................  55
            Section 10.3   Money or Security Payments to be Held in Trust............................................  56
            Section 10.4   Statement as to Compliance................................................................  57
            Section 10.5   Waiver of Certain Covenants...............................................................  57
            Section 10.6   Additional Sums...........................................................................  57
            Section 10.7   Additional Covenants......................................................................  58

ARTICLE XI  REDEMPTION OF SECURITIES.................................................................................  59

            Section 11.1   Applicability of This Article.............................................................  59
            Section 11.2   Election to Redeem; Notice to Trustee.....................................................  59
            Section 11.3   Selection of Securities to be Redeemed....................................................  59
            Section 11.4   Notice of Redemption......................................................................  60
            Section 11.5   Deposit of Redemption Price...............................................................  60
            Section 11.6   Payment of Securities Called for Redemption...............................................  60
            Section 11.7   Right of Redemption of Securities
                            Initially Issued to a ONEOK Capital Trust................................................  61

ARTICLE XII SINKING FUNDS............................................................................................  61

            Section 12.1   Applicability of Article..................................................................  61
            Section 12.2   Satisfaction of Sinking Fund Payments with Securities.....................................  62
            Section 12.3   Redemption of Securities for Sinking Fund.................................................  62

ARTICLE XIII SUBORDINATION OF SECURITIES.............................................................................  64
</TABLE>

                                     -iii-
<PAGE>

<TABLE>
          <S>                                                                                                        <C>
          Section 13.1   Securities Subordinate to Senior Debt.....................................................  64
          Section 13.2   Payment Over of Proceeds Upon Dissolution, Etc............................................  64
          Section 13.3   Prior Payment to Senior Debt Upon
                         Acceleration of Securities................................................................  65
          Section 13.4   No Payment When Senior Debt in Default....................................................  65
          Section 13.5   Payment Permitted If No Default...........................................................  66
          Section 13.6   Subrogation to Rights of Holders of Senior Debt...........................................  66
          Section 13.7   Provisions Solely to Define Relative Rights...............................................  67
          Section 13.8   Trustee to Effectuate Subordination.......................................................  67
          Section 13.9   No Waiver of Subordination Provisions.....................................................  67
          Section 13.10  Notice to Trustee.........................................................................  68
          Section 13.11  Reliance on Judicial Order or Certificate of
                         Liquidating Agent.........................................................................  68
          Section 13.12  Trustee Not Fiduciary for Holders of Senior Debt..........................................  69
          Section 13.13  Rights of Trustee as Holder of Senior Debt;
                         Preservation of Trustee 's Rights.........................................................  69
          Section 13.14  Article Applicable to Paying Agents.......................................................  69
          Section 13.15  Certain Conversions or Exchanges Deemed Payment...........................................  69
</TABLE>

                                     -iv-
<PAGE>

     JUNIOR SUBORDINATED INDENTURE dated as of [__________], 1999 (this
"Indenture") among ONEOK, INC., an Oklahoma corporation (the "Company") having
its principal office at 100 West Fifth Street, Tulsa, Oklahoma 74103, and
[__________], a national banking association duly organized and existing under
the laws of the United States, as Trustee (hereinafter called the "Trustee").


                            RECITALS OF THE COMPANY

     The Company has duly authorized the execution and delivery of this
Indenture (i) to provide for the issuance from time to time of its unsecured
junior subordinated notes in series (the "Securities") of substantially the
tenor hereinafter provided, including, without limitation, Securities issued to
evidence loans made to the Company of the proceeds from the issuance from time
to time by one or more business trusts (each, a "ONEOK Capital Trust" and,
collectively, the "ONEOK Capital Trusts") of preferred trust interests in such
ONEOK Capital Trusts (the "Preferred Securities") and common interests in such
ONEOK Capital Trusts (the "Common Securities" and, collectively with the
Preferred Securities, the "Trust Securities"), and (ii) to provide the terms and
conditions upon which the Securities are to be authenticated, issued and
delivered.

     All things necessary to make the Securities, when executed by the Company,
authenticated and delivered hereunder and duly issued by the Company, the valid
obligations of the Company, and to make this Indenture a valid agreement of the
Company, in accordance with their and its terms, have been done.

     NOW THEREFORE, THIS INDENTURE WITNESSETH:  For and in consideration of the
premises and the purchase of the Securities by the Holders thereof, it is
mutually covenanted and agreed, for the equal and proportionate benefit of all
Holders of Securities of any series thereof, as follows:


                                   ARTICLE I

     DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION

     Section 1.1  Definitions.

     For all purposes of this Indenture (and any indenture supplemental hereto),
except as otherwise expressly provided or unless the context otherwise requires:

          (1)  The terms defined in this Article have the meanings assigned to
them in this Article and include the plural as well as the singular;

          (2)  All other terms used herein which are defined in the Trust
Indenture Act, either directly or by reference therein, have the meanings
assigned to them therein;

          (3)  All accounting terms not otherwise defined herein or in the Trust
Indenture Act, either directly or by reference therein, have the meanings
assigned to them in accordance with
<PAGE>

generally accepted accounting principles, and the term "generally accepted
accounting principles" with respect to any computation required or permitted
hereunder shall mean such accounting principles which are generally accepted at
the date or time of such computation; provided, that when two or more principles
are so generally accepted, it shall mean that set of principles consistent with
those in use by the Company; and

          (4)  The words "herein," "hereof" and "hereunder" and other words of
similar import refer to this Indenture as a whole and not to any particular
Article, Section or other subdivision.

     "Act," when used with respect to any Holder, has the meaning specified in
Section 1.4 hereof.

     "Additional Interest" means the interest, if any, that shall accrue on any
interest on the Securities of any series the payment of which has not been made
on the applicable Interest Payment Date and which shall accrue at the rate per
annum specified or determined as specified in such Security.

     "Additional Sums" has the meaning specified in Section 10.6.

     "Additional Taxes" means the sum of any additional taxes, duties and other
governmental charges to which a ONEOK Capital Trust has become subject from time
to time as a result of a Tax Event.

     "Administrative Trustee" means, in respect of any ONEOK Capital Trust, each
Person identified as an "Administrative Trustee" in the related Trust Agreement,
solely in such Person's capacity as Administrative Trustee of such ONEOK Capital
Trust under such Trust Agreement and not in such Person's individual capacity,
or any successor administrative trustee appointed as therein provided.

     "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person; provided, however, no ONEOK Capital Trust to
                                    --------  -------
which Securities have been issued shall be deemed to be an Affiliate of the
Company.  For the purposes of this definition, "control" when used with respect
to any specified Person means the power to direct the management and policies of
such Person, directly or indirectly, whether through the ownership of voting
securities, by contract or otherwise; and the terms "controlling" and
"controlled" have meanings correlative to the foregoing.

     "Allocable Amounts," when used with respect to any Senior Debt, means all
amounts due or to become due on such Senior Debt less, if applicable, any amount
which would have been paid to, and retained by, the holders of such Senior Debt
(whether as a result of the receipt of payments by the holders of such Senior
Debt from the Company or any other obligor thereon or from any holders of, or
trustee in respect of, other indebtedness that is subordinate and junior in
right of payment to such Senior Debt pursuant to any provision of such
indebtedness for the payment over of amounts received on account of such
indebtedness to the holders of such Senior Debt or otherwise) but for the fact
that such Senior Debt is subordinate or junior in right of payment to (or
subject to a requirement that amounts received on such Senior Debt be paid over
to obligees on) trade accounts payable or accrued liabilities arising in the
ordinary course of business.

                                       2
<PAGE>

     "Authenticating Agent" means any Person authorized by the Trustee pursuant
to Section 6.14 to act on behalf of the Trustee to authenticate Securities of
one or more series.

     "Board of Directors" means either the board of directors of the Company or
any committee of that board duly authorized to act hereunder.

     "Board Resolution" means a copy of a resolution certified by the Secretary
or an Assistant Secretary of the Company to have been duly adopted by the Board
of Directors, or such committee of the Board of Directors or officers of the
Company to which authority to act on behalf of the Board of Directors has been
delegated, and to be in full force and effect on the date of such certification,
and delivered to the Trustee.

     "Business Day" means any day other than (i) a Saturday or Sunday, (ii) a
day on which banking institutions in The City of New York are authorized or
required by law or executive order to remain closed or (iii) a day on which the
Corporate Trust Office of the Trustee or, with respect to the Securities of a
series initially issued to a ONEOK Capital Trust, the principal office of the
Property Trustee under the related Trust Agreement, is closed for business.

     "Commission" means the Securities and Exchange Commission, as from time to
time constituted, created under the Exchange Act, or, if at any time after the
execution of this instrument such Commission is not existing and performing the
duties now assigned to it under the Trust Indenture Act, then the body
performing such duties on such date.

     "Common Securities" has the meaning specified in the first recital of this
Indenture.

     "Common Stock" means the common stock, without par value, of the Company.

     "Company" means the Person named as the "Company" in the first paragraph of
this Indenture until a successor corporation shall have become such pursuant to
the applicable provisions of this Indenture, and thereafter "Company" shall mean
any such successor corporation.

     "Company Request" and "Company Order" mean, respectively, the written
request or order signed in the name of the Company by the Chairman of the Board
of Directors, the Vice Chairman of the Board of Directors, its President or a
Vice President, and by its Treasurer, an Assistant Treasurer, its Secretary or
an Assistant Secretary, and delivered to the Trustee.

     "Corporate Trust Office" means the principal corporate trust office of the
Trustee at which, at any particular time, its corporate trust business shall be
administered, which office at the date hereof is located at [__________], except
for purposes of Section 10.2, if required with respect to a series of
Securities, such term shall mean the office or agency of the Trustee in the
Borough of Manhattan, The City of New York, which office at the date hereof is
located at [__________].

     "Corporation" includes a corporation, association, company, joint-stock
company or business trust.

     "Debt" means, with respect to any Person, whether recourse is to all or a
portion of the assets of such Person and whether or not contingent, (i) every
obligation of such Person for money

                                       3
<PAGE>

borrowed; (ii) every obligation of such Person evidenced by bonds, debentures,
notes or other similar instruments, including obligations incurred in connection
with the acquisition of property, assets or businesses; (iii) every
reimbursement obligation of such Person with respect to letters of credit,
bankers' acceptances or similar facilities issued for the account of such
Person; (iv) every obligation of such Person issued or assumed as the deferred
purchase price of property or services (but excluding trade accounts payable or
accrued liabilities arising in the ordinary course of business); (v) every
capital lease obligation of such Person; (vi) all indebtedness of such Person,
whether incurred on or prior to the date of this Indenture or thereafter
incurred, for claims in respect of derivative products, including interest rate,
foreign exchange rate and commodity forward contracts, options and swaps and
similar arrangements; and (vii) every obligation of the type referred to in
clauses (i) through (vi) of another Person and all dividends and operating lease
payments of another Person the payment of which, in either case, such Person has
guaranteed or is responsible or liable for, directly or indirectly, as obligor
or otherwise.

     "Defaulted Interest" has the meaning specified in Section 3.7.

     "Depositary" means, with respect to the Securities of any series issuable
or issued in whole or in part in the form of one or more Global Securities, the
Person designated as Depositary by the Company pursuant to Section 3.1 with
respect to such series (or any successor to the Depositary).

     "Discount Security" means any security which provides for an amount less
than the principal amount thereof to be due and payable upon a declaration of
acceleration of the Maturity thereof pursuant to Section 5.2.

     "Distributions," with respect to the Trust Securities issued by a ONEOK
Capital Trust, means amounts payable in respect of such Trust Securities as
provided in the related Trust Agreement and referred to therein as
"Distributions."

     "Dollar" means the currency of the United States of America that, at the
time of payment, is legal tender for the payment of public and private debts.

     "Event of Default," unless otherwise specified in the supplemental
indenture or Officers' Certificate creating a series of Securities, has the
meaning specified in Article V.

     "Exchange Act" means the Securities Exchange Act of 1934 and any statute
successor thereto, in each case as amended from time to time.

     "Expiration Date" has the meaning specified in Section 1.4.

     "Extension Period" has the meaning specified in Section 3.11.

     "Global Security" means a Security in the form prescribed in Section 2.4
evidencing all or part of a series of Securities, issued to the Depositary or
its nominee for such series, and registered in the name of such Depositary or
its nominee.

                                       4
<PAGE>

     "Guarantee Agreement" means the Guarantee Agreement between the Company and
the trustee certified therein, substantially in such form as may be specified as
contemplated by Section 3.1 with respect to the Securities of any series, in
each case as amended from time to time.

     "Holder" means a Person in whose name a Security is registered in the
Securities Register.

     "Indenture" means this instrument as originally executed or as it may from
time to time be supplemented or amended by one or more indentures supplemental
hereto entered into pursuant to the applicable provisions hereof and shall
include the terms of each particular series of Securities established as
contemplated by Section 3.1.

     "Interest Payment Date" means, as to each series of Securities, the Stated
Maturity of an installment of interest on such Securities.

     "Investment Company Act Event" means that a ONEOK Capital Trust shall have
received an Opinion of Counsel (as defined in the relevant Trust Agreement)
experienced in such matters to the effect that, as a result of the occurrence of
a change in law or regulation or a written change in the interpretation or
application of law or regulation by any legislative body, court, governmental
agency or regulatory authority, there is more than an insubstantial risk that
such ONEOK Capital Trust is or will be considered an "investment company" that
is required to be registered under the Investment Company Act of 1940, as
amended, which change becomes effective on or after the date of issuance of the
Preferred Securities of such ONEOK Capital Trust.

     "Junior Subordinated Payment" has the meaning specified in Section 13.2.

     "Maturity," when used with respect to any Security, means the date on which
the principal of such Security becomes due and payable as therein or herein
provided, whether at the Stated Maturity or by declaration of acceleration, call
for redemption or otherwise.

     "Moody's" means Moody's Investors Service, Inc.

     "Notice of Default" means a written notice of the kind specified in Section
5.1(3).

     "Officers' Certificate" means a certificate signed by the Chairman of the
Board of Directors, a Vice Chairman of the Board of Directors, the President or
a Vice President, and by the Treasurer, an Assistant Treasurer, the Secretary or
an Assistant Secretary of the Company, and delivered to the Trustee.

     "ONEOK Capital Guarantee" means the guarantee by the Company of
distributions on the Preferred Securities of a ONEOK Capital Trust to the extent
provided in the applicable Guarantee Agreement.

     "ONEOK Capital Trust" has the meaning specified in the first recital of
this Indenture.

     "Opinion of Counsel" means a written opinion of counsel, who may be counsel
for the Company and who shall be acceptable to the Trustee.

                                       5
<PAGE>

     "Original Issue Date" means the date of issuance specified as such in each
Security.

     "Outstanding" means, when used in reference to any Securities, as of the
date of determination, all Securities theretofore authenticated and delivered
under this Indenture, except:

     (i)       Securities theretofore canceled by the Trustee or delivered to
the Trustee for cancellation;

     (ii)      Securities for whose payment money in the necessary amount has
been theretofore deposited with the Trustee or any Paying Agent in trust for the
Holders of such Securities; and

     (ii)      Securities in substitution for or in lieu of which other
Securities have been authenticated and delivered or which have been paid
pursuant to Section 3.6, unless proof satisfactory to the Trustee is presented
that any such Securities are held by Holders in whose hands such Securities are
valid, binding and legal obligations of the Company; provided, however, that in
determining whether the Holders of the requisite principal amount of Outstanding
Securities have given any request, demand, authorization, direction, notice,
consent or waiver hereunder, Securities owned by the Company or any other
obligor upon the Securities or any Affiliate of the Company or such other
obligor shall be disregarded and deemed not to be Outstanding, except that, in
determining whether the Trustee shall be protected in relying upon any such
request, demand, authorization, direction, notice, consent or waiver, only
Securities which the Trustee knows to be so owned shall be so disregarded.
Securities so owned which have been pledged in good faith may be regarded as
Outstanding if the pledgee establishes to the satisfaction of the Trustee the
pledgee's right so to act with respect to such Securities and that the pledgee
is not the Company or any other obligor upon the Securities or any Affiliate of
the Company or such other obligor. Upon the written request of the Trustee, the
Company shall furnish to the Trustee promptly an Officers' Certificate listing
and identifying all Securities, if any, known by the Company to be owned or held
by or for the account of the Company, or any other obligor on the Securities or
any Affiliate of the Company or such obligor, and, subject to the provisions of
Section 6.1, the Trustee shall be entitled to accept such Officers' Certificate
as conclusive evidence of the facts therein set forth and of the fact that all
Securities not listed therein are Outstanding for the purpose of any such
determination.

     "Paying Agent" means the Trustee or any Person authorized by the Company to
pay the principal of or interest on any Securities on behalf of the Company.

     "Person" means any individual, corporation, partnership, joint venture,
trust, unincorporated organization or government or any agency or political
subdivision thereof.

     "Place of Payment" means, with respect to the Securities of any series, the
place or places where the principal of (and premium, if any) and interest on the
Securities of such series are payable pursuant to Sections 3.1 and 3.11.

     "Predecessor Security" of any particular Security means every previous
Security evidencing all or a portion of the same debt as that evidenced by such
particular Security; and, for the purposes of this definition, any security
authenticated and delivered under Section 3.6 in lieu of a lost, destroyed or
stolen Security shall be deemed to evidence the same debt as the lost, destroyed
or stolen Security.

                                       6
<PAGE>

     "Preferred Securities" has the meaning specified in the first recital of
this Indenture.

     "Proceeding" has the meaning specified in Section 13.2.

     "Property Trustee" means, in respect of any ONEOK Capital Trust, the
commercial bank or trust company identified as the "Property Trustee" in the
related Trust Agreement, solely in its capacity as Property Trustee of such
ONEOK Capital Trust under such Trust Agreement and not in its individual
capacity, or its successor in interest in such capacity, or any successor
property trustee appointed as therein provided.

     "Redemption Date," when used with respect to any Security to be redeemed,
means the date fixed for such redemption by or pursuant to this Indenture.

     "Redemption Price," when used with respect to any Security to be redeemed,
means the price at which it is to be redeemed pursuant to this Indenture.

     "Regular Record Date" for the interest payable on any Interest Payment Date
with respect to the Securities of a series means, unless otherwise provided
pursuant to Section 3.1 with respect to Securities of a series, (i) in the case
of Securities of a series represented by one or more Global Securities, the
Business Day next preceding such Interest Payment Date and (ii) in the case of
Securities of a series not represented by one or more Global Securities, the
date which is fifteen days next preceding such Interest Payment Date (whether or
not a Business Day).

     "Responsible Officer," when used with respect to the Trustee, means any
officer of the Trustee assigned by the Trustee from time to time to administer
its corporate trust matters or any other officer to whom such a matter may be
referred.

     "Rights Plan" means a plan of the Company providing for the issuance by the
Company to all holders of its Common Stock of rights entitling the holders
thereof to subscribe for or purchase shares of Common Stock or any class or
series of preferred stock, which rights (i) are deemed to be transferred with
such shares of Common Stock, (ii) are not exercisable and (iii) are also issued
in respect of future issuances of Common Stock, in each case until the
occurrence of a specified event or events.

     "S&P" means Standard & Poor's Ratings Services, a division of The McGraw-
Hill Companies, Inc.

     "Securities" or "Security" means any debt securities or debt security, as
the case may be, authenticated and delivered under this Indenture.

     "Securities Register" and "Securities Registrar" have the respective
meanings specified in Section 3.5.

     "Senior Debt" means the principal of (and premium, if any) and interest, if
any (including interest accruing on or after the filing of any petition in
bankruptcy or for reorganization relating to the Company, whether or not such
claim for post-petition interest is allowed in such proceeding), on Debt of the
Company, whether incurred on or prior to the date of this Indenture or
thereafter

                                       7
<PAGE>

incurred, unless, in the instrument creating or evidencing the same or pursuant
to which the same is outstanding, it is provided that such obligations are not
superior in right of payment to the Securities or to other Debt which is pari
passu with, or subordinated to, the Securities, provided, however, that Senior
Debt shall not be deemed to include (a) any Debt of the Company which, when
incurred and without respect to any election under Section 1111(b) of the
Bankruptcy Reform Act of 1978, was without recourse to the Company, (b) any Debt
of the Company, to any of its Subsidiaries, (c) Debt to any employee of the
Company and (d) any Securities.

     "Special Event" means an Investment Company Act Event or a Tax Event.

     "Special Record Date" for the payment of any Defaulted Interest means a
date fixed by the Trustee pursuant to Section 3.7.

     "Stated Maturity" when used with respect to any Security or any installment
of principal thereof or interest thereon means the date specified pursuant to
the terms of such Security as the date on which the principal of such Security
or such installment of interest is due and payable, in the case of such
principal, as such date may be shortened or extended as provided pursuant to the
terms of such Security and this Indenture.

     "Subsidiary" means, with respect to any Person, a corporation more than 50%
of the outstanding voting stock of which is owned, directly or indirectly, by
such Person or by one or more other Subsidiaries, or by such Person and one or
more other Subsidiaries.  For purposes of this definition, "voting stock" means
stock which ordinarily has voting power for the election of directors, whether
at all times or only so long as no senior class of stock has such voting power
by reason of any contingency.

     "Tax Event" means the receipt by a ONEOK Capital Trust of an Opinion of
Counsel (as defined in the relevant Trust Agreement) experienced in such matters
to the effect that, as a result of any amendment to, or change (including any
announced prospective change) in, the laws (or any regulations thereunder) of
the United States or any political subdivision or taxing authority thereof or
therein, or as a result of any official administrative pronouncement or judicial
decision interpreting or applying such laws or regulations, which amendment or
change is effective or which pronouncement or decision is announced on or after
the date of issuance of the Preferred Securities of such ONEOK Capital Trust,
there is more than an insubstantial risk that (i) such ONEOK Capital Trust is,
or will be within 90 days of the date of such Opinion of Counsel, subject to
United States federal income tax with respect to income received or accrued on
the corresponding series of Securities issued by the Company to such ONEOK
Capital Trust, (ii) interest payable by the Company on such corresponding series
of Securities is not, or within 90 days of the date of such Opinion of Counsel,
will not be, deductible by the Company, in whole or in part, for United States
federal income tax purposes or (iii) such ONEOK Capital Trust is, or will be
within 90 days of the date of such Opinion of Counsel, subject to more than a de
minimis amount of other taxes, duties or other governmental charges.

     "Trust Agreement" means the Trust Agreement, as amended by the form of
Amended and Restated Trust Agreement, substantially in such form as may be
specified as contemplated by Section 3.1 with respect to the Securities of any
series, in each case as amended from time to time.

                                       8
<PAGE>

     "Trustee" means the Person named as the "Trustee" in the first paragraph of
this instrument until a successor Trustee shall have become such pursuant to the
applicable provisions of this Indenture, and thereafter "Trustee" shall mean or
include each Person who is then a Trustee hereunder and, if at any time there is
more than one such Person, "Trustee," as used with respect to the Securities of
any series, shall mean the Trustee with respect to Securities of that series.

     "Trust Indenture Act" means the Trust Indenture Act of 1939, as amended and
as in effect on the date of this Indenture, except as provided in Section 9.5.

     "Trust Securities" has the meaning specified in the first recital of this
Indenture.

     "Vice President," when used with respect to the Company or the Trustee, as
the case may be, means any duly appointed vice president, whether or not
designated by a number or a word or words added before or after the title "Vice
President."

     Section 1.2    Compliance Certificate and Opinions.

     Upon any application or request by the Company to the Trustee to take any
action under any provision of this Indenture, the Company shall furnish to the
Trustee an Officers' Certificate stating that all conditions precedent
(including covenants compliance with which constitutes a condition precedent),
if any, provided for in this Indenture relating to the proposed action have been
complied with and an Opinion of Counsel stating that in the opinion of such
counsel all such conditions precedent (including covenants compliance with which
constitutes a condition precedent), if any, have been complied with, except that
in the case of any such application or request as to which the furnishing of
such documents is specifically required by any provision of this Indenture
relating to such particular application or request, no additional certificate or
opinion need be furnished.

     Every certificate or opinion with respect to compliance with a condition or
covenant provided for in this Indenture (other than the certificates provided
pursuant to Section 10.5) shall include:

     (1)   a statement that each individual signing such certificate or
opinion has read such covenant or condition and the definitions herein relating
thereto;

     (2)   a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

     (3)   a statement that, in the opinion of each such individual, he has made
such examination or investigation as is necessary to enable him to express an
informed opinion as to whether or not such covenant or condition has been
complied with; and

     (4)   a statement as to whether, in the opinion of each such individual,
such condition or covenant has been complied with.

     Section 1.3    Forms of Documents Delivered to Trustee.

     In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion

                                       9
<PAGE>

of, only one such Person, or that they be so certified or covered by only one
document, but one such Person may certify or give an opinion with respect to
some matters and one or more other such Persons may certify or give an opinion
as to other matters, and any such Person may certify or give an opinion as to
such matters in one or several documents.

     Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer knows, or in the exercise of
reasonable care should know, that the certificate or opinion or representations
with respect to matters upon which his certificate or opinion is based are
erroneous. Any such certificate or Opinion of Counsel may be based, insofar as
it relates to factual matters, upon a certificate or opinion of, or
representations by, an officer or officers of the Company stating that the
information with respect to such factual matters is in the possession of the
Company, unless such counsel knows, or in the exercise of reasonable care should
know, that the certificate or opinion or representations with respect to such
matters are erroneous.

     Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.

     Section 1.4    Acts of Holders.

     (a)   Any request, demand, authorization, direction, notice, consent,
waiver or other action provided by this Indenture to be given to or taken by
Holders may be embodied in and evidenced by one or more instruments of
substantially similar tenor signed by such Holders in person or by an agent duly
appointed in writing; and, except as herein otherwise expressly provided, such
action shall become effective when such instrument or instruments is or are
delivered to the Trustee, and, where it is hereby expressly required, to the
Company. Such instrument or instruments (and the action embodied therein and
evidenced thereby) are herein sometimes referred to as the "Act" of the Holders
signing such instrument or instruments. Proof of execution of any such
instrument or of a writing appointing any such agent shall be sufficient for any
purpose of this Indenture and (subject to Section 6.1) conclusive in favor of
the Trustee and the Company, if made in the manner provided in this Section.

     (b)   The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by the certificate of any notary public or other officer authorized
by law to take acknowledgments of deeds, certifying that the individual signing
such instrument or writing acknowledged to him the execution thereof. Where such
execution is by a Person acting in other than his individual capacity, such
certificate or affidavit shall also constitute sufficient proof of this
authority.

     (c)   The fact and date of the execution by any Person of any such
instrument or writing, or the authority of the Person executing the same, may
also be proved in any other manner which the Trustee deems sufficient and in
accordance with such reasonable rules as the Trustee may determine.

     (d)   The ownership of Securities shall be proved by the Securities
Register.

                                       10
<PAGE>

     (e)  Any request, demand, authorization, direction, notice, consent, waiver
or other action by the Holder of any Security shall bind every future Holder of
the same Security and the Holder of every Security issued upon the transfer
thereof or in exchange therefor or in lieu thereof in respect of anything done
or suffered to be done by the Trustee or the Company in reliance thereon,
whether or not notation of such action is made upon such Security.

     (f)  The Company may set any day as a record date for the purpose of
determining the Holders of Outstanding Securities of any series entitled to
give, make or take any request, demand, authorization, direction, notice,
consent, waiver or other action provided or permitted by this Indenture to be
given, made or taken by Holders of Securities of such series, provided that the
Company may not set a record date for, and the provisions of this paragraph
shall not apply with respect to, the giving or making of any notice,
declaration, request or direction referred to in the next paragraph. If any
record date is set pursuant to this paragraph, the Holders of Outstanding
Securities of the relevant series on such record date, and no other Holders,
shall be entitled to take the relevant action, whether or not such Holders
remain Holders after such record date, provided that no such action shall be
effective hereunder unless taken on or prior to the applicable Expiration Date
by Holders of the requisite principal amount of Outstanding Securities of such
series on such record date. Nothing in this paragraph shall be construed to
prevent the Company from setting a new record date for any action for which a
record date has previously been set pursuant to this paragraph (whereupon the
record date previously set shall automatically and with no action by any Person
be canceled and of no effect), and nothing in this paragraph shall be construed
to render ineffective any action taken by Holders of the requisite principal
amount of Outstanding Securities of the relevant series on the date such action
is taken. Promptly after any record date is set pursuant to this paragraph, the
Company, at its own expense, shall cause notice of such record date, the
proposed action by Holders and the applicable Expiration Date to be given to the
Trustee in writing and to each Holder of Securities of the relevant series in
the manner set forth in Section 1.6.

     The Trustee may set any day as a record date for the purpose of determining
the Holders of Outstanding Securities of any series entitled to join in the
giving or making of (i) any Notice of Default, (ii) any declaration of
acceleration referred to in Section 5.2, (iii) any request to institute
proceedings referred to in Section 5.7(2) or (iv) any direction referred to in
Section 5.12, in each case with respect to Securities of such series. If any
record date is set pursuant to this paragraph, the Holders of Outstanding
Securities of such series on such record date, and no other Holders, shall be
entitled to join in such notice, declaration, request or direction, whether or
not such Holders remain Holders after such record date, provided that no such
action shall be effective hereunder unless taken on or prior to the applicable
Expiration Date by Holders of the requisite principal amount of Outstanding
Securities of such series on such record date. Nothing in this paragraph shall
be construed to prevent the Trustee from setting a new record date for any
action for which a record date has previously been set pursuant to this
paragraph (whereupon the record date previously set shall automatically and with
no action by any Person be canceled and of no effect), and nothing in this
paragraph shall be construed to render ineffective any action taken by Holders
of the requisite principal amount of Outstanding Securities of the relevant
series on the date such action is taken. Promptly after any record date is set
pursuant to this paragraph, the Trustee, at the Company's expense, shall cause
notice of such record date, the proposed action by Holders and the applicable
Expiration Date to be given to the Company in writing and to each Holder of
Securities of the relevant series in the manner set forth in Section 1.6.

                                       11
<PAGE>

     With respect to any record date set pursuant to this Section, the party
hereto which sets such record date may designate any day as the "Expiration
Date" and from time to time may change the Expiration Date to any earlier or
later day, provided that no such change shall be effective unless notice of the
proposed new Expiration Date is given to the other party hereto in writing, and
to each Holder of Securities of the relevant series in the manner set forth in
Section 10.6, on or prior to the existing Expiration Date. If an Expiration Date
is not designated with respect to any record date set pursuant to this Section,
the party hereto which set such record date shall be deemed to have initially
designated the 180th day after such record date as the Expiration Date with
respect thereto, subject to its right to change the Expiration Date as provided
in this paragraph. Notwithstanding the foregoing, no Expiration Date shall be
later than the 180th day after the applicable record date.

     (g)  Without limiting the foregoing, a Holder entitled hereunder to take
any action hereunder with regard to any particular Security may do so with
regard to all or any part of the principal amount of such Security or by one or
more duly appointed agents, each of which may do so pursuant to such appointment
with regard to all or any part of such principal amount.

     Section 1.5  Notices, Etc. to the Trustee and the Company

     Any request, demand, authorization, direction, notice, consent, waiver or
Act of Holders or other document provided or permitted by this Indenture to be
made upon, given or furnished to, or filed with,

     (1)  the Trustee by any Holder, any holder of Preferred Securities or the
Company shall be sufficient for every purpose hereunder if made, given,
furnished or filed in writing to or with the Trustee at its Corporate Trust
Office, or

     (2)  the Company by the Trustee, any Holder or any holder of Preferred
Securities shall be sufficient for every purpose (except as otherwise provided
in Section 5.1) hereunder if in writing and mailed, first class, postage
prepaid, to the Company addressed to it at the address of its principal office
specified in the first paragraph of this instrument or at any other address
previously furnished in writing to the Trustee by the Company.

     Section 1.6  Notice to Holders; Waiver.

     Where this Indenture provides for notice to Holders of any event, such
notice shall be sufficiently given (unless otherwise herein expressly provided)
if in writing and mailed, first class postage prepaid, to each Holder affected
by such event, at the address of such Holder as it appears in the Securities
Register, not later than the latest date, and not earlier than the earliest
date, prescribed for the giving of such notice. In any case where notice to
Holders is given by mail, neither the failure to mail such notice, nor any
defect in any notice so mailed, to any particular Holder shall affect the
sufficiency of such notice with respect to other Holders. Where this Indenture
provides for notice in any manner, such notice may be waived in writing by the
Person entitled to receive such notice, either before or after the event, and
such waiver shall be the equivalent of such notice. Waivers of notice by Holders
shall be filed with the Trustee, but such filing shall not be a condition
precedent to the validity of any action taken in reliance upon such waiver.

                                       12
<PAGE>

     Section 1.7    Conflict with Trust Indenture Act.

     If any provision of this Indenture limits, qualifies or conflicts with the
duties imposed by any of Sections 310 to 317, inclusive, of the Trust Indenture
Act, through operation of Section 318(c) thereof, such imposed duties shall
control.

     Section 1.8    Effect of Headings and Table of Contents.

     The Article and Section headings herein and the Table of Contents are for
convenience only and shall not affect the construction hereof.

     Section 1.9    Successors and Assigns.

     All covenants and agreements in this Indenture by the Company shall bind
each of its successors and assigns, whether so expressed or not.

     Section 1.10   Separability Clause.

     In case any provision in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

     Section 1.11   Benefits of Indenture.

     Nothing in this Indenture or in the Securities, express or implied, shall
give to any Person, other than the parties hereto and their successors and
assigns, the holders of Senior Debt of the Company, the Holders of the
Securities and, to the extent expressly provided in Sections 5.2, 5.8, 5.9,
5.11, 5.13, 9.1 and 9.2, the holders of Preferred Securities, any benefit or any
legal or equitable right, remedy or claim under this Indenture.

     Section 1.12   Governing Law.

     This Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York without regard to the
principles of conflicts thereof.

     Section 1.13   Non-Business Days.

     In any case where any Interest Payment Date, Redemption Date or Stated
Maturity of any Security shall not be a Business Day, then (notwithstanding any
other provision of this Indenture or such Security) payment of interest or
principal (and premium, if any) need not be made on such date, but may be made
on the next succeeding Business Day (and no interest shall accrue for the period
from and after such Interest Payment Date, Redemption Date or Stated Maturity,
as the case may be, until such next succeeding Business Day except that, if such
Business Day is in the next succeeding calendar year, such payment shall be made
on the immediately preceding Business Day (in each case with the same force and
effect as if made on the Interest Payment Date or Redemption Date or at the
Stated Maturity).

                                       13
<PAGE>

                                  ARTICLE II

                                SECURITY FORMS

     Section 2.1  Forms Generally.

     The Securities of each series and the Trustee's certificate of
authentication shall be in substantially the forms set forth in this Article, or
in such other form or forms as shall be established by or pursuant to a Board
Resolution and as set forth in an Officers' Certificate or in one or more
indentures supplemental hereto, in each case with such appropriate insertions,
omissions, substitutions and other variations as are required or permitted by
this Indenture and may have such letters, numbers or other marks of
identification and such legends or endorsements placed thereon as may be
required to comply with applicable tax laws or the rules of any securities
exchange or as may, consistently herewith, be determined by the officers
executing such Securities, as evidenced by their execution of the Securities.
If the form of Securities of any series is established by action taken pursuant
to a Board Resolution, a copy of an appropriate record of such action shall be
certified by the Secretary or an Assistant Secretary of the Company and
delivered to the Trustee at or prior to the delivery of the Company Order
contemplated by Section 3.3 with respect to the authentication and delivery of
such Securities.

     The Trustee's certificates of authentication shall be substantially in the
form set forth in this Article.

     The definitive Securities shall be printed, lithographed or engraved or
produced by any combination of these methods, if required by any securities
exchange on which the Securities may be listed, on a steel engraved border or
steel engraved borders or may be produced in any other manner permitted by the
rules of any securities exchange on which the Securities may be listed, all as
determined by the officers executing such Securities, as evidenced by their
execution of such securities.

     Section 2.2  Form of Face of Security.

                                  ONEOK, INC.
                              (TITLE OF SECURITY)

No.                                                                  $__________

     ONEOK, INC., a corporation organized and existing under the laws of
Oklahoma (the "Company," which term includes any successor corporation under the
Indenture hereinafter referred to), for value received, hereby promises to pay
to _____________________, or registered assigns, the principal sum of
_______________ Dollars ($ ________) on _________ __, ____ [if applicable,
insert--;provided that the Company may (i) shorten the Stated Maturity of the
principal of this Security to a date not earlier than ___________ __, ____ and
(ii) extend the Stated Maturity of the principal of this Security at any time on
one or more occasions, subject to certain conditions specified in Section 3.14
of the Indenture, but in no event to a date later than __________].  The Company
further promises to pay interest on said principal sum from ____________ __,
____ or from the most recent interest payment date (each such date, an "Interest
Payment Date") on which interest has been paid or duly provided for, [monthly]
[quarterly] [semi-annually] [if applicable, insert--(subject to

                                       14
<PAGE>

deferral as set forth herein)] in arrears on _____________, ___________,
____________ and ___________ of each year, commencing _____________,
_____________, at the rate of ___% per annum, until the principal hereof shall
have become due and payable, [if applicable, insert--plus Additional Interest,
if any,] until the principal hereof is paid or duly provided for or made
available for payment [if applicable, insert--and on any overdue principal and
(without duplication and to the extent that payment of such interest is
enforceable under applicable law) on any overdue installment of interest at the
rate of ___% per annum, compounded [monthly] [quarterly] [semi-annually]]. The
amount of interest payable for any period shall be computed on the basis of
twelve 30-day months and a 360-day year. The amount of interest payable for any
partial period shall be computed on the basis of the number of days elapsed in a
360-day year of twelve 30-day months. In the event that any date on which
interest is payable on this Security is not a Business Day, then a payment of
the interest payable on such date will be made on the next succeeding day which
is a Business Day (and without any interest or other payment in respect of any
such delay), except that, if such Business Day is in the next succeeding
calendar year, such payment shall be made on the immediately preceding Business
Day, in each case with the same force and effect as if made on the date the
payment was originally payable. A "Business Day" shall mean any day other than
(i) a Saturday or Sunday, (ii) a day on which banking institutions in The City
of New York are authorized or required by law or executive order to remain
closed or (iii) a day on which the Corporate Trust Office of the Trustee [if
applicable, insert--, or the principal office of the Property Trustee under the
Trust Agreement hereinafter referred to for ONEOK Capital Trust________,] is
closed for business. The interest installment so payable, and punctually paid or
duly provided for, on any Interest Payment Date will, as provided in the
Indenture, be paid to the Person in whose name this Security (or one or more
Predecessor Securities) is registered at the close of business on the Regular
Record Date for such interest installment, which shall be (i) in the case of
Securities represented by one or more Global Securities, the Business Day next
preceding such Interest Payment Date and (ii) in the case of Securities not
represented by one or more Global Securities, the date which is fifteen days
next preceding such Interest Payment Date (whether or not a Business Day). Any
such interest installment not so punctually paid or duly provided for shall
forthwith cease to be payable to the Holder on such Regular Record Date and may
either be paid to the Person in whose name this Security (or one or more
Predecessor Securities) is registered at the close of business on a Special
Record Date for the payment of such Defaulted Interest to be fixed by the
Trustee, notice whereof shall be given to Holders of Securities of this series
not less than 10 days prior to such Special Record Date, or be paid at any time
in any other lawful manner not inconsistent with the requirements of any
securities exchange on which the Securities of this series may be listed, and
upon such notice as may be required by such exchange, all as more fully provided
in said Indenture.

     [If applicable, insert--So long as no Event of Default has occurred and is
continuing, the Company shall have the right at any time during the term of this
Security to defer payment of interest on this Security, at any time or from time
to time, for up to ___ consecutive [monthly] [quarterly] [semi-annual] interest
payment periods with respect to each deferral period (each an "Extension
Period"), during which Extension Periods the Company shall have the right to
make partial payments of interest on any Interest Payment Date, and at the end
of which the Company shall pay all interest then accrued and unpaid (together
with Additional Interest thereon to the extent permitted by applicable law);
provided, however, that no Extension Period shall extend beyond the Stated
Maturity of the principal of this Security; provided, further, that during any
such Extension Period, the Company shall not, (i) declare or pay any dividends
or distributions or redeem, purchase, acquire or make a liquidation payment with
respect to, any of its capital stock or (ii) make any payment of

                                       15
<PAGE>

principal of or interest or premium, if any, on or repay, repurchase or redeem
any debt security issued by it that ranks pari passu with or junior in interest
to this Security or make any guarantee payments with respect to any guarantee by
the Company of any debt securities of any of its Subsidiaries if such guarantee
ranks pari passu with or junior in interest to this Security (other than (a)
dividends or distributions in Common Stock, (b) any declaration of a dividend in
connection with the implementation of a Rights Plan, the issuance of any Common
Stock or any class or series of preferred stock of the Company under any Rights
Plan or the repurchase of any rights distributed pursuant to a Rights Plan, and
(c) purchases of Common Stock related to the issuance of Common Stock under any
of the Company's benefit plans for their respective directors, officers or
employees). Prior to the termination of any such Extension Period, the Company
may further extend the interest payment period, provided that no Extension
Period shall ___ exceed consecutive [months] [quarters] [semi-annual periods] or
extend beyond the Stated Maturity of the principal of this Security. Upon the
termination of any such Extension Period and upon the payment of all accrued and
unpaid interest and any Additional Interest then due, the Company may elect to
begin a new Extension Period, subject to the above requirements. No interest
shall be due and payable during an Extension Period except at the end thereof.
The Company shall give the Holder of this Security and the Trustee notice of its
election to begin any Extension Period at least one Business Day prior to the
next succeeding Interest Payment Date on which interest on this Security would
be payable but for such deferral [if applicable, insert -- or, with respect to
the Securities issued to a ONEOK Capital Trust, so long as such Securities are
held by such ONEOK Capital Trust, prior to the earlier of (i) the next
succeeding date on which Distributions on the Preferred Securities of such ONEOK
Capital Trust would be payable but for such deferral or (ii) the date the
Administrative Trustee is required to give notice to any securities exchange or
other applicable self regulatory organization or to holders of such Preferred
Securities of the record date or the date such Distributions are payable, but in
any event not less than one Business Day prior to such record date].

     Payment of the principal of (and premium, if any) and interest on this
Security will be made at the office or agency of the Company maintained for that
purpose in the United States, in such coin or currency of the United States of
America as at the time of payment is legal tender for payment of public and
private debts [if applicable, insert--; provided, however, that at the option of
the Company payment of interest may be made (i) by check mailed to the address
of the Person entitled thereto as such address shall appear in the Securities
Register or (ii) by wire transfer in immediately available funds at such place
and to such account as may be designated by the Person entitled thereto as
specified in the Securities Register].

     The indebtedness evidenced by this Security is, to the extent provided in
the Indenture, subordinate and subject in right of payments to the prior payment
in full of all Senior Debt of the Company, and this Security is issued subject
to the provisions of the Indenture with respect thereto. Each Holder of this
Security, by accepting the same, (a) agrees to and shall be bound by such
provisions, (b) authorizes and directs the Trustee on his behalf to take such
actions as may be necessary or appropriate to effectuate the subordination so
provided and (c) appoints the Trustee his attorney-in-fact for any and all such
purposes. Each Holder hereof, by his acceptance hereof, waives all notice of the
acceptance of the subordination provisions contained herein and in the Indenture
by each holder of Senior Debt of the Company, whether now outstanding or
hereafter incurred, and waives reliance by each such holder upon said
provisions.

                                       16
<PAGE>

     Reference is hereby made to the further provisions of this Security set
forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Security
shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed under its corporate seal.

Dated:

                                        ONEOK, INC.


                                        By:_____________________________________
                                        [President or Vice President]
Attest:
_____________________________________
[Secretary or Assistant Secretary]

     SWORN TO ME and subscribed in my presence in the City of ___________, State
of _____________ this ___ day of __________, 19____.


                                        ________________________________________
                                        Notary Public

                                        Commission Expires: ____________________

                                        [NOTARIAL SEAL]

     Section 2.3  Form of Reverse of Security.

     This Security is one of a duly authorized issue of securities of the
Company (the "Securities"), issued and to be issued in one or more series under
the Junior Subordinated Indenture dated as of [__________], 1999 (the
"Indenture") between the Company and [______________________], as Trustee
(herein called the "Trustee," which term includes any successor trustee under
the Indenture), to which Indenture and all indentures supplemental thereto
reference is hereby made for a statement of the respective rights, limitations
of rights, duties and immunities thereunder of the Trustee, the Company and the
Holders of the Securities, and of the terms upon which the Securities are, and
are to be, authenticated and delivered. This Security is one of the series
designated on the face hereof [if applicable, insert--, limited in aggregate
principal amount to $___________].

     All terms used in this Security that are defined in the Indenture [if
applicable, insert -- or in the Amended and Restated Trust Agreement dated as of
____________ ____, ____, as amended (the "Trust Agreement"), for ONEOK Capital
Trust_______, among the Company, as Depositor, and the

                                       17
<PAGE>

Trustees named therein, shall have the meanings assigned to them in the
Indenture [if applicable, insert--or the Trust Agreement, as the case may be].

     [If applicable, insert--The Company may at any time, at its option, on or
after ________, ___, and subject to the terms and conditions of Article XI of
the Indenture, redeem this Security in whole at any time or in part from time to
time, without premium or penalty, at a redemption price equal to 100% of the
principal amount thereof plus accrued and unpaid interest [if applicable,
insert--,including Additional Interest, if any,] to the Redemption Date.]

     [If applicable, insert--Upon the occurrence and during the continuation of
a Special Event in respect of a ONEOK Capital Trust, the Company may, at its
option, at any time within 90 days of the occurrence of such Special Event
redeem this Security, in whole but not in part, subject to the provisions of
Section 11.7 and the other provisions of Article XI of the Indenture, at a
redemption price equal to 100% of the principal amount thereof plus accrued and
unpaid interest, including Additional Interest, if any, to the Redemption Date.]

     In the event of redemption of this Security in part only, a new Security or
Securities of this series for the unredeemed portion hereof will be issued in
the name of the Holder hereof upon the cancellation hereof.

     The Indenture contains provisions for satisfaction and discharge of the
entire indebtedness of this Security upon compliance by the Company with certain
conditions set forth in the Indenture.

     The Indenture permits, with certain exceptions as therein provided, the
Company and the Trustee at any time to enter into a supplemental indenture or
indentures for the purpose of modifying in any manner the rights and obligations
of the Company and of the Holders of the Securities, with the consent of the
Holders of not less than a majority in principal amount of the Outstanding
Securities of each series to be affected by such supplemental indenture.  The
Indenture also contains provisions permitting Holders of specified percentages
in principal amount of the Securities of each series at the time Outstanding, on
behalf of the Holders of all Securities of such series, to waive compliance by
the Company with certain provisions of the Indenture and certain past defaults
under the Indenture and their consequences.  Any such consent or waiver by the
Holder of this Security shall be conclusive and binding upon such Holder and
upon all future Holders of this Security and of any Security issued upon the
registration of transfer hereof or in exchange herefor or in lieu hereof,
whether or not notation of such consent or waiver is made upon this Security.

     [If the Security is not a Discount Security,--As provided in and subject to
the provisions of the Indenture, if an Event of Default with respect to the
Securities of this series at the time Outstanding occurs and is continuing, then
and in every such case the Trustee or the Holders of not less than 25% in
principal amount of the Outstanding Securities of this series may declare the
principal amount of all the Securities of this series to be due and payable
immediately, by a notice in writing to the Company (and to the Trustee if given
by Holders), provided that, in the case of the Securities of this series issued
to a ONEOK Capital Trust, if upon an Event of Default, the Trustee or the
Holders of not less than 25% in principal amount of the Outstanding Securities
of this series fail to declare the principal of all the Securities of this
series to be immediately due and payable, the holders of at least 25% in
aggregate Liquidation Amount of the Preferred Securities then outstanding of
such ONEOK Capital Trust shall have such right by a notice in writing to the
Company and the

                                       18
<PAGE>

Trustee; and upon any such declaration the principal amount of and the accrued
interest (including any Additional Interest) on all the Securities of this
series shall become immediately due and payable, provided that the payment of
principal and interest (including any Additional Interest) on such Securities
shall remain subordinated to the extent provided in Article XIII of the
Indenture.]

     [If the Security is a Discount Security,--As provided in and subject to the
provisions of the Indenture, if an Event of Default with respect to the
Securities of this series at the time Outstanding occurs and is continuing, then
and in every such case the Trustee or the Holders of not less than such portion
of the principal amount as may be specified in the terms of the Securities of
this series may declare an amount of principal of the Securities of this series
to be due and payable immediately, by a notice in writing to the Company (and to
the Trustee if given by Holders), provided that, in the case of the Securities
of this series issued to a ONEOK Capital Trust, if upon an Event of Default, the
Trustee or the Holders of not less than 25% in principal amount of the
Outstanding Securities of this series fails to declare the principal of all the
Securities of this series to be immediately due and payable, the holders of at
least 25% in aggregate Liquidation Amount of the Preferred Securities then
outstanding of such ONEOK Capital Trust shall have such right by a notice in
writing to the Company and the Trustee.  The amount of principal of the
Securities of this series that may be declared due and payable shall be equal
to--insert formula for determining the amount.  Upon any such declaration, such
amount of the principal of and the accrued interest (including any Additional
Interest) on all the Securities of this series shall become immediately due and
payable, provided that the payment of principal and interest (including any
Additional Interest) on such Securities shall remain subordinated to the extent
provided in Article XIII of the Indenture.  Upon payment (i) of the amount of
principal so declared due and payable and (ii) of interest on any overdue
principal and overdue interest (in each case to the extent that the payment of
such interest shall be legally enforceable), all of the Company's obligations in
respect of the payment of the principal of and interest, if any, on this
Security shall terminate.]

     No reference herein to the Indenture and no provision of this Security or
of the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of (and premium, if any) and
interest on this Security at the times, place and rate, and in the coin or
currency, herein prescribed.

     As provided in the Indenture and subject to certain limitations therein set
forth, the transfer of this Security is registerable in the Securities Register,
upon surrender of this Security for registration of transfer at the office or
agency of the Company maintained under Section 10.2 of the Indenture duly
endorsed by, or accompanied by a written instrument of transfer in form
satisfactory to the Company and the Securities Registrar duly executed by, the
Holder hereof or his attorney duly authorized in writing, and thereupon one or
more new Securities of this series, of authorized denominations and for the same
aggregate principal amount, will be issued to the designated transferee or
transferees.  No service charge shall be made for any such registration of
transfer or exchange, but the Company may require payment of a sum sufficient to
cover any tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Security for registration of transfer, the
Company, the Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this Security is registered as the owner hereof for all
purposes, whether or not this Security be overdue, and none of the Company, the
Trustee or any such agent shall be affected by notice to the contrary.

                                       19
<PAGE>

     The Securities of this series are issuable only in registered form without
coupons in denominations of [$25] and any integral multiple thereof.  As
provided in the Indenture and subject to certain limitations therein set forth,
Securities of this series are exchangeable for a like aggregate principal amount
of Securities of such series of a different authorized denomination, as
requested by the Holder surrendering the same.

     The Company by its acceptance of this Security or a beneficial interest
therein, the Holder of, and any Person that acquires a beneficial interest in,
this Security agree that for United States federal, state and local tax purposes
it is intended that this Security constitute indebtedness.

     THE INDENTURE AND THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO CONFLICTS OF
LAWS PRINCIPLES THEREOF.

     Section 2.4  Additional Provisions Required in Global Security.

     Any Global Security issued hereunder shall, in addition to the provisions
contained in Sections 2.2 and 2.3, bear a legend in substantially the following
form:

     "This Security is a Global Security within the meaning of the Indenture
hereinafter referred to and is registered in the name of a Depositary or a
nominee of a Depositary.  This Security is exchangeable for Securities
registered in the name of a person other than the Depositary or its nominee only
in the limited circumstances described in the Indenture and may not be
transferred except as a whole by the Depositary to a nominee of the Depositary
or by a nominee of the Depositary to the Depositary or another nominee of the
Depositary."

     Section 2.5  Form of Trustee's Certificate of Authentication.

     This is one of the Securities referred to in the within-mentioned
Indenture.

Dated:

_______________________________
as Trustee


_______________________________
By:
     Authorized officer

                                       20
<PAGE>

                                  ARTICLE III

                                THE SECURITIES

     Section 3.1    Title and Terms.

     The aggregate principal amount of Securities which may be authenticated and
delivered under this Indenture is unlimited.

     The Securities may be issued in one or more series.  There shall be
established in or pursuant to a Board Resolution and set forth in an Officers'
Certificate, or established in one or more indentures supplemental hereto, prior
to the issuance of Securities of a series:

     (a)   the title of the Securities of such series, which shall distinguish
the Securities of the series from all other Securities;

     (b)   the limit, if any, upon the aggregate principal amount of the
Securities of such series which may be authenticated and delivered under this
Indenture (except for Securities authenticated and delivered upon registration
of transfer of, or in exchange for, or in lieu of, other Securities of the
series pursuant to Section 3.4, 3.5, 3.6, 9.6 or 11.6 and except for any
Securities which, pursuant to Section 3.3, are deemed never to have been
authenticated and delivered hereunder); provided, however, that the authorized
aggregate principal amount of such series may be increased above such amount by
a Board Resolution to such effect;

     (c)   the Stated Maturity or Maturities on which the principal of the
Securities of such series is payable or the method of determination thereof;

     (d)   the rate or rates, if any, at which the Securities of such series
shall bear interest, if any, the rate or rates and extent to which Additional
Interest, if any, shall be payable in respect of any Securities of such series,
the Interest Payment Dates on which such interest shall be payable, the right,
pursuant to Section 3.11 or as otherwise set forth therein, of the Company to
defer or extend an Interest Payment Date, and the Regular Record Date for the
interest payable on any Interest Payment Date or the method by which any of the
foregoing shall be determined;

     (e)   the place or places where the principal of (and premium, if any) and
interest on the Securities of such series shall be payable, the place or places
where the Securities of such series may be presented for registration of
transfer or exchange, and the place or places where notices and demands to or
upon the Company in respect of the Securities of such series may be made;

     (f)   the period or periods within or the date or dates on which, if any,
the price or prices at which and the terms and conditions upon which the
Securities of such series may be redeemed, in whole or in part, at the option of
the Company;

     (g)   the obligation or the right, if any, of the Company to redeem, repay
or purchase the Securities of such series pursuant to any sinking fund,
amortization or analogous provisions, and the period or periods within which,
the price or prices at which, the currency or currencies (including

                                       21
<PAGE>

currency unit or units) in which and the other terms and conditions upon which
Securities of the series shall be redeemed, repaid or purchased, in whole or in
part, pursuant to such obligation;

     (h)   the denominations in which any Securities of such series shall be
issuable, if other than denominations of [$25] and any integral multiple
thereof;

     (i)   if other than Dollars, the currency or currencies (including currency
unit or units) in which the principal of (and premium, if any) and interest, if
any, on the Securities of the series shall be payable, or in which the
Securities of the series shall be denominated;

     (j)   the additions, modifications or deletions, if any, in the Events of
Default or covenants of the Company set forth herein with respect to the
Securities of such series;

     (k)   if other than the principal amount thereof, the portion of the
principal amount of Securities of such series that shall be payable upon
declaration of acceleration of the Maturity thereof;

     (l)   the additions or changes, if any, to this Indenture with respect to
the Securities of such series as shall be necessary to permit or facilitate the
issuance of the Securities of such series in bearer form, registerable or not
registerable as to principal, and with or without interest coupons;

     (m)   any index or indices used to determine the amount of payments of
principal of and premium, if any, on the Securities of such series or the manner
in which such amounts will be determined;

     (n)   whether the Securities of the series, or any portion thereof, shall
initially be issuable in the form of a temporary Global Security representing
all or such portion of the Securities of such series and provisions for the
exchange of such temporary Global Security for definitive Securities of such
series;

     (o)   if applicable, that any Securities of the series shall be issuable in
whole or in part in the form of one or more Global Securities and, in such case,
the respective Depositaries for such Global Securities, the form of any legend
or legends which shall be borne by any such Global Security in addition to or in
lieu of that set forth in Section 2.4 and any circumstances in addition to or in
lieu of those set forth in Section 3.5 in which any such Global Security may be
exchanged in whole or in part for Securities registered, and any transfer of
such Global Security in whole or in part may be registered, in the name or names
of Persons other than the Depositary for such Global Security or a nominee
thereof;

     (p)   the appointment of any Paying Agent or Agents for the Securities of
such series;

     (q)   the terms of any right to convert or exchange Securities of such
series into any other securities or property of the Company, and the additions
or changes, if any, to this Indenture with respect to the Securities of such
series to permit or facilitate such conversion or exchange;

     (r)   the form or forms of the Trust Agreement, Amended and Restated Trust
Agreement and Guarantee Agreement;

                                       22
<PAGE>

     (s)   the relative degree, if any, to which the Securities of the series
shall be senior to or be subordinated to other series of Securities in right of
payment, whether such other series of Securities are Outstanding or not; and

     (t)   any other terms of the Securities of such series (which terms shall
not be inconsistent with the provisions of this Indenture).

     All Securities of any one series shall be substantially identical except as
to denomination and except as may otherwise be provided herein or in or pursuant
to such Board Resolution and set forth in such Officers' Certificate, or in any
such indenture supplemental hereto.

     If any of the terms of the series are established by action taken pursuant
to a Board Resolution, a copy of an appropriate record of such action shall be
certified by the Secretary or an Assistant Secretary and delivered to the
Trustee at or prior to the delivery of the Officers' Certificate of the Company
setting forth the terms of the series.

     The Securities shall be subordinated in right of payment to Senior Debt of
the Company as provided in Article XIII.

     Section 3.2    Denominations.

     The Securities of each series shall be in registered form without coupons
and shall be issuable in denominations of [$25] and any integral multiple
thereof, unless otherwise specified as contemplated by Section 3.1.

     Section 3.3    Execution, Authentication, Delivery and Dating.

     The Securities shall be executed on behalf of the Company by its President
or one of its Vice Presidents under its corporate seal reproduced or impressed
thereon and attested by its Secretary or one of its Assistant Secretaries.  The
signature of any of these officers on the Securities may be manual or facsimile.

     Securities bearing the manual or facsimile signatures of individuals who
were at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such Securities or did not
hold such offices at the date of such Securities.  At any time and from time to
time after the execution and delivery of this Indenture, the Company may deliver
Securities of any series executed by the Company to the Trustee for
authentication, together with a Company Order for the authentication and
delivery of such Securities, and the Trustee in accordance with the Company
Order shall authenticate and deliver such Securities.  If the form or terms of
the Securities of the series have been established by or pursuant to one or more
Board Resolutions as permitted by Sections 2.1 and 3.1, in authenticating such
Securities, and accepting the additional responsibilities under this Indenture
in relation to such Securities, the Trustee shall be entitled to receive, and
(subject to Section 6.1) shall be fully protected in relying upon, an Opinion of
Counsel stating,

                                       23
<PAGE>

          (1)  if the form of such Securities has been established by or
     pursuant to Board Resolution as permitted by Section 2.1, that such form
     has been establishe d in conformity with the provisions of this Indenture;

          (2)  if the terms of such Securities have been established by or
     pursuant to Board Resolution as permitted by Section 3.1, that such terms
     have been established in conformity with the provisions of this Indenture;
     and

          (3)  that such Securities, when authenticated and delivered by the
     Trustee and issued by the Company in the manner and subject to any
     conditions specified in such Opinion of Counsel, will constitute valid and
     legally binding obligations of the Company enforceable in accordance with
     their terms, subject to bankruptcy, insolvency, fraudulent transfer,
     reorganization, moratorium and similar laws of general applicability
     relating to or affecting creditors' rights and to general equity
     principles.

If such form or terms have been so established, the Trustee shall not be
required to authenticate such Securities if the issue of such Securities
pursuant to this Indenture will affect the Trustee's own rights, duties or
immunities under the Securities and this Indenture or otherwise in a manner
which is not reasonably acceptable to the Trustee.

     Notwithstanding the provisions of Section 3.1 and of the preceding
paragraph, if all Securities of a series are not to be originally issued at one
time, it shall not be necessary to deliver the Officers' Certificate of the
Company otherwise required pursuant to Section 3.1 or the Company Order and
Opinion of Counsel of the Company otherwise required pursuant to such preceding
paragraph at or prior to the authentication of each Security of such series if
such documents are delivered at or prior to the authentication upon original
issuance of the first Security of such series to be issued.

     Each Security shall be dated the date of its authentication.

     No Security shall be entitled to any benefit under this Indenture or be
valid or obligatory for any purpose, unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by the manual signature of one of its authorized
officers, and such certificate upon any Security shall be conclusive evidence,
and the only evidence, that such Security has been duly authenticated and
delivered hereunder.  Notwithstanding the foregoing, if any Security shall have
been authenticated and delivered hereunder but never issued and sold by the
Company, and the Company shall deliver such Security to the Trustee for
cancellation as provided in Section 3.9, for all purposes of this Indenture such
Security shall be deemed never to have been authenticated and delivered
hereunder and shall never be entitled to the benefits of this Indenture.

     Section 3.4    Temporary Securities.

     Pending the preparation of definitive Securities of any series, the Company
may execute, and upon Company Order the Trustee shall authenticate and deliver,
temporary Securities which are printed, lithographed, typewritten, mimeographed
or otherwise produced, in any denomination, substantially of the tenor of the
definitive Securities of such series in lieu of which they are issued and

                                       24
<PAGE>

with such appropriate insertions, omissions, substitutions and other variations
as the officers executing such Securities may determine, as evidenced by their
execution of such Securities.

     If temporary Securities of any series are issued, the Company will cause
definitive Securities of such series to be prepared without unreasonable delay.
After the preparation of definitive Securities, the temporary Securities shall
be exchangeable for definitive Securities upon surrender of the temporary
Securities at the office or agency of the Company designated for that purpose
without charge to the Holder.  Upon surrender for cancellation of any one or
more temporary Securities, the Company shall execute and the Trustee shall
authenticate and deliver in exchange therefor one or more definitive Securities
of the same series, of any authorized denominations having the same Original
Issue Date and Stated Maturity and having the same terms as such temporary
Securities. Until so exchanged, the temporary Securities of any series shall in
all respects be entitled to the same benefits under this Indenture as definitive
Securities of such series.

     Section 3.5    Registration, Transfer and Exchange.

     The Company shall cause to be kept at the Corporate Trust Office of the
Trustee a register in which, subject to such reasonable regulations as it may
prescribe, the Company shall provide for the registration of Securities and of
transfers of Securities.  Such register is herein sometimes referred to as the
"Securities Register." The Trustee is hereby appointed "Securities Registrar"
for the purpose of registering Securities and transfers of Securities as herein
provided.

     Upon surrender for registration of transfer of any Security at the office
or agency of the Company designated for that purpose the Company shall execute,
and the Trustee shall authenticate and deliver, in the name of the designated
transferee or transferees, one or more new Securities of the same series of any
authorized denominations, of a like aggregate principal amount, of the same
Original Issue Date and Stated Maturity and having the same terms.

     At the option of the Holder, Securities may be exchanged for other
Securities of the same series of any authorized denominations, of a like
aggregate principal amount, of the same Original Issue Date and Stated Maturity
and having the same terms, upon surrender of the Securities to be exchanged at
such office or agency.  Whenever any securities are so surrendered for exchange,
the Company shall execute, and the Trustee shall authenticate and deliver, the
Securities which the Holder making the exchange is entitled to receive.

     All Securities issued upon any transfer or exchange of Securities shall be
the valid obligations of the Company, evidencing the same debt, and entitled to
the same benefits under this Indenture, as the Securities surrendered upon such
transfer or exchange.

     Every Security presented or surrendered for transfer or exchange shall (if
so required by the Company or the Securities Registrar) be duly endorsed, or be
accompanied by a written instrument of transfer in form satisfactory to the
Company and the Securities Registrar, duly executed by the Holder thereof or his
attorney duly authorized in writing.

     No service charge shall be made to a Holder for any transfer or exchange of
Securities, but the Company may require payment of a sum sufficient to cover any
tax or other governmental charge that may be imposed in connection with any
transfer or exchange of Securities.

                                       25
<PAGE>

The provisions of Clauses (1), (2), (3) and (4) below shall apply only to
Global Securities:

          (1)  Each Global Security authenticated under this Indenture shall be
     registered in the name of the Depositary designated for such Global
     Security or a nominee thereof and delivered to such Depositary or a nominee
     thereof or custodian therefor, and each such Global Security shall
     constitute a single Security for all purposes of this Indenture.

          (2)  Notwithstanding any other provision in this Indenture, no Global
     Security may be exchanged in whole or in part for Securities registered,
     and no transfer of a Global Security in whole or in part may be registered,
     in the name of any Person other than the Depositary for such Global
     Security or a nominee thereof unless (A) such Depositary (i) has notified
     the Company that it is unwilling or unable to continue as Depositary for
     such Global Security or (ii) has ceased to be a clearing agency registered
     under the Exchange Act at a time when the Depositary is required to be so
     registered to act as depositary, in each case unless the Company has
     approved a successor Depositary within 90 days, (B) there shall have
     occurred and be continuing an Event of Default with respect to such Global
     Security, (C) the Company in its sole discretion determines that such
     Global Security will be so exchangeable or transferable or (D) there shall
     exist such circumstances, if any, in addition to or in lieu of the
     foregoing as have been specified for this purpose as contemplated by
     Section 3.1.

          (3)  Subject to Clause (2) above, any exchange of a Global Security
     for other Securities may be made in whole or in part, and all Securities
     issued in exchange for a Global Security or any portion thereof shall be
     registered in such names as the Depositary for such Global Security shall
     direct.

          (4)  Every Security authenticated and delivered upon registration of
     transfer of, or in exchange for or in lieu of, a Global Security or any
     portion thereof, whether pursuant to this Section, Section 3.4, 3.6, 9.6 or
     11.6 or otherwise, shall be authenticated and delivered in the form of, and
     shall be, a Global Security, unless such Security is registered in the name
     of a Person other than the Depositary for such Global Security or a nominee
     thereof.

     Neither the Company nor the Trustee shall be required, pursuant to the
provisions of this Section, (a) to issue, transfer or exchange any Security of
any series during a period beginning at the opening of business 15 days before
the day of selection for redemption of Securities pursuant to Article XI and
ending at the close of business on the day of mailing of notice of redemption or
(b) to transfer or exchange any Security so selected for redemption in whole or
in part, except, in the case of any Security to be redeemed in part, any portion
thereof not to be redeemed.

     Section 3.6    Mutilated, Destroyed, Lost and Stolen Securities.

     If any mutilated Security is surrendered to the Trustee together with such
security or indemnity as may be required by the Company or the Trustee to save
each of them harmless, the Company shall execute and the Trustee shall
authenticate and deliver in exchange therefor a new Security of the same issue
and series of like tenor and principal amount, having the same Original Issue
Date and Stated Maturity, and bearing a number not contemporaneously
outstanding.

                                       26
<PAGE>

     If there shall be delivered to the Company and to the Trustee (i) evidence
to their satisfaction of the destruction, loss or theft of any Security, and
(ii) such security or indemnity as may be required by them to save each of them
harmless, then, in the absence of notice to the Company, or the Trustee that
such Security has been acquired by a bona fide purchaser, the Company shall
execute and, upon the Company's request, the Trustee shall authenticate and
deliver, in lieu of any such destroyed, lost or stolen Security, a new Security
of the same issue and series of like tenor and principal amount, having the same
Original Issue Date and Stated Maturity as such destroyed, lost or stolen
Security, and bearing a number not contemporaneously outstanding.

     In case any such mutilated, destroyed, lost or stolen Security has become
or is about to become due and payable, the Company in its discretion may,
instead of issuing a new Security, pay such Security.

     Upon the issuance of any new Security under this Section, the Company may
require the payment of a sum sufficient to cover any tax or other governmental
charge that may be imposed in relation thereto and any other expenses (including
the fees and expenses of the Trustee) connected therewith.

     Every new Security issued pursuant to this Section in lieu of any
destroyed, lost or stolen Security shall constitute an original additional
contractual obligation of the Company, whether or not the destroyed, lost or
stolen Security shall be at any time enforceable by anyone, and shall be
entitled to all the benefits of this Indenture equally and proportionately with
any and all other Securities duly issued hereunder.

     The provisions of this Section are exclusive and shall preclude (to the
extent lawful) all other rights and remedies with respect to the replacement or
payment of mutilated, destroyed, lost or stolen Securities.

     Secton 3.7     Payment of Interest; Interest Rights Preserved.

     Interest on any Security of any series which is payable, and is punctually
paid or duly provided for, on any Interest Payment Date, shall be paid to the
Person in whose name that Security (or one or more Predecessor Securities) is
registered at the close of business on the Regular Record Date for such interest
in respect of Securities of such series, except that, unless otherwise provided
in the Securities of such series, interest payable on the Stated Maturity of the
principal of a Security shall be paid to the Person to whom principal is paid.
The initial payment of interest on any Security of any series which is issued
between a Regular Record Date and the related Interest Payment Date shall be
payable as provided in such Security or in the Board Resolution pursuant to
Section 3.1 with respect to the related series of Securities.

     Any interest on any Security which is payable, but is not timely paid or
duly provided for, on any Interest Payment Date for Securities of such series
(herein called "Defaulted Interest"), shall forthwith cease to be payable to the
registered Holder on the relevant Regular Record Date by virtue of having been
such Holder, and such Defaulted Interest may be paid by the Company, at its
election in each case, as provided in Clause (1) or (2) below:

                                       27
<PAGE>

     (1)   The Company may elect to make payment of any Defaulted Interest to
the Persons in whose names the Securities of such series in respect of which
interest is in default (or their respective Predecessor Securities) are
registered at the close of business on a Special Record Date for the payment of
such Defaulted Interest, which shall be fixed in the following manner. The
Company shall notify the Trustee in writing of the amount of Defaulted Interest
proposed to be paid on each Security and the date of the proposed payment, and
at the same time the Company shall deposit with the Trustee an amount of money
equal to the aggregate amount proposed to be paid in respect of such Defaulted
Interest or shall make arrangements satisfactory to the Trustee for such deposit
prior to the date of the proposed payment, such money when deposited to be held
in trust for the benefit of the Persons entitled to such Defaulted Interest as
in this Clause provided. Thereupon the Trustee shall fix a Special Record Date
for the payment of such Defaulted Interest which shall be not more than 15 days
and not less than 10 days prior to the date of the proposed payment and not less
than 10 days after the receipt by the Trustee of the notice of the proposed
payment. The Trustee shall promptly notify the Company of such Special Record
Date and, in the name and at the expense of the Company, shall cause notice of
the proposed payment of such Defaulted Interest and the Special Record Date
therefor to be mailed, first class, postage prepaid, to each Holder of a
Security of such series at the address of such Holder as it appears in the
Securities Register not less than 10 days prior to such Special Record Date. The
Trustee may, in its discretion, in the name and at the expense of the Company,
cause a similar notice to be published at least once in a newspaper, customarily
published in the English language on each Business Day and of general
circulation in the Borough of Manhattan, The City of New York, but such
publication shall not be a condition precedent to the establishment of such
Special Record Date. Notice of the proposed payment of such Defaulted Interest
and the Special Record Date therefor having been mailed as aforesaid, such
Defaulted Interest shall be paid to the Persons in whose names the Securities of
such series (or their respective Predecessor Securities) are registered on such
Special Record Date and shall no longer be payable pursuant to the following
Clause (2).

     (2)   The Company may make payment of any Defaulted Interest in any other
lawful manner not inconsistent with the requirements of any securities exchange
on which the Securities of the series in respect of which interest is in default
may be listed and, upon such notice as may be required by such exchange (or by
the Trustee if the Securities are not listed), if after notice given by the
Company to the Trustee of the proposed payment pursuant to this Clause, such
payment shall be deemed practicable by the Trustee.

     Subject to the foregoing provisions of this Section, each Security
delivered under this Indenture upon transfer of or in exchange for or in lieu of
any other Security shall carry the rights to interest accrued and unpaid, and to
accrue, which were carried by such other Security.

     Section 3.8    Persons Deemed Owners.

     The Company, the Trustee and any agent of the Company or the Trustee may
treat the Person in whose name any Security is registered as the owner of such
Security for the purpose of receiving payment of principal of and (subject to
Section 3.7) any interest on such Security and for all other purposes
whatsoever, whether or not such Security be overdue, and none of the Company,
the Trustee or any agent of the Company or the Trustee shall be affected by
notice to the contrary.

     Section 3.9    Cancellation.

                                       28
<PAGE>

     All Securities surrendered for payment, redemption, transfer or exchange
shall, if surrendered to any Person other than the Trustee, be delivered to the
Trustee, and any such Securities and Securities surrendered directly to the
Trustee for any such purpose shall be promptly canceled by it. The Company may
at any time deliver to the Trustee for cancellation any Securities previously
authenticated and delivered hereunder which the Company may have acquired in any
manner whatsoever, and all Securities so delivered shall be promptly canceled by
the Trustee.  No Securities shall be authenticated in lieu of or in exchange for
any Securities canceled as provided in this Section, except as expressly
permitted by this Indenture.  All canceled Securities shall be destroyed by the
Trustee and the Trustee shall, if requested, deliver to the Company a
certificate of such destruction.

     Section 3.10   Computation of Interest.

     Except as otherwise specified as contemplated by Section 3.1 for Securities
of any series, interest on the Securities of each series for any period shall be
computed on the basis of a 360-day year of twelve 30-day months and interest on
the Securities of each series for any partial period shall be computed on the
basis of the number of days elapsed in a 360-day year of twelve 30-day months.

     Section 3.11   Deferrals of Interest Payment Dates.

     If specified as contemplated by Section 2.1 or Section 3.1 with respect to
the Securities of a particular series, so long as no Event of Default has
occurred and is continuing, the Company shall have the right, at any time during
the term of such series, from time to time to defer the payment of interest on
such Securities for such period or periods as may be specified as contemplated
by Section 3.1 (each, an "Extension Period"), during which Extension Periods the
Company shall have the right to make partial payments of interest on any
Interest Payment Date.  No Extension Period shall end on a date other than an
Interest Payment Date.  At the end of any such Extension Period, the Company
shall pay all interest then accrued and unpaid on the Securities (together with
Additional Interest thereon, if any, at the rate specified for the Securities of
such series to the extent permitted by applicable law); provided, however, that
no Extension Period shall extend beyond the Stated Maturity of the principal of
the Securities of such series; provided, further, that during any such Extension
Period, the Company shall not, (i) declare or pay any dividends or distributions
on, or redeem, purchase, acquire or make a liquidation payment with respect to,
any of its capital stock, or (ii) make any payment of principal of or interest
or premium, if any, on or repay, repurchase or redeem any debt security issued
by it that ranks pari passu with or junior in interest to the Securities of such
series or make any guarantee payments with respect to any guarantee by the
Company of the debt securities of any of its Subsidiaries that by their terms
rank pari passu with or junior in interest to the securities of such series
(other than (a) dividends or distributions in Common Stock, (b) any declaration
of a dividend in connection with the implementation of a Rights Plan, the
issuance of any Common Stock or any class or series of preferred stock of the
Company under any Rights Plan or the repurchase of any rights distributed
pursuant to a Rights Plan, and (c) purchases of Common Stock related to the
issuance of Common Stock under any of the Company's benefit plans for their
respective directors, officers or employees).  Prior to the termination of any
such Extension Period, the Company may further extend the interest payment
period, provided that no Extension Period shall exceed the period or periods
specified in such Securities or extend beyond the Stated Maturity of the
principal of such Securities.  Upon termination of any Extension Period and upon
the payment of all accrued and unpaid interest and any Additional Interest then
due on any Interest Payment Date, the Company may elect to begin a new Extension
Period, subject to the above requirements.  No interest

                                       29
<PAGE>

shall be due and payable during an Extension Period, except at the end thereof.
The Company shall give the Holders of the Securities of such series and the
Trustee notice of its election to begin or extend any such Extension Period at
least one Business Day prior to the next succeeding Interest Payment Date on
which interest on Securities of such series would be payable but for such
deferral or, with respect to the Securities of a series issued to a ONEOK
Capital Trust, so long as such Securities are held by such ONEOK Capital Trust,
prior to the earlier of (i) the next succeeding date on which Distributions on
the Preferred Securities of such ONEOK Capital Trust would be payable but for
such deferral or (ii) the date the Administrative Trustee of such ONEOK Capital
Trust are required to give notice to any securities exchange or other applicable
self regulatory organization or to holders of such Preferred Securities of the
record date or the date such Distributions are payable, but in any event not
less than one Business Day prior to such record date.

     The Trustee shall promptly give notice of the Company's election to begin
any such Extension Period to the Holders of the Outstanding Securities of such
series.

     Section 3.12   Right of Set-Off.

     With respect to the Securities of a series issued to a ONEOK Capital Trust,
notwithstanding anything to the contrary in the Indenture, the Company shall
have the right to set-off any payment it is otherwise required to make
thereunder in respect of any such Security to the extent the Company has
theretofore made, or is concurrently on the date of such payment making, a
payment with respect to the ONEOK Capital Guarantee relating to such Security,
or the Company has theretofore made, or is concurrently on the date of such
payment making, a payment under Section 5.8 of the Indenture.

     Section 3.13   Agreed Tax Treatment.

     Each Security issued hereunder shall provide that the Company and, by its
acceptance of a Security or a beneficial interest therein, the Holder of, and
any Person that acquires a beneficial interest in, such Security agree that for
United States federal, state and local tax purposes it is intended that such
Security constitute indebtedness.

     Section 3.14   Shortening or Extension of Stated Maturity.

     If specified as contemplated by Section 2.1 or Section 3.1 with respect to
the Securities of a particular series, the Company shall have the right to (i)
shorten the Stated Maturity of the principal of the Securities of such series at
any time to any date not earlier than the first date on which the Company has
the right to redeem the Securities of such series, and (ii) extend the Stated
Maturity of the principal of the Securities of such series at any time at its
election for one or more periods, but in no event to a date later than the
[49TH] anniversary of the first Interest Payment Date following the Original
Issue Date of the Securities of such series; provided that, if the Company
elects to exercise its right to extend the Stated Maturity of the principal of
the Securities of such series pursuant to clause (ii), above, at the time such
election is made and at the time of extension (A) the Company is not in
bankruptcy, otherwise insolvent or in liquidation, (B) the Company is not in
default in the payment of any interest or principal on such Securities, (C) in
the case of any series of Securities issued to a ONEOK Capital Trust, such ONEOK
Capital Trust is not in arrears on payments of Distributions on the Preferred
Securities issued by such ONEOK Capital Trust and no deferred Distributions are
accumulated and (D) such Securities are rated not less than BBB- by S&P or Baa3

                                       30
<PAGE>

by Moody's, or the equivalent by any other nationally recognized statistical
orating organization.  In the event the Company elects to shorten or extend the
Stated Maturity of the Securities of a particular series, it shall give notice
to the Trustee, no less than 30 and no more than 60 days prior to the
effectiveness thereof.  The Trustee shall give notice of such shortening or
extension to the Holders promptly upon receipt.

     Section 3.15   CUSIP Numbers.

     The Company in issuing the Securities may use "CUSIP" numbers (if then
generally in use), and, if so, the Trustee shall use "CUSIP" numbers in notices
of redemption as a convenience to Holders; provided that any such notice may
state that no representation is made as to the correctness of such numbers
either as printed on the Securities or as contained in any notice of a
redemption and that reliance may be placed only on the other identification
numbers printed on the Securities, and any such redemption shall not be affected
by any defect in or omission of such "CUSIP" numbers.

                                  ARTICLE IV

                          SATISFACTION AND DISCHARGE

     Section 4.1    Satisfaction and Discharge of Indenture.

     This Indenture shall, upon Company Request, cease to be of further effect
(except as to any surviving rights of registration of transfer or exchange of
Securities herein expressly provided for and as otherwise provided in this
Section 4.1) and the Trustee, on demand of and at the expense of the Company,
shall execute proper instruments acknowledging satisfaction and discharge of
this Indenture, when

     (1)   either

     (A)   all Securities theretofore authenticated and delivered (other than
(i) Securities which have been destroyed, lost or stolen and which have been
replaced or paid as provided in Section 3.6 and (ii) Securities for whose
payment money has theretofore been deposited in trust or segregated and held in
trust by the Company and thereafter repaid to the Company or discharged from
such trust, as provided in Section 10.3) have been delivered to the Trustee for
cancellation; or

     (B)   all such Securities not theretofore delivered to the Trustee for
cancellation

           (i)      have become due and payable, or

           (ii)     will become due and payable at their Stated Maturity within
                    one year of the date of deposit, or

           (iii)    are to be called for redemption within one year under
                    arrangements satisfactory to the Trustee for the giving of
                    notice of redemption by the Trustee in the name, and at the
                    expense, of the Company,

                                       31
<PAGE>

                    and the Company, in the case of Clause (B) (i), (ii) or
                    (iii) above, has deposited or caused to be deposited with
                    the Trustee as trust funds in trust for such purpose an
                    amount in the currency or currencies in which the Securities
                    of such series are payable sufficient to pay and discharge
                    the entire indebtedness on such Securities not theretofore
                    delivered to the Trustee for cancellation, for principal
                    (and premium, if any) and interest (including any Additional
                    Interest) to the date of such deposit (in the case of
                    Securities which have become due and payable) or to the
                    Stated Maturity or Redemption Date, as the case may be; and


     (2)   the Company has paid or caused to be paid all other sums payable
hereunder by the Company; and

     (3)   the Company has delivered to the Trustee an Officers' Certificate and
an Opinion of Counsel each stating that all conditions precedent herein provided
for relating to the satisfaction and discharge of this Indenture have been
complied with.

Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 6.7, the obligations of
the Trustee to any Authenticating Agent under Section 6.14 and, if money shall
have been deposited with the Trustee pursuant to subclause (B) of clause (1) of
this Section, the obligations of the Trustee under Section 4.2 and the last
paragraph of Section 10.3 shall survive.

     Section 4.2    Application of Trust Money.

     Subject to the provisions of the last paragraph of Section 10.3, all money
deposited with the Trustee pursuant to Section 4.1 shall be held in trust and
applied by the Trustee, in accordance with the provisions of the Securities and
this Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent) as the Trustee may
determine, to the Persons entitled thereto, of the principal (and premium, if
any) and interest for the payment of which such money or obligations have been
deposited with or received by the Trustee.

     Section 4.3    Satisfaction, Discharge and Defeasance of Securities of Any
Series.

     Unless otherwise provided in the Board Resolution adopted pursuant to
Section 3.1  or an indenture supplemental hereto establishing the terms of the
Securities of any series, the Company shall be deemed to have paid and
discharged the entire indebtedness on all the Outstanding Securities of any such
series and the Trustee, at the expense of the Company, shall execute proper
instruments acknowledging satisfaction and discharge of such indebtedness, when

     (1)   with respect to all Outstanding Securities of such series,

           (A)  the Company has irrevocably deposited or caused to be
     irrevocably deposited with the Trustee as trust funds in trust for such
     purpose an amount sufficient to pay and discharge the entire indebtedness
     on all Outstanding Securities of such series for principal (and premium, if
     any) and interest (including any Additional Interest) to the Stated
     Maturity or any Redemption Date as contemplated by the penultimate
     paragraph of this Section 4.3, as the case may be; or

                                       32
<PAGE>

           (B)  the Company has irrevocably deposited or caused to be
     irrevocably deposited with the Trustee as obligations in trust for such
     purpose an amount of trust funds as will, in the written opinion of
     independent public accountants delivered to the Trustee, together with
     predetermined and certain income to accrue thereon, without consideration
     of any reinvestment thereof, be sufficient to pay and discharge when due
     the entire indebtedness on all Outstanding Securities of such series for
     principal (and premium, if any) and interest (including any Additional
     Interest) to the Stated Maturity or any Redemption Date as contemplated by
     the penultimate paragraph of this Section 4.3, as the case may be;

     (2)   the Company has paid or caused to be paid all other sums payable with
respect to the Outstanding Securities of such series;

     (3)   the Company has delivered to the Trustee an Officers' Certificate and
     an Opinion of Counsel, each stating that all conditions precedent herein
     provided for relating to the satisfaction and discharge of the entire
     indebtedness on all Outstanding Securities of any such series have been
     complied with; and

     (4)   the Company has also delivered to the Trustee, together with such
     Officers' Certificate, either:

           (A) an instrument wherein the Company, notwithstanding the
     satisfaction and discharge of its indebtedness in respect of the
     Outstanding Securities of such series, shall assume the obligation (which
     shall be absolute and unconditional) to irrevocably deposit with the
     Trustee such additional sums of money, if any, or additional amounts
     (meeting the requirements of subsection (1) of this Section 4.3), if any,
     or any combination thereof, at such time or times, as shall be necessary,
     together with the money and/or amounts theretofore so deposited, to pay
     when due the principal of and interest due and to become due on such
     Outstanding Securities of such series or portions thereof, all in
     accordance with and subject to the provisions of this Section 4.3;
     provided, however, that such instrument may state that the obligation of
     the Company to make additional deposits as aforesaid shall be subject to
     the delivery to the Company by the Trustee of a notice asserting the
     deficiency accompanied by an opinion of an independent public accountant of
     nationally recognized standing, selected by the Trustee, showing the
     calculation thereof; or

           (B) an Opinion of Counsel, based on a change in law, to the effect
     that the Holders of such Outstanding Securities of such series, or portions
     of the principal amount thereof, will not recognize income, gain or loss
     for United States federal income tax purposes as a result of the
     satisfaction and discharge of the Company's indebtedness in respect thereof
     and will be subject to United States federal income tax on the same
     amounts, at the same times and in the same manner as if such satisfaction
     and discharge had not been effected.

     Any deposits with the Trustee referred to in Section 4.3(1) above shall be
irrevocable and shall be made under the terms of an escrow trust agreement in
form and substance reasonably satisfactory to the Trustee.  If any Outstanding
Securities of such series are to be redeemed prior to their Stated Maturity,
whether pursuant to any optional redemption provisions or in accordance with any
mandatory sinking fund requirement, the applicable escrow trust agreement shall
provide therefor and the Company shall make such arrangements as are
satisfactory to the Trustee for the giving of

                                       33
<PAGE>

notice of redemption by the Trustee in the name, and at the expense, of the
Company. If the Securities of such series are not to become due and payable at
their Stated Maturity or upon call for redemption within one (1) year of the
date of deposit, then the Company shall give, not later than the date of such
deposit, notice of such deposit to the Holders of Securities of such series.

     Upon satisfaction of the conditions set forth in this Section 4.3 with
respect to all the Outstanding Securities of any series, the terms and
conditions of such series, including the terms and conditions with respect
thereto set forth in this Indenture, shall no longer be binding upon, or
applicable to, the Company; provided, that the Company shall not be discharged
from any payment obligations in respect of Securities of such series which are
deemed not to be Outstanding under clause (iii) of the definition thereof if
such obligations continue to be valid obligations of the Company under
applicable law and provided further that the Company shall not be discharged
from its obligation to the Trustee under Section 6.7.


                                    ARTICLE V

                                    REMEDIES

     Section 5.1   Events of Default.

     "Event of Default," wherever used herein with respect to the Securities of
any series, means any one of the following events (whatever the reason for such
Event of Default and whether it shall be voluntary or involuntary or be effected
by operation of law or pursuant to any judgment, decree or order of any court or
any order, rule or regulation of any administrative or governmental body):

     (1)   the Company defaults in the payment of any interest upon any Security
of that series, including any Additional Interest in respect thereof, when it
becomes due and payable, and continuance of such default for a period of 30 days
(subject to the deferral of any due date in the case of an Extension Period); or

     (2)   the Company defaults in the payment of the principal of (or premium,
if any, on) any Security of that series at its Maturity; or

     (3)   the Company defaults in the performance, or breach, in any material
respect, of any of its covenants or warranties in this Indenture (other than a
covenant or warranty a default in the performance of which or the breach of
which is elsewhere in this Section specifically dealt with), and continuance of
such default or breach for a period of 90 days after there has been given, by
registered or certified mail, to the Company by the Trustee or to the Company
and the Trustee by the Holders of at least 25% in principal amount of the
Outstanding Securities of that series a written notice specifying such default
or breach and requiring it to be remedied; or

     (4)   the entry of a decree or order by a court having jurisdiction in the
premises adjudging the Company a bankrupt or insolvent, or approving as properly
filed a petition seeking reorganization, arrangement, adjustment or composition
of or in respect of the Company under any applicable United States federal or
state bankruptcy, insolvency, reorganization or other similar law, or appointing
a receiver, liquidator, assignee, trustee, sequestration (or other similar
official) of the Company or of

                                       34
<PAGE>

any substantial part of its property or ordering the winding up or liquidation
of its affairs, and the continuance of any such decree or order unstayed and in
effect for a period of 60 consecutive days; or

     (5)   the institution by the Company of proceedings to be adjudicated a
bankrupt or insolvent, or the consent by it to the institution of bankruptcy or
insolvency proceedings against it, or the filing by it of a petition or answer
or consent seeking reorganization or relief under any applicable United States
federal or state bankruptcy, insolvency, reorganization or other similar law, or
the consent by it to the filing of any such petition or to the appointment of a
receiver, liquidator, assignee, trustee, sequestration (or other similar
official) of the Company or of any substantial part of its property, or the
making by it of an assignment of the benefit of creditors, or the admission by
it in writing of its inability to pay its debts generally as they become due and
its willingness to be adjudicated a bankrupt, or the taking of corporate action
by the Company in furtherance of any such action; or

     (6)   any other Event of Default provided with respect to Securities of
that series.

     Section 5.2    Acceleration of Maturity; Rescission and Annulment.

     If an Event of Default (other than an Event of Default specified in Section
5.1(4) or 5.1(5)) with respect to Securities of any series at the time
Outstanding occurs and is continuing, then and in every such case the Trustee or
the Holders of not less than 25% in principal amount of the Outstanding
Securities of that series may declare the principal amount (or, if the
Securities of that series are Discount Securities, such portion of the principal
amount as may be specified in the terms of that series) of all the Securities of
that series to be due and payable immediately, by a notice in writing to the
Company (and to the Trustee if given by Holders), provided that, in the case of
the Securities of a series issued to a ONEOK Capital Trust, if, upon an Event of
Default, the Trustee or the Holders of not less than 25% in principal amount of
the Outstanding Securities of that series fail to declare the principal of all
the Securities of that series to be immediately due and payable, the holders of
at least 25% in aggregate liquidation amount of the corresponding series of
Preferred Securities then outstanding shall have such right by a notice in
writing to the Company and the Trustee; and upon any such declaration such
principal amount (or specified portion thereof) of and the accrued interest
(including any Additional Interest) on all the Securities of such series shall
become immediately due and payable.  Payment of principal and interest
(including any Additional Interest) on such Securities shall remain subordinated
to the extent provided in Article XIII notwithstanding that such amount shall
become immediately due and payable as herein provided.  If an Event of Default
specified in Section 5.1(4) or 5.1(5) with respect to Securities of any series
at the time Outstanding occurs, the principal amount of all the Securities of
that series (or, if the Securities of that series are Discount Securities, such
portion of the principal amount of such Securities as may be specified by the
terms of that series) shall automatically, and without any declaration or other
action on the part of the Trustee or any Holder, become immediately due and
payable.

     At any time after such a declaration of acceleration with respect to
Securities of any series has been made and before judgment or decree for payment
of the money due has been obtained by the Trustee as hereinafter in this Article
provided, the Holders of a majority in principal amount of the

                                       35
<PAGE>

Outstanding Securities of that series, by written notice to the Company and the
Trustee, may rescind and annul such declaration and its consequences if:

     (1)   the Company has paid or deposited with the Trustee a sum sufficient
to pay:

     (A)   all overdue installments of interest (including any Additional
Interest) on all Securities of that series,

     (B)   the principal of (and premium, if any, on) any Securities of that
series which have become due otherwise than by such declaration of acceleration
and interest thereon at the rate borne by the Securities, and

     (C)   all sums paid or advanced by the Trustee hereunder and the reasonable
compensation, expenses, disbursements and advances of the Trustee, its agents
and counsel; and

     (2)   all Events of Default with respect to Securities of that series,
other than the non-payment of the principal of Securities of that series which
has become due solely by such acceleration, have been cured or waived as
provided in Section 5.13.

     In the case of Securities of a series issued to a ONEOK Capital Trust, the
holders of  a majority in aggregate Liquidation Amount (as defined in the Trust
Agreement under which such ONEOK Capital Trust is formed) of the related series
of Preferred Securities issued by such ONEOK Capital Trust shall also have the
right to rescind and annul such declaration and its consequences by written
notice to the Company and the Trustee, subject to the satisfaction of the
conditions set forth in Clauses (1) and (2) above of this Section 5.2.

     No such rescission shall affect any subsequent default or impair any right
consequent thereon.

     Section 5.3  Collection of Indebtedness and Suits for Enforcement by
Trustee.

     The Company covenants that if:

     (1)   default is made in the payment of any installment of interest
(including any Additional Interest) on any Security when such interest becomes
due and payable and such default continues for a period of 30 days, or

     (2)   default is made in the payment of the principal of (and premium, if
any, on) any Security at the Maturity thereof the Company will, upon demand of
the Trustee, pay to the Trustee, for the benefit of the Holders of such
Securities, the whole amount then due and payable on such Securities for
principal, including any sinking fund payment or analogous obligations (and
premium, if any) and interest (including any Additional Interest); and, in
addition thereto, all amounts owing the Trustee under Section 6.7.

     If the Company fails to pay such amounts forthwith upon such demand, the
Trustee, in its own name and as trustee of an express trust, may institute a
judicial proceeding for the collection of the sums so due and unpaid, and may
prosecute such proceeding to judgment or final decree, and may enforce the same
against the Company or any other obligor upon the Securities and collect the

                                       36
<PAGE>

moneys adjudged or decreed to be payable in the manner provided by law out of
the property of the Company or any other obligor upon the Securities, wherever
situated.

     If an Event of Default with respect to Securities of any series occurs and
is continuing, the Trustee may in its discretion proceed to protect and enforce
its rights and the rights of the Holders of Securities of such series by such
appropriate judicial proceedings as the Trustee shall deem most effectual to
protect and enforce any such rights, whether for the specific enforcement of any
covenant or agreement in this Indenture or in aid of the exercise of any power
granted herein, or to enforce any other proper remedy.

     Section 5.4    Trustee May File Proofs of Claim.

     In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company of such other obligor or their
creditors, the Trustee (irrespective of whether the principal of the Securities
of any series shall then be due and payable as therein expressed or by
declaration or otherwise and irrespective of whether the Trustee shall have made
any demand on the Company for the payment of overdue principal (and premium, if
any) or interest (including any Additional Interest)) shall be entitled and
empowered, by intervention in such proceeding or otherwise,

     (i)   to file and prove a claim for the whole amount of principal (and
premium, if any) and interest (including any Additional Interest) owing and
unpaid in respect of the Securities and to file such other papers or documents
as may be necessary or advisable and to take any and all actions as are
authorized under the Trust Indenture Act in order to have the claims of the
Holders and any predecessor to the Trustee under Section 6.7 allowed in any such
judicial proceedings; and

     (ii)  in particular, the Trustee shall be authorized to collect and receive
any moneys or other property payable or deliverable on any such claims and to
distribute the same in accordance with Section 5.6; and

     (iii) any custodian, receiver, assignee, trustee, liquidator, sequesterator
(or other similar official) in any such judicial proceeding is hereby authorized
by each Holder to make such payments to the Trustee for distribution in
accordance with Section 5.6, and in the event that the Trustee shall consent to
the making of such payments directly to the Holders, to pay to the Trustee any
amount due to it and any predecessor Trustee under Section 6.7.

     Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder any plan of
reorganization, arrangement, adjustment or composition affecting the Securities
or the rights of any Holder thereof, or to authorize the Trustee to vote in
respect of the claim of any Holder in any such proceeding; provided, however,
that the Trustee may, on behalf of the Holders, vote for the election of a
trustee in bankruptcy or similar official and be a member of a creditors' or
other similar committee.

     Section 5.5    Trustee May Enforce Claim Without Possession of Securities.

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<PAGE>

     All rights of action and claims under this Indenture or the Securities may
be prosecuted and enforced by the Trustee without the possession of any of the
Securities or the production thereof in any proceeding relating thereto, and any
such proceeding instituted by the Trustee shall be brought in its own name as
trustee of an express trust, and any recovery of judgment shall, after provision
for the payment of all the amounts owing the Trustee and any predecessor Trustee
under Section 6.7, its agents and counsel, be for the ratable benefit of the
Holders of the Securities in respect of which such judgment has been recovered.

     Section 5.6    Application of Money Collected.

     Any money or property collected or to be applied by the Trustee with
respect to a series of Securities pursuant to this Article shall be applied in
the following order, at the date or dates fixed by the Trustee and, in case of
the distribution of such money or property on account of principal (or premium,
if any) or interest (including any Additional Interest), upon presentation of
the Securities and the notation thereon of the payment if only partially paid
and upon surrender thereof if fully paid:

     FIRST:    To the payment of all amounts due the Trustee and any predecessor
Trustee under Section 6.7;

     SECOND:   Subject to Article XIII, to the payment of the amounts then due
and unpaid upon such series of Securities for principal (and premium, if any)
and interest (including any Additional Interest), in respect of which or for the
benefit of which such money has been collected, ratably, without preference or
priority of any kind, according to the amounts due and payable on such series of
Securities for principal (and premium, if any) and interest (including any
Additional Interest), respectively; and

     THIRD:    The balance, if any, to the Person or Persons entitled thereto.

     Section 5.7    Limitation on Suits.

     No Holder of any Securities of any series shall have any right to institute
any proceeding, judicial or otherwise, with respect to this Indenture or for the
appointment of a receiver, assignee, trustee, liquidator, sequesterator (or
other similar official) or for any other remedy hereunder, unless:

     (1)   such Holder has previously given written notice to the Trustee of a
continuing Event of Default with respect to the Securities of that series;

     (2)   the Holders of not less than 25% in principal amount of the
Outstanding Securities of that series shall have made written request to the
Trustee to institute proceedings in respect of such Event of Default in its own
name as Trustee hereunder;

     (3)   such Holder or Holders have offered to the Trustee reasonable
indemnity against the costs, expenses and liabilities to be incurred in
compliance with such request;

     (4)   the Trustee for 60 days after its receipt of such notice, request and
offer of indemnity has failed to institute any such proceeding; and

                                       38
<PAGE>

     (5)   no direction inconsistent with such written request has been given to
the Trustee during such 60-day period by the Holders of a majority in principal
amount of the Outstanding Securities of that series; it being understood and
intended that no one or more of such Holders shall have any right in any manner
whatever by virtue of, or by availing itself of, any provision of this Indenture
to affect, disturb or prejudice the rights of any other Holders of Securities,
or to obtain or to seek to obtain priority or preference over any other of such
Holders or to enforce any right under this Indenture, except in the manner
herein provided and for the equal and ratable benefit of all such Holders.

     Section 5.8    Unconditional Right of Holders to Receive Principal, Premium
and Interest; Direct Action by Holders of Preferred Securities.

     Notwithstanding any other provision in this Indenture, the Holder of any
Security shall have the right which is absolute and unconditional to receive
payment of the principal of (and premium, if any) and (subject to Section 3.7)
interest (including any Additional Interest) on such Security on the respective
Stated Maturities expressed in such Security (or, in the case of redemption, on
the Redemption Date) and to institute suit for the enforcement of any such
payment, and such right shall not be impaired without the consent of such
Holder.  In the case of Securities of a series issued to a ONEOK Capital Trust,
any holder of the corresponding series of Preferred Securities issued by such
ONEOK Capital Trust shall have the right, upon the occurrence of an Event of
Default described in Section 5.1(1) or 5.1(2), to institute a suit directly
against the Company for enforcement of payment to such holder of principal of
(premium, if any) and (subject to Section 3.7) interest (including any
Additional Interest) on the Securities having a principal amount equal to the
aggregate Liquidation Amount (as defined in the Trust Agreement under which such
ONEOK Capital Trust is formed) of such Preferred Securities of the corresponding
series held by such holder.

     Section 5.9    Restoration of Rights and Remedies.

     If the Trustee, any Holder or any holder of Preferred Securities has
instituted any proceeding to enforce any right or remedy under this Indenture
and such proceeding has been discontinued or abandoned for any reason, or has
been determined adversely to the Trustee, such Holder or such holder of
Preferred Securities, then and in every such case the Company, the Trustee, the
Holders and such holder of Preferred Securities shall, subject to any
determination in such proceeding, be restored severally and respectively to
their former positions hereunder, and thereafter all rights and remedies of the
Trustee, the Holders and the holders of Preferred Securities shall continue as
though no such proceeding had been instituted.

     Section 5.10   Rights and Remedies Cumulative.

     Except as otherwise provided in the last paragraph of Section 3.6, no right
or remedy herein conferred upon or reserved to the Trustee or to the Holders is
intended to be exclusive of any other right or remedy, and every right and
remedy shall, to the extent permitted by law, be cumulative and in addition to
every other right and remedy given hereunder or now or hereafter existing at law
or in equity or otherwise.  The assertion or employment of any right or remedy
hereunder, or otherwise, shall not prevent the concurrent assertion or
employment of any other appropriate right or remedy.

     Section 5.11   Delay or Omission Not Waiver.

                                       39
<PAGE>

     No delay or omission of the Trustee, any Holder of any Security or any
holder of any Preferred Security to exercise any right or remedy accruing upon
any Event of Default shall impair any such right or remedy or constitute a
waiver of any such Event of Default or an acquiescence therein.

     Every right and remedy given by this Article or by law to the Trustee or to
the Holders and the right and remedy given to the holders of Preferred
Securities by Section 5.8 may be exercised from time to time, and as often as
may be deemed expedient, by the Trustee, the Holders or the holders of Preferred
Securities, as the case may be.

     Section 5.12   Control by Holders.

     The Holders of a majority in principal amount of the Outstanding Securities
of any series shall have the right to direct the time, method and place of
conducting any proceeding for any remedy available to the Trustee or exercising
any trust or power conferred on the Trustee, with respect to the Securities of
such series, provided that:

     (1)   such direction shall not be in conflict with any rule of law or with
this Indenture,

     (2)   the Trustee may take any other action deemed proper by the Trustee
which is not inconsistent with such direction, and

     (3)   subject to the provisions of Section 6.1, the Trustee shall have the
right to decline to follow such direction if a Responsible Officer or Officers
of the Trustee shall, in good faith, determine that the proceeding so directed
would be unjustly prejudicial to the Holders not joining in any such direction
or would involve the Trustee in personal liability.

     Section 5.13   Waiver of Past Defaults.

     The Holders of  a majority in principal amount of the Outstanding
Securities of any series and, in the case of any Securities of a series issued
to a ONEOK Capital Trust, the holders of  a majority in aggregate liquidation
amount Preferred Securities issued by such ONEOK Capital Trust may waive any
past default hereunder and its consequences with respect to such series except a
default:

     (1)   in the payment of the principal of (or premium, if any) or interest
(including any Additional Interest) on any Security of such series, or

     (2)   in respect of a covenant or provision hereof which under Article IX
cannot be modified or amended without the consent of the Holder of each
Outstanding Security of such series affected.

     Any such waiver shall be deemed to be on behalf of the Holders of all the
Securities of such series or, in the case of a waiver by holders of Preferred
Securities issued by such ONEOK Capital Trust, by all holders of Preferred
Securities issued by such ONEOK Capital Trust.

                                       40
<PAGE>

     Upon any such waiver, such default shall cease to exist, and any Event of
Default arising therefrom shall be deemed to have been cured, for every purpose
of this Indenture; but no such waiver shall extend to any subsequent or other
default or impair any right consequent thereon.

     Section 5.14   Undertaking for Costs.

     All parties to this Indenture agree, and each Holder of any Security by his
acceptance thereof shall be deemed to have agreed, that any court may in its
discretion require, in any suit for the enforcement of any right or remedy under
this Indenture, or in any suit against the Trustee for any action taken or
omitted by it as Trustee, the filing by any party litigant in such suit of an
undertaking to pay the costs of such suit, and that such court may in its
discretion assess reasonable costs, including reasonable attorneys' fees,
against any party litigant in such suit, having due regard to the merits and
good faith of the claims or defenses made by such party litigant; but the
provisions of this Section shall not apply to any suit instituted by the
Trustee, to any suit instituted by any Holder, or group of Holders, holding in
the aggregate more than 10% in principal amount of the Outstanding Securities of
any series, or to any suit instituted by any Holder for the enforcement of the
payment of the principal of (or premium, if any) or interest (including any
Additional Interest) on any Security on or after the respective Stated
Maturities expressed in such Security.

     Section 5.15   Waiver of Usury, Stay or Extension Laws.

     The Company covenants (to the extent that it may lawfully do so) that it
will not at any time insist upon, or plead, or in any manner whatsoever claim or
take the benefit or advantage of, any usury, stay or extension law wherever
enacted, now or at any time hereafter in force, which may affect the covenants
or the performance of this Indenture; and the Company (to the extent that it may
lawfully do so) hereby expressly waives any benefit or advantage of any such
law, and covenants that it will not hinder, delay or impede the execution of any
power herein granted to the Trustee, but will suffer and permit the execution of
every such power as though no such law had been enacted.


                                  ARTICLE VI

                                  THE TRUSTEE

     Section 6.1    Certain Duties and Responsibilities.

     (a)  Except during the continuance of an Event of Default,

          (1)  the Trustee undertakes to perform such duties and only such
duties as are specifically set forth in this Indenture, and no implied covenants
or obligations shall be read into this Indenture against the Trustee; and

          (2)  in the absence of bad faith on its part, the Trustee may
conclusively rely, as to the truth of the statements and the correctness of the
opinions expressed therein, upon certificates or opinions furnished to the
Trustee and conforming to the requirements of this Indenture; but in the case of
any such certificates or opinions which by any provisions hereof are
specifically required to

                                       41
<PAGE>

be furnished to the Trustee, the Trustee shall be under a duty to examine the
same to determine whether or not they conform to the requirements of this
Indenture.

     (b)  In case an Event of Default has occurred and is continuing, the
Trustee shall exercise such of the rights and powers vested in it by this
Indenture, and use the same degree of care and skill in their exercise, as a
prudent person would exercise or use under the circumstances in the conduct of
his own affairs.

     (c)  No provision of this Indenture shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent failure
to act, or its own willful misconduct except that:

          (1)  this Subsection shall not be construed to limit the effect of
Subsection (a) of this Section;

          (2)  the Trustee shall not be liable for any error of judgment made in
good faith by a Responsible Officer; unless it shall be proved that the Trustee
was negligent in ascertaining the pertinent facts; and

          (3)  the Trustee shall not be liable with respect to any action taken
or omitted to be taken by it in good faith in accordance with the direction of
Holders pursuant to Section 5.12 relating to the time, method and place of
conducting any proceeding for any remedy available to the Trustee, or exercising
any trust or power conferred upon the Trustee, under this Indenture with respect
to the Securities of such series.

     (d)  No provision of this Indenture shall require the Trustee to expend or
risk its own funds or otherwise incur any financial liability in the performance
of any of its duties hereunder, or in the exercise of any of its rights or
powers, if there shall be reasonable grounds for believing that repayment of
such funds or adequate indemnity against such risk or liability is not
reasonably assured to it.

     (e)  Whether or not therein expressly so provided, every provision of this
Indenture relating to the conduct or affecting the liability of or affording
protection to the Trustee shall be subject to the provisions of this Section.

     Section 6.2    Notice of Defaults.

     Within 90 days after actual knowledge by a Responsible Officer of the
Trustee of the occurrence of any default hereunder with respect to the
Securities of any series, the Trustee shall transmit by mail to all Holders of
Securities of such series, as their names and addresses appear in the Securities
Register, notice of such default, unless such default shall have been cured or
waived; provided, however, that, except in the case of a default in the payment
of the principal of (or premium, if any) or interest (including any Additional
Interest) on any Security of such series, the Trustee shall be protected in
withholding such notice if and so long as the board of directors, the executive
committee or a trust committee of directors and/or Responsible Officers of the
Trustee in good faith determines that the withholding of such notice is in the
interests of the Holders of Securities of such series; and provided, further,
that, in the case of any default of the character specified in Section 5.1(3),
no such notice to Holders of Securities of such series shall be given until

                                       42
<PAGE>

at least 30 days after the occurrence thereof. For the purpose of this Section,
the term "default" means any event which is, or after notice or lapse of time or
both would become, an Event of Default with respect to Securities of such
series.

     Section 6.3    Certain Rights of Trustee.

     Subject to the provisions of Section 6.1:

     (a)  the Trustee may rely and shall be protected in acting or refraining
from acting upon any resolution, certificate, statement, instrument, opinion,
report, notice, request, direction, consent, order, bond, debenture, Security or
other paper or document believed by it to be genuine and to have been signed or
presented by the proper party or parties;

     (b)  any request or direction of the Company mentioned herein shall be
sufficiently evidenced by a Company Request or Company Order and any resolution
of the Board of Directors may be sufficiently evidenced by a Board Resolution;

     (c)  whenever in the administration of this Indenture the Trustee shall
deem it desirable that a matter be proved or established prior to taking,
suffering or omitting any action hereunder, the Trustee (unless other evidence
be herein specifically prescribed) may, in the absence of bad faith on its part,
rely upon an Officers' Certificate;

     (d)  the Trustee may consult with counsel and the advice of such counsel or
any Opinion of Counsel shall be full and complete authorization and protection
in respect of any action taken, suffered or omitted by it hereunder in good
faith and in reliance thereon;

     (e)  the Trustee shall be under no obligation to exercise any of the rights
or powers vested in it by this Indenture at the request or direction of any of
the Holders pursuant to this Indenture, unless such Holders shall have offered
to the Trustee reasonable security or indemnity against the costs, expenses and
liabilities which might be incurred by it in compliance with such request or
direction;

     (f)  the Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, indenture,
Security or other paper or document, but the Trustee in its discretion may make
such inquiry or investigation into such facts or matters as it may see fit, and,
if the Trustee shall determine to make such inquiry or investigation, it shall
be entitled to examine the books, records and premises of the Company,
personally or by agent or attorney; and

     (g)  the Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed with due care by it
hereunder.

     Section 6.4    Not Responsible for Recitals or Issuance of Securities.

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<PAGE>

     The recitals contained herein and in the Securities, except the Trustee's
certificates of authentication, shall be taken as the statements of the Company,
and neither the Trustee nor any Authenticating Agent assumes any responsibility
for their correctness.  The Trustee makes no representations as to the validity
or sufficiency of this Indenture or of the Securities.  Neither the Trustee nor
any Authenticating Agent shall be accountable for the use or application by the
Company of the Securities or the proceeds thereof.

     Section 6.     May Hold Securities.

     The Trustee, any Authenticating Agent, any Paying Agent, any Securities
Registrar or any other agent of the Company, in its individual or any other
capacity, may become the owner or pledgee of Securities and, subject to Sections
6.8 and 6.13, may otherwise deal with the Company with the same rights it would
have if it were not Trustee, Authenticating Agent, Paying Agent, Securities
Registrar or such other agent.

     Section 6.6    Money Held in Trust.

     Money held by the Trustee in trust hereunder need not be segregated from
other funds except to the extent required by law.  The Trustee shall be under no
liability for interest on any money received by it hereunder except as otherwise
agreed with the Company.

     Section 6.7    Compensation and Reimbursement.

     The Company agrees:

     (1)  to pay to the Trustee from time to time reasonable compensation for
all services rendered by it hereunder in such amounts as the Company, and the
Trustee shall agree from time to time (which compensation shall not be limited
by any provision of law in regard to the compensation of a trustee of an express
trust);

     (2)  to reimburse the Trustee upon its request for all reasonable expenses,
disbursements and advances incurred or made by the Trustee in accordance with
any provision of this Indenture (including the reasonable compensation and the
expenses and disbursements of its agents and counsel), except any such expense,
disbursement or advance as may be attributable to its negligence or bad faith;
and

     (3)  to indemnify the Trustee for, and to hold it harmless against, any
loss, liability or expense (including the reasonable compensation and the
expenses and disbursements of its agents and counsel) incurred without
negligence or bad faith, arising out of or in connection with the acceptance or
administration of this trust or the performance of its duties hereunder,
including the costs and expenses of defending itself against any claim or
liability in connection with the exercise or performance of any of its powers or
duties hereunder.  This indemnification shall survive the termination of this
Indenture and the resignation or removal of the Trustee.

     To secure the Company's payment obligations in this Section, the Company,
and the Holders agree that the Trustee shall have a lien prior to the Securities
on all money or property held or collected by the Trustee.  Such lien shall
survive the satisfaction and discharge of this Indenture.

                                       44
<PAGE>

     When the Trustee incurs expenses or renders services after an Event of
Default specified in Section 5.1(4) or (5) occurs, the expenses and the
compensation for the services are intended to constitute expenses of
administration under the Bankruptcy Reform Act of 1978 or any successor statute.

     Section 6.8    Disqualification; Conflicting Interests.

     The Trustee for the Securities of any series issued hereunder shall be
subject to the provisions of Section 310(b) of the Trust Indenture Act.  Nothing
herein shall prevent the Trustee from filing with the Commission the application
referred to in the second to last paragraph of said Section 310(b).  Each Trust
Agreement and ONEOK Capital Guarantee are hereby excluded from the provision of
Section 310(b)(1) of the Trust Indenture Act.

     Section 6.9    Corporate Trustee Required; Eligibility.

     There shall at all times be a Trustee hereunder which shall be

     (a)  a corporation organized and doing business under the laws of the
United States of America or of any State or Territory or the District of
Columbia, authorized under such laws to exercise corporate trust powers and
subject to supervision or examination by United States federal, state,
territorial or District of Columbia authority, or

     (b)  a corporation or other Person organized and doing business under the
laws of a foreign government that is permitted to act as Trustee pursuant to a
rule, regulation or order of the Commission, authorized under such laws to
exercise corporate trust powers, and subject to supervision or examination by
authority of such foreign government or a political subdivision thereof
substantially equivalent to supervision or examination applicable to United
States institutional trustees, in either case having a combined capital and
surplus of at least $50,000,000, subject to supervision or examination by United
States federal or state authority. If such corporation publishes reports of
condition at least annually, pursuant to law or to the requirements of the
aforesaid supervising or examining authority, then, for the purposes of this
Section, the combined capital and surplus of such corporation shall be deemed to
be its combined capital and surplus as set forth in its most recent report of
condition so published. If at any time the Trustee shall cease to be eligible in
accordance with the provisions of this Section, it shall resign immediately in
the manner and with the effect hereinafter specified in this Article. Neither
the Company, nor any Person directly or indirectly controlling, controlled by or
under common control with the Company shall serve as Trustee for the Securities
of any series issued hereunder.

     Section 6.10   Resignation and Removal; Appointment of Successor.

     (a)  No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee under Section 6.11.

     (b)  The Trustee may resign at any time with respect to the Securities of
one or more series by giving written notice thereof to the Company.  If an
instrument of acceptance by a successor Trustee shall not have been delivered to
the Trustee within 30 days after the giving of such notice of

                                       45
<PAGE>

resignation, the resigning Trustee may petition any court of competent
jurisdiction for the appointment of a successor Trustee with respect to the
Securities of such series.

     (c)  The Trustee may be removed at any time with respect to the Securities
of any series by Act of the Holders of a majority in principal amount of the
Outstanding Securities of such series, delivered to the Trustee and to the
Company.

     (d)  If at any time:

          (1)  the Trustee shall fail to comply with Section 6.8 after written
request therefor by the Company, or by any Holder who has been a bona fide
Holder of a Security for at least six months, or

          (2)  the Trustee shall cease to be eligible under Section 6.9 and
shall fail to resign after written request therefor by the Company, or by any
such Holder, or

          (3)  the Trustee shall become incapable of acting or shall be adjudged
a bankrupt or insolvent or a receiver of the Trustee or of its property shall be
appointed or any public officer shall take charge or control of the Trustee or
of its property or affairs for the purpose of rehabilitation, conservation or
liquidation, then, in any such case, (i) the Company acting pursuant to the
authority of a Board Resolution, may remove the Trustee with respect to all
Securities, or (ii) subject to Section 5.14, any Holder who has been a bona fide
Holder of a Security for at least six months may, on behalf of himself and all
others similarly situated, petition any court of competent jurisdiction for the
removal of the Trustee with respect to all Securities and the appointment of a
successor Trustee or Trustees.

     (e)  If the Trustee shall resign, be removed or become incapable of acting,
or if a vacancy shall occur in the office of Trustee for any cause with respect
to the Securities of one or more series, the Company, by a Board Resolution,
shall promptly appoint a successor Trustee with respect to the Securities of
that or those series.  If, within one year after such resignation, removal or
incapability, or the occurrence of such vacancy, a successor Trustee with
respect to the Securities of any series shall be appointed by Act of the Holders
of a majority in principal amount of the Outstanding Securities of such series
delivered to the Company and the retiring Trustee, the successor Trustee so
appointed shall, forthwith upon its acceptance of such appointment, become the
successor Trustee with respect to the Securities of such series and supersede
the successor Trustee appointed by the Company.  If no successor Trustee with
respect to the Securities of any series shall have been so appointed by the
Company or the Holders and accepted appointment in the manner hereinafter
provided, any Holder who has been a bona fide Holder of a Security for at least
six months may, subject to Section 5.14, on behalf of himself and all others
similarly situated, petition any court of competent jurisdiction for the
appointment of a successor Trustee with respect to the Securities of such
series.

     (f)  The Company shall give notice of each resignation and each removal of
the Trustee with respect to the Securities of any series and each appointment of
a successor Trustee with respect to the Securities of any series by mailing
written notice of such event by first-class mail, postage prepaid, to the
Holders of Securities of such series as their names and addresses appear in the

                                       46
<PAGE>

Securities Register. Each notice shall include the name of the successor Trustee
with respect to the Securities of such series and the address of its Corporate
Trust Office.

     Section 6.1    Acceptance of Appointment by Successor.

     (a)  In case of the appointment hereunder of a successor Trustee with
respect to all Securities, every such successor Trustee so appointed shall
execute, acknowledge and deliver to the Company and to the retiring Trustee an
instrument accepting such appointment, and thereupon the resignation or removal
of the retiring Trustee shall become effective and such successor Trustee,
without any further act, deed or conveyance, shall become vested with all the
rights, powers, trusts and duties of the retiring Trustee; but, on the request
of the Company or the successor Trustee, such retiring Trustee shall, upon
payment of its charges, execute and deliver an instrument transferring to such
successor Trustee all the rights, powers and trusts of the retiring Trustee and
shall duly assign, transfer and deliver to such successor Trustee all property
and money held by such retiring Trustee hereunder.

     (b)  In case of the appointment hereunder of a successor Trustee with
respect to the Securities of one or more (but not all) series, the Company, the
retiring Trustee and each successor Trustee with respect to the Securities of
any series shall execute and deliver an indenture supplemental hereto wherein
each successor Trustee shall accept such appointment and which (1) shall contain
such provisions as shall be necessary or desirable to transfer and confirm to,
and to vest in, each successor Trustee all the rights, powers, trusts and duties
of the retiring Trustee with respect to the Securities of that or those series
to which the appointment of such successor Trustee relates, (2) if the retiring
Trustee is not retiring with respect to all Securities, shall contain such
provisions as shall be deemed necessary or desirable to confirm that all the
rights, powers, trusts and duties of the retiring Trustee with respect to the
Securities of that or those series as to which the retiring Trustee is not
retiring shall continue to be vested in the retiring Trustee, and (3) shall add
to or change any of the provisions of this Indenture as shall be necessary to
provide for or facilitate the administration of the trusts hereunder by more
than one Trustee, it being understood that nothing herein or in such
supplemental indenture shall constitute such Trustees co-trustees of the same
trust and that each such Trustee shall be trustee of a trust or trusts hereunder
separate and apart from any trust or trusts hereunder administered by any other
such Trustee; and upon the execution and delivery of such supplemental indenture
the resignation or removal of the retiring Trustee shall become effective to the
extent provided therein and each such successor Trustee, without any further
act, deed or conveyance, shall become vested with all the rights, powers,
trusts, and duties of the retiring Trustee with respect to the Securities of any
series to which the appointment of such successor Trustee relates; but, on
request of the Company or any successor Trustee, such retiring Trustee shall
duly assign, transfer and deliver to such successor Trustee all property and
money held by such retiring Trustee hereunder with respect to the Securities of
that or those series to which the appointment of such successor Trustee relates.

     (c)  Upon request of any such successor Trustee, the Company shall execute
any and all instruments for more fully and certainly vesting in and confirming
to such successor Trustee all rights, powers and trusts referred to in paragraph
(a) or (b) of this Section, as the case may be.

     (d)  No successor Trustee shall accept its appointment unless at the time
of such acceptance such successor Trustee shall be qualified and eligible under
this Article.

                                       47
<PAGE>

     Section 6.12   Merger, Conversion, Consolidation or Succession to Business.

     Any corporation into which the Trustee may be merged or converted or with
which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all of the corporate trust
business of the Trustee, shall be the successor of the Trustee hereunder,
provided such corporation shall be otherwise qualified and eligible under this
Article, without the execution or filing of any paper or any further act on the
part of any of the parties hereto.  In case any Securities shall have been
authenticated, but not delivered, by the Trustee then in office, any successor
by merger, conversion or consolidation to such authenticating Trustee may adopt
such authentication and deliver the Securities so authenticated, and in case any
Securities shall not have been authenticated, any successor to the Trustee may
authenticate such Securities either in the name of any predecessor Trustee or in
the name of such successor Trustee, and in all cases the certificate of
authentication shall have the full force which it is provided anywhere in the
Securities or in this Indenture that the certificate of the Trustee shall have.

     Section 6.13   Preferential Collection of Claims Against Company.

     If and when the Trustee shall be or become a creditor of the Company or any
other obligor upon the Securities, the Trustee shall be subject to the
provisions of the Trust Indenture Act regarding the collection of claims against
the Company or any such other obligor.

     Section 6.14   Appointment of Authenticating Agent.

     The Trustee may appoint an Authenticating Agent or Agents with respect to
one or more series of Securities which shall be authorized to act on behalf of
the Trustee to authenticate Securities of such series issued upon original issue
and upon exchange, registration of transfer or partial redemption thereof or
pursuant to Section 3.6, and Securities so authenticated shall be entitled to
the benefits of this Indenture and shall be valid and obligatory for all
purposes as if authenticated by the Trustee hereunder.  Wherever reference is
made in this Indenture to the authentication and delivery of Securities by the
Trustee or the Trustee's certificate of authentication, such reference shall be
deemed to include authentication and delivery on behalf of the Trustee by an
Authenticating Agent. Each Authenticating Agent shall be acceptable to the
Company shall at all times be a corporation organized and doing business under
the laws of the United States of America, or of any State or Territory or the
District of Columbia, authorized under such laws to act as Authenticating Agent,
having a combined capital and surplus of not less than $50,000,000, except for
Affiliates of the Trustee, and subject to supervision or examination by United
States federal or state authority.  If such Authenticating Agent publishes
reports of condition at least annually, pursuant to law or to the requirements
of said supervising or examining authority, then for the purposes of this
Section the combined capital and surplus of such Authenticating Agent shall be
deemed to be its combined capital and surplus as set forth in its most recent
report of condition so published.  If at any time an Authenticating Agent shall
cease to be eligible in accordance with the provisions of this Section, such
Authenticating Agent shall resign immediately in the manner and with the effect
specified in this Section.

     Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or

                                       48
<PAGE>

consolidation to which such Authenticating Agent shall be a party, or any
corporation succeeding to all or substantially all of the corporate trust
business of an Authenticating Agent shall be the successor Authenticating Agent
hereunder, provided such corporation shall be otherwise eligible under this
Section, without the execution or filing of any paper or any further act on the
part of the Trustee or the Authenticating Agent.

     An Authenticating Agent may resign at any time by giving written notice
thereof to the Trustee and the Company.  The Trustee may at any time terminate
the agency of an Authenticating Agent by giving written notice thereof to such
Authenticating Agent and the Company.  Upon receiving such a notice of
resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section, the Trustee may appoint a successor Authenticating
Agent which shall be acceptable to the Company and shall give notice of such
appointment in the manner provided in Section 1.6 to all Holders of Securities
of the series with respect to which such Authenticating Agent will serve.  Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provision of this Section.

     The Trustee agrees to pay to each Authenticating Agent from time to time
reasonable compensation for its services under this Section, and the Trustee
shall be entitled to be reimbursed for such payments, subject to the provisions
of Section 6.7.

     If an appointment with respect to one or more series is made pursuant to
this Section, the Securities of such series may have endorsed thereon, in
addition to the Trustee's certificate of authentication, an alternative
certificate of authentication in the following form:

     This is one of the Securities referred to in the within-mentioned
Indenture.



Dated:_______________________________


As Trustee


By:__________________________________
     As Authenticating Agent


By:__________________________________
     Authorized Officer


                                   ARTICLE VII

                                       49
<PAGE>

               HOLDER'S LISTS AND REPORTS BY TRUSTEE AND COMPANY

     Section 7.1    Company to Furnish Trustee Names and Addresses of Holders.

     The Company will furnish or cause to be furnished to the Trustee:

     (a)  semi-annually, not more than 15 days after January 15 and July 15 in
each year, a list, in such form as the Trustee may reasonably require, of the
names and addresses of the Holders as of such January 1 and July 1, and

     (b)  at such other times as the Trustee may request in writing, within 30
days after the receipt by the Company of any such request, a list of similar
form and content as of a date not more than 15 days prior to the time such list
is furnished, excluding from any such list names and addresses received by the
Trustee in its capacity as Securities Registrar.

     Section 7.2    Preservation of Information, Communications to Holders.

     (a)  The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the Trustee as provided in Section 7.1 and the names and
addresses of Holders received by the Trustee in its capacity as Securities
Registrar.  The Trustee may destroy any list furnished to it as provided in
Section 7.1 upon receipt of a new list so furnished.

     (b)  The rights of Holders to communicate with other Holders with respect
to their rights under this Indenture or under the Securities, and the
corresponding rights and privileges of the Trustee, shall be as provided in the
Trust Indenture Act.

     (c)  Every Holder of Securities, by receiving and holding the same, agrees
with the Company and the Trustee that none of the Company the Trustee or any
agent of either of them shall be held accountable by reason of the disclosure of
information as to the names and addresses of the Holders made pursuant to the
Trust Indenture Act.

     Section 7.2    Reports by Trustee.

     (a)  The Trustee shall transmit to Holders such reports concerning the
Trustee and its actions under this Indenture as may be required pursuant to the
Trust Indenture Act, at the times and in the manner provided pursuant thereto.

     (b)  Reports so required to be transmitted at stated intervals of not more
than 12 months shall be transmitted no later than 60 days following May 15 in
each calendar year, commencing after the first issuance of Securities under this
Indenture.

     (c)  A copy of each such report shall, at the time of such transmission to
Holders, be filed by the Trustee with each stock exchange upon which any
Securities are listed and also with the Commission.  The Company will notify the
Trustee when any Securities are listed on any stock exchange.

                                       50
<PAGE>

     Section 7.4    Reports by the Company.

     The Company shall file with the Trustee and with the Commission, and
transmit to Holders, such information, documents and other reports, and such
summaries thereof, as may be required pursuant to the Trust Indenture Act at the
times and in the manner provided in the Trust Indenture Act; provided that any
such information, documents or reports required to be filed with the Commission
pursuant to Section 13 or Section 15(d) of the Exchange Act shall be filed with
the Trustee within 15 days after the same is required to be filed with the
Commission.  Notwithstanding that the Company may not be required to remain
subject to the reporting requirements of Section 13 or 15(d) of the Exchange
Act, the Company shall continue to file with the Commission and provide the
Trustee with the annual reports and the information, documents and other reports
which are specified in Sections 13 and 15(d) of the Exchange Act.  The Company
also shall comply with the other provisions of Section 314(a) of the Trust
Indenture Act.


                                 ARTICLE VIII

             CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

     Section 8.1    Company May Consolidate, Etc., Only on Certain Terms.

     The Company shall not consolidate with or merge into any other Person or
convey, transfer or lease its properties and assets substantially as an entirety
to any Person, and no Person shall consolidate with or merge into the Company or
convey, transfer or lease its properties and assets substantially as an entirety
to the Company, unless:

     (1)  in case the Company shall consolidate with or merge into another
Person or convey, transfer or lease its properties and assets substantially as
an entirety to any Person, the corporation formed by such consolidation or into
which the Company is merged or the Person which acquires by conveyance or
transfer, or which leases, the properties and assets of the Company
substantially as an entirety shall be a corporation, partnership or trust and
shall expressly assume, by an indenture supplemental hereto, executed and
delivered to the Trustee, in form satisfactory to the Trustee, the due and
punctual payment of the principal of (and premium, if any) and interest
(including any Additional Interest) on all the Securities and the performance of
every covenant of this Indenture on the part of the Company to be performed or
observed;

     (2)  immediately after giving effect to such transaction, no Event of
Default, and no event which, after notice or lapse of time, or both, would
become an Event of Default, shall have happened and be continuing;

     (3)  in the case of the Securities of a series issued to a ONEOK Capital
Trust, such consolidation, merger, conveyance, transfer or lease is permitted
under the related Trust Agreement and ONEOK Capital Guarantee and does not give
rise to any breach or violation of the related Trust Agreement or ONEOK Capital
Guarantee; and

     (4)  the Company has delivered to the Trustee an Officers' Certificate and
an Opinion of Counsel, each stating that such consolidation, merger, conveyance,
transfer or lease and any such

                                       51
<PAGE>

supplemental indenture comply with this Article and that all conditions
precedent herein provided relating to such transaction have been complied with;
and the Trustee, subject to Section 6.1, may rely upon such Officers'
Certificate and Opinion of Counsel as conclusive evidence that such transaction
complies with this Section 8.1.

     Section 8.2    Successor Corporation Substituted.

     Upon any consolidation or merger by the Company with or into any other
Person, or any conveyance, transfer or lease by the Company of its properties
and assets substantially as an entirety to any Person in accordance with Section
8.1, the successor corporation formed by such consolidation or into which the
Company is merged or to which such conveyance, transfer or lease is made shall
succeed to, and be substituted for, and may exercise every right and power of,
the Company, under this Indenture with the same effect as if such successor
Person had been named as the Company herein; and in the event of any such
conveyance, transfer or lease the Company, shall be discharged from all
obligations and covenants under the Indenture and the Securities and may be
dissolved and liquidated.

     Such successor Person may cause to be signed, and may issue either in its
own name or in the name of the Company any or all of the Securities issuable
hereunder which theretofore shall not have been signed by the Company and
delivered to the Trustee; and, upon the order of such successor Person instead
of the Company and subject to all the terms, conditions and limitations in this
Indenture prescribed, the Trustee shall authenticate and shall deliver any
Securities which previously shall have been signed and delivered by the officers
of the Company to the Trustee for authentication pursuant to such provisions and
any Securities which such successor Person thereafter shall cause to be signed
and delivered to the Trustee on its behalf for the purpose pursuant to such
provisions.  All the Securities so issued shall in all respects have the same
legal rank and benefit under this Indenture as the Securities theretofore or
thereafter issued in accordance with the terms of this Indenture as though all
of such Securities had been issued at the date of the execution hereof.

     In case of any such consolidation, merger, sale, conveyance or lease, such
changes in phraseology and form may be made in the Securities thereafter to be
issued as may be appropriate.


                                  ARTICLE IX

                            SUPPLEMENTAL INDENTURES

     Section 9.1    Supplemental Indentures without Consent of Holders.

     Without the consent of any Holders, the Company, when authorized by a Board
Resolution, and the Trustee, at any time and from time to time, may enter into
one or more indentures supplemental hereto, in form satisfactory to the Trustee,
for any of the following purposes:

     (1)  to evidence the succession of another Person to the Company, and the
assumption by any such successor of the covenants of the Company herein and in
the Securities contained; or

                                       52
<PAGE>

     (2)  to convey, transfer, assign, mortgage or pledge any property to or
with the Trustee or to surrender any right or power herein conferred upon the
Company; or

     (3)  to establish the form or terms of Securities of any series as
permitted by Sections 2.1 or 3.1; or

     (4)  to add to the covenants of the Company for the benefit of the Holders
of all or any series of Securities (and if such covenants are to be for the
benefit of less than all series of Securities, stating that such covenants are
expressly being included solely for the benefit of such series) or to surrender
any right or power herein conferred upon the Company; or

     (5)  to add any additional Events of Default for the benefit of the Holders
of all or any series of Securities (and if such additional Events of Default are
to be for the benefit of less than all series of Securities, stating that such
additional Events of Default are expressly being included solely for the benefit
of such series); or

     (6)  to change or eliminate any of the provisions of this Indenture,
provided that any such change or elimination shall become effective only when
there is no Security Outstanding of any series created prior to the execution of
such supplemental indenture which is entitled to the benefit of such provision;
or

     (7)  to cure any ambiguity, to correct or supplement any provision herein
which may be defective or inconsistent with any other provision herein, or to
make any other provisions with respect to matters or questions arising under
this Indenture, provided that such action pursuant to this clause (7) shall not
adversely affect the interest of the Holders of Securities of any series in any
material respect or, in the case of the Securities of a series issued to a ONEOK
Capital Trust and for so long as any of the corresponding series of Preferred
Securities issued by such ONEOK Capital Trust shall remain outstanding, the
holders of such Preferred Securities; or

     (8)  to evidence and provide for the acceptance of appointment hereunder by
a successor Trustee with respect to the Securities of one or more series and to
add to or change any of the provisions of this Indenture as shall be necessary
to provide for or facilitate the administration of the trusts hereunder by more
than one Trustee, pursuant to the requirements of Section 6.11(b); or

     (9)  to comply with the requirements of the Commission in order to effect
or maintain the qualification of this Indenture under the Trust Indenture Act.

     Section 9.2    Supplemental Indentures with Consent of Holders.

     With the consent of the Holders of not less than a majority in principal
amount of the Outstanding Securities of each series affected by such
supplemental indenture, by Act of said Holders delivered to the Company and the
Trustee, the Company, when authorized by a Board Resolution, and the Trustee may
enter into an indenture or indentures supplemental hereto for the purpose of
adding any provisions to or changing in any manner or eliminating any of the
provisions of this Indenture or of modifying in any manner the rights of the
Holders of Securities of such series under this Indenture; provided, however,
that no such supplemental indenture shall, without the consent of the Holder of
each Outstanding Security affected thereby,

                                       53
<PAGE>

     (1)  except to the extent permitted by Section 3.11 or as otherwise
specified as contemplated by Section 2.1 or Section 3.1 with respect to the
deferral of the payment of interest on the Securities of any series, change the
Stated Maturity of the principal of, or any installment of interest (including
any Additional Interest) on, any Security, or reduce the principal amount
thereof or the rate of interest thereon or reduce any premium payable upon the
redemption thereof; or reduce the amount of principal of a Discount Security
that would be due and payable upon a declaration of acceleration of the Maturity
thereof pursuant to Section 5.2, or change the place of payment where, or the
coin or currency in which, any Security or interest thereon is payable, or
impair the right to institute suit for the enforcement of any such payment on or
after the Stated Maturity thereof (or, in the case of redemption, on or after
the Redemption Date), or

     (2)  reduce the percentage in principal amount of the Outstanding
Securities of any series, the consent of whose Holders is required for any such
supplemental indenture, or the consent of whose Holders is required for any
waiver of compliance with certain provisions of this Indenture or certain
defaults hereunder and their consequences provided for in this Indenture, or

     (3)  modify any of the provisions of this Section, Section 5.13 or Section
10.5, except to increase any such percentage or to provide that certain other
provisions of this Indenture cannot be modified or waived without the consent of
the Holder of each Security affected thereby; or

     (4)  modify the provisions in Article XIII of this Indenture with respect
to the subordination of Outstanding Securities of any series in a manner adverse
to the Holders thereof;

provided, further, that, in the case of the Securities of a series issued to a
ONEOK Capital Trust, so long as any of the corresponding series of Preferred
Securities issued by such ONEOK Capital Trust remains outstanding, (i) no such
amendment shall be made that adversely affects the holders of such Preferred
Securities in any material respect, and no termination of this Indenture shall
occur, and no waiver of any Event of Default or compliance with any covenant
under this Indenture shall be effective, without the prior consent of the
holders of a majority of the aggregate liquidation preference of such Preferred
Securities then outstanding unless and until the principal (and premium, if any)
of the Securities of such series and all accrued and, subject to Section 3.7,
unpaid interest (including any Additional Interest) thereon have been paid in
full and (ii) no amendment shall be made to Section 5.8 of this Indenture that
would impair the rights of the holders of Preferred Securities provided therein
without the prior consent of the holders of each Preferred Security then
outstanding of such series unless and until the principal (and premium, if any)
of the Securities of such series and all accrued and (subject to Section 3.7)
unpaid interest (including any Additional Interest) thereon have been paid in
full.

     A supplemental indenture that changes or eliminates any covenant or other
provision of this Indenture that has expressly been included solely for the
benefit of one or more particular series of Securities or Preferred Securities,
or which modifies the rights of the Holders of Securities or holders of
Preferred Securities of such series with respect to such covenant or other
provision, shall be deemed not to affect the rights under this Indenture of the
Holders of Securities or holders of Preferred Securities of any other series.

                                       54
<PAGE>

     It shall not be necessary for any Act of Holders under this Section to
approve the particular form of any proposed supplemental indenture, but it shall
be sufficient if such Act shall approve the substance thereof.

     Section 9.3    Execution of Supplemental Indentures.

     In executing or accepting the additional trusts created by any supplemental
indenture permitted by this Article or the modifications thereby of the trusts
created by this Indenture, the Trustee shall be entitled to receive, and
(subject to Section 6.1) shall be fully protected in relying upon, an Officers'
Certificate and an Opinion of Counsel of the Company stating that the execution
of such supplemental indenture is authorized or permitted by this Indenture, and
that all conditions precedent have been complied with.  The Trustee may, but
shall not be obligated to, enter into any such supplemental indenture which
affects the Trustee's own rights, duties or immunities under this Indenture or
otherwise.

     Section 9.4    Effect of Supplemental Indentures.

     Upon the execution of any supplemental indenture under this Article, this
Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Securities theretofore or thereafter authenticated and delivered hereunder
shall be bound thereby.

     Section 9.5    Conformity with Trust Indenture Act.

     Every supplemental indenture executed pursuant to this Article shall
conform to the requirements of the Trust Indenture Act as then in effect.

     Section 9.6    Reference in Securities to Supplemental Indentures.

     Securities authenticated and delivered after the execution of any
supplemental indenture pursuant to this Article may, and shall if required by
the Company, bear a notation in form approved by the Company  as to any matter
provided for in such supplemental indenture.  If the Company shall so determine,
new Securities of any series so modified as to conform, in the opinion of the
Company, to any such supplemental indenture may be prepared and executed by the
Company and authenticated and delivered by the Trustee in exchange for
Outstanding Securities of such series.


                                   ARTICLE X

                                   COVENANTS

     Section 10.1   Payment of Principal, Premium and Interest.

     The Company covenants and agrees for the benefit of the Holders of each
series of Securities that it will duly and punctually pay the principal of (and
premium, if any) and interest and any other amounts payable on the Securities of
that series in accordance with the terms of such Securities and this Indenture.
Whenever in this Indenture or the Securities there is a reference in any context
to the

                                       55
<PAGE>

payment of interest on the Securities, such mention shall be deemed to include
payments of Additional Interest to the extent that Additional Interest is
payable on the Securities. Express mention of the payment of Additional Interest
(if applicable) in any provisions hereof shall not be construed as excluding
Additional Interest in those provisions hereof where such express mention is not
made.

     Section 10.2   Maintenance of Office or Agency.

     The Company will maintain in each Place of Payment for any series of
Securities, an office or agency where Securities of that series may be presented
or surrendered for payment and an office or agency where Securities of that
series may be surrendered for transfer or exchange and where notices and demands
to or upon the Company in respect of the Securities of that series and this
Indenture may be served.  The Company initially appoints the Trustee, acting
through its Corporate Trust Office, as its agent for said purposes.  The Company
will give prompt written notice to the Trustee of any change in the location of
any such office or agency.  If at any time the Company shall fail to maintain
such office or agency or shall fail to furnish the Trustee with the address
thereof; such presentations, surrenders, notices and demands may be made or
served at the Corporate Trust Office of the Trustee, and the Company hereby
appoints the Trustee as its agent to receive all such presentations, surrenders,
notices and demands.

     The Company may also from time to time designate one or more other offices
or agencies where the Securities may be presented or surrendered for any or all
of such purposes, and may from time to time rescind such designations; provided,
however, that no such designation or rescission shall in any manner relieve the
Company of its obligation to maintain an office or agency in each Place of
Payment for Securities of any series for such purposes.  The Company will give
prompt written notice to the Trustee of any such designation and any change in
the location of any such office or agency.

     Section 10.3   Money or Security Payments to be Held in Trust.

     If the Company shall at any time act as its own Paying Agent with respect
to any series of Securities, it will, on or before each due date of the
principal of (and premium, if any) or interest on any of the Securities of such
series, segregate and hold in trust for the benefit of the Persons entitled
thereto a sum sufficient to pay the principal (and premium, if any) or interest
so becoming due until such sums shall be paid to such Persons or otherwise
disposed of as herein provided, and will promptly notify the Trustee of its
failure so to act.

     Whenever the Company shall have one or more Paying Agents, it will, prior
to 10:00 a.m. New York City time on each due date of the principal of or
interest on any Securities, deposit with a Paying Agent a sum sufficient to pay
the principal (and premium, if any) or interest so becoming due, such sum to be
held in trust for the benefit of the Persons entitled to such principal and
premium (if any) or interest, and (unless such Paying Agent is the Trustee) the
Company will promptly notify the Trustee of its failure so to act.

     The Company will cause each Paying Agent other than the Trustee to execute
and deliver to the Trustee an instrument in which such Paying Agent shall agree
with the Trustee, subject to the provisions of this Section, that such Paying
Agent will:

                                       56
<PAGE>

     (1)  hold all sums held by it for the payment of the principal of (and
premium, if any) or interest on Securities in trust for the benefit of the
Persons entitled thereto until such sums shall be paid to such Persons or
otherwise disposed of as herein provided;

     (2)  give the Trustee notice of any default by the Company (or any other
obligor upon the Securities) in the making of any payment of principal (and
premium, if any) or interest;

     (3)  at any time during the continuance of any such default, upon the
written request of the Trustee, forthwith pay to the Trustee all sums so held in
trust by such Paying Agent; and

     (4)  comply with the provisions of the Trust Indenture Act applicable to it
as a Paying Agent.

     The Company may at any time, for the purpose of obtaining the satisfaction
and discharge of this Indenture or for any other purpose, pay, or by Company
Order direct any Paying Agent to pay, to the Trustee all sums held in trust by
the Company or such Paying Agent, such sums to be held by the Trustee upon the
same trusts as those upon which such sums were held by the Company or such
Paying Agent; and, upon such payment by any Paying Agent to the Trustee, such
Paying Agent shall be released from all further liability with respect to such
money.

     Any money deposited with the Trustee or any Paying Agent, or then held by
the Company, in trust for the payment of the principal of (and premium, if any)
or interest on any Security and remaining unclaimed for two years after such
principal (and premium, if any) or interest has become due and payable shall
(unless otherwise required by mandatory provision of applicable escheat or
abandoned or unclaimed property law) be paid on Company Request to the Company,
or (if then held by the Company) shall (unless otherwise required by mandatory
provision of applicable escheat or abandoned or unclaimed property law) be
discharged from such trust; and the Holder of such Security shall thereafter, as
an unsecured general creditor, look only to the Company for payment thereof; and
all liability of the Trustee or such Paying Agent with respect to such trust
money, and all liability of the Company as trustee thereof; shall thereupon
cease; provided, however, that the Trustee or such Paying Agent, before being
required to make any such repayment, may at the expense of the Company cause to
be published once, in a newspaper published in the English language, customarily
published on each Business Day and of general circulation in the Borough of
Manhattan, The City of New York, notice that such money remains unclaimed and
that, after a date specified therein, which shall not be less than 30 days from
the date of such publication, any unclaimed balance of such money then remaining
will be repaid to the Company.

     Section 10.4   Statement as to Compliance.

     The Company shall deliver to the Trustee, within 120 days after the end of
each calendar year ending after the date hereof; an Officers' Certificate
complying with Section 314(a)(4) of the Trust Indenture Act and covering the
preceding calendar year, stating whether or not to the best knowledge of the
signers thereof the Company is in default in the performance, observance or
fulfillment of or compliance with any of the terms, provisions, covenants and
conditions of this Indenture, and if the Company shall be in default, specifying
all such defaults and the nature and status thereof of which they may have
knowledge.  For the purpose of this Section 10.4, compliance shall be determined

                                       57
<PAGE>

without regard to any grace period or requirement of notice provided pursuant to
the terms of this Indenture.

     Section 10.5   Waiver of Certain Covenants.

     The Company may omit in any particular instance to comply with any covenant
or condition provided pursuant to Section 3.1, 9.1(3) or 9.1(4) with respect to
the Securities of any series, if before or after the time for such compliance
the Holders of at least a majority in principal amount of the Outstanding
Securities of such series shall, by Act of such Holders, either waive such
compliance in such instance or generally waive compliance with such covenant or
condition, but no such waiver shall extend to or affect such covenant or
condition except to the extent so expressly waived, and, until such waiver shall
become effective, the obligations of the Company in respect of any such covenant
or condition shall remain in full force and effect.

     Section 10.6   Additional Sums.

     In the case of the Securities of a series issued to a ONEOK Capital Trust,
so long as no Event of Default has occurred and is continuing and except as
otherwise specified as contemplated by Section 2.1 or Section 3.1, in the event
that (i) a ONEOK Capital Trust is the Holder of all of the Outstanding
Securities of such series, (ii) a Tax Event in respect of such ONEOK Capital
Trust shall have occurred and be continuing and (iii) the Company shall not have
(A) redeemed the Securities of such series pursuant to Section 11.7(b) or (B)
terminated such ONEOK Capital Trust pursuant to Section 9.2(b) of the related
Trust Agreement, the Company shall pay to such ONEOK Capital Trust (and its
permitted successors or assigns under the related Trust Agreement) for so long
as such ONEOK Capital Trust (or its permitted successor or assignee) is the
registered holder of any Securities of such series, such additional amounts as
may be necessary in order that the amount of Distributions (including any
Additional Amounts (as defined in such Trust Agreement)) then due and payable by
such ONEOK Capital Trust on the related Preferred Securities and Common
Securities that at any time remain outstanding in accordance with the terms
thereof shall not be reduced as a result of any Additional Taxes (the
"Additional Sums").  Whenever in this Indenture or the Securities there is a
reference in any context to the payment of principal of, premium, if any, or
interest on the Securities, such mention shall be deemed to include mention of
the payments of the Additional Sums provided for in this paragraph to the extent
that, in such context, Additional Sums are, were or would be payable in respect
thereof pursuant to the provisions of this paragraph and express mention of the
payment of Additional Sums (if applicable) in any provisions hereof shall not be
construed as excluding Additional Sums in those provisions hereof where such
express mention is not made; provided, however, that the deferral of the payment
of interest pursuant to Section 3.11 or the Securities shall not defer the
payment of any Additional Sums that may be due and payable.

     Section 10.7   Additional Covenants.

     The Company covenants and agrees with each Holder of Securities of each
series that it shall not, (a) declare or pay any dividends or distributions on,
or redeem purchase, acquire or make a liquidation payment with respect to, any
shares of the its capital stock, or (b) make any payment of principal of or
interest or premium, if any, on or repay, repurchase or redeem any debt
securities issued by it that rank pari passu with or junior in interest to the
Securities of such series or make any guarantee payments with respect to any
guarantee by the Company of debt securities of any

                                       58
<PAGE>

Subsidiary of the Company if such guarantee ranks pari passu with or junior in
interest to the Securities (other than (a) dividends or distributions in Common
Stock, (b) any declaration of a dividend in connection with the implementation
of a Rights Plan, the issuance of any rights, of any Common Stock or any class
or series of preferred stock of the Company or of any other property under any
Rights Plan or the repurchase of any rights distributed pursuant to a Rights
Plan, (c) payments under any ONEOK Capital Guarantee, and (d) purchases of
Common Stock related to the issuance of Common Stock under any of the Company's
benefit plans for its directors, officers or employees), if at such time (i)
there shall have occurred any event of which the Company has actual knowledge
that (A) with the giving of notice or the lapse of time or both, would
constitute an Event of Default with respect to the Securities of such series and
(B) in respect of which the Company shall have not taken reasonable steps to
cure, (ii) if the Securities of such series are held by a ONEOK Capital Trust,
the Company shall be in default with respect to its payment of any obligations
under the ONEOK Capital Guarantee relating to the Preferred Securities issued by
such ONEOK Capital Trust or (iii) the Company shall have given notice of its
election to begin an Extension Period with respect to the Securities of such
series as provided herein and shall not have rescinded such notice, or such
Extension Period, or any extension thereof, shall be continuing.

     The Company also covenants with each Holder of Securities of a series
issued to a ONEOK Capital Trust (i) to maintain directly or indirectly 100%
ownership of the Common Securities of such ONEOK Capital Trust; provided,
however, that any permitted successor of the Company hereunder may succeed to
the Company's ownership of such Common Securities, (ii) not to voluntarily
terminate, wind-up or liquidate such ONEOK Capital Trust, except (a) in
connection with a distribution of the Securities of such series to the holders
of Preferred Securities in liquidation of such ONEOK Capital Trust or (b) in
connection with certain mergers, consolidations or amalgamations permitted by
the related Trust Agreement and (iii) to use its reasonable efforts, consistent
with the terms and provisions of such Trust Agreement, to cause such ONEOK
Capital Trust to remain classified as a grantor trust and not an association
taxable as a corporation for United States federal income tax purposes.


                                  ARTICLE XI

                           REDEMPTION OF SECURITIES

     Section 11.1   Applicability of This Article.

     Redemption of Securities of any series (whether by operation of a sinking
fund or otherwise) as permitted or required by any form of Security issued
pursuant to this Indenture shall be made in accordance with such form of
Security and this Article; provided, however, that if any provision of any such
form of Security shall conflict with any provision of this Article, the
provision of such form of Security shall govern.  Except as otherwise set forth
in the form of Security of a particular series, each Security of such series
which is redeemed in part shall be subject to redemption only in the amount of
$25 or integral multiples thereof.

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     Section 11.2   Election to Redeem; Notice to Trustee.

     The election of the Company to redeem any Securities shall be evidenced by
or pursuant to a Board Resolution.  In case of any redemption at the election of
the Company of less than all of the Securities of any particular series and
having the same terms, the Company shall, not less than 30 nor more than 60 days
prior to the Redemption Date (unless a shorter notice shall be satisfactory to
the Trustee), notify the Trustee of such date and of the principal amount of
Securities of that series to be redeemed.  In the case of any redemption of
Securities prior to the expiration of any restriction on such redemption
provided in the terms of such Securities, the Company shall furnish the Trustee
with an Officers' Certificate and an Opinion of Counsel evidencing compliance
with such restriction.

     Section 11.3   Selection of Securities to be Redeemed.

     If less than all the Securities of any series are to be redeemed (unless
all the Securities of such series and of a specified tenor are to be redeemed or
unless such redemption affects only a single Security), the particular
Securities to be redeemed shall be selected not more than 60 days prior to the
Redemption Date by the Trustee, from the Outstanding Securities of such series
not previously called for redemption, by such method as the Trustee shall deem
fair and appropriate and which may provide for the selection for redemption of a
portion of the principal amount of any Security of such series, provided that
the unredeemed portion of the principal amount of any Security shall be in an
authorized denomination (which shall not be less than the minimum authorized
denomination) for such Security.  If less than all the Securities of such series
and of a specified tenor are to be redeemed (unless such redemption affects only
a single Security), the particular Securities to be redeemed shall be selected
not more than 60 days prior to the Redemption Date by the Trustee, from the
Outstanding Securities of such series and specified tenor not previously called
for redemption in accordance with the preceding sentence.

     The Trustee shall promptly notify the Company in writing of the Securities
selected for partial redemption and the principal amount thereof to be redeemed.
For all purposes of this Indenture, unless the context otherwise requires, all
provisions relating to the redemption of Securities shall relate, in the case of
any Security redeemed or to be redeemed only in part, to the portion of the
principal amount of such Security which has been or is to be redeemed.  If the
Company shall so direct, Securities registered in the name of the Company, any
Affiliate or any Subsidiary thereof shall not be included in the Securities
selected for redemption.

     Section 11.4   Notice of Redemption.

     Notice of redemption shall be given by first-class mail, postage prepaid,
mailed not later than the thirtieth day, and not earlier than the sixtieth day,
prior to the Redemption Date, to each Holder of Securities to be redeemed, at
the address of such Holder as it appears in the Securities Register.

     With respect to Securities of each series to be redeemed, each notice of
redemption shall state:

     (a)  the Redemption Date;

     (b)  the Redemption Price;

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     (c)  if less than all Outstanding Securities of such particular series and
having the same terms are to be redeemed, the identification (and, in the case
of partial redemption, the respective principal amounts) of the particular
Securities to be redeemed;

     (d)  that on the Redemption Date, the Redemption Price will become due and
payable upon each such Security or portion thereof; and that interest thereon,
if any, shall cease to accrue on and after said date;

     (e)  the place or places where such Securities are to be surrendered for
payment of the Redemption Price; and

     (f)  that the redemption is for a sinking fund, if such is the case.

     Notice of redemption of Securities to be redeemed at the election of the
Company shall be given by the Company or, at the Company's request, by the
Trustee in the name and at the expense of the Company and shall not be
revocable.  The notice if mailed in the manner herein provided shall be
conclusively presumed to have been duly given, whether or not the Holder
receives such notice. In any case, a failure to give such notice by mail or any
defect in the notice to the Holder of any Security designated for redemption as
a whole or in part shall not affect the validity of the proceedings for the
redemption of any other Security.

     Section 11.5  Deposit of Redemption Price.

     Prior to 10:00 a.m.  New York City time on the Redemption Date specified in
the notice of redemption given as provided in Section 11.4, the Company will
deposit with the Trustee or with one or more Paying Agents (or if the Company is
acting as its own Paying Agent, the Company will segregate and hold in trust as
provided in Section 10.3) an amount of money sufficient to pay the Redemption
Price of; and any accrued interest (including Additional Interest) on, all the
Securities which are to be redeemed on that date.

     Section 11.6  Payment of Securities Called for Redemption.

     If any notice of redemption has been given as provided in Section 11.4, the
Securities or portion of Securities with respect to which such notice has been
given shall become due and payable on the date and at the place or places stated
in such notice at the applicable Redemption Price.  On presentation and
surrender of such Securities at a Place of Payment in said notice specified, the
said securities or the specified portions thereof shall be paid and redeemed by
the Company at the applicable Redemption Price, together with accrued interest
(including any Additional Interest) to the Redemption Date; provided, however,
that, unless otherwise specified as contemplated by Section 3.1, installments of
interest whose Stated Maturity is on or prior to the Redemption Date will be
payable to the Holders of such Securities, or one or more Predecessor
Securities, registered as such at the close of business on the relevant Record
Dates according to their terms and the provisions of Section 3.7.

     Upon presentation of any Security redeemed in part only, the Company shall
execute and the Trustee shall authenticate and deliver to the Holder thereof, at
the expense of the Company, a new Security or Securities of the same series, of
authorized denominations, in aggregate principal amount

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<PAGE>

equal to the unredeemed portion of the Security so presented and having the same
Original Issue Date, Stated Maturity and terms. If a Global Security is so
surrendered, such new Security will also be a new Global Security.

     If any Security called for redemption shall not be so paid upon surrender
thereof for redemption, the principal of and premium, if any, on such Security
shall, until paid, bear interest from the Redemption Date at the rate prescribed
therefor in the Security.

     Section 11.7  Right of Redemption of Securities Initially Issued to a ONEOK
Capital Trust.

     In the case of the Securities of a series initially issued to a ONEOK
Capital Trust, except as otherwise specified as contemplated by Section 3.1, the
Company, at its option, may redeem such Securities (i) on or after the date five
years after the Original Issue Date of such Securities, in whole at any time or
in part from time to time, or (ii) upon the occurrence and during the
continuation of a Special Event, at any time within 90 days following the
occurrence of such Special Event in respect of such ONEOK Capital Trust, in
whole (but not in part), in each case at a Redemption Price equal to 100% of the
principal amount thereof.


                                   ARTICLE XII

                                 SINKING FUNDS

     Section 12.1  Applicability of Article.

     The provisions of this Article shall be applicable to any sinking fund for
the retirement of Securities of any series except as otherwise specified as
contemplated by Section 3.1 for such Securities.

     The minimum amount of any sinking fund payment provided for by the terms of
any Securities of any series is herein referred to as a "mandatory sinking fund
payment", and any sinking fund payment in excess of such minimum amount which is
permitted to be made by the terms of such Securities of any series is herein
referred to as an "optional sinking fund payment".  If provided for by the terms
of any Securities of any series, the cash amount of any sinking fund payment may
be subject to reduction as provided in Section 12.2.  Each sinking fund payment
shall be applied to the redemption of Securities of any series as provided for
by the terms of such Securities.

     Section 12.2  Satisfaction of Sinking Fund Payments with Securities.

     In lieu of making all or any part of a mandatory sinking fund payment with
respect to any Securities of a series in cash, the Company may at its option, at
any time no more than 16 months and no less than 30 days prior to the date on
which such sinking fund payment is due, deliver to the Trustee Securities of
such series (together with the unmatured coupons, if any, appertaining thereto)
theretofore purchased or otherwise acquired by the Company, or credit securities
previously canceled or otherwise delivered to the Trustee for cancellation,
except Securities of such series that have been redeemed through the application
of mandatory or optional sinking fund payments pursuant to the terms of the
Securities of such series, accompanied by a Company Order instructing the
Trustee to

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<PAGE>

cancel such Securities if not previously canceled or credit such obligations and
stating that the Securities of such series were originally issued by the Company
by way of bona fide sale or other negotiation for value; provided that the
Securities to be so credited have not been previously so credited. The
Securities to be so credited shall be received and credited for such purpose by
the Trustee at the Redemption Price for such Securities, as specified in the
Securities so to be redeemed, for redemption through operation of the sinking
fund and the amount of such sinking fund payment shall be reduced accordingly.

     Section 12.3  Redemption of Securities for Sinking Fund.

     Not less than 60 days prior to each sinking fund payment date for any
series of Securities, the Company will deliver to the Trustee an Officers'
Certificate specifying the amount of the next ensuing sinking fund payment for
such Securities pursuant to the terms of such Securities, the portion thereof;
if any, which is to be satisfied by payment of cash in the currency in which the
Securities of such series are payable (except as provided pursuant to Section
3.1) and the portion thereof; if any, which is to be satisfied by delivering and
crediting Securities pursuant to Section 12.2 and will also deliver to the
Trustee any Securities to be so delivered.  Such Officers' Certificate shall be
irrevocable and upon its delivery the Company shall be obligated to make the
cash payment or payments therein referred to, if any, on or before the
succeeding sinking fund payment date.  In the case of the failure of the Company
to deliver such Officers' Certificate (or, as required by this Indenture, the
Securities and coupons, if any, specified in such Officers' Certificate), the
sinking fund payment due on the succeeding sinking fund payment date for such
series shall be paid entirely in cash and shall be sufficient to redeem the
principal amount of the Securities of such series subject to a mandatory sinking
fund payment without the right to deliver or credit securities as provided in
Section 12.2 and without the right to make the optional sinking fund payment
with respect to such series at such time.

     Any sinking fund payment or payments (mandatory or optional) made in cash
plus any unused balance of any preceding sinking fund payments made with respect
to the Securities of any particular series shall be applied by the Trustee (or
by the Company if the Company is acting as its own Paying Agent) on the sinking
fund payment date on which such payment is made (or, if such payment is made
before a sinking fund payment date, on the sinking fund payment date immediately
following the date of such payment) to the redemption of Securities of such
series at the Redemption Price specified in such Securities with respect to the
sinking fund.  Any sinking fund moneys not so applied or allocated by the
Trustee (or, if the Company is acting as its own Paying Agent, segregated and
held in trust by the Company as provided in Section 10.3) for such series and
together with such payment (or such amount so segregated) shall be applied in
accordance with the provisions of this Section 12.3.  Any and all sinking fund
moneys with respect to the Securities of any particular series held by the
Trustee (or if the Company is acting as its own Paying Agent, segregated and
held in trust as provided in Section 10.3) on the last sinking fund payment date
with respect to Securities of such series and not held for the payment or
redemption of particular Securities of such series shall be applied by the
Trustee (or by the Company if the Company is acting as its own Paying Agent),
together with other moneys, if necessary, to be deposited (or segregated)
sufficient for the purpose, to the payment of the principal of the Securities of
such series at Maturity.  The Trustee shall select the Securities to be redeemed
upon such sinking fund payment date in the manner specified in Section 11.3 and
cause notice of the redemption thereof to be given in the name of and at the
expense of the Company in the manner provided in Section 11.4.  Such notice
having been duly given, the redemption of such Securities shall be made upon the
terms and in the manner stated in Section 11.6.  On or before each

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sinking fund payment date, the Company shall pay to the Trustee (or, if the
Company is acting as its own Paying Agent, the Company shall segregate and hold
in trust as provided in Section 10.3) in cash a sum in the currency in which
Securities of such series are payable (except as provided pursuant to Section
3.1) equal to the principal and any interest accrued to the Redemption Date for
Securities or portions thereof to be redeemed on such sinking fund payment date
pursuant to this Section 12.3.

     Neither the Trustee nor the Company shall redeem any Securities of a series
with sinking fund moneys or mail any notice of redemption of Securities of such
series by operation of the sinking fund for such series during the continuance
of a default in payment of interest, if any, on any Securities of such series or
of any Event of Default (other than an Event of Default occurring as a
consequence of this paragraph) with respect to the Securities of such series,
except that if the notice of redemption shall have been provided in accordance
with the provisions hereof; the Trustee (or the Company, if the Company is then
acting as its own Paying Agent) shall redeem such Securities if cash sufficient
for that purpose shall be deposited with the Trustee (or segregated by the
Company) for that purpose in accordance with the terms of this Article XII.
Except as aforesaid, any moneys in the sinking fund for such series at the time
when any such default or Event of Default shall occur and any moneys thereafter
paid into such sinking fund shall, during the continuance of such default or
Event of Default, be held as security for the payment of the Securities and
coupons, if any, of such series; provided, however, that in case such default or
Event of Default shall have been cured or waived herein, such moneys shall
thereafter be applied on the next sinking fund payment date for the Securities
of such series on which such moneys may be applied pursuant to the provisions of
this Section 12.3.


                                   ARTICLE XII

                          SUBORDINATION OF SECURITIES

     Section 13.1  Securities Subordinate to Senior Debt.

     The Company covenants and agrees, and each Holder of a Security, by its
acceptance thereof, likewise covenants and agrees, that, to the extent and in
the manner hereinafter set forth in this Article, the payment of the principal
of (and premium, if any) and interest (including any Additional Interest) on
each and all of the Securities are hereby expressly made subordinate and subject
in right of payment to the prior payment in full of all Senior Debt of the
Company.

     Section 13.2  Payment Over of Proceeds Upon Dissolution, Etc.

     In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company (each such event, if any, herein
sometimes referred to as a "Proceeding"), then the holders of Senior Debt of the
Company shall be entitled to receive payment in full of all Allocable Amounts of
such Senior Debt, or provision shall be made for such payment in cash or cash
equivalents or otherwise in a manner satisfactory to the holders of Senior Debt
of the Company before the Holders of the Securities are entitled to receive or
retain any payment or distribution of any kind or character, whether in cash,
property or securities (including any payment or distribution which may be
payable or deliverable by reason of the payment of any other Debt of the Company
(including any series of

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<PAGE>

the Securities) subordinated to the payment of the Securities, such payment or
distribution being hereinafter referred to as a "Junior Subordinated Payment"),
on account of principal of (or premium, if any) or interest (including any
Additional Interest) on the Securities or on account of the purchase or other
acquisition of Securities by the Company and to that end the holders of Senior
Debt of the Company shall be entitled to receive, for application to the payment
thereof; any payment or distribution of any kind or character, whether in cash,
property or securities, including any Junior Subordinated Payment, which may be
payable or deliverable in respect of the Securities in any such Proceeding.

     In the event that, notwithstanding the foregoing provisions of this
Section, the Trustee or the Holder of any Security shall have received any
payment or distribution of assets of the Company of any kind or character,
whether in cash, property or securities, including any Junior Subordinated
Payment, before all Allocable Amounts of all Senior Debt of the Company are paid
in full or payment thereof is provided for in cash or cash equivalents or
otherwise in a manner satisfactory to the holders of Senior Debt of the Company,
and if such fact shall, at or prior to the time of such payment or distribution,
have been made known to the Trustee or, as the case may be, such Holder, then
and in such event such payment or distribution shall be paid over or delivered
forthwith to the trustee in bankruptcy, receiver, liquidating trustee,
custodian, assignee, agent or other Person making payment or distribution of
assets of the Company for application to the payment of all Allocable Amounts of
all Senior Debt of the Company remaining unpaid, to the extent necessary to pay
all Allocable Amounts of all Senior Debt of the Company in full, after giving
effect to any concurrent payment or distribution to or for the holders of Senior
Debt of the Company.

     For purposes of this Article only, the words "any payment or distribution
of any kind or character, whether in cash, property or securities" shall not be
deemed to include shares of stock of the Company as reorganized or readjusted,
or securities of the Company or any other corporation provided for by a plan of
reorganization or readjustment which securities are subordinated in right of
payment to all then outstanding Senior Debt of the Company to substantially the
same extent as the Securities are so subordinated as provided in this Article.
The consolidation of the Company with, or the merger of the Company into,
another Person or the liquidation or dissolution of the Company following the
sale of all or substantially all of its properties and assets as an entirety to
another Person upon the terms and conditions set forth in Article VIII shall not
be deemed a Proceeding for the purposes of this Section if the Person formed by
such consolidation or into which the Company is merged or the Person which
acquires by sale such properties and assets as an entirety, as the case may be,
shall, as a part of such consolidation, merger, or sale comply with the
conditions set forth in Article VIII.

     Section 13.3  Prior Payment to Senior Debt Upon Acceleration of Securities.

     In the event that any Securities are declared due and payable before their
Stated Maturity, then and in such event the holders of the Senior Debt of the
Company outstanding at the time such Securities so become due and payable shall
be entitled to receive payment in full of all Allocable Amounts due on or in
respect of such Senior Debt (including any amounts due upon acceleration), or
provision shall be made for such payment in cash or cash equivalents or
otherwise in a manner satisfactory to the holders of Senior Debt of the Company
before the Holders of the Securities are entitled to receive any payment or
distribution of any kind or character, whether in cash, properties or securities
(including any Junior Subordinated Payment) by the Company on account of the

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<PAGE>

principal of (or premium, if any) or interest (including any Additional
Interest) on the Securities or on account of the purchase or other acquisition
of Securities by the Company ; provided, however, that nothing in this Section
shall prevent the satisfaction of any sinking fund payment in accordance with
this Indenture or as otherwise specified as contemplated by Section 3.1 for the
Securities of any series by delivering and crediting pursuant to Section 12.2 or
as otherwise specified as contemplated by Section 3.1 for the Securities of any
series Securities which have been acquired (upon redemption or otherwise) prior
to such declaration of acceleration.

     In the event that, notwithstanding the foregoing, the Company shall make
any payment to the Trustee or the Holder of any Security prohibited by the
foregoing provisions of this Section, and if such fact shall, at or prior to the
time of such payment, have been made known to the Trustee or, as the case may
be, such Holder, then and in such event such payment shall be paid over and
delivered forthwith to the Company.

     The provisions of this Section shall not apply to any payment with respect
to which Section 13.2 would be applicable.

     Section 13.4  No Payment When Senior Debt in Default.

     (a)  In the event and during the continuation of any default in the payment
of principal of (or premium, if any) or interest on any Senior Debt of the
Company, or in the event that any event of default with respect to any Senior
Debt of the Company shall have occurred and be continuing and shall have
resulted in such Senior Debt becoming or being declared due and payable prior to
the date on which it would otherwise have become due and payable, unless and
until such event of default shall have been cured or waived or shall have ceased
to exist and such acceleration shall have been rescinded or annulled, or (b) in
the event any judicial proceeding shall be pending with respect to any such
default in payment or such event or default, then no payment or distribution of
any kind or character, whether in cash, properties or securities (including any
Junior Subordinated Payment) shall be made by the Company on account of
principal of (or premium, if any) or interest (including any Additional
Interest), if any, on the Securities or on account of the purchase or other
acquisition of Securities by the Company, in each case unless and until all
Allocable Amounts of such Senior Debt are paid in full; provided, however, that
nothing in this Section shall prevent the satisfaction of any sinking fund
payment in accordance with this Indenture or as otherwise specified as
contemplated by Section 3.1 for the Securities of any series by delivering and
crediting pursuant to Section 12.2 or as otherwise specified as contemplated by
Section 3.1 for the Securities of any series Securities which have been acquired
(upon redemption or otherwise) prior to such default in payment or event of
default.

     In the event that, notwithstanding the foregoing, the Company shall make
any payment to the Trustee or the Holder of any Security prohibited by the
foregoing provisions of this Section, and if such fact shall, at or prior to the
time of such payment, have been made known to the Trustee or, as the case may
be, such Holder, then and in such event such payment shall be paid over and
delivered forthwith to the Company.

     The provisions of this Section shall not apply to any payment with respect
to which Section 13.2 would be applicable.

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     Section 13.5  Payment Permitted If No Default.

     Nothing contained in this Article or elsewhere in this Indenture or in any
of the Securities shall prevent (a) the Company at any time except during the
pendency of any Proceeding with respect to it referred to in Section 13.2 or
under the conditions described in Sections 13.3 and 13.4, from making payments
at any time of principal of (and premium, if any) or interest (including
Additional Interest) on the Securities or (b) the application by the Trustee of
any money deposited with it hereunder to the payment of or on account of the
principal of (and premium, if any) or interest (including any Additional
Interest) on the Securities or the retention of such payment by the Holders, if,
at the time of such application by the Trustee, it did not have knowledge that
such payment would have been prohibited by the provisions of this Article.

     Section 13.6  Subrogation to Rights of Holders of Senior Debt.

     Subject to the payment in full of all amounts due or to become due on all
Senior Debt of the Company or the provision for such payment in cash or cash
equivalents or otherwise in a manner satisfactory to the holders of Senior Debt
of the Company the Holders of the Securities shall be subrogated to the extent
of the payments or distributions made to the holders of such Senior Debt
pursuant to the provisions of this Article (equally and ratably with the holders
of all indebtedness of the Company which by its express terms is subordinated to
Senior Debt of the Company to substantially the same extent as the Securities
are subordinated to the Senior Debt of the Company and is entitled to like
rights of subrogation by reason of any payments or distributions made to holders
of such Senior Debt) to the rights of the holders of such Senior Debt to receive
payments and distributions of cash, property and securities applicable to the
Senior Debt of the Company until the principal of (and premium, if any) and
interest on the Securities shall be paid in full.  For purposes of such
subrogation, no payments or distributions to the holders of the Senior Debt of
the Company of any cash, property or securities to which the Holders of the
Securities or the Trustee would be entitled except for the provisions of this
Article, and no payments over pursuant to the provisions of this Article to the
holders of Senior Debt of the Company by Holders of the Securities or the
Trustee, shall, as among the Company its creditors other than holders of its
Senior Debt, and the Holders of the Securities, be deemed to be a payment or
distribution by the Company to or on account of its Senior Debt.

     Section 13.7  Provisions Solely to Define Relative Rights.

     The provisions of this Article are and are intended solely for the purpose
of defining the relative rights of the Holders of the Securities on the one hand
and the holders of Senior Debt of the Company on the other hand.  Nothing
contained in this Article or elsewhere in this Indenture or in the Securities is
intended to or shall (a) impair, as between the Company and the Holders of the
Securities, the obligations of the Company, which are absolute and
unconditional, to pay to the Holders of the Securities the principal of (and
premium, if any) and interest (including any Additional Interest) on the
Securities as and when the same shall become due and payable in accordance with
their terms; or (b) affect the relative rights against the Company of the
Holders of the Securities and creditors of the Company other than their rights
in relation to the holders of Senior Debt of the Company; or (c) prevent the
Trustee or the Holder of any Security from exercising all remedies otherwise
permitted by applicable law upon default under this Indenture including, without
limitation, filing and voting claims in any Proceeding with respect to the
Company subject to the rights, if any,

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under this Article of the holders of Senior Debt with respect to the Company to
receive cash, property and securities otherwise payable or deliverable to the
Trustee or such Holder.

     Section 13.8  Trustee to Effectuate Subordination.

     Each Holder of a Security by his or her acceptance thereof authorizes and
directs the Trustee on his or her behalf to take such action as may be necessary
or appropriate to acknowledge or effectuate the subordination provided in this
Article and appoints the Trustee his or her attorney-in-fact for any and all
such purposes.

     Section 13.9  No Waiver of Subordination Provisions.

     No right of any present or future holder of any Senior Debt with respect to
the Company to enforce subordination as herein provided shall at any time in any
way be prejudiced or impaired by any act or failure to act on the part of the
Company or by any act or failure to act, in good faith, by any such holder, or
by any noncompliance by the Company with the terms, provisions and covenants of
this Indenture, regardless of any knowledge thereof that any such holder may
have or be otherwise charged with.

     Without in any way limiting the generality of the immediately preceding
paragraph, the holders of Senior Debt with respect to the Company may, at any
time and from to time, without the consent of or notice to the Trustee or the
Holders of the Securities, without incurring responsibility to the Holders of
the Securities and without impairing or releasing the subordination provided in
this Article or the obligations hereunder of the Holders of the Securities to
the holders of such Senior Debt, do any one or more of the following: (i) change
the manner, place or terms of payment or extend the time of payment of, or renew
or alter, Senior Debt with respect to the Company or otherwise amend or
supplement in any manner Senior Debt with respect to the Company or any
instrument evidencing the same or any agreement under which Senior Debt with
respect to the Company is outstanding; (ii) sell, exchange, release or otherwise
deal with any property pledged, mortgaged or otherwise securing Senior Debt with
respect to the Company; (iii) release any Person liable in any manner for the
collection of Senior Debt with respect to the Company; and (iv) exercise or
refrain from exercising any rights against the Company and any other Person.

     Section 13.10 Notice to Trustee.

     The Company shall give prompt written notice to the Trustee of any fact
known to it which would prohibit the making of any payment to or by the Trustee
in respect of the Securities. Notwithstanding the provisions of this Article or
any other provision of this Indenture, the Trustee shall not be charged with
knowledge of the existence of any facts which would prohibit the making of any
payment to or by the Trustee in respect of the Securities, unless and until the
Trustee shall have received written notice thereof from the Company or a holder
of Senior Debt thereof or from any trustee, agent or representative therefor;
provided, however, that if the Trustee shall not have received the notice
provided for in this Section at least two Business Days prior to the date upon
which by the terms hereof any monies may become payable for any purpose
(including, without limitation, the payment of the principal of (and premium, if
any) or interest (including any Additional Interest) on any Security), then,
anything herein contained to the contrary notwithstanding, the Trustee shall
have full power and authority to receive such monies and to apply the same to
the

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purpose for which they were received and shall not be affected by any notice
to the contrary which may be received by it within two Business Days prior to
such date.

     Subject to the provisions of Section 6.1, the Trustee shall be entitled to
rely on the delivery to it of a written notice by a Person representing himself
to be a holder of Senior Debt of the Company, (or a trustee therefor) to
establish that such notice has been given by a holder of Senior Debt of the
Company, (or a trustee therefor).  In the event that the Trustee determines in
good faith that further evidence is required with respect to the right of any
Person as a holder of Senior Debt of the Company to participate in any payment
or distribution pursuant to this Article, the Trustee may request such Person to
furnish evidence to the reasonable satisfaction of the Trustee as to the amount
of Senior Debt of the Company held by such Person, the extent to which such
Person is entitled to participate in such payment or distribution and any other
facts pertinent to the rights of such Person under this Article, and if such
evidence is not furnished, the Trustee may defer any payment to such Person
pending judicial determination as to the right of such Person to receive such
payment.

     Section 13.11  Reliance on Judicial Order or Certificate of Liquidating
Agent.

     Upon any payment or distribution of assets of the Company referred to in
this Article, the Trustee, subject to the provisions of Section 6.1, and the
Holders of the Securities shall be entitled to rely upon any order or decree
entered by any court of competent jurisdiction in which such Proceeding is
pending, or a certificate of the trustee in bankruptcy, receiver, liquidating
trustee, custodian, assignee for the benefit of creditors, agent or other Person
making such payment or distribution, delivered to the Trustee or to the Holders
of Securities, for the purpose of ascertaining the Persons entitled to
participate in such payment or distribution, the holders of the Senior Debt and
other indebtedness of the Company the amount thereof or payable thereon, the
amount or amounts paid or distributed thereon and all other facts pertinent
thereto or to this Article.

     Section 13.12  Trustee Not Fiduciary for Holders of Senior Debt.

     The Trustee, in its capacity as trustee under this Indenture, shall not be
deemed to owe any fiduciary duty to the holders of Senior Debt of the Company
and shall not be liable to any such holders if it shall in good faith mistakenly
pay over or distribute to Holders of Securities or to the Company, or to any
other Person cash, property or securities to which any holders of Senior Debt of
the Company shall be entitled by virtue of this Article or otherwise.

     Section 13.13  Rights of Trustee as Holder of Senior Debt; Preservation of
Trustee 's Rights.

     The Trustee in its individual capacity shall be entitled to all the rights
set forth in this Article with respect to any Senior Debt of the Company which
may at any time be held by it, to the same extent as any other holder of such
Senior Debt, and nothing in this Indenture shall deprive the Trustee of any of
its rights as such holder.  Nothing in this Article shall be construed to apply
to claims of the Trustee or any predecessor Trustee under Section 5.6 or 6.7.

     Section 13.14  Article Applicable to Paying Agents.

     In case at any time any Paying Agent other than the Trustee shall have been
appointed by the Company and be then acting hereunder, the term "Trustee" as
used in this Article shall in such case

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(unless the context otherwise requires) be construed as extending to and
including such Paying Agent within its meaning as fully for all intents and
purposes as if such Paying Agent were named in this Article in addition to or in
place of the Trustee.

     Section 13.15  Certain Conversions or Exchanges Deemed Payment.

     For the purposes of this Article only, (a) the issuance and delivery of
junior securities upon conversion or exchange of Securities shall not be deemed
to constitute a payment or distribution on account of the principal of (or
premium, if any) or interest (including any Additional Interest) on Securities
or on account of the purchase or other acquisition of Securities, and (b) the
payment, issuance or delivery of cash, property or securities (other than junior
securities) upon conversion or exchange of a Security shall be deemed to
constitute payment on account of the principal of such security.  For the
purposes of this Section, the term "junior securities" means (i) shares of any
stock of any class of the Company and (ii) securities of the Company which are
subordinated in right of payment to all Senior Debt thereof which may be
outstanding at the time of issuance or delivery of such securities to
substantially the same extent as, or to a greater extent than, the Securities
are so subordinated as provided in this Article.

                                    * * * *

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     This instrument may be executed in any number of counterparts, each of
which so executed shall be deemed to be an original, but all such counterparts
shall together constitute but one and the same instrument.

     IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be
duly executed, and their respective corporate seals to be hereunto affixed and
attested, all as of the day and year first above written.

ONEOK, INC.



_______________________________
By:

Attest:



_______________________________

_______________________________

[__________]
as Trustee


_______________________________
By:

Attest:



_______________________________

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