
<PAGE>   1



                                  EXHIBIT 10.7


         THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
         1933.  THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, OR
         HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT
         RELATED THERETO OR AN OPINION OF COUNSEL (WHICH MAY BE COMPANY
         COUNSEL) REASONABLY SATISFACTORY To THE COMPANY THAT SUCH REGISTRATION
         IS NOT REQUIRED UNDER THE SECURITIES ACT OF 1933.

                               WARRANT AGREEMENT

             To Purchase Shares of the Series A Preferred Stock of
                                Steritech, Inc.
                            dated as of May 11, 1992

       WHEREAS, Steritech, Inc., a California corporation (the "Company") has
entered into a Master Lease Agreement dated as of May 11, 1992, Equipment
Schedule No. VL-1, and related Summary Equipment Schedules (the "Leases") with
Comdisco, Inc., a Delaware corporation (the "Warrantholder"); and

       WHEREAS, the Company desires to grant to Warrantholder, in consideration
for such Leases, the right to purchase shares of its Series A Preferred Stock;

       NOW, THEREFORE, in consideration of the Warrantholder executing and
delivering such Leases and in consideration of mutual covenants and agreements
contained herein, the Company and Warrantholder certify and agree as follows:

1.     GRANT OF THE RIGHT TO PURCHASE SERIES A PREFERRED STOCK.

       For value received, the Company hereby grants to the
Warrantholder, and the Warrantholder is entitled, upon the terms and subject to
the conditions hereinafter set forth, to subscribe for and purchase, from the
Company, 20,779 fully paid and non-assessable shares of the Company's Series A
Preferred Stock ("Preferred Stock") at a purchase price of $3.85 per share (the
"Exercise Price").  The number and purchase price of such shares are subject to
adjustment as provided in section 8 hereof.

2.     TERM OF THE WARRANT AGREEMENT.

       Except as otherwise provided for herein, the term of this Warrant
Agreement and the right to purchase Preferred Stock as granted herein shall
commence on the date of execution hereof and shall be exercisable for a period
of (i) ten (10) years after the date of execution hereof, or (ii) five (5)
years from the effective date of the Company's initial public offering,
whichever is shorter.

3.     EXERCISE OF THE PURCHASE RIGHTS.

       The purchase rights set forth in this Warrant Agreement are
exercisable by the Warrantholder, in whole or in part, at any time, or from
time to time, prior to the expiration of the term set forth in Section 2 above,
by tendering to the Company at its principal office a notice of exercise in the
form attached hereto as Exhibit I
<PAGE>   2
(the "Notice of Exercise"), duly completed and executed.  Upon receipt of the
Notice of Exercise and the payment of the purchase price in accordance with the
terms set forth below, the Company shall issue to the Warrantholder a
certificate for the number of shares of Preferred Stock purchased and shall
execute the Notice of Exercise indicating the number of shares which remain
subject to future purchases, if any.

       Notwithstanding anything to the contrary contained in section 2 above or
this Section 3, the Warrantholder shall either (i) exercise this Warrant by
paying to the Company, by cash or check, an amount equal to the aggregate
Warrant Price of the shares being purchased, or (ii) receive shares equal to
the value (as determined below) of this Warrant by surrender of the Warrant at
the principal office of the Company together with notice of such election in
which event the Company shall issue to the Warrantholder a number of shares of
Preferred computed using the following formula:

                 X = Y(A-B)
                     -------
                       A

Where:           X = the number of shares of Preferred to be issued to the
                     Warrantholder.

                 Y = the number of shares of Preferred under this Warrant.

                 A = the fair market value of one share of Preferred Stock.

                 B = Exercise Price.

         As used herein, current fair market value of Preferred Stock
shall mean with respect to each share of Preferred Stock the average of the
closing prices of the Company's Common Stock (times the number of shares of
Common Stock that a share of Preferred Stock is convertible into) sold on all
securities exchanges on which the Common Stock may at the time be listed, or,
if there have been no sales on any such exchange on any day, the average of the
highest bid and lowest asked prices on all such exchanges at the end of such
day, or, if on any day the Common Stock is not so listed, the average of the
representative bid and asked prices quoted in the NASDAQ System as of 4:00
p.m., New York City time, or, if on any day the Common Stock is not quoted in
the NASDAQ System, the average of the highest bid and lowest asked price on
such day in the domestic over-the-counter market as reported by the National
Quotation Bureau, Incorporated, or any similar successor organization, in each
such case averaged over a period of 21 days consisting of the day as of which
the current fair market value of Common Stock is being determined and the 20
consecutive business days prior to such day.  If at any time the Common Stock
is not listed on any securities exchange or quoted in the NASDAQ System or the
over-the-counter market, the current fair market value of Preferred Stock shall
be the highest price per share which the Company could obtain from a willing
buyer (not a current employee or director) for shares of Preferred Stock sold
by the Company, from authorized but unissued shares, as determined in good
faith by the Board of Directors of the Company, unless (i) the Company shall
become subject to a merger, acquisition or other consolidation pursuant to





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<PAGE>   3
which the Company is not the surviving party, in which case the current fair
market value of the Preferred Stock shall be deemed to be the value received by
the holders of the Company's Series A Preferred Stock for each share of Series A
Preferred Stock (or Common Stock if all such shares have been converted into
Common Stock) pursuant to the Company's Acquisition; or (ii) the Warrantholder
shall purchase such shares in conjunction with the initial underwritten public
offering of the Company's Common Stock (times the number of shares of Common
Stock that a share of Preferred Stock is convertible into) pursuant to a
registration statement filed under the Securities Act of 1933, in which case,
the fair market value of the shares of stock subject to this Warrant shall be
the price at which all registered shares are sold to the public in such
offering.

4.       RESERVATION OF SHARES.

         (a)     Authorization and Reservation of Shares.  During the term of
this Warrant Agreement, the Company will at all times have authorized and
reserved a sufficient number of shares of its Preferred Stock to provide for
the exercise of the rights to purchase Preferred Stock as provided for herein.

         (b)     Registration or Listing.  If any shares of Preferred Stock
required to be reserved for purposes of exercise of the Warrant Agreement
hereunder require registration with or approval of any governmental authority
under any Federal or State law (other than any registration under the
Securities Act of 1933, as then in effect, or any similar Federal statute then
enforced, or any state securities law, required by reason of any transfer
involved in such conversion), or listing on any domestic securities exchange,
before such shares may be issued upon conversion, the Company will, at its
expense and as expeditiously as possible, use its best efforts to cause such
shares to be duly registered, listed or approved for listing on such domestic
securities exchange, as the case may be.

5.       NO FRACTIONAL SHARES OR SCRIP.

         No fractional shares or scrip representing fractional shares
shall be issued upon the exercise of the Warrantholder's rights to purchase
Preferred Stock, but in lieu of such fractional shares the Company shall make a
cash payment therefor upon the basis of the Exercise Price then in effect.

6.       NO RIGHTS AS SHAREHOLDERS.

         This Warrant Agreement does not entitle the Warrantholder to any
voting rights or other rights as a shareholder of the Company prior to the
exercise of the Warrantholder's rights to purchase Preferred Stock as provided
for herein.

7.       WARRANTHOLDER REGISTRY.

         The Company shall maintain a registry showing the name and
address of the registered holder of this Warrant Agreement.





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<PAGE>   4
8.     ADJUSTMENT RIGHTS.

       The purchase price per share and the number or character of shares of
Preferred Stock issuable upon exercise of this Warrant (or any shares of stock
or other securities or property at the time received or issuable upon exercise
of this Warrant) are subject to adjustment from time to time, as follows:

         (a)     Merger and Sale of Assets.  If at any time there shall be a
capital reorganization of the shares of the Company's stock (other than a
combination, reclassification, exchange or subdivision of shares otherwise
provided for herein), or a merger or consolidation of the Company with or into
another corporation when the Company is not the surviving corporation, or the
sale of all or substantially all of the Company's properties and assets to any
other person in such a way that holders of Preferred Stock shall be entitled to
receive stock, securities or other assets or property, then, as a part of such
reorganization, merger, consolidation or sale, lawful provision shall be made
so that the Warrantholder shall thereafter be entitled to receive upon exercise
of its rights to purchase Preferred Stock, the number of shares of Preferred
Stock or other securities of the successor corporation resulting from such
merger or consolidation, to which a holder of the Preferred Stock deliverable
upon exercise of the right to purchase Preferred Stock hereunder would have
been entitled in such capital reorganization, merger, consolidation or sale if
the right to purchase such Preferred Stock hereunder had been exercised
immediately prior to such capital reorganization, merger, consolidation or
sale.  In any such case, appropriate adjustment (as' determined in good faith
by the Company's Board of Directors) shall be made in the application of the
provisions of this Warrant Agreement with respect to the rights and interest of
the Warrantholder after the reorganization, merger, consolidation or sale to
the end that the provisions of this Warrant Agreement (including adjustments of
the Exercise Price and number of shares of Preferred Stock purchasable pursuant
to the terms and conditions of this Warrant Agreement) shall be applicable
after that event, as near as reasonably may be, in relation to any shares
deliverable after that event upon the exercise of the Warrantholder's rights to
purchase Preferred Stock pursuant to this Warrant Agreement.

         (b)     Reclassification of Shares.  If the Company at any time shall,
by combination, reclassification, exchange or subdivision of securities or
otherwise, change any of the securities as to which purchase rights under this
Warrant Agreement exist into the same or a different number of securities of
any other class or classes, this Warrant Agreement shall thereafter represent
the right to acquire such number and kind of securities as would have been
issuable as the result of such change with respect to the securities which were
subject to the purchase rights under this Warrant Agreement immediately prior
to such combination, reclassification, exchange, subdivision or other change.

         (c)     Subdivision or Combination of Shares.  If the Company at any
time shall combine or subdivide its Preferred Stock, the Exercise Price and the
number of shares of Preferred Stock (or any other shares





                                      -4-
<PAGE>   5
of stock or other securities issuable upon exercise of this Warrant) shall be
proportionately adjusted to reflect any such combination or subdivision.

         (d)     Stock Dividends.  If the Company at any time shall pay a
dividend payable in, or make any other distribution (except any distribution
specifically provided for in the foregoing subsections (a), (b) or (c)) with
respect to the Preferred Stock (or any other shares of stock or other
securities at the time issuable upon exercise of this Warrant) then, and in
each such case, the Warrantholder on exercise of its purchase rights under this
Warrant Agreement at any time after the consummation, effective date or record
date of such event, shall receive, in addition to the shares of Preferred Stock
(or such other stock or securities) issuable on such exercise prior to such
date, and without payment of any additional consideration therefor, the
securities or such other property of the Company to which such Warrantholder
would have been entitled upon such date if such Warrantholder had exercised its
purchase rights under this Warrant Agreement as of the date on which holders of
Preferred Stock received or became entitled to receive such shares or all other
additional stock and other securities and property (all subject to further
adjustment as provided in this Warrant Agreement).

         (e)     Adjustments Set Forth in Articles of Incorporation.  In
addition to the foregoing adjustments, the conversion rate of the Preferred
Stock into Common Stock is subject to adjustments as set forth in the Company's
Articles of Incorporation.  The Company represents that as of the date of
execution hereof, each share of Preferred Stock was convertible into one share
of Common Stock.

         (f)     Conversion of Preferred Stock.  In case all the authorized
Preferred Stock of the Company is converted, pursuant to the Company's Articles
of Incorporation, into Common Stock or other securities or property, or the
Preferred Stock otherwise ceases to exist, then, in such case, the purchase
rights under this Warrant Agreement as of the date on which the Preferred Stock
is so converted or ceases to exist (the "Termination Date"), shall immediately
become exercisable for, in lieu of the number of shares of Preferred Stock that
would have been issuable upon such exercise immediately prior to the
Termination Date (the "Formerly Issuable Number of Shares of Preferred Stock"),
the stock and other securities and property which the Warrantholder would have
been entitled to receive upon the Termination date if the Warrantholder had
exercised the purchase rights under this Warrant Agreement with respect to the
Formerly Issuable Number of Shares of Preferred Stock immediately prior to the
Termination Date (all subject to further adjustment as provided in this Warrant
Agreement).

         (g)     Common Stock Dividends.  If the Company at any time following
the conversion of the Preferred Stock and prior to the exercise of the purchase
rights under this Warrant Agreement shall pay a dividend with respect to Common
Stock payable in shares of Common Stock, or make any other distribution with
respect to Common Stock, then the Exercise Price shall be adjusted, from and
after the date of determination of the shareholders entitled to receive such
dividend or distribution, to that price determined by multiplying the Exercise





                                      -5-
<PAGE>   6
Price in effect by a fraction (i) the numerator of which shall be the total
number of shares of Common Stock outstanding immediately prior to such dividend
or distribution, and (ii) the denominator of which shall be the total number of
shares of the Common Stock outstanding immediately after such dividend or
distribution.

         (h)     Notice of Adjustments.  In the event that: (i) the Company
shall declare any dividend or distribution upon its stock, whether in cash,
property, stock or other securities; (ii) the Company shall offer for
subscription prorata to the holders of any class of its Preferred or other
convertible stock any additional shares of stock of any class or other rights;
(iii) there shall be any capital reorganization, reclassification,
consolidation, merger or sale of all or substantially all of the Company's
assets; or (iv) there shall be any voluntary or involuntary dissolution,
liquidation or winding up of the Company; then, in connection with each such
event, the Company shall send to the Warrantholder:

                 (i)     At least ten (10) days' prior written notice of the 
          date on which the books of the Company shall close or a record shall 
          be taken for such dividend, distribution, subscription rights 
          (specifying the date on which the holders of Preferred Stock shall 
          be entitled thereto) or for determining rights to vote in respect of 
          such capital reorganization, reclassification, consolidation, merger 
          or sale of all or substantially all of the Company's assets, 
          dissolution, liquidation or winding up; and

                (ii)     In the case of any such capital reorganization,
          reclassification, consolidation, merger or sale of all or 
          substantially all of the Company's assets, dissolution, liquidation 
          or winding up, at least ten (10) days' prior written notice of the 
          date when the same shall take place (and specifying the date on 
          which the holders of Preferred Stock shall be entitled to exchange 
          their Preferred Stock for securities or other property deliverable
          upon such capital reorganization, reclassification, consolidation, 
          merger or sale of all or substantially all of the Company's assets, 
          dissolution, liquidation or winding up).

          Each such written notice shall set forth, in reasonable detail, (i)
the event requiring the adjustment, (ii) the amount of the adjustment, (iii) the
method by which such adjustment was calculated, (iv) the Exercise Price, and (v)
the number of shares subject to purchase hereunder after giving effect to such
adjustment.

          (i)    Registration and Listing.  The Company will take all such
actions as may be necessary to assure that all shares of Preferred Stock
issuable pursuant to this Warrant Agreement may be so issued without violation
of any applicable law or regulation or any requirements of any domestic stock
exchange (except for official notice of issuance, which will be immediately
transmitted by the Company upon issuance) upon which shares of Preferred Stock
or other shares of the same class may be listed.  The Company will not take any
action which will result in any adjustment of the number of shares of Preferred
Stock issuable upon exercise of this Warrant Agreement if





                                      -6-
<PAGE>   7
the total number of shares of Preferred Stock issuable after such action upon
exercise of the Warrant Agreement then outstanding, together with the total
number of shares of Preferred Stock then outstanding, would exceed the total
number of shares of Preferred Stock then authorized and not reserved for any
purpose other than the purpose of issue upon exercise of the Warrant Agreement.

9.       REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY.  

         Except as set forth in the Schedule of Exceptions attached hereto as
Schedule A, the Company hereby represents and warrants to the Warrantholder as
follows:

         (a)     Reservation of Preferred Stock.  The Preferred Stock issuable
upon exercise of the Warrantholder's rights has been duly and validly reserved
and, when issued in accordance with the provisions of this Warrant Agreement,
will be validly issued, fully paid and nonassessable, and will be free of any
taxes, liens, charges or encumbrances of any nature whatsoever; provided,
however, that the Preferred Stock issuable pursuant to this Warrant Agreement
may be subject to restrictions on transfer under state and/or Federal
securities laws.  The Company has made available to the Warrantholder true,
correct and complete copies of its Articles of Incorporation and By-Laws, as
amended, and minutes of all Board of Directors (including all committees of the
Board of Directors, if any) and all Shareholder meetings.  The issuance of
certificates for shares of Preferred Stock upon exercise of the Warrant
Agreement shall be made without charge to the Warrantholder for any issuance
tax in respect thereof, or other cost incurred by the company in connection
with such exercise and the related issuance of shares of Preferred Stock;
provided that the Company shall not be required to pay any tax which may be
payable in respect of any transfer involved and the issuance and delivery of
any certificate in a name other than that of the Warrantholder.  The Company
will not close its books against the transfer of the Warrant Agreement or of
any share of Preferred Stock issued or issuable upon exercise of the Warrant
and any agreement in any manner which interferes with the timely exercise of
the Warrant.

         (b)     Due Authority.  The execution and delivery by the Company of
the Leases, and this Warrant Agreement and the performance of all obligations
of the Company thereunder and hereunder, including the issuance to
Warrantholder of the right to acquire the shares of Preferred Stock set forth
in Section 1 above (which number of shares may be from time to time adjusted
pursuant to the terms of Section 8 above) have been duly authorized by all
necessary corporate action on the part of the Company, and the Leases and this
Warrant Agreement are not inconsistent with the Company's Articles of
Incorporation or ByLaws, do not contravene any law or governmental rule,
regulation or order applicable to it, do not and will not contravene any
provision of, or constitute a default under, any indenture, mortgage, contract
or other instrument to which it is a party or by which it is bound, and the
Leases and this Warrant Agreement constitute legal, valid and binding
agreements of the Company, enforceable in accordance with their respective
terms.





                                      -7-
<PAGE>   8
         (c)     Consents and Approvals.  No consent or approval of, giving of
notice to, registration with, or taking of any other action in respect of any
state, Federal or other governmental authority or agency is required with
respect to the execution, delivery and performance by the Company of its
obligations under this Warrant Agreement, except for the filing of notices
pursuant to Regulation D under the Securities Exchange Act of 1933, as amended,
(the "1933 Act") and Section 25102 (f) of the California Corporate Securities
Law, which filings will be effective by the time required thereby.

         (d)     Litigation.  There are no actions, suits, audits,
investigations or proceedings pending or, to the knowledge of the Company,
threatened against or affecting the Company in any court or before any
governmental commission, board or authority which, if adversely determined,
will have a material adverse effect on the ability of the Company to perform
its obligations under the Leases and this Warrant Agreement.

         (e)     Subsidiaries or Affiliates.  The Company has no subsidiaries
or affiliated companies and does not otherwise own or control, directly or
indirectly, any other corporation, association or business entity.

         (f)     Issued Securities.  All issued and outstanding shares of
Common Stock, Preferred Stock or any other securities of the Company have been
duly authorized and validly issued and are fully paid and nonassessable.  All
outstanding shares of Common Stock, Preferred Stock and any other securities
were issued in full compliance with all Federal and state securities laws.  In
addition:

                 (i)        The authorized capital of the Company consists of
         (A) 4,000,000 shares of Common Stock, of which 1,010,000 shares are
         issued and outstanding, and (B) 1,026,014 shares of preferred stock,
         of which 740,300 shares have been designated Series A Preferred Stock,
         714,286 of which have been issued and are outstanding and 285,714
         shares have been designated Series B Preferred Stock, none of which
         have been issued or are outstanding.  Each share of Series A Preferred
         Stock and Series B Preferred Stock is convertible into one share of
         Common Stock.

                 (ii)       The Company has reserved (A) 400,000 shares of
         Common Stock for issuance under its stock Option Plan, under which
         56,500 options have been granted subject to qualification with the
         California Department of Corporation at an average price of $.385 per
         share.  The Company has issued warrants exercisable for 285,714 shares
         of Series B Preferred Stock with an exercise price of $5.065 per
         share.  There are no other options, warrants, conversion privileges or
         other rights presently outstanding to purchase or otherwise acquire
         any authorized but unissued shares of the Company's capital stock or
         other securities of the Company.





                                      -8-
<PAGE>   9
                 (iii)      In accordance with the Company's Articles of
         Incorporation, no shareholder of the Company has preemptive rights to
         purchase new issuances of the Company's capital stock.

         (g)     Financial Statements.  The Company has delivered to the
Warrantholder its unaudited Consolidated Balance Sheet and Consolidated
Statement of Income for the two (2) month period ending February 29, 1992 (the
"Financial Statements").  The Financial Statements are complete and correct in
all material respects and have been prepared in accordance with generally
accepted accounting principles (except for the absence of footnotes) applied on
a consistent basis throughout the periods indicated.  The condition and
operating results of the Company as of the dates and during the periods
indicated therein are true and correct in all material aspects, subject as to
the Consolidated Balance Sheet and Consolidated Statement of Income for the two
(2) month period then ending February 29, 1992 to normal year-end audit
adjustments.  Since February 29, 1992 there has been no change in the assets,
liabilities, financial condition or operations of the Company from that
reflected in the Financial Statements other than changes in the ordinary course
of business which have not been, individually or in the aggregate, materially
adverse.

       The Company shall deliver to the Warrantholder (i) within one hundred
twenty (120) days after the end of the Company's fiscal year, statements of
income for such fiscal year, a consolidated balance sheet of the Company as of
the end of such year and consolidated statement of the sources and application
of funds for such year, which year-end financial reports shall be in reasonable
detail and certified by independent public accountants of nationally recognized
standing selected by the Company, and (ii) within forty-five (45) days after
the end of each fiscal quarter other than the last fiscal quarter, unaudited
consolidated statements of income and sources and application of funds for such
quarter and a consolidated balance sheet as of the end of such quarter.

         (h)     Contingent and Absolute Liabilities.  The Company has no
material liabilities or obligations, absolute or contingent except the
liabilities and obligations of the Company as set forth in the Financial
Statements and liabilities and obligations which have occurred in the ordinary
course of business, and which have not been materially adverse.

         (i)     Licenses, Patents and Copyrights.  To the best of the
Company's knowledge, the Company owns, possesses, has access to, or can become
licensed on reasonable terms under, all patents, patent applications,
trademarks, trade names, inventions, franchises, licenses, permits, computer
software and copyrights necessary for the operation of its business as now
conducted, with no known infringement of, or conflict with, the rights of
others.

         (j)     Employee Contracts.  To the best of the Company's knowledge,
no employee of the Company is in violation of any material term of any
employment contract, patent disclosure agreement or any other contract or
agreement relating to the relationship of any such employee with





                                      -9-
<PAGE>   10
the Company or any prior employer because of the nature of the business
conducted by the Company.

         (k)     Insurance.  The Company has in full force and effect insurance
policies, with extended coverage, insuring the Company and its property and
business against such losses and risks, and in such amounts, as are customary
for corporations engaged in a similar business and similarly situated and as
otherwise may be required pursuant to the terms of any other contract or
agreement.

         (1)     Other Commitments to Register Securities.  Except as set forth
in this Warrant Agreement and pursuant to that certain Steritech, Inc.
Investors' Right Agreement dated December 27, 1991, the Company is not,
pursuant to the terms of any other agreement currently in existence, under any
obligation to register under the 1933 Act, any of its presently outstanding
securities or any of its securities which may hereafter be issued.

         (m)     Exempt Transaction.  Subject to the accuracy of the
Warrantholder's representations in Section 10 hereof, the issuance of the
Preferred Stock upon exercise of the Warrantholder's right to purchase such
Preferred Stock will constitute transactions exempt from (i) the registration
requirements of Section 5 of the 1933 Act, in reliance upon Section 4(2)
thereof, and (ii) the qualification requirements of the California Corporations
Code, in reliance upon Section 25102(f).

         (n)     Compliance with Rule 144.  At the written request of the
Warrantholder, who proposes to sell Preferred Stock issuable upon the exercise
of the Warrant in compliance with Rule 144 promulgated by the Securities and
Exchange Commission under the 1933 Act, the Company shall furnish to the
Warrantholder, within ten days after receipt of such request, a written
statement confirming the Company's compliance with the filing requirements of
the Securities and Exchange Commission as set forth in such Rule, as such Rule
may be amended from time to time.

         (o)     No Events of Default, Material Contracts.  All material
contracts, agreements and instruments to which the Company is a party
are in full force and effect in all material respects, and are valid, binding
and enforceable by the Company in accordance with their respective terms,
subject to the effect of applicable bankruptcy and other similar laws affecting
the rights of creditors generally, and rules of law concerning equitable
remedies and no event of default, and no event which, with the passing of time
or the giving of notice, or both, would constitute an event of default has
occurred or is continuing under any such contract, agreement or instrument.

         (p)     Brokers' Fees.  The Company has not incurred, and will not
incur, directly or indirectly, any liability for brokerage or finders' fees or
agents' commissions or any similar charges in connection with the Warrant
Agreement or any other transaction contemplated thereby.

         (q)     Untrue, Misleading Statements.  No representation or warranty
of the Company contained in the Leases, and this Warrant





                                      -10-
<PAGE>   11
Agreement or any certificate or exhibit furnished or to be furnished to
Warrantholder pursuant thereto or in connection with the transactions
contemplated thereby (when read together) contains any untrue statement of a
material fact or omits to state a material fact necessary in order to make the
statements contained therein not misleading.

         (r)     Indebtedness to Employees and Shareholders.  The Company is
not indebted to any employee, shareholder, officer or director of the Company,
and no such employee, shareholder, officer or director is indebted to the
Company.

10.      REPRESENTATIONS AND COVENANTS OF THE WARRANTHOLDER.

         This Warrant Agreement has been entered into by the company in
reliance upon the following representations and covenants of the Warrantholder,
which by its execution hereof the Warrantholder hereby confirms:

         (a)     Investment Purpose.  The right to acquire Preferred Stock or
the Preferred Stock issuable upon exercise of the Warrantholder's rights
contained herein will be acquired for investment and not with a view to the
sale or distribution of any part thereof, and the Warrantholder has no present
intention of selling or engaging in any public distribution of the same except
pursuant to a registration or exemption.

         (b)     Private Issue.  The Warrantholder understands (i) that the
Preferred Stock issuable upon exercise of the Warrantholder's rights contained
herein is not registered under the 1933 Act or qualified under applicable state
securities laws on the ground that the issuance contemplated by this Warrant
Agreement will be exempt from the registration and qualifications requirements
thereof, and (ii) that the Company's reliance on such exemption is predicated
on the representations set forth in this Section 10.

         (c)     Disposition of Warrantholder's Rights.  In no event will the
Warrantholder make a disposition of any of its rights to acquire Preferred
Stock or Preferred Stock issuable upon exercise of such rights unless and until
(i) it shall have notified the Company of the proposed disposition, and (ii) if
requested by the Company, it shall have furnished the Company with an opinion
of counsel (which counsel may either be inside or outside counsel to the
Warrantholder) satisfactory to the Company and its counsel to the effect that
(A) appropriate action necessary for compliance with the 1933 Act has been
taken, or (B) an exemption from the registration requirements of the 1933 Act
is available.  Notwithstanding the foregoing, the restrictions imposed upon the
transferability of any of its rights to acquire Preferred Stock or Preferred
Stock issuable on the exercise of such rights do not apply to transfers from
the beneficial owner of any of the aforementioned securities to its nominee or
from such nominee to its beneficial owner, and shall terminate as to any
particular share of Preferred Stock when (1) such security shall have been
effectively registered under the 1933 Act and sold by the holder thereof in
accordance with such registration or (2) such security





                                      -11-
<PAGE>   12
shall have been sold without registration in compliance with Rule 144 under the
1933 Act, or (3) a letter shall have been issued to the Warrantholder at its
request by the staff of the Securities and Exchange Commission or a ruling
shall have been issued to the Warrantholder at its request by such Commission
stating that no action shall be recommended by such staff or taken by such
Commission, as the case may be, if such security is transferred without
registration under the 1933 Act in accordance with the conditions set forth in
such letter or ruling and such letter or ruling specifies that no subsequent
restrictions on transfer are required.  Whenever the restrictions imposed
hereunder shall terminate, as hereinabove provided, the Warrantholder or holder
of a share of Preferred Stock then outstanding as to which such restrictions
have terminated shall be entitled to receive from the Company, without expense
to such holder, one or more new certificates for the Warrant or for such shares
of Preferred Stock not bearing any restrictive legend.

         (d)     Financial Risk.  The Warrantholder has such knowledge and
experience in financial and business matters as to be capable of evaluating the
merits and risks of its investment and has the ability to bear the economic
risks of its investment.

         (e)     Risk of No Registration.  The Warrantholder understands that
if the Company does not register with the Securities and Exchange Commission
pursuant to Section 12 of the 1933 Act, or file reports pursuant to Section 15
(d), of the Securities Exchange Act of 1934 (the "1934 Act"), or if a
registration statement covering the securities under the 1933 Act is not in
effect when it desires to sell (i) the rights to purchase Preferred Stock
pursuant to this Warrant Agreement, or (ii) the Preferred Stock issuable upon
exercise of the right to purchase, it may be required to hold such securities
for an indefinite period.  The Warrantholder also understands that any sale of
its rights of the Warrantholder to purchase Preferred Stock or Preferred Stock
which might be made by it in reliance upon Rule 144 under the 1933 Act may be
made only in accordance with the terms and conditions of that Rule.

11.  REGISTRATION.

     Warrantholder and Company agree that Warrantholder shall be considered a
"Holder" and that all shares of Common Stock issued upon conversion of the
Preferred Stock subject to this Warrant Agreement shall be considered
"Registrable Securities" and be subject to the same terms and conditions with
respect to the registration and sale of such shares as set forth in Sections
2.3 and 2.4 - 2.13 of that certain Steritech, Inc.  Investors' Rights Agreement
dated December 27, 1991, by and among the Company and those certain Purchasers
identified therein, attached hereto as Exhibit II.

12.  TRANSFERS.

     Subject to the terms and conditions contained in section 10
hereof, this Warrant Agreement and all rights hereunder are transferable in
whole or in part by the Warrantholder and any successor transferee, provided,
however, that in no event shall the





                                      -12-
<PAGE>   13
number of transfers of the rights and interests in all of the Warrants exceed
three (3) transfers.  The transfer shall be recorded on the books of the
Company upon receipt by the Company of a notice of transfer in the form
attached hereto as Exhibit III (the "Transfer Notice"), at its principal
offices and the payment to the Company of all transfer taxes and other
governmental charges imposed on such transfer.

13.      MISCELLANEOUS.

         (a)     Effective Date.  The provisions of this Warrant Agreement
shall be construed and shall be given effect in all respects as if it had been
executed and delivered by the Company on the date hereof. This Warrant Agreement
shall be binding upon any successors or assigns of the Company.

         (b)     Attorney's Fees.  In any litigation, arbitration or court
proceeding between the Company and the Warrantholder relating hereto, the
prevailing party shall be entitled to attorneys' fees and expenses and all
costs of proceedings incurred in enforcing this Warrant Agreement.

         (c)     Governing Law.  This Warrant Agreement shall be governed by
and construed for all purposes under and in accordance with the laws of the
State of California.

         (d)     Counterparts.  This Warrant Agreement may be executed in two
or more counterparts, each of which shall be deemed an original, but all of
which together shall constitute one and the same instrument.

         (e)     Titles and Subtitles.  The titles of the paragraphs and
subparagraphs of this Warrant Agreement are for convenience and are not to be
considered in construing this Agreement.

         (f)     Notices.  Any notice required or permitted hereunder shall be
given in writing and shall be deemed effectively given upon personal delivery
or upon deposit in the United States mail, by registered or certified mail, or
as of the following business by day express mail addressed (i) to the
Warrantholder at 6111 North River Road, Rosemont, Illinois 60018, attention:
Jim Labe, Venture Leasing Director, cc: Legal Department, and (ii) to the
Company at 2341 Stanwell Drive, Concord, California 94520, or at such other
address as any such party may subsequently designate by written notice to the
other party.

         (g)     Specific Performance.  The Company recognizes and agrees that
the Warrantholder will not have an adequate remedy if the Company fails to
comply with this Agreement and that damages will not be readily ascertainable,
and the Company expressly agrees that, in the event of such failure, it shall
not oppose an application by the Warrantholder or any other person entitled to
the benefit of this Agreement requiring specific performance of any or all
provisions hereof or enjoining the Company from continuing to commit any such
breach of this Agreement.





                                      -13-
<PAGE>   14
         (h)     Survival.  The representations, warranties, covenants and
conditions of the respective parties contained herein or made pursuant to this
Warrant Agreement shall survive the execution and delivery of this Warrant
Agreement.

         (i)     Severability.  In the event any one or more of the provisions
of this Warrant Agreement shall for any reason be held invalid, illegal or
unenforceable, the remaining provisions of this Warrant Agreement shall be
unimpaired, and the invalid, illegal or unenforceable provision shall be
replaced by a mutually acceptable valid, legal and enforceable provision, which
comes closest to the intention of the parties underlying the invalid, illegal
or unenforceable provision.

         (j)     Amendments.  Any provision of this Warrant Agreement may be
amended by a written instrument signed by the Company and by the Warrantholder.

         (k)     Additional Documents.  The Company, upon execution of this
Warrant Agreement, shall provide the Warrantholder with certified resolutions
and an opinion from the Company's counsel addressed to the Warrantholder with
respect to the representations, warranties and covenants set forth in
subparagraphs (a) through (f) and subparagraphs (1), (m) and (o) of Section 9
above and shall also supply such other documents as the Warrantholder may from
time to time reasonably request.

         IN WITNESS WHEREOF, the parties hereto have caused this
Warrant Agreement to be executed by its officers thereunto duly authorized.

                                    Company:

                                    STERITECH, INC.

Dated May 3 ,1992                   By:     /s/ [SIG]
                                            --------------------------------

                                    Title:  CEO
                                            --------------------------------
   

                                    Warrantholder:
      
                                    COMDISCO, INC.
      
                                    By:      /s/  [SIG]
                                            --------------------------------    
      
                                    Title:  President
                                            --------------------------------




                                      -14-
<PAGE>   15
                                   Exhibit I

                               NOTICE OF EXERCISE


To:      ____________________________ 
         


(1)      The undersigned Warrantholder hereby elects to purchase ______________
         shares of the Preferred Stock of Steritech, Inc. pursuant to the terms
         of the Warrant Agreement dated the 11th day of May, 1992 (the "Warrant
         Agreement") between Steritech, Inc. and the Warrantholder, and tenders
         herewith payment of the purchase price for such shares in full,
         together with all applicable transfer taxes, if any.

(2)      In exercising its rights to purchase the Preferred Stock of Steritech,
         Inc., the undersigned hereby confirms and acknowledges the investment
         representations and warranties made in Section 10 of the Warrant
         Agreement.

(3)      Please issue a certificate or certificates representing said shares of
         Preferred Stock in the name of the undersigned or in such other name
         as is specified below.


                                    _______________________________________
                                                  (Name)

                                    _______________________________________
                                                  (Address)


                                    Warrantholder: COMDISCO, INC.


                                    By:    __________________________________
                                        
                                         
                                    Title: __________________________________
                                          
                                          
                                    Date:  __________________________________ 
                                        




                                      -15-
<PAGE>   16
                          ACKNOWLEDGEMENT OF EXERCISE


     The undersigned Steritech, Inc. hereby acknowledge receipt of the "Notice
of Exercise" from Comdisco, Inc., to purchase ______________ shares of the
Preferred Stock, of Steritech, Inc. pursuant to the terms of the Warrant
Agreement, and further acknowledges that ____________ shares remain subject to
purchase under the terms of the Warrant Agreement.


                                     Company: STERITECH, INC.


                                     By: _____________________________________
                                          
                                          
                                     Title: __________________________________
                                                                             

                                     Date:  __________________________________
                                          



                                      -16-
<PAGE>   17
                                  Exhibit III

                                TRANSFER NOTICE

         (To transfer or assign the foregoing Warrant Agreement execute this
         form and supply required information.  Do not use this form to 
         purchase shares.)


         FOR VALUE RECEIVED, the foregoing Warrant Agreement and all rights
evidenced thereby are hereby transferred and assigned to

_____________________________________________________________________________   
                                (Please Print)

whose address is ____________________________________________________________


_____________________________________________________________________________


                                       Dated ________________________________


                                       Holder's Signature ___________________


                                       Holder's Address _____________________


                                       ______________________________________


Signature Guaranteed: _______________________________________________________


        NOTE:  The signature to this Transfer Notice must correspond with the
               name as it appears on the face of the Warrant Agreement, without
               alteration or enlargement or any change whatever.  Officers of
               corporations and those acting in a fiduciary or other
               representative capacity should file proper evidence of authority
               to assign the foregoing Warrant Agreement.



                                      -17-
