<PAGE>
                            [WASTE MANAGEMENT LOGO]

                              FOR IMMEDIATE RELEASE

                                                        FOR FURTHER INFORMATION:
                                                          WASTE MANAGEMENT, INC.
                                                                       ANALYSTS:
                                                                     CHERIE RICE
                                                                    713.512.6548
                                                                          MEDIA:
                                                                      SARAH VOSS
                                                                    713.394.2154

                                                                       WMI#02-09


    WASTE MANAGEMENT, INC. SELECTS ERNST & YOUNG LLP AS ITS EXTERNAL AUDITOR

HOUSTON - MARCH 22, 2002 -Waste Management, Inc. (NYSE: WMI) today announced
that the company's Audit Committee has selected Ernst & Young LLP as its
auditor, replacing Arthur Andersen.

         John C. Pope, Chairman of the Audit Committee of the Board of Directors
said, "After a thorough selection process that reviewed several firms, including
Arthur Andersen, the Committee concluded that Ernst & Young would bring the best
combination of talent and attention to the auditing effort. In addition, our
Audit Committee has determined that Ernst & Young, as an independent auditor,
will only provide auditing related services to the Company."

         A. Maurice Myers, Chairman, President and Chief Executive Officer of
Waste Management said, "The full Board accepted the Audit Committee's unanimous
recommendation at a meeting on Wednesday, March 21." Myers noted that the
current Andersen team on Waste Management's account had done a very professional
job. "We simply feel that our responsibility to our shareholders dictated a
review of our outside auditor at this time," he said.

         "This is a new Waste Management with a new executive team pursuing a
new strategy," said Myers. "The selection of Ernst & Young is one more step in
firmly establishing a new Waste Management."

         Myers added: "The company was very pleased to see that Nell Minow of
the Corporate Library, a Washington, D.C.-based research firm that rates boards
of directors, recently named the current Waste Management Board of Directors
'Most Improved Board' as well as giving it an 'A' for its performance. This is a
very active and engaged Board and the selection of a new auditor is another
example of the Board's substantial efforts to serve the company's shareholders."
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         Ernst & Young will begin work immediately and the audit team will be
headquartered in Houston.

         Waste Management, Inc. is its industry's leading provider of
comprehensive waste management services. Based in Houston, the Company serves
municipal, commercial, industrial, and residential customers throughout North
America.

Certain statements contained in this press release include statements that are
"forward-looking statements." Outlined below are some of the risks that the
Company faces and that could affect our financial statements for 2002 and beyond
and that could cause actual results to be materially different from those that
may be set forth in forward-looking statements made by the Company. However,
they are not the only risks that the Company faces. There may be additional
risks that we do not presently know or that we currently believe are immaterial
which could also impair our business. We caution you not to place undue reliance
on these forward-looking statements, which speak only as of their dates. We
undertake no obligation to publicly update or revise any forward-looking
statements, whether as a result of new information, future events or otherwise.
In addition, the Company, from time to time, provides estimates of financial and
other data relating to future periods. Such estimates and other information are
the Company's expectations at the point in time of issuance but may change at
some future point in time. By issuing such estimates the Company has no
obligation, and is not undertaking any obligation, to update such estimates or
provide any other information relating to such estimates.

     o   the outcome of litigation or investigations;

     o   possible changes in our estimates of site remediation requirements,
         final closure and post-closure obligations, compliance and other audits
         and regulatory developments;

     o   the possible impact of regulations on our business, including the cost
         to comply with regulatory requirements and the potential liabilities
         associated with disposal operations, as well as our ability to obtain
         and maintain permits needed to operate our facilities;

     o   the effect of limitations or bans on disposal or transportation of
         out-of-state waste or certain categories of waste;

     o   our ability to improve the productivity of acquired operations and use
         our asset base and strategic position to operate more efficiently;

     o   our ability to accurately assess all of the pre-existing liabilities of
         companies we have acquired and to successfully integrate the operations
         of acquired companies with our existing operations;

     o   possible charges against earnings for certain shut down operations and
         uncompleted acquisitions or development or expansion projects;

     o   possible charges to asset impairments or further impairments to
         long-lived assets resulting from changes in circumstances or future
         business events or decisions;

     o   the effects that trends toward requiring recycling, waste reduction at
         the source and prohibiting the disposal of certain types of wastes
         could have on volumes of waste going to landfills and waste-to-energy
         facilities;

     o   the effect the weather has on our quarter to quarter results, as well
         as the effect of extremely harsh weather on our operations;

     o   the effect that price fluctuations on commodity prices may have on our
         operating revenues;

     o   the effect competition in our industry could have on our ability to
         maintain margins, including uncertainty relating to competition with
         governmental sources that enjoy competitive advantages from tax-exempt
         financing and tax revenue subsidies;

     o   possible defaults under our credit agreements if cash flows are less
         than we expect or capital expenditures are more than we expect, and the
         possibility that we can not obtain additional capital on acceptable
         terms if needed;

     o   possible diversions of management's attention and increases in
         operating expenses due to efforts by labor unions to organize our
         employees;

     o   possible increases in operating expenses due to fuel price increases or
         fuel supply shortages;

     o   the effects of general economic conditions;
<PAGE>

     o   the ability of insurers to fully or timely meet their contractual
         commitments and the effect that litigation against insurance companies
         and any settlements of such litigation may have on our ability to meet
         our past and future liabilities;

     o   our ability to successfully deploy our new enterprise-wide software
         systems;

     o   the outcome of the hearing that the court will hold regarding whether
         the class action settlement we announced on November 7, 2001 is fair,
         reasonable and adequate;

     o   whether, if the class action settlement is approved, there is an appeal
         of that approval and the outcome of any such appeal;

     o   the number of class members who will request to be excluded from the
         class and whether that number is large enough to trigger a provision in
         the class action settlement agreement that will allow termination of
         the agreement;

     o   the number of objectors to the class action settlement;

     o   the outcome of the hearing that the court will hold regarding whether
         the derivative lawsuit settlement we announced on November 7, 2001 is
         fair, reasonable and adequate;

     o   whether, if the derivative lawsuit settlement is approved, there is an
         appeal of that approval and the outcome of any such appeal;

     o   the number of objectors to the derivative lawsuit settlement; and

     o   our ability to implement the Company's restructuring undertaken in
         2002, including, without limitation, the effect of the restructuring on
         business operations.

Additional information regarding these and/or other factors that could
materially affect results and the accuracy of the forward-looking statements
contained herein may be found in Part I, Item 1 and Part II, Item 7 of the
Company's Annual Report on Form 10-K for the year ended December 31, 2001.


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