<PAGE>   1
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                        ALLIED WASTE NORTH AMERICA, INC.

                                    As Issuer

                                       and

                       ALLIED WASTE FINANCE (CANADA) LTD.

                                  As Guarantor

                                       and

                        THE NEW SUBSIDIARIES NAMED HEREIN

                            As Subsidiary Guarantors

                                       to

                         FIRST BANK NATIONAL ASSOCIATION

                                   As Trustee

                               -------------------

                          First Supplemental Indenture

                          Dated as of December 30, 1996

                                       to

                                    Indenture

                          Dated as of December 1, 1996

                               -------------------

================================================================================
<PAGE>   2
      FIRST SUPPLEMENTAL INDENTURE dated as of December 30, 1996 (the "First
Supplemental Indenture") among ALLIED WASTE NORTH AMERICA, INC., a corporation
duly organized and existing under the laws of the State of Delaware, having its
principal office at 7201 E. Camelback Road, Suite 375, Scottsdale, Arizona
85251, as Issuer, ALLIED WASTE FINANCE (CANADA) LTD., a corporation duly
organized and existing under the laws of Canada ("Allied Finance"), having its
principal office at 1 First Canadian Place, 44th floor, Toronto, Ontario M5X lBl
Canada, as Guarantor, each of the NEW SUBSIDIARIES named in Schedule I hereto
(the "New Subsidiaries"), as Subsidiary Guarantors, and FIRST BANK NATIONAL
ASSOCIATION, a national banking association duly organized and existing under
the laws of the United States, as Trustee (the "Trustee").


                                    RECITALS

      Each of the Company, the Guarantors named in the Indenture hereinafter
referred to and Allied Finance, as Future Guarantor, has heretofore executed and
delivered to the Trustee a certain Indenture dated as of December 1, 1996
(herein called the "Indenture"). All capitalized terms used in this First
Supplemental Indenture and not otherwise defined herein shall have the meanings
assigned to them in the Indenture.

      Section 1305(a) of the Indenture provides that Allied Finance shall, and
the Company shall cause Allied Finance to, upon the closing of the Acquisition,
unconditionally guarantee (the "Allied Finance Guarantee") the due and punctual
payment of Allied Parent's obligations under the Parent Guarantee, in accordance
with the terms of this First Supplemental Indenture, the Indenture and the
Securities.

      Section 1305(b) provides that the Company shall cause each Person that
becomes a Restricted Subsidiary after the date of the Indenture (other than Med
Track), upon becoming a Restricted Subsidiary, to become a Subsidiary Guarantor
with respect to the Securities in accordance with the terms of the Indenture and
the Securities.

      Section 901(6) of the Indenture provides that, without the consent of any
Holders, the Company, when authorized by a Board Resolution of the Company, the
Guarantors, when authorized by respective Board Resolutions of the Guarantors,
and the Trustee, at any time and from time to time, may enter into one or more
indentures supplemental to the Indenture, in form satisfactory to the Trustee,
to add new Subsidiary Guarantors pursuant to Section 1305 thereof.

      Allied Finance and the New Subsidiaries have delivered to the Trustee
Opinions of Counsel pursuant to Sections 1305(a) and 1305(b) of the Indenture,
as applicable, stating that this First Supplemental Indenture has been duly
authorized and executed by Allied Finance and each New Subsidiary, as the case
may be, and constitutes a legal, valid, binding and enforceable obligation of
Allied Finance and each New Subsidiary, as the case may be (subject to customary
exceptions concerning creditors' rights and equitable principles that are
acceptable to the Trustee).


                                        1
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      Allied Finance and the New Subsidiaries have delivered to the Trustee
Opinions of Counsel pursuant to Section 903 of the Indenture stating that the
execution of this First Supplemental Indenture is authorized or permitted by the
Indenture.

      All things necessary to authorize the Senior Subordinated Guarantees by
Allied Finance and each New Subsidiary in accordance with the terms of the
Indenture, and to make such Senior Subordinated Guarantees and this First
Supplemental Indenture, when executed (in the case of this First Supplemental
Indenture only) by the parties hereto, the valid and binding agreements and
obligations of such parties and, with respect to this First Supplemental
Indenture only, supplement to the Indenture have been done and performed.

      NOW, THEREFORE, for and in consideration of the premises and the covenants
contained in this First Supplemental Indenture, the parties hereto hereby agree,
for the equal and proportionate benefit of all Holders of the Securities, as
follows:

      SECTION 1. Allied Finance hereby expressly agrees to unconditionally
guarantee to each Holder of a Security authenticated and delivered by the
Trustee, and to the Trustee on behalf of such Holder, the due and punctual
payment of Allied Parent's obligations under the Parent Guarantee when and as
the same shall become due and payable, whether at the Stated Maturity or by
acceleration, call for redemption, purchase or otherwise, in accordance with the
terms of such Security and of the Indenture. In case of Allied Parent's failure
punctually to make any such payment, Allied Finance hereby expressly agrees to
cause such payment to be made punctually when and as the same shall become due
and payable, whether at the Stated Maturity or by acceleration, call for
redemption, purchase or otherwise, and as if such payment were made by Allied
Parent. Allied Finance further expressly agrees to become upon its execution
hereof and simultaneously with the closing of the Acquisition a Guarantor and be
subject to each of the provisions in the Indenture and the Securities with
respect to the Allied Finance Guarantee and to the provisions of the Indenture
and the Securities applicable to Guarantors generally (except to the extent any
of the same would constitute (i) Allied Finance a Guarantor of the Company or
(ii) as having any reimbursement obligation as described under the eighth
paragraph of Section 1301 of the Indenture).

      SECTION 2. Each New Subsidiary hereby expressly agrees to become upon its
execution hereof and simultaneously with the closing of the Acquisition a
Subsidiary Guarantor with respect to the Securities for all purposes under, and
in accordance with, the terms of the Indenture and the Securities and to be
subject to each of the provisions of the Indenture and the Securities applicable
to Subsidiary Guarantors specifically and Guarantors generally (except that (i)
the obligations of Bestan Inc. shall not exceed such amount as would render its
obligations null as prohibited financial assistance contrary to Section 123.66A
of the Companies Act (Quebec) and (ii) no New Subsidiary that subsists under the
laws of Canada or of the Province of Ontario shall have any reimbursement
obligation as described under the eighth paragraph of Section 1301 of the
Indenture).

      SECTION 3. All covenants and agreements in this First Supplemental
Indenture and pursuant to the terms of the Securities and the Indenture by
Allied Finance and each New Subsidiary shall bind their respective successors
and assigns, whether so expressed or not.


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      SECTION 4. Any request, demand, authorization, direction, notice, consent,
waiver or Act of Holders or other document provided for or permitted by the
Indenture to be made upon, given or furnished to, or filed with the Company or
any Guarantor which is delivered to the Company or any Guarantor in accordance
with Section 105 of the Indenture shall be deemed thereby to have been delivered
also to Allied Finance and each New Subsidiary.

      SECTION 5. In case any provision in this First Supplemental Indenture
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 6. Nothing in this First Supplemental Indenture, express or
implied, shall give to any Person, other than the parties hereto and their
successors under the Indenture and the Holders of the Securities, any benefit or
any legal or equitable right, remedy or claim under the Indenture.

      SECTION 7. This First Supplemental Indenture supplements the Indenture and
shall be a part and subject to all the terms thereof. Except as supplemented
hereby, the Indenture shall continue in full force and effect.

      SECTION 8. This First Supplemental Indenture may be executed in any number
of counterparts, each of which as so executed shall be deemed to be an original,
but all such counterparts shall together constitute but one and the same
instrument.

      SECTION 9. THIS FIRST SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

      IN WITNESS WHEREOF, the parties hereto have caused this First Supplemental
Indenture to be duly executed and attested, all as of the day and year first
above written.

                                    ALLIED WASTE NORTH AMERICA, INC.


                                    By: /s/ Roger A. Ramsey
                                       ---------------------------------
                                       Name:  Roger A. Ramsey
                                       Title: Chief Executive Officer


                                    By: /s/ Henry L. Hirvela
                                       ---------------------------------
                                       Name:  Henry L. Hirvela
                                       Title: Vice President

Attest:

  /s/ Steven M. Helm            
---------------------------------


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<PAGE>   5
                                    ALLIED WASTE FINANCE (CANADA) LTD.,
                                         as Guarantor


                                    By: /s/ Steven M. Helm
                                       ---------------------------------
                                       Name:  Steven M. Helm
                                       Title: Secretary and Treasurer

Attest:


  /s/ Henry L. Hirvela
---------------------------------


                                    EACH OF THE NEW SUBSIDIARIES LISTED
                                    ON SCHEDULE I HERETO, as
                                       Subsidiary Guarantor


                                    By: /s/ Henry L. Hirvela
                                       ---------------------------------
                                       Name:  Henry L. Hirvela
                                       Title: Vice President

Attest:


  /s/ Steven M. Helm
---------------------------------


                                    FIRST BANK NATIONAL ASSOCIATION, as
                                       Trustee


                                    By: /s/ Richard H. Prokosch
                                       ---------------------------------
                                       Name:  Richard H. Prokosch
                                       Title: Trust Officer

Attest:


  /s/ Christina Hatfield
---------------------------------


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                                   SCHEDULE I

                                NEW SUBSIDIARIES

Laidlaw Waste Systems, Inc. (Delaware)
Environmental Reclamation Company (Illinois)
Tricil (N.Y.), Inc. (New York)
Laidlaw Waste Systems Holdings, Inc. (Delaware)
Laidlaw Gas Recovery Corporation, Inc. (California)
Laidlaw Gas Recovery Corporation II, Inc. (California)
Laidlaw Gas Recovery Systems, Inc. (California)
CATPAC Two, Inc. (Delaware)
Laidlaw Waste Systems (Adrian) Inc. (Michigan)
Laidlaw Waste Systems (Bellefontaine) Inc. (Ohio)
Laidlaw Waste Systems (Bridgeton) Inc. (Missouri)
Laidlaw Waste Systems (Celina) Inc. (Ohio)
Laidlaw Waste Systems (Chiquita) Inc. (California)
Laidlaw Waste Systems (Colorado) Inc. (Colorado)
Laidlaw Waste Systems (Dallas) Inc. (Delaware)
Laidlaw Waste Systems (Fort Worth) Inc. (Delaware)
Laidlaw Waste Systems (Houston) Inc. (Delaware)
Laidlaw Waste Systems (Jefferson City) Inc. (Missouri)
Laidlaw Waste Systems (Kansas City) Inc. (Missouri)
Laidlaw Waste Systems (Madison) Inc. (Illinois)
Laidlaw Waste Systems (Michigan) Inc. (Delaware)
Laidlaw Waste Systems (Oklahoma City) Inc. (Oklahoma)
Laidlaw Waste Systems (Texas) Inc. (Texas)
Laidlaw Waste Systems (Valley View) Inc. (Kentucky)
Williams County Landfill, Inc. (Ohio)
City Garbage, Inc. (Texas)
Laidlaw Medical Services Inc. (Delaware)
Laidlaw Waste Systems (Belleville) Inc. (Missouri)
Dempsey Waste Systems, Inc. (Ohio)
Laidlaw Waste Systems (Canada) Ltd. (Canada)
Laidlaw Energy Technologies Ltd. (Canada)
Bestan Inc. (Quebec)
Laidlaw Waste Systems (Durham) Ltd. (Ontario)
Laidlaw Waste Systems (Warwick) Ltd. (Ontario)
635952 Ontario Inc. (Ontario)
Laidlaw Waste Systems (Ottawa) Ltd. (Ontario)
Laidlaw Waste Systems (Richmond) Ltd. (Canada)
Laidlaw Waste Systems (Storrington) Ltd. (Canada)
2686848 Canada Inc. (Canada)
Endwaste Inc. (Ontario)
Gestion de Rebuts Quebec Ltee (Canada)
Dechex Ltee (Canada)
Centre de Tri Transit (1) Inc. (Canada)
Location Sanico Ltee (Canada)
Laidlaw Medical Services Ltd. (Canada)
3240720 Canada Inc. (Canada)
Laidlaw Waste Systems Ltd. (Canada)

<PAGE>   7

STATE OF NEW YORK       )
                        )  ss.:
COUNTY OF NEW YORK      )

        On the 30th day of December, 1996 before me personally came Roger A.
Ramsey, to me known, who, being by me duly sworn, did depose and say that he is
the Chief Executive Officer of Allied Waste North America Inc., one of the
corporations described in and which executed the foregoing instrument, and that
he signed his name to said instrument by authority of the Board of Directors of
said corporation.

         NANCY RUBICCO
Notary Public, State of New York
          No. 4949288
Qualified in Westchester County                      /s/ Nancy Rubicco
Commission Expires April 3, 1997                -----------------------------




STATE OF NEW YORK       )
                        )  ss.:
COUNTY OF NEW YORK      )

        On the 30th day of December, 1996 before me personally came Steven M.
Helm, to me known, who, being by me duly sworn, did depose and say that he is
the Secretary and Treasurer of Allied Waste Finance (Canada) Ltd., one of the
corporations described in and which executed the foregoing instrument, and that
he signed his name to said instrument by authority of the Board of Directors of
said corporation.

         NANCY RUBICCO
Notary Public, State of New York
          No. 4949288
Qualified in Westchester County                      /s/ Nancy Rubicco
Commission Expires April 3, 1997                -----------------------------





STATE OF NEW YORK       )
                        )  ss.:
COUNTY OF NEW YORK      )

        On the 30th day of December, 1996 before me personally came Henry L.
Hirvela, to me known, who, being by me duly sworn, did depose and say that he is
a Vice President of Allied Waste North America, Inc. and each of the New
Subsidiaries described in and which executed the foregoing instrument, and that
he signed his name to said instrument by authority of the Board of Directors of
such corporation.

         NANCY RUBICCO
Notary Public, State of New York
          No. 4949288
Qualified in Westchester County                      /s/ Nancy Rubicco
Commission Expires April 3, 1997                -----------------------------




STATE OF MINNESOTA      )
                        )  ss.:
COUNTY OF RAMSEY        )

        On the 30th day of December, 1996 before me personally came RICHARD H.
PROKOSCH, to me known, who, being by me duly sworn, did depose and say that he 
is A TRUST OFFICER of First Bank National Association, the Trustee described in
and which executed the foregoing instrument, that he signed his name to said 
instrument by authority of the Board of Directors of said association.

[STATE]       ARLENE W. KOSEK
 SEAL]   Notary Public - MINNESOTA
              HENNEPIN COUNTY                        /s/ Arlene W. Kosek
My Commission Expires Jan. 31, 2000                -----------------------------