Document:

EX-4.S
             INDENTURE OF TRUST DATED AS OF JULY 1, 1997

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                               INDENTURE OF TRUST

                                     Between

                CALIFORNIA POLLUTION CONTROL FINANCING AUTHORITY

                                       And

                   U.S. BANK, A National Banking Association,
                                   as Trustee

                            Dated as of July 1, 1997

                                   Relating to

                                   $19,500,000
                California Pollution Control Financing Authority
                    Pollution Control Refunding Revenue Bonds
                     (Laidlaw Environmental Services, Inc.)
                                  1997 Series A

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                                TABLE OF CONTENTS

Section                                                                    Page
-------                                                                    ----

Parties.....................................................................  1
Preambles...................................................................  1

                                    ARTICLE I

                                   DEFINITIONS

  1.01.  Definitions........................................................  3
  1.02.  Number and Gender.................................................. 12
  1.03.  Articles, Sections, Etc............................................ 12
  1.04.  Content of Certificates and Opinions............................... 12

                                   ARTICLE II

                                    THE BONDS

  2.01.  Authorization and Terms of Bonds................................... 13
         (a)              Authorization..................................... 13
         (b)              General Terms..................................... 13
         (c)              Interest Rate..................................... 14
         (d)              Form of Bonds..................................... 14
         (e)              Book-Entry System................................. 15
  2.02.  Execution of Bonds................................................. 16
  2.03.  Transfer and Exchange of Bonds..................................... 17
  2.04.  Bond Register...................................................... 17
  2.05.  Reserved........................................................... 18
  2.06.  Bonds Mutilated, Lost, Destroyed or Stolen......................... 18
  2.07.  Disposition of Cancelled Bonds..................................... 18
  2.08.  CUSIP Numbers...................................................... 19

                                   ARTICLE III

                                ISSUANCE OF BONDS

  3.01.  Authentication and Delivery of Bonds............................... 19
  3.02.  Application of Proceeds of Bonds................................... 19

                                   ARTICLE IV

                               REDEMPTION OF BONDS

  4.01.  Redemption of Bonds................................................ 19
  4.02.  Selection of Bonds for Redemption.................................. 22
  4.03.  Notice of Redemption............................................... 22
  4.04.  Partial Redemption of Bonds........................................ 23
  4.05.  Effect of Redemption............................................... 23

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Section                                                                    Page
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                                    ARTICLE V

                                    REVENUES

  5.01.  Pledge of Revenues................................................. 24
  5.02.  Bond Fund.......................................................... 24
  5.03.  Trustee Authorized to Take Actions Under the Agreement............. 25
  5.04.  Investment of Moneys............................................... 25
  5.05.  Assignment to Trustee; Enforcement of Obligations.................. 26
  5.06.  Repayment to Borrower.............................................. 27

                                   ARTICLE VI

                           COVENANTS OF THE AUTHORITY

  6.01.  Payment of Principal and Interest.................................. 27
  6.02.  Extension or Funding of Claims for Interest........................ 27
  6.03.  Paying Agents...................................................... 27
  6.04.  Preservation of Revenues........................................... 28
  6.05.  Compliance with Indenture.......................................... 28
  6.06.  Arbitrage Covenants; Rebate Fund................................... 28
  6.07.  Other Liens........................................................ 29
  6.08.  Further Assurances................................................. 29

                                   ARTICLE VII

                                     DEFAULT

  7.01.  Events of Default; Acceleration; Waiver of Default................. 30
  7.02.  Institution of Legal Proceedings by Trustee........................ 31
  7.03.  Application of Moneys Collected by Trustee......................... 32
  7.04.  Effect of Delay or Omission to Pursue Remedy....................... 33
  7.05.  Remedies Cumulative................................................ 33
  7.06.  Covenant to Pay Bonds in Event of Default.......................... 33
  7.07.  Trustee Appointed Agent for Bondholders............................ 34
  7.08.  Power of Trustee to Control Proceedings............................ 34
  7.09.  Limitation on Bondholders' Right to Sue............................ 34
  7.10.  Limitation of Liability to Revenues................................ 35

                                  ARTICLE VIII

                          THE TRUSTEE AND THE REGISTRAR

  8.01.  Duties, Immunities and Liabilities of Trustee and
         Registrar.......................................................... 36
  8.02.  Right of Trustee and Registrar to Rely upon the
         Agreement, Etc..................................................... 37
  8.03.  Trustee and Registrar Not Responsible for Recitals................. 38
  8.04.  Right of Trustee and Registrar to Acquire Bonds.................... 38
  8.05.  Moneys Received by Trustee and Registrar to Be Held in
         Trust.............................................................. 38

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Section                                                                    Page
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  8.06.  Compensation and Indemnification of Trustee and
         Registrar.......................................................... 38
  8.07.  Qualifications of Trustee and Registrar............................ 40
  8.08.  Resignation and Removal of Trustee or Registrar and
         Appointment of Successor Trustee or Registrar...................... 40
  8.09.  Acceptance of Trust by Successor Trustee........................... 41
  8.10.  Merger or Consolidation of Trustee or Registrar.................... 42
  8.11.  Accounting Records and Reports; Financing Statements............... 42
  8.12.  Registrar.......................................................... 43
  8.13.  Tax Certificate.................................................... 43
  8.14.  Notices to the Authority........................................... 43
  8.15.  Appointment of Co-Trustee.......................................... 44

                                   ARTICLE IX

                      MODIFICATION OF INDENTURE, AGREEMENT

  9.01.  Modification without Consent of Bondholders........................ 45
  9.02.  Modification with Consent of Bondholders........................... 46
  9.03.  Effect of Supplemental Indenture or Amendment...................... 48
  9.04.  Required and Permitted Opinions of Counsel......................... 48
  9.05.  Notation of Modification on Bonds; Preparation of New
         Bonds.............................................................. 48

                                    ARTICLE X

                                   DEFEASANCE

  10.01.  Discharge of Indenture............................................ 49
  10.02.  Discharge of Liability on Bonds................................... 50
  10.03.  Payment of Bonds after Discharge of Indenture..................... 50
  10.04.  Deposit of Money or Securities with Trustee....................... 50

                                   ARTICLE XI

                                  MISCELLANEOUS

  11.01.  Successors of Authority........................................... 51
  11.02.  Limitation of Rights to Parties and Bondholders................... 52
  11.03.  Waiver of Notice.................................................. 52
  11.04.  Separability of Invalid Provisions................................ 52
  11.05.  Notices........................................................... 52
  11.06.  Evidence of Rights of Bondholders................................. 53
  11.07.  Waiver of Personal Liability...................................... 54
  11.08.  Publication of Notices............................................ 54
  11.09.  Governing Law; Venue.............................................. 54
  11.10.  Execution in Several Counterparts................................. 55
  11.11.  Reserved.......................................................... 55
  11.12.  Continuing Disclosure............................................. 55
  11.13.  Opinions of Bond Counsel.......................................... 55

EXHIBIT A FORM OF BOND......................................................A-1
EXHIBIT B TRUSTEE CERTIFICATE...............................................B-1

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         THIS INDENTURE OF TRUST, made and entered into as of July 1, 1997, by
and between the CALIFORNIA POLLUTION CONTROL FINANCING AUTHORITY, a public
instrumentality and political subdivision of the State of California (herein
called the "Authority"), and UNITED STATES NATIONAL BANK OF OREGON, doing
business as U.S. BANK, a national banking association organized under the laws
of the United States with corporate trust offices in Salt Lake City, Utah, being
qualified to accept and administer the trusts hereby created (herein called the
"Trustee"),

                              W I T N E S S E T H:

         WHEREAS, the Authority is a public instrumentality and political
subdivision of the State of California organized and existing under the
California Pollution Control Financing Authority Act, being Division 27
(commencing at section 44500) of the California Health and Safety Code, as
supplemented and amended (the "Act"); and

         WHEREAS, the Act authorizes the Authority to issue its revenue bonds
for the purposes of paying all or any part of the costs of a "project" as
defined in the Act and refunding its outstanding bonds; and

         WHEREAS, in 1992, Laidlaw Inc., a Canadian corporation (the
"Guarantor") and owner of 100% of the common stock of Laidlaw Transportation,
Inc., a Delaware corporation (herein called the "Prior Borrower"), duly caused
an application to be filed with the Authority for financial assistance to
acquire and construct certain hazardous waste treatment and stabilization
facilities indirectly owned by Guarantor in Kern County, California and Imperial
County, California; and

         WHEREAS, in 1992, the Authority issued its Pollution Control Revenue
Bonds (Laidlaw Inc.) 1992 Series A (the "Prior Bonds") to provide funds to
finance the acquisition and construction by the Prior Borrower of such hazardous
waste facilities located in Imperial County, California and Kern County,
California (the "1992 Project"), which qualify as a "project" under the Act; and

         WHEREAS, the Guarantor has sold the 1992 Project to Rollins
Environmental Services, Inc., a Delaware Corporation, which after a merger with
a subsidiary of the Guarantor is now called Laidlaw Environmental Services, Inc.
(the "Borrower"); and

         WHEREAS, following the merger, the Borrower will through its
subsidiaries own certain assets of the Prior Borrower, including the 1992
Project (which hereafter is called the "Project"); and

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         WHEREAS, prior to completion of such sale by the Guarantor, the
Guarantor arranged for the redemption of the Prior Bonds on May 1, 1997, through
the use of an interim loan made by The Toronto-Dominion Bank for that purpose
(the "Interim Loan"); and

         WHEREAS, prior to such redemption on May 1, 1997, this Authority
adopted a resolution expressing its intent to issue refunding bonds in the
future to refinance the Prior Bonds by refunding the Interim Loan; and

         WHEREAS, the sale and merger described above having been completed, the
Borrower has requested that the Authority issue refunding bonds to indirectly
refund the Prior Bonds, and the Authority, after due investigation and
deliberation, has adopted a resolution approving said request; and

         WHEREAS, the Authority proposes to issue its California Pollution
Control Financing Authority Pollution Control Refunding Revenue Bonds (Laidlaw
Environmental Services, Inc.) 1997 Series A, in the aggregate principal amount
of $19,500,000 (the "Bonds") and to loan the proceeds thereof to the Borrower
pursuant to a loan agreement, dated as of July 1, 1997 (the "Agreement"), by and
between the Authority and the Borrower, for the purposes of refinancing the loan
with respect to the Prior Bonds;

         WHEREAS, the issuance and sale of the Bonds and the loan of the
proceeds thereof to the Borrower to indirectly refund the Prior Bonds and
thereby refinance the costs of the 1992 Project will serve the purposes of the
Authority and the Act and in all respects conform to the provisions and
requirements of the Act; and

         WHEREAS, in order to provide for the authentication and delivery of the
Bonds, to establish and declare the terms and conditions upon which the Bonds
are to be issued and secured and to secure the payment of the principal thereof
and of the interest thereon, the Authority has authorized the execution and
delivery of this Indenture; and

         WHEREAS, all Bonds issued under this Indenture will be secured by a
pledge and assignment of the Authority's rights under the aforesaid Agreement
and other security instruments; and

         WHEREAS, all acts and proceedings required by law necessary to make the
Bonds when executed by the Authority, authenticated and delivered by the
Registrar and duly issued, the valid, binding and legal limited obligations of
the Authority, and to constitute this Indenture a valid and binding agreement
for the uses and purposes herein set forth, in accordance with its terms, have
been done and taken; and the execution and delivery of this Indenture have been
in all respects duly authorized; and

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         WHEREAS, in order to provide for the authentication and delivery of the
Bonds, to establish and declare the terms and conditions upon which the Bonds
are to be issued and secured and to secure the payment of the principal thereof
and of the interest thereon, the Authority has authorized the execution and
delivery of this Indenture;

         NOW, THEREFORE, THIS INDENTURE WITNESSETH, that in order to secure the
payment of the principal of, and the interest on, all Bonds issued and
Outstanding under this Indenture, according to their tenor, and to secure the
performance and observance of all the covenants and conditions therein and
herein set forth, and to declare the terms and conditions upon and subject to
which the Bonds are to be issued and received, and for and in consideration of
the premises and of the mutual covenants herein contained and of the purchase
and acceptance of the Bonds by the holders thereof, and for other valuable
consideration, the receipt thereof is hereby acknowledged, the Authority
covenants and agrees with the Trustee, for the equal and proportionate benefit
of the respective holders from time to time of the Bonds, as follows:

                                    ARTICLE I

                                   DEFINITIONS

         Section 1.01. Definitions. Unless the context otherwise requires, the
terms defined in this Section 1.01 shall, for all purposes of this Indenture and
of the Agreement and of any indenture supplemental hereto or agreement
supplemental thereto, have the meanings herein specified, as follows:

         "Act" means the California Pollution Control Financing Authority Act,
constituting Division 27 of the California Health and Safety Code, as amended
and supplemented to the date hereof.

         "Act of Bankruptcy" means any of the following with respect to any
person: (a) the commencement by such person of a voluntary case under the
federal bankruptcy laws, as now in effect or hereafter amended, or any other
applicable federal or state bankruptcy, insolvency or similar laws, or (b)
failure by such person to timely controvert the filing of a petition with a
court having jurisdiction over such person to commence an involuntary case
against such person under the federal bankruptcy laws, as now in effect or
hereafter amended, or any other applicable federal or state bankruptcy,
insolvency or similar laws, or (c) such person shall admit in writing its
inability to pay its debts generally as they become due, or (d) a receiver,
trustee, custodian or liquidator of such person or such person's assets shall be
appointed in any proceeding brought against the person or such person's assets,
or (e) assignment by such person for the benefit of its creditors, or (f) the
entry by such person into an agreement of composition with its creditors.

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         "Agreement" means the Loan Agreement, of even date herewith, between
the Authority and the Borrower and relating to the loan of the proceeds of the
Bonds, as originally executed or as it may from time to time be supplemented or
amended.

         "Amendment" means any amendment or modification of any Document.

         "Authority" means the California Pollution Control Financing Authority,
and any successor to its functions.

         "Authorized Authority Representative" means the Executive Director of
the Authority, the Deputy Executive Director of the Authority, or any person who
at the time and from time to time may be designated by the Executive Director of
the Authority or the Deputy Executive Director of the Authority by written
certificate furnished to the Trustee and the Borrower, as a person authorized to
act on behalf of the Authority.

         "Authorized Borrower Representative" means any person who at the time
and from time to time may be designated, by written certificate furnished to the
Authority and the Trustee, as a person authorized to act on behalf of the
Borrower. Such certificate shall contain the specimen signature of such person,
shall be signed on behalf of the Borrower by any officer of the Borrower and may
designate an alternate or alternates.

         "Authorized Denomination" means $1,000,000 or any multiple of $5,000
above that amount, until such time (if any) as a Rating Agency assigns a Single
A Rating to the Bonds, in which case "Authorized Denominations" means $100,000
or any multiple of $5,000 in excess of that amount.

         "Bankruptcy Code" means Title 11 of the United States Code, as amended.

         "Beneficial Owner" means, with respect any Book-Entry Bond, the
beneficial owner of such Bond as determined in accordance with the applicable
rules of DTC.

         "Bond Counsel" means any attorney at law or firm of attorneys, of
nationally recognized standing in matters pertaining to the validity of, and
exclusion from gross income for federal tax purposes of interest on, bonds
issued by states and political subdivisions, acceptable to the Trustee and duly
admitted to practice law before the highest court of any state of the United
States, but shall not include counsel for the Borrower.

         "Bond Fund" means the fund by that name established pursuant to Section
5.02 hereof.

         "Bond Placement Agreement" means the Bond Placement Agreement, dated
July 2, 1997, among the Authority, the Treasurer

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of the State, the Borrower and the Placement Agent for the Bonds named therein,
relating to the purchase from the Authority and the placement of the Bonds with
the purchasers thereof.

         "Bond Proceeds Fund" means the fund by that name established pursuant
to Section 3.02 hereof.

         "Bonds" means the bonds designated as provided in Section 2.01(a)
hereof, authorized and issued hereunder in an aggregate principal amount not to
exceed $19,500,000.

         "Book-Entry Bonds" means any Bonds which are then held in book-entry
form as provided in Section 2.01(e) hereof.

         "Borrower" means (i) Laidlaw Environmental Services, Inc., a Delaware
corporation and its successors and assigns, and (ii) any surviving, resulting or
transferee corporation as provided in Section 5.2 of the Agreement.

         "Business Day" means a day on which banks located in the cities in
which the Principal Offices of the Trustee, the Registrar and the Paying Agent
are located, are not required or authorized to be closed and on which the New
York Stock Exchange is not closed.

         "Certificate of the Authority" means a certificate signed by an
Authorized Authority Representative. If and to the extent required by the
provisions of Section 1.04 hereof, each Certificate of the Authority shall
include the statements provided for in Section 1.04 hereof.

         "Certificate of the Borrower" means a certificate signed by an
Authorized Borrower Representative. If and to the extent required by the
provisions of Section 1.04 hereof, each Certificate of the Borrower shall
include the statements provided for in Section 1.04 hereof.

         "Certified Resolution" means a copy of a resolution or ordinance of the
Authority certified by the Executive Director or Deputy Executive Director of
the Authority to have been duly adopted by the Authority and to be in full force
and effect on the date of such certification.

         "Code" means the Internal Revenue Code of 1986, as amended.

         "Dated Date" means July 1, 1997.

         "Determination of Taxability" means a determination that, due to the
untruth or inaccuracy of any representation or warranty made by the Borrower in
the Agreement or the breach of any covenant or warranty of the Borrower
contained in the Agreement, interest on the Bonds, or any of them, is determined
not to be Tax-Exempt by a final administrative determination of the Internal
Revenue Service or a final judicial decision of a

                                        5
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court of competent jurisdiction in a proceeding of which the Borrower received
notice and was afforded an opportunity to participate to the full extent
permitted by law. A determination or decision will not be considered final for
purposes of the preceding sentence unless (A) the Authority or the holder or
holders of the Bonds involved in the proceeding in which the issue is raised (i)
shall have given the Borrower and the Trustee prompt written notice of the
commencement thereof, and (ii) shall have offered the Borrower the opportunity
to control the proceeding; provided that the Borrower agrees to pay all expenses
in connection therewith and to indemnify such holder or holders against all
liability for such expenses (except that any such holder may engage separate
counsel, and the Borrower shall not be liable for the fees or expenses of such
counsel); and (B) such proceeding shall not be subject to a further right of
appeal or shall not have been timely appealed.

         "DTC" means The Depository Trust Company and its successors and
assigns.

         "DTC Participants" means those broker-dealers, banks and other
financial institutions from time to time for which DTC holds Bonds as securities
depository.

         "Electronic" notice means notice through a time-sharing terminal.

         "Event of Default" as used with respect to this Indenture has the
meaning specified in Section 7.01 hereof, and as used with respect to the
Agreement has the meaning specified in Section 6.1 thereof.

         "Facility" means either or both, as context may require, the Kern
County Hazardous Waste Facility located in Buttonwillow, Kern County, California
and the Imperial Valley Hazardous Waste Facility located in Westmoreland,
Imperial County, California, and more fully described in Exhibit A to the
Agreement, at which sites the 1992 Project is located.

         "Government Obligations" means bonds, notes, certificates of
indebtedness, treasury bills or other securities constituting direct obligations
of, or obligations the full and timely payment of which is guaranteed by, the
United States of America, or securities evidencing ownership interests in such
obligations or in specified portions thereof (which may consist of specific
portions of the principal of or interest on such obligations).

         The term "holder" or "Bondholder" means the registered owner of any
Bond.

         "Indenture" means this Indenture of Trust, as originally executed or as
it may from time to time be supplemented, modified or amended by any
supplemental indenture entered into pursuant to the provisions hereof.

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         "Information Services" means Financial Information, Inc.'s " Called
Bond Service," 30 Montgomery Street, 10th Floor, Jersey City, New Jersey 07302,
Attention: Editor; Kenny Information Services' "Called Bond Service," 65
Broadway, 16th Floor, New York, New York 10006; Moody's "Municipal and
Government," 99 Church Street, 8th Floor, New York, New York 10007, Attention:
Municipal News Reports; the Municipal Securities Rulemaking Board, CDI Pilot,
1640 King Street, Suite 300, Alexandria, Virginia 22314; and Standard and Poor's
"Called Bond Record," 25 Broadway, 3rd Floor, New York, New York 10004; or, in
accordance with then-current guidelines of the Securities and Exchange
Commission, such other addresses and/or such other services providing
information with respect to called bonds, or no such services, as the Borrower
may designate in a Certificate of the Borrower delivered to the Trustee.

         "Interest Payment Date" means each July 1 and January 1, commencing
January 1, 1998, and the final maturity date of the Bonds.

         "Interim Loan" has the meaning set forth in the recitals to this
Indenture.

         "Investment Securities" means any of the following: (1) Government
Obligations; (2) obligations, debentures, notes or other evidence of
indebtedness issued or guaranteed by any of the following: Banks for
Cooperatives, Federal Intermediate Credit Banks, Federal Housing Finance Board,
Export-Import Bank of the United States, Federal Financing Bank, Federal Land
Banks, Federal Farm Credit Bank, Government National Mortgage Association,
Farmer's Home Administration, Federal Home Loan Mortgage Corporation or Federal
Housing Administration; (3) obligations of any state or local government the
interest on which is Tax-Exempt for which a nationally recognized rating service
is maintaining a rating within the top two ratings of such rating service; (4)
repurchase agreements with reputable financial institutions fully secured by
collateral security actually delivered to the Trustee described in clauses (1)
or (2) of this definition continuously having a market value at least equal to
the amount so invested; (5) bankers' acceptances issued by a bank rated Aa or
better by Moody's or rated AA or better by Standard & Poor's and eligible for
purchase by the Federal Reserve Bank (which may include the Trustee and its
affiliates); (6) interest-bearing demand or time deposits (including
certificates of deposit) in banks (including the Trustee and its affiliates) and
savings and loan associations, provided such deposits are (a) secured at all
times, in the manner and to the extent provided by law, by collateral security
(described in clauses (1) or (2) of this definition) of a market value of no
less than the amount of moneys so invested or (b) with banks (including the
Trustee and its affiliates) or savings and loan associations having a combined
capital and surplus of at least one hundred million dollars ($100,000,000) or
(c) fully insured by the Federal Deposit Insurance Corporation or the Federal

 <PAGE>

Savings and Loan Insurance Corporation; (7) investment in or shares of any
"regulated investment company" within the meaning of Section 851(a) of the Code,
the assets of which are securities or investments described in (1) through (6)
above (except for any rating requirement); and (8) units of a money-market fund
or portfolio restricted to obligations issued by, or guaranteed by the full
faith and credit of, the United States of America.

         "Issue Date" means July 9, 1997.

         "Moody's" means Moody's Investors Service, a corporation organized and
existing under the laws of the State of Delaware, its successors and assigns.

         "1992 Project" means those facilities, including real property,
structures, buildings, fixtures or equipment, described in Exhibit A to the
Agreement, as it may be amended from time to time, which facilities were
financed or refinanced, in whole or in part, from the proceeds of the sale of
the Prior Bonds, and any real property, structures, buildings, fixtures or
equipment acquired in substitution for, as a renewal or replacement of, or a
modification or improvement to, all or any part of the facilities described in
said Exhibit A.

         "Notice by Mail" or "notice" of any action or condition "by Mail" shall
mean a written notice meeting the requirements of this Indenture mailed by first
class mail to the holders of specified Bonds, at the addresses shown on the
registration books maintained pursuant to Section 2.04 hereof.

         "NRMSIR" means a nationally recognized municipal securities information
repository recognized by the Securities and Exchange Commission pursuant to Rule
15c2-12. The name and address of each NRMSIR on the date of this Indenture are
as follows: Bloomberg Municipal Repository, P.O. Box 840, Princeton, New Jersey
08542-0840, Phone: (609) 279-3200, Fax: (609) 279-5963; Thomson NRMSIR,
Secondary Market Disclosure, 395 Hudson Street, 3rd Floor, New York, New York
10014, Phone: (212) 807-5001, Fax: (212) 989-2078; JJ Kenny Information Systems,
The Repository, 65 Broadway, 16th Floor, New York, New York 10006, Phone: (212)
770-4568, Fax: (212) 707-7994; Moody's NRMSIR, Public Finance Information
Center, 99 Church Street, New York, New York 10007, Phone: (800) 339-6306, Fax:
(212) 553-1460; Disclosure Inc., Commercial Indexing, 5161 River Road, Bethesda,
Maryland 20816, Attention Document Acquisition/Municipal Securities, Phone:
(301) 951-1450, Fax: (301) 718-2329; and RR Donnelley Financial, Attention:
Municipal Securities Disclosure Archive, 559 Main Street, Hudson, Massachusetts
01749, Phone: (800) 580-3670, Fax: (508) 562-1969.

         "Opinion of Counsel" means a written opinion of counsel (who may be
counsel for the Borrower) acceptable to the Trustee, the Authority and the
Borrower. If and to the extent required by

                                        8
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the provisions of Section 1.04, each Opinion of Counsel shall include the
statements provided for in Section 1.04.

         "Other Company Debt" means (i) any debt of the Borrower or its
subsidiaries on a parity with or superior to the Bonds, which is secured by
assets of the Borrower or any of its subsidiaries (including, but not limited
to, up to $650,000,000 in credit facilities given by a consortium of banks and
other financial institutions to the Borrower as of the Issue Date, or
replacement thereof) and (ii) the loan agreements and/or guaranties relating to
$20,000,000 aggregate principal amount of Carbon County, Utah Solid Waste
Disposal Refunding Revenue Bonds (Laidlaw Environmental Services, Inc.) 1997
Series A and $47,500,000 aggregate principal amount of Tooele County, Utah
Pollution Control Refunding Revenue Bonds (Laidlaw Environmental Services, Inc.)
1997 Series A.

         "Outstanding," when used as of any particular time with reference to
Bonds (subject to the provisions of Section 11.06(e)), means all Bonds
theretofore authenticated and delivered by the Registrar under this Indenture
except:

         (a)      Bonds theretofore cancelled by the Registrar or surrendered to
the Registrar for cancellation;

         (b)      Bonds in lieu of or in substitution for which other Bonds
shall have been authenticated and delivered by the Registrar pursuant to the
terms of Section 2.06; and

         (c)      Bonds with respect to which the liability of the Authority and
the Borrower have been discharged to the extent provided in, and pursuant to the
requirements of, Section 10.02.

         "Paying Agent" means any paying agent appointed as provided in Section
6.03 hereof, or any successor thereto.

         The term "person" means an individual, a corporation, a partnership, a
limited liability company, a trust, an unincorporated organization or a
government or any agency or political subdivision thereof.

         "Principal Office" (i) of the Registrar or the Paying Agent means the
office thereof designated in writing by the Registrar or the Paying Agent,
as the case may be, to the Authority, the Trustee and the Borrower, which
initially shall be located in Salt Lake City, Utah at the address set forth in
Section 11.05 hereof; and (ii) of the Trustee means the principal corporate
trust office of the Trustee designated in writing to the Authority, the
Registrar, the Paying Agent and the Borrower, which initially shall be located
in Salt Lake City, Utah at the address set forth in Section 11.05 hereof.

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<PAGE>

         "Prior Bonds" has the meaning assigned to such term in the recitals to
this Indenture.

         "Qualified Newspaper" means The Wall Street Journal or The Bond Buyer
or any other newspaper or journal containing financial news, printed in the
English language and customarily published on each Business Day, of general
circulation in New York, New York, and selected by the Borrower and designated
to the Trustee.

         "Rating Agency" means Moody's or Standard & Poor's to the extent they
then are providing or maintaining a rating on the Bonds at the request of the
Borrower, or in the event that Moody's or Standard & Poor's no longer maintains
a rating on the Bonds, any other nationally recognized rating agency then
providing or maintaining a rating on the Bonds at the request of the Borrower.

         "Rebate Fund" means the fund by that name established and held by the
Trustee in accordance with Section 6.06 hereof.

         "Rebate Requirement" has the meaning assigned to such term in the Tax
Certificate.

         "Record Date" means the fifteenth day (whether or not a Business Day)
of the month preceding such Interest Payment Date.

         "Registrar" means any registrar appointed as provided in Section 8.12
hereof, or any successor thereto.

         "Repayment Installment" means any amount that the Borrower is required
to pay to the Trustee pursuant to Section 4.2(a) of the Agreement as a repayment
of the loan made by the Authority under the Agreement.

         "Representation Letter" has the meaning specified in Section 2.01(e)
hereof.

         "Responsible Officer" of the Trustee means and includes the chairman of
the board of directors, the president, every vice president, every assistant
vice president, every trust officer, and every officer and assistant officer of
the Trustee other than those specifically above mentioned, to whom any corporate
trust matter is referred because of his or her knowledge of, and familiarity
with, a particular subject.

         "Revenues" means all rents, receipts, installment payments and other
income derived by the Authority or the Trustee under the Agreement or otherwise
in respect of the refinancing of the 1992 Project as contemplated by the
Agreement, and any income or revenue derived from the investment of any money in
any fund or account established pursuant to this Indenture (other than the
Rebate Fund and the accounts therein), including all Repayment Installments and
any other payments made by the Borrower with

                                       10
<PAGE>

respect to the Bonds pursuant to the Agreement; provided, however, that such
term shall not include payments to the Authority or the Trustee pursuant to
Sections 4.2(c), 4.2(d), 5.6, 6.3, 8.2 and 8.3 of the Agreement or any amounts
on deposit in the Rebate Fund or accounts therein.

         "Rule 15c2-12" means Rule 15c2-12 adopted by the Securities and
Exchange Commission under the Securities Exchange Act of 1934, as amended.

         "Securities Depositories" means The Depository Trust Company, 711
Stewart Avenue, Garden City, New York 11530, Fax-(516) 227-4039 or 4190; Midwest
Securities Trust Company, Capital Structures-Call Notification, 440 South
LaSalle Street, Chicago, Illinois 60605, Fax-(312) 663-2343; Philadelphia
Depository Trust Company, Reorganization Division, 1900 Market Street,
Philadelphia, Pennsylvania 19103, Attention: Bond Department, Fax-(215)
496-5058; or, in accordance with then-current guidelines of the Securities and
Exchange Commission, such other addresses and/or such other securities
depositories, or no such depositories, as the Authority may designate in a
Certificate of the Authority delivered to the Trustee.

         "SID" means the state information depository, if any, of the State
recognized by the Securities and Exchange Commission pursuant to Rule 15c2-12.

         "Single A Rating" means a rating with the designation of A or higher,
has been assigned to the Bonds by either one or both of Standard & Poor's or
Moody's.

         "Standard & Poor's" means Standard & Poor's Ratings Services, A
Division of The McGraw-Hill Companies, Inc., a corporation organized and
existing under the laws of the State of New York, its successors and assigns.

         "State" means the State of California.

         The term "supplemental indenture" or "indenture supplemental hereto"
means any indenture hereafter duly authorized and entered into between the
Authority and the Trustee in accordance with the provisions of this Indenture.

         "Tax Certificate" means the Tax Certificate and Agreement, dated as of
the Issue Date, by and between the Authority and the Borrower, as the same may
be amended from time to time.

         "Tax-Exempt" means, with respect to interest on any obligations of a
state or local government, including the Bonds, that such interest is excluded
from the gross income of the holders thereof (other than any holder who is a
"substantial user" of facilities financed with such obligations or a "related

                                       11
<PAGE>

person" within the meaning of Section 147(a) of the Code) for federal income tax
purposes, whether or not such interest is includable as an item of tax
preference or otherwise includable directly or indirectly for purposes of
calculating other tax liabilities, including any alternative minimum tax or
environmental tax under the Code.

         "Trustee" means United States National Bank of Oregon, doing business
as U.S. Bank, a national banking association organized under the laws of the
United States, and its successors and assigns or any successor trustee appointed
pursuant to Section 8.08 hereof.

         "Written Consent of the Authority," "Written Order of the Authority,"
and "Written Request of the Authority" mean, respectively, a written consent,
order or request signed by or on behalf of the Authority by an Authorized
Authority Representative.

         "Written Consent of the Borrower," "Written Order of the Borrower," and
"Written Request of the Borrower" mean, respectively, a written consent, order
or request signed by or on behalf of the Borrower by an Authorized Borrower
Representative.

         "Yield" shall have the meaning ascribed to such term by Section 148(h)
of the Code.

         Section 1.02. Number and Gender. The singular form of any word used
herein, including the terms defined in Section 1.01, shall include the plural,
and vice versa. The use herein of a word of any gender shall include all
genders.

         Section 1.03. Articles, Sections, Etc. All references herein to
"Articles," "Sections" and other subdivisions are to the corresponding Articles,
Sections or subdivisions of this Indenture as originally executed; and the words
"herein," "hereof," "hereunder" and other words of similar import refer to this
Indenture as a whole and not to any particular Article, Section or subdivision
hereof. The headings or titles of the several Articles and Sections hereof, and
any table of contents appended to copies hereof, shall be solely for convenience
of reference and shall not affect the meaning, construction or effect of this
Indenture.

         Section 1.04. Content of Certificates and Opinions. Every certificate
or opinion with respect to compliance with a condition or covenant provided for
in this Indenture or the Agreement (except for the certificate of cancelled
Bonds provided for in Sections 2.06, 2.07, 4.05 and 6.01 hereof) shall include
(a) a statement that the person or persons making or giving such certificate or
opinion have read such covenant or condition and the definitions herein relating
thereto; (b) 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

                                       12
<PAGE>

opinion are based; (c) a statement that, in the opinion of the signers, they
have made or caused to be made such examination or investigation as is necessary
to enable them to express an informed opinion as to whether or not such covenant
or condition has been complied with; and (d) a statement as to whether, in the
opinion of the signers, such condition or covenant has been complied with.

         Any such certificate or opinion made or given by an officer of the
Authority or the Borrower may be based, insofar as it relates to legal matters,
upon a certificate or opinion of or representations by counsel, unless such
officer knows that the certificate or opinion or representations with respect to
the matters upon which his or her certificate or opinion may be based as
aforesaid are erroneous, or in the exercise of reasonable care should have known
that the same were erroneous. Any such certificate or opinion made or given by
counsel may be based, insofar as it relates to factual matters (with respect to
which information is in the possession of the Authority or the Borrower), upon
the certificate or opinion of or representations by an officer of the Authority
or the Borrower, as applicable, unless such counsel knows that the certificate
or opinion or representations with respect to the matters upon which his or her
opinion may be based as aforesaid are erroneous, or in the exercise of
reasonable care should have known that the same were erroneous.

                                   ARTICLE II

                                    THE BONDS

         Section 2.01. Authorization and Terms of Bonds.

         (a)      Authorization. Bonds designated as "California Pollution
Control Financing Authority Pollution Control Refunding Revenue Bonds (Laidlaw
Environmental Services, Inc.) 1997 Series A", may be issued under this
Indenture. The aggregate principal amount of Bonds which may be issued and
Outstanding under this Indenture shall not exceed Nineteen Million Five Hundred
Thousand Dollars ($19,500,000), exclusive of Bonds executed and authenticated as
provided in Section 2.06.

         (b)      General Terms. The Bonds shall be issued as fully registered
Bonds, without coupons, in Authorized Denominations and shall all be dated as of
the Dated Date. The Bonds shall mature upon the terms and conditions hereinafter
set forth, on July 1, 2007.

         The Bonds shall bear the letter prefix "RA-" and be numbered
consecutively from 1 upward. Each Bond shall bear interest from the last date to
which interest has been paid in full or duly provided for on such Bond, or, if
no interest has been paid or duly provided for on such Bond, from the Dated
Date.

                                       13
<PAGE>

Payment of the interest on any Bond shall be made to the person appearing on the
bond registration books of the Registrar as the registered holder thereof as of
the close of business on the Record Date, such interest to be paid by the Paying
Agent to such registered holder (i) in the event such Bond is a Book-Entry Bond,
in immediately available funds on the Interest Payment Date in accordance with
the Representation Letter; and (ii) in the event such Bond is not a Book-Entry
Bond, (A) in immediately available funds (by wire transfer or by deposit to the
account of the holder of any such Bond if such account is maintained with the
Paying Agent), according to the instructions given by such holder to the
Registrar or (B) in all other cases, by check mailed by first class mail to the
holder at such holder's address as it appears as of the Record Date on the
registration books of the Registrar; except, in each case, that, if and to the
extent that there shall be a default in the payment of the interest due on such
Interest Payment Date, such defaulted interest shall be paid to the holders in
whose name any such Bonds are registered as of a special record date to be fixed
by the Trustee, notice of which shall be given to such holders not less than ten
(10) days prior thereto. The principal of the Bonds shall be payable upon
surrender thereof in lawful money of the United States of America at the
Principal Office of the Paying Agent.

         (c)      Interest Rate. The Bonds shall bear interest until final
payment of the principal or redemption price thereof shall have been made in
accordance with the provisions hereof, whether at maturity, upon redemption or
otherwise. Interest on the Bonds shall be computed upon the basis of a 360-day
year, consisting of twelve 30-day months. The Bonds shall bear interest at the
rate of 6.70% per annum.

         (d)      Form of Bonds. The Bonds may be engraved, printed,
lithographed or typewritten, shall be in Authorized Denominations and may
contain such references to any of the provisions of this Indenture as may be
appropriate. The Bonds and the certificate of authentication to be executed
thereon shall be in substantially the form attached hereto as Exhibit A, with
such appropriate variations, omissions and insertions as are permitted or
required by this Indenture. Pursuant to recommendations promulgated by the
Committee on Uniform Security Identification Procedures, "CUSIP" numbers may be
printed on the Bonds. The Bonds may bear such endorsement or legend relating
thereto as may be required to conform to usage or law with respect thereto. If
appropriate, the Bonds may be printed with a portion of the text printed on the
reverse side thereof and with a legend printed on the front referring to such
text to the following effect: "Reference is hereby made to the further
provisions of this Bond set forth on the back hereof and such further provisions
are hereby incorporated by reference as if set forth here in full."

         (e)      Book-Entry System. Unless otherwise determined by the
Authority, the Bonds shall be issued in the form of one or more

                                       14
<PAGE>

separate single certificated fully registered Bond or Bonds, registered in the
name of Cede & Co., as nominee of DTC, or any successor nominee (the "Nominee").
Except as provided in paragraph (iii) below, all of the Outstanding Bonds shall
be so registered in the registration books kept by the Registrar, and the
provisions of this Section 2.01(e) shall apply thereto.

         (i)      The Authority, the Borrower, the Paying Agent, the Registrar
and the Trustee shall have no responsibility or obligation to any DTC
Participant or to any Beneficial Owner, except as otherwise expressly provided
herein. Without limiting the immediately preceding sentence, the Authority, the
Borrower, the Paying Agent, the Registrar and the Trustee shall have no
responsibility or obligation with respect to (1) the accuracy of the records of
DTC, the Nominee or any DTC Participant with respect to any ownership interest
in the Bonds, (2) the delivery to any DTC Participant or any other person, other
than a Bondholder as shown in the registration books kept by the Registrar, of
any notice with respect to the Bonds, including any notice of redemption or (3)
the payment to any DTC Participant or any other person, other than a Bondholder,
as shown in the registration books kept by the Registrar, of any amount with
respect to principal of or interest on the Bonds. The Paying Agent shall pay all
principal of, and interest on the Bonds only to or upon the order of the
respective Bondholders, as shown in the registration books kept by the
Registrar, or their respective attorneys duly authorized in writing, and all
such payments shall be valid and effective to fully satisfy and discharge the
Authority's obligations with respect to payment of principal of, and interest on
the Bonds to the extent of the sum or sums so paid. The Authority, the Borrower,
the Paying Agent, the Registrar and the Trustee may treat and consider the
person in whose name each Bond is registered in the registration books kept by
the Registrar as the holder and absolute owner of such Bond for the purpose of
payment of principal and interest with respect to such Bond, for the purpose of
giving notices of redemption and other matters with respect to such Bond, for
the purpose of registering transfers with respect to such Bond, and for all
other purposes whatsoever.

         (ii)     No person other than a Bondholder, as shown in the
registration books kept by the Registrar, shall receive a certificated Bond
evidencing the obligation of the Authority to make payments of principal, and
interest pursuant to this Indenture.

         (iii)    The Authority, the Paying Agent, the Registrar and the Trustee
shall, if not previously on file, execute and deliver to DTC a letter of
representation in customary form with respect to the Bonds (the "Representation
Letter"), but such Representation Letter shall not in any way limit the
provisions of the foregoing paragraph (i) or in any other way impose upon the
Authority any obligation whatsoever with respect to persons having interests in
the Bonds other than the Bondholders, as

                                       15
<PAGE>

shown on the registration books kept by the Registrar. The Trustee and the
Paying Agent shall take all action necessary for all representations of the
Authority in the Representation Letter with respect to the Trustee and the
Paying Agent to be complied with at all times.

         (iv)     The Authority, with the consent of the Borrower, may, and upon
request of the Borrower shall, terminate the services of DTC with respect to the
Bonds. DTC may determine to discontinue providing its services with respect to
the Bonds at any time by giving written notice and all relevant information
on the Beneficial Owners of the Bonds to the Authority, the Borrower and the
Trustee and discharging its responsibilities with respect thereto under
applicable law. Upon the discontinuance or termination of the services of DTC
with respect to the Bonds, unless a substitute securities depository is
appointed by the Authority (with the consent, or at the request, of the
Borrower) to undertake the functions of DTC hereunder, the Authority, at the
expense of the Borrower, is obligated to deliver Bond certificates to the
Beneficial Owners of such Bonds, as described in this Indenture, and such Bonds
shall no longer be restricted to being registered in the registration books kept
by the Registrar in the name of the Nominee, but may be registered in whatever
name or names Bondholders transferring or exchanging such Bonds shall designate,
in accordance with the provisions of this Indenture.

         (v)      So long as any Bond is registered in the name of the Nominee,
all payments with respect to principal and interest on such Bond and all notices
with respect to such Bond shall be made and given, respectively, in the manner
provided in the Representation Letter. Bondholders shall have no lien or
security interest in any rebate or refund paid by DTC to the Paying Agent which
arises from the payment by the Paying Agent of principal of, or interest on the
Bonds in immediately available funds to DTC.

         Section 2.02. Execution of Bonds. The Bonds shall be signed in the name
and on behalf of the Authority with the manual or facsimile signature of its
Chairman and attested by the manual or facsimile signature of its Executive
Director or Deputy Executive Director, under seal of the Authority. Such seal
may be in the form of a facsimile of the Authority's seal and may be imprinted
or impressed upon the Bonds. The Bonds shall then be delivered to the Registrar
for authentication by the Registrar, as the case may be; provided that upon
initial issuance the Bonds shall be authenticated by the Registrar. In case any
officer who shall have signed any of the Bonds shall cease to be such officer
before the Bonds so signed or attested shall have been authenticated or
delivered by the Registrar or issued by the Authority, such Bonds may
nevertheless be authenticated, delivered and issued and, upon such
authentication, delivery and issuance, shall be as binding upon the Authority as
though those who signed and attested the same had continued to be such

                                       16
<PAGE>

officers of the Authority. Also, any Bond may be signed on behalf of the
Authority by such persons as on the actual date of the execution of such Bond
shall be the proper officers although on the nominal date of such Bond any such
person shall not have been such officer.

         Only such of the Bonds as shall bear thereon a certificate of
authentication in the form recited in Exhibit A hereto, manually executed by the
Registrar, shall be valid or obligatory for any purpose or entitled to the
benefits of this Indenture, and such certificate of the Registrar shall be
conclusive evidence that the Bonds so authenticated have been duly authenticated
and delivered hereunder and are entitled to the benefits of this Indenture. Upon
authentication of any Bond, the Registrar shall set forth on such Bond the date
of such authentication.

         Section 2.03. Transfer and Exchange of Bonds. Registration of any Bond
may, in accordance with the terms of this Indenture, be transferred, upon the
books of the Registrar required to be kept pursuant to the provisions of Section
2.04, by the person in whose name it is registered, in person or by his duly
authorized attorney, upon surrender of such Bond for cancellation, accompanied
by a written instrument of transfer in a form approved by the Registrar, duly
executed. Whenever any Bond shall be surrendered for registration of transfer,
the Authority shall execute and the Registrar shall authenticate and deliver a
new Bond or Bonds of the same tenor of Authorized Denominations. No registration
of transfer of Bonds upon the books of the Registrar required to be kept
pursuant to the provisions of Section 2.04 hereof shall be required to be made
during the period after any Record Date and prior to the related Interest
Payment Date or during the period of fifteen (15) days next preceding the date
on which the Trustee gives any notice of redemption, nor shall any registration
of transfer of Bonds called for redemption be required.

         Bonds may be exchanged at the Principal Office of the Registrar for a
like aggregate principal amount of Bonds of the same tenor of Authorized
Denominations. The Registrar shall require the payment by the Bondholder
requesting such exchange of any tax or other governmental charge required to be
paid with respect to such exchange, and there shall be no other charge to any
Bondholders for any such exchange. No exchange of Bonds shall be required to be
made during the period after any Record Date and prior to the related Interest
Payment Date or during the period of fifteen (15) days next preceding the date
on which the Trustee gives notice of redemption, nor shall any exchange of Bonds
called for redemption be required.

         Section 2.04. Bond Register. The Registrar will keep or cause to be
kept at its Principal Office sufficient books for the registration and the
registration of transfer of the Bonds, which shall at all times, during regular
business hours, be open to

                                       17
<PAGE>

inspection by the Authority, the Trustee and the Borrower; and, upon
presentation for such purpose, the Registrar shall, under such reasonable
regulations as it may prescribe, register the transfer or cause to be registered
the transfer, on said books, of Bonds as hereinbefore provided.

         Section 2.05.  Reserved.

         Section 2.06. Bonds Mutilated, Lost, Destroyed or Stolen. If any Bond
shall become mutilated, the Authority, upon the request and at the expense of
the holder of said Bond, shall execute, and the Registrar shall thereupon
authenticate and deliver, a new Bond of like tenor and number in exchange and
substitution for the Bond so mutilated, but only upon surrender to the Registrar
of the Bonds so mutilated. Every mutilated Bond so surrendered to the Registrar
shall be cancelled by it and destroyed and, upon the written request of the
Authority, a certificate evidencing such destruction shall be delivered to the
Authority, with a copy to the Borrower. If any Bond issued hereunder shall be
lost, destroyed or stolen, evidence of such loss, destruction or theft may be
submitted to the Authority, the Borrower and the Registrar, and if such evidence
be satisfactory to them and indemnity satisfactory to them shall be given by or
on behalf of the holder of such lost, destroyed or stolen Bond, the Authority,
at the expense of the holder, shall execute, and the Registrar shall thereupon
authenticate and deliver, a new Bond of like tenor in lieu of and in
substitution for the Bond so lost, destroyed or stolen (or if any such Bond
shall have matured or shall be about to mature, instead of issuing a substitute
Bond the Registrar may pay the same without surrender thereof). The Authority
may require payment of a reasonable fee for each new Bond issued under this
Section and payment of the expenses which may be incurred by the Authority and
the Registrar. Any Bond issued under the provisions of this Section in lieu of
any Bond mutilated or alleged to be lost, destroyed or stolen shall constitute
an original additional contractual obligation on the part of the Authority
whether or not the Bond mutilated or so alleged to be lost, destroyed or stolen
shall be at any time enforceable by anyone, and shall be equally and
proportionately entitled to the benefits of this Indenture with all other Bonds
secured by this Indenture.

         Section 2.07. Disposition of Cancelled Bonds. When and as paid in full,
all Bonds, if any, shall be delivered to the Trustee, who shall forthwith cancel
such Bonds and deliver a certificate evidencing such cancellation to the
Authority and the Borrower. The Trustee may destroy or retain such cancelled
Bonds.

                                       18
<PAGE>

         Section 2.08. CUSIP Numbers. As provided in Section 2.01(d) of this
Indenture, the Authority in issuing the Bonds 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 of Bonds; provided that any such
notice may state that no representation is made as to the correctness of such
numbers either as printed on the Bonds or as contained in any notice of a
redemption and that reliance may be placed only on the other identification
numbers printed on the Bonds, and any such redemption shall not be affected by
any defect in or omission of such CUSIP numbers.

                                   ARTICLE III

                                ISSUANCE OF BONDS

         Section 3.01. Authentication and Delivery of Bonds. Forthwith upon the
execution and delivery of this Indenture, upon the execution of the Bonds by the
Authority and delivery thereof to the Registrar, as hereinabove provided, and
without any further action on the part of the Authority, the Registrar shall
authenticate the Bonds in an aggregate principal amount of Nineteen Million Five
Hundred Thousand Dollars ($19,500,000) and shall deliver the Bonds to or upon
the Written Order of the Authority.

         Section 3.02. Application of Proceeds of Bonds. The proceeds received
by the Authority from the sale of the Bonds in the amount of $19,500,000 shall
be deposited with the Trustee in the Bond Proceeds Fund, which the Trustee shall
establish hereunder and hold in trust. The Trustee shall transfer such money in
the Bond Proceeds Fund upon Written Order of the Borrower to repay the Interim
Loan and thereby refunding the Prior Bonds.

         Upon completion of the foregoing transfer, the Bond Proceeds Fund shall
close.

                                   ARTICLE IV

                               REDEMPTION OF BONDS

         Section 4.01. Redemption of Bonds. The Bonds are subject to redemption
if and to the extent the Borrower is entitled or required to make and makes a
prepayment pursuant to Article VII of the Agreement. The Trustee shall not give
notice of any optional redemption under Section 4.01(a) hereof unless the
Borrower has so directed in accordance with Section 7.5 of the Agreement. In the
event of a failure by the Borrower to give a notice of mandatory prepayment
under such Section 7.5, such notice may be given by the Authority, the Trustee,
or any holder

                                       19
<PAGE>

or holders of ten percent (10%) or more in aggregate principal amount of the
Outstanding Bonds.

         The Bonds shall be redeemed upon the following terms:

         (a)      Redemption Upon Optional Prepayment - Extraordinary Events.

         The Bonds shall be redeemed in whole or in part, and if in part by lot,
at any time at a redemption price equal to 100% of the principal amount thereof
plus accrued interest to the redemption date upon the occurrence of any one of
the following events and receipt by the Trustee of a written notice from the
Borrower stating that such event has occurred and that the Borrower therefore
intends to exercise its option to prepay the payments due under the Agreement
in whole or in part pursuant to Section 7.2 of the Agreement and thereby effect
the redemption of Bonds in whole or in part to the extent of such prepayments:

       (1)      All or part of the Facility at which a portion of the 1992
  Project is located shall have been damaged or destroyed to such an extent
  that, in the opinion of the Borrower (expressed in a certificate
  filed with the Authority and the Trustee), (i) the Facility or such
  affected portion could not reasonably be restored within a period of four
  (4) months to the condition thereof immediately preceding such damage or
  destruction, and the Borrower will be prevented, or is likely to be
  prevented for a period of four (4) consecutive months or more, from
  carrying on all or substantially all of its normal operation of the
  Facility, or (ii) the cost of restoration of the Facility or such affected
  portion will be substantially in excess of the net proceeds of insurance
  thereon.

       (2)      Title to, or the temporary use of, all or a part of the
  Facility at which a portion of the 1992 Project is located shall have been
  taken under the exercise of the power of eminent domain.

       (3)      Changes in economic availability of raw materials, operating
  supplies or facilities necessary to operate all or a part of the Facility
  at which a portion of the 1992 Project is located or technological or
  other changes which make the continued operation of the Facility or such
  affected portion, uneconomical in the opinion of the Borrower (expressed in
  a certificate filed with the Authority and the Trustee) shall have occurred
  and which shall have resulted in a cessation of all or substantially all of
  the Borrower's normal operations of the Facility.

       (4)      Unreasonable burdens or excessive liabilities shall have been
  imposed upon the Authority or the Borrower affecting all or a part of the
  Facility at which a portion of the 1992 Project is located including,
  without limitation,

                                       20
<PAGE>

  federal, state or other ad valorem, property, income or other taxes not being
  imposed on the date of the Agreement.

  Anything in this subsection to the contrary notwithstanding, if any of the
events described above shall have occurred with respect to one of the two
Facilities, the amount of Bonds that may be redeemed shall not exceed an amount
derived by multiplying the total principal amount of the Bonds by a fraction (i)
the numerator of which is the cost of the 1992 Project at such affected Facility
or portion thereof and (ii) the denominator of which is the total cost of the
1992 Project.

         (b)      Redemption Upon Mandatory Prepayment. The Bonds shall be
subject to redemption from amounts which are required to be prepaid by the
Borrower under Section 7.3 of the Agreement, as set forth below.

         The Bonds shall be redeemed in whole on any date at a redemption price
  equal 100% of the principal amount thereof plus interest accrued to the
  redemption date upon the occurrence of a Determination of Taxability;
  provided, however, that if, in the opinion of Bond Counsel delivered to the
  Trustee, the redemption of a specified portion of such Bonds Outstanding would
  have the result that interest payable on such Bonds remaining Outstanding
  after such redemption would remain Tax-Exempt, then such Bonds shall be
  redeemed in part by lot (in Authorized Denominations), in such amount as Bond
  Counsel in such opinion shall have determined is necessary to accomplish that
  result.

         (2)      The Bonds shall be redeemed in whole at a redemption price
  equal to the principal amount thereof plus accrued interest to the redemption
  date in the event that as a result of any changes in the Constitution of the
  United States of America or the State or as a result of any legislative,
  judicial or administrative action, the Agreement shall have become void or
  unenforceable or impossible of performance in accordance with the intention
  and purposes of the parties thereto, or shall have been declared unlawful.

         (c)      Sinking Fund Redemption. The Bonds are subject to mandatory
redemption in part on each July 1 commencing July 1, 2003, from sinking fund
payments made by the Borrower, at a redemption price equal to the principal
amount of Bonds to be

                                       21
<PAGE>

redeemed as set forth in the table below, without premium, plus accrued interest
to the date of redemption:

  Sinking Fund
  Payment Date                                          Amount
    (July 1)                                           Redeemed
    --------                                           --------

       2003                                           $2,000,000
       2004                                            2,000,000
       2005                                            2,000,000
       2006                                            3,000,000
       2007*                                          10,500,000

*Maturity

         Section 4.02. Selection of Bonds for Redemption. If less than all of
the Bonds are called for redemption, the Trustee shall select the Bonds or any
given portion thereof to be redeemed from the Outstanding Bonds or such given
portion thereof not previously called for redemption, by lot. For the purpose of
any such selection the Trustee shall assign a separate number for each minimum
Authorized Denomination of each Bond of a denomination of more than such
minimum; provided that following any such selection, both the portion of such
Bond to be redeemed and the portion remaining shall be in Authorized
Denominations. The Trustee shall promptly notify the Authority and the Borrower
in writing of the numbers of the Bonds or portions thereof so selected for
redemption. Notwithstanding the foregoing, if less than all of the Bonds are to
be redeemed at any time while the Bonds are Book-Entry Bonds, selection of the
Bonds to be redeemed shall be made in accordance with customary practices of DTC
or the applicable successor depository, as the case may be.

         Section 4.03. Notice of Redemption. The Trustee, for and on behalf of
the Authority, shall give notice of any redemption by first class mail, postage
prepaid, not less than thirty (30) nor more than sixty (60) days prior to the
redemption date to (i) the registered owner of such Bond at the address shown on
the registration books of the Registrar on the date such notice is mailed; (ii)
the Securities Depositories; (iii) one or more Information Services; and (iv)
the Municipal Securities Rulemaking Board, each NRMSIR and the SID. Notice of
redemption to the Securities Depositories, the Information Services, each NRMSIR
and the SID shall be given by telecopy confirmed by first class mail. Each
notice of redemption shall state the date of such notice, the date of issue of
the Bonds to be redeemed, the redemption date, the redemption price, the place
of redemption (including the name and appropriate address or addresses of the
Paying Agent), the principal amount, the CUSIP numbers (if any) of the Bonds to
be redeemed and, if less than all, the distinctive certificate numbers of the
Bonds to be redeemed and, in the case of Bonds to be redeemed in part only, the
respective portions of the principal amount thereof to be redeemed. Each such
notice shall also state that the interest on the Bonds

                                       22
 <PAGE>

designated for redemption shall cease to accrue from and after such redemption
date and that on said date there will become due and payable on each of said
Bonds the principal amount thereof to be redeemed and the interest accrued
thereon, if any, to the redemption date and shall require that such Bonds be
then surrendered at the address or addresses of the Paying Agent specified in
the redemption notice. Notwithstanding the foregoing, failure by the Trustee to
give notice pursuant to this paragraph to any one or more of the Information
Services or the Securities Depositories or Municipal Securities Rulemaking
Board, the NRMSIRs or the SID or the insufficiency of any such notices shall not
affect the sufficiency of the proceedings for redemption. Failure to mail the
notices required by this paragraph to any registered owner of any Bonds
designated for redemption, or any defect in any notice so mailed, shall not
affect the validity of the proceedings for redemption of any other Bonds.

         If upon the expiration of sixty (60) days succeeding any redemption
date, any Bonds called for redemption shall not have been presented to the
Trustee for payment, the Trustee shall no later than ninety (90) days following
such redemption date send Notice by Mail to the holder of each Bond not so
presented. Failure to mail the notices required by this paragraph to any holder
of a Bond, or any defect in any notice so mailed, shall not affect the validity
of the proceedings for redemption of any Bonds nor impose any liability on the
Trustee.

         Section 4.04. Partial Redemption of Bonds. Upon surrender of any Bond
redeemed in part only, the Registrar shall exchange the Bond redeemed for a new
Bond of like tenor and in an Authorized Denomination without charge to the
holder in the principal amount of the portion of the Bond not redeemed. In the
event of any partial redemption of a Bond which is registered in the name of the
Nominee, DTC may elect to make a notation on the Bond certificate which reflects
the date and amount of the reduction in principal amount of said Bond in lieu of
surrendering the Bond certificate to the Registrar for exchange. The Authority,
the Trustee and the Registrar shall be fully released and discharged from all
liability upon, and to the extent of, payment of the redemption price for any
partial redemption and upon the taking of all other actions required hereunder
in connection with such redemption.

         Section 4.05. Effect of Redemption. Notice of redemption having been
duly given as aforesaid, and moneys for payment of the redemption price being
held by the Trustee, the Bonds so called for redemption shall, on the redemption
date designated in such notice, become due and payable at the redemption price
specified in such notice, interest on the Bonds so called for redemption shall
cease to accrue, said Bonds shall cease to be entitled to any lien, benefit or
security under this Indenture, and the holders of said Bonds shall have no
rights in respect thereof except to receive payment of the redemption price

                                       23
<PAGE>

thereof (including interest, if any, accrued to the redemption date), without
interest accrued on any funds held after the redemption date to pay such
redemption price.

         All Bonds fully redeemed pursuant to the provisions of this Article IV
shall upon surrender thereof be cancelled by the Trustee, who shall deliver a
certificate evidencing such cancellation to the Authority and the Borrower. The
Trustee may retain or destroy such Bonds.

                                    ARTICLE V

                                    REVENUES

         Section 5.01. Pledge of Revenues.

         (a) All of the Revenues are hereby irrevocably pledged to the punctual
payment of the principal of and interest on the Bonds, and Revenues shall not be
used for any other purpose, except as provided in the last paragraph of Section
5.02, while any of the Bonds remain Outstanding. Said pledge shall constitute a
first and exclusive lien on the Revenues for the payment of the Bonds in
accordance with the terms hereof and thereof. All Revenues shall be held in
trust for the benefit of the holders from time to time of the Bonds, but shall
nevertheless be disbursed, allocated and applied solely for the uses and
purposes set forth in Article IV and this Article V.

         (b) Reserved.

         (c) The Borrower may at its sole discretion from time to time deliver
to the Trustee such additional or other security interests permitted by this
Indenture or the Authority to secure the payment of the principal of and
interest on the Bonds and any such additional or other security delivered by the
Borrower shall be pledged to such payment, provided that the delivery of such
additional or other security does not adversely affect the Tax- Exempt status of
interest on the Bonds.

         (d) The Bonds shall not constitute a debt or liability, or a pledge of
the faith and credit, of the State, but shall be payable solely from the funds
herein provided therefor. The issuance of the Bonds shall not directly or
indirectly or contingently obligate the Authority, the State or any political
subdivision thereof to levy or pledge any form of taxation whatever therefor or
to make any appropriation for their payment.

         Section 5.02. Bond Fund. Upon the receipt thereof, the Trustee shall
deposit all Revenues in the "California Pollution Control Financing Authority
Pollution Control Refunding Revenue Bonds (Laidlaw Environmental Services, Inc.)
1997 Series A Bond Fund," which the Trustee shall establish and maintain and
hold in trust, and which shall be disbursed and applied only as

                                       24

<PAGE>

hereinafter authorized. Except as provided in this Section, Sections 5.06 and
10.03, moneys in the Bond Fund shall be used solely for the payment of the
principal of and interest on the Bonds as the same shall become due, whether at
maturity or upon redemption or acceleration or otherwise.

         The Trustee shall deposit in the Bond Fund from time to time, upon
receipt thereof, all Repayment Installments received by the Trustee from the
Borrower for deposit in the Bond Fund, any income received from the investment
of moneys on deposit in the Bond Fund and any other Revenues, including
insurance proceeds, condemnation awards and other prepayment amounts received
under the Agreement from or for the account of the Borrower.

         In making payments of principal of, and interest on the Bonds, the
Trustee shall (a) first use all available amounts held in the Bond Fund, and (b)
then use any other Revenues received by the Trustee.

         Except to the extent such moneys are required to be held for the
payment of principal of, or interest on the Bonds then due and payable or to
effect the defeasance of Bonds pursuant to Article X hereof, so long as no Event
of Default (or any event which would be an Event of Default hereunder with the
passage of time or the giving of notice) exists hereunder, on the fifth day
after each Interest Payment Date, the Trustee, unless otherwise instructed by
the Borrower, shall return to the Borrower (free and clear of the pledge and
lien of this Indenture) any moneys then on deposit in the Bond Fund or shall
deposit such funds in the Rebate Fund if so instructed by the Borrower.

         Section 5.03. Trustee Authorized to Take Actions Under the Agreement.
The Authority hereby authorizes and directs the Trustee, and the Trustee hereby
agrees, subject to Section 7.02 hereof, to take such actions as the Trustee
deems necessary to enforce the Borrower's obligation under the Agreement to make
timely payment of principal of and interest on the Bonds to the extent Bond
proceeds and other moneys in the Bond Fund are not available for such payment in
accordance with the provisions of Section 5.02 hereof.

         Section 5.04. Investment of Moneys. Subject to Section 6.06 hereof, any
moneys in any of the funds and accounts to be established by the Trustee
pursuant to this Indenture shall be invested upon the written direction of the
Borrower signed by an Authorized Borrower Representative (such direction to
specify the particular investment to be made), by the Trustee, if and to the
extent then permitted by law, in Investment Securities. In the absence of such
written direction, the Trustee shall invest solely in units of a money-market
fund or portfolio restricted to obligations issued by, or guaranteed by the full
faith and credit of, the United States of America which is rated by each Rating
Agency at least as high as the then current rating of such Rating

                                       25
<PAGE>

Agency on the Bonds if such Rating Agency is then rating the Bonds or if the
Bonds are not rated, within the top two rating categories of a nationally
recognized rating service. Moneys in any fund or account shall be invested in
Investment Securities with respect to which payments of principal thereof and
interest thereon are scheduled to be paid or are otherwise payable (including
Investment Securities payable at the option of the holder) not later than the
date on which such moneys will be required by the Trustee. Amounts held in the
Bond Fund shall be invested only in Government Obligations maturing or subject
to payment at par upon demand of the holder thereof within thirty (30) days
after the acquisition of any such investment (or on such earlier date as payment
thereunder shall be needed hereunder).

         Any interest, profit or loss on any investments of moneys in any fund
or account under this Indenture shall be credited or charged to the respective
funds from which such investments are made. The Trustee may sell or present for
redemption any obligations so purchased whenever it shall be necessary in order
to provide moneys to meet any payment, and the Trustee shall not be liable or
responsible for any loss, fee, tax or other charge resulting from any
investment, reinvestment or liquidation hereunder. Unless otherwise directed by
the Borrower, the Trustee may make any investment permitted under this Section
5.04 through or with its own commercial banking or investment departments.

         Section 5.05. Assignment to Trustee; Enforcement of Obligations. (a)
The Authority hereby transfers, assigns and sets over to the Trustee all of the
Revenues and any and all rights and privileges it has under the Agreement with
respect to the Bonds, except (i) the Authority's rights to receive any notices
under this Indenture or the Agreement, (ii) the Authority's right to receive
payments, if any, with respect to fees, expenses and indemnification and certain
other purposes under Sections 4.2(d), 4.2(e), 6.3, 8.2 and 8.3 of the Agreement
and (iii) the Authority's rights to give approvals or consents pursuant to the
Agreement, but including, without limitation, the right to collect and receive
directly all of the Revenues and the right to hold and enforce any security
interest, and any Revenues collected or received by the Authority shall be
deemed to be held, and to have been collected or received, by the Authority as
the agent of the Trustee, and shall forthwith be paid by the Authority to the
Trustee. The Trustee also shall be entitled to take all steps, actions and
proceedings reasonably necessary in its judgment (1) to enforce the terms,
covenants and conditions of, and preserve and protect the priority of its
interest in and under, the Agreement and any other security agreement with
respect to the 1992 Project or the Bonds, and (2) to assure compliance with all
covenants, agreements and conditions on the part of the Authority contained in
this Indenture with respect to the Revenues.

                                       26
<PAGE>

         Section 5.06. Repayment to Borrower. When there are no longer any Bonds
Outstanding or provision for payment of the Bonds has been made in accordance
with Article X hereof, and all fees, charges and expenses of the Trustee, the
Registrar and any Paying Agent have been paid or provided for, payment of the
full amount owing the United States Government, as determined under Section 5.6
of the Agreement, Section 6.06 hereof and the Tax Certificate, all expenses of
the Authority relating to the 1992 Project and this Indenture have been paid or
provided for, and all other amounts payable hereunder and under the Agreement
have been paid, and this Indenture has been discharged and satisfied, the
Trustee shall pay to the Borrower any amounts remaining in any fund established
and held hereunder.

                                   ARTICLE VI

                           COVENANTS OF THE AUTHORITY

         Section 6.01. Payment of Principal and Interest. The Authority shall
punctually pay, but only out of Revenues as herein provided, the principal and
the interest to become due in respect of every Bond issued hereunder at the
times and places and in the manner provided herein and in the Bonds according to
the true intent and meaning thereof. All such payments shall be made by the
Trustee as provided in Section 2.01(b). When and as paid in full, all Bonds, if
any, shall be delivered to the Trustee and shall forthwith be cancelled by the
Trustee, who shall deliver a certificate evidencing such cancellation to the
Authority and the Borrower. The Trustee may retain or destroy such cancelled
Bonds.

         Section 6.02. Extension or Funding of Claims for Interest. In order to
prevent any accumulation of claims for interest after maturity, the Authority
shall not, directly or indirectly, extend or assent to the extension of the time
for the payment of any claim for interest on any of the Bonds, and shall not,
directly or indirectly, be a party to or approve any such arrangement by
purchasing or funding such claims or in any other manner. In case any such claim
for interest shall be extended or funded, whether or not with the consent of the
Authority, such claim for interest so extended or funded shall not be entitled,
in case of default hereunder, to the benefits of this Indenture, except subject
to the prior payment in full of the principal of all of the Bonds then
Outstanding and of all claims for interest which shall not have been so extended
or funded.

         Section 6.03. Paying Agents. The Authority, with the written approval
of the Trustee and the Borrower, may appoint and at all times have one or more
Paying Agents (which shall meet the qualifications of the Trustee set forth in
Section 8.07 hereof) in such place or places as the Borrower may designate, for
the payment of the principal of, and the interest on, the Bonds. All provisions
of Article VIII hereof which apply to the Trustee

                                       27
<PAGE>

shall also apply to any Paying Agent appointed hereunder. It shall be the duty
of the Trustee to make such arrangements with any such Paying Agent as may be
necessary to assure, to the extent of the moneys held by the Trustee for such
payment, the prompt payment of the principal of and interest on the Bonds
presented at either place of payment. The Paying Agent initially appointed
hereunder is the Trustee.

         Section 6.04. Preservation of Revenues. The Authority shall not waive
any provision of the Agreement or take any action to interfere with or impair
the pledge and assignment hereunder of Revenues and the assignment to the
Trustee of rights under the Agreement, or the Trustee's enforcement of any
rights thereunder, without the prior written consent of the Trustee. The Trustee
may give such written consent, and may itself take any such action, or consent
to any Amendment, only in accordance with the provisions of Article IX hereof.

         Section 6.05. Compliance with Indenture. The Authority shall not issue,
or permit to be issued, any Bonds secured or payable in any manner out of
Revenues in any manner other than in accordance with the provisions of this
Indenture, and shall not suffer or permit any default to occur under this
Indenture, but shall faithfully observe and perform all the covenants,
conditions and requirements hereof.

         Section 6.06. Arbitrage Covenants; Rebate Fund.

         (a)      The Authority covenants with all persons who hold or at any
time held Bonds that the Authority will not directly or indirectly use the
proceeds of any of the Bonds or any other funds of the Authority or permit the
use of the proceeds of any of the Bonds or any other funds of the Authority or
take or omit to take any other action which will cause any of the Bonds to be
"arbitrage bonds" or otherwise subject to federal income taxation by reason of
Sections 103 and 141 through 150 of the Code and any applicable regulations
promulgated thereunder. To that end the Authority covenants to comply with all
covenants set forth in the Tax Certificate, which is hereby incorporated herein
by reference as though fully set forth herein.

         (b)      The Trustee shall establish and maintain a fund separate from
any other fund established and maintained hereunder designated the "California
Pollution Control Financing Authority Pollution Control Refunding Revenue Bonds
(Laidlaw Environmental Services, Inc.) 1997 Series A Rebate Fund" (herein called
the "Rebate Fund"). Within the Rebate Fund, the Trustee shall maintain such
accounts as shall be directed by the Borrower as necessary in order for the
Authority and the Borrower to comply with the terms and requirements of the Tax
Certificate. Subject to the transfer provisions provided in paragraph (c) below,
all money at any time deposited in the Rebate Fund shall be held by the Trustee
in trust, to the extent required to satisfy the Rebate Requirement (as defined
in the Tax Certificate), for

                                       28
<PAGE>

payment to the United States Government, and neither the Borrower, the Authority
nor the Bondholders shall have any rights in or claim to such moneys. All
amounts deposited into or on deposit in the Rebate Fund shall be governed by
this Section 6.06, by Section 5.6 of the Agreement and by the Tax Certificate.
The Trustee shall conclusively be deemed to have complied with such provisions
if it follows the directions of the Borrower, including supplying all necessary
information requested by the Borrower and the Authority in the manner set forth
in the Tax Certificate, and shall not be required to take any actions thereunder
in the absence of written directions from the Borrower.

         (c)      Upon receipt of the Borrower's written instructions, the
Trustee shall remit part or all of the balances in the Rebate Fund to the United
States Government, as so directed. In addition, if the Borrower so directs, the
Trustee will deposit moneys into or transfer moneys out of the Rebate Fund from
or into such accounts or funds as directed by the Borrower's written directions.
Any funds remaining in the Rebate Fund after redemption and payment of all of
the Bonds and payment and satisfaction of any Rebate Requirement shall be
withdrawn and remitted to the Borrower upon its written request.

         (d)      Notwithstanding any provision of this Indenture, including in
particular Article X hereof, the obligation of the Borrower to pay the Rebate
Requirement to the United States Government and to comply with all other
requirements of this Section 6.06, Section 5.6 of the Agreement and the Tax
Certificate shall survive the defeasance or payment in full of the Bonds.

         Section 6.07. Other Liens. So long as any Bonds are Outstanding, the
Authority shall not create or suffer to be created any pledge, lien or charge of
any type whatsoever upon all or any part of the Revenues, other than the lien of
this Indenture.

         Section 6.08. Further Assurances. Whenever and so often as requested so
to do by the Trustee, the Authority shall promptly execute and deliver or cause
to be executed and delivered all such other and further instruments, documents
or assurances, and promptly do or cause to be done all such other and further
things, as may be necessary or reasonably required in order to further and more
fully vest in the Trustee and the Bondholders all of the rights, interests,
powers, benefits, privileges and advantages conferred or intended to be
conferred upon them by this Indenture and to perfect and maintain as perfected
such rights, interests, powers, benefits, privileges and advantages.

                                       29
<PAGE>

                                   ARTICLE VII

                                     DEFAULT

         Section 7.01. Events of Default; Acceleration; Waiver of Default. Each
of the following events shall constitute an "Event of Default" hereunder:

         (a)      Failure to make payment of any installment of interest upon
any Bond when such payment shall have become due and payable;

         (b)      Failure to make due and punctual payment of the principal of
any Bond when such payment shall have become due and payable, whether at the
stated maturity thereof, or upon proceedings for redemption thereof or upon the
maturity thereof by declaration;

         (c)      The occurrence of an "Event of Default" under the Agreement,
as specified in Section 6.1 thereof; or

         (d)      Default by the Authority in the performance or observance of
any other of the covenants, agreements or conditions on its part contained in
this Indenture or in the Bonds, and the continuance of such default for a period
of sixty (60) days after written notice thereof, specifying such default and
requiring the same to be remedied, shall have been given to the Authority and
the Borrower by the Trustee, or to the Authority, the Borrower and the Trustee
by the holders of not less than twenty-five percent (25%) in aggregate principal
amount of the Bonds at the time Outstanding;

         No default specified in (d) above shall constitute an Event of Default
unless the Authority and the Borrower shall have failed to correct such default
within the applicable 30-day period; provided, however, that if the default
shall be such that it can be corrected, but cannot be corrected within such
period, it shall not constitute an Event of Default if corrective action is
instituted by the Authority or the Borrower within the applicable period and
diligently pursued until the default is corrected. With regard to any alleged
default concerning which notice is given to the Borrower under the provisions of
this Section, the Authority hereby grants the Borrower full authority for the
account of the Authority to perform any covenant or obligation the
non-performance of which is alleged in said notice to constitute a default in
the name and stead of the Authority with full power to do any and all things and
acts to the same extent that the Authority could do and perform any such things
and acts and with power of substitution. Notwithstanding such grant, the
Borrower shall not have any obligation to cure any default of the Authority.

         Upon the occurrence and continuation of an Event of Default under
Section 7.01(a), (b), (c) or (d) hereof, the

                                       30
<PAGE>

Trustee may, and upon the written request of the holders of not less than
twenty-five percent (25%) in aggregate principal amount of Bonds then
Outstanding, shall, by notice in writing delivered to the Borrower, with copies
of such notice being sent to the Authority, declare the principal of all Bonds
then Outstanding and the interest accrued thereon immediately due and payable,
and such principal and interest shall thereupon become and be immediately due
and payable. Interest on the Bonds shall cease to accrue from and after the date
of declaration of any such acceleration. Notwithstanding the foregoing, the
Trustee shall not be required to take any action upon the occurrence and
continuation of an Event of Default under Section 7.01(c) or (d) above until a
Responsible Officer of the Trustee has actual knowledge of such Event of
Default. After any declaration of acceleration under this Section 7.01 the
Trustee shall immediately declare all indebtedness payable under Section 4.2(a)
of the Agreement with respect to the Bonds to be immediately due and payable in
accordance with Section 7.3 of the Agreement and may exercise and enforce such
rights as exist under the Agreement.

         The preceding paragraph, however, is subject to the condition that if,
at any time after the principal of the Bonds shall have been so declared due and
payable, and before any judgment or decree for the payment of the moneys due
shall have been obtained or entered as hereinafter provided, there shall have
been deposited with the Trustee a sum which, together with any other amounts
then held in the Bond Fund, is sufficient to pay all the principal of such Bonds
matured prior to such declaration and all matured installments of interest (if
any) upon all the Bonds, and the reasonable expenses (including reasonable
attorneys' fees) of the Trustee, and any and all other defaults actually known
to the Trustee (other than in the payment of principal of and interest on such
Bonds due and payable solely by reason of such declaration) shall have been made
good or cured to the satisfaction of the Trustee in its sole discretion or
provision deemed by the Trustee to be adequate shall have been made therefor,
then, and in every such case, the holders of at least a majority in aggregate
principal amount of the Bonds then Outstanding, by written notice to the
Authority and to the Trustee may, on behalf of the holders of all Bonds, rescind
and annul such declaration with respect to the Bonds and its consequences and
waive such default; provided that no such rescission and annulment shall extend
to or shall affect any subsequent default, or shall impair or exhaust any right
or power consequent thereon.

         Section 7.02. Institution of Legal Proceedings by Trustee. In addition,
if one or more of the Events of Default hereunder shall happen and be
continuing, the Trustee in its sole discretion may, and upon the written request
of the holders of a majority in aggregate principal amount of the Bonds then
Outstanding, and upon being indemnified to its satisfaction in its sole
discretion therefor (including with respect to any

                                       31
<PAGE>

expenses or liability the Trustee may incur) shall, proceed to protect or
enforce its rights or the rights of the holders of Bonds under the Act or under
this Indenture, by a suit in equity or action at law, either for the specific
performance of any covenant or agreement contained herein, or in aid of the
execution of any power herein granted, or by mandamus or other appropriate
proceeding for the enforcement of any other legal or equitable remedy as the
Trustee shall deem most effectual in support of any of its rights or duties
hereunder. If the Trustee reasonably determines that it may not receive payment
for its extraordinary services and expenses relating to the enforcement of its
rights or the rights of the holders of the Bonds under the Act or under the
Indenture, the Trustee shall have no duty to act if it gives written notice of
such decision to the Bondholders and the Bondholders subsequently fail to
provide the Trustee with reasonable indemnification.

         Section 7.03. Application of Moneys Collected by Trustee. Any moneys
collected by the Trustee and moneys in the Bond Fund on or after the occurrence
of an Event of Default shall be applied in the order following, at the date or
dates fixed by the Trustee and, in the case of distribution of such moneys on
account of principal or interest, upon presentation of the Bonds, and stamping
thereon the payment, if only partially paid, and upon surrender thereof, if
fully paid:

           First:  To the payment of costs and expenses of collection, just and
         reasonable compensation to the Trustee for its own services and for the
         services of counsel, agents and employees by it properly engaged and
         employed, and for advances made pursuant to the provisions of this
         Indenture with interest on all such advances at the rate of nine
         percent (9%) per annum.

           Second: In case the principal of none of the Outstanding Bonds shall
         have become due and remains unpaid, to the payment of interest in
         default on the Outstanding Bonds in the order of the maturity thereof,
         such payments to be made ratably and proportionately to the persons
         entitled thereto without discrimination or preference, except as
         specified in Section 6.02; provided, however, that no payment of
         interest shall be made with respect to any Bonds held by the Authority
         or the Borrower or actually known by the Trustee to be held by any
         affiliate of the Borrower, or any nominee of the Authority, the
         Borrower, any affiliate of the Borrower, until interest due on all
         Bonds not so registered shall have been paid.

           Third:  In case the principal of any of the Outstanding Bonds shall
         have become due by declaration or otherwise and remains unpaid, first
         to the payment of principal of all Outstanding Bonds then due and
         unpaid, then to the payment of interest in default in the order

                                       32

<PAGE>

         of maturity thereof; in every instance such payment to be made ratably
         to the persons entitled thereto without discrimination or preference,
         except as specified in Section 6.02; provided, however, that no payment
         of principal or interest shall be made with respect to any Bonds held
         by the Authority or the Borrower or known by the Trustee to be held by
         any affiliate of the Borrower or any nominee of the Authority, the
         Borrower or any affiliate of the Borrower, until all amounts due on all
         Bonds not so held have been paid.

         Section 7.04. Effect of Delay or Omission to Pursue Remedy. No delay or
omission of the Trustee or of any holder of Bonds to exercise any right or power
arising from any default shall impair any such right or power or shall be
construed to be a waiver of any such default or acquiescence therein, and every
power and remedy given by this Article VII to the Trustee or to the holders of
Bonds may be exercised from time to time and as often as shall be deemed
expedient. In case the Trustee shall have proceeded to enforce any right under
this Indenture, and such proceedings shall have been discontinued or abandoned
because of waiver or for any other reason, or shall have been determined
adversely to the Trustee, then and in every such case the Authority, the
Trustee, and the holders of the Bonds, severally and respectively, shall be
restored to their former positions and rights hereunder in respect to the trust
estate; and all remedies, rights and powers of the Authority, the Trustee and
the holders of the Bonds shall continue as though no such proceedings had been
taken.

         Section 7.05. Remedies Cumulative. No remedy herein conferred upon or
reserved to the Trustee or to any holder of the Bonds is intended to be
exclusive of any other remedy, but each and every such remedy shall be
cumulative and shall be in addition to every other remedy given hereunder or now
or hereafter existing at law or in equity.

         Section 7.06. Covenant to Pay Bonds in Event of Default. The Authority
covenants that, upon the happening of any Event of Default, the Authority will
pay to the Trustee upon demand, but only out of Revenues, for the benefit of the
holders of such Bonds, the whole amount then due and payable thereon (by
declaration or otherwise) for interest or for principal and all other sums which
may be due hereunder or secured hereby, including reasonable compensation to the
Trustee, its agents and counsel, and any expenses or liabilities incurred by the
Trustee hereunder. In case the Authority shall fail to pay the same forthwith
upon such demand, the Trustee, in its own name and as trustee of an express
trust, shall be entitled to institute proceedings at law or in equity in any
court of competent jurisdiction to recover judgment for the whole amount due and
unpaid, together with costs and reasonable attorneys' fees and expenses,
subject, however, to the condition that such judgment, if any, shall be limited
to, and payable solely out of, Revenues

                                       33

<PAGE>

as herein provided and not otherwise. The Trustee shall be entitled to recover
such judgment as aforesaid, either before or after or during the pendency of any
proceedings for the enforcement of this Indenture, and the right of the Trustee
to recover such judgment shall not be affected by the exercise of any other
right, power or remedy for the enforcement of the provisions of this Indenture.
If the Event of Default involves the bankruptcy of the Borrower, amounts payable
to or for the benefit of the Bondholders pursuant to the bankruptcy plan shall
be paid to the Trustee for application as provided in Section 7.03 of the
Indenture; and if payments are made directly to the Bondholders by the
bankruptcy trustee, those Bondholders shall be liable to the Trustee for
applying the funds in the manner provided in Section 7.03 hereof, including, but
not limited to, the payment of the Trustee's extraordinary fees and expenses.

         Section 7.07. Trustee Appointed Agent for Bondholders. The Trustee is
hereby appointed the agent and attorney of the holders of all Bonds Outstanding
hereunder for the purpose of filing any claims relating to the Bonds.

         Section 7.08. Power of Trustee to Control Proceedings. In the event
that the Trustee, upon the happening of an Event of Default, shall have taken
any action, by judicial proceedings or otherwise, pursuant to its duties
hereunder, whether upon its own discretion or upon the request of holders of the
Bonds, it shall have full power, in the exercise of its discretion for the best
interests of the holders of the Bonds, with respect to the continuance,
discontinuance, withdrawal, compromise, settlement or other disposal of such
action; provided, however, that the Trustee shall not, unless there no longer
continues an Event of Default hereunder, discontinue, withdraw, compromise or
settle, or otherwise dispose of any litigation pending at law or in equity, if
at the time there has been filed with it a written request signed by the holders
of at least a majority in principal amount of the Bonds Outstanding hereunder
opposing such discontinuance, withdrawal, compromise, settlement or other
disposal of such litigation.

         All rights of action under this Indenture or under any of the Bonds
secured hereby which are enforceable by the Trustee may be enforced by it
without the possession of any of the Bonds, or the production thereof at the
trial or other proceedings relative thereto, and any such suit, action or
proceeding instituted by the Trustee shall be brought in its name as Trustee of
an express trust for the equal and ratable benefit of the Bondholders, subject
to the provisions of this Indenture.

         Section 7.09. Limitation on Bondholders' Right to Sue. No holder of any
Bond issued hereunder shall have the right to institute any suit, action or
proceeding at law or in equity, for any remedy under or upon this Indenture,
unless (a) such holder shall have previously given to the Trustee written notice
of the occurrence of an Event of Default hereunder; (b) the holders of

                                       34

<PAGE>

at least a majority in aggregate principal amount of all the Bonds then
Outstanding shall have made written request upon the Trustee to exercise the
powers hereinbefore granted or to institute such action, suit or proceeding in
its own name; (c) said holders shall have tendered to the Trustee indemnity
satisfactory to it against the costs, expenses (including reasonable attorneys'
fees) and liabilities to be incurred in compliance with such request; and (d)
the Trustee shall have refused or omitted to comply with such request for a
period of thirty (30) days after such written request shall have been received
by, and said tender of indemnity shall have been made to, the Trustee.

         Such notification, request, tender of indemnity and refusal or omission
are hereby declared, in every case, to be conditions precedent to the exercise
by any holder of Bonds of any remedy hereunder; it being understood and intended
that no one or more holders of Bonds shall have any right in any manner whatever
by his or her or their action to enforce any right under this Indenture, except
in the manner herein provided, and that all proceedings at law or in equity to
enforce any provision of this Indenture shall be instituted, had and maintained
in the manner herein provided and for the equal benefit of all holders of the
Outstanding Bonds, subject to the provisions of this Indenture.

         The right of any holder of any Bond to receive payment of the principal
of and interest on such Bond out of Revenues, as herein and therein provided, on
and after the respective due dates expressed in such Bond, or to institute suit
for the enforcement of any such payment on or after such respective dates, shall
not be impaired or affected without the consent of such holder, notwithstanding
the foregoing provisions of this Section or Section 7.08 or any other provision
of this Indenture.

         Section 7.10. Limitation of Liability to Revenues. Notwithstanding
anything in this Indenture contained, the Authority shall not be required to
advance any moneys derived from the proceeds of taxes collected by the Authority
or by any governmental body or political subdivision of the State or from any
source of income of any governmental body or political subdivision of the State
or the Authority other than the Revenues, for any of the purposes in this
Indenture mentioned, whether for the payment of the principal of or interest on
the Bonds or for any other purpose of this Indenture. The Bonds are not general
obligations of the Authority, and are payable from and secured by the Revenues
only.

                                       35
<PAGE>

                                  ARTICLE VIII

                          THE TRUSTEE AND THE REGISTRAR

         Section 8.01. Duties, Immunities and Liabilities of Trustee and
Registrar. The Trustee and the Registrar shall, prior to an Event of Default
hereunder, and after the curing of all Events of Default hereunder which may
have occurred, perform such duties and only such duties as are specifically set
forth in this Indenture. The Trustee shall, during the existence of any Event of
Default hereunder (which has not been cured), 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 prudent persons would exercise or use under the
circumstances in the conduct of their own affairs.

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

         (a)      Prior to the occurrence of any Event of Default hereunder and
after the curing of all Events of Default which may have occurred, the duties
and obligations of the Trustee and the Registrar, as the case may be, shall be
determined solely by the express provisions of this Indenture; the Trustee or
the Registrar, as the case may be, shall not be liable except for the
performance of such duties and obligations as are specifically set forth in this
Indenture; and no covenants or obligations shall be implied into this Indenture
which are adverse to the Trustee or the Registrar, as the case may be; and

         (b)      At all times, regardless of whether or not any Event of
Default shall exist,

           (1)    the Trustee and the Registrar shall not be liable for any
         error of judgment made in good faith by a Responsible Officer or
         Officers of the Trustee or the Registrar unless it shall be proved that
         the Trustee or the Registrar, as the case may be, was negligent in
         ascertaining the pertinent facts; and

           (2)    neither the Trustee nor the Registrar shall be personally
         liable with respect to any action taken, permitted or omitted by it in
         good faith in accordance with the direction of the holders of not less
         than a majority, or such other percentage as may be required hereunder,
         in aggregate principal amount of the Bonds Outstanding relating to the
         time, method and place of conducting any proceeding for any remedy
         available to the Trustee or the Registrar, or exercising any trust or
         power conferred upon the Trustee or the Registrar under this Indenture;
         and

                                       36

<PAGE>

           (3)    in the absence of bad faith on the part of the Trustee or the
         Registrar, as the case may be, the Trustee and the Registrar may
         conclusively rely, as to the truth of the statements and the
         correctness of the opinions expressed therein, upon any certificate or
         opinion furnished to the Trustee or the Registrar, as the case may be,
         conforming to the requirements of this Indenture; but in the case of
         any such certificate or opinion which by any provision hereof is
         specifically required to be furnished to the Trustee or the Registrar,
         as the case may be, the Trustee or the Registrar, as the case may be,
         shall be under a duty to examine the same to determine whether or not
         it conforms to the requirements of this Indenture.

         (c)      The Trustee may execute any of the trusts or powers hereof and
 perform the duties required of it hereunder by or through attorneys, agents or
 receivers, and shall be entitled to advice of counsel concerning all matters of
 trust and concerning its duties hereunder and the Trustee shall not be
 responsible for any misconduct or negligence on the part of any attorney or
 agent appointed with due care by it hereunder.

         None of the provisions contained in this Indenture shall require the
Trustee or the Registrar to expend or risk its own funds or otherwise incur
individual financial liability in the performance of any of its duties or in the
exercise of any of its rights or powers. The permissive right of the Trustee to
perform acts enumerated in this Indenture or the Agreement shall not be
construed as a duty or obligation hereunder.

         Section 8.02. Right of Trustee and Registrar to Rely upon the
Agreement, Etc. Except as otherwise provided in Section 8.01:

         (a)      The Trustee and the Registrar may rely and shall be protected
in acting upon any resolution, certificate, statement, instrument, opinion,
report, notice, request, consent, order, Bond, direction, demand, election 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 notice, request, direction, election, order or demand of
the Authority mentioned herein shall be deemed to be sufficiently evidenced by
an instrument signed in the name of the Authority by an Authorized Authority
Representative, and any resolution of the Authority shall be evidenced to the
Trustee or the Registrar by a Certified Resolution;

         (c)      Each of the Trustee and the Registrar may consult with counsel
of its selection (who may include its own counsel or counsel for the Authority
or Bond Counsel) and the opinion of such counsel shall be full and complete
authorization and protection in respect of any action taken or suffered by it

                                       37
<PAGE>

  hereunder in good faith and in accordance with the opinion of such counsel;
  and

         (d)      Whenever in the administration of the trusts of this
  Indenture the Trustee or the Registrar shall deem it necessary or desirable
  that a matter be proved or established prior to taking or suffering any action
  hereunder, such matter (unless other evidence in respect thereof be herein
  specifically prescribed) may, in the absence of negligence or bad faith on the
  part of the Trustee or the Registrar, as the case may be, be deemed to be
  conclusively proved and established by a Certificate of the Authority; and
  such Certificate of the Authority shall, in the absence of negligence or bad
  faith on the part of the Trustee or the Registrar, as the case may be, be full
  warrant to the Trustee or the Registrar, as the case may be, for any action
  taken or suffered by it under the provisions of this Indenture upon the faith
  thereof.

         Section 8.03. Trustee and Registrar Not Responsible for Recitals. The
recitals contained herein and in the Bonds shall be taken as the statements of
the Authority, and the Trustee and the Registrar assume no responsibility for
the correctness of the same except (with respect to the Registrar) for the
Certificate of Authentication thereon. The Trustee and the Registrar make no
representations as to the validity or sufficiency of this Indenture or of the
Bonds. The Trustee and the Registrar shall not be accountable for the use or
application by the Authority of any of the Bonds authenticated or delivered
hereunder or of the proceeds of such Bonds except to the extent specifically
provided in this Indenture.

         Section 8.04. Right of Trustee and Registrar to Acquire Bonds. The
Trustee, the Registrar and their officers and directors may acquire and hold, or
become the pledgee of, Bonds and otherwise deal with the Authority in the manner
and to the same extent and with like effect as though it were not Trustee or
Registrar, as the case may be, hereunder.

         Section 8.05. Moneys Received by Trustee and Registrar to Be Held in
Trust. Subject to the provisions of Section 10.03, all moneys received by the
Trustee and the Registrar shall, until used or applied as herein provided, be
held in trust for the purposes for which they were received, but need not be
segregated from other funds except to the extent required by law or as otherwise
provided herein. Except to the extent provided otherwise herein, any interest
allowed on any such moneys shall be deposited in the fund to which such moneys
are credited.

         Section 8.06. Compensation and Indemnification of Trustee and
Registrar. The Trustee and the Registrar shall be entitled to reasonable
compensation for all services rendered by them in the execution of the trusts
created and in the exercise and performance of any of the powers and duties
hereunder of the Trustee or the Registrar, as the case may be, which
compensation

                                       38
<PAGE>

shall not be limited by any provision of law in regard to the compensation of a
trustee of an express trust, and the Agreement will require the Borrower to pay
or reimburse the Trustee or the Registrar, as the case may be, upon its request
for all reasonable expenses, disbursements and advances incurred or made by the
Trustee or the Registrar, as the case may be, in accordance with any of the
provisions of this Indenture (including the reasonable compensation and the
expenses and disbursements of its counsel and of all persons not regularly in
its employ) except any such expense, disbursement or advance as may arise from
its negligence or bad faith. If any property, other than cash, shall at any time
be held by the Trustee or the Registrar, as the case may be, subject to this
Indenture, or any supplemental indenture, as security for the Bonds, the Trustee
or the Registrar, as the case may be, if and to the extent authorized by a
receivership, bankruptcy or other court of competent jurisdiction or by the
instrument subjecting such property to the provisions of this Indenture as such
security for the Bonds, shall be entitled (but not required) to make advances
for the purpose of preserving such property or of discharging tax liens or other
prior liens or encumbrances thereon. The Agreement will also require the
Borrower to provide certain indemnification to the Trustee and the Registrar.
Notwithstanding the foregoing, prior to seeking indemnity the Trustee shall make
timely payments of principal of and interest on the Bonds with moneys on deposit
in the Bond Fund as provided herein, and shall accelerate the payment of
principal on the Bonds when required by this Indenture without seeking
indemnification from the Borrower or any Bondholder. Upon the occurrence and
continuance of an Event of Default hereunder, and subject to Section 7.03
hereof, the Trustee shall have a lien prior to the Bonds as to all property and
funds held by it (other than the Rebate Fund) for any amount owing to it or any
predecessor Trustee pursuant to this Section 8.06 or the Agreement and the
rights of the Trustee to compensation for its services and to payment or
reimbursement for its costs, expenses, or advances shall have priority over the
Bonds in respect of all property or funds held or collected by the Trustee as
such and other funds held in trust by the Trustee for the benefit of the holders
of particular Bonds.

         When the Trustee incurs expenses or renders services in connection with
an Event of Default specified in Section 6.1(c) of the Agreement and Section
7.01 hereof, such expenses (including the reasonable charges and expenses of its
counsel and agents) and the compensation for such services are intended to
constitute expenses of administration under any applicable federal or state
bankruptcy, insolvency or other similar law. The Trustee shall be entitled to
all reasonable fees and expenses incurred in enforcing the Bondholders' rights
in any bankruptcy action, and the intention that the fees and expenses incurred
by the Trustee in enforcing the rights of the Bondholders be treated as expenses
of administration under any applicable federal or state bankruptcy, insolvency
or other similar law shall not be

                                       39
<PAGE>

deemed to limit the amount payable to the Trustee. The provisions of this
Section 8.06 shall survive the termination of this Indenture and the resignation
or removal of the Trustee or the Registrar.

         Section 8.07. Qualifications of Trustee and Registrar. There shall at
all times be a trustee and a registrar hereunder which shall be corporations or
banking associations organized and doing business under the laws of the United
States or of a state thereof, authorized under such laws to exercise corporate
trust powers, having a combined capital and surplus of at least fifty million
dollars ($50,000,000), subject to supervision or examination by federal or state
authority. If such corporations or banking associations publish reports of
condition at least annually, pursuant to law or to the requirements of any
supervising or examining authority above referred to, then for the purposes of
this Section the combined capital and surplus of such corporations or banking
associations shall be deemed to be their combined capital and surplus as set
forth in their most recent reports of conditions so published. In case at any
time the Trustee or the Registrar shall cease to be eligible in accordance with
the provisions of this Section, the Trustee or the Registrar, as the case may
be, shall resign immediately in the manner and with the effect specified in
Section 8.08.

         Section 8.08. Resignation and Removal of Trustee or Registrar and
Appointment of Successor Trustee or Registrar.

         (a)      The Trustee or the Registrar may at any time resign by giving
written notice to the Authority and the Borrower and by giving to the
Bondholders notice either by publication of such resignation, which notice shall
be published at least once in a Qualified Newspaper, or by giving Notice by Mail
to such Bondholders. Upon receiving such notice of resignation, the Authority,
with the advice and consent of the Borrower, shall promptly appoint a successor
trustee or registrar, as the case may be, by an instrument in writing. If no
successor trustee or registrar, as the case may be, shall have been so appointed
and have accepted appointment within thirty (30) days after the giving of such
notice of resignation by the Trustee or the Registrar, as the case may be, the
resigning trustee or registrar, as the case may be, may petition any court of
competent jurisdiction for the appointment of a successor trustee or registrar,
as the case may be, or any Bondholder who has been a bona fide holder of a Bond
for at least six (6) months may, on behalf of himself and others similarly
situated, petition any such court for the appointment of a successor trustee or
registrar, as the case may be. Such court may thereupon, after such notice, if
any, as it may deem proper and may prescribe, appoint a successor trustee or
registrar, as the case may be.

         (b)      In case at any time either of the following shall occur:

                                       40
<PAGE>

                  (1) the Trustee or the Registrar shall cease to be eligible in
         accordance with the provisions of Section 8.07 and shall fail to resign
         after written request therefor by the Authority or by any Bondholder
         who has been a bona fide holder of a Bond for at least six (6) months,
         or

                  (2) the Trustee or the Registrar shall become incapable of
         acting, or shall be adjudged a bankrupt or insolvent, or a receiver of
         the Trustee or Registrar or of its property shall be appointed, or any
         public officer shall take charge or control of the Trustee or Registrar
         or of its property or affairs for the purpose of rehabilitation,
         conservation or liquidation,

then, in any such case, the Authority may remove the Trustee or the Registrar,
as the case may be, and, with the advice and consent of the Borrower, appoint a
successor trustee or registrar, as the case may be, by an instrument in writing,
or any such Bondholder may, on behalf of itself and all others similarly
situated, petition any court of competent jurisdiction for the removal of the
Trustee or the Registrar, as the case may be, and the appointment of a successor
trustee or registrar, as the case may be. Such court may thereupon, after such
notice, if any, as it may deem proper and may prescribe, remove the Trustee or
the Registrar, as the case may be, and appoint a successor trustee or registrar,
as the case may be. Upon any removal of the Trustee, any outstanding fees and
expenses of such former Trustee shall be paid in accordance with Section 8.06
hereof.

         (c)      The Authority, in the absence of an Event of Default, or the
holders of a majority in aggregate principal amount of the Bonds at the time
Outstanding may at any time remove the Trustee or the Registrar, as the case may
be, and appoint a successor trustee or registrar, as the case may be, by an
instrument or concurrent instruments in writing signed by the Authority or such
Bondholders, as the case may be.

         (d)      Any resignation or removal of the Trustee or the Registrar, as
the case may be, and appointment of a successor trustee or registrar, as the
case may be, pursuant to any of the provisions of this Section shall become
effective only upon acceptance of appointment by the successor trustee or
registrar, as the case may be, as provided in Section 8.09.

         Section 8.09. Acceptance of Trust by Successor Trustee. Any successor
trustee appointed as provided in Section 8.08 shall execute, acknowledge and
deliver to the Authority, the Borrower and to its predecessor trustee an
instrument accepting such appointment hereunder, and thereupon the resignation
or removal of the predecessor trustee shall become effective and such successor
trustee, without any further act, deed or conveyance, shall become vested with
all the rights, powers, trusts, duties and obligations of its predecessor in the
trusts hereunder, with

                                       41

<PAGE>

like effect as if originally named as Trustee herein; but, nevertheless, on the
Written Request of the Authority or the request of the successor trustee, the
trustee ceasing to act shall execute and deliver an instrument transferring to
such successor trustee, upon the trusts herein expressed, all the rights, powers
and trusts of the trustee so ceasing to act. Upon request of any such successor
trustee, the Authority shall execute any and all instruments in writing
necessary or desirable for more fully and certainly vesting in and confirming to
such successor trustee all such rights, powers and duties. Any trustee ceasing
to act shall, nevertheless, retain a lien upon all property or funds held or
collected by such trustee to secure the amounts due it as compensation,
reimbursement, expenses and indemnity afforded to it by Section 8.06.

         No successor trustee shall accept appointment as provided in this
Section 8.09 unless at the time of such acceptance such successor trustee shall
be eligible under the provisions of Section 8.07.

         Upon acceptance of appointment by a successor trustee as provided in
this Section, the Authority or such successor trustee shall give the
Bondholders, notice of the succession of such trustee to the trusts hereunder in
the manner prescribed in Section 8.08 for the giving of notice of resignation of
the Trustee.

         Section 8.10. Merger or Consolidation of Trustee or Registrar. Any
corporation or banking association into which the Trustee may be merged or with
which it may be consolidated, or any corporation or banking association
resulting from any merger or consolidation to which the Trustee or the Registrar
shall be a party, or any corporation or banking association succeeding to all or
substantially all of the corporate trust business of the Trustee or the
Registrar, shall be the successor of the Trustee or the Registrar hereunder
without the execution or filing of any paper or any further act on the part of
any of the parties hereto, anything herein to the contrary notwithstanding,
provided that such successor trustee or registrar shall be eligible under the
provisions of Section 8.07.

         Section 8.11. Accounting Records and Reports; Financing Statements. The
Trustee and the Registrar shall keep proper books of record and account in
accordance with trust accounting standards in which complete and correct entries
shall be made of all transactions relating to the receipt, investment,
disbursement, allocation and application of the Revenues and the proceeds of the
Bonds received by the Trustee or the Registrar. Such records shall specify the
account or fund to which each investment (or portion thereof) held by the
Trustee is to be allocated and shall set forth, in the case of each Investment
Security, (a) its purchase price, (b) its value at maturity or its sale price,
as the case may be, (c) the amounts and dates of any payments to be made with
respect thereto and (d) such

                                       42
<PAGE>

documentation and evidence as is required to be obtained by the Borrower to
establish that the requirements of Article V of the Tax Certificate have been
met. Such records shall be open to inspection by the Authority, the Borrower and
by any Bondholder at any reasonable time during regular business hours on
reasonable notice. The Trustee shall furnish to the Authority and the Borrower
monthly statements of all investments made by the Trustee and all funds and
accounts held by the Trustee.

         The Trustee shall furnish to any Bondholder who may make written
request therefor a copy of the most recent audited financial statements of the
Borrower that are in the possession of the Trustee. The Trustee shall have no
responsibility or liability with respect to the Borrower's failure to provide
such statements, and the Trustee shall not be required to compel the Borrower to
provide any such statements.

         The Trustee shall not be responsible for the preparation or filing of
any UCC financing statements or continuation statements under this Indenture.

         Section 8.12. Registrar. The Authority, at the request and direction of
the Borrower, shall appoint a registrar for the Bonds. The Registrar shall be a
bank, trust company or national banking association which meets the
qualifications of Section 8.07 hereof, willing and able to accept the office on
reasonable and customary terms and authorized by law to perform all the duties
imposed upon it hereby. The Registrar shall signify its acceptance of the duties
and obligations imposed upon it hereby by executing and delivering to the
Authority and the Trustee a written acceptance thereof. The Registrar initially
appointed hereunder is the Trustee.

         Section 8.13. Tax Certificate. The Trustee covenants and agrees
that it will comply with all written instructions of the Borrower given in
accordance with the Tax Certificate and will take any and all action as may be
necessary in accordance with such written instructions. The Trustee acknowledges
receipt of the Tax Certificate and acknowledges that the provisions of the Tax
Certificate are incorporated herein by reference as provided in Section 6.06
hereof. The Trustee shall not be accountable for the use by the Borrower of the
proceeds of the Bonds.

         Section 8.14. Notices to the Authority. The Trustee shall provide the
Authority with the following:

         (a)      On or before January 15 of each year during which any of the
Bonds are Outstanding, or upon any significant change that occurs which would
adversely impact the Trustee's ability to perform its duties under the
Indenture, a written disclosure of any such change, or if applicable, of any
conflicts that the Trustee may have as a result of other business dealings
between the Trustee (or any affiliate thereof) and the Borrower.

                                       43

<PAGE>

If there are no such instances of a significant change, or of a conflict
existing, then a statement to that effect shall be provided on such date;

         (b)      If there is a failure to pay any amount of principal of or
interest on the Bonds when due; or if there is a failure of the Borrower to
provide any notice, certification or report specified in Section 5.9 of the
Agreement; or if there is an occurrence of an Event of Default hereunder, of
which the Trustee has knowledge, the Trustee shall provide written notice to the
Authority within five (5) Business Days of receiving actual notice of such
occurrence and such notice shall include a statement setting forth the steps, if
any, the Trustee is taking to remedy such failure or Event of Default, as
applicable; and

         (c)      As of June 30 and December 31 of each year (beginning December
31, 1997), a Trustee's report in the form of Exhibit A attached hereto. This
report shall be received no later than January 15 or July 15 next following each
such June 30 or December 31, as the case may be.

         Section 8.15. Appointment of Co-Trustee. In the event the Trustee deems
that by reason of any present or future law of any jurisdiction it may not
exercise any of the powers, rights or remedies herein granted to the Trustee or
hold title to the properties, in trust, as herein granted, or take any other
action which may be desirable or necessary in connection therewith, it may be
necessary that the Trustee appoint an additional institution as a separate
trustee or co-trustee. In the absence of an Event of Default under this
Indenture, the appointment of any such separate trustee or co-trustee shall be
subject to the approval of the Authority and the Borrower. The following
provisions of this Section are adapted to these ends.

         (a)      In the event that the Trustee appoints an additional
institution as a separate trustee or co-trustee, each and every remedy, power,
right, claim, demand, cause of action, immunity, estate, interest or lien
expressed or intended by this Indenture to be exercised by or vested in or
conveyed to the Trustee with respect thereto shall be exercisable by and vest in
such separate trustee or co-trustee but only to the extent necessary to enable
such separate trustee or co-trustee to exercise such powers, rights and
remedies, and every covenant and obligation necessary to the exercise thereof by
such separate trustee or co-trustee shall run to and be enforceable by either of
them. Such co-trustee may be removed by the Trustee at any time, with or without
cause.

         (b)      Should any instrument in writing from the Authority be
required by the separate trustee or co-trustee so appointed by the Trustee for
more fully and certainly vesting in and confirming to it such properties,
rights, powers, trusts, duties and obligations, any and all such instruments in
writing shall, on request, be executed, acknowledged and delivered by the

                                       44

<PAGE>

Authority. In case any separate trustee or co-trustee, or a successor to either,
shall become incapable of acting, resign or be removed, all the estates,
properties, rights, powers, trusts, duties and obligations of such separate
trustee or co-trustee, so far as permitted by law, shall vest in and be
exercised by the Trustee until the appointment of a successor to such separate
trustee or co-trustee.

                                   ARTICLE IX

                      MODIFICATION OF INDENTURE, AGREEMENT

         Section 9.01. Modification without Consent of Bondholders. The
Authority and the Trustee, without the consent of or notice to any Bondholders
from time to time and at any time, and subject to the conditions and
restrictions contained in this Indenture, may enter into an indenture or
indentures supplemental hereto, which indenture or indentures thereafter shall
form a part hereof; and the Trustee, without the consent of or notice to any
Bondholders from time to time and at any time, may consent to any Amendment to
the Agreement; in each case for any one or more of the following purposes:

         (a)   to add to the covenants and agreements of the Authority
  contained in this Indenture, or of the Borrower contained in the Agreement,
  other covenants and agreements thereafter to be observed, or to assign or
  pledge additional security for any of the Bonds, or to surrender any right or
  power herein or therein reserved to or conferred upon the Authority or the
  Borrower; provided, that no such covenant, agreement, assignment, pledge or
  surrender shall materially adversely affect the interests of the holders of
  the Bonds;

         (b)   to make such provisions for the purpose of curing any
  ambiguity, inconsistency or omission, or of curing, correcting or
  supplementing any defective provision contained in this Indenture or the
  Agreement, or in regard to matters or questions arising under this Indenture
  or the Agreement, as the Authority may deem necessary or desirable and not
  inconsistent with this Indenture and which shall not materially adversely
  affect the interests of the holders of the Bonds;

         (c)   to modify, amend or supplement this Indenture or any
  indenture supplemental hereto in such manner as to permit the qualification
  hereof or thereof under the Trust Indenture Act of 1939 or any similar federal
  statute hereafter in effect, and, if they so determine, to add to this
  Indenture or any indenture supplemental hereto such other terms, conditions
  and provisions as may be permitted by said Trust Indenture Act of 1939 or
  similar federal statute, and which shall not adversely affect the interests of
  the holders of the Bonds;

                                       45
<PAGE>

         (d)   to provide for any additional procedures, covenants or agreements
  necessary to maintain the Tax-Exempt status of interest on the Bonds; provided
  that such amendment or supplement shall not materially adversely affect the
  interests of the holders of the Bonds;

         (e)   to modify or eliminate the book-entry registration system for any
  of the Bonds;

         (f)   to provide for the procedures required to permit any Bondholder
  to separate the right to receive interest on the Bonds from the right to
  receive principal thereof and to sell or dispose of such rights, as
  contemplated by Section 1286 of the Code;

         (g)   to provide for the appointment of a co-trustee or the succession
  of a new Trustee, Registrar or Paying Agent;

         (h)   to change Exhibit A to the Agreement in accordance with the
  provisions thereof and of the Tax Certificate;

         (i)   to comply with requirements of any Rating Agency in order to
  obtain or maintain a rating on any Bonds; or

         (j)   in connection with any other change which, in the judgment of
  the Trustee (which may be based upon an Opinion of Counsel), will not
  adversely affect the security for the Bonds or the Tax-Exempt status of
  interest thereon or otherwise materially adversely affect the holders of the
  Bonds.

         Notwithstanding the foregoing provisions of this Section 9.01, the
Trustee 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, in which case the Trustee may in its discretion, but
shall not be obligated to, enter into such supplemental indenture, and the
Trustee shall not enter into any supplemental indenture or consent to any
Amendment without first obtaining the written consent of the Borrower. The
Trustee will give notice of the provisions of any supplemental indenture
authorized by the provisions of this Section 9.01 to the applicable Rating
Agencies. Any supplemental indenture or Amendment permitted pursuant to this
Section 9.01 may be approved by an Authorized Authority Representative and need
not be approved by resolution or other action of the Board of Directors of the
Authority.

         Section 9.02. Modification with Consent of Bondholders. With the
consent of the holders of not less than sixty-six and two-thirds percent
(662/3%) in aggregate principal amount of the Bonds at the time Outstanding,
evidenced as provided in Section 11.06, if any, (i) the Authority and the
Trustee may from time to time and at any time enter into an indenture or
indentures supplemental hereto for the purpose of adding any

                                       46
<PAGE>

provisions to or changing in any manner or eliminating any of the provisions of
this Indenture or of any supplemental indenture; or (ii) the Trustee may consent
to any Amendment to the Agreement and any other matters for which its consent is
required pursuant to Section 6.04 hereof; provided, however, that no such
supplement or Amendment will have the effect of extending the time for payment
or reducing any amount due and payable by the Borrower pursuant to the Agreement
without the consent of all the holders of the Bonds; and that no such
supplemental indenture shall (1) extend the fixed maturity of any Bond or reduce
the rate of interest thereon or extend the time of payment of interest, or
reduce the amount of the principal thereof, without the consent of the holder of
each Bond so affected, or (2) reduce the aforesaid percentage of holders of
Bonds whose consent is required for the execution of such supplemental
indentures, or permit the creation of any lien on the Revenues prior to or on a
parity with the lien of this Indenture, except as permitted herein, or permit
the creation of any preference of any Bondholder over any other Bondholder,
except as permitted herein, or deprive the holders of the Bonds of the lien
created by this Indenture upon the Revenues, without the consent of the holders
of all the Bonds then Outstanding. Nothing in this paragraph shall be construed
as making necessary the approval of any Bondholder of any supplemental indenture
or Amendment permitted by the provisions of Section 9.01.

         Upon receipt by the Trustee of a Certified Resolution authorizing the
execution of any such supplemental indenture or Amendment, and upon the filing
with the Trustee of evidence of the consent of the Bondholders, if any, as
aforesaid, the Trustee shall join with the Authority in the execution of such
supplemental indenture or shall consent to such Amendment; provided, however,
that (i) the Trustee 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, in which case the Trustee may in its sole
discretion, but shall not be obligated to, enter into such supplemental
indenture; and (ii) the Trustee shall not enter into such supplemental indenture
or Amendment without first obtaining the Borrower's written consent thereto.

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

         Promptly after the execution by the parties thereto of any supplemental
indenture or Amendment as provided in this Section, the Trustee shall mail a
notice (prepared by the Borrower) setting forth in general terms the substance
of such supplemental indenture or such Amendment to each Bondholder at the
address contained in the bond register maintained by the Registrar. Any failure
of the Trustee to give such notice, or any defect therein, shall not, however,
in any way impair or

                                       47
<PAGE>

affect the validity of any such supplemental indenture or such Amendment.

         Section 9.03.  Effect of Supplemental Indenture or Amendment. Upon the
execution of any supplemental indenture or any Amendment to the Agreement
pursuant to the provisions of this Article IX, this Indenture or the Agreement,
as the case may be, shall be and be deemed to be modified and amended in
accordance therewith, and the respective rights, duties and obligations under
this Indenture and the Agreement of the Authority, the Trustee, the Borrower and
all holders of Outstanding Bonds shall thereafter be determined, exercised and
enforced hereunder and under the Agreement subject in all respects to such
supplemental indentures and Amendments, and all the terms and conditions of any
such supplemental indenture or Amendment shall be part of the terms and
conditions of this Indenture or the Agreement, as the case may be, for any and
all purposes.

         Section 9.04.  Required and Permitted Opinions of Counsel. Subject to
the provisions of Section 8.01 hereof, the Trustee is entitled to receive an
Opinion of Counsel and rely on such Opinion of Counsel as conclusive evidence
that any supplemental indenture or Amendment executed pursuant to the provisions
of this Article IX complies with the requirements of this Article IX, that the
appropriate consents have been obtained and that such supplemental indenture or
Amendment has been duly authorized by the Authority.

         Section 9.05.  Notation of Modification on Bonds; Preparation of New
Bonds. Bonds authenticated and delivered after the execution of any supplemental
indenture pursuant to the provisions of this Article IX may bear a notation, at
the written request of the Authority, as to any matter provided for in such
supplemental indenture, and if such supplemental indenture shall so provide, new
Bonds, so modified as to conform, in the opinion of the Trustee and the
Authority, to any modification of this Indenture contained in any such
supplemental indenture, may be prepared by the Authority, authenticated by the
Registrar and delivered without cost to the holders of the Bonds then
Outstanding, upon surrender for cancellation of such Bonds in equal aggregate
principal amounts.

                                    ARTICLE X

                                   DEFEASANCE

         Section 10.01. Discharge of Indenture. If the entire indebtedness on
all Bonds Outstanding shall be paid and discharged in any one or more of the
following ways:

         (a)        by the payment of the principal of, and interest on all
  Bonds Outstanding, as and when the same become due and payable; or

                                       48

<PAGE>

         (b)        by the delivery to the Registrar, for cancellation by it, of
  all Bonds Outstanding;

and if all other sums payable hereunder by the Authority shall be paid and
discharged, then thereupon this Indenture shall cease, terminate and become null
and void except only as provided in Section 10.02 hereof, and thereupon the
Trustee shall, upon Written Request of the Authority, and upon receipt by the
Trustee of a Certificate of the Authority and an Opinion of Counsel, each
stating that in the opinion of the signers all conditions precedent to the
satisfaction and discharge of this Indenture have been complied with, forthwith
execute proper instruments acknowledging satisfaction of and discharging this
Indenture. The satisfaction and discharge of this Indenture shall be without
prejudice to the rights of the Trustee to charge and be reimbursed by the
Borrower for any expenditures which it may thereafter incur in connection
herewith.

         Any Bond or Authorized Denomination thereof shall be deemed to be paid
within the meaning of this Indenture when (a) payment of the principal of such
Bond or Authorized Denomination thereof, plus interest thereon to the due date
thereof (whether such due date is by reason of maturity or upon redemption as
provided herein) either (i) shall have been made or caused to be made in
accordance with the terms thereof, or (ii) shall have been provided for by
irrevocably depositing with the Trustee in trust and irrevocably setting aside
exclusively for such payment (1) moneys sufficient to make such payment and/or
(2) nonprepayable, noncallable Government Obligations maturing as to principal
and interest in such amount and at such time as will insure the availability of
sufficient moneys to make such payment, and (b) all necessary and proper fees,
compensation and expenses of the Trustee pertaining to any such deposit shall
have been paid or the payment thereof provided for to the satisfaction of the
Trustee. At such time as a Bond or Authorized Denomination thereof shall be
deemed to be paid hereunder, as aforesaid, such Bond or Authorized Denomination
thereof shall no longer be secured by or entitled to the benefits of this
Indenture, except for the purposes of any such payment from such moneys and/or
Government Obligations. The Trustee shall not be responsible for verifying the
sufficiency of funds provided to effect the defeasance of Bonds pursuant to this
Article X.

         The Authority and the Borrower may at any time surrender to the
Registrar for cancellation by it any Bonds previously authenticated and
delivered which the Authority or the Borrower lawfully may have acquired in any
manner whatsoever, and such Bonds, upon such surrender and cancellation, shall
be deemed to be paid and retired.

         Section 10.02. Discharge of Liability on Bonds. Upon the deposit with
the Trustee, in trust, at or before maturity, of money or securities in the
necessary amount (as provided in

                                       49
<PAGE>

Section 10.04) to pay or redeem Outstanding Bonds, whether upon or prior to
their maturity or the redemption date of such Bonds, (provided that, if such
Bonds are to be redeemed prior to the maturity thereof, notice of such
redemption shall have been given as in Article IV provided or provision
satisfactory to the Trustee shall have been made for giving such notice), all
liability of the Authority and the Borrower in respect of such Bonds shall
cease, terminate and be completely discharged, except that the Authority and the
Borrower shall remain liable for such payment but only from, and the Bondholders
shall thereafter be entitled only to payment (without interest accrued thereon
after such redemption date or maturity date) out of, the money deposited with
the Trustee as aforesaid for their payment, subject, however, to the provisions
of Sections 6.06 and 10.03.

         Section 10.03. Payment of Bonds after Discharge of Indenture.
Notwithstanding any provisions of this Indenture, and subject to applicable laws
of the State, any moneys deposited with the Trustee or any Paying Agent, in
trust for the payment of the principal of, or interest on, any Bonds remaining
unclaimed for two (2) years after the principal of any or all of the Outstanding
Bonds has become due and payable (whether at maturity or upon call for
redemption or by declaration as provided in this Indenture), shall then be
repaid to the Borrower upon its written request, and the holders of such Bonds
shall thereafter be entitled to look only to the Borrower for payment thereof,
and all liability of the Trustee or any Paying Agent with respect to such moneys
shall thereupon cease; provided, however, that before the repayment of such
moneys to the Borrower as aforesaid, the Trustee or Paying Agent, as the case
may be, shall (at the request and cost of the Borrower) first publish at least
once in a Qualified Newspaper a notice, in such form as may be deemed
appropriate by the Borrower and the Trustee, in respect of the Bonds so payable
and not presented and in respect of the provisions relating to the repayment to
the Borrower of the moneys held for the payment thereof. In the event of the
repayment of any such moneys to the Borrower as aforesaid, the holders of the
Bonds in respect of which such moneys were deposited shall thereafter be deemed
to be unsecured creditors of the Borrower for amounts equivalent to the
respective amounts deposited for the payment of such Bonds and so repaid to the
Borrower (without interest thereon).

         Section 10.04. Deposit of Money or Securities with Trustee. Whenever in
this Indenture it is provided or permitted that there be deposited with or held
in trust by the Trustee money or securities in the necessary amount to pay or
redeem any Bonds, the money or securities so to be deposited or held may include
money or securities held by the Trustee in the funds and accounts established
pursuant to this Indenture and shall be:

         (a)        Available amounts constituting lawful money of the United
  States of America in an amount equal to the principal amount of such Bonds and
  all unpaid interest thereon to

                                       50
<PAGE>

  maturity, except that, in the case of Bonds which are to be redeemed prior to
  maturity and in respect of which notice of such redemption shall have been
  given as provided in Article IV or provision satisfactory to the Trustee
  shall have been made for the giving of such notice, the amount to be
  deposited or held shall be the principal amount or redemption price of such
  Bonds and all unpaid interest thereon to the redemption date; or

         (b)   nonprepayable, noncallable Government Obligations, the
  principal of and the interest on which when due will provide money sufficient
  to pay the principal or redemption price of and all unpaid interest to
  maturity, or to the redemption date, as the case may be, on the Bonds to be
  paid or redeemed, as such principal or redemption price and interest become
  due, provided that, in the case of Bonds which are to be redeemed prior to the
  maturity thereof, notice of such redemption shall have been given as provided
  in Article IV or provision satisfactory to the Trustee shall have been made
  for the giving of such notice;

provided, in each case, that the Trustee shall have been irrevocably instructed
(by the terms of this Indenture or by Written Request of the Authority) to apply
such money to the payment of such principal or redemption price and interest
with respect to such Bonds.

                                   ARTICLE XI

                                  MISCELLANEOUS

         Section 11.01. Successors of Authority. All the covenants,
stipulations, promises and agreements in this Indenture contained, by or on
behalf of the Authority, shall bind and inure to the benefit of its successors
and assigns, whether so expressed or not. If any of the powers or duties of the
Authority shall hereafter be transferred by any law of the State, and if such
transfer shall relate to any matter or thing permitted or required to be done
under this Indenture by the Authority, then the body or official of the State
who shall succeed to such powers or duties shall act and be obligated in the
place and stead of the Authority as provided in this Indenture.

         Section 11.02. Limitation of Rights to Parties and Bondholders. Nothing
in this Indenture or in the Bonds expressed or implied is intended or shall be
construed to give to any person other than the Authority, the Trustee, the
Registrar, the Paying Agent, the Borrower and the holders of the Bonds issued
hereunder any legal or equitable right, remedy or claim under or in respect of
this Indenture or any covenant, condition or provision therein or herein
contained; and all such covenants, conditions and provisions are and shall be
held to be for the sole and exclusive benefit of the Authority, the Trustee, the

                                       51
<PAGE>

Registrar, the Paying Agent, the Borrower and the holders of the Bonds issued
hereunder.

         Section 11.03. Waiver of Notice. Whenever in this Indenture the giving
of Notice by Mail or otherwise is required, the giving of such notice may be
waived in writing by the person entitled to receive such notice and in any such
case the giving or receipt of such notice shall not be a condition precedent to
the validity of any action taken in reliance upon such waiver.

         Section 11.04. Separability of Invalid Provisions. In case any one or
more of the provisions contained in this Indenture or in the Bonds shall for any
reason be held to be invalid, illegal or unenforceable in any respect, such
invalidity, illegality or unenforceability shall not affect any other provision
of this Indenture, but this Indenture shall be construed as if such invalid or
illegal or unenforceable provision had never been contained herein.

         Section 11.05. Notices. It shall be sufficient service of any notice,
request, complaint, demand or other paper on the Authority, the Trustee, the
Borrower, the Registrar or the Paying Agent if the same shall be duly mailed
by first class mail, postage prepaid, addressed as follows:

  To the Authority:          California Pollution Control
                               Financing Authority
                             915 Capitol Mall, Room 470
                             Sacramento, California 95814
                             Attn:  Executive Director

         To the Trustee:          U.S. Bank, a National Banking Association
         Registrar and            107 South Main Street, Suite 303
         Paying Agent             Salt Lake City, Utah 84111
                                  Attn:  Corporate Trust Department

         To the Borrower:         Laidlaw Environmental Services, Inc.
                                  1301 Gervais Street, Suite 300
                                  Columbia, South Carolina 29201
                                  Attn: Chief Financial Officer

The Authority, the Trustee, the Borrower, the Registrar and the Paying Agent
may, by notice given hereunder, designate any further or different addresses to
which subsequent notices, certificates or other communications shall be sent. A
duplicate copy of each notice, certificate or other communication given
hereunder by the Authority or the Trustee to the other shall also be given to
the Borrower. Unless otherwise requested by the Authority, the Trustee, the
Borrower, the Registrar or the Paying Agent, any notice required to be given
hereunder in writing may be given by any form of telephonic or electronic
transmission capable of making a written record. Each such party shall file

                                       52
<PAGE>

with the Trustee information appropriate to receiving such form of telephonic or
electronic transmission.

         Section 11.06. Evidence of Rights of Bondholders.

         (a) Any request, consent or other instrument required by this
Indenture to be signed and executed by Bondholders may be in any number of
concurrent writings of substantially similar tenor and may be signed or
executed by such Bondholders in person or by agent or agents duly appointed in
writing. Proof of the execution of any such request, consent or other
instrument or of a writing appointing any such agent, shall be sufficient for
any purpose of this Indenture and shall be conclusive in favor of the Trustee,
the Registrar and the Authority if made in the manner provided in this Section.

         (b) The fact and date of the execution by any person of any such
request, consent or other 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 of any jurisdiction, authorized by the laws thereof to take
acknowledgments of deeds, certifying that the person signing such request,
consent or other instrument or writing acknowledged to him or her the execution
thereof.

         (c) The ownership of registered Bonds shall be proved by the Bond
register maintained by the Registrar pursuant to Section 2.04 hereof. The fact
and the date of execution of any request, consent or other instrument may also
be proved in any other manner which the Trustee may deem sufficient. The Trustee
may nevertheless, in its discretion, require further proof in cases where it may
deem further proof desirable.

         (d) Any request, consent or vote of the holder of any Bond shall bind
every future holder of the same Bond and the holder of any Bond issued in
exchange therefor or in lieu thereof, in respect of anything done or suffered to
be done by the Trustee or the Authority in pursuance of such request, consent or
vote.

         (e) Except as otherwise provided herein, in determining whether the
holders of the requisite aggregate principal amount of Bonds have concurred in
any demand, request, direction, consent or waiver under this Indenture, Bonds
which are owned by the Authority, by the Borrower or by any other direct or
indirect obligor on the Bonds, or by any person directly or indirectly
controlling or controlled by, or under direct or indirect common control with,
the Authority, the Borrower, or any other direct or indirect obligor on the
Bonds, shall be disregarded and deemed not to be Outstanding for the purpose of
any such determination, provided that, for the purpose of determining whether
the Trustee shall be protected in relying on any such demand, request,
direction, consent or waiver, only Bonds which the Trustee knows to be so owned
shall be disregarded. Bonds so owned which have been pledged in good

                                       53
<PAGE>

faith may be regarded as Outstanding for the purposes of this subsection (e) if
the pledgee shall certify to the Trustee the pledgee's right to vote such Bonds
and that the pledgee is not a person directly or indirectly controlling or
controlled by, or under direct or indirect common control with, the Authority,
the Borrower or any other direct or indirect obligor on the Bonds. In case of a
dispute as to such right, any decision by the Trustee taken upon the advice of
counsel shall be full protection to the Trustee.

         (f) In lieu of obtaining any demand, request, direction, consent or
waiver in writing, the Trustee may call and hold a meeting of the Bondholders
upon such notice and in accordance with such rules and regulations, including
the right of the Bondholders to be represented and vote by proxy, as the Trustee
considers fair and reasonable for the purpose of obtaining any such action.

         Section 11.07. Waiver of Personal Liability. No member, officer, agent
or employee of the Authority, and no officer, official, agent or employee of the
State or any department, board or agency of the State shall be individually or
personally liable for the payment of the principal of or interest on the Bonds
or be subject to any personal liability or accountability by reason of the
issuance of the Bonds; but nothing herein contained shall relieve any such
member, officer, agent or employee from the performance of any official duty
provided by law or by this Indenture.

         Section 11.08. Publication of Notices. Any publication of notice to be
made under the provisions of this Indenture may be made in each instance upon
any day, and, except as provided in Section 10.03, no such publication shall be
required if such notice is given by first class mail to the holders of all Bonds
then Outstanding.

         Section 11.09. Governing Law; Venue. This Indenture shall be construed
in accordance with and governed by the Constitution and laws of the State
applicable to contracts made and performed in the State. This Indenture shall be
enforceable in the State, and any action arising out of this Indenture shall be
filed and maintained in the Sacramento County Superior Court, Sacramento,
California, unless the Authority waives this requirement.

         Section 11.10. Execution in Several Counterparts. This Indenture may be
executed in any number of counterparts and each of such counterparts shall for
all purposes be deemed to be an original; and all such counterparts, or as many
of them as the Authority and the Trustee shall preserve undestroyed, shall
together constitute but one and the same instrument.

         Section 11.11. Reserved.

                                       54
<PAGE>

         Section 11.12. Continuing Disclosure. Pursuant to Section 5.10 of the
Agreement, the Borrower shall undertake the continuing disclosure requirements
for the Bonds as promulgated under S.E.C. Rule 15c2-12, as it may from time to
time hereafter be amended or supplemented, and the Authority shall have no
liability to the holders of the Bonds or any other person with respect to such
disclosure matters. Notwithstanding any other provision of this Indenture,
failure of the Borrower to comply with the requirements of Rule 15c2-12
applicable to the Bonds, as it may from time to time hereafter be amended or
supplemented, shall not be considered an Event of Default hereunder or under the
Agreement; however, the Trustee may (and, at the request of the Placement Agent
or the holders of at least 25% aggregate principal amount of Outstanding Bonds
and upon receipt of indemnity satisfactory to the Trustee, shall) or any
Bondholder or beneficial owner (within the meaning of Rule 15c2-12) of any Bonds
may take such actions as may be necessary and appropriate, including seeking
mandate or specific performance by court order, to cause the Borrower to comply
with its obligations under Section 5.10 of the Agreement.

         Section 11.13. Opinions of Bond Counsel. For so long as Orrick,
Herrington & Sutcliffe LLP (or its successor) is a nationally recognized Bond
Counsel, whenever in this Indenture it is required that prior to the taking of
any action (including but not limited to any modifications of arbitrage
covenants contained in Section 6.06 hereof) an opinion of Bond Counsel is
required to be delivered to the effect that such action will not adversely
affect the Tax-Exempt status of the Bonds, and such opinion is not given by
Orrick, Herrington & Sutcliffe LLP, the opinion of Bond Counsel shall instead
affirmatively state, in a manner acceptable to the Authority and the Trustee,
that interest on the Bonds is Tax-Exempt and will remain so after the action in
question. This Section shall apply in the same fashion with respect to the
affirmative opinion of any such successor Bond Counsel.

                                       55
<PAGE>

         IN WITNESS WHEREOF, the Authority has caused this Indenture to be
signed in its name and attested by its duly authorized officers, and the
Trustee, in token of its acceptance of the trust created hereunder, has caused
this Indenture to be signed in its name by its duly authorized signatory, all as
of the day and year first above written.

                                          CALIFORNIA POLLUTION CONTROL
                                            FINANCING AUTHORITY
                                          By Matt Fong, Chairman

                                          By
                                            -----------------------------------
                                                         Deputy

Attest:

----------------------------------
     Executive Director

                                          U.S. BANK, a national banking
                                          association, as Trustee

                                          By
                                             ---------------------------------
                                                   Authorized Officer

                                       56
<PAGE>

                                    EXHIBIT A

                                 [FORM OF BOND]

                                       A-1
<PAGE>

$19,500,000                                                          No.RA-1

                CALIFORNIA POLLUTION CONTROL FINANCING AUTHORITY
                    POLLUTION CONTROL REFUNDING REVENUE BOND
                     (LAIDLAW ENVIRONMENTAL SERVICES, INC.)
                                  1997 SERIES A

                  NEITHER THE FAITH AND CREDIT NOR THE TAXING POWER OF THE STATE
                  OF CALIFORNIA OR ANY LOCAL AGENCY OR POLITICAL SUBDIVISION
                  THEREOF IS PLEDGED TO THE PAYMENT OF THE PRINCIPAL OF OR
                  INTEREST ON THIS BOND.

INTEREST RATE        DATED DATE        MATURITY DATE                  CUSIP

    6.70%           July 1, 1997        July 1, 2007                130534XK1

REGISTERED HOLDER: CEDE & CO.

PRINCIPAL AMOUNT:  NINETEEN MILLION FIVE HUNDRED THOUSAND
                   DOLLARS

         CALIFORNIA POLLUTION CONTROL FINANCING AUTHORITY, a public
instrumentality and political subdivision of the State of California (the
"Authority"), for value received, hereby promises to pay (but only out of
Revenues as hereinafter provided) to the registered holder (the "holder")
identified above or registered assigns, on the maturity date set forth above,
the principal amount set forth above and to pay (but only out of the sources
hereinafter provided) interest on the balance of said principal amount from time
to time remaining unpaid from and including the date hereof (as provided herein)
until payment of said principal amount has been made or duly provided for, at
the interest rate set forth above, and to pay (but only out of the source
hereinafter provided) interest on overdue principal at the rate borne by this
Bond, except as the provisions hereinafter set forth with respect to redemption
or acceleration prior to maturity may become applicable hereto.

         The principal portion of this Bond is payable at final maturity or
earlier redemption in lawful money of the United States of America at the
corporate trust office of U.S. Bank, a national banking association, Salt Lake
City, Utah, or its successors in trust (the "Trustee"), which office is
initially located at 107 South Main Street, Suite 303, Salt Lake City, Utah
84111, Attention: Corporate Trust Department. Interest payments on this Bond,
shall be made by the Trustee as paying agent (the "Paying Agent"), on each July
1 and January 1, or if such day is not a business day, the immediately
succeeding Business Day, (as hereinafter defined), commencing January 1, 1998
(an "Interest Payment Date") to the person appearing on the bond registration

                                       A-2
<PAGE>

books of the Registrar as the registered holder hereof as of the close of
business on the Record Date (as hereinafter defined), such interest to be paid
by the Paying Agent to such registered holder (i) in the event this Bond is held
in book-entry form, in immediately available funds on the Interest Payment Date
(as hereinafter defined) in accordance with the Representation Letter; and (ii)
in the event this Bond is not held in book-entry form, (A) in immediately
available funds (by wire transfer or by deposit to the account of the holder of
this Bond if such account is maintained with the Paying Agent), according to the
instructions given by such holder to the Registrar or (B) in all other cases, by
check mailed by first class mail to the holder at such holder's address as it
appears as of the Record Date on the registration books of the Registrar;
except, in each case, that, if and to the extent that there shall be a default
in the payment of the interest due on such Interest Payment Date, such defaulted
interest shall be paid to the holders in whose name this Bond is registered as
of a special record date to be fixed by the Trustee. The term "Record Date"
means the fifteenth day (whether or not a Business Day) of the month preceding
such Interest Payment Date. The term "Business Day" means a day on which banks
located in the cities in which the principal offices of the Trustee, the
Registrar and the Paying Agent are located are not required or authorized to be
closed and on which the New York Stock Exchange is not closed.

         This Bond is one of a duly authorized issue of bonds of the Authority
designated as the "California Pollution Control Financing Authority Pollution
Control Refunding Revenue Bonds (Laidlaw Environmental Services, Inc.) 1997
Series A" (the "Bonds"), limited in aggregate principal amount as provided in,
and issued under and secured by, an Indenture of Trust, dated as of July 1, 1997
(the "Indenture"), between the Authority and the Trustee. Reference is hereby
made to the Indenture and all indentures supplemental thereto for a description
of the rights thereunder of the holders of the Bonds, of the nature and extent
of the security, of the rights, duties and immunities of the Trustee and of the
rights and obligations of the Authority thereunder, to all of the provisions of
which Indenture the holder of this Bond, by acceptance hereof, assents and
agrees. All capitalized terms used and not otherwise defined herein shall have
the meanings for such terms as are set forth in the Indenture.

         The Bonds are authorized to be issued pursuant to the provisions of the
California Pollution Control Financing Authority Act, being Division 27
(commencing at section 44500) of the California Health and Safety Code, as
supplemented and amended (the "Act"). The Bonds are limited obligations of the
Authority and, as and to the extent set forth in the Indenture, are payable
solely from, and secured by a pledge of and lien on, the Revenues, consisting
primarily of installment repayments made by Laidlaw Environmental Services, Inc.
(the "Borrower") under the terms of a Loan Agreement, dated as of July 1, 1997
(the

                                       A-3
<PAGE>

"Agreement"), between the Authority and the Borrower. The Bonds are all issued
under and equally and ratably secured by and entitled to the benefits of the
Indenture, including the security of a pledge and assignment of certain revenues
and receipts derived by the Authority pursuant to the Agreement and from any
other moneys held by the Trustee under the Indenture for such purpose, and there
shall be no other recourse against the Authority or any property now or
hereafter owned by it.

         THE BONDS SHALL NOT CONSTITUTE A DEBT OR LIABILITY, OR A PLEDGE OF THE
FAITH AND CREDIT, OF THE STATE OF CALIFORNIA, BUT SHALL BE PAYABLE SOLELY FROM
THE FUNDS HEREIN PROVIDED THEREFOR. NO OWNER OF THIS OR ANY OTHER BOND SHALL
HAVE ANY RIGHT TO DEMAND PAYMENT OF THE PRINCIPAL OF, PREMIUM, IF ANY, OR
INTEREST ON, THE BONDS BY THE AUTHORITY, THE STATE OR ANY POLITICAL SUBDIVISION
THEREOF, OUT OF ANY FUNDS TO BE RAISED BY TAXATION OR APPROPRIATION.

         The Bonds are subject to optional, mandatory and mandatory sinking fund
redemption prior to maturity upon mandatory or extraordinary optional prepayment
by the Borrower of amounts due under the Agreement, at the times, in the manner
and at the prices set forth in the Indenture.

         Notice of any extraordinary optional or mandatory redemption shall be
given by first-class mail not less than 30 days nor more than 60 days prior to
the date fixed for redemption to, among others, the holders of Bonds to be
redeemed at their addresses appearing on the registration books of the
Registrar. If less than all of the Bonds are to be redeemed, the particular
Bonds to be redeemed shall be selected as provided in the Indenture.

         This Bond shall bear interest from the last date to which interest has
been paid in full or duly provided for on this Bond, or, if no interest has been
paid or duly provided for on this Bond, from the Dated Date. Interest on the
Bonds shall be computed upon the basis of a 360-day year, consisting of twelve
30-day months.

         This Bond shall be deliverable in the form of a registered Bond without
coupons in the denominations of $1,000,000 or any integral of $5,000 thereafter,
until such time (if any) as a Rating Agency assigns a Single A Rating (as
defined in the Indenture) to the Bonds, in which case, Bonds shall be
deliverable in denominations of $100,000 or any multiple of $5,000 in excess of
that amount (herein "Authorized Denominations").

         No member, officer, agent or employee of the Authority, and no officer,
official, agent or employee of the State of California or any department, board
or agency of the State of California shall be individually or personally liable
for the payment of the principal of or interest on the Bonds or be

                                       A-4
<PAGE>

subject to any personal liability or accountability by reason of the issuance of
the Bonds, and all such liability of any such member, officer, agent or employee
as such is hereby expressly waived and released as a condition of and in
consideration for the execution of the Indenture and the issuance of any of the
Bonds.

         The holder of this Bond shall have no right to enforce the provisions
of the Indenture or to institute action to enforce the covenants therein, or to
take any action with respect to any Event of Default (as defined in the
Indenture) under the Indenture, or to institute, appear in or defend any suit or
other proceedings with respect thereto, except as provided in the Indenture. If
an Event of Default occurs and is continuing, the principal of all Bonds then
outstanding issued under the Indenture may be declared due and payable upon the
conditions and in the manner and with the effect provided in the Indenture.

         Subject to the limitations and upon payment of the charges, if any,
provided in the Indenture, Bonds may be exchanged at the principal office of the
Trustee for a like aggregate principal amount of Bonds of like tenor in
Authorized Denominations.

         This Bond is transferable by the holder hereof, in person, or by its
attorney duly authorized in writing, at the principal office of the Registrar,
but only in the manner, subject to the limitations and upon payment of the
charges provided in the Indenture, and upon surrender and cancellation of this
Bond. Upon such transfer a new fully registered Bond or Bonds of like tenor in
Authorized Denominations, for the same aggregate principal amount, will be
issued to the transferee in exchange herefor.

         The Authority, the Registrar, the Trustee, the Paying Agent and any
agent of the Authority, the Registrar, the Trustee or the Paying Agent may treat
the person in whose name this Bond is registered as the holder hereof for the
purpose of receiving payment as herein provided and for all other purposes,
whether or not this Bond be overdue, and neither the Authority, the Registrar,
the Trustee, the Paying Agent nor any such agent shall be affected by notice to
the contrary.

         The Indenture contains provisions permitting the Authority and the
Trustee, with the consent of the holders of a 662/3% in aggregate principal
amount of the Bonds at the time outstanding, evidenced as provided in the
Indenture, to execute supplemental indentures adding any provisions to, or
changing in any manner, or eliminating any of the provisions of, the Indenture;
provided, however, that no such supplemental indenture shall (1) extend the
fixed maturity of any Bond or reduce the rate of interest thereon or extend the
time of payment of interest, or reduce the amount of the principal thereof,
without the consent of the holder of each Bond so affected, or (2) reduce

                                       A-5
<PAGE>

the aforesaid percentage of holders of Bonds whose consent is required for the
execution of such supplemental indentures, or permit the creation of any lien on
the Revenues prior to or on a parity with the lien of the Indenture, except as
permitted therein, or permit the creation of any preference of any Bondholder
over any other Bondholder, except as permitted in the Indenture, or deprive the
holders of the Bonds of the lien created by the Indenture upon the Revenues,
without the consent of the holders of all the Bonds then Outstanding. The
Indenture also contains provisions permitting the Authority and the Trustee,
without the consent of any holders of the Bonds, to execute supplemental
indentures for certain purposes specified in the Indenture.

         The Indenture prescribes the manner in which it may be discharged and
after which the Bonds shall no longer be secured by or entitled to the benefits
of the Indenture, except for the purposes of registration and exchange of Bonds
and of payment of the principal of, and interest on the Bonds as the same become
due and payable, including a provision that under certain circumstances the
Bonds shall be deemed to be paid if Government Obligations maturing as to
principal and interest in such amounts and at such times as to insure the
availability of sufficient moneys to pay the principal of, and interest on the
Bonds and all necessary and proper fees, compensation and expenses of the
Trustee, shall have been deposited with the Trustee.

         It is hereby certified that all of the conditions, things and acts
required to exist, to have happened and to have been performed precedent to and
in the issuance of this Bond do exist, have happened and have been performed in
due time, form and manner as required by the Act and by the Constitution and
statutes of the State of California and that the amount of this Bond, together
with all other indebtedness of the Authority, does not exceed any limit
prescribed by the Constitution or statutes of the State of California.

         This Bond shall not be entitled to any benefit under the Indenture, or
become valid or obligatory for any purpose, until the certificate of
authentication hereon endorsed shall have been signed by the Registrar.

                                       A-6
<PAGE>

         IN WITNESS WHEREOF, the Authority has caused this Bond to be executed
in its name and on its behalf by the facsimile signature of its Chairman and
attested by the facsimile signature of its Executive Director and its seal to be
reproduced thereon, all as of the Dated Date set forth above.

                                      CALIFORNIA POLLUTION CONTROL
                                      FINANCING AUTHORITY

                                      By
                                         --------------------------------
                                                     Chairman

ATTEST:

----------------------------------
    Executive Director

                                       A-7
<PAGE>

         Unless this certificate is presented by an authorized representative of
The Depository Trust Company, a New York corporation ("DTC"), to Issuer or its
agent for registration of transfer, exchange, or payment, and any certificate
issued is registered in the name of Cede & Co. or in such other name as is
requested by an authorized representative of DTC (and any payment is made to
Cede & Co. or to such other entity as is requested by an authorized
representative of DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL inasmuch as the registered owner
hereof Cede & Co., has an interest herein.

                                       A-8
<PAGE>

                          CERTIFICATE OF AUTHENTICATION

                  This Bond is one of the Bonds described in the
within-mentioned Indenture of Trust.

Date of Authentication:
                       --------------------

                                              U.S. BANK, a national banking
                                              association, as Registrar

                                              By
                                                  ---------------------------
                                                    Authorized Signatory

                                  ABBREVIATIONS

         The following abbreviations, when used in the inscription on the face
of the within bond and in the assignment below, shall be construed as though
they were written out in full according to applicable laws or regulations.

                    TEN COM--               as tenants in common

                    TEN ENT--               as tenants by the entireties

                    JT TEN--                as joint tenants with right of
                                            survivorship and not as tenants in
                                            common

                    Additional abbreviations may also be used
                          though not in the above list.

                    UNIF GIFT/TRAN MIN ACT--        Custodian
                                            -------            ---------------
                                             (Cust)                 (Minor)
                                       Under Uniform Gifts/Transfer to
                                       Minors Act

                                       ---------------------------------------
                                                    (State)

                                       A-9
<PAGE>

                                   ASSIGNMENT

                  FOR VALUE RECEIVED the undersigned hereby sells,
assigns and transfers unto
                            ----------------------------------------------------

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

                         (Please Print or Typewrite Name
                            and Address of Assignee)

(Insert Social Security or other Identifying Number of Assignee)

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

the within Bond and hereby irrevocably constitutes and appoints
________________________________________________________________ attorney to
register the transfer of said Bond on the books kept for registration thereof,
with full power of substitution in the premises.

Dated:
        ----------------------------
Signature:
           -------------------------

SIGNATURE GUARANTEED:

-------------------------------------------------------
NOTICE:           Signature guarantee shall be made
                  by a guarantor institution
                  participating in the Securities
                  Transfer Agents Medallion Program
                  or in such other guarantee program
                  acceptable to the Registrar.

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

                                      A-10
<PAGE>

                                    EXHIBIT B

                               TRUSTEE CERTIFICATE

Name of Trust Officer
Bank Address

                                 Principal       Bonds Outstanding
1. Name of Bond Issue          Amount Issued  [6/30/__] or [12/31/__]

2. During the past six months, did the Borrower make all required payments to
the Trustee at the proper time and in the manner required by the Indenture?
Yes       No
   -----     -----

If no, please explain on a separate page.

3. If the Borrower failed to make required payments, please attach copies of any
correspondence between the Trustee and the Borrower discussing the failure and
any steps to correct such failure.

4. Has the Trustee received a copy of the latest annual financial statements of
the Borrower within 120 days of the close of the Borrower's fiscal year?
Yes        No
    -----     -----

If no, please explain what steps have been taken to secure them.

5. Has the Trustee received a certificate of an officer of the Borrower,
signed within 120 days of the close of the fiscal year, stating whether there
exists any default under the terms of the Indenture, and if a default exists,
what steps will be taken to correct the default?
Yes        No
    -----    -----

If no, please explain what steps have been taken to secure it.

6. If a letter of credit or other credit enhancement supports this bond issue,
will such letter of credit or other credit enhancement continue in full force
during the next 12 months?
 Yes         No         Not Applicable
     -----      -----

If no, please explain on a separate paper.

By                                       Date
   ---------------------------------           -------------------------------
   Authorized Signature

Title                                    Phone No.                          ]
     ------------------------------                -------------------------

                                       B-1EX-4.T
                       PROMISSORY NOTE DATED MAY 15, 1997

                                 PROMISSORY NOTE

$60,000,000 U.S. Dollars                                          May 15, 1997

1.    COVENANT TO PAY.

      1.1 FOR VALUE RECEIVED, Laidlaw Environmental Services, Inc., a Delaware
corporation ("Borrower"), hereby promises to pay to the order of WESTINGHOUSE
ELECTRIC CORPORATION, a Pennsylvania corporation, its successors and assigns
("WEC"), the principal sum of Sixty Million U.S. Dollars ($60,000,000), or so
much thereof as may be outstanding hereunder, together with interest on the
principal balance from time to time outstanding, from the date hereof, at the
fluctuating rate of the six month London Interbank Offered Rates ("6-Month
LIBOR") as determined on the First day of Such Interest Period appearing on
Bloomberg Page "LIBOR06 (Index) HP" two Business Days prior to the beginning of
such Interest Period ("Contract Rate"). In the event that such rate does not
appear on such Bloomberg Page, 6-Month LIBOR shall be determined by reference to
such other publicly available service for displaying 6-Month LIBOR as may be
agreed upon by WEC and the Borrower.

      1.2. All interest accruing hereunder shall be computed by the "exact
method," that is, by multiplying the Contract Rate by the average daily
principal balance outstanding divided by 365, multiplied by the actual number of
days interest has accrued.

      1.3. From and after maturity hereof, whether by acceleration or otherwise,
this Note shall bear interest at a rate per annum equal to the Contract Rate
plus five percent (5%), but not to exceed the highest rate permitted by law (the
"Default Rate").

      1.4  Borrower agrees to pay at the execution of this Note the accrued
interest from the last scheduled interest pay date until the execution of this
Note due under i) the 7.75% Senior Unsecured Debentures of Rollins Environmental
Services, Inc. and ii) the 7.25% Convertible Subordinated Debentures of Rollins
Environmental Services, Inc. both currently held by WEC.

2.    PAYMENT.

      2.1. The principal balance of this Note, together with all accrued and
unpaid interest hereunder, and all unpaid late charges (if any), shall be due
and payable on May 15, 2003. Interest on the outstanding principal balance of
this Note computed according to the exact

                                       -1-

<PAGE>

method as set forth above shall be due and payable semi-annually ("Interest
Period") on May 30 and November 30 of each year with the first payment being
made on November 30, 1997, including the date of payment of this Note in full.
All payments hereunder shall be made in lawful money of the United States of
America, in immediately available funds, at 11 Stanwix Street, Pittsburgh,
Pennsylvania 15222, unless WEC notifies Borrower in writing of a different
address to which payments should be made.

      2.2. If any payment required hereunder is not paid within fifteen (15)
days after it is due, a late charge of two percent (2%) of the amount of such
payment shall be paid by Borrower. All payments made on this Note shall be
applied first to any costs and expenses for which Borrower is obligated to
reimburse WEC, then to accrued and unpaid late charges, then to accrued and
unpaid interest and the remainder to principal.

3.    MANDATORY PAYMENTS.

      Borrower shall pay to WEC $10,000,000 as a principal reduction on both the
fourth and fifth anniversary dates of this Note. Such payments shall be in U.S.
Dollars in immediately available funds.

4.    INTEREST LIMITATION.

      In no contingency or event whatsoever, whether by acceleration of maturity
of the debt evidenced hereby or otherwise, shall the amount paid or agreed to be
paid to WEC for the use, forbearance or detention of the money advanced or to be
advanced hereunder exceed the highest lawful rate permissible under the laws of
the Commonwealth of Pennsylvania or the United States of America as applicable
to Borrower. If, from any circumstances whatsoever, fulfillment of any provision
hereof or of any other agreement evidencing or securing the debt, at the time
performance of such provisions shall be due, shall involve the payment of
interest in excess of that authorized by law, the obligation to be fulfilled
shall be reduced to the limit so authorized by law, and if from any
circumstances, WEC shall ever receive as interest an amount which would exceed
the highest lawful rate applicable to Borrower, such amount which would be
excessive interest shall be applied to the reduction of the unpaid principal
balance of the debt evidenced hereby and not to the payment of interest. All
sums paid to WEC for the use, forbearance or detention of the money advanced or
to be advanced hereunder shall, to the extent permitted by applicable law, be
amortized, prorated, allocated and spread throughout the full stated term of
this Note, so that the rate of interest on account of this Note is uniform
throughout the term hereof.

5.    DEFAULT AND REMEDIES.

      If Borrower fails to make any payment under this Note when due, then the
indebtedness evidenced by this Note, together with all other obligations of
Borrower to WEC, shall, at WEC's

                                       -2-
<PAGE>

sole option, become immediately due and payable without notice or demand of any
kind. Upon the occurrence of any such event, WEC may, in addition, exercise any
and all rights and remedies available under applicable law, all such rights and
remedies being cumulative and not exclusive of each other, and such rights and
remedies may be exercised concurrently or consecutively at WEC's sole option.

      5.1 Borrower shall be in default under this Note upon the occurrence of
the following events ("Event of Default"):

          a) Borrower fails to make any payment under this Note when due;

          b) Laidlaw, Inc. fails to maintain an investment grade rating by both
Standard & Poors, Inc. and Moody's Institutional Services, Inc.

          c) Borrower and Laidlaw fail to cause the return, release and
cancellation of the Closure LOC and the Bond LOC as provided in the Second
Amendment to the Stock Purchase Agreement of even date herewith;

          d) Borrower, or Laidlaw Chem-Waste, Inc., or Laidlaw Environmental
Services (Canada) Ltd., is in default under any credit agreement entered into in
connection with or contemporaneously with the acquisition transaction between
Rollins Environmental Services Inc. and Laidlaw, Inc. and any of its affiliates
and any refinancing of such debt;

          e) a default under any one or more indentures or instruments under
which there may be issued or by which there may be secured or evidenced any
indebtedness of the Borrower, Laidlaw Chem-Waste, Inc., Laidlaw Environmental
Services (Canada) Ltd., or Laidlaw, Inc., (including this Note) having an
aggregate principal amount outstanding of at least Cdn. $10,000,000 whether such
indebtedness now exists or shall hereafter be created, which default (i) shall
constitute a failure to make any payment of principal at maturity or (ii) shall
have resulted in the acceleration of such indebtedness so that the same shall be
or become due and payable prior to the date on which the same would otherwise
have become due and payable or (iii) shall have resulted in the enforcement of
any security for such indebtedness; provided, however, that if such default
under such indentures or instruments shall be remedied or cured by the Borrower,
Laidlaw Chem-Waste, Inc., Laidlaw Environmental Services (Canada) Ltd., or
Laidlaw, Inc. or waived by the holders of such indebtedness, then the Event of
Default thereof shall be deemed likewise to have been thereupon remedied, cured
or waived without further action upon the part of WEC;

          f) the entry by a court having jurisdiction in the premises of (A) a
decree or order for relief in respect to the Borrower, Laidlaw Chem-Waste, Inc.,
Laidlaw Environmental Services (Canada) Ltd., or Laidlaw, Inc. in an involuntary
case or proceeding under any applicable United States Federal, State or Canadian
Federal or Provincial bankruptcy,

                                       -3-
<PAGE>

insolvency, reorganization or other similar law or (B) a decree or order
adjudging the Borrower, Laidlaw Chem-Waste, Inc., Laidlaw Environmental Services
(Canada) Ltd., or Laidlaw, Inc. a bankrupt or insolvent, or approving as
properly filed a petition seeking reorganization, arrangement (other than an
arrangement pursuant to Section 192 of the Canada Business Corporations Act or
any successor provision to such section or similar provision of any other
statute which does not compromise the claims of creditors), adjustment or
composition of or in respect of the Borrower, Laidlaw Chem-Waste, Inc., Laidlaw
Environmental Services (Canada) Ltd., or Laidlaw, Inc. under any applicable
United States Federal, State or Canadian Federal or Provincial law, or
appointing a custodian, receiver, liquidator, assignee, trustee, sequestrator or
other similar official of the Borrower, Laidlaw Chem-Waste, Inc., Laidlaw
Environmental Services (Canada) Ltd., or Laidlaw, Inc. or of 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 for relief or any such other
decree or order unstayed and in effect for a period of 60 consecutive days; or

      g) the commencement by the Borrower, Laidlaw Chem-Waste, Inc., Laidlaw
Environmental Services (Canada) Ltd., or Laidlaw, Inc. of a voluntary case or
proceeding under any applicable United States Federal, State or Canadian Federal
or Provincial bankruptcy, insolvency, reorganization or other similar law or of
any other case or proceeding to be adjudicated a bankrupt or insolvent, or in
the consent by any of them to the entry of a decree or order for relief in
respect of the Borrower, Laidlaw Chem-Waste, Inc., Laidlaw Environmental
Services (Canada) Ltd., or Laidlaw, Inc. in an involuntary case or proceeding
under any applicable United States Federal, State or Canadian Federal or
Provincial bankruptcy, insolvency, reorganization or other similar law or to the
commencement of any bankruptcy or insolvency case or proceeding against it, or
the filing by any of them of a petition or answer to consent seeking
reorganization or relief under any applicable United States Federal, State or
Canadian Federal or Provincial law, or the consent by any of them to the filing
of such petition or to the appointment of or taking possession by a custodian,
receiver, liquidator, assignee, trustee, sequestrator or other similar official
of the Borrower, Laidlaw Chem-Waste, Inc., Laidlaw Environmental Services
(Canada) Ltd., or Laidlaw, Inc. or of any substantial part of the property of
any of them, or the making by any of them of an assignment for the benefit of
creditors, or the admission by any of them in writing or its inability to pay
its debts generally as they become due, or the taking of corporate action by any
of them in furtherance of any such action.

6.    PRIORITY AND SUBORDINATION

      6.1 Borrower covenants and agrees that this Note is prior in time, right
and payment to any indebtedness of Borrower to Laidlaw, Inc. and any affiliated
entities. Borrower further covenants and agrees not to make any payment under
any indebtedness owed to Laidlaw, Inc. or its affiliates; provided however,
Borrower may i) make payments of interest on the acquisition indebtedness owed
to Laidlaw, Inc., in connection with the purchase agreement between Rollins
Environmental Services, Inc., and Laidlaw, Inc.; and ii) make payments to
Laidlaw, Inc., and its subsidiaries in connection with the providing of
administrative services to Borrower, such

                                       -4-
<PAGE>

payments to be at fair market rates similar to or below the rates Laidlaw, Inc.,
provides to its other subsidiaries. Borrower agrees not to make any payment of
principal on such acquisition financing until WEC is paid in full under this
Note.

      6.2 WEC agrees that this Note is subordinate in right, time and payment to
the initial acquisition financing incurred by Borrower in the original principal
amount of $650,000,000.

7.    MISCELLANEOUS.

      7.1. If WEC institutes legal proceedings to enforce this Note, Borrower
agrees to pay to WEC in addition to any indebtedness due and unpaid, all costs
and expenses of such proceeding, including attorney fees and expenses.

      7.2. WEC shall not by any act of omission or commission be deemed to waive
any of its rights, privileges or remedies hereunder or under the Loan Documents,
unless such waiver be in writing and signed by an authorized officer of WEC and
then only to the extent specifically set forth therein; a waiver on one occasion
shall not be construed as continuing or as a bar to or waiver of such right,
privilege or remedy on any other occasion.

      7.3. Borrower hereby waives presentment for payment, demand, notice of
nonpayment of this Note, protest and notice of protest, trial by jury in any
litigation arising out of, relating to, or connected with this Note or any
instrument given as security herefor, and consents that WEC may extend the time
of payment of any part or the whole of the debt evidenced by this Note at any
time at the request of any other person liable for said debt.

      7.4. Borrower shall remain liable for the payment of this Note, including
interest, notwithstanding any extension or extensions of time of payment, or any
indulgence of any kind or nature that WEC may grant or permit.

      7.5. If this Note is signed by more than one person, firm, corporation or
combination thereof, all of the obligations herein contained shall be joint and
several obligations of each signer hereof. The liability of each such signer
shall be absolute and unconditional and without regard to the liability of any
other party hereto.

      7.6. This Note is given and accepted as evidence of indebtedness only, and
not in payment or satisfaction of any indebtedness or obligation.

      7.7. All questions with respect to the construction of this Note and the
rights and liabilities of the parties shall be determined in accordance with the
applicable provisions of the internal laws of the Commonwealth of Pennsylvania,
without regard to the principles of conflicts of law.

                                       -5-
<PAGE>

      7.8  Time is of the essence with respect to all of Borrower's obligations
and agreements evidenced by this Note.

      7.9  This Note and all the provisions, conditions, promises and covenants
hereof shall be binding upon the Borrower, its successors and assigns, provided
that Borrower shall not assign its obligations under this Note without the
express written consent of WEC.

      7.10 The invalidity or unenforceability of any provision of this Note
shall not affect the other provisions hereof.

      7.11 The captions used herein are for convenience only and are not
intended as limiting or defining the provisions hereof.

      7.12 In any action brought with respect to this Note, the holder hereof
need not produce or file the original of this Note, but only need produce or
file a photocopy of this Note, certified by the holder to be a true and correct
copy of this Note.

      7.13 WEC's books and records with respect to all matters relating to
advances and payments, interest and late charges, if any, under this Note,
shall, in the absence of manifest error, be conclusively presumed to be
accurate.

      IN WITNESS WHEREOF, Borrower has duly executed and delivered this Note on
the date first above written.

                             LAIDLAW ENVIRONMENTAL SERVICES, INC.
                             a Delaware corporation

                             By:  /s/ Paul R. Humphreys
                                ----------------------------
                             Its: Sen. VP and CFO
                                 ---------------------------

                                       -6-
<PAGE>

                                                                      EXHIBIT A

THIS EXHIBIT A IS ATTACHED TO AND MADE A PART OF THE PROMISSORY NOTE, DATED MAY
[ ] 15, 1997, MADE BY LAIDLAW ENVIRONMENTAL SERVICES, INC. TO WESTINGHOUSE
ELECTRIC CORPORATION (THE "NOTE").

      I.    For the purposes of Section 6.2 of the Note, "subordinate and junior
in right of payment" shall mean:

            (i)   In the event that any or all amounts owing under the Senior
      Obligations have become, or have been declared to be, due and payable and
      have not been paid in accordance with their terms (except in circumstances
      when the succeeding paragraph (ii) shall be applicable), then and in any
      such event, any payment or distribution of any kind or character, whether
      in cash, property or securities, which, but for the subordination
      provisions contained herein, would otherwise be payable or deliverable to
      the holder of this Note upon or in respect of the Subordinated Obligations
      shall instead be paid over or delivered to the Senior Creditor
      Representative for the benefit of the Senior Creditors, and the holder of
      the Note shall not in any such event receive any such payment or
      distribution or any benefit therefrom unless and until the Senior
      Obligations shall have been fully paid and satisfied.

            (ii)  In the event of any liquidation or other winding-up of the
      Borrower or in the event of any receivership, insolvency, reorganization
      or bankruptcy proceedings, assignment for the benefit of creditors or any
      proceeding by or against the Borrower for any relief under any bankruptcy,
      reorganization or insolvency law or laws, Federal or state, or any law,
      Federal or state, relating to the relief of debtors, readjustment of
      indebtedness, reorganization, composition or extension of indebtedness,
      then, and in any such even, all Senior Obligations shall first be paid in
      full before any payment or distribution is made in respect of the
      Subordinated Obligations, and any payment or distribution of any kind or
      character, whether in cash, property or securities, which but for the
      subordination provisions contained herein, would otherwise by payable or
      deliverable to the Subordinated Creditor upon or in respect of the
      Subordinated Obligations, shall instead be paid over or delivered to the
      Senior Creditor Representative for the benefit of the Senior Creditors,
      and or distribution or any benefit therefrom unless and until the Senior
      Obligations shall have been fully paid and satisfied.

            (iii) If any payment, distribution or security, or the proceeds of
      any thereof, is collected or received by the Subordinated Creditor in
      respect of the Subordinated

<PAGE>

                                                                              2

      Obligations, and such collection or receipt is prohibited by paragraph (i)
      or (ii) above, the Subordinated Creditor will forthwith turn over the same
      to the Senior Creditor Representative for the benefit of the Lenders, in
      each case in the form received (except for endorsement or the assignment
      of the Subordinated Creditor when necessary) and, until so turned over,
      the same shall be held in trust by the Subordinated Creditor as the
      property of the Senior Creditors. Notwithstanding the above or anything
      else contained in this Exhibit A, so long as no event [ ] described in
      paragraph (i) or (ii) above has occurred, the Borrower shall make, and the
      Subordinated Creditor shall be entitled to receive and keep, without
      regard to these subordination provisions, [ ] all interest payments and
      principal payments [ ] when due under the Note in accordance with the
      terms thereof, and nothing herein shall require the disgorgement of any
      such payments. In addition, the payment on the date of issuance of the
      Note to Subordinated Creditor of the accrued interest due on the Rollins
      Debentures is a permitted payment.

      II.   Subject to the payment in full of all Senior Obligations, the
Subordinated Creditor shall be subrogated to the rights of the holder(s) of the
Senior Obligations (to the extent of payments or distributions previously made
to such holders pursuant to the provisions of Section I above) to receive any
and all payments or distributions [ ] made respect of the Senior [ ] Obligations
until all amounts owing on the Subordinated Obligations shall be paid in full.
No payments or distributions applicable to Senior Obligations which the
Subordinated Creditor receives by reason of being subrogated to the rights of
the holders of Senior Obligations pursuant to the provisions of this Section II
shall, as among the Borrower, its creditors other than the holder(s) of Senior
Obligations and the Subordinated Creditor, be deemed to be a payment by the
Borrower, to or for the account of the Subordinated Obligations; and for the
purposes of such subrogation, no payments or distributions to the holders of the
Senior Obligations of any cash, property or securities to which the Subordinated
Creditor would be entitled to except for these subordination provisions, and no
payment over pursuant to these subordination provisions to the holders of Senior
Obligations by the Subordinated Creditor shall, as between the Borrower and its
creditors other than the holders of Senior Obligations and the Subordinated
Obligations, be deemed to be a payment by the Borrower to or for the account of
the Senior Obligations, it being understood that these subordination provisions
are intended solely for the purpose of defining the relative rights of the
Subordinated Creditor, on the one hand, and the Senior Creditors, on the other
hand, and nothing contained in this Section or elsewhere in these subordination
provisions is intended to or shall impair, as between the Borrower and its
creditors other than the Senior Creditors and the Subordinated Creditor, the
obligation of the Borrower, which

<PAGE>

                                                                              3

is absolute and unconditional, to pay to the Subordinated Creditor, subject to
the rights of the Senior Creditors, the amounts due and owing under the
Subordinated Obligations as and when the same shall become due and payable in
accordance with their terms, or is intended to or shall affect the relative
rights of the Subordinated Creditor and creditors of the Borrower, other than
the Senior Creditor.

      III.  By acceptance of the Note the Subordinated Creditor consents that,
without the necessity of any reservation of rights against the Subordinated
Creditor, and without notice to or further assent by the Subordinated Creditor,
(a) any demand for payment of any Senior Obligation may be rescinded in whole or
in part, and any Senior Obligation may be continued, and the Senior Obligations,
or the liability of the Borrower or any other party upon or for any part
thereof, or any collateral security or guaranty therefor, or right of offset
with respect thereto, may, from time to time, in whole or in part, be renewed,
extended, modified, accelerated, compromised, waived, surrendered, or released
and (b) the Credit Agreement, the other Load Documents referred to therein, and
any other document or instrument evidencing or governing the term of any other
Senior Obligations or any other collateral security documents or guaranties or
documents in connection with the Credit Agreement or the Senior Obligations may
be amended, modified, supplemented or terminated, in whole or in part, as the
Senior Creditor may deem advisable from time to time, and any collateral
security at any time held by the Senior Creditor for the payment of any of the
Senior Obligations may be sold, exchanged, waived, surrendered or released, in
each case, all without notice to or further assent by the Subordinated Creditor,
which will remain bound under these subordination provisions, and all without
impairing, abridging, releasing or affecting the subordination provided for
herein, notwithstanding any such renewal, extension, modification, acceleration,
compromise, amendment, supplement, termination, sale, exchange, waiver,
surrender or release. By acceptance of the Note the Subordinated Creditor waives
any and all notice of the creation, modification, renewal, extension or accrual
of any of the Senior Obligations and notice of or proof of reliance by the
Senior Creditors upon these subordination provisions, and the Senior Obligations
and any of them shall conclusively be deemed to have been created, contracted or
incurred in reliance upon these subordination provisions, and all dealings
between the Borrower, on the one hand, and the Senior Creditors, on the other,
shall be deemed to have been consummated in reliance upon these subordination
provisions. By acceptance of the Note the Subordinated Creditor acknowledges and
agrees that in entering into the Credit Agreement and in making funds available
thereunder the Senior Creditors have relied upon these subordination provisions.

<PAGE>

                                                                             4

      IV.   Notwithstanding anything in this Exhibit A to the contrary, these
subordination provisions do not in any way restrict or prohibit Subordinated
Creditor's rights under that certain Guaranty Agreement in favor of the
Subordinated Creditor executed by Laidlaw, Inc. The Senior Creditor has no
rights in any of the monies which may be paid by Laidlaw, Inc. to the
Subordinated Creditor under that Guaranty, regardless of the source of such
monies, and the Subordinated Creditor is not prohibited from enforcing its
rights under the Guaranty notwithstanding this subordination. Such enforcement
and the receipt of any monies as a result thereof are not subject to this
subordination.

      V.    As used in this Exhibit A, (i) terms defined in the Note are used
herein with the meanings given such terms in the Note, (ii) the expressions
"prior payment in full," "payment in full," "paid in full," "fully paid and
satisfied" and any other similar terms or phrases when used with respect to the
Senior Obligations shall mean the indefeasible payment in full in cash, in
immediately available funds, of all of the Senior Obligations and (iii) the
following terms have the following meanings:

      "Credit Agreement": the Credit Agreement, dated as of May 9, 1997, among
      Laidlaw Chem-Waste, Inc., Laidlaw Environmental Services (Canada) Ltd.,
      Toronto Dominion (Texas) Inc., as General Administrative Agent, and the
      Lenders and other parties thereto.

      "Senior Creditors": the holders from time to time of the Senior
      Obligations.

      "Senior Creditor Representative": Toronto Dominion (Texas) Inc., as
      General Administrative Agent under the Credit Agreement, and any successor
      in such capacity.

      "Senior Obligations": all indebtedness, obligations and liabilities of the
      Borrower or any of its subsidiaries under or in connection with the Credit
      Agreement, now existing or hereafter incurred, including all obligations
      of the Borrower as guarantor under the Guarantee and Collateral Agreement
      referred to in such Credit Agreement, in each case as any such agreement
      may be amended, extended, supplemented, restated, refinanced or otherwise
      modified from time to time.

      "Subordinated Creditor": WEC and any other holder from time to time of the
      Subordinated Obligations.

      "Subordinated Obligations": all indebtedness, obligations and liabilities
      of the Borrower under or in connection with the Note, now existing or
      hereafter incurred, as the Note may be amended, extended, supplemented,
      restated, refinanced or otherwise modified from time to time.

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