Document:

EX-4.O
                          STOCK REGISTRATION STATEMENT

                                                            EXHIBIT B TO ANNEX A

                          STOCK REGISTRATION AGREEMENT

     This Stock Registration Agreement dated               , 1997 (this
"Registration Agreement"), is among Rollins Environmental Services, Inc., a
Delaware corporation ("Rollins"), Laidlaw Transportation, Inc., a Delaware
corporation ("LTI") and Laidlaw Inc., a Canadian corporation ("Laidlaw" and
together with LTI, the "Laidlaw Parties").

                              W I T N E S S E T H:

     WHEREAS, under a Stock Purchase Agreement dated as of               , 1997
(the "Stock Purchase Agreement"), among Rollins and the Laidlaw Parties, Rollins
is this date issuing to LTI (i) 120,000,000 shares (the "Rollins Common Shares")
of Common Stock, $1.00 par value per share (the "Common Stock"), of Rollins and
(ii) a 5%, 12 year $350 million principal amount, convertible, pay-in-kind
debenture (the "Rollins Convertible Debenture"), which is convertible into
shares of Common Stock and pursuant to which interest and principal payments can
be made in shares of Common Stock (collectively, the "Additional Rollins Common
Shares");

     WHEREAS, the Stock Purchase Agreement requires that this Registration
Agreement be entered into among Rollins and the Laidlaw Parties upon the
issuance to the Laidlaw Parties of such securities of Rollins; and

     WHEREAS, the parties hereto (the "Parties") deem it desirable to enter into
this Registration Agreement to establish certain rights and restrictions with
respect to the management of the Company and the voting, sale and registration
of the shares of Common Stock,

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Parties agree that:

                                   ARTICLE I
                                  DEFINITIONS

     1.1. Definitions.  In this Registration Agreement:

          "Affiliate" means, with respect to any Person, another Person that
     directly, or indirectly through one or more intermediaries, controls, is
     controlled by or is under common control with such Person, with the terms
     "control" and "controlled" meaning, for purposes of this definition, the
     power to direct the management and policies of a Person, directly or
     indirectly, whether through the ownership of voting securities or
     partnership or other ownership interests, or by contract or otherwise.

          "Canadian Securities Acts" means the applicable securities legislation
     of each of the provinces and territories of Canada, and the regulations,
     rules and policies made thereunder or issued by the Commissions
     administering such legislation, as the same may hereafter be amended or
     replaced.

          "Commissions" means the securities commissions or similar regulatory
     authorities of each of the provinces and territories of Canada and any
     successor regulatory authorities having similar powers.

          "Designated Jurisdictions" has the meaning specified in Section 2.2.

          "Elected Jurisdictions" has the meaning specified in Section 2.1.

          "Exchange Act" means the United States Securities Exchange Act of
     1934, as amended, and the rules and regulations of the SEC promulgated
     thereunder.

          "Inspectors" has the meaning specified in Section 2.4.

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          "Offering Expenses" means all expenses incidental to Rollins's
     performance of or compliance with its obligations under Section 2.2 in
     connection with the qualification by prospectus of Registrable Securities
     under any of the Canadian Securities Acts, including, without limitation,
     all filing fees, all fees and expenses of complying with the applicable
     Canadian Securities Acts, all printing and translation expenses, all fees
     and disbursements of counsel to any Laidlaw Party and all fees and
     disbursements of Canadian counsel to Rollins and any underwriting fees and
     commissions and applicable transfer taxes, if any, relating to the
     distribution of the Registrable Securities under any Canadian Securities
     Acts.

          "Offering Notice" has the meaning specified in Section 4.4.

          "Offering Registration Statement" has the meaning specified in Section
     4.4.

          "Offering Termination Date" has the meaning specified in Section 4.4.

          "Person" means an individual, corporation, partnership, association,
     joint stock company, limited liability company, governmental entity,
     business trust, unincorporated organization or other legal entity.

          "Registrable Securities" means (i) the Rollins Common Shares, (ii) the
     Rollins Convertible Debenture, (iii) the Additional Rollins Common Shares
     and (iv) any shares of Common Stock issued in connection with any stock
     dividend on, or any stock split, reclassification or reorganization of,
     shares of Common Stock referenced in subparagraphs (i), (ii) or (iii)
     above.

          "SEC" means the United States Securities and Exchange Commission or
     any successor agency.

          "Securities Act" means the United States Securities Act of 1933, as
     amended, and the rules and regulations of the SEC promulgated thereunder.

          "Selling Laidlaw Party" has the meaning specified in Section 2.4.

          "Specified Securities" has the meaning specified in Section 2.1.

                                   ARTICLE II
                              REGISTRATION RIGHTS

     2.1. Incidental Rights.  If at any time or from time to time Rollins
proposes to file (i) with the SEC a registration statement (whether on Form S-1,
S-2, or S-3, or any equivalent form then in effect) for the registration under
the Securities Act of any shares of Common Stock for sale, or (ii) a prospectus
under any of the Canadian Securities Acts in order to qualify a distribution
under any of the Canadian Securities Acts of any securities, for cash
consideration, to the public by Rollins or on behalf of one or more shareholders
of Rollins (excluding any sale of securities convertible into or exercisable for
Common Stock, and any shares of Common Stock issuable by Rollins upon the
exercise of employee stock options, or to any employee stock ownership plan, or
in connection with any acquisition made by Rollins, any securities exchange
offer, dividend reinvestment plan, employee benefit plan, corporate
reorganization, or in connection with any amalgamation, merger or consolidation
of Rollins with one or more other corporations if Rollins is the surviving
corporation), Rollins shall give the Laidlaw Parties at least 20 days' prior
written notice of the proposed filing (or if 20 days' notice is not practicable,
a reasonable shorter period of not less than seven days), which notice shall
outline the nature of the proposed distribution and the U.S. and Canadian
jurisdictions in which Rollins proposes to qualify and offer such securities
(the "Elected Jurisdictions"). On the written request of a Laidlaw Party
received by Rollins within 15 days (or within 7 days if 20 days' notice cannot
practicably be given by Rollins) after the date of Rollins's delivery to the
Laidlaw Parties of the notice of intended registration (which request shall
specify the Registrable Securities sought to be disposed of by each Laidlaw
Party and the intended method or methods by which dispositions are intended to
be made), Rollins shall, under the terms and subject to the conditions of this
Article II, at its own expense as provided in Section 4.2, (a) use its
reasonable efforts to include in the coverage of

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such U.S. registration statement (or in a separate U.S. registration statement
concurrently filed) and qualify for sale under the blue sky or securities laws
of the various states, and (b) use its reasonable efforts to effect the
qualification under the Canadian Securities Acts, in the Elected Jurisdictions
the number of Registrable Securities (herein called the "Specified Securities")
held by such Laidlaw Party and which such Laidlaw Party has so requested to be
registered or qualified for distribution, to the extent required to permit the
distribution (in accordance with the intended method or methods thereof as
aforesaid) in the Elected Jurisdictions requested by such Laidlaw Party of such
Registrable Securities.

     If the distribution proposed to be effected by Rollins involves an
underwritten offering of the securities being so distributed by or through one
or more underwriters, and if the managing underwriter of such underwritten
offering indicates in writing its reasonable opinion that including all or part
of the Specified Securities in the coverage of such registration statement or in
the distribution to be effected by such prospectus will materially and adversely
affect the sale of securities proposed to be sold (which statement of the
managing underwriter shall also state the maximum number of shares, if any,
which can be sold by the Laidlaw Party requesting registration under this
Section 2.1 without materially and adversely affecting the sale of the shares
proposed to be sold), then the number of Specified Securities which the
requesting Laidlaw Party shall have the right to include in such registration
statement or to have qualified by such prospectus shall be reduced to the
maximum number of shares specified by the managing underwriter. In all cases,
priority shall be afforded to securities covered by a registration statement
and/or qualified for distribution by a prospectus filed in response to the
exercise of a demand registration or qualification right by a holder of Common
Stock other than a holder exercising rights under this Registration Agreement
and no securities proposed to be sold by such other holder shall be so reduced
until all securities proposed to be sold by all other parties have been entirely
eliminated. As to all other proposed selling shareholders of Common Stock,
including the Laidlaw Party requesting to include Registrable Securities in the
coverage of such a registration statement or prospectus, any such reduction in
the number of shares of Common Stock proposed to be sold by the selling
shareholders shall be effected on a pro rata basis in accordance with the
relationship which the number of shares of Common Stock proposed to be sold by
each selling shareholder bears to the number of shares of Common Stock proposed
to be sold by all selling shareholders.

     Rollins shall have the sole right to select any underwriters, including the
managing underwriter, of any public offering of shares of Common Stock subject
to this Section 2.1.

     Each Laidlaw Party may request to have Common Stock included in an
unlimited number of registrations, and qualified by an unlimited number of
prospectuses, under this Section 2.1. Registration rights under this Section 2.1
shall extend only to the incidental registrations of Common Stock.

     2.2. Mandatory Rights.  Upon written request of a Laidlaw Party made at any
time, Rollins shall, under the terms and subject to the conditions set forth in
this Section 2.2 and in Section 2.4, (i) at Rollins' expense, file (and use its
reasonable efforts to cause to become effective) a U.S. registration statement
covering, and use its reasonable efforts to qualify for sale under the blue sky
or securities laws of the various U.S. states as may be requested by such
Laidlaw Party (except any such state in which, in the opinion of the managing
underwriter of the offering, the failure to so qualify would not materially and
adversely affect the proposed offering), and (ii) at such Laidlaw Party's
expense, use its reasonable efforts to effect the qualification for distribution
under the Canadian Securities Acts, in accordance with the intended method or
methods of disposition set forth in that notice, such number of Registrable
Securities, as may be designated by such Laidlaw Party in its request, or that
portion thereof designated in said request for registration or qualification in
each of the Designated Jurisdictions (as defined below). A request for
registration under this Section 2.2 shall specify the number of shares to be
registered, the United States and Canadian jurisdiction in which such
registration or qualification is to be effected (the "Designated Jurisdictions")
and the proposed manner of sale, including the name and address of any proposed
underwriter; provided, that all offerings contemplated by a request for
registration under this Section 2.2 shall be underwritten offerings involving
either a distribution of Registrable Shares to the public where no single buyer,

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acting individually or with others, acquires more than 10% of such offering, or
a distribution by way of dividend or other distribution to holders of Common
Stock in the capital of Rollins where such dividend or other distribution is
made pro rata between the holders of all such classes of shares according to the
number of shares of either class held by each of them. The principal underwriter
or underwriters for any such offering shall be selected by the Laidlaw Party
requiring registration, subject to Rollins's approval, which may not
unreasonably be withheld.

     If the distribution proposed to be effected pursuant to this Section 2.2
involves an underwritten offering of the securities being so distributed by or
through one or more underwriters, and if the managing underwriter of such
underwritten offering indicates in writing its reasonable belief that including
all or part of the Registrable Securities in the coverage of such registration
statement or in the distribution to be effected by such prospectus will
materially and adversely affect the sale of the securities proposed to be sold,
then the number of securities proposed to be sold shall be reduced to the
maximum number of securities specified by the managing underwriter. In such a
case, priority shall be afforded to Registrable Securities and the securities
that are not Registrable Securities shall be completely eliminated from
inclusion in such offering before the number of Registrable Securities is
reduced.

     Rollins may delay the filing or effectiveness of any registration
statement, or any preliminary prospectus or (final) prospectus required to
effect a qualification for distribution, requested under this Section 2.2, or
delay its effectiveness, for a reasonable period (but not longer than 120 days)
if, in the sole judgment of Rollins's Board of Directors, (i) a delay is
necessary in light of pending financing transactions, corporate reorganizations
or other major events involving Rollins, or (ii) filing at the time requested
would materially and adversely affect the business or prospects of Rollins in
view of disclosures that may thereby be required. Once the cause of the delay is
eliminated, Rollins shall promptly notify the Laidlaw Parties requiring
registration or qualification, and promptly after a Laidlaw Party notifies
Rollins to proceed, Rollins shall, as required in connection with the Designated
Jurisdictions selected by the relevant Laidlaw Parties, file a registration
statement or a preliminary prospectus and/or (final) prospectus and begin
performance of its other obligations under this Section 2.2.

     The Laidlaw Parties shall be entitled to request three registrations or
qualifications under this Section 2.2 from the date hereof until the fifth
anniversary of the date hereof and three additional registrations or
qualifications under this Section 2.2 from the fifth anniversary of the date
hereof until the twelfth anniversary of the date hereof (provided that the
filing of a registration statement and a preliminary prospectus or (final)
prospectus in more than one Designated Jurisdictions in connection with a
concurrent or substantially concurrent distribution shall be deemed for the
purposes hereof to be a single registration and qualification). However, if a
Laidlaw Party requests a registration under this Section 2.2, but no
registration statement or (final) prospectus becomes effective with respect to
the Registrable Securities covered by such request, then such request shall not
count as a request for purposes of determining the number of requests for
registration or qualification the Laidlaw Parties may make under this Section
2.2.

     2.3. Registration Conditions.  Notwithstanding any other provision of this
Registration Agreement, Rollins shall not be required to effect a registration
or qualification of any securities under this Article II, or file any
post-effective amendment to such a registration statement or prospectus relating
to such a qualification:

          2.3.1. unless the requesting Laidlaw Party agrees to (a) sell and
     distribute a portion or all of its Registrable Securities in accordance
     with the plan or plans of distribution adopted by and through underwriters,
     if any, acting for Rollins, and (b) bear a pro rata share of underwriter's
     discounts and commissions;

          2.3.2. if a registration or qualification requested under Section 2.2,
     or any post-effective amendment to the registration statement and/or
     prospectus filed in connection therewith, requires, under applicable
     statutes and rules, a special audit (other than a normal fiscal year-end
     audit) of any financial statements, unless the requesting Laidlaw Party
     agrees to pay its proportionate share

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     (determined by the number of shares to be sold by such Laidlaw Party in the
     offering in proportion to the total number of shares to be sold by Rollins
     and all other participants in such offering) of the reasonable fees and
     expenses of accountants incurred in connection with the special audit and
     which would otherwise not be incurred;

          2.3.3. if, in the case of a request for registration or qualification
     under Section 2.1 or 2.2, in the reasonable opinion of counsel for Rollins,
     (i) the Registrable Securities for which registration under the Securities
     Act has been requested may be disposed of without adversely affecting the
     market price of such Registrable Securities within a comparable time frame
     without registration under the Securities Act and (ii) upon such
     disposition all legends on certificates representing such shares which
     restrict their transfer under the Securities Act and applicable state
     securities laws may be removed, and the sale by the applicable Laidlaw
     Party of any Registrable Securities for which qualification for
     distribution under any Canadian Securities Acts has been requested (a) will
     not constitute a "distribution" (or the corresponding term) under the
     applicable Canadian Securities Acts, or (b) may be effected in the method
     requested (or in a method having a substantially similar economic effect,
     as to which such counsel may make any reasonable assumption for the
     purposes of such opinion) without qualification by prospectus; provided
     that the first trade of such Registrable Securities by the purchaser
     thereof from the Laidlaw Party in such sale would not constitute a
     "distribution" (or the corresponding term) under the applicable Canadian
     Securities Acts (but for (I) any unusual effort made to prepare the market
     or to create a demand for such securities made by or on behalf of such
     purchaser), (II) any extraordinary commission or consideration paid or to
     be paid in respect of such first trade, or (III) such purchaser being a
     Person described in clause (III) of the definition of "distribution" set
     forth in section 1(1) of the Securities Act (Ontario) in relation to
     Rollins (or any corresponding provision of any other applicable Canadian
     Securities Act);

          2.3.4. if, in the case of a request for registration under Section
     2.2, other than with respect to a distribution by way of dividend or other
     distribution to holders of common stock in the capital of Laidlaw where
     such dividend or other distribution is made pro rata between the holders of
     all such classes of shares according to the number of shares of either
     class held by each of them (i) any registration statement or prospectus
     covering securities regarding which a Laidlaw Party could have exercised
     registration rights under Section 2.1 of this Registration Agreement has
     become effective under the Securities Act or, with respect to a (final)
     prospectus, a receipt has been issued therefor under the applicable
     Canadian Securities Acts within six months preceding the date of such
     request, (ii) a registration statement or prospectus requested by a Laidlaw
     Party pursuant to Section 2.2 has become effective under the Securities Act
     or, with respect to a (final) prospectus, a receipt has been issued
     therefor under the applicable Canadian Securities Acts within twelve months
     preceding the date of such request or (iii) Rollins has given notice under
     Section 2.1 of its intention to file a registration statement under the
     Securities Act or a prospectus under any Canadian Securities Acts and has
     not completed or abandoned the proposed offering; and

          2.3.5. unless Rollins has received from the Laidlaw Party requesting
     registration or qualification all information Rollins has reasonably
     requested concerning such Laidlaw Party and its method of distribution of
     its Registrable Securities, so as to enable Rollins to include in the
     registration statement or prospectus all facts required to be disclosed in
     it.

     2.4. Covenants and Procedures.  If Rollins becomes obligated under this
Article II to effect a registration or qualification of Registrable Securities
on behalf of a Laidlaw Party requesting registration or qualification under this
Article II (hereinafter called a "Selling Laidlaw Party"), then (as applicable
to the jurisdictions for which such registration or qualification is to be
made):

          2.4.1. Rollins, (i) at its expense as provided in Section 4.2, shall
     prepare and file with the SEC a registration statement covering and, as
     applicable, (ii) at its expense as provided in Section 4.2 if such
     registration is triggered pursuant to Section 2.1, or at the expense of the
     requesting Selling Laidlaw Party as provided in Section 4.3 if such
     registration is triggered pursuant to

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     Section 2.2, prepare and file with the applicable Commissions (in the
     English and French languages, as applicable) a preliminary prospectus
     qualifying such securities and such other related documents as may be
     necessary or appropriate relating to the proposed distribution, and shall
     use reasonable efforts to cause the registration statement to become
     effective and (with respect to Canadian jurisdictions) after any comments
     of the Commissions have been satisfied with respect thereto, to prepare and
     file in accordance with the relevant Canadian Securities Acts, a (final)
     prospectus in the English and French languages, as appropriate, and receive
     receipts therefor and shall take all other steps and proceedings that may
     be necessary in order to qualify the applicable Registrable Securities for
     distribution under such Canadian Securities Acts by registrants who comply
     with the relevant provisions of such Canadian Securities Acts. Rollins will
     also (a) with respect to any U.S. registration statement, file such
     post-effective amendments to the registration statement (and use reasonable
     efforts to cause it to become effective) and such supplements as are
     necessary so that current prospectuses are at all times available for a
     period of at least 90 days after the effective date of the registration
     statement or for such longer period, not to exceed 180 days, as may be
     required under the plan or plans of distribution set forth in the
     registration statement, and (b) with respect to any Canadian prospectus,
     file with the Commissions such amendments and supplements to such
     preliminary prospectus and (final) prospectus as may be necessary to comply
     with the provisions of the Canadian Securities Acts applicable to the
     proposed distribution until the earlier of (I) such time as all of
     Registrable Securities proposed to be sold thereunder have been disposed of
     in accordance with the intended method or methods of disposition by the
     Selling Laidlaw Party thereof, and (II) the expiration of a period of at
     least 90 days after the issuance by the Commissions in all applicable
     Canadian jurisdictions for the (final) prospectus or such longer period,
     not to exceed 180 days, as may be required under the plan or plans of
     distribution set forth in such (final) prospectus. Each Selling Laidlaw
     Party shall promptly provide Rollins with such information with respect to
     such Selling Laidlaw Party's Registrable Securities to be so registered and
     qualified and, if applicable, the proposed terms of their offering, as is
     required for the registration or qualification. If the Registrable
     Securities to be covered by the registration statement and/or prospectus
     are not to be sold to or through underwriters acting for Rollins, Rollins
     shall:

             (x) deliver to each Selling Laidlaw Party, as promptly as
        practicable, as many copies of preliminary prospectuses as each Selling
        Laidlaw Party may reasonably request (in which case each Selling Laidlaw
        Party shall keep a written record of the distribution of the preliminary
        prospectuses and shall refrain from delivery of the preliminary
        prospectuses in any manner or under any circumstances which would
        violate the Securities Act, the applicable Canadian Securities Acts or
        the securities laws of any other jurisdiction, including the various
        states of the United States);

             (y) deliver to each Selling Laidlaw Party, as soon as practicable
        after the effective date of the U.S. registration statement, or, as
        applicable, the date on which all applicable Commissions shall have
        issued a receipt for the Canadian (final) prospectus, and from time to
        time thereafter during the applicable period described in paragraph
        2.4.1(i) or (ii), as many copies of the relevant prospectuses (including
        any (final) prospectus as such Selling Laidlaw Party may reasonably
        request); and

             (z) in case of the happening, after the effective date of the
        registration statement and during the applicable 90 or 180 day period
        described in the second sentence of paragraph 2.4.1, of any event or
        occurrence as a result of which the prospectus (including any
        preliminary prospectus or (final) prospectus), as then in effect, would
        include an untrue statement of a material fact or omit to state any
        material fact required to be stated therein or necessary to make any
        statement therein not misleading in the light of the circumstances in
        which it was made, give each Selling Laidlaw Party written notice of the
        event or occurrence and prepare and furnish to each Selling Laidlaw
        Party, in such quantities as it may reasonably request, copies of an
        amendment of or a supplement to such prospectus as may be necessary so
        that the prospectus, as so amended or supplemented and thereafter
        delivered to

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        purchasers of the securities, will not contain any untrue statement of a
        material fact or omit to state any material fact required to be stated
        therein or necessary to make the statements therein, in the light of the
        circumstances under which they were made, not misleading.

          2.4.2. Rollins will notify each Selling Laidlaw Party of any action by
     the SEC or any Commission to suspend the effectiveness of any registration
     statement or prospectus filed pursuant hereto or the initiation or
     threatened initiation of any proceeding for such purpose or the receipt by
     Rollins of any notification with respect to the suspension of the
     qualification of the securities covered by a prospectus filed pursuant
     hereto for sale in any jurisdiction. Immediately upon receipt of any such
     notice, the Laidlaw Parties shall cease to offer or sell any Registrable
     Securities pursuant to the registration statement or prospectus in the
     jurisdiction to which such order or suspension relates. Rollins will also
     notify each Selling Laidlaw Party promptly of the occurrence of any event
     or the existence of any state of facts that, in the judgment of Rollins,
     should be set forth in such registration statement or prospectus.
     Immediately upon receipt of such notice, the Laidlaw Parties shall cease to
     offer or sell any Registrable Securities pursuant to such registration
     statement or prospectus, cease to deliver or use such registration
     statement or prospectus and, if so requested by Rollins, return to Rollins
     at Rollins's expense all copies of such registration statement or
     prospectus. Rollins will as promptly as practicable take such action as may
     be necessary to amend or supplement such registration statement or
     prospectus in order to set forth or reflect such event or state of facts
     and provide copies of such proposed amendment or supplement to each Selling
     Laidlaw Party.

          2.4.3. On or before the date on which the registration statement is
     declared effective, or a receipt is issued by all Commissions for the
     (final) prospectus, Rollins shall use its reasonable efforts to:

             (i) register or qualify (and cooperate with each Selling Laidlaw
        Party, the underwriter or underwriters, if any, and their counsel, in
        connection with the registration or qualification of) the securities
        covered by the registration statement for offer and sale under the
        securities or blue sky laws of each state and other U.S. or Canadian
        jurisdiction as any Selling Laidlaw Party or underwriter reasonably
        requests;

             (ii) use its reasonable efforts to keep each such registration or
        qualification effective, including through new filings, or amendments or
        renewals, during the period the registration statement or prospectus is
        required to be kept effective; and

             (iii) do any and all other acts or things necessary or advisable to
        enable the disposition in all such jurisdictions of the Common Stock
        covered by the applicable registration statement or prospectus, provided
        that Rollins will not be required to qualify generally to do business in
        any jurisdiction where it is not then so qualified.

          2.4.4. Rollins shall use its reasonable efforts to cause all
     Registrable Securities of a Selling Laidlaw Party included in the
     registration statement or qualified by prospectus to be listed, by the date
     of the first sale of such shares pursuant to such registration statement or
     prospectus, on each securities exchange on which the securities as then
     listed or proposed to be listed, if any.

          2.4.5. Rollins shall make generally available to each Selling Laidlaw
     Party and any underwriter participating in the offering conducted pursuant
     to the registration statement an earnings statement satisfying Section
     11(a) of the Securities Act no later than 45 days after the end of the
     12-month period beginning with the first day of Rollins's first fiscal
     quarter commencing after the effective date of the registration statement.
     The earnings statement shall cover such 12-month period. This requirement
     will be deemed to be satisfied if Rollins timely files complete and
     accurate information on Forms 10-Q, 10-K and 8-K under the Exchange Act,
     and otherwise complies with Rule 158 under the Securities Act as soon as
     practicable. In addition, in the event that Rollins shall have become a
     reporting issuer (or have the corresponding status) under any of the
     Canadian Securities Acts, Rollins shall comply with the continuous
     disclosure

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     obligations of a reporting issuer (or the obligations attendant upon such
     corresponding status) prescribed by each Canadian Securities Act under
     which it has such status.

          2.4.6. Rollins shall cooperate with each Selling Laidlaw Party and the
     managing underwriter or underwriters, if any, to facilitate the timely
     preparation and delivery of certificates (not bearing any restrictive
     legends) representing Registrable Securities to be sold under the
     registration statement or prospectus, and to enable such securities to be
     in such denominations and registered in such names as the managing
     underwriter or underwriters, if any, or the Selling Laidlaw Party, may
     request, subject to the underwriters' obligation to return any certificates
     representing unsold securities.

          2.4.7. Rollins shall use its reasonable efforts to cause Registrable
     Securities covered by the registration statement or prospectus to be
     registered with or approved by such other governmental agencies or
     authorities in the U.S. or Canada (including the registration of
     Registrable Securities under the Exchange Act) as may be necessary to
     enable the Selling Laidlaw Parties or the underwriter or underwriters, if
     any, to consummate the disposition of such securities.

          2.4.8. Rollins shall, during normal business hours and upon reasonable
     notice, make available for inspection by each Selling Laidlaw Party, any
     underwriter participating in any offering pursuant to the registration
     statement or prospectus, and any attorney, accountant or other agent
     retained by a Selling Laidlaw Party or any such underwriter (collectively,
     the "Inspectors"), all nonconfidential financial and other records,
     pertinent corporate documents, and properties of Rollins, as shall be
     reasonably necessary to enable the Inspectors to exercise their due
     diligence responsibilities and as they may reasonably consider to be
     necessary for the purpose of establishing their due diligence defense (as
     applicable) as contemplated by the Canadian Securities Acts and in order to
     enable any such underwriters to execute the certificate on any prospectus
     required pursuant to any Canadian Securities Acts to be executed by them.
     Rollins shall also cause its officers, directors, and employees to supply
     all nonconfidential information reasonably requested by any Inspector in
     connection with the registration statement.

          2.4.9. Rollins shall use its reasonable efforts to obtain a "cold
     comfort" letter and, as applicable, a "long-form comfort letter" from
     Rollins's independent public accountants, and an opinion of counsel for
     Rollins, each in customary form and covering such matters of the type
     customarily covered by cold comfort letters and long form comfort letters
     and legal opinions in connection with public offerings of securities, as
     the Selling Laidlaw Party reasonably requests, and consents from all
     parties from whom such consents would be required under the applicable
     Canadian Securities Acts.

          2.4.10. Rollins shall provide and cause to be maintained a transfer
     agent and registrar for all Registrable Securities for the term of this
     Registration Agreement.

          2.4.11. Rollins shall use all reasonable efforts to cause the
     Registrable Securities covered by the registration statement to continue to
     be listed for a period of three years after the registration statement is
     declared effective on at least one national securities exchange on which
     the Common Stock is listed.

          2.4.12. Rollins shall reasonably cooperate, at the Selling Laidlaw
     Party's expense, with the Selling Laidlaw Party participating in the
     disposition of the Registrable Securities and its respective counsel in
     connection with any filings required to be made with the National
     Association of Securities Dealers, Inc.

          2.4.13. Rollins shall make available to the managing underwriters
     certain of its officers (subject to the reasonable demands of its business)
     for the purpose of participating in one "road show" presentation in
     connection with underwritten offerings. The Selling Laidlaw Parties agree
     that they will bear all incremental expenses incurred by Rollins in
     complying with this Section 3.4.13 if such registration is triggered
     pursuant to a request under Section 2.2.

                                      A-B-8
<PAGE>

          2.4.14. Rollins shall enter into such customary agreements (including,
     if applicable, an underwriting agreement) and take such other actions as
     each Selling Laidlaw Party shall reasonably request in order to expedite or
     facilitate the disposition of the Registrable Securities; provided that
     such customary agreements, if any, shall be reasonably satisfactory in form
     and substance to Rollins. Laidlaw shall be a party to such underwriting
     agreement and may, at its option, require that Rollins make to and for the
     benefit of Laidlaw the representations, warranties and covenants of Rollins
     which are being made to and for the benefit of such underwriters and which
     are of the type customarily provided to institutional investors in
     secondary offerings.

          2.4.15. Rollins shall deliver promptly to Laidlaw and each
     underwriter, if any, copies of all correspondence between the SEC, on the
     one hand, and Rollins, its counsel or auditors, on the other hand, and all
     memoranda relating to discussions with the SEC or its staff, with respect
     to any registration statement, other than those portions of any such
     correspondence and memoranda which contain information subject to
     attorney-client privilege with respect to Rollins, and, upon receipt of
     such confidentiality agreements as Rollins may reasonably request, make
     reasonably available for inspection by any Selling Laidlaw Party covered by
     such registration statement, by any underwriter, if any participating in
     any disposition to be effected pursuant to such registration statement and
     by any attorney, accountant or other agent retained by any Selling Laidlaw
     Party or any such underwriter, all pertinent financial and other records,
     pertinent corporate documents and properties of Rollins, and cause all of
     Rollins' officers, directors and employees to supply all information
     reasonably requested by any such Selling Laidlaw Party, underwriter,
     attorney, accountant or agent in connection with such registration
     statement.

                                  ARTICLE III
                                INDEMNIFICATION

     3.1. Indemnification by Rollins.  In the event of any registration or
qualification under the Securities Act or any Canadian Securities Act by any
registration agreement or prospectus pursuant to rights herein granted of
Registrable Securities held by a Laidlaw Party who becomes a Selling Laidlaw
Party, Rollins will hold harmless such Selling Laidlaw Party and each
underwriter of such securities and each other Person, if any, who controls such
Selling Laidlaw Party or such underwriter within the meaning of the Securities
Act, against any losses, claims, damages or liabilities (including legal fees
and costs of court), joint or several, to which such Selling Laidlaw Party or
such underwriter or controlling Person becomes subject under the Securities Act,
the applicable Canadian Securities Acts or otherwise, insofar as such losses,
claims, damages or liabilities (or any actions in respect thereof) arise out of
or are based upon any untrue statement or alleged untrue statement of any
material fact contained, on its effective date, in any registration statement
under which such securities were registered under the Securities Act, or in any
related preliminary or (final) prospectus, or in any preliminary prospectus or
(final) prospectus under which such securities were qualified for distribution
under any Canadian Securities Act, or any amendment or supplement to any of the
foregoing, or which arise out of or are based upon the omission or alleged
omission to state a material fact required to be stated therein or necessary to
make the statements therein not misleading; and will reimburse such Selling
Laidlaw Party and each such underwriter and each such controlling Person for any
legal or any other expenses reasonably incurred by them in connection with
investigating or defending any such loss, claim, damage or liability; provided,
however, that Rollins shall not be liable to such Selling Laidlaw Party or its
underwriters or controlling Persons in any such case to the extent that any such
loss, claim, damage or liability arises out of or is based upon an untrue
statement or alleged untrue statement or omission or alleged omission made in
such registration statement, preliminary or (final) prospectus or such amendment
or supplement, in reliance upon and in conformity with information furnished to
Rollins through a written instrument duly executed by such Selling Laidlaw Party
or such underwriter specifically for use in the preparation thereof or results
from any improper conduct of such Selling Laidlaw Party or any such underwriter
or controlling Person.

                                      A-B-9
<PAGE>

     3.2. Indemnification by Selling Laidlaw Parties.  It shall be a condition
precedent to the obligation of Rollins to include in any registration statement
or to qualify by prospectus any Registrable Securities of a Selling Laidlaw
Party that Rollins shall have received from such Selling Laidlaw Party an
undertaking, reasonably satisfactory to Rollins and its counsel, to indemnify
and hold harmless (in the same manner and to the same extent as set forth in
Section 4.1) Rollins, each director of Rollins, each officer of Rollins who
shall sign the registration statement or prospectus and any Person who controls
Rollins within the meaning of the Securities Act, (i) with respect to any
statement or omission from such registration statement, any related preliminary
or (final) prospectus or any amendment or supplement to any of the foregoing, if
such statement or omission was made in reliance upon and in conformity with
information furnished to Rollins through a written instrument duly executed by
such Selling Laidlaw Party specifically for use in the preparation of such
registration statement, preliminary or (final) prospectus or amendment or
supplement and (ii) with respect to compliance by such Selling Laidlaw Party
with applicable laws in effecting the sale or other disposition of the
securities covered by such registration statement; provided, however, that the
aggregate amount which any such Selling Laidlaw Party shall be required to pay
pursuant to this Section 3.2 shall in no case be greater than the amount of the
net proceeds received by such Selling Laidlaw Party upon the sale of the
Registrable Securities pursuant to the registration statement giving rise to
such claim.

     3.3. Indemnification Procedures.  Promptly after receipt by an indemnified
party of notice of the commencement of any action involving a claim referred to
in the preceding Sections of this Article III, the indemnified party will, if a
resulting claim is to be made or may be made against an indemnifying party, give
written notice to the indemnifying party of the commencement of the action. If
any such action is brought against an indemnified party, the indemnifying party
will be entitled to participate in and to assume the defense of the action with
counsel reasonably satisfactory to the indemnified party, and after notice from
the indemnifying party to such indemnified party of its election to assume
defense of the action, the indemnifying party will not be liable to such
indemnified party for any legal or other expenses incurred by the latter in
connection with the action's defense. An indemnified party shall have the right
to employ separate counsel in any action or proceeding and participate in the
defense thereof, but the fees and expenses of such counsel shall be at such
indemnified party's expense unless (i) the employment of such counsel has been
specifically authorized in writing by the indemnifying party, which
authorization shall not be unreasonably withheld, (ii) the indemnifying party
has not assumed the defense and employed counsel reasonably satisfactory to the
indemnified party within 30 days after notice of any such action or proceeding
or (iii) the named parties to any such action or proceeding (including any
impleaded parties) include the indemnified party and the indemnifying party and
the indemnified party shall have been advised by such counsel that there may be
one or more legal defenses available to the indemnified party that are different
from or additional to those available to the indemnifying party (in which case
the indemnifying party shall not have the right to assume the defense of such
action or proceeding on behalf of the indemnified party), it being understood,
however, that the indemnifying party shall not, in connection with any one such
action or separate but substantially similar or related actions in the same
jurisdiction arising out of the same general allegations or circumstances, be
liable for the reasonable fees and expenses of more than one separate firm of
attorneys (in addition to all local counsel which is necessary, in the good
faith opinion of both counsel for the indemnifying party and counsel for the
indemnified party in order to adequately represent the indemnified parties) for
the indemnified party and that all such fees and expenses shall be reimbursed as
they are incurred upon written request and presentation of invoices. Whether or
not a defense is assumed by the indemnifying party, the indemnifying party will
not be subject to any liability for any settlement made without its consent. No
indemnifying party will consent to entry of any judgment or enter into any
settlement which does not include as an unconditional term the giving by the
claimant or plaintiff, to the indemnified party, of a release from all liability
in respect of such claim or litigation.

     3.4. Contribution.  If the indemnification required by this Article IV from
the indemnifying party is unavailable to or insufficient to hold harmless an
indemnified party in respect of any indemnifiable losses, claims, damages,
liabilities or expenses, then the indemnifying party shall

                                     A-B-10
<PAGE>

contribute to the amount paid or payable by the indemnified party as a result of
such losses, claims, damages, liabilities or expenses in such proportion as is
appropriate to reflect (i) the relative benefit of the indemnifying and
indemnified parties and (ii) if the allocation in clause (i) is not permitted by
applicable law, in such proportion as is appropriate to reflect the relative
benefit referred to in clause (i) and also the relative fault of the indemnified
and indemnifying parties, in connection with the actions which resulted in such
losses, claims, damages, liabilities or expenses, as well as any other relevant
equitable considerations. The relative fault of the indemnifying party and the
indemnified party shall be determined by reference to, among other things,
whether any action in question, including any untrue or alleged untrue statement
of a material fact, has been made by, or relates to information supplied by,
such indemnifying party or parties, and the parties' relative intent, knowledge,
access to information, and opportunity to correct or prevent such action. The
amount paid or payable by a party as a result of the losses, claims, damage,
liabilities and expenses referred to above shall be deemed to include any legal
or other fees or expenses reasonably incurred by such party in connection with
any investigation or proceeding. Rollins and the Laidlaw Parties agree that it
would not be just and equitable if contribution pursuant to this Section 3.4
were determined by pro rata allocation or by any other method of allocation
which does not take account of the equitable considerations referred to in the
prior provisions of this Section 3.4.

     Notwithstanding the provisions of this Section 3.4, no indemnifying party
shall be required to contribute any amount in excess of the amount by which the
total price at which the securities were offered to the public by the
indemnifying party exceeds the amount of any damages which the indemnifying
party has otherwise been required to pay by reason of an untrue statement or
omission. No Person guilty of fraudulent misrepresentation (within the meaning
of Section 11(f) of the Securities Act or the Criminal Code (Canada)) shall be
entitled to contribution from any Person who was not guilty of such a fraudulent
misrepresentation.

                                   ARTICLE IV
                                OTHER AGREEMENTS

     4.1. Other Registration Rights.  Rollins agrees that it will not grant to
any Person registration rights which would allow such Person to limit Laidlaw's
priority for the sale or distribution of Registrable Securities upon the
exercise of mandatory registration rights pursuant to Section 2.2.

     4.2. Expenses.  All expenses incurred by Rollins in connection with any
U.S. registration statement covering Registrable Securities offered by a Laidlaw
Party, including, without limitation, all registration and filing fees
(including all expenses incident to filing with the National Association of
Securities Dealers, Inc.), printing expenses, fees and disbursements of counsel
(except for the fees and disbursements of counsel for such Laidlaw Party) and of
the independent certified public accountants (except, in the case of any special
audits, if required in connection with any such registration, such Laidlaw
Party's proportionate share of its expense as provided in Section 2.3) and the
expense of qualifying such shares under state blue sky laws, shall be borne by
Rollins; provided, however, that Rollins shall not be required to pay for any
expenses of any registration proceeding begun pursuant to Section 2.2 if the
registration request is subsequently withdrawn at the request of a Laidlaw Party
(in which case such Laidlaw Party shall bear such expenses), unless the Laidlaw
Parties agree to forfeit their right to one demand registration pursuant to
Section 2.2; provided further, that if at the time of such withdrawal, such
Laidlaw Party has learned of a material adverse change in the condition,
business or prospects of Rollins from that known at the time of its request,
then such Laidlaw Party shall not be required to pay any of such expenses and
shall retain its rights pursuant to Section 2.2. Rollins's obligations under
this Section 4.2 shall apply to each registration under the Securities Act or
state blue sky legislation pursuant to Section 2.2.

     4.3. Offering Expenses.  The Laidlaw Party selling any Registrable
Securities pursuant to any prospectus filed with any Commission in connection
with the satisfaction by Rollins of its obligations under Section 2.2 shall
reimburse Rollins for all Offering Expenses reasonably incurred by or on behalf
of Rollins upon receipt by such Laidlaw Party of a written request from Rollins
in respect of same,

                                     A-B-11
<PAGE>

together with invoices outlining in reasonable detail the expenses to be borne
by the Laidlaw Party or Laidlaw Parties. In addition, the relevant Laidlaw
Parties shall be responsible for any additional expenses reasonably incurred by
Rollins as a result of such Laidlaw Parties' participation in any offering
proposed to be completed by Rollins in any Canadian jurisdiction as contemplated
in Section 2.1 upon receipt by the relevant Laidlaw Parties of a written request
from Rollins in respect of the same, together with appropriate documentation
outlining all expenses incurred by Rollins in respect of that distribution and
the proportion of the same to be borne by the relevant Laidlaw Parties, together
with a brief explanation as to the reasons why the expenses so charged to the
Laidlaw Parties would not have been incurred by Rollins in the absence of the
participation by the Laidlaw Parties in that distribution.

     4.4. Dispositions During Registration.  The Laidlaw Parties and their
Affiliates hereby agree that from the date of receipt of written notice (the
"Offering Notice") from Rollins that Rollins intends to file a registration
statement or prospectus (the "Offering Registration Statement") covering shares
of Common Stock or securities convertible into or exercisable for Common Stock
until the Offering Termination Date (defined below), the Laidlaw Parties and
their Affiliates will not sell or otherwise dispose of any securities owned by
such Laidlaw Party or Affiliate except for Registrable Shares included in the
Offering Registration Statement. As used herein, the "Offering Termination Date"
shall occur on (i) the lapse of 60 days from the date of receipt of the Offering
Notice if the Offering Registration Statement is not declared effective (or, if
the Offering Registration Statement is a (final) prospectus to be filed under
any Canadian Securities Act, a receipt is not issued therefor by the applicable
Commissions) before such lapse, (ii) the lapse of 120 days from the date of
effectiveness of the Offering Registration Statement (or, if the Offering
Registration Statement is a (final) prospectus to be filed under any Canadian
Securities Act, the date a receipt has been issued therefor by all applicable
Commissions) if any Registrable Shares are included in the Offering Registration
Statement or (iii) the lapse of 90 days from the date of effectiveness of the
Offering Registration Statement (or, if the Offering Registration Statement is a
(final) prospectus to be filed under any Canadian Securities Act, the date a
receipt has been issued therefor by all applicable Commissions) if no
Registrable Shares are included in the Offering Registration Statement.

     4.5. Transfer of Rights.  The incidental registration and qualification
rights or benefits and mandatory registration and qualification rights or
benefits, including indemnification by Rollins, shall be freely transferable by
the Laidlaw Parties (i) to any Laidlaw Affiliate and (ii) to any Person which
after such transfer would hold at least 10% of the issued and outstanding Common
Stock of Rollins. Upon any transfer of the registration and qualification rights
or benefits of this Registration Agreement, the assigning Laidlaw Party shall
give Rollins written notice prior to or promptly following such transfer stating
the name and address of the transferee and identifying the securities with
respect to which such rights are being assigned. Such notice shall include or be
accompanied by a written undertaking by the transferee to comply with the
obligations imposed hereunder. In the event any registration and qualification
rights or benefits are transferred in accordance with the terms hereof, any
actions required to be taken by the Laidlaw Parties will be taken with the
approval of the holders of such registration and qualification rights or
benefits who hold a majority of the Registrable Securities, whose actions shall
bind all such holders of such registration and qualification rights or benefits.

     4.6. Termination of Registration Rights.  The Laidlaw Parties and their
permitted assigns shall be entitled to exercise any right provided for in this
Registration Agreement until the twelfth anniversary of the date hereof,
provided, however, such rights shall terminate one year from the date 80% of the
Rollins Convertible Debenture has been converted or redeemed.

     4.7. Multijurisdictional Disclosure System.  Nothing in this Registration
Agreement shall be construed to limit or restrict in any manner whatsoever the
ability of Rollins to make use of the Multijurisdictional Disclosure System (as
set forth in National Policy No. 45 of the Canadian Securities Administrators)
with respect to the qualification, distribution or sale in Canada of any
securities of Rollins, including pursuant to request made pursuant to Section
2.1 or Section 2.2 hereof.

                                     A-B-12
<PAGE>

                                   ARTICLE V
                                 MISCELLANEOUS

     5.1. Notices.  All notices or other communications which are required or
may be given under this Registration Agreement shall be in writing and shall be
deemed to have been duly given when delivered in Person or transmitted by
telecopier (with receipt confirmed) to a party at the address or telecopy
number, as applicable, set forth below (as any such address or telecopier number
may be changed from time to time by notice similarly given):

          (i) if to any Laidlaw Party, to:

                 Laidlaw Inc.
                 3221 North Service Road
                 Burlington, Ontario
                 Canada L7R 3YS
                 Attention: Ivan R. Cairns
                 Telecopier No.: (905) 332-6550

          (ii) if to Rollins, to:

                 Rollins Environmental Services, Inc.
                 One Rollins Plaza
                 2200 Concord Pike
                 Wilmington, Delaware 19803
                 Attention: General Counsel
                 Telecopier No.: (302) 426-3555

     5.2. Section Headings.  The article and section headings in this
Registration Agreement are for reference purposes only and shall not affect the
meaning or interpretation of this Registration Agreement. References in this
Registration Agreement to a designated "Article" or "Section" refer to an
Article or Section of this Registration Agreement unless otherwise specifically
indicated.

     5.3. Governing Law.  This Registration Agreement shall be construed and
enforced in accordance with and governed by the laws of State of Delaware
without regard to its conflict of law rules.

     5.4. Amendments.  This Registration Agreement may be amended only by an
instrument in writing executed by all of the Parties.

     5.5. Entire Agreement.  This Registration Agreement constitutes the entire
agreement between the Parties concerning its subject matter.

     5.6. Severability.  The invalidity or unenforceability of any specific
provision of this Registration Agreement shall not invalidate or render
unenforceable any of its other provisions. Any provision of this Registration
Agreement held invalid or unenforceable shall be deemed reformed, if
practicable, to the extent necessary to render it valid and enforceable and to
the extent permitted by law and consistent with the intent of the Parties to
this Registration Agreement.

     5.7. Counterparts.  This Registration Agreement may be executed in multiple
counterparts, all of which together shall constitute the same instrument.

                                     A-B-13
<PAGE>

     IN WITNESS WHEREOF, the Parties have executed this Registration Agreement
as of the date first above written.

                                        ROLLINS ENVIRONMENTAL SERVICES, INC.

                                        By:
                                           ------------------------------------

                                        Name:
                                             ----------------------------------

                                        Title:
                                              ---------------------------------

                                        LAIDLAW INC.

                                        By:
                                           ------------------------------------

                                        Name:
                                             ----------------------------------

                                        Title:
                                              ---------------------------------

                                        LAIDLAW TRANSPORTATION, INC.

                                        By:
                                           ------------------------------------

                                        Name:
                                             ----------------------------------

                                        Title:
                                              ---------------------------------

                                     A-B-14

<EX-4.P
                       INDENTURE DATED AS OF MAY 1, 1993

                                                                    EXHIBIT 4(P)

                     THE INDUSTRIAL DEVELOPMENT BOARD OF THE
                      METROPOLITAN GOVERNMENT OF NASHVILLE
                               AND DAVIDSON COUNTY

                   (A TENNESSEE PUBLIC NONPROFIT CORPORATION)

                                       TO

                         NATIONSBANK OF TENNESSEE, N.A.
                        (A NATIONAL BANKING ASSOCIATION)

                              NASHVILLE, TENNESSEE

                                     TRUSTEE

                        INDENTURE DATED AS OF MAY 1, 1993

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

                 RELATING TO THE INDUSTRIAL DEVELOPMENT BOARD OF
                    THE METROPOLITAN GOVERNMENT OF NASHVILLE
                   AND DAVIDSON COUNTY INDUSTRIAL DEVELOPMENT
                     REVENUE REFUNDING AND IMPROVEMENT BONDS
                     (OSCO TREATMENT SYSTEMS, INC. PROJECT)

<PAGE>

                                                    This instrument prepared by:
                                                    Bass, Berry & Sims (CKW)
                                                    First American Center
                                                    Nashville, Tennessee 37238

<PAGE>

                                TABLE OF CONTENTS

ARTICLE NO.                                                                Page
                                                                           ----

                  Form of Series 1993 Bond.....................................2

                  Granting Clauses............................................10

     I   Definitions..........................................................12

    II   Execution, Authentication, Maturity,
                  Form and Registration of Bonds..............................16

   III   The Series 1993 Bonds and Bonds of
                  Other Series................................................19

    IV   Accounts and Investment of Funds.....................................23

     V   Redemption of Bonds..................................................26

    VI   Covenants of the Issuer and Release of Property......................28

   VII   Events of Default; Remedies..........................................35

  VIII   Concerning the Trustee...............................................41

    IX   Evidence of Rights of Bondholders....................................48

     X   Supplemental Indenture...............................................49

    XI   Defeasance; Unclaimed Moneys.........................................52

   XII   Miscellaneous Provisions.............................................53

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

This table of contents is provided for purposes of convenience only and does not
constitute a part of the Indenture.

                                        i
<PAGE>

         THIS INDENTURE, made and entered into as of the 1st day of May, 1993,
by and between THE INDUSTRIAL DEVELOPMENT BOARD OF THE METROPOLITAN GOVERNMENT
OF NASHVILLE AND DAVIDSON COUNTY, a public nonprofit corporation organized and
existing under and by virtue of the laws of the State of Tennessee (hereinafter
called the "Issuer"), party of the first part, and NATIONSBANK OF TENNESSEE,
N.A., a national banking association duly qualified to accept and administer the
trusts hereby created (hereinafter called the "Trustee"), and having its
principal place of business in Nashville, Tennessee, party of the second part,
as Trustee;

                              W I T N E S S E T H:

         WHEREAS, the Issuer is a public nonprofit corporation and a public
instrumentality of The Metropolitan Government of Nashville and Davidson County,
Tennessee, and is authorized under Sections 7-53-101 to 7-53-311, inclusive, of
Tennessee Code Annotated, as amended (hereinafter called the "Act") to enter
into loan agreements with manufacturing, industrial, commercial and financial
enterprises with respect to one or more projects for such payments and upon such
terms and conditions as the board of directors of the Issuer may deem advisable
in accordance with the provisions of the Act in order to facilitate the disposal
of solid waste; and

         WHEREAS, the Issuer has heretofore issued its Industrial Development
Revenue Bonds, Series 1989 (OSCO Treatment Systems, Inc. Project) (the "1989
Bonds") pursuant to the Act and pursuant to an Indenture of Trust dated as of
December 1, 1989, as amended by a First Supplemental Indenture of Trust dated as
of January 1, 1991 (the "Prior Indenture") between the Issuer and NationsBank of
Tennessee, N.A. (formerly, Sovran Bank/Central South) (the "Prior Trustee") to
pay a portion of the costs of acquiring and constructing a hazardous waste
disposal facility in Nashville, Tennessee; and

         WHEREAS, the Issuer loaned the proceeds of the sale of the 1989 Bonds
to OSCO Treatment Systems, Inc., a Tennessee corporation (the "Company"),
pursuant to a Loan Agreement dated as of December 1, 1989, as amended by a First
Amendment to Loan Agreement dated as of January 1, 1991 (the "Prior Loan
Agreement"); and

         WHEREAS, the Issuer has heretofore issued its Industrial Development
Revenue Bonds, Series 1991 (OSCO Treatment Systems, Inc. Project) (the "1991
Bonds") pursuant to the authority of the Act and pursuant to the Prior
Indenture, to defray the costs of certain improvements to the project financed
with the 1989 Bonds; and

         WHEREAS,  the Issuer loaned the proceeds of the sale of the 1991 Bonds
to the  Company  pursuant to the Prior Loan Agreement; and

         WHEREAS, the Issuer is authorized and empowered by the provisions of
the Act to issue refunding bonds for the purpose of refunding the 1989 Bonds and
the 1991 Bonds and to secure such refunding bonds as provided in the Act; and

                                        1
<PAGE>

         WHEREAS,  there are currently  outstanding  $6,630,000  principal
amount of the 1989 Bonds and $1,330,000 principal amount of the 1991 Bonds; and

         WHEREAS, the Company has requested that the Issuer issue bonds in the
aggregate principal amount of $15,700,000 and loan the proceeds of the sale
thereof to the Company to (i) prepay its obligations under the Prior Loan
Agreement and thereby refund the outstanding 1989 Bonds and 1991 Bonds, and (ii)
finance the construction, acquisition and installation of modifications and
improvements to the facilities financed by the 1989 Bonds and the 1991 Bonds;
and

         WHEREAS, the Issuer by due action has authorized the issuance under the
Act of $15,700,000 of its Industrial Development Revenue Refunding and
Improvement Bonds, Series 1993 (OSCO Treatment Systems, Inc. Project) (the "1993
Bonds") in order to assist the Company through savings to be realized through
the refunding of the 1989 Bonds and the 1991 Bonds with the proceeds of the 1993
Bonds and through financing such improvements; and

         WHEREAS, the Issuer is authorized and empowered by the provisions of
the Act to issue, sell and deliver the 1993 Bonds for the purposes set forth
above and to enter into this Indenture and a Loan Agreement dated as of May 1,
1993, as the same may be amended or supplemented from time to time (the
"Agreement"); and

         WHEREAS, the Series 1993 Bonds shall be substantially in the following
form with necessary or appropriate variations, omissions and insertions, as
permitted or required by this Indenture:

                           (Form of Series 1993 Bond)
                            UNITED STATES OF AMERICA
                               STATE OF TENNESSEE
                       THE INDUSTRIAL DEVELOPMENT BOARD OF
                    THE METROPOLITAN GOVERNMENT OF NASHVILLE
                               AND DAVIDSON COUNTY
          Industrial Development Revenue Refunding and Improvement Bond
                     (OSCO Treatment Systems, Inc. Project)
                                   Series 1993

NO. R-____

         The Industrial Development Board of the Metropolitan Government of
Nashville and Davidson County, a public non-profit corporation created and
existing by virtue of the laws of the State of Tennessee (hereinafter called the
"Issuer"), for value received, hereby promises to pay, but solely from the
source as hereinafter provided, to the Registered Owner, or registered

                                        2
<PAGE>

assigns, on the Maturity Date identified below the Principal Amount identified
below and in like manner to pay interest on said sum from the Interest Payment
Date (defined herein) next preceding the Date of Authentication shown below,
unless such date is an Interest Payment Date, in which event from the Date of
Authentication, or if such date is prior to any Interest Payment Date, from May
1, 1993, at the fixed Rate of Interest per annum (computed on the basis of a 360
day year containing 12 30-day months) set forth below on November 1, 1993 and
semi-annually thereafter on May 1 and November 1 of each year (each an "Interest
Payment Date") until said principal sum is paid, except as the provisions
hereinafter set forth with respect to redemption prior to maturity may become
applicable hereto.

Registered Owner:

Dated Date:  Maturity Date: Principal Amount: Rate of Interest:

May 1, 1993   May 1, 2003

The principal of and redemption premium, if any, on this Bond are payable in
lawful money of the United States of America upon presentation of this Bond at
the principal corporate trust office of NationsBank of Tennessee, N.A.,
Nashville, Tennessee, as Trustee, or its successor in trust (hereinafter
referred to as the "Trustee"), or at such other location as may be specified by
the Trustee. Payment of each installment of interest shall be made to the
Registered Owner hereof who shall appear on the registration books of the Issuer
maintained by the Trustee at the close of business on the 15th day next
preceding the Interest Payment Date and shall be paid by check or draft of the
Trustee to such Registered Owner at the address as it appears on such
registration books or at such other address as may be furnished in writing by
such Registered Owner to the Trustee.

         Reference is hereby made to the additional provisions of this Bond set
forth on the reverse side hereof and such additional provisions shall for all
purposes have the same effect as if set forth on the front side thereof.

         No recourse under or upon any obligation, covenant or agreement
contained in the Indenture, or in any Bond thereby secured, or under any
judgment obtained against the Issuer or by the enforcement of any assessment or
by any legal or equitable proceeding by virtue of any constitution or statute or
otherwise or under any circumstances, under or independent of the Indenture,
shall be had against any incorporator, member, director or officer, as such,
past, present or future, of the Issuer, either directly or through the Issuer,
or otherwise, for the payment for or to the Issuer or any receiver thereof, or
for or to the holder of any Bond issued thereunder or otherwise, of any sum that
may be due and unpaid by the Issuer upon any such Bond. Any and all personal
liability of every nature, whether at common law or in equity, or by statute or
by constitution or otherwise, of any such incorporator, member, director or
officer, as such, to respond by reason of any act or omission on his part or
otherwise for the payment for or to the

                                        3
<PAGE>

Issuer or any receiver thereof, or for or to the holder of any Bond issued
thereunder or otherwise, of any sum that may remain due and unpaid upon the
Bonds thereby secured or any of them, is hereby expressly waived and released as
a condition of and consideration for the execution of the Indenture and the
issue of the Series 1993 Bonds.

         The law pursuant to which this Bond is issued requires that the
following statement appear on the face hereof:

         Neither this Bond nor the interest hereon shall be taxed by the State
         of Tennessee or any county or municipality thereof.

However, such interest may be subject to the Tennessee corporate excise tax and
a Tennessee privilege tax imposed on savings and loan associations, and the Bond
may be subject to the Tennessee inheritance, gift and estate taxes.

         This Bond shall not be valid or become obligatory for any purpose or be
entitled to any security or benefit under the Indenture until the certificate of
authentication hereon shall have been duly executed by the Trustee.

         IN WITNESS WHEREOF, The Industrial Development Board of the
Metropolitan Government of Nashville and Davidson County has caused this Bond to
be executed in its name by the facsimile signature of the Chairman and attested
by the facsimile signature of its Secretary, and its corporate seal to be
hereunto affixed or printed hereon.

                                               THE INDUSTRIAL DEVELOPMENT BOARD
                                               OF THE METROPOLITAN GOVERNMENT OF
                                               NASHVILLE AND DAVIDSON COUNTY

                                               By:
                                                  -----------------
                                                           Chairman

ATTEST:

--------------------
           Secretary

         (facsimile seal)

                (Form of Trustee's Certificate of Authentication)

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

Date of Authentication:             NATIONSBANK OF TENNESSEE, N.A.,
                                         as Trustee

                                        4
<PAGE>

_______________________             By:________________________
                                             Authorized Officer

                             (ADDITIONAL PROVISIONS)

         This Bond is one of a duly authorized issue of Bonds of the Issuer
known as "The Industrial Development Board of the Metropolitan Government of
Nashville and Davidson County Industrial Development Revenue Refunding and
Improvement Bonds (OSCO Treatment Systems, Inc. Project) Series 1993" (the
"Series 1993 Bonds") in an aggregate principal amount of Fifteen Million Seven
Hundred Thousand Dollars ($15,700,000). All of the Series 1993 Bonds are issued
under and equally and ratably secured as to principal, premium, if any, and
interest by an Indenture (hereinafter called the "Indenture") dated as of May 1,
1993 executed by the Issuer and the Trustee, to which Indenture and all
indentures supplemental thereto reference is hereby made for description of the
trust estate, the nature and extent of the security, and a statement of the
terms and conditions upon which the Series 1993 Bonds are issued and secured,
the rights of the holders thereof and of the Trustee thereunder, and the
indebtedness which is equally secured. As provided in the Indenture, bonds of
other series ranking equally with Series 1993 Bonds may be issued and such Bonds
may vary in such manner as is provided and permitted in the Indenture. All Bonds
from time to time outstanding under the terms of the Indenture are hereinafter
referred to as the "Bonds".

         This Series 1993 Bond is issued in full compliance with the
Constitution and statutes of the State of Tennessee, including among others
Chapter 53 of Title 7, of Tennessee Code Annotated. Pursuant to law and the
proceedings under which this Bond is issued, this Bond is payable solely out of
revenues and receipts derived from a Loan Agreement between the Issuer and OSCO
Treatment Systems, Inc., a Tennessee corporation (the "Company"), pursuant to
which the Issuer has loaned money to the Company to (i) provide funds to refund
all of the outstanding principal amount of the Issuer's Industrial Development
Revenue Bonds, Series 1989 (OSCO Treatment Systems, Inc. Project) and Industrial
Development Revenue Bonds, Series 1991 (OSCO Treatment Systems, Inc. Project),
the proceeds of which were loaned to the Company to finance the acquisition,
construction, equipping and improvement of the Company's hazardous waste
treatment facility in Nashville, Tennessee, and (ii) provide funds for the
construction, acquisition and installation of modifications and improvements to
the facilities financed by such prior bonds. The obligations of the Company
under the Loan Agreement have been secured by a Deed of Trust and a Security
Agreement pursuant to which the Company has granted a first lien on the project
to be financed and refinanced with the proceeds of the Bonds. The payments to be
made by the Company under said Loan Agreement have been assigned to the Trustee
as security for the Bonds, and such payments are sufficient to pay the principal
of, premium, if any, and interest on the Bonds as the same become due and
payable. Laidlaw Inc., a Canadian corporation, has unconditionally guaranteed to
the Trustee for the benefit of the holders

                                        5
<PAGE>

of the Series 1993 Bonds the full and prompt payment of principal of, premium,
if any, and interest on the Series 1993 Bonds pursuant to the Guaranty Agreement
between them dated May 1, 1993. The Metropolitan Government of Nashville and
Davidson County, Tennessee shall in no event be liable for the payment of
principal of, premium, if any, or interest on the Bonds or for the performance
of any pledge, mortgage, obligations or agreement of any kind whatsoever of the
Issuer and none of the Bonds nor any of the Issuer's agreements or obligations
shall be construed to constitute an indebtedness of The Metropolitan Government
of Nashville and Davidson County, Tennessee, within the meaning of any
constitutional or statutory provisions whatsoever.

         As provided in, and to the extent permitted by, Section 10.02 of the
Indenture or any indenture supplemental thereto, the rights and obligations of
the Issuer and of the holders of the Bonds may be modified by the Issuer with
the written consent of the holders of 66-2/3% in aggregate principal amount of
the Bonds then outstanding; provided, however, that no such modification shall
effect the reduction of or the extension of the stated time of payment of, the
principal hereof or of the interest of or premium, if any, hereon or permit the
creation of any lien on the trust estate prior to or on a parity with the lien
of said Indenture (except for additional parity Bonds to the extent permitted by
the Indenture) or deprive the holder hereof of the lien created by said
Indenture on the trust estate without the consent of the holder hereof.

         The Series 1993 Bonds are not subject to redemption prior to maturity
except as hereinafter provided.

         As set forth in Section 5.04 of the Indenture, the Series 1993 Bonds
are subject to redemption as a whole, at any time, at a redemption price equal
to the principal amount thereof, without premium, plus accrued interest to the
redemption date, if one or more of the following events shall have occurred:

                  (a) the Project (as defined in the Indenture) shall have been
         damaged or destroyed to such an extent either (i) as to render the
         Project unsatisfactory to the Company for the purposes for which the
         same was used immediately prior to such damage or destruction, or (ii)
         that the Company deems it unwise to rebuild, repair and restore the
         Project (to be determined in the sole judgment of the Company) or (iii)
         that the restoration costs would exceed the proceeds of insurance;

                  (b) title to, or the temporary use or control of, the whole or
         substantially all of the Project shall have been taken by the exercise
         of the power of eminent domain or condemnation or if such use or
         control of a substantial part of the Project shall be so taken as
         results in rendering the Project unsatisfactory to the Company for the
         purpose for which same was used immediately prior to such taking or
         condemnation (to be determined in the sole judgment of the Company); or

                  (c) the result of any condition of Force Majeure (as defined
         in the Indenture) is in the sole judgment of the Company to cause the
         Project to operate at substantially

                                        6
<PAGE>

         less than the capacity for which it was designed.

         As set forth in Section 5.04 of the Indenture, the Series 1993 Bonds
are subject to redemption as a whole or in part (less than all of such Bonds to
be selected by lot in such manner as may be designated by the Trustee) at any
time at a redemption price equal to the principal amount thereof, without
premium, plus accrued interest to the redemption date, if one or more of the
following events shall have occurred:

                  (a) any  condemnation  proceeds are received by the Trustee
         which are not applied to the restoration or rebuilding of the Project;
         or

                  (b) any title insurance proceeds are received by the Trustee
         which are not applied to remedy the defect in the title of the property
         for which such payment is made.

         As provided in Section 5.05 of the Indenture, the Series 1993 Bonds are
subject to mandatory redemption as a whole, and not in part, on the sixtieth
(60th) day following a "Determination of Taxability" as defined in the
Indenture, at a redemption price equal to 100% of the principal amount of the
Series 1993 Bonds, without redemption premium, to be redeemed and accrued
interest thereon to the date fixed for redemption.

         As provided in Section 5.07 of the Indenture, notice of redemption
(unless waived by the registered owner) shall be given by first class mail
postage prepaid not less than 30 nor more than 60 days before the redemption
date, to the registered owner of any Bond to be redeemed. Any notice of
redemption which is mailed in the manner herein provided shall be conclusively
presumed to have been duly given whether or not the owner receives the notice.
Failure to give notice by mail or any defect in the notice to the owner of any
Bond designated for redemption shall not affect the validity of the proceedings
for redemption.

         As provided in Section 2.06 of the Indenture, this Bond is transferable
by the Registered Owner hereof in person or by his attorney duly authorized in
writing at the main corporate trust office of the Trustee in Nashville,
Tennessee, 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 Series 1993 Bond or Bonds,
of authorized denomination or denominations, for the same aggregate principal
amount, will be issued to the transferee in exchange therefor.

         As provided in Section 2.06 of the Indenture, the Issuer and the
Trustee may deem and treat the Registered Owner hereof as the absolute owner
hereof for the purpose of receiving payment of or on account of principal
hereof, premium, if any, and interest due hereon and for all other purposes and
neither the Issuer nor the Trustee nor any paying agent shall be affected by any
notice to the contrary.

         As provided in Section 3.01 of the Indenture, the Series 1993 Bonds are
issuable as fully registered Bonds in the denominations of $5,000 and any
integral multiple thereof.

                                        7
<PAGE>

         The principal hereof may be declared or may become due on the
conditions and in the manner and at the time set forth in Article VII of the
Indenture upon the occurrence of an event of default as in the Indenture
provided. As provided in Section 7.05 of the Indenture, no Bondholder shall have
any right to bring any action or otherwise to enforce any provision of the
Indenture unless the holders of 25% in aggregate principal amount of the Bonds
then outstanding shall have in writing requested the Trustee to take such action
and have offered the Trustee such reasonable indemnity as it may require against
expenses and liabilities to be incurred, and the Trustee shall have neglected
for 60 days to take such action; provided, however, that the right of any holder
of any Bond to receive payment of the principal thereof and/or interest thereon
when due or to institute suit for the enforcement of any such payment shall not
be impaired or affected without the consent of such holder.

                                   ASSIGNMENT

         FOR VALUE RECEIVED, ______________________________________ hereby sell,
  assign, and transfer unto ____________________________________the within Bond,
together with accrued interest thereon, and all right, title and interest
thereto, and hereby irrevocably authorize and appoint __________________________
Attorney, to transfer said Bond on the books of the within-named Issuer with
full power of substitution in the premises.

         Dated: ______________________, ________.

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

                                             NOTICE: The signature to this
                                             assignment must correspond with
                                             the name as it appears upon the
                                             face of the within Bond in every
                                             particular, without alteration or
                                             enlargement or any change whatever.

Signature guaranteed:
                     ------------------------

Notice: Signatures must be guaranteed by an institution which is a Participant
in the Securities

                                        8
<PAGE>

Transfer Agent Medallion Program ("STAMP")or similar program.

                               (End of Bond Form)

         WHEREAS, all things necessary to make the Series 1993 Bonds, when
authenticated by the Trustee and issued, as in this Indenture provided, valid,
binding and legal special obligations of the Issuer, and to constitute this
Indenture a valid and binding agreement securing the payment of the principal
of, redemption premium, if any, and interest on all Bonds issued and to be
issued hereunder, have been done and performed and the creation, execution and
delivery of this Indenture and the creation, execution and issuance of said
Bonds, subject to the terms hereof, have in all respects been authorized;

                                        9
<PAGE>

         NOW, THEREFORE, THIS INDENTURE FURTHER WITNESSETH:

         That The Industrial Development Board of The Metropolitan Government of
Nashville and Davidson County, party of the first part, in consideration of the
premises and of the acceptance by the Trustee of the trusts hereby created, and
of the purchase and acceptance of the Bonds by the holders thereof, and of the
sum of One Dollar ($1.00) of lawful money of the United States of America to it
duly paid by the Trustee at or before the execution and delivery of these
presents, and for other good and valuable consideration, the receipt whereof is
hereby acknowledged, and in order to secure the payment of the principal of,
premium, if any, and interest on all Bonds at any time issued and outstanding
under this Indenture according to their tenor and effect and the performance and
observance by the Issuer of all the covenants expressed or implied herein and in
the Bonds, has granted, bargained, sold, warranted, alienated, demised,
released, conveyed, assigned, transferred, mortgaged, pledged, set over and
confirmed, and does by these presents hereby grant, bargain, sell, warrant,
alienate, demise, release, convey, assign, transfer, mortgage, pledge, set over
and confirm, unto the Trustee and to its successors in the trusts hereby
created, and to it and its assigns, forever, all of the Issuer's estate, right,
title and interest in, to and under the following described property, rights and
interests (herein sometimes referred to as the "mortgaged property" or "Trust
Estate"), to wit:

                                   DIVISION I

         All right, title and interest of the Issuer in and to the Agreement
(except for the Issuer's right to expenses under Section 4.03 of the Agreement),
it being the intent and purpose hereof that the assignment and transfer to the
Trustee of the payments and other sums due and to become due under the Agreement
shall be effective and operative immediately and shall continue in force and
effect, and the Trustee shall have the right to collect and receive said
payments and other sums for application in accordance with the provisions
hereof, at all times during the period from and after the date of this Indenture
until the indebtedness hereby secured shall have been fully paid and discharged,
including without limitation at all times after the institution and during the
pendency of foreclosure proceedings and after any sale on foreclosure. The
Issuer, however, is to remain liable to observe and perform all the conditions
and covenants in said Agreement provided to be observed and performed by it.

                                   DIVISION II

         The Deed of Trust (which is of record in Book ____, page ___,
Register's Office of Davidson County, Tennessee), the Security Agreement, and
all right, title and interest of the Issuer in and to the property from time to
time subject to the Deed of Trust and the Security Agreement.

                                       10
<PAGE>

                                  DIVISION III

         All moneys and securities held by the Trustee in any of the funds or
accounts established under this Indenture.

                                   DIVISION IV

         All property which is by the express provisions of this Indenture
required to be subject to the lien hereof and any additional property that may,
from time to time hereafter, by delivery or by writing of any kind, be subjected
to the lien hereof, by the Issuer or by anyone on its behalf, and the Trustee is
hereby authorized to receive the same at any time as additional security
hereunder.

         TO HAVE AND TO HOLD, all and singular, the trust estate, including all
additional property which by the terms hereof has or may become subject to the
encumbrance of this Indenture, unto the Trustee and its successors and assigns,
forever.

         IN TRUST, NEVERTHELESS, with power of sale, for the equal and
proportionate benefit and security of the holders from time to time of the Bonds
authenticated and delivered hereunder and issued by the Issuer and outstanding,
without preference, priority or distinction as to lien or otherwise of any one
of said Bonds over any other or others of said Bonds to the end that each holder
of such Bonds has the same rights, privileges and lien under and by virtue of
this Indenture; and conditioned, however, that if the Issuer shall well and
truly pay or cause to be paid fully and promptly when due all indebtedness,
liabilities, obligations and sums at any time secured hereby, including interest
and reasonable attorney's fees, and shall promptly, faithfully and strictly
keep, perform and observe or cause to be kept, performed and observed all of its
covenants, warranties and agreements contained herein, then and in such event
this Indenture shall be and become void and of no further force and effect,
otherwise the same shall remain in full force and effect, and upon the trust and
subject to the covenants and conditions hereinafter set forth.

                                    ARTICLE I

                                   Definitions

         Section 1.01. In addition to words and terms elsewhere defined in this
Indenture, the following words and terms as used in this Indenture and in the
Bonds shall have the following meanings, unless some other meaning is plainly
intended:

         "Act" means the  provisions of Chapter 53 of Title 7 of Tennessee Code
Annotated,  as may be amended from time to time.

                                       11
<PAGE>

         "Agreement" means the Loan Agreement of even date herewith between the
Issuer and the Company, as may be amended from time to time.

         "Authorized Company Representative" means the person at the time
designated to act on behalf of the Company pursuant to Section 2.09 of the
Agreement.

         "Authorized Newspaper" means a newspaper of general circulation in
Nashville, Tennessee, printed in the English language, customarily published on
each business day whether or not published on Saturdays, Sundays or holidays.

         "Bond Fund" means the account established under Section 4.01 hereof.

         "Bondholder" and "holder" shall mean the registered owner of a Bond.

         "Bonds" means the bonds of all series from time to time authenticated
and delivered under this Indenture.

         "Building" means the Existing Building and the Modifications.

         "Business Day" means a day on which banks in the States of New York and
Tennessee are not required or authorized by law to remain closed and on which
The New York Stock Exchange is not closed.

         "Certified Resolution" with reference to the Issuer means a copy of a
resolution certified by the Secretary of the Issuer to have been duly passed and
adopted by the Board of Directors of the Issuer at a meeting duly called and
convened.

         "Code" shall mean the Internal Revenue Code of 1986, as amended, and
the regulations issued thereunder.

         "Company" shall mean OSCO Treatment Systems, Inc., a Tennessee
corporation.

         "Construction Fund" means the account established under Section 4.04
hereof.

         The word "continuing" as applied to an event of default, means any
event of default not cured or waived.

         "Deed of Trust" shall mean that certain Deed of Trust of even date
herewith from the Company to Charles K. Wray, as trustee thereunder, securing
the obligations of the Company under the Agreement.

         "Determination of Taxability" means the issuance of a statutory notice
of deficiency by

                                       12
<PAGE>

the Internal Revenue Service which holds in effect that the interest payable on
any of the Series 1993 Bonds is includable in the gross income of a holder
thereof (other than a holder who is a "substantial user" of the Project or a
"related person" within the meaning of such terms as used in Section 147 of the
Code) for federal income tax purposes. Such a Determination of Taxability shall
be deemed to have occurred on the date borne by said statutory notice of
deficiency.

         "Equipment" means all items of machinery, equipment, furniture and
similar property now or hereafter located on or used in connection with the
Building or elsewhere on the Land.

         "Events of Default" is defined in Section 7.01 hereof.

         "Existing Building" shall mean the building, and all other improvements
not constituting part of the Existing Equipment, which have been constructed on
the Land.

         "Existing Equipment" means those items of machinery, equipment and
related property heretofore acquired and installed in the Existing Building or
elsewhere on the Land.

         "Existing Project" means the Land, the Existing Building and the
Existing Equipment.

         "Fiscal Year" shall mean the period commencing on the first day of May
of any year and ending on the last day of April of the next succeeding year.

         "Force Majeure" means without limitation acts of God, strikes, lockouts
or other industrial disturbances, acts of public enemies, insurrections, labor
violence, riots, epidemics, landslides, lightning, earthquakes, fires,
hurricanes, tornadoes, storms, floods, washouts, droughts, arrests, restraints
of government and people, civil disturbances, explosions, breakage, or accidents
to machinery, transmission pipes or canals, delays in delivery of materials,
machines or component parts thereof or equipment, partial or entire failure of
utilities, commercial frustration or any other cause or event not reasonably
within the control of or foreseeable by the party obliged to perform.

         "Government Obligations" shall mean any obligation to the timely
payment of which the full faith and credit of the United States of America are
pledged.

         "Guarantor" means Laidlaw Inc., a Canadian corporation.

         "Guaranty Agreement" means that certain Guaranty Agreement of even date
herewith from the Guarantor to the Trustee.

         "Indenture" shall mean this instrument as originally executed or as it
may from time to time be supplemented or amended by one or more indentures
supplemental hereto.

         "Installment Payments" means the payments set forth in Section 3.01 of
the Agreement.

                                       13
<PAGE>

         "Interest Payment Date" means each May 1 and November 1, commencing
November 1, 1993.

         "Issuer" shall mean The Industrial Development Board of the
Metropolitan Government of Nashville and Davidson County, a Tennessee public
nonprofit corporation.

         "Land" shall mean the real property in Davidson County, Tennessee
conveyed to the Company by deed of record in Book 8007, page 216, Register's
Office of Davidson County, Tennessee.

         "Modifications" means the modifications to the Existing Building to be
made in accordance with Section 2.05 of the Agreement.

         "New Equipment" means those items of machinery, equipment and related
property required by the Agreement to be acquired and installed in the Building
or elsewhere on the Land from the proceeds of the sale of the Series 1993 Bonds.

         "New Project" means the Modifications and the New Equipment.

         "Officers' Certificate" with reference to the Company shall mean a
certificate signed by the President, a Vice President or the Secretary of the
Company, and with reference to the Issuer shall mean a certificate in writing
signed by the Chairman or the Vice Chairman and by the Secretary or the
Assistant Secretary of the Issuer.

         "Opinion of Counsel" means a written opinion of counsel who may, but
need not, be counsel for the Issuer or counsel for the Company.

         "Outstanding" or "outstanding", when used with reference to Bonds,
shall, subject to the provisions of Section 9.04, mean as of any particular time
all the Bonds authenticated and delivered by the Trustee under this Indenture,
except:

                  (a) Bonds  theretofore  cancelled by the Trustee or  delivered
         to the Trustee  cancelled or for cancellation;

                  (b) Bonds for the payment or redemption of which moneys or
         Government Obligations in the necessary amount shall have been
         deposited in trust with the Trustee, provided that if such Bonds are to
         be redeemed prior to the maturity thereof notice of such redemption
         shall have been given as provided in Section 5.07 or provisions
         satisfactory to the Trustee shall have been made for giving such
         notice; and

                  (c) Bonds in substitution for which other Bonds shall have
         been authenticated and delivered pursuant to the terms of Section 2.05
         or 2.06.

                                       14
<PAGE>

         "Permitted Encumbrances" shall have the meaning ascribed to it in
Section 5.01 of the Agreement.

         "Project" shall mean the Building, the Equipment and the Land.

         "Responsible Officers" of the Trustee or any separate trustee or
co-trustee hereunder shall mean the chairman of the board of directors, the
president, every vice president, every assistant vice president, the cashier,
every assistant cashier, the secretary, every trust officer, and every officer
and assistant officer of such Trustee, other than those specifically above
mentioned, to whom any corporate trust matter is referred because of his
knowledge of, and familiarity with, a particular subject.

         "Security Agreement" shall mean that certain Security Agreement of even
date herewith between the Company and the Issuer, securing the obligations of
the Company under the Agreement.

         "Series 1993 Bonds" shall mean the $15,700,000 principal amount of
Industrial Development Revenue Refunding and Improvement Bonds (OSCO Treatment
Systems, Inc. Project) Series 1993 of the Issuer from time to time outstanding
under this Indenture.

         "Trust Estate", "trust estate" or "mortgaged property" shall mean the
property of the Issuer which is subject to the lien of this Indenture or
intended to be subject to the lien of this Indenture.

         "Trustee" shall mean NationsBank of Tennessee, N.A., a national banking
association with its principal offices in Nashville, Tennessee, the party of the
second part of this Indenture and its successors in interest.

         "Underwriter" means J. C. Bradford & Co., a Tennessee partnership.

         "Written Request" with reference to the Issuer shall mean a request in
writing signed by the Chairman, the Vice Chairman or the Secretary of the Issuer
and with reference to the Company, shall mean a request in writing signed by the
President, a Vice President, the Secretary or an Assistant Secretary of the
Company.

         Section 1.02. Words of the masculine gender shall be deemed and
construed to include correlative words of the feminine and neuter gender. The
words "Bond", "holder", and "person" shall include the plural as well as the
singular number unless the context shall otherwise indicate. The word "person"
shall include corporations, associations, natural persons and public bodies
unless the context shall otherwise indicate.

         Any certificate or opinion made or given by an officer of the Issuer,
the Company or any Guarantor may be based, insofar as it relates to legal
matters, upon a certificate or opinion of or

                                       15
<PAGE>

representations by counsel, unless such officer knows that the certificate or
opinion or representations with respect to the matters upon which his
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
certificate or opinion made or given by counsel may be based (insofar as it
relates to factual matters, information with respect to which is in the
possession of the Issuer, the Company or the Guarantor), upon the certificate or
opinion of or representations by an officer or officers or officials of the
Issuer, the Company or the Guarantor, unless such counsel knows that the
certificate or opinion or representations with respect to the matters upon which
his 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.

                                   ARTICLE II

                      Execution, Authentication, Maturity,
                         Form and Registration of Bonds

         Section 2.01. The Bonds authorized to be issued under this Indenture
shall be designated as "The Industrial Development Board of the Metropolitan
Government of Nashville and Davidson County Industrial Development Revenue
Refunding and Improvement Bonds (OSCO Treatment Systems, Inc. Project)". All
Bonds issued under this Indenture shall be payable solely from the Trust Estate,
including the revenues and receipts derived from the Agreement. The principal
of, premium, if any, and interest on the Bonds issued hereunder are secured by
an assignment of the revenues and receipts from the Trust Estate out of which
the same are payable and are further secured by the lien of this Indenture on
the Trust Estate.

         Section 2.02. The principal of, premium, if any, and the interest on
the Bonds shall be payable in any coin or currency of the United States of
America which on the respective dates of payment thereof is legal tender for the
payment of public and private debts. The principal of and premium, if any, on
all Bonds shall be payable at the office of the Trustee, and payment of the
interest on each Bond shall be made by the Trustee on each interest payment date
to the person appearing on the registration books maintained by the Trustee as
the registered owner thereof at the close of business on the 15th day next
preceding the interest payment date by check or draft mailed to such registered
owner at his address as it appears on such registration books or at such other
address as may be furnished in writing by such registered owner to the Trustee.
Payment of the principal of and premium, if any, on the Bonds shall be made upon
the presentation and surrender of such Bonds as the same shall become due and
payable.

         Section 2.03. Only Bonds authenticated by the endorsement thereon of a
certificate substantially in the form hereinbefore recited, executed by the
Trustee, by one of its authorized Responsible Officers, shall be valid or become
obligatory for any purpose or be secured by this Indenture or shall be entitled
to any benefit hereunder; and every certificate of the Trustee upon any Bond
purporting to be secured hereby shall be conclusive evidence that such Bond so

                                       16
<PAGE>

authenticated has been duly authenticated and delivered hereunder, and that the
holder is entitled to the benefit of the trusts hereby created.

         Section 2.04. All Bonds issued and to be issued under this Indenture
shall be executed in the name of the Issuer by the manual or facsimile signature
of its Chairman or Vice Chairman and its corporate seal, or a facsimile thereof,
affixed thereto and attested by the manual or facsimile signature of its
Secretary or Assistant Secretary. In case any of the officers of the Issuer who
shall have signed any Bond shall cease to be such officer before the Bond so
signed shall have been actually authenticated by the Trustee or delivered or
issued, such Bond may be authenticated and delivered and issued with the same
effect as though the person who had signed such Bond had not ceased to be an
officer of the Issuer.

         Section 2.05. Bonds of any series may be initially issued in temporary
form exchangeable for definitive Bonds of the same series when ready for
delivery. The temporary Bonds shall be of such denomination or denominations, as
may be determined by the Issuer, and may contain such reference to any of the
provisions of this Indenture as may be appropriate. Every temporary Bond shall
be executed by the Issuer and be authenticated by the Trustee upon the same
conditions and in substantially the same manner as the definitive Bonds. If the
Issuer issues temporary Bonds, it will execute and furnish definitive Bonds
without delay and thereupon the temporary Bonds may be surrendered for
cancellation in exchange therefor at the office of the Trustee, and the Trustee
shall authenticate and deliver in exchange for such temporary Bonds an equal
aggregate principal amount of definitive Bonds of the same series and maturity
of authorized denominations. Until so exchanged, the temporary Bonds shall be
entitled to the same benefits under this Indenture as definitive Bonds
authenticated and delivered hereunder.

         In case any temporary or definitive Bond issued hereunder shall become
mutilated, or be lost, stolen or destroyed, the Issuer, in its discretion, shall
issue, and the Trustee shall authenticate and deliver, a new Bond of like tenor,
amount, maturity and date, and bearing the same or a different number, in
exchange and substitution for, and upon the cancellation of, the mutilated Bond,
or in lieu of and substitution for such lost, stolen or destroyed Bond, or if
any such Bond shall have matured or shall be about to mature, instead of issuing
a substituted Bond the Issuer may pay or authorize payment of such Bond without
surrender thereof.

         In every case the applicant shall furnish evidence satisfactory to the
Issuer and the Trustee of the destruction, theft or loss of such Bond, and
indemnity satisfactory to the Trustee, which indemnity shall protect the
Trustee, the Issuer and the Guarantor; and the Issuer may charge the applicant
for the issue of such new Bond an amount sufficient to reimburse the Issuer for
the expense incurred by it in the issue thereof.

         Section 2.06. The Trustee shall maintain at its principal corporate
trust office in Nashville, Tennessee a register in which, at the Issuer's
expense (other than transfer taxes, if any) the Trustee shall provide for the
registration and transfer of the Bonds. Whenever any Bond

                                       17
<PAGE>

shall be surrendered at such office for transfer or such other office of the
Trustee as it shall designate, the Issuer at its expense will execute and
deliver in exchange therefor a new Bond or Bonds of the same series and
maturity, of authorized denomination or denominations, for the same aggregate
principal amount as the Bond so surrendered, provided that any transfer tax
relating to such transaction shall be paid by the holder requesting such
transfer. The Trustee shall not be required to transfer any Bond during the
period of fifteen (15) days next preceding any interest payment date of such
Bond or, in the case of any proposed redemption of Bonds, during the fifteen
(15) days immediately preceding the selection of Bonds for such redemption or
after such Bonds or any portion thereof have been selected for redemption. The
Issuer and the Trustee may treat the person in whose name any Bond is registered
as the owner of such Bond for the purpose of receiving payment of the principal
of, premium, if any, and interest on such Bond and for all other purposes,
whether or not such Bond be overdue, and neither the Issuer nor the Trustee
shall be affected by any notice to the contrary.

                                   ARTICLE III

                 The Series 1993 Bonds and Bonds of Other Series

         Section 3.01. The first series of Bonds authorized to be issued
hereunder shall be entitled "The Industrial Development Board of the
Metropolitan Government of Nashville and Davidson County Industrial Development
Revenue Refunding and Improvement Bonds (OSCO Treatment Systems, Inc. Project)
Series 1993" and shall be in the aggregate principal amount of Fifteen Million
Seven Hundred Thousand Dollars ($15,700,000). The Series 1993 Bonds shall be
issuable as fully registered bonds in the denomination of $5,000 and any
integral multiple thereof. The Series 1993 Bonds shall be numbered from R-1
upward.

         Interest on each Series 1993 Bond shall be payable from the Interest
Payment Date next preceding the date on which it is authenticated unless such
date is an Interest Payment Date, in which event from the date on which it is
authenticated, or if such date is prior to any Interest Payment Date, from May
1, 1993. Interest on the Series 1993 Bonds shall be payable on May 1 and
November 1 of each year commencing November 1, 1993.

         The Series 1993 Bonds and the Trustee's Certificate of Authentication
shall be substantially in the form and be of the tenor and purport, respectively
hereinbefore set forth.

         The Series 1993 Bonds shall bear annual interest (computed on the basis
of a 360-day year consisting of 12 30-day months) at a rate of 6.00% and shall
mature on May 1, 2003.

         Section 3.02. The Trustee, forthwith upon the execution and delivery of
this Indenture or from time to time thereafter upon the execution and delivery
to it by the Issuer of the Series 1993 Bonds and without any further action on
the part of the Issuer, shall authenticate Series 1993 Bonds in the aggregate
principal amount of not to exceed Fifteen Million Seven Hundred

                                       18
<PAGE>

Thousand Dollars ($15,700,000) and shall deliver them to or upon the Written
Request of the Issuer.

         The Issuer shall simultaneously deposit with the Trustee all of the
proceeds from the sale of the Series 1993 Bonds (including accrued interest on
the Series 1993 Bonds from their date to the date of their delivery to the
purchasers) as set forth in the Written Request of the Issuer and the Trustee
shall out of such proceeds:

                  (a) Deposit to the credit of the Bond Fund the accrued
         interest on the Series 1993 Bonds from their date to the date of their
         delivery. It is understood that the amount so deposited shall
         constitute a credit to the Company on the then next succeeding payment
         or payments of Installment Payments due or to become due under the
         Agreement.

                  (b) Deposit with the Prior Trustee, to the credit of the
         General Account of the Bond Fund created under the Prior Indenture, the
         sum of $7,960,000.

                  (c) Deposit the remainder of such proceeds to the credit of
         the Construction Fund.

         Section 3.03. Subject to the provisions of this Article III, Bonds of
any series other than Series 1993 Bonds shall contain such variant provisions,
if any, as to date, maturity or serial maturities, interest rate (or interest
rates in the case of serial maturities) and redemption, and shall be entitled to
such sinking fund provisions and shall be limited to such aggregate principal
amount, if any, as shall be determined by the Board of Directors of the Issuer
and set forth in an indenture supplemental hereto at the time any such other
series is created.

         Section 3.04. Bonds of series other than Series 1993 Bonds may be fully
registered bonds, shall be of such denomination or denominations and shall be in
such form or forms, not substantially different from the form of Series 1993
Bonds, except as may be occasioned by variant provisions applicable to such
series. Bonds of any series may be endorsed with such notations or legends as
may be required by any indenture supplemental hereto, or as may be required to
conform to usage or law and be approved by the Trustee.

         Section 3.05. Subject to the provisions of Section 3.06 hereof, one or
more series of Bonds in addition to the Series 1993 Bonds may be authenticated
and delivered from time to time when authorized by resolution or resolutions of
the Board of Directors of the Issuer which shall specify:

                  (a)  The authorized principal amount of such series, the
         designation and denomination or denominations thereof and the
         directions for the authentication and delivery of the Bonds upon
         payment of the purchase price therein set forth;

                  (b)  The purpose for which such series is being issued;

                                       19
<PAGE>

                  (c)  The date of such series and maturity dates and amounts
         of the Bonds thereof;

                  (d)  The interest rate or rates of such series and the
         interest payment dates therefor, provided that the interest rate or
         rates shall be identical for all Bonds of a series of a like maturity
         and the interest payment dates shall be identical for all Bonds of a
         series;

                  (e)  The redemption premiums and redemption terms, if any, for
         such Bonds; and

                  (f)  Any other matters deemed appropriate or necessary by the
         Board of Directors of the Issuer and not inconsistent with the
         provisions of this Indenture.

         Section 3.06. So long as no event of default shall be continuing
hereunder, the Issuer may issue additional Bonds under this Indenture pursuant
to the provisions and limitations herein set forth, for any one or more of the
purposes set forth in Section 2.06 of the Agreement; provided, however, that in
no event shall the Issuer issue any additional Bonds hereunder if as a result of
the issuance thereof the interest on the Series 1993 Bonds or the Bonds of
additional series will not be fully excludable from the gross income of the
recipients thereof under the Code. The Bonds of each series other than Series
1993 shall be executed by the Issuer and delivered to the Trustee and thereupon
shall be authenticated by the Trustee and delivered to or upon the Written
Request of the Issuer, but only upon receipt by the Trustee of:

                  (a)  A copy of the resolution or resolutions referred to in
         Section 3.05 hereof and of a resolution or resolutions of the Board of
         Directors of the Issuer authorizing or ratifying the supplemental
         instrument referred to in paragraph (b) of this Section 3.06, certified
         by the Secretary of the Issuer, and a Certified Resolution of the
         Issuer authorizing or ratifying a supplemental indenture authorizing
         the new series and pledging and assigning all rights of the Issuer
         under such supplemental instrument and the additional Installment
         Payments for such series to the Trustee.

                  (b)  An executed counterpart of a supplemental instrument
         executed by the Issuer and the Company pursuant to Section 2.06 of the
         Agreement and Section 10.01 hereof containing a schedule of payments of
         Installment Payments which are not less than the payment of principal,
         premium, if any, and interest, when due, for such series and payments,
         if any, into reserve funds required to be made as a consequence of the
         issuance of such series.

                  (c)  Executed counterpart or counterparts of a supplemental
         instrument or instruments as are necessary to subject to the lien of
         the Deed of Trust and/or the Security Agreement all property paid for
         with the proceeds of the new series of Bonds.

                                       20
<PAGE>

                  (d) An executed counterpart of a supplemental indenture
         setting forth the provisions of the new series and pledging and
         assigning to the Trustee all the right, title and interest of the
         Issuer in and to the supplemental instrument referred to in
         sub-paragraph (b) or (c) of this Section 3.06;

                  (e) An Opinion of Counsel to the effect that (i) such Bonds
         are valid and binding obligations of the Issuer and enforceable in
         accordance with their terms and the terms of this Indenture, subject to
         bankruptcy and insolvency laws; (ii) such Bonds have been duly and
         validly authorized and issued in acordance with law, this Indenture and
         the Agreement; (iii) the Agreement has been effectively supplemented by
         the supplemental instrument referred to in subparagraph (b) of this
         Section 3.06 and the Agreement as supplemented is valid and binding on
         the Issuer and the Company, subject to bankruptcy and insolvency laws;
         and (iv) the Indenture constitutes a valid first lien on the property
         described in the granting clauses thereof, as supplemented and
         amended, and that all rights of the Issuer under the supplemental
         instrument referred to in sub-paragraph (b) or (c) of this Section
         3.06 and all Installment Payments payable under the Agreement as so
         supplemented are effectively assigned to the Trustee for the security
         of the Bonds issued hereunder.

                  (f) An Officers' Certificate of the Issuer stating that no
         Bonds have been theretofore issued on the basis of the supplemental
         instrument referred to in subparagraph (b) of this Section 3.06 and
         that on the date of the authentication and delivery of such Bonds
         neither the Issuer nor the Company is in default in the performance or
         observance of any of the covenants, conditions, agreements or
         provisions of this Indenture, or the Agreement.

                  (g) A copy of the resolution or resolutions of the Board of
         Directors of the Company authorizing or ratifying the supplemental
         instruments referred to in sub-paragraph (b) or (c) of this Section
         3.06, certified by the Secretary or an Assistant Secretary of the
         Company.

                  (h) A certificate of the Company stating that the Company
         approves the issuance of the Bonds of the new series and is not in
         default in the performance or observance of any of the covenants,
         conditions, agreements, or provisions of the Agreement, the Deed of
         Trust or the Security Agreement.

                  (i) The purchase  price of the Bonds being  delivered as
         stated in the  resolution  referred to in Section 3.05 hereof.

                  (j) A Written Request of the Issuer for the authentication and
         delivery of such Bonds.

                  (k) In the case of additional Bonds issued for the purpose of
         redeeming Bonds

                                       21
<PAGE>

         of any series prior to their stated maturity or maturities, such
         additional documents as shall be required by the Trustee to show that
         provision has been duly made in accordance with the terms of this
         Indenture for redemption of all of the Bonds to be refunded.

                  (l) An executed counterpart of a guaranty agreement executed
         by the Guarantor substantially in the form of the Guaranty Agreement,
         guaranteeing the payment of the principal of, redemption premium, if
         any, and interest on the additional series of Bonds.

         The proceeds from the sale of Bonds of such series received by the
Trustee shall be applied by the Trustee in substantially the same manner as
provided in Section 3.02 in regard to the Series 1993 Bonds; provided that in
the case of additional Bonds issued for the purpose of redeeming Bonds of any
series prior to their stated maturity or maturities, an amount which, with any
other funds that shall be available therefor, will be sufficient for paying the
principal and redemption premium, if any, of the Bonds to be refunded and the
interest which shall accrue thereon to the date fixed for their payment or
redemption, shall be deposited to the credit of a special account appropriately
designated, to be held in trust by the Trustee for the sole and exclusive
purpose of paying such principal, redemption premium and interest; and moneys
held for the credit of such special account shall, as nearly as may be
practicable and reasonable, be invested and reinvested by the Trustee in
Government Obligations which shall mature, or which shall be subject to
redemption by the holder thereof at the option of the holder, not later than the
respective dates when the moneys held for the credit of such special account
will be required for the purposes intended.

         Section 3.07. All Bonds of all series from time to time outstanding
under this Indenture shall be equally and ratably secured both as to principal,
premium, if any, and interest by this Indenture.

                                   ARTICLE IV

                        Accounts and Investment of Funds

         Section 4.01. There is hereby created by the Issuer and ordered
established with the Trustee a trust fund to be designated "The Industrial
Development Board of the Metropolitan Government of Nashville and Davidson
County Bond Fund (OSCO Treatment Systems, Inc. Project)" (the "Bond Fund") which
shall be used to pay the principal of, premium, if any, and interest on the
Bonds. The Trustee shall keep and maintain adequate records pertaining to the
Bond Fund and all disbursements therefrom.

         Section 4.02. There shall be deposited into the Bond Fund from the sale
of the Series 1993 Bonds the amount specified in Section 3.02 (a) hereof. In
addition, there shall be deposited into the Bond Fund, as and when received (a)
any amount remaining in the Construction Fund (referred to in the Agreement as
the Surplus Construction Fund Money) to the extent provided in

                                       22
<PAGE>

Section 2.07 of the Agreement; (b) all Installment Payments specified in Section
3.01 of the Agreement; (c) all moneys received by the Trustee under and pursuant
to the Agreement which may be used by the Trustee for the redemption of Bonds;
(d) any payments received under the Guaranty Agreement; and (e) all other moneys
received by the Trustee under and pursuant to any of the provisions of the
Agreement when accompanied by directions by the Company that such moneys are to
be paid into the Bond Fund.

         Section 4.03. Except as provided in Sections 4.09 and 4.10 hereof,
moneys in the Bond Fund shall be used solely for the payment of the principal
of, premium, if any, and interest on the Bonds and for the redemption of the
Bonds prior to maturity. Whenever the amount in the Bond Fund from any source
whatsoever is sufficient to redeem all of the Bonds outstanding hereunder and to
pay any applicable premium and interest to accrue thereon prior to such
redemption, the Issuer shall (if the Company so directs) take and cause to be
taken the necessary steps to redeem all of the Bonds on the next succeeding
redemption date for which the required redemption notice may be given; provided,
however, that any moneys in the Bond Fund may be used to redeem a part of the
Bonds outstanding so long as the Company is not in default with respect to any
Installment Payments and to the extent such moneys are in excess of the amount
required for payment of Bonds theretofore matured or called for redemption and
past due interest (including, without limitation, in all cases where such Bonds
have not been presented for payment).

         Section 4.04. There is hereby created and established with the Trustee
a trust fund in the name of the Issuer to be designated "The Industrial
Development Board of the Metropolitan Government of Nashville and Davidson
County Construction Fund (OSCO Treatment Systems, Inc. Project)" (the
"Construction Fund"). Moneys in the Construction Fund shall be expended in
accordance with the provisions of the Agreement, and particularly Section 2.07
thereof.

         The Trustee is hereby authorized and directed to issue its checks for
each disbursement required by the aforesaid provisions of the Agreement.

         The Trustee shall keep and maintain adequate records pertaining to the
Construction Fund and all disbursements therefrom and after the New Project
shall have been completed and a certificate of payment of all costs filed as
provided in Section 4.05 hereof, the Trustee shall, if requested by the Company,
file an accounting thereof with the Issuer and with the Company.

         Section 4.05. The completion of the New Project and the payment of all
costs and expenses incident thereto shall be evidenced by the filing with the
Trustee of the certificate of the Authorized Company Representative required by
the provisions of Section 2.08 of the Agreement. As soon as practicable and in
any event not more than sixty days from the date of the certificate referred to
in the preceding sentence any balance attributable to the proceeds of the Series
1993 Bonds remaining in the Construction Fund shall be applied in accordance
with instructions from the Company pursuant to Section 2.07 of the Agreement.

         Section 4.06. Reference is hereby made to Articles VIII and IX of the
Agreement whereunder it is provided that under certain circumstances the net
proceeds of insurance and

                                       23
<PAGE>

condemnation awards are to be paid to the Trustee and to be disbursed and paid
out as therein provided. The Trustee hereby accepts and agrees to perform the
duties and obligations as therein specified.

         Section 4.07. A mortgage title insurance policy has been issued
insuring the Trustee for the benefit of the holders of the Bonds. In the event
that payment is made to the Trustee under said policy, such moneys shall be
applied by the Trustee (i) first to remedy the defect in the title of the
property for which such payment is made, and (ii) thereafter, to the extent of
any such moneys remaining after the payments required by clause (i) of this
Section 4.07 shall have been made, to the redemption of Bonds pursuant to
Section 5.04 hereof, and any balance shall be paid to the Company.

         Section 4.08. All moneys received by the Trustee under the provisions
of this Indenture shall be trust funds under the terms hereof and shall not be
subject to lien or attachments of any creditor of the Issuer or the Company.
Such moneys shall be held in trust and applied in accordance with the provisions
of this Indenture.

         Section 4.09. Any moneys held as part of the Construction Fund or Bond
Fund shall, to the extent permitted by law, at the written request of and as
specified by the Authorized Company Representative, be invested and reinvested
by the Trustee in accordance with the provisions of Section 2.10 of the
Agreement. Any such investments shall be held by or under the control of the
Trustee and shall be deemed at all times a part of the Construction Fund or Bond
Fund, as the case may be, and the interest accruing thereon and any profit
realized from such investments shall be credited to such fund, and in the case
of the Bond Fund constitute a credit against the next payment or payments of
Installment Payments due under the Agreement and any loss resulting from such
investments shall be charged to such fund. The Trustee is directed to sell and
reduce to cash funds a sufficient amount of such investments whenever the cash
balance in the Construction Fund or Bond Fund is insufficient to pay a
requisition or payment when due, as the case may be when presented. The Trustee
may make any and all investments permitted under this Section 4.09 through its
own Bond Department or Trust Department.

         Section 4.10. Any amounts remaining in the Bond Fund, the Construction
Fund or any other separate trust account maintained by the Trustee pursuant to
this Indenture or the Agreement, after payment in full of the principal of,
interest and premiums if any, on the Bonds (or provision for payment thereof as
provided in this Indenture), the fees, charges and expenses of the Trustee and
any paying agents and all other amounts required to be paid hereunder, shall be
promptly paid to the Company as a refund of excess Installment Payments.

                                    ARTICLE V

                               Redemption of Bonds

                                       24
<PAGE>

         Section 5.01. Under the terms of Section 4.07(ii) of this Indenture and
Sections 8.02, 8.03, 9.02, 10.04, 14.01 and 14.02 of the Agreement, moneys are
to be paid to the Trustee and the Trustee shall use such moneys for the purpose
of redeeming Bonds when redeemable, except as otherwise herein provided. The
Series 1993 Bonds shall be so redeemable pursuant to the provisions of Section
5.04 and 5.05 hereof and Bonds of other series shall be so redeemable pursuant
to the provisions of Section 5.09 hereof. The Issuer covenants that any and all
such moneys received by it which are to be used to redeem Bonds shall be paid to
the Trustee under this Indenture and, in such event, the Trustee shall use any
and all such moneys to redeem Bonds when and as the Bonds shall in accordance
with their terms be redeemable.

         Section 5.02. If moneys received by the Trustee under and pursuant to
the provisions of Section 5.01 hereof for the purpose of redeeming Bonds are not
sufficient to pay principal of and interest (and premium, if any) on the Bonds
of all series until the next succeeding redemption date on which Bonds of such
series may be redeemed and to redeem all the Bonds of such series on such
redemption date, the Trustee shall, upon receipt, allocate such moneys among the
various series of Bonds outstanding pro rata on the basis of the aggregate
principal amount of the Bonds of each series then outstanding. The Trustee shall
apply such money so allocated to the redemption of Bonds of each such series on
the next succeeding date on which Bonds of such series may be redeemed in
accordance with the terms thereof. Any redemption premium shall be paid out of
such moneys. Any unapplied balance of such moneys so allocated to any series
shall be held by the Trustee and applied to the next redemption of Bonds of such
series hereunder. Notwithstanding the foregoing provisions of this Section 5.02,
the Issuer may redeem all or any part of any series of Bonds pursuant to the
optional redemption provisions of the Indenture applicable thereto without the
Trustee's being required to allocate any moneys to the redemption of any other
series of Bonds.

         Section 5.03.  (Intentionally Omitted).

         Section 5.04. The Series 1993 Bonds are subject to redemption at any
time as a whole, but not in part, through the application of moneys received
pursuant to Sections 8.02, 9.02 and 14.02(b) of the Agreement, and are subject
to redemption at any time in whole or in part (less than all of such Bonds to be
selected by lot in such manner as may be designated by the Trustee) through the
application of moneys received pursuant to Section 4.07(ii) hereof or Section
8.03 of the Agreement, at a redemption price equal to 100% of the principal
amount of the Bonds to be redeemed plus accrued interest thereon to the date of
redemption and without redemption premium.

         Section 5.05. The Trustee is hereby directed to use that portion of
moneys received by it pursuant to Section 14.01 of the Agreement constituting
the prepayment of All Unpaid Installments for the purpose of redeeming Series
1993 Bonds on the sixtieth (60th) day following the Determination of Taxability.
The Series 1993 Bonds shall be subject to mandatory redemption through the
application of such moneys as a whole, and not in part, at a redemption price
equal to 100% of the principal amount of the Series 1993 Bonds to be redeemed
and

                                       25
<PAGE>

accrued interest thereon to the date fixed for redemption and without
redemption premium.

         Section 5.06. If less than all of the Bonds of a particular maturity of
a series shall be called for redemption, the particular portions ($5,000 or any
integral multiple thereof) of Bonds of such maturity to be redeemed shall be
selected by the Trustee by lot or in such other random manner as the Trustee in
its discretion may determine.

         Section 5.07. Notice of redemption (unless waived by the Bondholder)
shall be given by the Trustee by first class mail, postage prepaid, not less
than thirty (30) nor more than sixty (60) days prior to the redemption date, to
the registered owner of each Bond designated for redemption. Each notice of
redemption shall state the redemption date, the place of redemption, and the
principal amount, and, if less than all of any one maturity, the distinctive
numbers and letters of the Bonds to be redeemed and, in the case of Bonds to be
redeemed in part only, the portion of the principal amount thereof to be
redeemed. In case any Bond is to be redeemed in part only, the notice of
redemption which relates to that Bond shall also state that on or after the
redemption date, upon surrender of the Bond, a new Bond will be issued. The
notice of redemption shall also state that the interest on the Bonds, or
portions of Bonds, in such notice 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, or portions of Bonds, the
principal amount thereof to be redeemed, premium, if any, and interest accrued
thereon to the redemption date. Any notice of redemption which is mailed in the
manner herein provided shall be conclusively presumed to have been duly given
whether or not the owner receives the notice. Failure to give notice by mail or
any defect in the notice to the owner of any Bond designated for redemption
shall not affect the validity of the proceedings for redemption.

         Section 5.08. Notice having been given in the manner and under the
conditions hereinabove provided, and moneys for payment of the redemption price
being held by the Trustee as provided in this Indenture (i) the Bonds, or
portions of Bonds, so called for redemption shall, on the redemption date
designated in such notice, become due and payable at the redemption price
provided for redemption of such Bonds, or portions of Bonds, on such date and
interest on the Bonds, or portions of Bonds, so called for redemption shall
cease to accrue, (ii) such Bonds, or portions of Bonds, shall cease to be
entitled to any lien, benefit or security under this Indenture, and (iii) the
holders of said Bonds, or portions of Bonds, shall have no rights in respect
thereof except to receive payment of the redemption price thereof.

         Section 5.09. Bonds of each other series are redeemable in the manner,
at the time or times and at the premiums, if any, specified in the supplemental
indenture relating to such series.

                                   ARTICLE VI

                 Covenants of the Issuer and Release of Property

                                       26
<PAGE>

         Section 6.01. (A) The Issuer agrees to procure and maintain (or cause
the Company to procure and maintain) insurance of the type required to be
procured and maintained by the Company under Article VI of the Agreement.
Insurance of the type required by Section 6.02 of the Agreement shall be payable
to the Trustee or the Company, as the case may be, as provided in Section 6.03
and Article IX of the Agreement.  Any insurance moneys received by the Trustee
pursuant to Article IX of the Agreement shall be held by it as a part of the
Trust Estate and shall be used by it in the manner provided in this Section
6.01.  Certificates from insurers evidencing the existence of all Policies
required by Article VI of the Agreement shall be filed with the Trustee to the
extent required by Section 6.04 of the Agreement.  The Trustee shall review all
such certificates of insurance to verify compliance with the requirements of
Article VI of the Agreement.

         If all or any part of the Project shall be destroyed or damaged and the
Company repairs, rebuilds, replaces, restores or reconstructs the damaged
Project pursuant to the provisions of Section 9.01 of the Agreement, the Trustee
shall, from any insurance proceeds received and held by it on account of such
damage or destruction, from time to time pay the costs of such repair,
rebuilding, replacement, restoration and reconstruction, or reimburse the
Company for payment of such costs, upon receipt of a request therefor
substantially in the form of Exhibit A to the Agreement, modified to reflect a
request for disbursement of insurance proceeds rather than moneys from the
Construction Fund, signed by the Authorized Company Representative. Within 30
days after completion of such repair, rebuilding, replacement, restoration and
reconstruction, the Company shall deliver to the Trustee an Officers'
Certificate of the Company accompanied by an approving certificate of an
engineer or architect employed by the Company stating that the Company has
repaired, rebuilt, replaced, restored or reconstructed the damaged Project in
such manner as to restore the Project, or portion thereof, to at least the
market value thereof prior to such damage or destruction, that such repair,
rebuilding, replacement, restoration and construction has been completed, or a
portion thereof has been completed. Upon receipt of such Officer's Certificate
and approving certificate of an engineer or architect any undisbursed insurance
proceeds received and held by the Trustee on account of such damage of
destruction shall be paid to the Company.

         If a substantial portion of the Project shall be destroyed or damaged
while any Bonds are outstanding and the Company delivers and pays to the Trustee
the certificate and amount required to be delivered and paid by it pursuant to
the provisions of Section 9.02 of the Agreement, the Trustee shall pay and
assign to the Company, in accordance with the provisions of Section 9.02 of the
Agreement, all insurance proceeds received and held by it or receivable by it on
account of such damage or destruction to the Project.

         (B) If the entire Project or any part thereof which is sufficient to
render the remaining portion unsatisfactory for the Company's business purposes
is taken by condemnation or sold under threat of condemnation while any Bonds
remain Outstanding and the Company delivers and pays to the Trustee the
certificate and amount required to be delivered and paid by it pursuant to the
provisions of the Agreement, the Trustee shall pay and assign to the Company in

                                       27
<PAGE>

accordance with the provisions of Section 8.02 of the Agreement any condemnation
award received and held by it or receivable by it on account of such taking.

         (C)      If a portion of the Project which is less than that referred
to in paragraph (B) of this Section 6.01 is taken by condemnation or sold under
threat of condemnation while any Bonds remain outstanding, the Trustee shall be
furnished with the following:

         (1)      an Officers' Certificate of the Company stating that the
                  Company has elected to make the necessary adjustments in the
                  Project suitable for its business purposes, or stating that no
                  adjustments were required, as the case may be; and

         (2)      If the Officer's Certificate of the Company described in
                  (C)(1) above states that the Company has elected to make the
                  necessary adjustments in the Project suitable for its business
                  purposes, within 30 days after completion of such adjustments
                  an Officer's Certificate of the Company stating that such
                  adjustments have been completed.

         Upon receiving such items the Trustee shall, out of any condemnation
award received and held by it on account of such taking:

                  (a) if the Officer's Certificate of the Company states that
         the Company has elected to make the necessary adjustments in the
         Project suitable for its business purposes, from time to time pay the
         cost of such adjustments, or reimburse the Company for payment by it of
         such costs, upon receipt by the Trustee of a request for such payment
         or reimbursement in substantially the form of Exhibit A attached to the
         Loan Agreement, modified to reflect a request for disbursement of
         condemnation proceeds rather than a request for disbursement of moneys
         from the Construction Fund; and

                  (b) apply the balance, if any, to the redemption of Bonds in
         accordance with the provisions of Article V hereof; provided, however,
         that if the amount of such balance exceeds the amount needed to redeem
         all of the outstanding Bonds, any excess shall be paid to the Company
         in accordance with the provisions of Section 4.10 hereof.

         Section 6.02. Reference is made to the provisions of the Agreement,
including without limitation Article X thereof, whereby the Company may withdraw
certain items of Equipment referred to in this Indenture and forming a part of
the Trust Estate upon compliance with terms and conditions of the Agreement. The
Trustee shall at the request of the Company release and confirm that any such
Equipment is no longer subject to the Security Agreement or this Indenture upon
compliance with the applicable provisions of the Agreement.

         Section 6.03. If no Event of Default shall have happened and be
continuing hereunder as provided in Article VII hereof, the Company may at any
time or times grant easements, rights of way or similar encumbrances affecting,
dedicate or execute petitions with respect to, any portion

                                       28
<PAGE>

or portions of the Project free from the lien of the Deed of Trust and this
Indenture but only as provided in and subject to the provisions of Section 14.05
of the Agreement, and the Trustee shall execute and deliver a release of said
portion from the lien of the Deed of Trust and this Indenture upon receipt by
the Trustee of:

              (i) an Opinion of Counsel in form and substance satisfactory to
                  the Trustee, to the effect that the action taken or proposed
                  to be taken by the Company is in conformity with Section 14.05
                  of the Agreement relating to such property;

             (ii) an Officers' Certificate of the Company stating that the
                  dedication of said portion does not adversely affect the
                  market value of the remaining portion thereof, nor the use of
                   such remaining portion in the Company's business; and

            (iii) an undertaking of the Company, in form and substance
                  satisfactory to the Trustee, to the effect that the Company
                  shall remain obligated under the terms of the Agreement to the
                  same extent as if said dedication had not been made and that
                  the Company shall, if made necessary by such dedication,
                  restore and rebuild said property to good condition and
                  repair.

         Section 6.04. The Issuer covenants that so long as the Bonds or any of
them shall be outstanding it will cause an office or agency where the Bonds may
be presented for payment to be maintained in the United States. The Issuer
hereby appoints NationsBank of Tennessee, N.A., Nashville, Tennessee, the office
and agency where the Bonds may be presented for payment.

         Section 6.05. Subject to the provisions of Sections 2.01 and 6.17
hereof the Issuer covenants that it will promptly pay the principal of and
interest on every Bond issued under the provisions of this Indenture at the
place, on the dates and in the manner provided herein and in said Bonds, and any
premium required for the retirement of said Bonds by purchase or redemption
according to the true intent and meaning thereof and on or before each date on
which any principal of or premium, if any, or interest on any of the Bonds
becomes payable, whether at stated maturity thereof, by call for redemption, by
declaration or otherwise the Issuer will irrevocably deposit with the Trustee,
under the trusts hereof, the entire amount necessary to pay all the principal,
premium, if any, and interest payable on such date on all Bonds then
Outstanding.

         Section 6.06. So long as any of the Bonds shall remain Outstanding and
unpaid, the Issuer will not directly or indirectly extend or assent to the
extension of the time for the payment of any claim for interest of or upon any
Bond, and will not directly or indirectly be a party to any arrangement
therefor, either by purchasing or refunding or in any manner keeping alive such
claim for interest, or otherwise; that in case the payment of any such claim for
interest shall be so extended by or with or without the consent of the Issuer,
then anything in this Indenture contained to the contrary notwithstanding, such
claim for interest so extended shall not be entitled, in case of default
hereunder, to any benefit of or from this Indenture, except after the

                                       29
<PAGE>

prior payment in full of the principal of all Bonds issued hereunder and of such
claims for interest as shall not have been so extended.

         Section 6.07. The Issuer covenants that while any Bonds are outstanding
hereunder, moneys received by it from payments under the Agreement will, in
aggregate, produce revenues which will be sufficient to make all payments which
the Trustee is obligated to set aside in the various trust accounts established
under Article IV.

         Section 6.08. The Issuer covenants and agrees and hereby appoints the
Trustee to keep or cause to be kept proper books of record and account in which
complete and correct entries shall be made of all transactions relating to the
receipts, disbursements, allocation and application of the revenues received or
disbursed pursuant to the Indenture and amount thereof forwarded to the Trustee,
and such books shall be available for inspection by the holder of any of the
Bonds at reasonable hours and under reasonable conditions.

         Section 6.09. Within two months after the close of each Fiscal Year,
the Trustee shall prepare a statement for such Fiscal Year of all funds coming
into its possession as Trustee under this Indenture and the application and
allocation thereof. Not more than two months after the close of each Fiscal
Year, the Trustee shall furnish to each holder of any of the Bonds, who may so
request in writing, and to the Company and the Guarantor, a complete financial
statement covering receipts, disbursements, allocation and application of
revenues for such Fiscal Year accruing to the Trust Estate and dates and amount
thereof forwarded to the Trustee for such Fiscal Year. The Trustee, the Company
and the Guarantor shall at all times have access to the books and records of the
Issuer relating to the Bonds and the Project. Also the records of the Trustee
pertaining to the issue shall be available to and open for inspection by any
Bondholder during normal business hours, and the Issuer covenants that it shall
promptly furnish the Trustee such additional information as is deemed necessary
by the Trustee to carry out the provisions of this Indenture and the trusts
created hereby.

         Section 6.10. The Issuer covenants that all charges made by the Trustee
and any paying agent for services rendered and for payment of principal of and
interest on the Bonds (not paid by the Company) will be paid by the Issuer from
revenues of the Trust Estate and will not be required to be paid by the holders
of the Bonds.

         Section 6.11. The Issuer covenants that it is, at the date of the
execution and delivery of this Indenture and will be so long as any Bonds are
Outstanding hereunder, lawfully possessed of the Trust Estate; that the
Agreement, the Deed of Trust and the Security Agreement are at the date of the
execution and delivery of this Indenture the valid and subsisting contracts on
the terms therein set forth; that the Agreement, the Deed of Trust and the
Security Agreement were lawfully made by the Company; that the covenants
contained in the Agreement, the Deed of Trust and the Security Agreement are
valid and binding and that this Indenture is executed in conformity therewith;
that the Issuer has good right, full power and lawful authority to grant,
bargain and assign, and to transfer in trust, convey and pledge the Trust Estate
in the manner and

                                       30
<PAGE>

form herein provided; and that the Issuer forever will warrant and defend the
title to the same to the Trustee against the claims of all persons whomsoever
except for claims arising from presently existing restrictions or encumbrances.

         The Issuer and the Trustee shall without the consent of or notice to
the holders of the Outstanding Bonds consent to any amendment, change or
modification of the Agreement, the Deed of Trust, the Security Agreement and the
Guaranty Agreement as may be required (i) by the provisions of the Agreement and
this Indenture, (ii) in connection with the issuance of additional Bonds as
specified in Article III hereof, (iii) for the purpose of curing any ambiguity
or formal defect or omission, (iv) in connection with the furnishings and
equipment described in the Security Agreement so as more precisely to identify
the same or to delete or substitute or add additional furnishing and equipment
acquired with the proceeds of the Bonds in accordance with the provisions
hereof, or (v) in connection with any other change therein which, in the
judgment of the Trustee, is not to the prejudice of the Trustee or the holders
of the Bonds.

         Except for the amendments, changes or modifications as hereinabove
provided in this Section 6.11, neither the Issuer nor the Trustee shall consent
to any other amendment, change or modification of the Agreement, the Deed of
Trust, the Security Agreement and the Guaranty Agreement without the written
approval or consent of the holders of not less than sixty-six and two-thirds per
cent (66-2/3%) in aggregate principal amount of the Outstanding Bonds; provided,
however, that no such modification shall result in the violation of any terms
and provisions of Section 10.02 hereof.

         Section 6.12. The Issuer covenants that it will comply with all the
terms and provisions of the Agreement, and the Certificate of Incorporation of
the Issuer and that it will not engage in any activities or take any action
which might result in the income of the Issuer becoming taxable to it or any
interest payment on the Bonds becoming taxable to the recipient thereof.

         The Issuer covenants and certifies to and for the benefit of the
holders of the Bonds from time to time Outstanding that so long as any of the
Bonds remain Outstanding, the Issuer shall not direct that moneys on deposit in
any fund or account in connection with the Bonds (whether or not such moneys
were derived from the proceeds of the sale of the Bonds or from any other
sources), be used in a manner which will cause the Bonds to be classified as
"arbitrage bonds" within the meaning of Section 148 of the Code.

         Section 6.13. The Issuer further covenants and agrees as follows:

First:         Promptly to take such actions as may be necessary or proper to
               remedy or cure any defect in or cloud upon the title to the trust
               estate or any part thereof, whether now existing or hereafter
               developing, and to prosecute all such suits, actions and other
               proceedings as may be appropriate for such purposes and to
               indemnify and save the Trustee and every such Bondholder harmless
               from all loss, cost, damage and expenses, including attorneys'
               fees, which they or either of them may incur by

                                       31
<PAGE>

               reason of any such defect, cloud, suit, action or proceedings.

Second:        To maintain its existence as a public non-profit corporation
               organized and existing  under the Act and the laws of the State
               of Tennessee.

         Section 6.14. The Issuer will, at its cost, without expense to the
Trustee or the holders of the Bonds, do, execute, acknowledge and deliver or
cause to be done, executed, acknowledged, and delivered all and every such
further acts, conveyances, mortgages, assignments, transfers and assurances as
the Trustee shall require, for the better assuring, conveying, mortgaging,
assigning and confirming unto the Trustee all and singular the Trust Estate
hereby mortgaged, conveyed or assigned or intended so to be, or which the Issuer
may be or may hereafter become bound to mortgage, convey or assign to the
Trustee, or for carrying out the intention or facilitating the performance of
the terms of this Indenture or the Agreement.

         Section 6.15. The Issuer, forthwith upon the execution and delivery of
this Indenture and thereafter from time to time, will, at the request of the
Trustee, cause this Indenture, and each supplement hereto, and all financing
statements, continuation statements and other instruments required by applicable
law necessary in connection therewith to be filed, registered and recorded and
refiled, reregistered and rerecorded as a lien upon the Trust Estate, in such
manner and in such places as may be required by any present or future law in
order to publish notice of and fully protect the lien hereof, and the title of
the Trustee to, the Trust Estate and in order to entitle the Bonds then
outstanding to the benefits and security of this Indenture, and will cause the
Deed of Trust, and any supplement hereto, to be filed, registered or recorded
and refiled, reregistered or rerecorded in such manner and in such places as may
be required by law in order to publish notice and fully protect the validity
thereof, and from time to time will perform or cause to be performed any other
act as provided by law and will execute or cause to be executed any and all
further instruments which may be necessary for such publication, protection and
entitlement. The Issuer will pay or cause to be paid all filing, registration
and recording taxes and fees incident to such filing, refiling, registration,
reregistration, recording and rerecording and all expenses incidental to the
preparation, execution and acknowledgment of this Indenture, the Agreement, the
Deed of Trust and the Security Agreement and any instrument of further assurance
and any supplements to any of said instruments and all federal or state stamp
taxes and other taxes, duties, imposts, assessments and charges arising out of
or in connection with the execution and delivery of this Indenture, the
Agreement, the Deed of Trust and the Security Agreement, the Bonds, any
instrument of further assurance, and any supplements to any of said instruments.

         Section 6.16. Promptly after any filing, registration or recording or
any refiling, reregistration or rerecording of this Indenture, the Agreement,
the Deed of Trust or the Security Agreement or any filing, registration,
recording, refiling, reregistration or rerecording of any supplement to any of
said instruments, any financing statement or instruments of similar character
relating to any of said instruments or any instrument of further agreement which
is required pursuant to Section 6.15, the Issuer will, at the request of the
Trustee, deliver to the

                                       32
<PAGE>

Trustee an Opinion of Counsel to the effect that such filing, registration,
recording, refiling, reregistration or rerecording has been duly accomplished
and setting forth the particulars thereof.

         Section 6.17. Anything in this Indenture to the contrary
notwithstanding, the performance by the Issuer of all duties and obligations
imposed upon it hereby, the exercise by it of all powers granted to it
hereunder, the carrying out of all covenants, agreements, and promises made by
it hereunder, and the liability of the Issuer for all warranties and other
covenants hereunder, shall be limited solely to the Trust Estate, including
revenues and receipts derived from the Agreement, and the Issuer shall not be
required to effectuate any of its duties, obligations, powers or covenants
hereunder except to the extent of the Trust Estate and such revenues and
receipts.

                                   ARTICLE VII

                           Events of Default; Remedies

         Section 7.01. If one or more of the following events (herein called
"Events of Default" or "events of default") shall happen, that is to say,

                  (a) if default shall be made in the due and punctual payment
         of the principal of, or interest on any Bond when and as the same shall
         become due and payable, whether by declaration or otherwise;

                  (b) if default shall be made by the Issuer in the performance
         or observance of any other of the covenants, agreements or conditions
         on its part in this Indenture or in the Bonds contained, and such
         default shall have continued for a period of sixty (60) days after
         written notice thereof (or in the case of any such default which cannot
         with due diligence be cured within such 60-day period, if the Issuer
         shall fail to proceed promptly to commence curing the same and
         thereafter prosecute the curing of such default with due diligence, it
         being intended in connection with any such default not susceptible of
         being cured with due diligence within the 60 days that the time of the
         Issuer within which to cure the same shall be extended for such period
         as may be necessary to complete the curing of the same with all due
         diligence), specifying such default and requiring the same to be
         remedied, shall have been given to the Issuer by the Trustee, or to the
         Issuer and the Trustee by the holders of not less than twenty five per
         cent (25%) in aggregate principal amount of the Outstanding Bonds;

                  (c) if (i) the Issuer files a petition in bankruptcy or for
         composition under any State or Federal bankruptcy or insolvency law, or
         makes an assignment for the benefit of its creditors or consents to the
         appointment of a receiver for itself or the whole or any part of its
         property, or (ii) a court of competent jurisdiction shall enter an
         order, judgment or decree appointing a receiver of the Issuer, or the
         whole or any part of its property, or

                                       33
<PAGE>

         approving a petition filed against the Issuer seeking the bankruptcy
         or arrangement or reorganization of the Issuer under any applicable
         law or statute of the United States or the State of Tennessee and such
         order, judgment or decree shall not be vacated, set aside or stayed
         within sixty days from the date of the entry thereof, or (iii) under
         the provisions of any other law for the relief or aid of debtors, any
         court of competent jurisdiction shall assume custody or control of the
         Issuer or the whole or any substantial part of its property, and such
         custody or control shall not be terminated within ninety days from the
         date of assumption of such custody or control, and if as a result of
         any of the foregoing events described in clauses (i) to (iii) any
         court, trustee or receiver either (A) asserts jurisdiction over or
         attempts in any way to obtain possession of any part of the Trust
         Estate, including the Project or Installment Payments, or (B) seeks to
         disaffirm or reject any obligations of the Issuer under the Indenture,
         the Bonds or the Agreement;

                  (d) if the Company shall default in any of its obligations
         under the Agreement, the Deed of Trust or the Security Agreement and
         such default shall not have been remedied within the applicable period
         of time for remedy, therein or in Article XIII of the Agreement
         expressed; or

                  (e) if the Guarantor shall default in its obligations under
         the Guaranty Agreement;

then and in each and every case during the continuance of such event of default
unless cured by the Issuer within 60 days after written notice thereof (except
for an Event of Default specified in subsection (a) hereof, in which case
immediately) and unless the principal of all the Bonds shall have already become
due and payable, the Trustee, by notice in writing to the Issuer, may, and upon
the written request of the holders of not less than twenty-five per cent (25%)
in principal amount of the Bonds at the time then outstanding shall, declare the
principal of all the Bonds then outstanding hereunder, and the interest accrued
thereon, to be due and payable immediately, and upon any such declaration the
same shall become and shall be immediately due and payable, anything in this
Indenture or in the Bonds contained to the contrary notwithstanding.

         This provision, 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, the Issuer or the
Company shall pay to or shall deposit with the Trustee a sum sufficient to pay
all principal on the Bonds matured prior to such declaration and all matured
installments of interest (if any) upon all the Bonds, and the reasonable
expenses of the Trustee, and any and all other defaults known to the Trustee
(other than in the payment of principal and of interest on the Bonds due and
payable solely by reason of such declaration) shall have been made good or cured
or provisions adequate shall have been made therefor, then, and in every such
case, the holders of at least sixty-six and two-thirds per cent (66-2/3%) in
aggregate principal amount of the Bonds then outstanding, by written notice to
the Issuer and to the Trustee, may, on behalf of the holders of all the Bonds,
rescind and annul such declaration and its consequences, but no such rescission

                                       34
<PAGE>

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. The Trustee, in case of the happening of an Event of
Default specified in Section 7.01 hereof, may, and upon the written request of
the holders of more than 50% in aggregate principal amount of the Bonds then
outstanding, and upon being indemnified to its satisfaction, shall exercise any
or all rights under the Guaranty or any or all rights of the Issuer under the
Agreement including without limitation all rights of the Issuer to foreclose on
or take possession of the Project under the Deed of Trust or the Security
Agreement should the Company be in default under the Agreement.

         The Trustee may proceed to protect and enforce its rights and the
rights of the holders of the Bonds under this Indenture by a suit or suits in
equity or at law, either for the specific performance of any covenant or
agreement contained herein or in aid of the execution of any power therein
granted, or for the foreclosure of this Indenture, or for the enforcement of any
other appropriate legal or equitable remedy, as the Trustee, being advised by
counsel, may deem most effectual to protect and enforce any of the rights or
interests under the Bonds and/or this Indenture. All rights of action under this
Indenture or under any of the Bonds may be enforced by the Trustee without the
possession of any of the Bonds or the production thereof on any trial or other
proceeding relative thereto and any such suit or proceeding instituted by the
Trustee shall be brought in its name as Trustee, and any recovery of judgment
shall be for the ratable benefit of the holders of the Bonds.

         The Trustee, upon the bringing of a suit to foreclose this Indenture,
as a matter of right, without notice and without giving bond to the Issuer or
anyone claiming under it, may have a receiver appointed of all the mortgaged
property and of the earnings, income, rents, issues and profits thereof pending
such proceedings, with such powers as the court making such appointment shall
confer, including such powers as may be necessary or usual in such cases for the
protection, possession, control, management and operation of the mortgaged
property, and the Issuer does hereby irrevocably consent to such appointment.

         The Trustee is hereby appointed, and the successive respective holders
of the Bonds by taking and holding the same shall be conclusively deemed to have
so appointed the Trustee, the true and lawful attorney in fact of the respective
holders of the Bonds, with authority to make or file, in the respective names of
the holders of the Bonds or in behalf of all holders of the Bonds, as a class,
any proof of debt, amendment to proof of debt, petition or other documents; to
receive payment of all sums becoming distributable on account thereof; to
execute any other papers and documents and to do and perform any and all acts
and things for and in behalf of all holders of the Bonds as a class, as may be
necessary or advisable in the opinion of the Trustee, in order to have the
respective claims of the holders of the Bonds against the Issuer, the Company or
the Guarantor allowed in any equity receivership, insolvency, liquidation,
bankruptcy or other proceedings, to which the Issuer, the Company or the
Guarantor shall be a party. The Trustee shall have full power of substitution
and delegation in respect of any such powers. Upon the

                                       35
<PAGE>

occurrence of an event of default under the Agreement the Trustee may enforce
any and all rights of the Issuer thereunder.

         Section 7.03. The proceeds or avails of any sale pursuant to this
Article VII shall be paid to and applied by the Trustee as follows:

         (1)      To the payment of costs and expenses of foreclosure or suit,
                  if any, and of such sale and the reasonable compensation of
                  the Trustee, its agents, attorneys and counsel, and of all
                  proper expenses, liabilities and advances incurred or made
                  hereunder by the Trustee or by any holder or holders of the
                  Bonds, and of all taxes, assessments or liens superior to the
                  lien of these presents, except any taxes, assessments or other
                  superior liens subject to which said sale may have been made;
                  then

         (2)      (a) Unless the principal of all the Bonds shall have become or
                  shall have been declared due and payable, all such moneys
                  shall be applied:

                  First: to the payment to the persons entitled thereto of all
                  installments of interest then due and payable in the order in
                  which such installments become due and payable and, if the
                  amount available shall not be sufficient to pay in full any
                  particular installment, then to the payment, ratably,
                  according to the amounts due on such installment, to the
                  persons entitled thereto, without any discrimination or
                  preference except as to any difference in the respective rates
                  of interest specified in the Bonds;

                  Second: to the payment to the persons entitled thereto of the
                  unpaid principal of any of the Bonds which shall have become
                  due and payable (other than Bonds called for redemption for
                  the payment of which moneys are held pursuant to the
                  provisions of this Indenture), in the order of their due
                  dates, with interest on the principal amount of the Bonds at
                  the respective rates specified therein from the respective
                  dates upon which the Bonds became due and payable, and, if the
                  amount available shall not be sufficient to pay in full the
                  principal of the Bonds due and payable on any particular date,
                  together with the interest, then to the payment first of the
                  interest, ratably, according to the amount of the interest due
                  on that date, and then to the payment of the principal,
                  ratably, according to the amount of the principal due on that
                  date, to the persons entitled thereto without any
                  discrimination.

                  Third:  to the payment of the interest on and the principal of
                  the Bonds, to the purchase and retirement of Bonds and to the
                  redemption of Bonds, all in accordance with the provisions of
                  Article V of this Indenture.

                  (b) If the principal of all the Bonds shall have become or
                  shall have been declared

                                       36
<PAGE>

                  due and payable, all the moneys shall be applied to the
                  payment of the principal and interest then due and unpaid upon
                  the Bonds, without preference or priority of principal over
                  interest or of interest over principal, or of any installment
                  of interest over any other installment of interest, or of any
                  Bond over any other Bond, ratably, according to the amounts
                  due respectively for principal and interest, to the persons
                  entitled thereto without any discrimination of preferences
                  except as to any difference in the respective rates of
                  interest specified in the Bonds.

         (3)      To the payment of the surplus, if any, to the Company, its
                  successors and assigns, pursuant to Section 4.10 hereof, or to
                  whomsoever may be lawfully entitled to receive the same.

         Section 7.04. No delay or omission of the Trustee or of any holder of
any of the Bonds to exercise any right or power arising from any default on the
part of the Issuer shall exhaust or impair any such right or power or prevent
its exercise during the continuance of such default. No waiver by the Trustee or
Bondholders of any such default, whether such waiver be full or partial, shall
extend to or be taken to affect any subsequent default, or to impair the rights
resulting therefrom, except as may be otherwise provided herein. No remedy
hereunder is intended to be exclusive of any other remedy but each and every
remedy shall be cumulative and in addition to any and every other remedy given
hereunder or otherwise existing.

         Section 7.05. No Bondholder shall have any right to institute or
prosecute any suit or proceeding at law or in equity for the foreclosure hereof,
for the appointment of a receiver of the Issuer, for the enforcement of any of
the provisions hereof or of any remedies hereunder in respect to the mortgaged
property unless the Trustee, after a request in writing by the holders of
twenty-five per cent (25%) in aggregate principal amount of the Bonds then
outstanding, provided, that the holders of the Bonds shall have offered to the
Trustee such reasonable indemnity as it may require against the costs, expenses
and liabilities to be incurred therein or thereby, shall have neglected for 60
days to take such action; provided, however, that the right of any holder of any
Bond to receive payment of the principal thereof and/or interest thereon on or
after the respective due dates expressed therein or to institute suit for the
enforcement of any such payment shall not be impaired or affected without the
consent of such holder.

         Section 7.06. Notwithstanding any provision herein to the contrary or
the occurrence and continuance of any event of default by the Issuer hereunder,
so long as the Company is not in default under the Agreement none of the Issuer,
the Trustee nor any Bondholder or Bondholders shall have any right to accelerate
or otherwise declare due and payable the remaining unpaid installments under the
Agreement or take any action or initiate any proceedings under the Deed of Trust
or the Security Agreement.

                                  ARTICLE VIII

                                       37
<PAGE>

                             Concerning the Trustee

         Section 8.01. The Trustee shall, prior to an Event of Default as
defined in Section 7.01, and after the curing of all such events of default
which may have occurred, perform such duties and only such duties as are
specifically set forth in this Indenture and shall have no implied duties
hereunder. The Trustee shall, during the existence of any such Event of Default
(which has not been cured) exercise such rights and powers vested in it by this
Indenture and may in its discretion, but shall have no affirmative duty to, take
such other actions as it deems to be in the best interest of the Bondholders,
exercising such discretion with the same degree of care and skill in their
exercise as a prudent man would exercise or use under the circumstances in the
conduct of his own affairs.

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

                  (a)  prior to such an Event of Default hereunder and after the
         curing of all such events of default which may have occurred, in the
         absence of bad faith on the part of the Trustee, the Trustee may
         conclusively rely, as to the truth of the statements and the
         correctness of the opinions expressed therein, upon any Officers'
         Certificate, or Opinion of Counsel furnished to the Trustee and
         believed by it to be genuine and executed by the person or persons
         authorized to furnish the same, unless the Trustee knows that the
         matters upon which the certificate or opinion is based are erroneous;

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

                  (1)  The Trustee shall not be liable for any error of
                       judgment made in good faith by a Responsible Officer
                       or Officers of the Trustee unless the Trustee was
                       grossly negligent in ascertaining or failing to ascertain
                       the pertinent facts;

                  (2)  The Trustee shall not be liable with respect to any
                       action taken or omitted to be taken by it in good
                       faith in accordance with the direction of the holders
                       of more than 50% (or such lesser or greater percentage as
                       is specifically required or permitted by this Indenture)
                       in aggregate principal amount of all Bonds at the time
                       outstanding relating to the time, method and place of
                       conducting any proceeding for any remedy available to the
                       Trustee.

         Section 8.02. Except as otherwise provided in Section 8.01,

                  (a)  the Trustee may rely upon the authenticity of, and the
         truth of the

                                       38
<PAGE>

         statements and the correctness of the opinions expressed in, and shall
         be protected in acting upon any resolution, certificate, statement,
         instrument, opinion, report, notice, notarial seal, stamp,
         acknowledgement, verification, request, consent, order, Bond or other
         paper or documents believed by it to be genuine and to have been signed
         or affixed or presented by the proper party or parties;

                  (b) any notice, request, direction, election, order or demand
         of the Issuer mentioned herein shall be sufficiently evidenced by an
         instrument signed in the name of the Issuer by any officer of the
         Issuer (unless other evidence in respect thereof be herein specifically
         prescribed), and any resolution of the Board of Directors of the Issuer
         may be evidenced to the Trustee by a Certified Resolution;

                  (c) in the administration of the trusts of the Indenture, the
         Trustee may execute any of the trusts or powers hereof directly or
         through its agents or attorneys and the Trustee may consult with
         counsel (who may be but need not necessarily be counsel for the Issuer
         or the Company) and the opinion or advice of such counsel shall be full
         and complete authorization and protection in respect of any action
         taken or suffered by it hereunder in good faith and in accordance with
         the opinion of such counsel;

                  (d) whenever in the administration of the trusts of this
         Indenture, the Trustee 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 gross negligence
         or bad faith on the part of the Trustee, be deemed to be exclusively
         proved and established by an Officers' Certificate of the Issuer; and
         such Officers' Certificate of the Issuer shall, in the absence of gross
         negligence or bad faith on the part of the Trustee, be full warrant to
         the Trustee for any action taken or suffered by it under the provisions
         of this Indenture upon the faith thereof, but in its discretion the
         Trustee may in lieu thereof accept other evidence of such matter or may
         require such further or additional evidence as it may deem reasonable;

                  (e) the recitals herein and in the Bonds (except the Trustee's
         certificate of authentication thereon) shall be taken as the statement
         of the Issuer and shall not be considered as made by, or imposing any
         obligation or liability upon, the Trustee. The Trustee makes no
         representations as to the value or condition of the trust estate or any
         part thereof, or as to the title of the Issuer thereto, or as to the
         security afforded thereby or hereby, or as to the validity of this
         Indenture or of the Bonds issued hereunder, and the Trustee shall incur
         no liability or responsibility in respect of any of such matters;

                  (f) the Trustee shall not be personally liable in case of
         entry by it upon the Trust Estate for debts contracted or liability or
         damages incurred in the management or operation of the Trust Estate.
         The Trustee shall not in any event be required to take, defend or
         appear in any legal action or proceeding hereunder or to exercise any
         of the trusts or powers hereof unless it shall first be adequately
         indemnified to its satisfaction

                                       39
<PAGE>

         against the costs, expenses and liabilities which may be incurred
         thereby. Every provision of this Indenture relating to the conduct
         or affecting the liability of or affording protection to the Trustee
         shall be subject to the provisions of this subsection (f);

                  (g) the Trustee shall not be required to ascertain or inquire
         as to the performance or observance of any of the covenants or
         agreements herein or in the Agreement or any contracts or securities
         assigned or conveyed to or mortgaged with the Trustee hereunder
         contained to be performed or observed by the Issuer or any party to the
         Agreement or such contracts or securities; nor shall the Trustee have
         any obligation, duty or liability under any of such agreements. The
         Trustee shall not be required to take notice or be deemed to have
         notice or actual knowledge of any default or Event of Default specified
         in Section 7.01(b), (c), (d) or (e) hereunder unless the Trustee shall
         receive from the Issuer or the holder of any Bond written notice
         stating that a default or Event of Default hereunder has occurred and
         specifying the same, and in the absence of such notice the Trustee may
         conclusively assume that there is no such default or Event of Default.
         Every provision contained in this Indenture or in the Agreement or any
         such contract or security wherein it is provided that the duty of the
         Trustee to take action or omit to take action or to permit the Issuer
         or any party to any such agreement to do any act or thing depends on
         the occurrence and continuance of such default hereunder or thereunder
         shall be subject to the provisions of this subsection (g);

                  (h) no duty with respect to effecting or maintaining insurance
         shall rest upon the Trustee and the Trustee shall not be responsible
         for any loss by reason of want or insufficiency of insurance or by
         reason of the failure of any insurer in which the insurance is carried
         to pay the full amount of any loss against which it may have insured
         the Issuer or any other person;

                  (i) it shall be no part of the duty of the Trustee to see to
         any recording, filing or registration of this Indenture, the Agreement,
         the Deed of Trust, the Security Agreement, any contracts or securities
         assigned or conveyed to or mortgaged with the Trustee hereunder, any
         instrument of further assurance, or any supplement to any of said
         instruments, except for continuation statements which may from time to
         time be required under the Tennessee Uniform Commercial Code, or to see
         to the payment of any fees, charges or taxes in connection therewith,
         or to give any notice thereof, or be under any duty in respect to any
         tax or assessment or other governmental charge which may be levied or
         assessed on the Trust Estate or any part thereof or against the Issuer.
         The Trustee shall be under no obligation to see to the payment or
         discharge of any liens upon the Trust Estate;

                  (j) the Trustee shall be under no duty to confirm or verify
         any financial or other statements or reports or certificates furnished
         pursuant to any provisions hereof, and shall be under no other duty in
         respect of the same except to retain the same in its files and permit
         the inspection of the same at reasonable times by the holder of any
         Bond;

                                       40
<PAGE>

                  (k)  the Trustee shall not be under any obligation to give any
         consent, enter into any agreement, release any property or to take any
         other action which is discretionary with the Trustee under the
         provisions hereof except on written request of the holders of not less
         than any applicable specified percentage provided for in this Indenture
         or if no percentage is specified then sixty-six and two-thirds per cent
         (66-2/3%) in principal amount of the Bonds outstanding hereunder;

                  (l)  none of the provisions contained in this Indenture shall
         require the Trustee to expend or risk its own funds or otherwise incur
         personal financial liability in the performance of any of its duties or
         in the exercise of any of its rights or powers; and

                  (m)  the Trustee shall not be accountable for the use of
         proceeds from the sale of the Bonds disbursed by it in accordance with
         the provisions of this Indenture.

         Section 8.03. The Trustee makes no representations as to the validity
or sufficiency of this Indenture, the Agreement, the Deed of Trust, the Security
Agreement, the Guaranty Agreement or of the Bonds. The Trustee shall not be
accountable for the use or application by the Issuer of any of the Bonds
authenticated or delivered hereunder or of the proceeds of such Bonds unless
deposited with the Trustee.

         Section 8.04. The Trustee and its officers and directors may acquire
and hold, or become the pledgee of, Bonds and otherwise deal with the Issuer in
the manner and to the same extent and with like effect as though it were not
trustee hereunder.

         Section 8.05. All moneys received by the Trustee shall, until used or
applied as herein provided, be held in trust for the purposes for which they
were received and shall be segregated from other funds. The Trustee shall be
under no liability for interest on any moneys received by it hereunder except
such as it may agree with the Issuer to pay thereon.

         Section 8.06. Subject to the provisions of Section 6.17 of this
Indenture, the Issuer covenants and agrees to pay to the Trustee from time to
time, and the Trustee shall be entitled to, reasonable compensation for all
services rendered by it in the execution of the trusts hereby created and in the
exercise and performance of any of the powers and duties hereunder of the
Trustee, which compensation shall not be limited by any provision of law in
regard to the compensation of a trustee of an express trust, and the Issuer will
pay or reimburse the Trustee upon its request for all expenses, disbursements
and advances incurred or made by the Trustee 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 subject to this Indenture, or any supplemental indenture,
as security for the Bonds, the Trustee, if and to the extent authorized by a
receivership, bankruptcy or other court of competent jurisdiction or by the

                                       41
<PAGE>

instrument subjecting such property to the provisions of this Indenture as such
security for the Bonds, shall be entitled to make advances for the purpose of
preserving such property or of discharging tax liens or other prior liens or
encumbrances thereon. The Issuer also covenants to indemnify the Trustee for,
and to hold it harmless against, any loss, liability, expense or advance
incurred or made without negligence or bad faith on the part of the Trustee,
arising out of or in connection with the acceptance of this trust, including the
costs and expenses of defending itself against any claim or liability in the
premises. The obligations of the Issuer under this Section 8.06 to compensate
the Trustee for services and to pay or reimburse the Trustee for expenses,
disbursements, liabilities and advances shall constitute additional indebtedness
hereunder. Such additional indebtedness shall while an event of default
hereunder is continuing have priority over the Bonds in respect of all property
and funds held or collected by the Trustee as such.

         Section 8.07. There shall at all times be a trustee hereunder which
shall be a banking corporation or banking association organized and doing
business under the laws of the United States or any State authorized under such
laws to exercise corporate trust powers, having its principal office and place
of business in any State, having a combined capital and surplus of at least
Twenty-Five Million Dollars ($25,000,000), and subject to supervision or
examination by federal or state authority. If such corporation publishes 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 8.07 the combined capital and surplus of such corporation shall be
deemed to be its combined capital and surplus as set forth in its most recent
report of condition so published. In case at any time the Trustee shall cease to
be eligible in accordance with the provisions of this Section 8.07, the Trustee
shall resign immediately in the manner and with the effect specified in Section
8.08.

         Section 8.08. (a) The Trustee may at any time resign by giving written
notice by first class mail to the Issuer, to the Company and to each Bondholder.
Upon receiving such notice of resignation, the Issuer, with the prior written
approval of the Company, shall promptly appoint a successor trustee by an
instrument in writing executed by order of its Board of Directors. If no
successor trustee shall have been so appointed and have accepted appointment
within thirty (30) days after the mailing of such notice of resignation, the
resigning trustee may petition any court of competent jurisdiction for the
appointment of a successor trustee, or any Bondholder who has been a bona fide
holder of a Bond or Bonds for at least six months may, on behalf of himself and
others similarly situated, petition any such court for the appointment of a
successor trustee. Such court may thereupon, after such notice, if any, as it
may deem proper and prescribe, appoint a successor trustee.

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

                  (1)      The Trustee 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 Issuer
                           or by any Bondholder who has been a bona fide holder
                           of a Bond or Bonds for at least six months, or

                                       42
<PAGE>

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

         then in any such case, the Issuer may remove the Trustee and, with the
         prior written consent of the Company, appoint a successor trustee by an
         instrument in writing executed by order of its Board of Directors, or
         any such Bondholder may, on behalf of himself and all others similarly
         situated, petition any court of competent jurisdiction for the removal
         of the Trustee and the appointment of a successor trustee. Such court
         may thereupon, after such notice, if any, as it may deem proper and
         prescribe, remove the Trustee and appoint a successor trustee.

         (c) The holders of more than 50% in aggregate principal amount of all
the Bonds at the time outstanding may at any time remove the Trustee and appoint
a successor trustee by an instrument or concurrent instruments in writing signed
by such Bondholders.

         (d) Any resignation or removal of the Trustee and appointment of a
successor trustee pursuant to any of the provisions of this Section 8.08 shall
become effective upon acceptance of appointment by the successor trustee as
provided in Section 8.09.

         Section 8.09. Any successor trustee appointed as provided in Section
8.08 shall execute, acknowledge and deliver to the Issuer 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 like effect as if originally named as
trustee herein; but, nevertheless, on the Written Request of the Issuer 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 Issuer shall execute any
and all instruments in writing 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 8.09,

                                       43
<PAGE>

the Issuer shall give written notice by first class mail to
each Bondholder of the succession of such trustee to the trusts hereunder. If
the Issuer fails to give such notice within ten (10) days after acceptance of
appointment by the successor trustee, the successor trustee shall cause such
notice to be mailed at the expense of the Issuer.

         Section 8.10. Any corporation into which the Trustee may be merged or
with which it may be consolidated, or any corporation resulting from any merger
or consolidation to which the Trustee shall be a party, or any corporation
succeeding to the business of the Trustee, shall be the successor of the Trustee
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 shall be eligible under
the provisions of Section 8.07.

         Section 8.11. Whenever the Trustee gives notice to the Bondholders of
any Event of Default, it shall also furnish a copy of such notice to the
Underwriter.

         Section 8.12. The Trustee shall provide the rating agency whose credit
rating on any of the Bonds is in effect with prompt written notice of (i) any
change of Trustee hereunder, (ii) any material change in the Loan Agreement, the
Deed of Trust, the Security Agreement, the Indenture or the Guaranty Agreement,
(iii) payment of all the Bonds, (iv) expiration of the Guaranty Agreement, or
(v) defeasance of all of the Bonds in accordance with Article XI hereof. The
obligations of the Trustee under this Section shall survive defeasance of the
Bonds in accordance with Article XI hereof.

                                   ARTICLE IX

                        Evidence of Rights of Bondholders

         Section 9.01. 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 and of the Issuer if
made in the manner provided in this Article.

         Section 9.02. 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 acknowledgements of deeds, certifying that the person signing such request,
consent or other instrument acknowledged to him the execution thereof. Where
such execution is by an officer of a corporation or association or a member of a
partnership on behalf of such corporation, association or partnership such
affidavit or certificate shall also constitute

                                       44
<PAGE>

sufficient proof of his authority.

         Section 9.03. The ownership of the Bonds shall be proved by the
register of such Bonds. Any request, consent or vote of the holder of any Bond
shall bind every future holder of the same Bond and the holder of every Bond
issued in exchange therefor or in lieu thereof, in respect of anything done or
suffered to be done by the Trustee or the Issuer in pursuance of such request,
consent or vote.

         Section 9.04. 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
Issuer, the Company, the Guarantor or by any other 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 faith may be regarded as
outstanding for the purpose of this Section 9.04 if the pledgee shall establish
to the satisfaction of 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 common control with the Issuer or any other obligor on
the Bonds. In case of a dispute as to such right, any decision by the Trustee
taken in good faith upon the advice of counsel shall be full protection to the
Trustee.

                                    ARTICLE X

                             Supplemental Indenture

         Section 10.01. The Issuer, when authorized by resolution of its Board
of Directors, and the Trustee from time to time and at any time, subject to the
conditions and restrictions in this Indenture contained, may, with the prior
written consent of the Company and the Guarantor, enter into an indenture or
indentures supplemental hereto, which indenture or indentures thereafter shall
form a part hereof, for any one or more or all of the following purposes:

                  (a) to add to the covenants and agreements of the Issuer in
         this Indenture contained, other covenants and agreements thereafter to
         be observed or to surrender any right or power herein reserved or
         conferred upon the Issuer;

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

                                       45
<PAGE>

                  (c) to subject, describe or redescribe any property subjected
         or to be subjected to the lien of this Indenture;

                  (d) to modify, amend or supplement this Indenture or any
         indenture supplemental hereto in such manner as to permit the
         qualification hereof and thereof under the Trust Indenture Act of 1939
         or any similar federal statute hereafter in affect, 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;

                  (e) to provide for additional series of Bonds to the extent
         permitted by this Indenture; and

                  (f) to effect any other amendment to this Indenture which, in
         the judgment of the Trustee, will not adversely affect the interests of
         the holders.

         Any supplemental indenture authorized by the provisions of this Section
10.01 may be executed by the Issuer and the Trustee without the consent of the
holders of any of the Bonds at the time outstanding, notwithstanding any of the
provisions of Section 10.02, but 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.

         Section 10.02. With the consent (evidenced as provided in Article IX)
of the holders of not less than sixty-six and two-thirds per cent (66-2/3%) in
aggregate principal amount of the Bonds at the time outstanding and with the
prior written consent of the Company and the Guarantor, the Issuer, when
authorized by a resolution of its Board of Directors, 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 provisions to or changing in any manner or
eliminating any of the provisions of this Indenture or of any supplemental
indenture; provided, however, that no such supplemental indenture shall (1)
extend the fixed maturity of the Bonds or reduce the rate of interest thereon or
extend the time of payment of interest, or reduce the amount of the principal
thereof, or reduce any premium payable on the redemption thereof, without the
consent of the holder of each Bond so affected, or (2) reduce the aforesaid
percentage of holders of Bonds required to approve any such supplemental
Indenture, or (3) permit the creation of any lien on the properties mortgaged
and conveyed hereunder prior to or on a parity with the lien of this Indenture
(except for the issuance of additional Bonds permitted hereunder) or deprive the
holders of the Bonds of the lien created by this Indenture upon said properties,
without the consent of the holders of all the Bonds then outstanding. Upon
receipt by the Trustee of a Certified Resolution authorizing the execution of
any such supplemental indenture, and upon the filing with the Trustee of
evidence of the consent of Bondholders, as aforesaid, the Trustee shall join
with the Issuer in the execution of such supplemental indenture unless such
supplemental indenture 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

                                       46
<PAGE>

supplemental indenture.

         It shall not be necessary for the consent of the Bondholders under this
Section 10.02 to approve the particular form of any proposed supplemental
indenture, but it shall be sufficient if such consent shall approve the
substance thereof.

         Section 10.03. Upon the execution of any supplemental indenture
pursuant to the provisions of this Article X, this Indenture shall be and be
deemed to be modified and amended in accordance therewith and the respective
rights, duties and obligations under this Indenture of the Issuer, the Trustee
and all holders of Bonds outstanding thereunder shall thereafter be determined,
exercised and enforced hereunder subject in all respects to such modifications
and amendments, and all the terms and conditions of any such supplemental
indenture shall be and be deemed to be part of the terms and conditions of this
Indenture for any and all purposes.

         Section 10.04. The Trustee in the absence of bad faith may rely on an
Opinion of Counsel as conclusive evidence that any supplemental indenture
executed pursuant to the provisions of this Article X complies with the
requirements of this Article X.

         Section 10.05. Bonds authenticated and delivered after the execution of
any supplemental indenture pursuant to the provisions of this Article X may bear
a notation, in form approved by the Trustee, 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, to any
modification of this Indenture contained in any such supplemental indenture, may
be prepared by the Issuer, authenticated by the Trustee 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 XI

                          Defeasance; Unclaimed Moneys

         Section 11.01. If the Issuer shall pay and discharge the entire
indebtedness on all Bonds outstanding hereunder in any one or more of the
following ways, to-wit:

         A.       by well and truly paying or causing to be paid the principal
                  of (including redemption premium, if any) and interest on
                  Bonds outstanding hereunder, as and when the same become due
                  and payable;

         B.       by (i) depositing or causing to be deposited with the Trustee,
                  in trust, at or before the date of maturity or redemption,
                  sufficient money or Government Obligations the principal of
                  and interest on which, when due and payable, will provide
                  sufficient moneys to pay or redeem the Bonds outstanding
                  hereunder and to pay

                                       47
<PAGE>

                  interest thereon until the maturity or redemption date and
                  (ii) delivery to the Trustee an opinion of nationally
                  recognized bond counsel that such deposit and redemption will
                  not cause interest on the Bonds to be includable in gross
                  income for federal income tax purposes; and/or

         C.       by delivering to the Trustee, for cancellation by it, Bonds
                  outstanding hereunder;

and if the Issuer shall also pay or cause to be paid all other sums payable
hereunder by the Issuer, then and in that case this Indenture shall cease,
determine and become null and void, and thereupon the Trustee shall, upon
Written Request of the Issuer, and upon receipt by the Trustee of an Officers'
Certificate of the Issuer 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 Issuer for any
expenditures which it may thereafter incur in connection herewith, subject to
the provisions of Section 6.17 of this Indenture.

         The Issuer may at any time surrender to the Trustee for cancellation by
it any Bonds previously authenticated and delivered hereunder; which the Issuer
may have acquired in any manner whatsoever, and such Bonds, upon such surrender
and cancellation, shall be deemed to be paid and retired.

         Section 11.02. Upon the deposit with the Trustee, in trust, at or
before maturity, of moneys or Government Obligations in the necessary amount to
pay or redeem Bonds outstanding hereunder (whether upon or prior to their
maturity or the redemption date of such Bonds), and to pay interest thereon
until the maturity or redemption date provided that if such Bonds are to be
prior to the maturity thereof notice of such redemption shall have been given as
in Article V provided or provisions satisfactory to the Trustee shall have been
made for the giving of such notice, all liability of the Issuer in respect of
such Bonds shall cease, terminate and be completely discharged and the holders
thereof shall thereafter be entitled only to payment out of the money or
Government Obligations deposited with the Trustee as aforesaid for their
payment, subject, however, to the provisions of Section 11.03.

         Section 11.03. Notwithstanding any provisions of this Indenture, any
moneys deposited with the Trustee or any other paying agent in trust for the
payment of the principal of, or interest or premium on, any Bond then due and
payable shall be retained and not invested. Any such moneys remaining unclaimed
for three (3) years after the principal of such Bond outstanding hereunder 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 Company
upon its Written Request, and the holder of such Bond shall thereafter be
entitled to look only to the Company for repayment thereof, and all liability of
the Trustee or any other paying agent with respect to such moneys shall
thereupon cease; provided, however, that before the repayment of such moneys to
the Company as aforesaid, the Trustee or other paying agent, as the case may be,
may (at the cost

                                       48
<PAGE>

of the Company but subject to Section 6.17 hereof) first publish a notice, in
such form as may be deemed appropriate by the Trustee or such paying agent, in
respect of the Bonds so payable and not presented and in respect of the
provisions relating to the repayment to the Company of the moneys held for the
payment thereof. Such notice shall be published at least once in an Authorized
Newspaper. In the event of the repayment of any such moneys to the Company as
aforesaid, the holders of the Bonds in respect to which such moneys were
deposited shall thereafter be deemed to be unsecured creditors of the Company
for amounts equivalent to the respective amounts deposited for the payment of
such Bonds and so repaid to the Company (without interest thereon).
Notwithstanding the foregoing, the Trustee shall, upon the Written Request of
the Company, repay such moneys to the Issuer at any time earlier than three (3)
years if failure to repay such moneys to the Issuer within such earlier period
shall give rise to the operation of any escheat statute under applicable state
law.

                                   ARTICLE XII

                            Miscellaneous Provisions
         Section 12.01. All the covenants, stipulations, promises and agreements
in this Indenture contained, by or in behalf of the Issuer, shall bind and inure
to the benefit of its successors and assigns, whether so expressed or not.

         Section 12.02. 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
Issuer, the Trustee 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
covenants, conditions or provisions 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 Issuer, the Trustee and the holders of the Bonds
issued hereunder, provided, however, this Section 12.02 shall not diminish,
restrict or otherwise adversely affect the rights or benefits acquired by the
Company or the Guarantor by assignments or subrogation from the Issuer, Trustee
or the holders of the Bonds issued hereunder.

         Section 12.03. 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 12.04. Whenever in this Indenture provision is made for the
cancellation by the Trustee and the delivery to the Issuer of any Bonds, the
Trustee may, unless the Issuer shall by Written Request direct otherwise, in
lieu of such cancellation and delivery, destroy such Bonds and deliver a
certificate of such destruction to the Issuer.

         Section 12.05. 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

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invalidity, illegality or unenforceability shall not affect any other provisions
of this Indenture or the Bonds, but this Indenture and the Bonds shall be
construed as if such invalid or illegal or unenforceable provision had never
been contained herein.

         Section 12.06. Any notice to or demand upon the Trustee may be served,
or presented, and such demand may be made, at the main office of the Trustee,
NationsBank Plaza, Nashville, Tennessee 37219, Attention: Corporate Trust
Department, and shall be deemed given only upon actual receipt by the Trustee.
Any notice to or demand upon the Issuer, the Company, the Guarantor or the
Underwriter shall be deemed to have been sufficiently given or served for all
purposes by being deposited, postage prepaid, in a post office letter box
addressed (a) if to the Issuer, to it at 2021 Gallatin Road North, Suite 132,
Madison, Tennessee 37115, or such other address as may be filed in writing by
the Issuer with the Trustee, (b) if to the Company as provided in Section 15.07
of the Loan Agreement, (c) if to the Guarantor, as provided in Section 15.07 of
the Loan Agreement for copies of notices to the Company, and (d) if to the
Underwriter, to it at 330 Commerce Street, Nashville, Tennessee 37201,
Attention: Municipal Finance Department, or at such other address as it from
time to time may have designated by written notice to the Company and the
Trustee.

         Section 12.07. 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 such counterparts, or as many of them as the Issuer and the
Trustee shall preserve undestroyed, shall together constitute but one and the
same instrument.

         Section 12.08. No recourse under or upon any obligation, covenant or
agreement contained in this Indenture, or in any Bond hereby secured, or under
any judgment obtained against the Issuer, or to the enforcement of any
assessment or by any legal or equitable proceeding by virtue of any constitution
or statute otherwise or under any circumstances, under or independent of this
Indenture, shall be had against any incorporator, member, director, or officer,
as such past, present or future, of the Issuer, either directly or through the
Issuer, or otherwise, for the payment for or to the Issuer or any receiver
thereof, or for or to the holder of any Bond issued hereunder or otherwise, of
any sum that may be due and unpaid by the Issuer upon any such Bond. Any and all
personal liability of every nature, whether at common law or in equity, or by
statute or by constitution or otherwise, of any such incorporator, member,
director, or officer as such, to respond by reason of any act or omission on his
part or otherwise, for the payment for or to the Issuer or any receiver thereof,
or for or to the holder of any Bond issued hereunder or otherwise, of any sum
that may remain due and unpaid upon the Bonds hereby secured or any of them, is
hereby expressly waived and released as a condition of and consideration for the
execution of this Indenture and the issue of such Bonds.

         Section 12.09. The Metropolitan Government of Nashville and Davidson
County, Tennessee shall not in any event be liable for the payment of the
principal of, premium, if any, or interest on any of the Bonds issued hereunder,
or for the performance of any pledge, mortgage, obligation or agreement of any
kind whatsoever herein or indebtedness by the Issuer, and none of

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the Bonds of the Issuer issued hereunder or any of its agreements or obligations
herein or otherwise shall be construed to constitute an indebtedness of the
Metropolitan Government of Nashville and Davidson County, Tennessee within the
meaning of any constitutional or statutory provision whatsoever.

         Section 12.10. This Indenture shall be governed exclusively by the
applicable laws of the State of Tennessee.

         Section 12.11. If, at the time any payment hereunder is required to be
made to the Company, the Company is not in existence, then such payment shall be
made to the person or entity lawfully entitled thereto.

         Section 12.12. If the date for making any payment or the last date for
performance of any act or the exercising of any right, as provided in this
Indenture, shall not be a Business Day, such payment may, unless otherwise
provided in this Indenture or the Agreement, be made or act performed or right
exercised on the next succeeding Business Day with the same force and effect as
if done on the nominal date provided in this Indenture, and no interest shall
accrue for the period after such nominal date.

         IN WITNESS WHEREOF, THE INDUSTRIAL DEVELOPMENT BOARD OF THE
METROPOLITAN GOVERNMENT OF NASHVILLE AND DAVIDSON COUNTY has caused these
presents to be signed in its name and behalf by its ___________ Chairman and its
__________ Secretary and to evidence its acceptance of the trusts hereby created
NATIONSBANK OF TENNESSEE, N.A., has caused these presents to be signed in its
name and behalf by its ____________________ and its ___________________ all as
of the first day of May, 1993.

                                              THE INDUSTRIAL DEVELOPMENT BOARD
                                              OF THE METROPOLITAN GOVERNMENT OF
                                              NASHVILLE AND DAVIDSON COUNTY

                                              By:
                                                 ------------------------------
                                                                       Chairman

-----------------------
              Secretary

                                              NATIONSBANK OF TENNESSEE, N.A.,
                                                as Trustee

                                                     By:
                                                        ------------------------

ATTEST:

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

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