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                            STOCK PURCHASE AGREEMENT

                                 BY AND BETWEEN

                                H. WAYNE HUIZENGA

                                       AND

                                 OHM CORPORATION

                           DATED AS OF MARCH 28, 1995







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                                TABLE OF CONTENTS



Section                                                                                                        Page
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RECITALS ..................................................................................................      1

ARTICLE I.  ISSUANCE AND PURCHASE OF COMMON STOCK AND OPTIONS .............................................      1

     1.1      Sale of Common Stock; Issuance of Options ...................................................      1
     1.2      Legend ......................................................................................      2

ARTICLE II.  CLOSING ......................................................................................      2

ARTICLE III.  REPRESENTATIONS AND WARRANTIES OF THE ISSUER ................................................      3

     3.1      Corporate Status ............................................................................      3
     3.2      Power and Authority .........................................................................      3
     3.3      Non-Contravention ...........................................................................      3
     3.4      Consents/Approvals ..........................................................................      4
     3.5      Enforceability ..............................................................................      4
     3.6      Capitalization ..............................................................................      4
     3.7      SEC Reports .................................................................................      5
     3.8      Governing Documents .........................................................................      5
     3.9      Financial Statements ........................................................................      5
     3.10     Changes Since December 31, 1994. ............................................................      5
     3.11     Litigation. .................................................................................      5

ARTICLE IV.  REPRESENTATIONS AND WARRANTIES OF INVESTOR ...................................................      6

     4.1      Power and Authority .........................................................................      6
     4.2      Non-Contravention ...........................................................................      6
     4.3      Consents/Approvals ..........................................................................      6
     4.4      Enforceability ..............................................................................      6
     4.5      Affiliate of WMX Technologies, Inc. .........................................................      7
     4.6      Investment Intent ...........................................................................      7
     4.7      Investor Knowledge. .........................................................................      7
     4.8      No Commissions ..............................................................................      7

ARTICLE V.  COVENANTS .....................................................................................      8

     5.1      Covenants of the Issuer and the Investor ....................................................      8
     5.2      Additional Covenant of Investors ............................................................      8







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                                TABLE OF CONTENTS
                                   (CONTINUED)



Section                                                                                                        Page
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ARTICLE VI.  DEFINITIONS ..................................................................................      9

     6.1      Defined Terms ...............................................................................      9
     6.2      Other Definitional Provisions ...............................................................     11

ARTICLE VII.  REGISTRATION RIGHTS .........................................................................     12

     7.1      Transfer of Registration Rights .............................................................     12
     7.2      Piggyback Registration ......................................................................     12
     7.3      Holder Requested Registration ...............................................................     13
     7.4      Registration Procedures .....................................................................     15
     7.5      Further Information .........................................................................     17
     7.6      Registration During Holding Period ..........................................................     17

ARTICLE VIII.  INDEMNIFICATION ............................................................................     17

     8.1      Indemnification Relating to Registration Rights .............................................     17
     8.2      Indemnification Procedures ..................................................................     19

ARTICLE IX.  MISCELLANEOUS ................................................................................     20

     9.1      Notices .....................................................................................     20
     9.2      Non-Waiver of Remedies and Actions ..........................................................     21
     9.3      Headings ....................................................................................     21
     9.4      Counterparts ................................................................................     21
     9.5      Successors and Assigns ......................................................................     21
     9.6      Survival ....................................................................................     21
     9.7      Enforceability ..............................................................................     21
     9.8      Law Governing ...............................................................................     22
     9.9      Severability ................................................................................     22
     9.10     Remedies ....................................................................................     22
     9.11     Expenses ....................................................................................     22
     9.12     Entire Agreement ............................................................................     22








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                            STOCK PURCHASE AGREEMENT

                  This STOCK PURCHASE AGREEMENT (this "Agreement") is entered
into as of March 28, 1995, by and between H. WAYNE HUIZENGA (together with his
permitted successors and assigns, the "Investor"), and OHM CORPORATION, an Ohio
corporation (together with its permitted successors and assigns, the "Issuer").
Capitalized terms used herein but not otherwise defined herein are defined in
Section 6.1.

                                    RECITALS

                  WHEREAS, subject to the terms and conditions set forth herein,
Investor desires to purchase, and Issuer desires to issue and sell to Investor,
certain shares of Issuer's common stock, par value $.10 per share (the "Common
Stock").

                  WHEREAS, concurrently herewith, the Issuer and Investor are
entering into two option agreements providing the terms and conditions on which
Investor may acquire up to an additional one million (1,000,000) shares of
Common Stock from the Issuer (the "Option Agreements").

                  NOW, THEREFORE, in consideration of the promises and mutual
covenants contained herein, the parties hereto agree as follows:

                                   ARTICLE I.

                ISSUANCE AND PURCHASE OF COMMON STOCK AND OPTIONS

                  1.1 Sale of Common Stock; Issuance of Options. Subject to the
terms and conditions set forth herein, and simultaneously with the execution and
delivery of this Agreement, Issuer will sell to Investor and Investor will
purchase from Issuer for an aggregate purchase price of five million five
hundred thousand dollars ($5,500,000) (the "Purchase Price"), (i) five hundred
thousand (500,000) shares of Common Stock (the "Shares"), (ii) an option to
purchase six hundred twenty thousand (620,000) additional shares of Common Stock
at a price per share of ten dollars ($10.00) exercisable at any time prior to
6:00 p.m. on March 27, 2000 ("A Options") pursuant to the terms of the First
Option Agreement in the form attached hereto as Exhibit A (the "First Option
Agreement") and (iii) an option to purchase three hundred eighty thousand
(380,000) additional shares of Common Stock at a price per share of twelve
dollars ($12.00) exercisable at any time prior to 6:00 p.m. on March 27, 2000
("B Options") pursuant to the terms of the Second Option Agreement in the form
attached hereto as Exhibit B (the "Second Option Agreement") (the A Options and
the B Options are collectively referred to herein as the "Options" and the First




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Option Agreement and the Second Option Agreement are collectively referred to
herein as the "Option Agreements"). Pursuant to such purchase and sale, Investor
will pay, by wire transfer of immediately available funds to an account
designated in writing by the Issuer, the Purchase Price for all of the Shares
and Options and the Issuer will deliver to Investor certificates for the Shares
duly registered in the name of Investor or its designee and duly executed Option
Agreements.

                  1.2 Legend. Any certificate or certificates representing the
Shares and any Common Stock issued upon conversion or exercise of any Option
(the "Option Shares") shall bear the following legend:

                  THE SECURITIES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER
                  THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT") OR UNDER
                  ANY APPLICABLE STATE LAW AND MAY NOT BE TRANSFERRED, SOLD OR
                  OTHERWISE DISPOSED OF IN THE ABSENCE OF AN EFFECTIVE
                  REGISTRATION UNDER THE ACT OR AN OPINION OF COUNSEL REASONABLY
                  SATISFACTORY TO THE ISSUER THAT SUCH REGISTRATION IS NOT
                  REQUIRED UNDER THE ACT AND THE RULES AND REGULATIONS
                  PROMULGATED THEREUNDER OR UNDER APPLICABLE STATE SECURITIES
                  LAWS, AND FURTHER PROVIDED THAT SUCH TRANSFER IS EFFECTED IN
                  ACCORDANCE WITH THE PROVISIONS OF SECTION 5.2(b) OF THAT
                  CERTAIN STOCK PURCHASE AGREEMENT BY AND BETWEEN THE ISSUER AND
                  H. WAYNE HUIZENGA, DATED AS OF MARCH 28, 1995.

                                   ARTICLE II.

                                     CLOSING

                  The closing of the transactions contemplated herein (the
"Closing") shall occur concurrently with the execution and delivery of this
Agreement. At the Closing the following shall occur:

                               (i) Investor shall pay, by wire transfer of
                                    immediately available funds to an account
                                    designated in writing by Issuer, the
                                    Purchase Price set forth in Section 1.1;

                              (ii)  Issuer shall deliver to Investor the Shares,
                                    each duly registered in the name of
                                    Investor;



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                              (iii) Issuer and Investor shall each execute, and
                                    Issuer shall deliver to Investor, the Option
                                    Agreements attached hereto as Exhibits A and
                                    B; and

                               (iv) Investor shall deliver to Issuer a
                                    Certificate, in a form satisfactory to
                                    Issuer, of H. Wayne Huizenga certifying that
                                    Investor is not an Affiliate of WMX
                                    Technologies, Inc.

                                  ARTICLE III.

                  REPRESENTATIONS AND WARRANTIES OF THE ISSUER

                  Issuer represents and warrants to Investor (which
representations and warranties shall not be required or deemed to be updated or
made applicable to any time after the Closing Date) as follows:

                  3.1 Corporate Status. (a) The Issuer is a corporation duly
organized validly existing and in good standing under the laws of the State of
Ohio.

                  (b) The Issuer has all requisite corporate power and authority
to own or lease and operate its properties and to carry on its business as now
conducted.

                  (c) The Issuer is qualified to do business in all
jurisdictions where its ownership, lease or operation of property or the conduct
of its business requires such qualification, except where the failure to so
qualify would not have a Material Adverse Effect on the Issuer and its
Subsidiaries taken as a whole.

                  3.2 Power and Authority. The Issuer has the corporate power
and authority to execute and deliver, and to perform its obligations under this
Agreement and the Option Agreements and the transactions contemplated hereby and
thereby, and has taken all necessary corporate action to authorize the
execution, delivery and performance of this Agreement and the Option Agreements
and the transactions contemplated hereby and thereby.

                  3.3 Non-Contravention. None of the execution and delivery by
the Issuer of this Agreement or the Option Agreements, the consummation of the
transactions contemplated hereby or thereby, or the compliance by Issuer with
the terms and provisions hereof or thereof (including, without limitation, the
issuance to Investor by the Issuer of Shares as contemplated by and in
accordance with this Agreement and the issuance of the Option Shares as
contemplated by and in accordance with the Option Agreements), violates or will
violate the Amended and Restated Articles of Incorporation or Regulations of the
Issuer or any Requirement of Law applicable to the Issuer, conflicts with or
will conflict with or results or will result in any breach of any term,
condition or provision of, constitutes or will constitute (with due notice or
lapse of time or both) a default under, or results in the



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creation or imposition of any Lien upon any of the capital stock or properties
or assets of the Issuer pursuant to the terms of, any mortgage, deed of trust or
other material agreement or instrument to which the Issuer is a party or by
which it or any of its properties is bound, or results in the creation or
imposition of any Lien upon any of the capital stock or properties or assets of
the Issuer pursuant to the terms of any other agreement or instrument to which
the Issuer is a party or by which it or any of its properties is bound.

                  3.4 Consents/Approvals. (a) No consents, filings,
authorizations or other actions of any Governmental Authority are required for
the Issuer's execution, delivery and performance of this Agreement or the Option
Agreements.

                  (b) No consent, approval, waiver or other action by any Person
under any contract, agreement, indenture, lease, instrument or other document to
which the Issuer or any of its Subsidiaries is a party or by which any of them
is bound is required or necessary for the execution, delivery and performance by
the Issuer of this Agreement or the consummation of the transactions
contemplated hereby.

                  3.5 Enforceability. Each of this Agreement and the Option
Agreements have been duly executed and delivered by the Issuer and constitutes a
legal, valid and binding obligation of the Issuer enforceable against it in
accordance with its terms, except as the same may be limited by public policy
restrictions insofar as certain provisions herein concern rights of
indemnification and except as enforceability may be limited by applicable
bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the
enforcement of creditors' rights generally and general equitable principles.

                  3.6 Capitalization. The authorized capital stock of Issuer
consists of 52,000,000 shares, of which 50,000,000 are shares of Common Stock
and 2,000,000 are shares of preferred stock. As of the date hereof, 15,636,465
shares of Common Stock are validly issued and outstanding, fully paid, and
non-assessable, and no shares of preferred stock are issued or outstanding.
Except for 2,850,000 shares of Common Stock issuable pursuant to the OHM
Corporation 1986 Stock Option Plan, as amended (the "1986 Stock Option Plan"),
1,000,000 shares of Common Stock issuable pursuant to the OHM Corporation
Nonqualified Stock Option Plan for Directors (the "Directors' Option Plan"),
100,000 shares of Common Stock issuable pursuant to the Deferred Fee Plan for
Directors (the "Deferred Fee Plan") and 2,395,833 shares of Common Stock
issuable pursuant to conversion of the OHM 8% Convertible Subordinated
Debentures due 2006 (the "Convertible Debentures"), in each case issuable as of
the date hereof, and 10,368,000 shares of Common Stock issuable to Rust
International Inc. pursuant to the Rust Agreement, no other shares of Common
Stock or preferred stock or any rights, agreements, or commitments of any kind
obligating Issuer to issue or sell any other shares of Common Stock or preferred
stock are or will be outstanding or have been or will be authorized. Upon
delivery of the Shares and payment of the Purchase Price such Shares shall be
validly issued, fully paid and non-assessable shares of Common Stock.



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                  3.7 SEC Reports. The Annual Reports on Form 10-K for the year
ended December 31, 1993 and Quarterly Reports on Form 10-Q for the quarters
ended March 31, 1994, June 30, 1994 and September 30, 1994, of the Issuer filed
with the SEC under the Exchange Act, and all other reports and Proxy Statements
required to be filed by the Issuer, including, without limitation, a preliminary
proxy statement filed February 24, 1995 which includes financial statements for
the year ended December 31, 1994, have been duly and timely filed by the Issuer
(all such reports, collectively, the "SEC Reports"). The SEC Reports, when
filed, complied in all material respects with all applicable requirements of the
Exchange Act. None of the SEC Reports, at the time of filing, contained any
untrue statement of a material fact or omitted to state a material fact required
to be stated therein or necessary in order to make the statements therein not
misleading in light of the circumstances in which they were made. Issuer has
delivered to Investor true, accurate and complete copies of the SEC Reports, as
amended, and as in effect as of the date hereof.

                  3.8 Governing Documents. Issuer has delivered to Investor
true, accurate and complete copies of Issuer's Amended and Restated Articles of
Incorporation and Regulations in effect as of the date hereof.

                  3.9 Financial Statements. Each of the balance sheets included
in the SEC Reports (including any related notes and schedules) fairly presents
the consolidated financial position of the Issuer as of its date, and the other
financial statements included in the SEC Reports (including any related notes
and schedules) fairly present the consolidated results of operations or other
information included therein of Issuer for the periods or as of the dates
therein set forth in accordance with GAAP consistently applied during the
periods involved (except that the interim reports are subject to normal
recording adjustments which might be required as a result of year end audit and
do not contain all required footnote disclosures, and except as otherwise stated
therein).

                  3.10 Changes Since December 31, 1994. Since December 31, 1994
there has been no Material Adverse Change in the Issuer. There has not been any
direct or indirect redemption, purchase or other acquisition of any shares of
the Issuer's capital stock, or any declaration, setting aside or payment of any
dividend or other distribution by the Issuer in respect of its capital stock, or
any issuance of any shares of capital stock of Issuer or any granting to any
person of any option to purchase or other right to acquire shares of capital
stock of Issuer other than pursuant to the Rust Agreement or any employee or
director stock option, stock bonus plan or other employee or director benefit
plan.

                  3.11 Litigation. There is no suit, action, or legal,
administrative or other proceeding or governmental investigation pending, or to
the best of Issuer's knowledge, threatened, anticipated or contemplated against
Issuer or any of its properties, which, in any single case or in the aggregate,
challenge or question in any respect the validity of, or would prevent or hinder
the consummation of, the transactions contemplated by this Agreement.



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                                   ARTICLE IV.

                   REPRESENTATIONS AND WARRANTIES OF INVESTOR

                  Investor represents and warrants to the Issuer (which
representations and warranties shall not be required or deemed to be updated or
made applicable to any time after the Closing) as follows:

                  4.1 Power and Authority. The Investor is an individual
residing in the State of Florida with competence and authority to execute and
deliver, and to perform his obligations under this Agreement and the Option
Agreements and the transactions contemplated hereby and thereby, and has all
necessary authority to execute, deliver and perform this Agreement and the
Option Agreements and the transactions contemplated hereby and thereby.

                  4.2 Non-Contravention. None of the execution and delivery by
Investor of this Agreement or the Option Agreements, the consummation of the
transactions contemplated hereby or thereby, or the compliance by Investor with
the terms and provisions hereof or thereof, violates or will violate any
Requirement of Law applicable to Investor, conflicts with or will conflict with
or results or will result in any breach of any terms, condition nor provisions
of, constitutes or will constitute (with due notice or lapse of time or both) a
default under, any mortgage, deed of trust or other agreement or instrument to
which Investor is a party or by which he or any of his properties is bound,
other than such violations, conflicts, defaults or breaches which, individually
and in the aggregate, do not and will not materially and adversely impair
Investor's ability to perform his obligations hereunder or to consummate the
transactions contemplated hereby.

                  4.3 Consents/Approvals. (a) No consents, filings,
authorizations or actions of any Governmental Authority are required for
Investor's execution, delivery and performance of this Agreement or the Option
Agreement, other than compliance with any applicable requirements of the
Exchange Act.

                  (b) No consent, approval, waiver or other actions by any
person (other than any Government Authority referred to in Section 4.3(a) above)
under any contract, agreement, indenture, lease, instrument or other document to
which Investor is a party or by which he is bound is required or necessary for
the execution, delivery and performance by Investor of this Agreement or the
Option Agreements or the consummation of the transactions contemplated hereby or
thereby.

                  4.4 Enforceability. Each of this Agreement and the Option
Agreements have been duly executed and delivered by Investor and constitutes a
legal, valid and binding obligation of Investor enforceable against him in
accordance with its terms, except as enforceability may be limited by applicable
bankruptcy, insolvency, reorganization moratorium or similar laws affecting the
enforcement of creditor's rights generally and general equitable principles.



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                  4.5 Affiliate of WMX Technologies, Inc.. Investor is not an
Affiliate of WMX Technologies, Inc.

                  4.6 Investment Intent. Investor is acquiring the Shares and
Options hereunder for his own account and with no present intention of
distributing or selling such Shares, any interest in such Options or Option
Shares acquired upon exercise thereof in violation of the Securities Act or any
applicable state securities law. Investor agrees that he will not sell or
otherwise dispose of any of the Shares, any interest in such Options or Option
Shares acquired upon exercise thereof unless such sale or other disposition has
been registered under the Securities Act or, in the opinion of counsel
reasonably satisfactory to the Issuer, is exempt from registration under the
Securities Act and has been registered or qualified or, in the opinion of such
counsel, is exempt from registration or qualification under applicable state
securities laws. Investor understands that the sale of the Shares being acquired
by him hereunder and the related acquisitions of securities of the Issuer upon
Investor's entry into the Option Agreements and any issuance of Option Shares
upon exercise by Investor thereof have not been registered under the Securities
Act by reason of their contemplated issuance in transactions exempt from the
registration and prospectus delivery requirements of the Securities Act pursuant
to Section 4(2) thereof, and that the reliance of the Issuer on such exemption
from registration is predicated in part on these representations and warranties
of Investor. Investor acknowledges that pursuant to Section 1.2 a restrictive
legend consistent with the foregoing has been or will be placed on the
certificates for the Shares, on the Option Agreements and on certificates for
any Option Shares issued upon exercise thereof and related stop transfer
instructions will be noted in the transfer records of the Issuer and/or its
transfer agent for the shares of Issuer's Common Stock. Issuer acknowledges
that, with respect to the requirement of counsel reasonably satisfactory to
Issuer contemplated by this Section and the Legend set forth in Section 1.2
hereof, the law firm of Akerman, Senterfitt & Eidson, P.A., Miami, Florida, is
such reasonably satisfactory counsel.

                  4.7 Investor Knowledge. Investor is an accredited investor as
such term is defined in Rule 501 of the General Rules and Regulations under the
Securities Act, and, either alone or with his financial advisor(s), has such
knowledge and experience in financial and business matters that he is capable of
evaluating the merits and risks of the investment to be made by him hereunder.
Investor acknowledges that no representations or warranties of any type or
description have been made to him by any Person with regard to the Issuer, any
of its Subsidiaries, any of their respective businesses, properties or prospects
or the investment contemplated herein, other than the representations and
warranties set forth in Article III hereof.

                  4.8 No Commissions. Investor has not incurred any obligation
for any finder's or broker's or agent's fees or commissions in connection with
the transactions contemplated hereby.



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                                   ARTICLE V.

                                    COVENANTS

                  5.1 Covenants of the Issuer and the Investor. (a) Filings.
Each of Investor and Issuer shall make on a prompt and timely basis all
governmental or regulatory notifications and filings required to be made by it
for the consummation of the transactions contemplated hereby.

                  (b) Public Announcements. Except as required by Law or the
policies or rules of any stock exchange (or the NASDAQ-NMS) on which the
Issuer's securities are listed as of the date hereof, the form and content of
all press releases or other public communications of any sort relating to the
subject matter of this Agreement or the Option Agreements, and the method of
their release, or publication thereof, shall be subject to the prior approval of
the parties hereto, which approval shall not be unreasonably withheld or
delayed.

                  (c) Further Assurances. Each party shall execute and deliver
such additional instruments and other documents and shall take such further
actions as may be necessary or appropriate to effectuate, carry out and comply
with all of the terms of this Agreement and the Option Agreements and the
transactions contemplated hereby and thereby.

                  (d) Cooperation. The Issuer and Investor each agree to
cooperate with the other in the preparation and filing of all forms,
notifications, reports and information, if any, required or reasonably deemed
advisable pursuant to any Requirement of Law or the rules of any exchange on
which the Common Stock is traded or the NASDAQ-NMS in connection with the
transactions contemplated by this Agreement and the Option Agreements and to use
their respective reasonable best efforts jointly to agree on a method to
overcome any objections by any Governmental Authority to any such transactions.
Except as may be specifically required hereunder, neither of the parties hereto
or their respective Affiliates shall be required to agree to take any action
that in the reasonable opinion of such party would result in or produce a
Material Adverse Effect.

                  5.2 Additional Covenant of Investors. (a) Investor represents,
warrants, covenants and agrees that (i) he will provide to the Issuer for
inclusion in the Issuer's Proxy Statement for the 1995 Annual Meeting of
Shareholders (the "Proxy Statement") all information concerning Investor and his
Affiliates requested by Issuer and necessary for the preparation of the Proxy
Statement and (ii) such information will not contain any material misstatement
of fact or omit to state any material fact necessary to make the statements, in
light of the circumstances under which they are made, not misleading.

                  (b) Investor agrees, except as otherwise required by law or
regulatory directive, not to sell or otherwise transfer or dispose of all or any
portion of his interest in the Option Agreements during the Holding Period.
Investor agrees, except as otherwise required by law or regulatory directive,
not to sell or otherwise dispose of any of the Shares



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or any of the Option Shares and directly or indirectly held by Investor during
the Holding Period. Notwithstanding anything in this Section 5.2 to the
contrary, Investor may make any such sale, transfer or disposition to an
Affiliate of Investor which agrees to be bound by the provisions contained in
this Section; provided that such Affiliate holding such Shares and/or Option
Shares is prevented (in a manner reasonably satisfactory to the Issuer) from
transferring such Shares and/or Option Shares, by dividend, distribution or
otherwise, to any entity that is not an Affiliate of Investor, until the end of
the Holding Period. Any such agreement of Affiliates of Investor shall be in
writing in a form reasonably satisfactory to the Issuer. The Issuer may impose
stop-transfer instructions with respect to the Shares and/or Option Shares
subject to the foregoing restrictions set forth above until the end of the
Holding Period.

                                   ARTICLE VI.

                                   DEFINITIONS

                  6.1 Defined Terms. As used herein the following terms shall
have the following meanings:

                  "Affiliate" shall have the meaning ascribed to it in Rule
12b-2 of the General Rules and Regulations under the Exchange Act, as in effect
on the date hereof.

                  "Articles of Incorporation" means the Issuer's Articles of
Incorporation, as the same may be supplemented, amended or restated from time to
time.

                  "Closing" has the meaning specified in ARTICLE II of this
Agreement.

                  "Common Stock" has the meaning specified in the Recitals to
this Agreement.

                  "Cutback Registration" means any registration in which the
managing underwriter advises the Issuer that marketing factors require a
limitation of the number of shares of Common Stock to be underwritten in such
registration.

                  "Electing Holder" means any holder of Common Stock, other than
holders of Registrable Securities (in their respective capacities as such), who
has the right to request inclusion of Common Stock held by such holder in a
registration;

                  "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

                  "GAAP" means generally accepted accounting principles in
effect in the United States of America from time to time.



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                  "Governmental Authority" means any nation or government, any
state or other political subdivision thereof, and any entity or official
exercising executive, legislative, judicial, regulatory or administrative
functions of or pertaining to government.

                  "Holding Period" means the period of time during which
Investor may not transfer any portion of his interest in the Shares the Option
Agreements or the Option Shares commencing as of the date of Closing and ending
upon the earliest to occur of (i) consummation of the transactions contemplated
by the Rust Agreement, (ii) termination of the Rust Agreement, or (iii)
September 30, 1995.

                  "Issuer" means OHM Corporation, an Ohio corporation.

                  "Law" means any domestic or foreign, federal, state or local
law, statute, ordinance, rule or regulation.

                  "Lien" means any mortgage, pledge, security interest,
encumbrance, lien or charge of any kind (including any conditional sale or other
title retention agreement, any lease in the nature thereof, and the filing of or
agreement to give any financing statement under the Uniform Commercial Code or
comparable law or any jurisdiction in connection with such mortgage, pledge,
security interest, encumbrance, lien or charge).

                  "Material Adverse Change (or Effect)" means a change (or
effect), in the financial condition or results of operations which change
individually or in the aggregate, is materially adverse to such financial
condition or results of operations.

                  "Option Agreements" has the meaning specified in Section 1.1
of this Agreement.

                  "Option Shares" has the meaning specified in Section 1.2 of
this Agreement.

                  "Person" means an individual, partnership, corporation,
business trust, joint stock company, trust, unincorporated association, joint
venture, Governmental Authority or other entity, of whatever nature.

                  "Piggyback Registration" has the meaning specified in Section
7.1(a) of this Agreement.

                  "Purchase Price" has the meaning specified in Section 1.1 of
this Agreement.

                  "Register", "registered" and "registration" refer to a
registration of the offering and sale of Common Stock effected by preparing and
filing a registration statement in compliance with the Securities Act and the
declaration or ordering of the effectiveness of such registration statement.



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                  "Registrable Securities" means any of the Shares, any of the
Option Shares, any shares of Common Stock sold by the Issuer pursuant to that
certain Stock Purchase Agreement, dated even date herewith, between the Issuer
and the Huizenga Family Foundation, Inc. (the "Other Shares") and any other
shares of Common Stock or other securities issued in respect of the Shares or
Option Shares or Other Shares by way of stock dividend or stock split or in
connection with any recapitalization, merger, consolidation or reorganization;
provided that, as to any particular securities, such securities will cease to be
Registrable Securities when (i) they have been sold pursuant to registration or
pursuant to Rule 144 promulgated by the Securities and Exchange Commission or
any similar rule then in force ("Rule 144") or (ii) there has occurred a
transfer or assignment in respect of such Shares in violation of either of
Section 5.2(b) hereof.

                  "Requirement of Law" means as to any Person, the articles of
incorporation, by-laws or other organizational or governing documents of such
person, and any Law, or determination of any arbitrator or a court or other
Governmental Authority, in each case applicable to or binding upon such Person
or any of its properties or to which such Person or any of its property is
subject.

                  "Rust Agreement" means that Agreement and Plan of
Reorganization dated as of December 5, 1994 among the Issuer, Rust Remedial
Services Inc., Enclean Environmental Services Group, Inc., Rust Environmental,
Inc. and Rust International Inc., as the same may be supplemented, amended or
modified from time to time.

                  "SEC" means the Securities and Exchange Commission.

                  "SEC Reports" has the meaning specified in Section 3.7 of this
Agreement.

                  "Securities Act" means the Securities Act of 1933, as amended.

                  "Shares" has the meaning specified in Section 1.1 of this
Agreement.

                  "Subsidiary" means as to any Person, a corporation of which
more than 50% of the outstanding capital stock having full voting power is at
the time directly or indirectly owned or controlled by such Person.

         6.2      Other Definitional Provisions.

                  (a) All terms defined in this Agreement shall have the defined
meanings when used in any certificate, report or other documents made or
delivered pursuant hereto or thereto, unless the context otherwise requires.

                  (b) Terms defined in the singular shall have a comparable
meaning when used in the plural, and vice versa.



                                       11


   15



                  (c) All matters of an accounting nature in connection with
this Agreement and the transactions contemplated hereby shall be determined in
accordance with GAAP applied on a basis consistent with prior periods, where
applicable.

                  (d) As used herein, the neuter gender shall also denote the
masculine and feminine, and the masculine gender shall also denote the neuter
and feminine, where the context so permits.

                  (e) The words "hereof", "herein" and "hereunder", and words of
similar import, when used in this Agreement shall refer to this Agreement as a
whole and not to any particular provision of this Agreement.

                                  ARTICLE VII.

                               REGISTRATION RIGHTS

                  Investor shall have the following registration rights with
respect to the Shares and the Option Shares.

                  7.1 Transfer of Registration Rights. Investor may assign the
registration rights with respect to the Shares and the Option Shares to any
Affiliate as well as any party or parties to which it may from time to time
transfer the Shares or Option Shares; except that Investor may transfer the
demand registration rights discussed in Section 7.3 hereof only to subsequent
holders of at least two hundred fifty thousand (250,000) Shares or Option Shares
after giving effect to the transfer of any Shares or Option Shares in connection
therewith. Upon assignment of any registration rights pursuant to this Section
7.1, Investor shall deliver to Issuer a notice of such assignment which includes
the identity and address of any assignee (collectively, Investor and each such
subsequent holder is referred to as a "Holder").

                  7.2 Piggyback Registration.

                  (a) From and after the Holding Period, if at any time, and
from time to time, the Issuer proposes to effect a registration for its account
or for the account of a security holder or holders (other than a registration on
Form S-8, or any similar or successor form thereto, relating to an employee or
director stock option, stock purchase or other benefit plan, or a registration
relating to shares issuable in a merger, consolidation, exchange offer, purchase
of assets or any similar transaction) ("Piggyback Registration"), the Issuer
shall:

                           (i) promptly give to each Holder of Registrable
                  Securities written notice thereof (which written notice shall
                  include a list of the jurisdictions in which the Issuer
                  intends to attempt to qualify such securities under or



                                       12


   16



                  otherwise comply with the applicable blue sky or other state
                  securities laws); and

                           (ii) include in such registration (and any related
                  qualification under or other compliance with blue sky or other
                  state securities laws), and in any underwriting involved
                  therein on the same terms and conditions as the securities
                  being issued thereunder, all the Registrable Securities
                  specified in a written request, made within 15 days after
                  receipt of such written notice from the Issuer, by any holder
                  of Registrable Securities; provided that if such registration
                  is a Cutback Registration, then (i) if such registration is a
                  primary registration, whether or not it includes a secondary
                  registration, on behalf of the Issuer, the Issuer shall
                  register in such registration (A) first, the shares of Common
                  Stock the Issuer proposes to sell in such registration, and
                  (B) second, shares of Common Stock held by each holder of
                  Registrable Securities and the Electing Holders on a pro rata
                  basis, based upon the number of shares of Common Stock the
                  holders of Registrable Securities and any Electing Holders
                  originally sought to include in such registration; and (ii) if
                  such registration is a Piggyback Registration which is solely
                  a secondary registration on behalf of holders of Common Stock,
                  the Issuer shall register in such registration shares of
                  Common Stock held by each holder of Registrable Securities and
                  the Electing Holders on a pro rata basis, based upon the
                  number of shares of Common Stock the holders of Registrable
                  Securities and any Electing Holders originally sought to
                  include in such registration and provided, further, that if
                  such registration is a Cutback Registration, the Issuer shall
                  use its best efforts to include all shares of Registrable
                  Securities specified in the Holder's written request, but such
                  best efforts shall not include an obligation on the part of
                  the Issuer to reduce the number of shares of the Issuer or the
                  other Electing Holders included in such Cutback Registration
                  beyond that expressly provided for in this Section.

                  (b) If the registration of which the Issuer gives notice is
pursuant to an effective registration statement under the Securities Act
involving an underwriting, the Issuer shall so advise each Holder as part of the
written notice given pursuant to subclause (i) above. In such event, the right
of each such Holder to registration pursuant to this Section shall be
conditioned upon such Holder's participation in such underwriting, the inclusion
of the Registrable Securities in the underwriting and such Holder entering into
an underwriting agreement, containing customary terms and conditions in a form
reasonably acceptable to the Holder and the Issuer, with the underwriter or
underwriters selected for such underwriting by the Issuer; provided that if such
underwriting agreement shall not be acceptable to Holder and after reasonable
efforts by Issuer cannot be made acceptable to Holder, the Issuer may proceed
with such registration without registering the stock of Holder in such
registration.

                  7.3 Holder Requested Registration. (a) Subject to the
limitations contained in Section 7.1 and paragraph (c) of this Section 7.3,
Holder shall have the right to require the Issuer to effect any registration
with respect to the Registrable Securities held by Holder.



                                       13


   17



Upon receipt of a request for registration from Holder, the Issuer shall as soon
as practicable, use its best efforts to effect such registration, including
without limitation, the execution of an undertaking to file post-effective
amendments, appropriate qualification under applicable blue sky or other state
securities laws in accordance with Section 7.4(a)(v) hereof and appropriate
compliance with applicable regulation issued under the Securities Act as may be
so requested and as would permit or facilitate the sale and distribution of all
or such portion of such Registrable Securities as are specified in such request;
provided that the Issuer shall not be obligated to take any action to effect any
such registration, qualification or compliance pursuant to this Section 7.3
within 120 days immediately following the effective date of any registration
statement pertaining to an underwritten public offering of securities of the
Issuer for its own account, unless the Holder shall have elected to include
Registrable Securities in such registration statement pursuant to Section 7.2
hereof and all of such Registrable Securities which Holder elected to include in
such registration statement were not so included as a result of the provisions
of Section 7.2(a)(ii) hereof. Holder shall have the right to designate the
managing underwriter for any registration under this Section 7.3, which
underwriter shall be reasonably acceptable to Issuer.

                  (b) The Issuer shall file a registration statement covering
the Registrable Securities so requested to be registered as soon as practicable
after receipt of the request of Holder, but in no event sooner than thirty days
thereafter.

                  (c) Holders of Registrable Securities shall be entitled to an
aggregate of 3 demand registrations and each such demand registration shall
include at least 250,000 Registrable Securities.

                  (d) The Issuer shall not be required to effect a registration
at a time when audited financial statements are not available or when the Issuer
is in possession of material information which, in the exercise of its
reasonable judgment, the Issuer deems advisable not to disclose in a
registration statement, however, the Issuer may only postpone a registration for
such reasons, in each case, for up to 60 days and not more than once during any
three month period.

                  (e) If Holder intends to distribute the Registrable Securities
covered by its request by means of an underwriting, it shall so advise the
Issuer as part of its request made pursuant to this Section. Holder shall enter
into an underwriting agreement, including best efforts or continuous offering
underwriting, in a form which is reasonably satisfactory to Holder with the
underwriter or underwriters selected for such underwriting by Holder and which
are reasonably satisfactory to the Issuer. The Issuer shall sign an agreement
with such underwriters confirming for the benefit of the underwriters its
indemnity obligations under this Agreement. The Issuer may include securities
for its own account in such registration if the underwriter so agrees and if the
number of Registrable Securities which would otherwise have been included in
such registration and underwriting would not thereby be limited.



                                       14


   18



                  (f) In the event more than one Person is a Holder of
Registrable Securities, the rights of the Holder under this Section 7.3 may be
exercised only upon election of Investor or such Holders of more than 51% of the
Registrable Securities collectively.

                  7.4 Registration Procedures. (a) In case of each registration,
qualification or compliance effected by the Issuer subject to this Article VII,
the Issuer shall keep Holder advised in writing as to the initiation of each
such registration, qualification and compliance and as to the completion
thereof. In addition, at its expense, the Issuer shall:

                                 (i) before filing a registration statement or
                  prospectus or any amendment or supplements thereto subject to
                  this Article VII, the Issuer shall furnish to counsel selected
                  by Holder copies of all such documents proposed to be filed
                  and the portions of such documents provided in writing by
                  Holder for use therein and for which Holder shall indemnify
                  the Issuer shall be subject to such Holders approval;

                                (ii) prepare and file with the SEC such
                  amendments and supplements to such registration statement as
                  may be necessary to keep such registration, qualification or
                  compliance effective for a period of up to 120 days or until
                  Holder has completed the distribution described in the
                  registration statement relating thereto, whichever first
                  occurs and comply with provisions of the Securities Act with
                  respect to the disposition of all securities covered thereby
                  during such period;

                               (iii) update, correct, amend and supplement such
                  registration, qualification or compliance as necessary;

                               (iv) if such offering is to be underwritten, in
                  whole or in part, enter into a written underwriting agreement
                  containing customary terms and conditions and in form and
                  substance reasonably satisfactory to the managing underwriter
                  and the registering Holder;

                               (v) furnish such number of prospectuses,
                  including preliminary prospectuses, and other documents
                  incident thereto as Holder may reasonably request from time to
                  time, which shall be a Selling Expense;

                               (vi) register or qualify such Registrable
                  Securities under such other securities or blue sky laws of
                  such jurisdictions of the United States (up to five of which
                  shall be at the expense of the Issuer, and any additional of
                  which shall be at the expense of Holder) as Holder may deem
                  reasonable to enable it to consummate the disposition in such
                  jurisdiction of the Registrable Securities (provided that
                  Issuer will not be required to (i) qualify generally to do
                  business in any jurisdiction where it would not otherwise be
                  required to qualify but for this section, or (ii) consent to
                  general service of process in any such jurisdiction);



                                       15


   19




                               (vii) notify Holder at any time when a prospectus
                  relating to the Registrable Securities is required to be
                  delivered under the Securities Act, of the happening of any
                  event as a result of which the prospectus included in such
                  registration statement contains an untrue statement of a
                  material fact or omits any fact necessary to make the
                  statement therein not misleading, and at the request of
                  Holder, Issuer will prepare a supplement or amendment to such
                  prospectus so that, as thereafter delivered to the purchasers
                  of such shares, such prospectus will not contain any untrue
                  statements of a material fact or omit to state any fact
                  necessary to make the statements therein not misleading;

                               (viii) cause all such Registrable Securities to
                  be listed on each securities exchange on which similar
                  securities issued by Issuer are then listed;

                               (ix) provide a transfer agent and registrar for
                  all such Registrable Securities not later than the effective
                  date of such registration statement;

                               (x) upon the sale of any Registrable Securities
                  pursuant to such registration statement, remove all
                  restrictive legends from all certificates or other instruments
                  evidencing the Registrable Securities;

                                (xi) furnish, at the request of Holder, on the
                  date that such Registrable Securities are delivered to the
                  underwriter for sale in connection with a registration
                  pursuant to this section, if such Registrable Securities are
                  being sold through an underwriter, or if such Registrable
                  Securities are not being sold through an underwriter, on the
                  date that the registration statement with respect to such
                  Registrable Securities becomes effective, (i) an opinion dated
                  such date of the counsel representing Issuer for purpose of
                  such registration, in form and substance as is customarily
                  given to underwriters in an underwritten public offering,
                  addressed to such underwriter, if any, and to Holder; and (ii)
                  a letter dated as of such date from the independent certified
                  public accountant of Issuer, in form and substance as is
                  customarily given by independent certified public accountants
                  to underwriters in connection with a public offering,
                  addressed to the underwriter, if any, and to Holder; and

                               (xii) make available for inspection by Holder,
                  any underwriter participating in any disposition pursuant to
                  such registration statement, and any attorney, accountant or
                  any other agent retained by Holder or such underwriter, all
                  financial and other records, pertinent corporate documents and
                  properties of Issuer, and cause Issuer's officers, directors
                  and employees to supply all information reasonably requested
                  by any such Holder, underwriter, attorney, accountant or agent
                  in connection with such registration statement.

                  (b) Except as required by law, all expenses incurred by the
Issuer in complying with this Article VII, including but not limited to, all
registration, qualification



                                       16


   20



and filing fees, printing expenses, fees and disbursements of counsel for the
Issuer, blue sky fees and expenses in accordance with Section 7.4(A)(v) hereof,
including fees and disbursements of counsel related to all blue sky matters, but
excluding the compensation of regular employees of the Issuer which shall be
paid in any event by the Issuer ("Registration Expenses") incurred in connection
with any registration, qualification or compliance pursuant to such Sections
shall be borne by the Issuer. All underwriting discounts and selling commissions
applicable to a sale ("Selling Expenses") incurred in connection with any
registration of Registrable Securities and the legal fees of Holder shall be
born by Holder.

                  7.5 Further Information. If Registrable Securities owned by a
Holder are included in any registration, such Holder shall furnish the Issuer
such information regarding itself and the distribution proposed by such Holder
as the Issuer may reasonably request and as shall be required in connection with
any registration, qualification or compliance referred to in this Agreement.

                  7.6 Registration During Holding Period. Issuer agrees not to
register, prior to the expiration of the Holding Period, any shares of Common
Stock under the Securities Act to which Investor's registration rights
contemplated by Section 7.2 hereof would apply unless provision is made to allow
Holder to exercise the registration rights provided for under Section 7.2
notwithstanding any requirements under the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended.

                                  ARTICLE VIII.

                                 INDEMNIFICATION

                  8.1 Indemnification Relating to Registration Rights. (a) With
respect to any registration, qualification or compliance effected or to be
effected pursuant to Article VII of this Agreement, the Issuer shall indemnify
each holder of Registrable Securities whose securities are included or are to be
included therein, each of such holder's directors and officers, each underwriter
(as defined in the Securities Act) of the securities sold by such holder, and
each Person who controls (within the meaning of the Securities Act) any such
holder or underwriter (a "Controlling Person") from and against all losses,
damages and liabilities (or actions in respect thereof) arising out of or based
on any claim, cause of action, proceeding or litigation asserted or commenced or
threatened against any such holder or any of its officers and directors or any
such underwriter or Controlling Person concerning:

                    (i) any untrue statement (or alleged untrue statement) of a
         material fact contained in any prospectus, offering circular or other
         document (including any related registration statement, notification or
         the like) incident to any such registration, qualification or
         compliance;



                                       17


   21



                   (ii) any omission (or alleged omission) to state therein a
         material fact required to be stated therein or necessary to make the
         statement therein, in the light of the circumstances under which it was
         made, not misleading; or

                  (iii) any violation by the Issuer of the Securities Act or any
         rule or regulation promulgated thereunder applicable to the Issuer, or
         of any blue sky or other state securities laws or any rule or
         regulation promulgated thereunder applicable to the Issuer,

in each case, relating to action or inaction required of the Issuer in
connection with any such registration, qualification or compliance, and subject
to Section 8.2 below will reimburse each such Person entitled to indemnity under
this Section 8.1 for all legal and other expenses incurred in connection with
investigating or defending any such claim, loss damage, liability or action;
provided, however, that, the foregoing indemnity and reimbursement obligation
shall not be applicable to the extent that any such claim, loss, damage or
liability arises out of or is based on any untrue statement (or alleged untrue
statement) or omission (or alleged omission) made in reliance upon and in
conformity with written information furnished to the Issuer by or on behalf of
such a holder or by or on behalf of such an underwriter specifically for use in
such prospectus, offering circular or other document; provided, further,
however, that, with respect to any untrue statement (or alleged untrue
statement) or omission (or alleged omission) made in any preliminary prospectus,
the indemnity agreement contained in this Section shall not inure to the benefit
of any underwriter, or, if there shall be no such underwriter, other person
participating in such sale who is obligated under the Securities Act to deliver
a prospectus ("Delivering Person"), to the extent that any such losses claims,
damages or liabilities of such underwriter or Delivering Person, as the case may
be, result from the fact that there was not delivered to any Person who
purchased Registrable Securities a copy of the final prospectus relating to such
registration, as then amended or supplemented (exclusive of material
incorporated by reference) at or prior to the written confirmation of the sale
of such Registrable Securities to such Person), if (A) such delivery was
required by the Securities Act, (B) the untrue statement (or alleged untrue
statement) or omission (or alleged omission) made in such preliminary prospectus
was corrected in such final prospectus, and (C) the Issuer had previously and
timely furnished copies thereof to such underwriter or Delivering Person, as the
case may be.

                  (b) With respect to any registration, qualification or
compliance effected or to be effected pursuant to this Agreement, each holder of
Registrable Securities whose securities are included or are to be included
therein, shall indemnify the Issuer, its directors and officers, and, if and to
the extent required by the underwriters of an underwritten offering in which
such holder will be selling Registrable Securities, each underwriter (as defined
in the Securities Act) of the securities sold by such holder and each Person who
controls (within the meaning of the Securities Act) the Issuer or any such
underwriter (a "Controller") from and against all losses, damages and
liabilities (or actions in respect thereof) arising out of or based on any
claim, cause of action, proceeding or litigation asserted or commenced against
the Issuer or any of its directors and officers or any such underwriter or
Controller concerning:



                                       18


   22




                    (i) any untrue statement (or alleged untrue statement) of a
         material fact contained in any prospectus, offering circular or other
         document (including any related registration statement, notification or
         the like) incident to any such registration, qualification or
         compliance;

                   (ii) any omission (or alleged omission) to state therein a
         material fact required to be stated therein or necessary to make the
         statement therein, in the light of the circumstances under which it was
         made, not misleading; or

                  (iii) any violation by such holder of the Securities Act or
         any rule or regulation promulgated thereunder applicable to the Issuer
         or such holder or of any blue sky or other state securities laws or any
         rule or regulation promulgated thereunder applicable to the Issuer or
         such holder,

in each case, relating to action or inaction required of such holder in
connection with any such registration, qualification or compliance, and subject
to Section 8.2 below will reimburse each such Person entitled to indemnity under
this Section for all legal and other expenses reasonably incurred in connection
with investigating or defending any such claim, loss, damage, liability or
action; provided, however, that, the foregoing indemnity and reimbursement
obligation shall only be applicable to the extent that any such claim, loss,
damage or liability arises out of or is based on any untrue statement (or
alleged untrue statement) or omission (or alleged omission) made in reliance
upon and in conformity with written information furnished to the Issuer by or on
behalf of the holder specifically for use in such prospectus, offering circular
or other document; provided, however, that the obligations of the holder
hereunder shall be limited to an amount equal to the proceeds to the holder of
Registrable Shares sold as contemplated hereunder.

                  8.2 Indemnification Procedures. Each Person entitled to
indemnification under this Section (an "Indemnified Party") shall give notice as
promptly as reasonably practicable to each party required to provide
indemnification under this Section (an "Indemnifying Party") of any action
commenced against it in respect of which indemnity may be sought hereunder, but
failure so to notify an Indemnifying Party shall not relieve such Indemnifying
Party from any liability that it may have otherwise than on account of this
indemnity agreement so long as such failure shall not have materially prejudiced
the position of the Indemnifying Party. Upon such notification, the Indemnifying
Party shall assume the defense of such action and after such assumption the
Indemnifying Party shall not be entitled to reimbursement of any expenses
incurred by it in connection with such action except as described below. In any
such action, any Indemnified Party shall have the right to retain its own
counsel, but the fees and expenses of such counsel shall be at the expense of
such Indemnified Party unless (i) the Indemnifying Party and the Indemnified
Party shall have mutually agreed to the contrary or (ii) the named parties in
any such action (including any impleaded parties) include both the Indemnifying
Party and the Indemnified Party and representation of both parties by the same
counsel would be inappropriate due to actual or potential differing interests
between them. It is understood that the Indemnifying Party shall not, in
connection with any action in the same jurisdiction be liable for the fees and
expenses



                                       19


   23



of more than one separate firm for all Indemnified Parties in addition to any
firm(s) which the Indemnifying Party may retain to represent it. The
Indemnifying Party shall not be liable for any settlement of any proceeding
effected without its written consent (which shall not be unreasonably withheld
or delayed by such Indemnifying Party), but if settled with such consent or if
there be final judgment for the plaintiff, the Indemnifying Party shall
indemnify the Indemnified Party from and against any loss, damage or liability
by reason of such settlement or judgment.

                                   ARTICLE IX.

                                  MISCELLANEOUS

                  9.1 Notices. All notices, requests, demands, claims, and other
communications hereunder shall be in writing and shall be delivered by certified
or registered mail (first class postage pre-paid), guaranteed overnight
delivery, or facsimile transmission if such transmission is confirmed by
delivery by certified or registered mail (first class postage pre-paid) or
guaranteed overnight delivery:

                  (a)      if to Issuer to:

                           OHM Corporation
                           16406 U.S. Route 224 East
                           Findlay, Ohio 45840
                           Attention: General Counsel

                           Telecopy: (419) 424-4985

                           with a copy to:
                           Jones, Day, Reavis & Pogue
                           41 South High Street
                           1900 Huntington Center
                           Columbus, OH  43215
                           Attention:  Robert J. Gilker, Esq.

                           Telecopy:  (614) 469-4198

                  (b)      if to Investor to:

                           H. Wayne Huizenga
                           200 South Andrews Avenue
                           Fort Lauderdale, Florida 33301
                           Attention:  Richard C. Rochon

                           Telecopy: (305) 523-0801



                                       20


   24



                           with a copy to:
                           Akerman, Senterfitt & Edison, P.A.
                           24th Floor, One Brickell Square
                           801 Brickell Avenue
                           Miami, FL  33131
                           Attention:  Stephen K. Roddenberry, Esq.

                           Telecopy:  (305) 374-5095

                  (c) or, in each case, at such other address or to such other
person as may be specified in writing to the other party.

                  9.2 Non-Waiver of Remedies and Actions. No course of dealing
between the Issuer and Investor with respect to any Common Stock, or any delay
on the part of either such party in exercising any rights available to such
party shall operate as a waiver of any right of such party, except to the extent
expressly waived in writing by such party.

                  9.3 Headings. The headings in this Agreement are for purposes
of reference only and shall not be considered in construing this Agreement.

                  9.4 Counterparts. This Agreement may be executed in any number
of counterparts, each of which when so executed and delivered shall constitute
an original and all together shall constitute one Agreement.

                  9.5 Successors and Assigns. Except as otherwise specifically
provided herein, this Agreement shall bind and inure to the benefit of the
Issuer's and Investor's respective successors and permitted assigns; provided
that neither the Issuer nor Investor shall have any right to assign any of its
rights hereunder except as otherwise specifically provided for herein, or any
interest herein without obtaining the written consent of the other to such
assignment, and any purported assignment made without obtaining such written
consent shall be null and void. Notwithstanding the foregoing, any Person who is
a holder of shares of Common Stock shall have all rights and benefits afforded
to such holder, in its capacity as such, pursuant and subject to the terms of
the Article of Incorporation.

                  9.6 Survival. Notwithstanding any investigation made by
Investor, all covenants, agreements, representations and warranties made herein
and in certificates delivered pursuant hereto shall survive the delivery to
Investor of the Common Stock to be purchased pursuant to Section 1.1.

                  9.7 Enforceability. If any term or provision of this
Agreement, or the application thereof to any Person or circumstance, shall, to
any extent, be invalid or unenforceable, the remaining terms and provisions of
this Agreement or application to other Persons and circumstances shall not be
invalidated thereby, and each term and provision hereof shall be construed with
all other remaining terms and provisions hereof to effect the intent of the
parties hereto to the fullest extent permitted by law.



                                       21


   25




                  9.8 Law Governing. This Agreement shall be construed and
enforced in accordance with and shall be governed by the laws of the State of
Ohio applicable to contracts executed by residents of that state, and fully to
be performed, in that state.

                  9.9 Severability. In the event that any provision of this
Agreement is deemed invalid, illegal or unenforceable, the validity, legality
and enforceability of the remaining provisions shall not in any way be affected
or impaired thereby.

                  9.10 Remedies. (a) Each of Investor and Issuer acknowledges
that the other party would not have an adequate remedy at law for money damages
in the event that any of the covenants or agreements of such party in this
Agreement was not performed in accordance with its terms, and it is therefore
agreed that each of Investor and Issuer in addition to and without limiting any
other remedy or right such party may have, shall have the right to an injunction
or other equitable relief in any court of competent jurisdiction, enjoining any
such breach and enforcing specifically the terms and provisions hereof, and each
of Investor and Issuer hereby waive any and all defenses such party may have on
the ground of lack of jurisdiction or competence of the court to grant such an
injunction or other equitable relief.

                  (b) All rights, powers and remedies provided under this
Agreement or otherwise available in respect hereof at law or in equity shall be
cumulative and not alternative, and the exercise or beginning of the exercise of
any thereof by any party shall not preclude the simultaneous or later exercise
of any other such right, power or remedy by such party.

                  9.11 Expenses. Except as otherwise expressly provided herein,
each party hereto shall bear its own expenses incurred in connection with the
negotiation, execution and performance of this Agreement.

                  9.12 Entire Agreement. This Agreement and the Option
Agreements constitute the entire understanding of the parties with respect to
the subject matter hereof and superseded all prior discussions, agreements and
representations, whether oral or written, concerning the subject matter hereof.



                                       22


   26



                  IN WITNESS WHEREOF, the parties hereto have caused this Stock
Purchase Agreement to be duly executed and delivered as of the day and year
first above written.

                           OHM CORPORATION

                           By: /s/ RANDALL M. WALTERS
                              --------------------------------------------------
                           Name: Randall M. Walters
                           Title:  Vice President, General Counsel and Secretary

                           /s/ H. WAYNE HUIZENGA
                              --------------------------------------------------
                           H. Wayne Huizenga



                                       23
   27


================================================================================
- --------------------------------------------------------------------------------
                                                                               
  
                                                                      EXHIBIT A









                             FIRST OPTION AGREEMENT

                                 by and between

                                H. WAYNE HUIZENGA

                                       and

                                 OHM CORPORATION

                           Dated as of March 28, 1995




- --------------------------------------------------------------------------------
================================================================================







   28

                                


                                TABLE OF CONTENTS



                                                                                                                PAGE 
                                                                                                                ----
                                                                                                             
         1.  GRANT OF OPTION....................................................................................  2 

                  1.1  Grant....................................................................................  2 
                  1.2  Shares To Be Issued; Reservation of Shares...............................................  2 

         2.  ADJUSTMENTS TO OPTION RIGHTS.......................................................................  2 

                  2.1  Stock Combinations.......................................................................  2 
                  2.2  Reorganizations..........................................................................  2 
                  2.3  Adjustment Upon Changes in Capitalization................................................  3 
                  2.4  Sales Below Fair Market Value............................................................  3 
                  2.5  Notice...................................................................................  5 
                  2.6  Fractional Interests.....................................................................  6 
                  2.7  Effect of Alternate Securities...........................................................  7 
                  2.8  Successive Application...................................................................  7 

         3.  EXERCISE...........................................................................................  7 

                  3.1  Exercise of Option.......................................................................  7 
                  3.2  Issuance of Option Shares................................................................  7 

         4.  RIGHTS OF HOLDER...................................................................................  7 

         5.  TRANSFERABILITY....................................................................................  7 

         6.  LEGEND ON OPTION SHARES............................................................................  8 

         7.  MISCELLANEOUS......................................................................................  8 

                  7.1  Amendments...............................................................................  8 
                  7.2  Notices..................................................................................  8 
                  7.3  Waiver By Consent........................................................................  9 
                  7.4  No Implied Waiver; Rights Are Cumulative.................................................  9 
                  7.5  Governing Law............................................................................  9 
                  7.6  Severability.............................................................................  9 
                  7.7  Captions.................................................................................  9 
                  7.8  Entire Agreement......................................................................... 10 




 
                                       -i-


   29



                  THE SECURITIES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER
                  THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT") OR UNDER
                  ANY APPLICABLE STATE LAW AND MAY NOT BE TRANSFERRED, SOLD OR
                  OTHERWISE DISPOSED OF IN THE ABSENCE OF AN EFFECTIVE
                  REGISTRATION UNDER THE ACT OR AN OPINION OF COUNSEL REASONABLY
                  SATISFACTORY TO THE ISSUER THAT SUCH REGISTRATION IS NOT
                  REQUIRED UNDER THE ACT AND THE RULES AND REGULATIONS
                  PROMULGATED THEREUNDER OR SUCH STATE SECURITIES LAWS AND
                  FURTHER PROVIDED THAT SUCH TRANSFER IS EFFECTED IN ACCORDANCE
                  WITH THE PROVISIONS OF SECTION 5.2(b) OF THAT CERTAIN STOCK
                  PURCHASE AGREEMENT BY AND BETWEEN THE ISSUER AND H. WAYNE
                  HUIZENGA, DATED AS OF MARCH 28, 1995.

                             FIRST OPTION AGREEMENT

                  This FIRST OPTION AGREEMENT (the "Option") is being entered
into this 28th day of March, 1995, by and between OHM Corporation, an Ohio
corporation (together with its successors and permitted assigns, the "Company")
and H. WAYNE HUIZENGA, an individual resident of the State of Florida (together
with his successors and permitted assigns, the "Buyer"). Capitalized terms used
herein and not otherwise defined herein shall have the meanings ascribed to them
in the Stock Purchase Agreement (as defined below).

                                    RECITALS

                  A. The Company and Buyer have entered into a Stock Purchase
Agreement dated as of the date hereof (the "Stock Purchase Agreement") pursuant
to which, among other things, the Company agreed to sell and Buyer agreed to
purchase certain shares of the Company's common stock, par value $.10 per share
(the "Common Stock").

                  B. Pursuant to the Stock Purchase Agreement, the Company has
agreed to grant to Buyer an option to purchase up to six hundred twenty thousand
(620,000) shares of Common Stock on the terms set forth in the Stock Purchase
Agreement and this Option.

                  NOW, THEREFORE, for the consideration set forth in the Stock
Purchase Agreement and other good and valuable consideration, the sufficiency
and receipt of which is hereby acknowledged, the Company agrees with Buyer as
follows:




   30



                  1.  GRANT OF OPTION.

                  1.1 GRANT. The Company hereby grants to Buyer this Option,
exercisable as provided herein in whole or in part at any time and from time to
time during the period from the date hereof through 6:00 p.m., local time in New
York, New York, on March 27, 2000 (the "Exercise Period") to purchase an
aggregate of up to Six Hundred Twenty Thousand (620,000) shares of Common Stock
(the "Option Shares"), at an exercise price of ten dollars ($10.00) per share
(as it may be hereinafter adjusted, the "Exercise Price"). Buyer and its
permitted successors and assigns are hereinafter referred to as "Holder."

                  1.2 SHARES TO BE ISSUED; RESERVATION OF SHARES. The Company
covenants and agrees that all Option Shares will, upon issuance, be duly
authorized, validly issued and outstanding, fully paid and non-assessable, and
free from all taxes, liens and charges with respect to the issuance thereof,
except as otherwise provided in the Stock Purchase Agreement. The Company
further covenants and agrees that it will from time to time take all actions
required to assure that the par value per share of the Common Stock is at all
times equal to or less than the effective Exercise Price. The Company further
covenants and agrees that, during the Exercise Period, the Company will at all
times have authorized and reserved sufficient shares of Common Stock to provide
for the exercise of this Option in full.

                  2.  ADJUSTMENTS TO OPTION RIGHTS.

                  2.1 STOCK COMBINATIONS. In case the Company shall combine all
of the outstanding Common Stock proportionately into a smaller number of shares,
the Exercise Price per Option Share hereunder in effect immediately prior to
such combination shall be proportionately increased and the number of Option
Shares issuable to the Holder upon exercise of this Option shall be
proportionately decreased, as of the effective date of such combination, as
follows: (a) the number of Option Shares purchasable upon the exercise of the
Option immediately prior to the effective date of such combination, shall be
adjusted so that the holder of the Option exercised after that date shall be
entitled to receive the number and kind of Option Shares which the holder of the
Option would have owned and been entitled to receive as a result of the
combination had the Options been exercised immediately prior to that date, and
(b) the Exercise Price in effect immediately prior to such adjustment shall be
adjusted by multiplying such Exercise Price by a fraction, the numerator of
which is the aggregate number of shares of Common Stock purchasable upon
exercise of the Options immediately prior to such adjustment, and the
denominator of which is the aggregate number of shares of Common Stock
purchasable upon exercise of the Options immediately thereafter.

                  2.2 REORGANIZATIONS. If any of the following transactions
(each, a "Special Transaction") shall become effective: (i) a capital
reorganization or reclassification of the capital stock of the Company, (ii) a
consolidation or merger of the Company with and into another entity, or (iii) a
sale or conveyance of all or substantially all of the Company's assets, then, as
a condition of any such Special Transaction, lawful and adequate provision shall
be made whereby the Holder shall thereafter have the right to purchase and
receive, at any time after the consummation of such Special Transaction until
the expiration of the Exercise Period, upon the basis and upon the terms and
conditions specified herein, and in



                                        2


   31



lieu of the Option Shares immediately theretofore issuable upon exercise of this
Option for the aggregate Exercise Price in effect immediately prior to such
consummation, such shares of stock, other securities, cash or other assets as
may be issued or payable in and pursuant to the terms of such Special
Transaction with respect to or in exchange for a number of outstanding shares of
Common Stock equal to the number of Option Shares immediately theretofore
issuable upon exercise of this Option had such Special Transaction not taken
place (pro rated in the case of any partial exercises). In connection with any
Special Transaction, appropriate provision shall be made with respect to the
rights and interests of the Holder to the end that the provisions of this Option
(including without limitation provisions for adjustment of the Exercise Price
and the number of Option Shares issuable upon the exercise of the Option), shall
thereafter be applicable, as nearly as may be, to any shares of stock, other
securities, cash or other assets thereafter deliverable upon the exercise of
this Option. The Company shall not effect any Special Transaction unless prior
to or simultaneously with the closing the successor entity (if other than the
Company), if any, resulting from such consolidation or merger or the entity
acquiring such assets shall assume by a written instrument executed and mailed
by certified mail or delivered to the Holder at the address of the Holder
appearing on the books of the Company, the obligation of the Company or such
successor corporation to deliver to such Holder such shares of stock,
securities, cash or other assets as, in accordance with the foregoing
provisions, such Holder has rights to purchase.

                  2.3 ADJUSTMENT UPON CHANGES IN CAPITALIZATION. In the event of
any change in the Common Stock by reason of stock dividends, stock splits,
recapitalizations or reclassifications, the type and number of Option Shares
issuable upon exercise of this Option, and the Exercise Price, as the case may
be, shall be adjusted as follows: (a) the number of Option Shares purchasable
upon the exercise of the Option immediately prior to the record date for such
dividend or distribution, or the effective date of such recapitalization or
reclassification shall be adjusted so that the holder of the Option exercised
after that date shall be entitled to receive the number and kind of Option
Shares which the holder of the Option would have owned and been entitled to
receive as a result of the dividend, distribution, recapitalization or
reclassification had the Options been exercised immediately prior to that date,
and (b) the Exercise Price in effect immediately prior to such adjustment shall
be adjusted by multiplying such Exercise Price by a fraction, the numerator of
which is the aggregate number of shares of Common Stock purchasable upon
exercise of the Options immediately prior to such adjustment, and the
denominator of which is the aggregate number of shares of Common Stock
purchasable upon exercise of the Options immediately thereafter. No such
adjustment shall be made on account of any dividend payable other than in
securities of the Company.

                  2.4 SALES BELOW FAIR MARKET VALUE. (a) In the event the
Company shall sell and issue shares of Common Stock, or rights, options,
warrants or convertible or exchangeable securities containing the right to
subscribe for or purchase shares of Common Stock (excluding (i) shares, rights,
options, warrants or convertible or exchangeable securities issued in any of the
transactions described in Sections 2.2 or 2.3 above and (ii) the Option and any
shares issued on exercise of the Option) at a price per share of Common Stock
(determined in the case of such rights, options, warrants or convertible or
exchangeable securities by dividing (X) the total amount receivable by the
Company in



                                        3


   32



consideration of the sale and issuance of such rights, options, warrants or
convertible or exchangeable securities, plus the total consideration payable to
the Company upon exercise, conversion or exchange thereof by (Y) the total
number of shares of Common Stock covered by such rights, options, warrants or
convertible or exchangeable securities) lower than the Current Market Price on
the date the Company fixes the offering price of such shares, rights, options,
warrants or convertible or exchangeable securities, then the Exercise Price
shall be adjusted so that it shall equal the price determined by multiplying the
Exercise Price in effect immediately prior thereto by a fraction, (i) the
numerator of which shall be the sum of (A) the number of shares of Common Stock
outstanding immediately prior to such sale and issuance plus (B) the number of
shares of Common Stock which the aggregate consideration received (determined as
provided below) for such sale or issuance would purchase at such Current Market
Price per share, and (ii) the denominator of which shall be the total number of
shares of Common Stock outstanding immediately after such sale and issuance. For
the purposes of such adjustment, the shares of Common Stock which the holder of
any such rights, options, warrants or convertible or exchangeable securities
shall be entitled to subscribe for or purchase shall be deemed to be issued and
outstanding as of the date of such sale and issuance and the consideration
received by the Company therefor shall be deemed to be the consideration
received by the Company for such rights, options, warrants or convertible or
exchangeable securities, plus the consideration or premium stated in such
rights, options, warrants or convertible or exchangeable securities to be paid
for the shares of Common Stock covered thereby. In case the Company shall sell
and issue rights, options, warrants or convertible or exchangeable securities
containing the right to subscribe for or purchase shares of Common Stock
together with one or more other securities as part of a unit at a price per
unit, then in determining the "price per share of Common Stock" and the
"consideration received by the Company" for purposes of the first sentence of
this Section 2.4, the Board of Directors of the Company shall determine, in good
faith, the fair value of the rights, options, warrants or convertible or
exchangeable securities then being sold as part of such unit, and such
determination, in the absence of fraud or bad faith, shall be binding upon all
holders of the Option.

         (b) For the purpose of any computation under this Section 2.4, the
"Current Market Price" at any date (the "Computation Date") shall be deemed to
be the average of the daily closing prices of the Common Stock for twenty (20)
consecutive New York Stock Exchange trading days ending the second New York
Stock Exchange trading day before such date; provided, however, that if there
shall have occurred prior to the Computation Date any event described in Section
2.2 or 2.3 which shall have become effective with respect to market transactions
at any time (the "Market-Effect Date") on or after the beginning of such 20-day
period, the closing price for each trading day preceding the Market-Effect Date
shall be adjusted, for purposes of calculating such average, by multiplying such
closing price by a fraction the numerator of which is the Exercise Price as in
effect immediately prior to the Computation Date and the denominator of which is
the Exercise Price as in effect immediately prior to the Market-Effect Date, it
being understood that the purpose of this proviso is to ensure that the effect
of such event on the market price of the Common Stock shall, as nearly as
possible, be eliminated in order that the distortion in the calculation of the
Current Market Price may be minimized. The "closing price" for any date shall be
the last reported sale price or, in case no such reported sale takes place on
such date, the average of



                                        4


   33



the last reported bid and asked prices on such day, in either case on the
principal national securities exchange on which the Common Stock is admitted to
trading or listed if that is the principal market for the Common Stock or if not
listed or admitted to trading on any national securities exchange or if such
national securities exchange is not the principal market for the Common Stock,
the closing bid price as reported by the National Association of Securities
Dealers Automated Quotation System or its successor, if any, or such other
generally accepted source of publicly reported bid and asked quotations as the
Company may reasonably designate. If the price of the Common Stock is not so
reported or the Common Stock is not publicly traded, the Current Market Price
per share as of any Computation Date shall be determined by the Board of
Directors in good faith as it considers appropriate.

         (c) All calculations under this Section 2.4 shall be made to the
nearest one- hundredth of a cent.

         (d) For the purposes of all calculations under this Section 2.4, shares
of Common Stock or other securities held in the treasury of the Company shall
not be deemed to be outstanding, and the sale or other disposition of any shares
of Common Stock or other securities held in the treasury of the Company shall be
deemed an issuance thereof.

         (e) No adjustment in the Exercise Price in accordance with the
provisions of Section 2.4 hereof need be made if such adjustment would amount to
a change in such Exercise Price of less than $.001; provided, however, that the
amount by which any adjustment is not made by reason of the provisions of this
Section 2.4 shall be carried forward and taken into account at the time of any
subsequent adjustment in the Exercise Price.

         No adjustment need be made in connection with the issuance of any
shares of Common Stock or options, warrants or convertible or exchangeable
securities (i) pursuant to any employee or director stock option, stock purchase
stock bonus plan or other employee or director benefit plan, (ii) in a bona fide
public offering pursuant to a firm commitment underwriting, or (iii) in
connection with mergers, acquisitions, consolidations, exchange offers, purchase
of assets or similar transactions or other transactions in which the
consideration for the issuance of Common Stock consists of property other than
cash.

         (f) Upon each adjustment of the Exercise Price pursuant to Section 2.4
hereof, the Option shall thereupon evidence the right to purchase that number of
shares of Common Stock (calculated to the nearest hundredth of a share) obtained
by multiplying the number of shares of Common Stock purchasable immediately
prior to such adjustment upon exercise of the Option by the Exercise Price in
effect immediately prior to such adjustment and dividing the product so obtained
by the Exercise Price in effect immediately after such adjustment. The
adjustment pursuant to this Section 2.4 to the number of shares of Common Stock
purchasable upon exercise of an Option shall be made each time an adjustment of
the Exercise Price is made pursuant to Section 2.4 hereof.

                  2.5 NOTICE. Whenever this Option or the number of Option
Shares issuable hereunder is to be adjusted as provided herein or a dividend or
distribution (in cash, stock or



                                        5


   34



otherwise and including, without limitation, any liquidating distributions) is
to be declared by the Company, or a definitive agreement with respect to a
Special Transaction has been entered into, the Company shall forthwith cause to
be sent to the Holder at the last address of the Holder shown on the books of
the Company, by first-class mail, postage prepaid, at least ten (10) days prior
to the record date specified in (A) below or at least twenty (20) days before
the date specified in (B) below, a notice stating in reasonable detail the
relevant facts and any resulting adjustments and the calculation thereof, if
applicable, and stating (if applicable):

                           (A) the date to be used to determine (i) which
holders of Common Stock will be entitled to receive notice of such dividend,
distribution, subdivision or combination (the "Record Date"), and (ii) the date
as of which such dividend distribution, subdivision or combination shall be
made; or, if a record is not to be taken, the date as of which the holders of
Common Stock of record to be entitled to such dividend, distribution,
subdivision or combination are to be determined (provided, that in the event the
Company institutes a policy of declaring cash dividends on a periodic basis, the
Company need only provide the relevant information called for in this clause (A)
with respect to the first cash dividend payment to be made pursuant to such
policy and thereafter provide only notice of any changes in the amount or the
frequency of any subsequent dividend payments), or

                           (B) the date on which a Special Transaction is
expected to become effective, and the date as of which it is expected that
holders of Common Stock of record shall be entitled to exchange their shares of
Common Stock for securities or other property deliverable upon consummation of
the Special Transaction (the "Exchange Date").

                           Upon delivery to Holder of a notice contemplated by
either of clause (A) or clause (B) above, during the Holding Period, as such
term is defined in Section 6.1 of the Stock Purchase Agreement, Holder shall be
deemed a stockholder as of the Record Date or Exchange Date, as the case may be,
despite any delay in the exercise of the Option resulting from holding or
waiting periods required by any Government Authority, as such term is defined in
Section 6.1 of the Stock Purchase Agreement, including, but not limited to, the
holding or waiting period applicable under the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended; provided that (i) upon receipt of the
notice referenced above and prior to the Record Date or the Exchange Date, as
applicable, Holder shall deliver written confirmation to the Company stating
that Holder intends to exercise all or a portion of the Option, upon expiration
of the applicable holding or waiting period, and (ii) Holder, in fact, exercises
such Option within 10 days of the expiration of the applicable holding or
waiting period.

                  2.6 FRACTIONAL INTERESTS. The Company shall not be required to
issue fractions of shares of Common Stock on the exercise of this Option. If any
fraction of a share of Common Stock would, except for the provisions of this
Section 2.6, be issuable upon the exercise of this Option, the Company shall,
upon such issuance, purchase such fraction for an amount in cash equal to the
current value of such fraction, computed on the basis of the last reported close
price of the Common Stock on the New York Stock Exchange ("NYSE") on the last
business day prior to the date of exercise upon which such a sale shall



                                        6


   35



have been effected, or, if the Common Stock is not so listed on the NYSE, as the
Board of Directors of the Issuer may in good faith determine.

                  2.7 EFFECT OF ALTERNATE SECURITIES. If at any time, as a
result of an adjustment made pursuant to this Section 2, the holder of the
Options shall thereafter become entitled to receive any securities of the
Company other than shares of Common Stock, then the number of such other
securities receivable upon exercise of an Option shall be subject to adjustment
from time to time on terms as nearly equivalent as practicable to the provisions
with respect to shares of Common Stock contained in this Section 2.

                  2.8 SUCCESSIVE APPLICATION. The provisions of this Section 2
shall similarly apply to successive events covered by this Section.

                  3.  EXERCISE.

                  3.1 EXERCISE OF OPTION. (a) The Holder may exercise this
Option by (i) surrendering this Option, with the form of exercise notice
attached hereto as Exhibit "A" duly executed by Holder, and (ii) making payment
to the Company of the aggregate Exercise Price for the applicable Option Shares
in cash, by certified check or bank check or by wire transfer to an account
designated by the Company. Upon any partial exercise of this Option, the
Company, at its expense, shall forthwith issue to the Holder for its surrendered
option a replacement Option identical in all respects to this Option, except
that the number of Option Shares shall be reduced accordingly.

         (b) Record Date for ownership of Option Shares. Each person in whose
name any Option Share certificate is issued upon exercise of the Options shall
for all purposes been deemed to have become the holder of record of the Option
Shares for which such Options were exercised on, and such Option Share
certificate shall be dated the date upon which the Option exercise notice was
duly surrendered and payment of the Exercise Price was tendered to the Company.

                  3.2 ISSUANCE OF OPTION SHARES. The Option Shares purchased
shall be issued to the Holder exercising this Option as of the close of business
on the date on which all actions and payments required to be taken or made by
Holder, pursuant to Section 3.1, shall have been so taken or made. Certificates
for the Option Shares so purchased shall be delivered to the Holder within a
reasonable time, not exceeding ten (10) days after this Option is surrendered.

                  4. RIGHTS OF HOLDER. Holder shall not, solely by virtue of
this Option and prior to the issuance of the Option Shares upon due exercise
thereof, be entitled to any rights of a shareholder in the Company.

                  5. TRANSFERABILITY. Holder hereby represents and warrants that
it is acquiring this Option and, upon the exercise thereof, the Option Shares,
for investment and not with a view to resale or distribution thereof. Holder may
not sell, assign, transfer or otherwise dispose of this Option or any Option
Shares, except in accordance with the terms



                                        7


   36



of the Stock Purchase Agreement. Subject to compliance with federal and state
securities laws and with the Stock Purchase Agreement, if applicable, the Holder
may sell, assign, transfer or otherwise dispose of any Option Shares acquired
upon any exercise hereof at any time and from time to time.

                  6. LEGEND ON OPTION SHARES. Certificates evidencing the Option
Shares shall bear the legend set forth in Section 1.2 of the Stock Purchase
Agreement.

                  7.  MISCELLANEOUS.

                  7.1 AMENDMENTS. The parties may, from time to time, enter into
written amendments, supplements or modifications hereto for the purpose of
adding any provisions to this Option or changing in any manner the rights of
either of the parties hereunder. No amendment, supplement or modification shall
be binding on either party unless made in writing and signed by a duly
authorized representative of each party.

                  7.2 NOTICES. All notices, requests, demands, claims, and other
communications hereunder shall be in writing and shall be delivered by certified
or registered mail (first class postage pre-paid), guaranteed overnight
delivery, or facsimile transmission, which transmission is confirmed by delivery
by certified or registered mail (first class postage pre-paid) or guaranteed
overnight delivery:

                  (a)      if to Issuer to:

                           OHM Corporation
                           16406 U.S. Route 224 East
                           Findlay, Ohio 45840
                           Attention: General Counsel

                           Telecopy: (419) 424-4985

                           with a copy to:
                           Jones, Day, Reavis & Pogue
                           41 South High Street
                           1900 Huntington Center
                           Columbus, OH  43215
                           Attention:  Robert J. Gilker, Esq.

                           Telecopy:  (614) 469-4198



                                        8


   37



                  (b)      if to Investor to:

                           H. Wayne Huizenga
                           200 South Andrews Avenue
                           Fort Lauderdale, Florida 33301
                           Attention:  Richard C. Rochon

                           Telecopy: (305) 523-0801

                           with a copy to:
                           Akerman, Senterfitt & Eidson, P.A.
                           24th Floor, One Brickell Square
                           801 Brickell Avenue
                           Miami, FL  33131
                           Attention:  Stephen K. Roddenberry, Esq.

                           Telecopy:  (305) 374-5095

                  (c) or, in each case, at such other address or to such other
person as may be specified in writing to the other party.

                  7.3 WAIVER BY CONSENT. The Holder may execute and deliver to
the Company a written instrument waiving, on such terms and conditions as the
Holder may specify in such instrument, any of the requirements of this Option.

                  7.4 NO IMPLIED WAIVER; RIGHTS ARE CUMULATIVE. The failure to
exercise or the delay in exercising by either party of any right, remedy, power
or privilege under this Option, shall not operate as a waiver thereof. The
single or partial exercise of any right, remedy, power or privilege under this
Option shall not preclude any other or further exercise thereof or the exercise
of any other right, remedy, power or privilege. The rights, remedies, powers and
privileges herein provided are cumulative and not exclusive of any rights,
remedies, powers and privileges provided by law.

                  7.5 GOVERNING LAW. This Option and rights and obligations of
the parties hereunder shall be governed by, construed and interpreted in
accordance with the laws of the State of Ohio applicable to agreements executed
by residents of that state, and fully to be performed, in that state.

                  7.6 SEVERABILITY. If any provision of this Option is found to
be unenforceable for any reason whatsoever, such provision shall be deemed null
and void to the extent of such unenforceability but shall be deemed separable
from and shall not invalidate any other provision of this Option.

                  7.7 CAPTIONS. Captions to the various paragraphs of this
Agreement are provided for convenience only and shall not be used to construe
the provisions of this Option.



                                        9


   38



                  7.8 ENTIRE AGREEMENT. This Option and such portions of the
Stock Purchase Agreement and the Second Option Agreement contemplated thereby
constitute the entire understanding of the parties with respect to the subject
matter of the Option and supersedes all prior discussions, agreements and
representations, whether oral or written, concerning the subject matter hereof
and whether or not executed by Buyer and the Company.

                  IN WITNESS WHEREOF, the parties hereto have caused this
Agreement to be duly executed and delivered by the proper and duly authorized
officers as of the day and year first above written.

                                       /s/ H. WAYNE HUIZENGA
                                       -----------------------------------------
                                       H. Wayne Huizenga


                                       OHM CORPORATION


                                       By: /s/ RANDALL M. WALTERS
                                       -----------------------------------------
                                       Name: Randall M. Walters
                                       Title:   Vice President, General Counsel
                                                and Secretary


                                       10


   39


                                                                     EXHIBIT "A"

                  [To be signed only upon exercise of Option]
To OHM Corporation:

                  The undersigned, the Holder of the within Option, hereby
irrevocably elects to exercise the purchase right represented by such Option
for, and to purchase thereunder, _____________ shares of the common stock, par
value $.10 per share, of OHM Corporation and herewith makes payment of
$___________ thereof or, and requests that the certificates for such shares be
issued in the name of, and be delivered to, ______________ whose address is
___________________________.


Dated:

____________________________

                           _______________________
                           (Signature must conform in all respects to name
                           of Holder as specified on the face of the Option)

                           _______________________
                           Address




   40


                                                                       EXHIBIT B
================================================================================
- --------------------------------------------------------------------------------







                             SECOND OPTION AGREEMENT

                                 by and between

                                H. WAYNE HUIZENGA

                                       and

                                 OHM CORPORATION

                           Dated as of March 28, 1995







- --------------------------------------------------------------------------------
================================================================================







   41








                                TABLE OF CONTENTS



                                                                                                               PAGE
                                              
                                                                                                             
         1.  GRANT OF OPTION....................................................................................  2

                  1.1  Grant....................................................................................  2
                  1.2  Shares To Be Issued; Reservation of Shares...............................................  2

         2.  ADJUSTMENTS TO OPTION RIGHTS.......................................................................  2

                  2.1  Stock Combinations.......................................................................  2
                  2.2  Reorganizations..........................................................................  2
                  2.3  Adjustment Upon Changes in Capitalization................................................  3
                  2.4  Sales Below Fair Market Value............................................................  3
                  2.5  Notice...................................................................................  5
                  2.6  Fractional Interests.....................................................................  6
                  2.7  Effect of Alternate Securities...........................................................  7
                  2.8  Successive Application...................................................................  7

         3.  EXERCISE...........................................................................................  7

                  3.1  Exercise of Option.......................................................................  7
                  3.2  Issuance of Option Shares................................................................  7

         4.  RIGHTS OF HOLDER...................................................................................  7

         5.  TRANSFERABILITY....................................................................................  7

         6.  LEGEND ON OPTION SHARES............................................................................  8

         7.  MISCELLANEOUS......................................................................................  8

                  7.1  Amendments...............................................................................  8
                  7.2  Notices..................................................................................  8
                  7.3  Waiver By Consent........................................................................  9
                  7.4  No Implied Waiver; Rights Are Cumulative.................................................  9
                  7.5  Governing Law............................................................................  9
                  7.6  Severability.............................................................................  9
                  7.7  Captions.................................................................................  9
                  7.8  Entire Agreement......................................................................... 10






                                       -i-


   42



                  THE SECURITIES EVIDENCED HEREBY HAVE NOT BEEN REGISTERED UNDER
                  THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT") OR UNDER
                  ANY APPLICABLE STATE LAW AND MAY NOT BE TRANSFERRED, SOLD OR
                  OTHERWISE DISPOSED OF IN THE ABSENCE OF AN EFFECTIVE
                  REGISTRATION UNDER THE ACT OR AN OPINION OF COUNSEL REASONABLY
                  SATISFACTORY TO THE ISSUER THAT SUCH REGISTRATION IS NOT
                  REQUIRED UNDER THE ACT AND THE RULES AND REGULATIONS
                  PROMULGATED THEREUNDER OR SUCH STATE SECURITIES LAWS AND
                  FURTHER PROVIDED THAT SUCH TRANSFER IS EFFECTED IN ACCORDANCE
                  WITH THE PROVISIONS OF SECTION 5.2(b) OF THAT CERTAIN STOCK
                  PURCHASE AGREEMENT BY AND BETWEEN THE ISSUER AND H. WAYNE
                  HUIZENGA, DATED AS OF MARCH 28, 1995.

                             SECOND OPTION AGREEMENT

                  This SECOND OPTION AGREEMENT (the "Option") is being entered
into this 28th day of March, 1995, by and between OHM Corporation, an Ohio
corporation (together with its successors and permitted assigns, the "Company")
and H. WAYNE HUIZENGA, an individual resident of the State of Florida (together
with his successors and permitted assigns, the "Buyer"). Capitalized terms used
herein and not otherwise defined herein shall have the meanings ascribed to them
in the Securities Purchase Agreement (as defined below).

                                    RECITALS

                  A. The Company and Buyer have entered into a Stock Purchase
Agreement dated as of the date hereof (the "Stock Purchase Agreement") pursuant
to which, among other things, the Company agreed to sell and Buyer agreed to
purchase certain shares of the Company's common stock, par value $.10 per share
(the "Common Stock").

                  B. Pursuant to the Stock Purchase Agreement, the Company has
agreed to grant to Buyer an option to purchase up to three hundred eighty
thousand (380,000) shares of Common Stock on the terms set forth in the Stock
Purchase Agreement and this Option.

                  NOW, THEREFORE, for the consideration set forth in the Stock
Purchase Agreement and other good and valuable consideration, the sufficiency
and receipt of which is hereby acknowledged, the Company agrees with Buyer as
follows:


   43



                  1.  GRANT OF OPTION.

                  1.1 GRANT. The Company hereby grants to Buyer this Option,
exercisable as provided herein in whole or in part at any time and from time to
time during the period from the date hereof through 6:00 p.m., local time in New
York, New York, on March 27, 2000 (the "Exercise Period") to purchase an
aggregate of up to Three Hundred Eighty Thousand (380,000) shares of Common
Stock (the "Option Shares"), at an exercise price of twelve dollars ($12.00) per
share (as it may be hereinafter adjusted, the "Exercise Price"). Buyer and its
permitted successors and assigns are hereinafter referred to as "Holder."

                  1.2 SHARES TO BE ISSUED; RESERVATION OF SHARES. The Company
covenants and agrees that all Option Shares will, upon issuance, be duly
authorized, validly issued and outstanding, fully paid and non-assessable, and
free from all taxes, liens and charges with respect to the issuance thereof,
except as otherwise provided in the Stock Purchase Agreement. The Company
further covenants and agrees that it will from time to time take all actions
required to assure that the par value per share of the Common Stock is at all
times equal to or less than the effective Exercise Price. The Company further
covenants and agrees that, during the Exercise Period, the Company will at all
times have authorized and reserved sufficient shares of Common Stock to provide
for the exercise of this Option in full.

                  2.  ADJUSTMENTS TO OPTION RIGHTS.

                  2.1 STOCK COMBINATIONS. In case the Company shall combine all
of the outstanding Common Stock proportionately into a smaller number of shares,
the Exercise Price per Option Share hereunder in effect immediately prior to
such combination shall be proportionately increased and the number of Option
Shares issuable to the Holder upon exercise of this Option shall be
proportionately decreased, as of the effective date of such combination, as
follows: (a) the number of Option Shares purchasable upon the exercise of the
Option immediately prior to the effective date of such combination, shall be
adjusted so that the holder of the Option exercised after that date shall be
entitled to receive the number and kind of Option Shares which the holder of the
Option would have owned and been entitled to receive as a result of the
combination had the Options been exercised immediately prior to that date, and
(b) the Exercise Price in effect immediately prior to such adjustment shall be
adjusted by multiplying such Exercise Price by a fraction, the numerator of
which is the aggregate number of shares of Common Stock purchasable upon
exercise of the Options immediately prior to such adjustment, and the
denominator of which is the aggregate number of shares of Common Stock
purchasable upon exercise of the Options immediately thereafter.

                  2.2 REORGANIZATIONS. If any of the following transactions
(each, a "Special Transaction") shall become effective: (i) a capital
reorganization or reclassification of the capital stock of the Company, (ii) a
consolidation or merger of the Company with and into another entity, or (iii) a
sale or conveyance of all or substantially all of the Company's assets, then, as
a condition of any such Special Transaction, lawful and adequate provision shall
be made whereby the Holder shall thereafter have the right to purchase and
receive, at any time after the consummation of such Special Transaction until
the expiration of the Exercise Period, upon the basis and upon the terms and
conditions specified herein, and in

                                        2


   44



lieu of the Option Shares immediately theretofore issuable upon exercise of this
Option for the aggregate Exercise Price in effect immediately prior to such
consummation, such shares of stock, other securities, cash or other assets as
may be issued or payable in and pursuant to the terms of such Special
Transaction with respect to or in exchange for a number of outstanding shares of
Common Stock equal to the number of Option Shares immediately theretofore
issuable upon exercise of this Option had such Special Transaction not taken
place (pro rated in the case of any partial exercises). In connection with any
Special Transaction, appropriate provision shall be made with respect to the
rights and interests of the Holder to the end that the provisions of this Option
(including without limitation provisions for adjustment of the Exercise Price
and the number of Option Shares issuable upon the exercise of the Option), shall
thereafter be applicable, as nearly as may be, to any shares of stock, other
securities, cash or other assets thereafter deliverable upon the exercise of
this Option. The Company shall not effect any Special Transaction unless prior
to or simultaneously with the closing the successor entity (if other than the
Company), if any, resulting from such consolidation or merger or the entity
acquiring such assets shall assume by a written instrument executed and mailed
by certified mail or delivered to the Holder at the address of the Holder
appearing on the books of the Company, the obligation of the Company or such
successor corporation to deliver to such Holder such shares of stock,
securities, cash or other assets as, in accordance with the foregoing
provisions, such Holder has rights to purchase.

                  2.3 ADJUSTMENT UPON CHANGES IN CAPITALIZATION. In the event of
any change in the Common Stock by reason of stock dividends, stock splits,
recapitalizations or reclassifications, the type and number of Option Shares
issuable upon exercise of this Option, and the Exercise Price, as the case may
be, shall be adjusted as follows: (a) the number of Option Shares purchasable
upon the exercise of the Option immediately prior to the record date for such
dividend or distribution, or the effective date of such recapitalization or
reclassification shall be adjusted so that the holder of the Option exercised
after that date shall be entitled to receive the number and kind of Option
Shares which the holder of the Option would have owned and been entitled to
receive as a result of the dividend, distribution, recapitalization or
reclassification had the Options been exercised immediately prior to that date,
and (b) the Exercise Price in effect immediately prior to such adjustment shall
be adjusted by multiplying such Exercise Price by a fraction, the numerator of
which is the aggregate number of shares of Common Stock purchasable upon
exercise of the Options immediately prior to such adjustment, and the
denominator of which is the aggregate number of shares of Common Stock
purchasable upon exercise of the Options immediately thereafter. No such
adjustment shall be made on account of any dividend payable other than in
securities of the Company.

                  2.4 SALES BELOW FAIR MARKET VALUE. (a) In the event the
Company shall sell and issue shares of Common Stock, or rights, options,
warrants or convertible or exchangeable securities containing the right to
subscribe for or purchase shares of Common Stock (excluding (i) shares, rights,
options, warrants or convertible or exchangeable securities issued in any of the
transactions described in Sections 2.2 or 2.3 above and (ii) the Option and any
shares issued on exercise of the Option) at a price per share of Common Stock
(determined in the case of such rights, options, warrants or convertible or
exchangeable securities by dividing (X) the total amount receivable by the
Company in

                                        3


   45



consideration of the sale and issuance of such rights, options, warrants or
convertible or exchangeable securities, plus the total consideration payable to
the Company upon exercise, conversion or exchange thereof by (Y) the total
number of shares of Common Stock covered by such rights, options, warrants or
convertible or exchangeable securities) lower than the Current Market Price on
the date the Company fixes the offering price of such shares, rights, options,
warrants or convertible or exchangeable securities, then the Exercise Price
shall be adjusted so that it shall equal the price determined by multiplying the
Exercise Price in effect immediately prior thereto by a fraction, (i) the
numerator of which shall be the sum of (A) the number of shares of Common Stock
outstanding immediately prior to such sale and issuance plus (B) the number of
shares of Common Stock which the aggregate consideration received (determined as
provided below) for such sale or issuance would purchase at such Current Market
Price per share, and (ii) the denominator of which shall be the total number of
shares of Common Stock outstanding immediately after such sale and issuance. For
the purposes of such adjustment, the shares of Common Stock which the holder of
any such rights, options, warrants or convertible or exchangeable securities
shall be entitled to subscribe for or purchase shall be deemed to be issued and
outstanding as of the date of such sale and issuance and the consideration
received by the Company therefor shall be deemed to be the consideration
received by the Company for such rights, options, warrants or convertible or
exchangeable securities, plus the consideration or premium stated in such
rights, options, warrants or convertible or exchangeable securities to be paid
for the shares of Common Stock covered thereby. In case the Company shall sell
and issue rights, options, warrants or convertible or exchangeable securities
containing the right to subscribe for or purchase shares of Common Stock
together with one or more other securities as part of a unit at a price per
unit, then in determining the "price per share of Common Stock" and the
"consideration received by the Company" for purposes of the first sentence of
this Section 2.4, the Board of Directors of the Company shall determine, in good
faith, the fair value of the rights, options, warrants or convertible or
exchangeable securities then being sold as part of such unit, and such
determination, in the absence of fraud or bad faith, shall be binding upon all
holders of the Option.

         (b) For the purpose of any computation under this Section 2.4, the
"Current Market Price" at any date (the "Computation Date") shall be deemed to
be the average of the daily closing prices of the Common Stock for twenty (20)
consecutive New York Stock Exchange trading days ending the second New York
Stock Exchange trading day before such date; provided, however, that if there
shall have occurred prior to the Computation Date any event described in Section
2.2 or 2.3 which shall have become effective with respect to market transactions
at any time (the "Market-Effect Date") on or after the beginning of such 20-day
period, the closing price for each trading day preceding the Market-Effect Date
shall be adjusted, for purposes of calculating such average, by multiplying such
closing price by a fraction the numerator of which is the Exercise Price as in
effect immediately prior to the Computation Date and the denominator of which is
the Exercise Price as in effect immediately prior to the Market-Effect Date, it
being understood that the purpose of this proviso is to ensure that the effect
of such event on the market price of the Common Stock shall, as nearly as
possible, be eliminated in order that the distortion in the calculation of the
Current Market Price may be minimized. The "closing price" for any date shall be
the last reported sale price or, in case no such reported sale takes place on
such date, the average of

                                        4


   46



the last reported bid and asked prices on such day, in either case on the
principal national securities exchange on which the Common Stock is admitted to
trading or listed if that is the principal market for the Common Stock or if not
listed or admitted to trading on any national securities exchange or if such
national securities exchange is not the principal market for the Common Stock,
the closing bid price as reported by the National Association of Securities
Dealers Automated Quotation System or its successor, if any, or such other
generally accepted source of publicly reported bid and asked quotations as the
Company may reasonably designate. If the price of the Common Stock is not so
reported or the Common Stock is not publicly traded, the Current Market Price
per share as of any Computation Date shall be determined by the Board of
Directors in good faith as it considers appropriate.

         (c)      All calculations under this Section 2.4 shall be made to the 
nearest one - hundredth of a cent.

         (d) For the purposes of all calculations under this Section 2.4, shares
of Common Stock or other securities held in the treasury of the Company shall
not be deemed to be outstanding, and the sale or other disposition of any shares
of Common Stock or other securities held in the treasury of the Company shall be
deemed an issuance thereof.

         (e) No adjustment in the Exercise Price in accordance with the
provisions of Section 2.4 hereof need be made if such adjustment would amount to
a change in such Exercise Price of less than $.001; provided, however, that the
amount by which any adjustment is not made by reason of the provisions of this
Section 2.4 shall be carried forward and taken into account at the time of any
subsequent adjustment in the Exercise Price.

         No adjustment need be made in connection with the issuance of any
shares of Common Stock or options, warrants or convertible or exchangeable
securities (i) pursuant to any employee or director stock option, stock purchase
stock bonus plan or other employee or director benefit plan, (ii) in a bona fide
public offering pursuant to a firm commitment underwriting, or (iii) in
connection with mergers, acquisitions, consolidations, exchange offers, purchase
of assets or similar transactions or other transactions in which the
consideration for the issuance of Common Stock consists of property other than
cash.

         (f) Upon each adjustment of the Exercise Price pursuant to Section 2.4
hereof, the Option shall thereupon evidence the right to purchase that number of
shares of Common Stock (calculated to the nearest hundredth of a share) obtained
by multiplying the number of shares of Common Stock purchasable immediately
prior to such adjustment upon exercise of the Option by the Exercise Price in
effect immediately prior to such adjustment and dividing the product so obtained
by the Exercise Price in effect immediately after such adjustment. The
adjustment pursuant to this Section 2.4 to the number of shares of Common Stock
purchasable upon exercise of an Option shall be made each time an adjustment of
the Exercise Price is made pursuant to Section 2.4 hereof.

                  2.5 NOTICE. Whenever this Option or the number of Option
Shares issuable hereunder is to be adjusted as provided herein or a dividend or
distribution (in cash, stock or

                                        5


   47



otherwise and including, without limitation, any liquidating distributions) is
to be declared by the Company, or a definitive agreement with respect to a
Special Transaction has been entered into, the Company shall forthwith cause to
be sent to the Holder at the last address of the Holder shown on the books of
the Company, by first-class mail, postage prepaid, at least ten (10) days prior
to the record date specified in (A) below or at least twenty (20) days before
the date specified in (B) below, a notice stating in reasonable detail the
relevant facts and any resulting adjustments and the calculation thereof, if
applicable, and stating (if applicable):

                           (A) the date to be used to determine (i) which
holders of Common

Stock will be entitled to receive notice of such dividend, distribution,
subdivision or combination (the "Record Date"), and (ii) the date as of which
such dividend distribution, subdivision or combination shall be made; or, if a
record is not to be taken, the date as of which the holders of Common Stock of
record to be entitled to such dividend, distribution, subdivision or combination
are to be determined (provided, that in the event the Company institutes a
policy of declaring cash dividends on a periodic basis, the Company need only
provide the relevant information called for in this clause (A) with respect to
the first cash dividend payment to be made pursuant to such policy and
thereafter provide only notice of any changes in the amount or the frequency of
any subsequent dividend payments), or

                           (B) the date on which a Special Transaction is
expected to become effective, and the date as of which it is expected that
holders of Common Stock of record shall be entitled to exchange their shares of
Common Stock for securities or other property deliverable upon consummation of
the Special Transaction (the "Exchange Date").

                           Upon delivery to Holder of a notice contemplated by
either of clause (A) or clause (B) above, during the Holding Period, as such
term is defined in Section 6.1 of the Stock Purchase Agreement, Holder shall be
deemed a stockholder as of the Record Date or Exchange Date, as the case may be,
despite any delay in the exercise of the Option resulting from holding or
waiting periods required by any Government Authority, as such term is defined in
Section 6.1 of the Stock Purchase Agreement, including, but not limited to, the
holding or waiting period applicable under the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended; provided that (i) upon receipt of the
notice referenced above and prior to the Record Date or the Exchange Date, as
applicable, Holder shall deliver written confirmation to the Company stating
that Holder intends to exercise all or a portion of the Option, upon expiration
of the applicable holding or waiting period, and (ii) Holder, in fact, exercises
such Option within 10 days of the expiration of the applicable holding or
waiting period.

                  2.6 FRACTIONAL INTERESTS. The Company shall not be required to
issue fractions of shares of Common Stock on the exercise of this Option. If any
fraction of a share of Common Stock would, except for the provisions of this
Section 2.6, be issuable upon the exercise of this Option, the Company shall,
upon such issuance, purchase such fraction for an amount in cash equal to the
current value of such fraction, computed on the basis of the last reported close
price of the Common Stock on the New York Stock Exchange ("NYSE") on the last
business day prior to the date of exercise upon which such a sale shall

                                        6


   48



have been effected, or, if the Common Stock is not so listed on the NYSE, as the
Board of Directors of the Issuer may in good faith determine.

                  2.7 EFFECT OF ALTERNATE SECURITIES. If at any time, as a
result of an adjustment made pursuant to this Section 2, the holder of the
Options shall thereafter become entitled to receive any securities of the
Company other than shares of Common Stock, then the number of such other
securities receivable upon exercise of an Option shall be subject to adjustment
from time to time on terms as nearly equivalent as practicable to the provisions
with respect to shares of Common Stock contained in this Section 2.

                  2.8 SUCCESSIVE APPLICATION. The provisions of this Section 2
shall similarly apply to successive events covered by this Section.

                  3.  EXERCISE.

                  3.1 EXERCISE OF OPTION. (a) The Holder may exercise this
Option by (i) surrendering this Option, with the form of exercise notice
attached hereto as Exhibit "A" duly executed by Holder, and (ii) making payment
to the Company of the aggregate Exercise Price for the applicable Option Shares
in cash, by certified check or bank check or by wire transfer to an account
designated by the Company. Upon any partial exercise of this Option, the
Company, at its expense, shall forthwith issue to the Holder for its surrendered
option a replacement Option identical in all respects to this Option, except
that the number of Option Shares shall be reduced accordingly.

         (b) Record Date for ownership of Option Shares. Each person in whose
name any Option Share certificate is issued upon exercise of the Options shall
for all purposes been deemed to have become the holder of record of the Option
Shares for which such Options were exercised on, and such Option Share
certificate shall be dated the date upon which the Option exercise notice was
duly surrendered and payment of the Exercise Price was tendered to the Company.

                  3.2 ISSUANCE OF OPTION SHARES. The Option Shares purchased
shall be issued to the Holder exercising this Option as of the close of business
on the date on which all actions and payments required to be taken or made by
Holder, pursuant to Section 3.1, shall have been so taken or made. Certificates
for the Option Shares so purchased shall be delivered to the Holder within a
reasonable time, not exceeding ten (10) days after this Option is surrendered.

                  4. RIGHTS OF HOLDER. Holder shall not, solely by virtue of
this Option and prior to the issuance of the Option Shares upon due exercise
thereof, be entitled to any rights of a shareholder in the Company.

                  5. TRANSFERABILITY. Holder hereby represents and warrants that
it is acquiring this Option and, upon the exercise thereof, the Option Shares,
for investment and not with a view to resale or distribution thereof. Holder may
not sell, assign, transfer or otherwise dispose of this Option or any Option
Shares, except in accordance with the terms

                                        7


   49



of the Stock Purchase Agreement. Subject to compliance with federal and state
securities laws and with the Stock Purchase Agreement, if applicable, the Holder
may sell, assign, transfer or otherwise dispose of any Option Shares acquired
upon any exercise hereof at any time and from time to time.

                  6. LEGEND ON OPTION SHARES. Certificates evidencing the Option
Shares shall bear the legend set forth in Section 1.2 of the Stock Purchase
Agreement.

                  7. MISCELLANEOUS.

                  7.1 AMENDMENTS. The parties may, from time to time, enter into
written amendments, supplements or modifications hereto for the purpose of
adding any provisions to this Option or changing in any manner the rights of
either of the parties hereunder. No amendment, supplement or modification shall
be binding on either party unless made in writing and signed by a duly
authorized representative of each party.

                  7.2 NOTICES. All notices, requests, demands, claims, and other
communications hereunder shall be in writing and shall be delivered by certified
or registered mail (first class postage pre-paid), guaranteed overnight
delivery, or facsimile transmission, which transmission is confirmed by delivery
by certified or registered mail (first class postage pre-paid) or guaranteed
overnight delivery:

                  (a)      if to Issuer to:

                           OHM Corporation
                           16406 U.S. Route 224 East
                           Findlay, Ohio 45840
                           Attention: General Counsel

                           Telecopy: (419) 424-4985

                           with a copy to:
                           Jones, Day, Reavis & Pogue
                           41 South High Street
                           1900 Huntington Center
                           Columbus, OH  43215
                           Attention:  Robert J. Gilker, Esq.

                           Telecopy:  (614) 469-4198

                                        8


   50



                  (b)      if to Investor to:

                           H. Wayne Huizenga
                           200 South Andrews Avenue
                           Fort Lauderdale, Florida 33301
                           Attention:  Richard C. Rochon

                           Telecopy: (305) 523-0801

                           with a copy to:
                           Akerman, Senterfitt & Eidson, P.A.
                           24th Floor, One Brickell Square
                           801 Brickell Avenue
                           Miami, FL  33131
                           Attention:  Stephen K. Roddenberry, Esq.

                           Telecopy:  (305) 374-5095

                  (c) or, in each case, at such other address or to such other
person as may be specified in writing to the other party.

                  7.3 WAIVER BY CONSENT. The Holder may execute and deliver to
the Company a written instrument waiving, on such terms and conditions as the
Holder may specify in such instrument, any of the requirements of this Option.

                  7.4 NO IMPLIED WAIVER; RIGHTS ARE CUMULATIVE. The failure to
exercise or the delay in exercising by either party of any right, remedy, power
or privilege under this Option, shall not operate as a waiver thereof. The
single or partial exercise of any right, remedy, power or privilege under this
Option shall not preclude any other or further exercise thereof or the exercise
of any other right, remedy, power or privilege. The rights, remedies, powers and
privileges herein provided are cumulative and not exclusive of any rights,
remedies, powers and privileges provided by law.

                  7.5 GOVERNING LAW. This Option and rights and obligations of
the parties hereunder shall be governed by, construed and interpreted in
accordance with the laws of the State of Ohio applicable to agreements executed
by residents of that state, and fully to be performed, in that state.

                  7.6 SEVERABILITY. If any provision of this Option is found to
be unenforceable for any reason whatsoever, such provision shall be deemed null
and void to the extent of such unenforceability but shall be deemed separable
from and shall not invalidate any other provision of this Option.

                  7.7 CAPTIONS. Captions to the various paragraphs of this
Agreement are provided for convenience only and shall not be used to construe
the provisions of this Option.

                                        9


   51



                  7.8 ENTIRE AGREEMENT. This Option and such portions of the
Stock Purchase Agreement and the First Option Agreement contemplated thereby
constitute the entire understanding of the parties with respect to the subject
matter of the Option and supersedes all prior discussions, agreements and
representations, whether oral or written, concerning the subject matter hereof
and whether or not executed by Buyer and the Company.

                  IN WITNESS WHEREOF, the parties hereto have caused this
Agreement to be duly executed and delivered by the proper and duly authorized
officers as of the day and year first above written.

                                        /s/ H. WAYNE HUIZENGA
                                        ----------------------------------------
                                        H. Wayne Huizenga


                                        OHM CORPORATION


                                        By: /s/ RANDALL M. WALTERS
                                        ----------------------------------------
                                        Name: Randall M. Walters
                                        Title:   Vice President, General Counsel
                                                 and Secretary

                                       10


   52


                                   EXHIBIT "A"

                  [To be signed only upon exercise of Option]
To OHM Corporation:

                  The undersigned, the Holder of the within Option, hereby
irrevocably elects to exercise the purchase right represented by such Option
for, and to purchase thereunder, _____________ shares of the common stock, par
value $.10 per share, of OHM Corporation and herewith makes payment of
$___________ thereof or, and requests that the certificates for such shares be
issued in the name of, and be delivered to, ______________ whose address is
___________________________.

Dated:

____________________________

                            _______________________
                            (Signature must conform in all respects to name
                            of Holder as specified on the face of the Option)

                            _______________________
                            Address