<PAGE>   1


                                                                  EXHIBIT 2.1






















                                      40
<PAGE>   2
 
                           AGREEMENT AND PLAN OF MERGER
 
                           DATED AS OF FEBRUARY 20, 1998
 
                                   BY AND AMONG
 
                                HARSCO CORPORATION,
 
                             H-CHEMI ACQUISITION CORP.
 
                                        AND
 
                              CHEMI-TROL CHEMICAL CO.





                                      41
<PAGE>   3
 
                               TABLE OF CONTENTS
 
             This Table of Contents is not part of the Agreement to
           which it is attached but is inserted for convenience only.
 
<TABLE>
<CAPTION>
                                                              PAGE
                                                              NO.
                                                              ----
<S>                                                           <C>
ARTICLE I PLAN OF MERGER....................................    1
  1.01  The Merger..........................................    1
  1.02  Effective Time......................................    1
  1.03  Closing.............................................    1
  1.04  Articles of Incorporation; Bylaws of the Surviving
        Corporation; Location of Principal Office...........    1
  1.05  Directors and Officers of the Surviving
        Corporation.........................................    2
  1.06  Effects of the Merger...............................    2
  1.07  Further Assurances..................................    2
  1.08  Consent to be Sued and Served with Process..........    2
  1.09  Transaction of Business.............................    2
  1.10  Other Matters.......................................    2
ARTICLE II CONVERSION OF SHARES.............................    2
  2.01  Conversion of Capital Stock.........................    2
  2.02  Exchange of Certificates............................    3
ARTICLE III REPRESENTATIONS AND WARRANTIES OF THE COMPANY...    4
  3.01  Organization and Qualification......................    4
  3.02  Capital Stock.......................................    4
  3.03  Authority Relative to this Agreement and the Stock
        Option Agreement....................................    5
  3.04  Non-Contravention; Approvals and Consents...........    5
  3.05  SEC Reports and Financial Statements................    6
  3.06  Absence of Certain Changes or Events................    6
  3.07  Absence of Undisclosed Liabilities..................    7
  3.08  Legal Proceedings...................................    7
  3.09  Information Supplied................................    7
  3.10  Compliance with Laws and Orders.....................    7
  3.11  Compliance with Agreements; Certain Agreements......    8
  3.12  Taxes...............................................    8
  3.13  Benefit Plans; ERISA................................    9
  3.14  Insurance...........................................   11
  3.15  Labor Matters.......................................   11
  3.16  Environmental Matters...............................   12
  3.17  Tangible Property and Assets........................   13
  3.18  Intellectual Property Rights........................   14
  3.19  Vote Required.......................................   14
  3.20  Opinion of Financial Advisor........................   14
ARTICLE IV REPRESENTATIONS AND WARRANTIES OF HARSCO AND
  ACQUISITION SUB...........................................   14
  4.01  Organization and Qualification......................   14
  4.02  Authority Relative to this Agreement and the Stock
        Option Agreement....................................   14
  4.03  Non-Contravention; Approvals and Consents...........   15
  4.04  Legal Proceedings...................................   15
  4.05  Information Supplied................................   15
  4.06  Financing...........................................   16
</TABLE>
 



                                      42
<PAGE>   4
 
<TABLE>
<CAPTION>
                                                              PAGE
                                                              NO.
                                                              ----
<S>                                                           <C>
ARTICLE V COVENANTS OF THE COMPANY..........................   16
  5.01  Conduct of Business.................................   16
  5.02  No Solicitations....................................   17
ARTICLE VI ADDITIONAL AGREEMENTS............................   18
  6.01  Access to Information; Confidentiality..............   18
  6.02  Preparation of Proxy Statement......................   18
  6.03  Approval of Shareholders............................   19
  6.04  Regulatory and Other Approvals......................   19
  6.05  Benefit Plans.......................................   19
  6.06  Stock Option Agreement..............................   20
  6.07  Expenses............................................   20
  6.08  Brokers or Finders..................................   20
  6.09  Notice and Cure.....................................   20
  6.10  Fulfillment of Conditions...........................   21
  6.11  1997 Audited Financial Statements...................   21
ARTICLE VII CONDITIONS......................................   21
  7.01  Conditions to Each Party's Obligation to Effect the
        Merger..............................................   21
  7.02  Conditions to Obligation of Harsco and Acquisition
        Sub to Effect the Merger............................   21
  7.03  Conditions to Obligation of the Company to Effect
        the Merger..........................................   22
ARTICLE VIII TERMINATION, AMENDMENT AND WAIVER..............   23
  8.01  Termination.........................................   23
  8.02  Effect of Termination...............................   23
  8.03  Amendment...........................................   24
  8.04  Waiver..............................................   24
ARTICLE IX GENERAL PROVISIONS...............................   24
  9.01  Non-Survival of Representations, Warranties,
        Covenants and Agreements............................   24
  9.02  Knowledge...........................................   24
  9.03  Notices.............................................   24
  9.04  Entire Agreement....................................   25
  9.05  Public Announcements................................   25
  9.06  No Third Party Beneficiary..........................   25
  9.07  No Assignment; Binding Effect.......................   25
  9.08  Headings............................................   26
  9.09  Invalid Provisions..................................   26
  9.10  Governing Law.......................................   26
  9.11  Counterparts........................................   26
</TABLE>
 
EXHIBITS
 
EXHIBIT A  Opinion of Counsel to the Company
EXHIBIT B  Opinion of Counsel to Harsco and Acquisition Sub
 

                                      43
<PAGE>   5
 
     This AGREEMENT AND PLAN OF MERGER dated as of February 20, 1998 is made and
entered into by and among HARSCO CORPORATION, a Delaware corporation ("Harsco"),
H-CHEMI ACQUISITION CORP., a Pennsylvania corporation wholly owned by Harsco
("Acquisition Sub"), and CHEMI-TROL CHEMICAL CO., an Ohio corporation (the
"Company").
 
     WHEREAS, the Boards of Directors of Harsco, Acquisition Sub and the Company
have each determined that it is advisable and in the best interests of their
respective shareholders to consummate, and have approved, the business
combination transaction provided for herein in which Acquisition Sub would merge
with and into the Company and the Company would become a wholly-owned subsidiary
of Harsco (the "Merger"); and
 
     WHEREAS, concurrently with the execution and delivery of this Agreement and
as a condition and inducement to Harsco's and Acquisition Sub's willingness to
enter into this Agreement, the Company, Harsco and Acquisition Sub have entered
into a stock option agreement of even date herewith (the "Stock Option
Agreement") granting Acquisition Sub an option to purchase from the Company
190,468 authorized and unissued shares of Company Common Stock (as defined in
Section 2.01(b)), subject to the terms and conditions set forth therein; and
 
     WHEREAS, Harsco, Acquisition Sub and the Company desire to make certain
representations, warranties and agreements in connection with the Merger and
also to prescribe various conditions to the Merger;
 
     NOW, THEREFORE, in consideration of the mutual covenants and agreements set
forth in this Agreement, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree as follows:
 
                                   ARTICLE I
 
                                 PLAN OF MERGER
 
     1.01  The Merger.  At the Effective Time (as defined in Section 1.02), upon
the terms and subject to the conditions of this Agreement, Acquisition Sub shall
be merged with and into the Company in accordance with the General Corporation
Law of the State of Ohio (the "OGCL") and the Business Corporation Law of the
Commonwealth of Pennsylvania (the "PBCL"). The Company shall be the surviving
corporation in the Merger (the "Surviving Corporation"). Acquisition Sub and the
Company are sometimes referred to herein as the "Constituent Corporations." As a
result of the Merger, the outstanding shares of capital stock of the Constituent
Corporations shall be converted or canceled in the manner provided in Article
II.
 
     1.02  Effective Time.  At the Closing (as defined in Section 1.03), a
certificate of merger (the "Certificate of Merger") and articles of merger
("Articles of Merger") shall be duly prepared and executed by the Constituent
Corporations and thereafter delivered to the Secretary of State of the State of
Ohio (the "Ohio Secretary of State") for filing, as provided in Section 1701.81
of the OGCL, and the Secretary of State of the Commonwealth of Pennsylvania (the
"Pennsylvania Secretary of State") for filing, as provided in Section 1927 of
the PBCL, on, or as soon as practicable after, the Closing Date (as defined in
Section 1.03). The Merger shall become effective on the date the Certificate of
Merger and Articles of Merger are filed (the date so provided in the Certificate
of Merger being referred to herein as the "Effective Time").
 
     1.03  Closing.  The closing of the Merger (the "Closing") will take place
at the offices of Morgan, Lewis & Bockius LLP, One Commerce Square, 417 Walnut
Street, Harrisburg, Pennsylvania 17101, or at such other place as the parties
hereto mutually agree, on a date and at a time to be specified by the parties,
which shall in no event be later than 10:00 a.m., local time, on the 5th
business day following satisfaction of the condition set forth in Section
7.01(a), provided that the other closing conditions set forth in Article VII
have been satisfied or, if permissible, waived in accordance with this
Agreement, or on such other date as the parties hereto mutually agree (the
"Closing Date"). At the Closing there shall be delivered to Harsco, Acquisition
Sub and the Company the certificates and other documents and instruments
required to be delivered under Article VII.
 
     1.04  Articles of Incorporation; Bylaws of the Surviving Corporation;
Location of Principal Office.  At the Effective Time, (i) the Articles of
Incorporation of the Company as in effect immediately prior to the Effective
Time shall be amended so that such articles are identical (except for (i) the
name, which shall remain "Chemi-



                                      44
<PAGE>   6
 
Trol Chemical Co.", and (ii) the state of incorporation, which shall remain
Ohio, to the articles of incorporation of Acquisition Sub as in effect
immediately prior to the Effective Time, and, as so amended, such Articles of
Incorporation shall be the Articles of Incorporation of the Surviving
Corporation until thereafter amended as provided by law and such Articles of
Incorporation, and (ii) the Bylaws of Acquisition Sub as in effect immediately
prior to the Effective Time shall be the Regulations of the Surviving
Corporation until thereafter amended as provided by law, the Articles of
Incorporation of the Surviving Corporation and such Regulations. The location of
the principal office of the Surviving Corporation shall be 2776 Country Road 69,
Gibsonburg, OH 43431.
 
     1.05  Directors and Officers of the Surviving Corporation.  The directors
and the officers of the Company at or following the Effective Time, at the
request of Harsco, shall submit their resignations as of the Effective Time and
the persons appointed by Harsco, in its sole discretion, to be the directors and
officers of the Surviving Corporation shall be the directors and officers,
respectively, of the Surviving Corporation until their successors shall have
been duly elected or appointed and qualified or until their earlier death,
resignation or removal in accordance with the Surviving Corporation's Articles
of Incorporation and Regulations.
 
     1.06  Effects of the Merger.  Subject to the foregoing, the effects of the
Merger shall be as provided in the applicable provisions of the OGCL and the
PBCL.
 
     1.07  Further Assurances.  Each party hereto will execute such further
documents and instruments and take such further actions as may reasonably be
requested by one or more of the others to consummate the Merger, to vest the
Surviving Corporation with full title to all assets, properties, rights,
approvals, immunities and franchises of either of the Constituent Corporations
or to effect the other purposes of this Agreement.
 
     1.08  Consent to be Sued and Served with Process.  The Surviving
Corporation consents to be sued and served with process in the State of Ohio and
irrevocably appoints the Ohio Secretary of State as its agent to accept service
of process in any proceeding in the state and to enforce against the Surviving
Corporation any obligation of any Ohio domestic constituent corporation or to
enforce the rights of any holders of Dissenting Shares.
 
     1.09  Transaction of Business.  If Harsco exercises its rights under
Section 1.10 hereof, the Surviving Corporation shall transact business in the
State of Ohio as a foreign corporation and shall appoint a statutory agent with
respect to service of any process, notice or demand upon such statutory agent or
the Ohio Secretary of State, as required when a foreign corporation applies for
a license to transact business in the State of Ohio.
 
     1.10  Other Matters.  Notwithstanding any terms of this Agreement to the
contrary, Harsco shall have the right to cause Acquisition Sub to be the
Surviving Corporation of the Merger, so long as the exercise of such right does
not have a material adverse effect on the interests of the holders of the
Company's Common Stock in a manner which has not been disclosed to them in the
Proxy Statement (as defined herein at Section 3.09) or cause a material delay
in, or otherwise adversely affect, consummation of the transaction described
herein; if such right is exercised, this Agreement shall be deemed to be
modified to accord such change, including, without limitation, that the laws of
the Commonwealth of Pennsylvania, together with the OGCL, will govern the
Merger.
 
                                   ARTICLE II
 
                              CONVERSION OF SHARES
 
     2.01  Conversion of Capital Stock.  At the Effective Time, by virtue of the
Merger and without any action on the part of the holder thereof:
 
          (a) Capital Stock of Acquisition Sub. All of the issued and
     outstanding shares of the common stock, par value $.01 per share, of
     Acquisition Sub ("Acquisition Sub Common Stock") issued and outstanding
     immediately prior to the Effective Time shall remain outstanding and
     unchanged after the Merger and shall thereafter constitute all of the
     issued and outstanding shares of the capital stock of the Surviving
     Corporation ("Surviving Corporation Common Stock").
 
                                      45
<PAGE>   7
 
          (b)  Cancellation of Treasury Stock.  All shares of common stock,
     without par value, of the Company ("Company Common Stock") that are owned
     by the Company as treasury stock shall be canceled and retired and shall
     cease to exist and no stock of Harsco or other consideration shall be
     delivered in exchange therefor.
 
          (c)  Exchange Ratio for Company Common Stock.  Each issued and
     outstanding share of Company Common Stock (other than shares to be canceled
     in accordance with Section 2.01(b) and other than Dissenting Shares (as
     defined in Section 2.01(d))) shall be converted into the right to receive
     $23.00 in cash (the "Merger Price"). All such shares of Company Common
     Stock shall no longer be outstanding and shall automatically be canceled
     and retired and shall cease to exist, and each holder of a certificate
     representing any such shares shall cease to have any rights with respect
     thereto, except the right to receive the Merger Price per share, upon the
     surrender of such certificate in accordance with Section 2.02, without
     interest.
 
          (d)  Dissenting Shares.
 
             (i)  To the extent applicable, each outstanding share of Company
        Common Stock the holder of which has not voted in favor of the Merger,
        has perfected such holder's right to an appraisal of such holder's
        shares in accordance with the applicable provisions of the OGCL and has
        not effectively withdrawn or lost such right to appraisal (a "Dissenting
        Share"), shall not be converted into or represent a right to receive the
        Merger Price pursuant to Section 2.01(c), but the holder thereof shall
        be entitled only to such rights as are granted by the applicable
        provisions of the OGCL; provided, however, that any Dissenting Share
        held by a person at the Effective Time who shall, after the Effective
        Time, withdraw the demand for appraisal or lose the right of appraisal,
        in either case pursuant to the OGCL, shall be deemed to be converted
        into, as of the Effective Time, the right to receive the Merger Price
        pursuant to Section 2.01(c).
 
             (ii)  The Company shall give Harsco (x) prompt notice of any
        written demands for appraisal, withdrawals of demands for appraisal and
        any other instruments served pursuant to the applicable provisions of
        the OGCL relating to the appraisal process received by the Company and
        (y) the opportunity to direct all negotiations and proceedings with
        respect to demands for appraisal under the OGCL. The Company will not
        voluntarily make any payment with respect to any demands for appraisal
        and will not, except with the prior written consent of Harsco, settle or
        offer to settle any such demands.
 
     2.02  Exchange of Certificates.
 
          (a)  Exchange Agent.  At the Closing or immediately prior to the
     Effective Time, Harsco shall make available to the Surviving Corporation
     for deposit with The Fifth Third Bank of Northwestern Ohio, N.A., by Harsco
     (the "Exchange Agent"), a cash amount equal to the aggregate Merger Price
     to which holders of shares of Company Common Stock shall be entitled upon
     consummation of the Merger, to be held for the benefit of and distributed
     to such holders in accordance with this Section. The Exchange Agent shall
     agree to hold such funds (such funds, together with earnings thereon, being
     referred to herein as the "Exchange Fund") for delivery as contemplated by
     this Section and upon such additional terms as may be agreed upon by the
     Exchange Agent, the Company and Harsco.
 
          (b)  Exchange Procedures.  As soon as reasonably practicable after the
     Effective Time, the Surviving Corporation shall cause the Exchange Agent to
     mail to each holder of record of a certificate or certificates which
     immediately prior to the Effective Time represented outstanding shares of
     Company Common Stock (the "Certificates") whose shares are converted
     pursuant to Section 2.01(c) into the right to receive the Merger Price (i)
     a letter of transmittal (which shall specify that delivery shall be
     effected, and risk of loss and title to the Certificates shall pass, only
     upon delivery of the Certificates to the Exchange Agent and shall be in
     such form and have such other provisions as the Surviving Corporation may
     reasonably specify) and (ii) instructions for use in effecting the
     surrender of the Certificates in exchange for the Merger Price. Upon
     surrender of a Certificate for cancellation to the Exchange Agent, together
     with such letter of transmittal duly executed and completed in accordance
     with its terms, the holder of such Certificate shall be entitled to receive
     in exchange therefor a check representing the Merger Price per share of
     Company Common Stock represented thereby which such holder has the right to
     receive pursuant to the provisions of this Article II,
 
                                      46
<PAGE>   8
 
     and the Certificate so surrendered shall forthwith be canceled. In no event
     shall the holder of any Certificate be entitled to receive interest on any
     funds to be received in the Merger. In the event of a transfer of ownership
     of Company Common Stock which is not registered in the transfer records of
     the Company, the Merger Price may be issued to a transferee if the
     Certificate representing such Company Common Stock is presented to the
     Exchange Agent accompanied by all documents required to evidence and effect
     such transfer and by evidence that any applicable stock transfer taxes have
     been paid. Until surrendered as contemplated by this Section 2.02(b), each
     Certificate shall be deemed at any time after the Effective Time to
     represent only the right to receive upon such surrender the Merger Price
     per share of Company Common Stock represented thereby as contemplated by
     this Article II.
 
          (c)  No Further Ownership Rights in Company Common Stock.  All cash
     paid upon the surrender of shares of Company Common Stock in accordance
     with the terms hereof shall be deemed to have been paid in full
     satisfaction of all rights pertaining to such shares of Company Common
     Stock. From and after the Effective Time, the stock transfer books of the
     Company shall be closed and there shall be no further registration of
     transfers on the stock transfer books of the Surviving Corporation of the
     shares of Company Common Stock which were outstanding immediately prior to
     the Effective Time. If, after the Effective Time, Certificates are
     presented to the Surviving Corporation for any reason, they shall be
     canceled and exchanged as provided in this Section.
 
          (d)  Termination of Exchange Fund.  Any portion of the Exchange Fund
     which remains undistributed to the shareholders of the Company twenty-four
     (24) months after the Effective Time shall be delivered to the Surviving
     Corporation, upon demand, and any shareholders of the Company who have not
     theretofore complied with this Article II shall thereafter look only to the
     Surviving Corporation (subject to abandoned property, escheat and other
     similar laws) as general creditors for payment of their claim for the
     Merger Price per share. Neither Harsco nor the Surviving Corporation shall
     be liable to any holder of shares of Company Common Stock for cash
     representing the Merger Price delivered to a public official pursuant to
     any applicable abandoned property, escheat or similar law.
 
                                  ARTICLE III
 
                 REPRESENTATIONS AND WARRANTIES OF THE COMPANY
 
     The Company represents and warrants to Harsco and Acquisition Sub as
follows:
 
     3.01  Organization and Qualification.  The Company is a corporation duly
organized, validly existing and in good standing under the laws of its
jurisdiction of incorporation and has full corporate power and authority to
conduct its business as and to the extent now conducted and to own, use and
lease its assets and properties. The Company is duly qualified, licensed or
admitted to do business and is in good standing in each jurisdiction listed on
Schedule 3.01 hereto in which the ownership, use or leasing of its assets and
properties, or the conduct or nature of its business, makes such qualification,
licensing or admission necessary, except for such failures to be so qualified,
licensed or admitted and in good standing which, individually or in the
aggregate, (i) are not having and could not be reasonably expected to have a
material adverse effect on the Company, and (ii) could not be reasonably
expected to have a material adverse effect on the validity or enforceability of
this Agreement or the Stock Option Agreement or on the ability of the Company to
perform its obligations hereunder or thereunder. As used in this Agreement, any
reference to any event, change or effect being "material" or "materially
adverse" or having a "material adverse effect" on or with respect to an entity
(or group of entities taken as a whole) means such event, change or effect is
material or materially adverse, as the case may be, to the business, condition
(financial or otherwise), properties, assets (including intangible assets),
liabilities (including contingent liabilities), prospects or results of
operations of such entity (or, if with respect thereto, of such group of
entities taken as a whole). The Company does not directly or indirectly own any
equity or similar interest in, or any interest convertible into or exchangeable
or exercisable for, any equity or similar interest in, any corporation,
partnership, joint venture or other business association or entity.
 
     3.02  Capital Stock.  (a) The authorized capital stock of the Company
consists solely of 6,000,000 shares of Company Common Stock. As of the date
hereof, 2,004,930 shares of Company Common Stock were issued
 
                                      47
<PAGE>   9
 
and outstanding, and 0 shares were held in the treasury of the Company. There
has been no change in the number of issued and outstanding shares of Company
Common Stock or shares of Company Common Stock held in the treasury since such
date other than the reservation of 190,468 shares pursuant to the Stock Option
Agreement. All of the issued and outstanding shares of Company Common Stock are,
and all shares reserved for issuance will be, upon issuance in accordance with
the terms specified in the instruments or agreements pursuant to which they are
issuable, duly authorized, validly issued, fully paid and nonassessable. Except
pursuant to this Agreement and the Stock Option Agreement, there are no
outstanding subscriptions, options, warrants, rights (including "phantom" stock
rights), preemptive rights or other contracts, commitments, understandings or
arrangements, including any right of conversion or exchange under any
outstanding security, instrument or agreement (together, "Options"), obligating
the Company to issue or sell any shares of capital stock of the Company or to
grant, extend or enter into any Option with respect thereto.
 
          (b)  There are no outstanding contractual obligations of the Company
     to repurchase, redeem or otherwise acquire any shares of Company Common
     Stock or to provide funds to, or make any investment (in the form of a
     loan, capital contribution or otherwise) in any other person.
 
     3.03  Authority Relative to this Agreement and the Stock Option
Agreement.  The Company has full corporate power and authority to enter into
this Agreement and the Stock Option Agreement and, subject (in the case of this
Agreement) to obtaining the Company Shareholders' Approval (as defined in
Section 6.03), to perform its obligations hereunder and thereunder and to
consummate the transactions contemplated hereby and thereby. The execution,
delivery and performance of this Agreement and the Stock Option Agreement by the
Company and the consummation by the Company of the transactions contemplated
hereby and thereby have been duly and validly approved by the Board of Directors
of the Company, the Board of Directors of the Company has recommended adoption
of this Agreement by the shareholders of the Company and directed that this
Agreement be submitted to the shareholders of the Company for their
consideration, and no other corporate proceedings on the part of the Company or
its shareholders are necessary to authorize the execution, delivery and
performance of this Agreement and the Stock Option Agreement by the Company and
the consummation by the Company of the transactions contemplated hereby and
thereby, other than obtaining the Company Shareholders' Approval. This Agreement
and the Stock Option Agreement have been duly and validly executed and delivered
by the Company and, subject (in the case of this Agreement) to the obtaining of
the Company Shareholders' Approval, constitute legal, valid and binding
obligations of the Company enforceable against the Company in accordance with
their terms, except as enforceability may be limited by bankruptcy, insolvency,
reorganization, moratorium or other similar laws affecting the enforcement of
creditors' rights generally and by general equitable principles (regardless of
whether such enforceability is considered in a proceeding in equity or at law).
 
     3.04  Non-Contravention; Approvals and Consents.
 
          (a)  The execution and delivery of this Agreement and the Stock Option
     Agreement by the Company do not, and the performance by the Company of its
     obligations hereunder and thereunder and the consummation of the
     transactions contemplated hereby and thereby will not, conflict with,
     result in a violation or breach of, constitute (with or without notice or
     lapse of time or both) a default under, result in or give to any person any
     right of payment or reimbursement, termination, cancellation, modification
     or acceleration of, or result in the creation or imposition of any liens,
     claims, mortgages, encumbrances, pledges, security interests, equities and
     charges of any kind (each a "Lien") upon any of the assets or properties of
     the Company under, any of the terms, conditions or provisions of (i) the
     articles of incorporation or regulations (or other comparable charter
     documents) of the Company, or (ii) subject to the obtaining of the Company
     Shareholders' Approval and the taking of the actions described in paragraph
     (b) of this Section, (x) any statute, law, rule, regulation or ordinance
     (together, "Laws"), or any judgment, decree, order, writ, permit or license
     (together, "Orders"), of any court, tribunal, arbitrator, authority,
     agency, commission, official or other instrumentality of the United States,
     any foreign country or any domestic or foreign state, county, city or other
     political subdivision (a "Governmental or Regulatory Authority"),
     applicable to the Company or any of its assets or properties, or (y) any
     note, bond, mortgage, security agreement, indenture, license, franchise,
     permit, concession, contract, lease or other instrument, obligation or
     agreement of any kind (together, "Contracts") to which the Company is a
     party or by which the Company or any of its assets or properties is bound,
     excluding from the foregoing clauses (x) and (y)
 
                                      48
<PAGE>   10
 
     conflicts, violations, breaches, defaults, terminations, modifications,
     accelerations and creations and impositions of Liens which, individually or
     in the aggregate, could not be reasonably expected to have a material
     adverse effect on the Company taken as a whole or on the ability of the
     Company to consummate the transactions contemplated by this Agreement and
     the Stock Option Agreement.
 
          (b)  Except (i) for the filing of a premerger notification report by
     the Company under the Hart-Scott-Rodino Antitrust Improvements Act of 1976,
     as amended, and the rules and regulations thereunder (the "HSR Act"), (ii)
     for the filing of the Proxy Statement (as defined in Section 3.09) with the
     Securities and Exchange Commission (the "SEC") pursuant to the Securities
     Exchange Act of 1934, as amended, and the rules and regulations thereunder
     (the "Exchange Act"), (iii) for the filing of the Certificate of Merger,
     the Articles of Merger and other appropriate merger documents required by
     the OGCL and the PBCL with the Ohio Secretary of State and the Pennsylvania
     Secretary of State and appropriate documents with the relevant authorities
     of other states in which the Constituent Corporations are qualified to do
     business, and (iv) as disclosed in Schedule 3.04 hereto, no consent,
     approval or action of, filing with or notice to any Governmental or
     Regulatory Authority or other public or private third party is necessary or
     required under any of the terms, conditions or provisions of any Law or
     Order of any Governmental or Regulatory Authority or any Contract to which
     the Company is a party or by which the Company or any of its assets or
     properties is bound for the execution and delivery of this Agreement and
     the Stock Option Agreement by the Company, the performance by the Company
     of its obligations hereunder and thereunder or the consummation of the
     transactions contemplated hereby and thereby, other than such consents,
     approvals, actions, filings and notices which the failure to make or
     obtain, as the case may be, individually or in the aggregate, could not be
     reasonably expected to have a material adverse effect on the Company or on
     the ability of the Company to consummate the transactions contemplated by
     this Agreement and the Stock Option Agreement.
 
     3.05  SEC Reports and Financial Statements.  The Company delivered to
Harsco prior to the execution of this Agreement a true and complete copy of each
form, report, schedule, registration statement, definitive proxy statement and
other document (together with all amendments thereof and supplements thereto)
filed by the Company with the SEC since December 2, 1997 (as such documents have
since the time of their filing been amended or supplemented, the "Company SEC
Reports"), which are all the documents (other than preliminary material) that
the Company was required to file with the SEC since such date. As of their
respective dates, the Company SEC Reports (i) complied as to form in all
material respects with the requirements of the Securities Act of 1933, as
amended, and the rules and regulations thereunder (the "Securities Act"), or the
Exchange Act, as the case may be, and (ii) did not contain any untrue statement
of a material fact or omit to state a material fact required to be stated
therein or necessary in order to make the statements therein, in light of the
circumstances under which they were made, not misleading. The audited financial
statements and unaudited interim financial statements (including, in each case,
the notes, if any, thereto) included in the Company SEC Reports (the "Company
Financial Statements") complied as to form in all material respects with the
published rules and regulations of the SEC with respect thereto, were prepared
in accordance with generally accepted accounting principles ("GAAP") applied on
a consistent basis during the periods involved (except as may be indicated
therein or in the notes thereto and except with respect to unaudited statements
as permitted by Form 10-Q of the SEC) and fairly present (subject, in the case
of the unaudited interim financial statements, to normal, recurring year-end
audit adjustments which are not expected to be, individually or in the
aggregate, materially adverse to the Company) the financial position of the
Company as at the respective dates thereof and the results of its operations and
cash flows for the respective periods then ended.
 
     3.06  Absence of Certain Changes or Events.  Except as disclosed Schedule
3.06 hereto, (a) since September 30, 1997 there has not been any change, event
or development having, or that could be reasonably expected to have,
individually or in the aggregate, a material adverse effect on the Company,
other than those occurring as a result of general economic or financial
conditions or other developments which are not unique to the Company but also
generally affect other persons who participate or are engaged in the lines of
business in which the Company participates or is engaged, and (b) except as
disclosed in Schedule 3.06 hereto, between such date and the date hereof (i) the
Company has conducted its business only in the ordinary course consistent with
 
                                      49
<PAGE>   11
 
past practice and (ii) the Company has not taken any action which, if taken
after the date hereof, would constitute a breach of any provision of clause (ii)
of Section 5.01(b).
 
     3.07  Absence of Undisclosed Liabilities.  Except for matters reflected or
reserved against in the balance sheet dated September 30, 1997 included in the
Company Financial Statements or as disclosed in Schedule 3.07 hereto, the
Company has not at such date, or has not incurred since that date, any
liabilities or obligations of any nature that would be required by generally
accepted accounting principles to be reflected on a balance sheet of the Company
(including the notes thereto), except liabilities or obligations (i) which were
incurred in the ordinary course of business consistent with past practice and
(ii) which have not been, and could not be reasonably expected to be,
individually or in the aggregate, materially adverse to the Company.
 
     3.08  Legal Proceedings.  Except as disclosed in Schedule 3.08 hereto, (i)
there are no actions, suits, arbitrations or proceedings pending or, to the
knowledge of the Company, threatened against, relating to or affecting, nor to
the knowledge of the Company are there any Governmental or Regulatory Authority
investigations or audits pending or threatened against, relating to or
affecting, the Company or any of its assets and properties which, individually
or in the aggregate, could be reasonably expected to have a material adverse
effect on the Company or on the ability of the Company to consummate the
transactions contemplated by this Agreement or the Stock Option Agreement, and
there are no facts or circumstances known to the Company that could be
reasonably expected to give rise to any such action, suit, arbitration,
proceeding, investigation or audit, and (ii) the Company is not subject to any
Order of any Governmental or Regulatory Authority which, individually or in the
aggregate, is having or could be reasonably expected to have a material adverse
effect on the Company or on the ability of the Company to consummate the
transactions contemplated by this Agreement or the Stock Option Agreement.
 
     3.09  Information Supplied.  (a) The proxy statement relating to the
Company Shareholders' Meeting (as defined in Section 6.03), as amended or
supplemented from time to time (as so amended and supplemented, the "Proxy
Statement"), and any other documents to be filed by the Company with the SEC or
any other Governmental or Regulatory Authority in connection with the Merger and
the other transactions contemplated hereby or by the Stock Option Agreement will
not, on the date of its filing or, in the case of the Proxy Statement, at the
date it is mailed to shareholders, and at the time of the Company Shareholders'
Meeting and at the Effective Time, contain any untrue statement of a material
fact or omit to state any material fact required to be stated therein or
necessary in order to make the statements therein, in light of the circumstances
under which they are made, not misleading, except that no representation is made
by the Company with respect to information supplied in writing by or on behalf
of Harsco and Acquisition Sub expressly for inclusion therein and information
incorporated by reference therein from documents filed by Harsco or any of its
Subsidiaries with the SEC. The Proxy Statement and any such other documents
filed by the Company with the SEC under the Exchange Act will comply as to form
in all material respects with the requirements of the Exchange Act. As used in
this Agreement, "Subsidiary" means, with respect to any party, any corporation
or other organization, whether incorporated or unincorporated, of which more
than fifty percent (50%) of either the equity interests in, or the voting
control of, such corporation or other organization is, directly or indirectly
through Subsidiaries or otherwise, beneficially owned by such party.
 
          (b)  Neither the information supplied or to be supplied in writing by
     or on behalf of the Company for inclusion in any document to be filed by
     Harsco or Acquisition Sub with the SEC or any other Governmental or
     Regulatory Authority in connection with the Merger and the other
     transactions contemplated hereby or by the Stock Option Agreement will on
     the date of its filing contain any untrue statement of a material fact or
     omit to state any material fact required to be stated therein or necessary
     in order to make the statements therein, in light of the circumstances
     under which they are made, not misleading.
 
     3.10  Compliance with Laws and Orders. The Company holds all permits,
licenses, variances, exemptions, orders and approvals of all Governmental and
Regulatory Authorities necessary for the lawful conduct of its business (the
"Company Permits"), except for failures to hold such permits, licenses,
variances, exemptions, orders and approvals which, individually or in the
aggregate, are not having and could not be reasonably expected to have a
material adverse effect on the Company. The Company is in compliance with the
terms of the Company Permits, except failures so to comply which, individually
or in the aggregate, are not having and could not be
 
                                      50
<PAGE>   12
 
reasonably expected to have a material adverse effect on the Company. Except as
set forth in Schedule 3.10,the Company is not in violation of or default under
any Law or Order of any Governmental or Regulatory Authority, except for
violations which, individually or in the aggregate, are not having and could not
be reasonably expected to have a material adverse effect on the Company.
 
     3.11  Compliance with Agreements; Certain Agreements.
 
          (a) Except as disclosed in Schedule 3.11 hereto, neither the Company
     nor, to the knowledge of the Company, any other party thereto, is in breach
     or violation of, or in default in the performance or observance of any term
     or provision of, and no event has occurred which, with notice or lapse of
     time or both, could be reasonably expected to result in a default under,
     (i) the articles of incorporation or regulations (or other comparable
     charter documents) of the Company or (ii) any Contract to which the Company
     is a party or by which the Company or any of its assets or properties is
     bound, except in the case of clause (ii) for breaches, violations and
     defaults which, individually or in the aggregate, are not having and could
     not be reasonably expected to have a material adverse effect on the
     Company.
 
          (b) Except as disclosed in Schedule 3.11 hereto, as of the date
     hereof, the Company is not a party to any oral or written (i) consulting
     agreement not terminable on 30 days' or less notice involving the payment
     of more than $25,000 per annum or $100,000 per annum in the aggregate for
     all such agreements, (ii) union or collective bargaining agreement, (iii)
     agreement with any executive officer or other key employee of the Company
     the benefits of which are contingent or vest, or the terms of which are
     materially altered, upon the occurrence of a transaction involving the
     Company of the nature contemplated by this Agreement, (iv) agreement with
     respect to any executive officer or other key employee of the Company
     providing any term of employment or compensation guarantee extending for a
     period longer than 3 years and for the payment of more than $200,000 per
     annum or $500,000 per annum in the aggregate for all such agreements or (v)
     agreement or plan, including any stock option, stock appreciation right,
     restricted stock or stock purchase plan, any of the benefits of which will
     be increased, or the vesting of the benefits of which will be accelerated,
     by the occurrence of any of the transactions contemplated by this Agreement
     or the value of any of the benefits of which will be calculated on the
     basis of any of the transactions contemplated by this Agreement.
 
     3.12  Taxes.
 
          (a) The Company has filed all federal and all material foreign, state
     and local tax reports and returns required to be filed and except as
     disclosed on Schedule 3.12, has duly paid all such taxes, including,
     without limitation, income, capital stock, gross receipts, net proceeds, ad
     valorem, value added, turnover, sales, use, real estate transfer, property,
     personal property (tangible and intangible), stamp, leasing, lease, user,
     excise, franchise, transfer, fuel, vehicle sales, excess profits,
     occupational and interest equalization, unitary, severance, withholding,
     social security, employment and other taxes, duties, assessments and
     charges (including, without limitation, the recapture of any tax items such
     as investment tax credits), together with all interest, penalties and
     additions imposed with respect to such amounts, which are due on or before
     the date hereof or claimed to be due by federal, state, or local taxing
     authorities or which are payable on or before the date hereof with respect
     to the business and operations of the Company (collectively, "Taxes"). All
     such returns are accurate and complete in all material respects. There are
     no tax liens upon any property or assets of the Company, except liens for
     Taxes not yet due and payable. All such Taxes (including interest and
     penalties) applicable for all periods prior to the Closing or other
     governmental charges upon the Company or its assets, income or revenues
     have been or will be paid (if due) or reserved against if required under
     GAAP. The Company has not executed any waivers of the statute of
     limitations on the right of the Internal Revenue Service (the "IRS") or any
     state or local taxing authority to assess additional Taxes or to contest
     the income or loss with respect to any tax return. The basis of any
     depreciable assets, and the methods used in determining allowable
     depreciation (including cost recovery), held by the Company, are
     substantially correct and in compliance with the Internal Revenue Code of
     1986, as amended (the "Code"), and all regulations thereunder.
 
          (b) No issues have been raised that are currently pending by any
     taxing authority in connection with any of the aforesaid tax returns or
     reports. No issues have been raised in any examination by any taxing
 
                                      51
<PAGE>   13
 
     authority with respect to the Company which, by application of similar
     principles, reasonably could be expected to result in a material proposed
     deficiency for any other period not so examined. The items of income and
     deductions reflected on the federal income tax returns and comparable state
     and local returns filed by or on behalf of the Company for all taxable
     years (including the supporting schedules filed therewith), available
     copies of which have been supplied (or will be promptly supplied upon
     request) to Harsco, state accurately in all material respects the receipts
     and expenditures of the Company, and the same were derived from the books
     and records of the Company.
 
          (c) The Company has not entered into any joint venture, partnership,
     or other arrangement or contract which is treated as a partnership for
     federal income tax purposes, except as set forth on Schedule 3.12.
 
           The Company has never been a "consenting corporation," within the
     meaning of Section 341(f)(l) of the Code, or comparable provisions of any
     state statutes, and none of the assets of the Company is subject to an
     election under Section 341(f) of the Code or comparable provisions of any
     state statutes.
 
          (e) No property of the Company is property which the Company or Harsco
     is or will be required to treat as being owned by another person pursuant
     to the provisions of Section 168(f)(8) of the Code, as in effect prior to
     the Tax Reform Act of 1986, or pursuant to any provision of law.
 
          (f) No property of the Company is "tax exempt use property" as such
     term is defined in Section 168(h) of the Code.
 
          (g) None of the properties or assets of the Company is tax-exempt bond
     financed property within the meaning of Section 168(g)(5) of the Code,
     except as disclosed on Schedule 3.12.
 
          (h) Neither the Company nor any predecessor thereof is or has been, or
     has filed a tax return claiming that it is or has been, an Electing Small
     Business Corporation pursuant to the provisions of Subchapter S of the
     Code.
 
     3.13  Benefit Plans; ERISA.
 
          (a) All Benefit Plans are listed in Schedule 3.13, and copies of all
     documentation relating to such Benefit Plans have been delivered or made
     available to Harsco (including copies of written Benefit Plans, written
     descriptions of oral Benefit Plans, summary plan descriptions, trust
     agreements, the three most recent annual returns, employee communications,
     and IRS determination letters). Except as disclosed in Schedule 3.13
     hereto:
 
             (i) each Benefit Plan has at all times been maintained and
        administered in all material respects in accordance with its terms and
        with the requirements of all applicable law, including ERISA and the
        Code, and each Benefit Plan intended to qualify under Section 401(a) of
        the Code has at all times since its adoption been so qualified, and each
        trust which forms a part of any such plan has at all times since its
        adoption been tax-exempt under Section 501(a) of the Code;
 
             (ii) no Benefit Plan has incurred any "accumulated funding
        deficiency" within the meaning of Section 302 of ERISA or Section 412 of
        the Code;
 
             (iii) the "amount of unfunded benefit liabilities" within the
        meaning of Section 4001(a)(18) of ERISA does not exceed zero with
        respect to any Benefit Plan subject to Title IV of ERISA;
 
             (iv) no "reportable event" (within the meaning of Section 4043 of
        ERISA) has occurred with respect to any Benefit Plan or any Plan
        maintained by an ERISA Affiliate since the effective date of Section
        4043;
 
             (v) with respect to each Multiemployer Plan (i) no withdrawal
        liability has been incurred by the Company or any ERISA Affiliate , and
        the Company has no reason to believe that any such liability will be
        incurred, prior to the Closing Date, (ii) no such plan is in
        "reorganization" (within the meaning of Section 4241 of ERISA), (iii) no
        notice has been received that increased contributions may be required to
        avoid a reduction in plan benefits or the imposition of an excise tax,
        or that the plan is or may become "insolvent" (within the meaning of
        Section 4241 of ERISA), (iv) no proceedings have been instituted by the
        Pension Benefit Guaranty Corporation against the plan, (v) there is no
        contingent
 
                                      52
<PAGE>   14
 
        liability for withdrawal liability by reason of a sale of assets
        pursuant to Section 4204 of ERISA, and (vi) except as disclosed in
        Schedule 3.13, if the Company or any ERISA Affiliate were to have a
        complete or partial withdrawal under Section 4203 of ERISA as of the
        Closing, no obligation to pay withdrawal liability would exist on the
        part of the Company or any ERISA Affiliate;
 
             (vi) no direct, contingent or secondary liability has been incurred
        or is expected to be incurred by the Company under Title IV of ERISA to
        any party with respect to any Benefit Plan or Multiemployer Plan, or
        with respect to any other Plan presently or heretofore maintained or
        contributed to by any ERISA Affiliate;
 
             (vii) neither the Company nor any ERISA Affiliate has incurred any
        liability for any tax imposed under Section 4971 through 4980B of the
        Code or civil liability under Section 502(i) or (l) of ERISA;
 
             (viii) no benefit under any Benefit Plan, including, without
        limitation, any severance or parachute payment plan or agreement, will
        be established or become accelerated, vested or payable by reason of any
        transaction contemplated under this Agreement;
 
             (ix) no tax has been incurred under Section 511 of the Code with
        respect to any Benefit Plan (or trust or other funding vehicle pursuant
        thereto);
 
             (x) no Benefit Plan provides health or death benefit coverage
        beyond the termination of an employee's employment, except as required
        by Part 6 of Subtitle B of Title I of ERISA or Section 4980B of the Code
        or any State laws requiring continuation of benefits coverage following
        termination of employment;
 
             (xi) no suit, actions or other litigation (excluding claims for
        benefits incurred in the ordinary course of plan activities) have been
        brought or, to the knowledge of the Company, threatened against or with
        respect to any Benefit Plan and there are no facts or circumstances
        known to the Company that could reasonably be expected to give rise to
        any such suit, action or other litigation; and
 
             (xii) all contributions to Benefit Plans and Multiemployer Plans
        that were required to be made under such Benefit Plans have been made,
        and all benefits accrued under any unfunded Benefit Plan have been paid,
        accrued or otherwise adequately reserved in accordance with GAAP, all of
        which accruals under unfunded Benefit Plans are as disclosed in Schedule
        3.13, and the Company has performed all material obligations required to
        be performed under all Benefit Plans.
 
          (b) Except as set forth in Schedule 3.13 hereto, neither the execution
     and delivery of this Agreement nor the consummation of the transaction
     contemplated hereby constitutes a change of control or has or will
     accelerate benefits under any Benefit Plan.
 
          (c) As used herein:
 
             (i) "Benefit Plan" means any Plan, existing at the Closing Date or
        prior thereto, established or to which contributions have at any time
        been made by the Company, or any predecessor of the foregoing, or under
        which any employee, former employee or director of the Company or any
        beneficiary thereof is covered, is eligible for coverage or has benefit
        rights.
 
             (ii) "ERISA" means the Employee Retirement Income Security Act of
        1974, as amended, and the rules and regulations promulgated thereunder.
 
             (iii) "ERISA Affiliate" means any business entity which is, or at
        any time was, a member of a controlled group (within the meaning of
        Section 412(n)(6) of the Code) that includes, or at any time included,
        the Company or any predecessor of the foregoing.
 
             (iv) "Multiemployer Plan" means a multiemployer plan within the
        meaning of Section 4001(a)(3) of ERISA with respect to which the Company
        or any ERISA Affiliate has an obligation to contribute or has or could
        have withdrawal liability under Section 4201 of ERISA.
 
             (v) "Plan" means any bonus, incentive compensation, deferred
        compensation, pension, profit sharing, retirement, stock purchase, stock
        option, stock ownership, stock appreciation rights, phantom
 
                                      53
<PAGE>   15
 
        stock, leave of absence, layoff, vacation, day or dependent care, legal
        services, cafeteria, life, health, accident, disability, workmen's
        compensation or other insurance, severance, separation or other employee
        benefit plan, practice, policy or arrangement of any kind, whether
        written or oral, or whether for the benefit of a single individual or
        more than one individual including, but not limited to, any "employee
        benefit plan" within the meaning of Section 3(3) of ERISA.
 
     3.14  Insurance. The Company delivered to Harsco prior to the execution of
this Agreement a true and complete list of all liability, property, workers'
compensation, directors' and officers' liability and other insurance policies
currently in effect that insure the business, operations, properties, assets or
employees of the Company.
 
     3.15  Labor Matters.
 
          (a) Except as set forth in Schedule 3.15, (i) no employees of the
     Company or any affiliated enterprise of the Company ("Affiliate") are
     represented by a labor union or organization, no labor union or
     organization has been certified or recognized as a representative of any
     such employees, and neither the Company nor any Affiliate of the Company is
     a party to or has any obligation under any collective bargaining agreement
     or other labor union contract, white paper or side agreement with any labor
     union or organization, or has any obligation to recognize or deal with any
     labor union or organization, and there are no such contracts, white papers
     or side agreements pertaining to or which determine the terms or conditions
     of employment of any employee of the Company or any Affiliate of the
     Company; (ii) there are no pending or threatened representation campaigns,
     elections or proceedings or questions concerning union representation
     involving any employees of the Company or any Affiliate of the Company;
     (iii) neither the Company nor any Affiliate of the Company has any
     knowledge of any activities or efforts of any labor union or organization
     (or representatives thereof) to organize any employees of the Company or
     any Affiliate of the Company, nor of any demands for recognition or
     collective bargaining, nor of any strikes, slowdowns, work stoppages or
     lock-outs of any kind, or threats thereof, by or with respect to any
     employees of the Company or any Affiliate of the Company or any actual or
     claimed representatives thereof, and no such activities, efforts, demands,
     strikes, slowdowns, work stoppages or lock-outs occurred during the
     24-month period preceding the date hereof; (iv) neither the Company nor any
     Affiliate of the Company has engaged in, admitted committing or been held
     in any administrative or judicial proceeding to have committed any unfair
     labor practice under the National Labor Relations Act, as amended; (v)
     neither the Company nor any Affiliate of the Company is involved in any
     industrial or trade dispute or any dispute or negotiations regarding a
     claim of material importance with any labor union or organization; and (vi)
     there are no controversies, claims, demands or grievances of material
     importance pending or, so far as the Company or any Affiliate of the
     Company is aware, threatened, between the Company or any Affiliate of the
     Company and any of their respective employees or any actual or claimed
     representative thereof. The Company agrees to take such action as shall be
     required to fulfill any and all contractual or statutory obligations it or
     any Affiliate of the Company may have to any unions or labor organizations
     or otherwise as a result of or relating to the execution and delivery of
     this Agreement and the consummation of the transactions contemplated
     hereby.
 
          (b) Schedule 3.15 (and the exhibits thereto) set forth all contracts
     and agreements, including, without limitation, employment agreements,
     consulting agreements, independent contractor agreements, retainers and
     severance agreements under which the Company or any Affiliate of the
     Company has any obligation to provide wages, salary, commissions, or other
     compensation or remuneration (other than obligations to make current wage
     or salary payments terminable at will without notice) to or on behalf of
     any employee, former employee, consultant or contractor (or any designee,
     assignee or beneficiary thereof). The original or a complete and correct
     copy of each written (and a complete and correct written description of
     each such oral) contract or agreement, has been delivered or made available
     to Harsco.
 
          (c) A true and correct statement of the names, current rates of base
     compensation and amounts of (or, where no amount is specified, the formula
     for computing) supplemental or bonus compensation of all officers,
     directors and employees of the Company and Affiliates of the Company as of
     the date hereof, is set forth in Schedule 3.15. Except as set forth in
     Schedule 3.15, (i) the Company and Affiliates of the Company have no
     obligation (including an obligation for the payment of any fee,
     extraordinary bonus, or "golden parachute" based upon the successful
     completion of the transactions contemplated hereunder) under any
 
                                      54
<PAGE>   16
 
     employment contract, consulting agreement, or any other similar agreements,
     employment policies (including vacation and severance pay policies) or
     retirement or employee benefit plans, arrangements or understandings,
     written or otherwise, with any officer, director, employee or agent of the
     Company or any Affiliate and (ii) since January 1, 1998, the Company and
     the Affiliates have (A) not paid or agreed to pay any bonuses or made or
     agreed to make any increase in the rate of wages, salaries or other
     compensation or remuneration of any of its officers, directors, consultants
     or employees (except for increases in accordance with written binding
     commitments, true, correct and complete copies of which have been
     previously delivered to Harsco, or in accordance with a past practice
     described in Schedule 3.15), or (B) become a party to any employment
     contract or arrangement with any of its officers or employees providing for
     any new or additional bonuses, profit sharing payments, severance pay or
     retirement benefits or any other form of employee compensation or benefits.
 
          (d) The Company and each Affiliate of the Company has at all times
     complied in all material respects and is in material compliance with all
     applicable federal, state, and local laws, rules and regulations respecting
     employment, wages, hours, compensation, benefits, occupational health and
     safety, and payment and withholding of taxes in connection with employment.
     The Company and each Affiliate of the Company has withheld all amounts
     required by law or agreement to be withheld from wages, salaries,
     commissions, etc., and neither the Company nor any Affiliate of the Company
     is liable for any arrears of wages or any taxes or penalties for failure to
     comply with any of the foregoing. There are no claims, complaints or legal
     or administrative proceedings pending or, so far as the Company and any
     Affiliate of the Company is aware, threatened, against the Company or any
     Affiliate of the Company before any federal, state or municipal court or
     governmental agency, or any federal, state or municipal taxing authority
     involving or relating to any past or present employee(s) or applicant(s)
     for employment of the Company or any Affiliate of the Company, or relating
     to any acts, omissions or practices of the Company or any Affiliate of the
     Company relating to employment, compensation or benefits. Neither the
     Company nor any Affiliate of the Company is party to or bound by any court
     or administrative order, judgment, decree or ruling of any kind respecting
     the employment, compensation or benefits of any employees or prospective
     employees of the Company or any Affiliate of the Company.
 
     3.16 Environmental Matters. Except as disclosed in Schedule 3.16 hereto, to
the best of the Company's knowledge:
 
          (a) The Company has obtained all licenses, permits, authorizations,
     approvals and consents from Governmental or Regulatory Authorities which
     are required in respect of its business, operations, assets or properties
     under any applicable Environmental Law (as defined below). The Company is
     in compliance in all material respects with the terms and conditions of all
     such licenses, permits, authorizations, approvals and consents and with any
     applicable Environmental Law.
 
          (b) No Order has been issued, no complaint has been filed, no penalty
     has been assessed and no investigation or review is pending or threatened
     by any Governmental or Regulatory Authority with respect to any alleged
     failure by the Company to have any license, permit, authorization, approval
     or consent from Governmental or Regulatory Authorities required under any
     applicable Environmental Law in connection with the conduct of the business
     or operations of the Company or with respect to any treatment, storage,
     recycling, transportation, disposal or "release" as defined in 42 U.S.C.
     sec.9601(22) ("Release"), by the Company of any Hazardous Material (as
     defined below), which Order, complaint, penalty or investigation,
     individually or in the aggregate, is having or could be reasonably expected
     to have a material adverse effect on the Company, and the Company is not
     aware of any facts or circumstances which could be reasonably expected to
     form the basis for any such Order, complaint, penalty or investigation.
 
          (c) Neither the Company nor any prior owner or lessee of any property
     now or previously owned or leased by the Company has handled any Hazardous
     Material on any property now or previously owned or leased by the Company;
     and, without limiting the foregoing, (i) no polychlorinated biphenyl is or
     has been present, (ii) no asbestos is or has been present, (iii) there are
     no underground storage tanks, active or abandoned and (iv) no Hazardous
     Material has been Released in a quantity reportable under, or in violation
     of, any Environmental Law, at, on or under any property now or previously
     owned or leased by the
 
                                      55
<PAGE>   17
 
     Company, during any period that the Company owned or leased such property
     and which could reasonably be expected to have a material adverse effect on
     the Company.
 
          (d) The Company has not transported or arranged for the transportation
     of any Hazardous Material to any location which is the subject of any
     action, suit, arbitration or proceeding that could be reasonably expected
     to lead to claims against the Company for clean-up costs, remedial work,
     damages to natural resources or personal injury claims, which could be
     reasonably expected to have a material adverse impact on the Company
     including, but not limited to, claims under the Comprehensive Environmental
     Response, Compensation and Liability Act of 1980, as amended, and the rules
     and regulations promulgated thereunder ("CERCLA").
 
          (e) No oral or written notification of a Release of a Hazardous
     Material has been filed by or on behalf of the Company and no property now
     or previously owned or leased by the Company is listed or proposed for
     listing on the National Priorities List promulgated pursuant to CERCLA or
     on any similar state list of sites requiring investigation or clean-up.
 
          (f) There are no Liens arising under or pursuant to any Environmental
     Law with respect to any real property owned or leased by the Company, other
     than any such Liens against real property not individually or in the
     aggregate material to the Company, and no action of any Governmental or
     Regulatory Authority has been taken or is in process which could subject
     any of such properties to such Liens, and the Company would not be required
     to place any notice or restriction relating to the presence of Hazardous
     Material at any such property owned by it in any deed to such property.
 
          (g) There have been no environmental investigations, studies, audits,
     tests, reviews or other analyses conducted by, or which are in the
     possession of, the Company in relation to any property or facility now or
     previously owned or leased by the Company which have not been delivered to
     Harsco prior to the execution of this Agreement.
 
          (h) As used herein:
 
             (i) "Environmental Law" means any Law of any Governmental or
        Regulatory Authority relating to human health, safety or protection of
        the environment or to emissions, discharges, releases or threatened
        releases of pollutants, contaminants or Hazardous Materials in the
        environment (including, without limitation, ambient air, surface water,
        ground water, land surface or subsurface strata), or otherwise relating
        to the treatment, storage, disposal, transport or handling of any
        Hazardous Material; and
 
             (ii) "Hazardous Material" means (A) any petroleum or petroleum
        products, radioactive materials, asbestos in any form that is or could
        become friable, urea formaldehyde foam insulation and transformers or
        other equipment that contain dielectric fluid containing levels of
        regulated polychlorinated biphenyls (PCBs); (B) any chemicals,
        materials, substances or wastes which are now or hereafter become
        defined as or included in the definition of "hazardous substances,"
        "hazardous wastes," "hazardous materials," "extremely hazardous wastes,"
        "restricted hazardous wastes," "toxic substances," "toxic pollutants" or
        words of similar import, under any Environmental Law; and (C) any other
        chemical, material, substance or waste, exposure to which is now or
        hereafter prohibited, limited or regulated by any Governmental or
        Regulatory Authority.
 
     3.17 Tangible Property and Assets. Except as disclosed in Schedule 3.17
hereto, the Company has good and marketable title to, or has valid leasehold
interests in or valid rights under contract to use, all tangible property and
assets used in and, individually or in the aggregate, material to the conduct of
the businesses of the Company free and clear of all Liens other than (i) any
statutory Lien arising in the ordinary course of business by operation of law
with respect to a liability that is not yet due or delinquent and (ii) any minor
imperfection of title or similar Lien which individually or in the aggregate
with other such Liens does not materially impair the value of the property or
asset subject to such Lien or the use of such property or asset in the conduct
of the business of the Company. All such property and assets are, in all
material respects, in good working order and condition, ordinary wear and tear
excepted, and adequate and suitable for the purposes for which they are
presently being used.
 
                                      56
<PAGE>   18
 
     3.18 Intellectual Property Rights. The Company has all right, title and
interest in, or a valid and binding license to use, all Intellectual Property
(as defined below) individually or in the aggregate material to the conduct of
the businesses of the Company. The Company is not in default (or with the giving
of notice or lapse of time or both, would be in default) in any material respect
under any license to use such Intellectual Property, such Intellectual Property
is not being infringed by any third party, and the Company is not infringing any
Intellectual Property of any third party, except for such defaults and
infringements which, individually or in the aggregate, are not having and could
not be reasonably expected to have a material adverse effect on the Company. For
purposes of this Agreement, "Intellectual Property" means patents and patent
rights, trademarks and trademark rights, trade names and trade name rights,
service marks and service mark rights, service names and service name rights,
copyright and copyright rights and other proprietary intellectual property
rights and all pending applications for and registrations of any of the
foregoing.
 
     3.19 Vote Required. The affirmative vote of the holders of record of at
least two-thirds of the outstanding shares of Company Common Stock with respect
to the adoption of this Agreement is the only vote of the holders of any class
or series of the capital stock of the Company required to adopt this Agreement
and approve the Merger and the other transactions contemplated hereby and by the
Stock Option Agreement.
 
     3.20 Opinion of Financial Advisor. If McDonald & Company Securities
delivers to the Company an opinion, dated the date hereof, to the effect that,
as of the date hereof, the consideration to be received in the Merger by the
shareholders of the Company is fair from a financial point of view to the
shareholders of the Company, a true and complete copy of such opinion shall be
delivered to Harsco prior to the execution of this Agreement.
 
                                   ARTICLE IV
 
          REPRESENTATIONS AND WARRANTIES OF HARSCO AND ACQUISITION SUB
 
     Harsco and Acquisition Sub represent and warrant to the Company as follows:
 
     4.01 Organization and Qualification. Each of Harsco and Acquisition Sub is
a corporation duly organized, validly existing and in good standing under the
laws of its jurisdiction of incorporation. Acquisition Sub was formed solely for
the purpose of engaging in the transactions contemplated by this Agreement and
the Stock Option Agreement, has engaged in no other business activities and has
conducted its operations only as contemplated hereby. Each of Harsco and
Acquisition Sub is duly qualified, licensed or admitted to do business and is in
good standing in each jurisdiction in which the ownership, use or leasing of its
assets and properties, or the conduct or nature of its business, makes such
qualification, licensing or admission necessary, except for such failures to be
so qualified, licensed or admitted and in good standing which, individually or
in the aggregate, could not be reasonably expected to have a material adverse
effect on the validity or enforceability of this Agreement or the Stock Option
Agreement or on the ability of Harsco or Acquisition Sub to perform its
obligations hereunder or thereunder.
 
     4.02 Authority Relative to this Agreement and the Stock Option Agreement.
Each of Harsco and Acquisition Sub has full corporate power and authority to
enter into this Agreement and the Stock Option Agreement and to perform its
obligations hereunder and thereunder and to consummate the transactions
contemplated hereby and thereby. The execution, delivery and performance of this
Agreement and the Stock Option Agreement by each of Harsco and Acquisition Sub
and the consummation by each of Harsco and Acquisition Sub of the transactions
contemplated hereby and thereby have been duly and validly approved by their
respective Boards of Directors and by Harsco in its capacity as the sole
shareholder of Acquisition Sub and no other corporate proceedings on the part of
Harsco or Acquisition Sub or their shareholders are necessary to authorize the
execution, delivery and performance of this Agreement and the Stock Option
Agreement by Harsco or Acquisition Sub and the consummation by Harsco or
Acquisition Sub of the transactions contemplated hereby and thereby. This
Agreement and the Stock Option Agreement have been duly and validly executed and
delivered by Harsco and Acquisition Sub and constitute legal, valid and binding
obligation of Harsco and Acquisition Sub enforceable against Harsco and
Acquisition Sub in accordance with their terms, except as enforceability may be
limited by bankruptcy, insolvency, reorganization, moratorium or other similar
laws affecting the enforcement of creditors'
 
                                      57
<PAGE>   19
 
rights generally and by general equitable principles (regardless of whether such
enforceability is considered in a proceeding in equity or at law).
 
     4.03  Non-Contravention; Approvals and Consents.
 
          (a) The execution and delivery of this Agreement and the Stock Option
     Agreement by Harsco and Acquisition Sub do not, and the performance by
     Harsco and Acquisition Sub of their obligations hereunder and thereunder
     and the consummation of the transactions contemplated hereby and thereby
     will not, conflict with, result in a violation or breach of, constitute
     (with or without notice or lapse of time or both) a default under, result
     in or give to any person any right of termination, cancellation,
     modification or acceleration of, or result in the creation or imposition of
     any Lien upon any of the assets or properties of Harsco or any of its
     Subsidiaries under, any of the terms, conditions or provisions of (i) the
     certificates or articles of incorporation or bylaws (or other comparable
     charter documents) of Harsco or any of its Subsidiaries, or (ii) subject to
     the taking of the actions described in paragraph (b) of this Section, (x)
     any Law or Order of any Governmental or Regulatory Authority applicable to
     Harsco or any of its Subsidiaries or any of their respective assets or
     properties, or (y) any Contract to which Harsco or any of its Subsidiaries
     is a party or by which Harsco or any of its Subsidiaries or any of their
     respective assets or properties is bound, excluding from the foregoing
     clauses (x) and (y) conflicts, violations, breaches, defaults,
     terminations, modifications, accelerations and creations and impositions of
     Liens which, individually or in the aggregate, could not be reasonably
     expected to have a material adverse effect on the ability of Harsco and
     Acquisition Sub to consummate the transactions contemplated by this
     Agreement and the Stock Option Agreement.
 
          (b) Except (i) for the filing of a premerger notification report by
     Harsco under the HSR Act, (ii) for the filing of the Certificate of Merger,
     the Articles of Merger and other appropriate merger documents required by
     the OGCL and the PBCL with the Ohio Secretary of State and the Pennsylvania
     Secretary of State and appropriate documents with the relevant authorities
     of other states in which the Constituent Corporations are qualified to do
     business, and (iii) as disclosed in Schedule 4.03 hereto, no consent,
     approval or action of, filing with or notice to any Governmental or
     Regulatory Authority or other public or private third party is necessary or
     required under any of the terms, conditions or provisions of any Law or
     Order of any Governmental or Regulatory Authority or any Contract to which
     Harsco or any of its Subsidiaries is a party or by which Harsco or any of
     its Subsidiaries or any of their respective assets or properties is bound
     for the execution and delivery of this Agreement and the Stock Option
     Agreement by Harsco and Acquisition Sub, the performance by Harsco and
     Acquisition Sub of their obligations hereunder and thereunder or the
     consummation of the transactions contemplated hereby and thereby, other
     than such consents, approvals, actions, filings and notices which the
     failure to make or obtain, as the case may be, individually or in the
     aggregate, could not be reasonably expected to have a material adverse
     effect on the ability of Harsco and Acquisition Sub to consummate the
     transactions contemplated by this Agreement and the Stock Option Agreement.
 
     4.04 Legal Proceedings. There are no actions, suits, arbitrations or
proceedings pending or, to the knowledge of Harsco and its Subsidiaries,
threatened against, relating to or affecting, nor to the knowledge of Harsco and
its Subsidiaries are there any Governmental or Regulatory Authority
investigations or audits pending or threatened against, relating to or
affecting, Harsco or any of its Subsidiaries or any of their respective assets
and properties which, if determined adversely to Harsco or any of its
Subsidiaries, individually or in the aggregate, could be reasonably expected to
have a material adverse effect on the ability of Harsco and Acquisition Sub to
consummate the transactions contemplated by this Agreement. Neither Harsco nor
any of its Subsidiaries is subject to any Order of any Governmental or
Regulatory Authority which, individually or in the aggregate, could be
reasonably expected to have a material adverse effect on the ability of Harsco
and Acquisition Sub to consummate the transactions contemplated by this
Agreement or the Stock Option Agreement.
 
     4.05 Information Supplied. Neither the information supplied or to be
supplied in writing by or on behalf of Harsco or Acquisition Sub for inclusion,
nor the information incorporated by reference from documents filed by Harsco or
any of its Subsidiaries with the SEC, in the Proxy Statement or any other
documents to be filed by Harsco, Acquisition Sub or the Company with the SEC or
any other Governmental or Regulatory Authority in connection with the Merger and
the other transactions contemplated hereby or by the Stock Option Agreement
 
                                      58
<PAGE>   20
 
will on the date of its filing or, in the case of the Proxy Statement, at the
date it is mailed to shareholders, and at the time of the Company Shareholders'
Meeting, contain any untrue statement of a material fact or omit to state any
material fact required to be stated therein or necessary in order to make the
statements therein, in light of the circumstances under which they are made, not
misleading. All such documents filed by Harsco or Acquisition Sub with the SEC
under the Exchange Act will comply as to form in all material respects with the
requirements of the Exchange Act.
 
     4.06  Financing.  Harsco has sufficient cash and/or available credit
facilities to pay the aggregate Merger Price in accordance with this Agreement
and to make all other necessary payments of fees and expenses in connection with
the transactions contemplated by this Agreement and the Stock Option Agreement.
 
                                   ARTICLE V
 
                            COVENANTS OF THE COMPANY
 
     5.01  Conduct of Business.  At all times from and after the date hereof
until the Effective Time, the Company covenants and agrees that (except as
expressly contemplated or permitted by this Agreement or the Stock Option
Agreement, or to the extent that Harsco shall otherwise consent in writing,
which consent shall not be unreasonably withheld):
 
          (a)  Ordinary Course.  The Company shall conduct its business only in,
     and the Company shall not take any action except in, the ordinary course
     consistent with past practice.
 
          (b)  Without limiting the generality of paragraph (a) of this Section,
     (i) the Company shall use all commercially reasonable efforts to preserve
     intact in all material respects its present business organization and
     reputation, to keep available the services of its key officers and
     employees, to maintain its assets and properties in good working order and
     condition, ordinary wear and tear excepted, to maintain insurance on its
     tangible assets and businesses in such amounts and against such risks and
     losses as are currently in effect, to preserve its relationships with
     customers and suppliers and others having significant business dealings
     with them and to comply in all material respects with all Laws and Orders
     of all Governmental or Regulatory Authorities applicable to them, and (ii)
     the Company shall not:
 
             (A)  amend or propose to amend its articles of incorporation or
        regulations (or other comparable corporate charter documents);
 
             (B)  (w) declare, set aside or pay any dividends on or make other
        distributions in respect of any of its capital stock other than the
        regular cash dividend for the first quarter of 1998 in an amount
        consistent with past practice, and payable at a time prior to April 30,
        1998; provided, however, that in no event shall such first quarter
        regular cash dividend exceed $.09 per share; and provided further, that
        in no event shall such dividend be paid after April 30, 1998; (x) split,
        combine, reclassify or take similar action with respect to any of its
        capital stock or issue or authorize or propose the issuance of any other
        securities in respect of, in lieu of or in substitution for shares of
        its capital stock, (y) adopt a plan of complete or partial liquidation
        or resolutions providing for or authorizing such liquidation or a
        dissolution, merger, consolidation, restructuring, recapitalization or
        other reorganization or (z) directly or indirectly redeem, repurchase or
        otherwise acquire any shares of its capital stock or any Option with
        respect thereto;
 
             (C)  issue, deliver or sell, or authorize or propose the issuance,
        delivery or sale of, any shares of its capital stock or any Option with
        respect thereto, or modify or amend any right of any holder of
        outstanding shares of capital stock or Options with respect thereto;
 
             (D)  acquire (by merging or consolidating with, or by purchasing a
        substantial equity interest in or a substantial portion of the assets
        of, or by any other manner) any business or any corporation,
        partnership, association or other business organization or division
        thereof or otherwise acquire or agree to acquire any assets other than
        in the ordinary course of its business consistent with past practice;
 
                                      59
<PAGE>   21
 
             (E)  other than dispositions in the ordinary course of its business
        consistent with past practice, sell, lease, grant any security interest
        in or otherwise dispose of or encumber any of its assets or properties;
 
             (F)  except to the extent required by applicable law or GAAP, (x)
        permit any material change in (A) any pricing, marketing, purchasing,
        investment, accounting, financial reporting, inventory, credit,
        allowance or tax practice or policy or (B) any method of calculating any
        bad debt, contingency or other reserve for accounting, financial
        reporting or tax purposes or (y) make any material tax election or
        settle or compromise any material income tax liability with any
        Governmental or Regulatory Authority;
 
             (G)  (x) incur (which shall not be deemed to include entering into
        credit agreements, lines of credit or similar arrangements until
        borrowings are made under such arrangements) any indebtedness for
        borrowed money or guarantee any such indebtedness other than in the
        ordinary course of its business consistent with past practice, or (y)
        voluntarily purchase, cancel, prepay or otherwise provide for a complete
        or partial discharge in advance of a scheduled repayment date with
        respect to, or waive any right under, any indebtedness for borrowed
        money other than in the ordinary course of its business consistent with
        past practice;
 
             (H)  enter into, adopt, amend in any material respect (except as
        may be required by applicable law) or terminate any Company Benefit Plan
        or other agreement, arrangement, plan or policy between the Company and
        one or more of its directors, officers or employees, or, except for
        normal increases in the ordinary course of business consistent with past
        practice that, in the aggregate, do not result in a material increase in
        benefits or compensation expense to the Company, increase in any manner
        the compensation or fringe benefits of any director, officer or employee
        or pay any benefit not required by any plan or arrangement in effect as
        of the date hereof, except for normal increases in the ordinary course
        of business consistent with past practice that, in the aggregate, do not
        result in a material increase in benefits or compensation expense to the
        Company;
 
             (I)  enter into any contract or amend or modify any existing
        contract, or engage in any new transaction outside the ordinary course
        of business consistent with past practice or not on an arm's length
        basis, with any affiliate of the Company;
 
             (J)  make any capital expenditures or commitments for additions to
        plant, property or equipment constituting capital assets, except in the
        ordinary course of business consistent with past practice;
 
             (K)  make any change in the lines of business in which it
        participates or is engaged; or
 
             (L)  enter into any contract, agreement, commitment or arrangement
        to do or engage in any of the foregoing.
 
          (c)  Advice of Changes.  The Company shall confer on a regular and
     frequent basis with Harsco with respect to its business and operations and
     other matters relevant to the Merger, and shall promptly advise Harsco, in
     writing, of any change or event, including, without limitation, any
     complaint, investigation or hearing by any Governmental or Regulatory
     Authority (or communication indicating the same may be contemplated) or the
     institution or threat of litigation, having, or which, insofar as can be
     reasonably foreseen, could have, a material adverse effect on the Company
     or on the ability of the Company to consummate the transactions
     contemplated hereby.
 
     5.02  No Solicitations.  The Company shall not, and it shall not authorize
or permit any officer, director, employee, investment banker, financial advisor,
attorney, accountant or other agent or representative (each, a "Representative")
retained by or acting for or on behalf of the Company to, directly or
indirectly, initiate, solicit, encourage, or, unless the Board of Directors of
the Company believes, on the basis of written advice furnished by independent
legal counsel, that the failure to take such actions would constitute a breach
of applicable fiduciary duties, participate in any negotiations regarding,
furnish any confidential information in connection with, endorse or otherwise
cooperate with, assist, participate in or facilitate the making of any proposal
or offer for, or which may reasonably be expected to lead to, an Acquisition
Transaction (as defined below), by any person, corporation, partnership or other
entity or group (a "Potential Acquiror"). The Company shall promptly inform
 
                                      60
<PAGE>   22
 
Harsco, in writing, of the material terms and conditions of any proposal or
offer for, or which may reasonably be expected to lead to, an Acquisition
Transaction that it receives and the identity of the Potential Acquiror. The
Company will immediately cease and cause to be terminated any existing
activities, discussions or negotiations with any parties conducted heretofore
with respect to any Acquisition Transaction. As used in this Agreement,
"Acquisition Transaction" means any merger, consolidation or other business
combination involving the Company, or any acquisition in any manner of all or a
substantial portion of the equity of, or all or a substantial portion of the
assets of the Company whether for cash, securities or any other consideration or
combination thereof other than pursuant to the transactions contemplated by this
Agreement and the Stock Option Agreement.
 
                                   ARTICLE VI
 
                             ADDITIONAL AGREEMENTS
 
     6.01  Access to Information; Confidentiality.
 
          (a)  The Company shall, throughout the period from the date hereof to
     the Effective Time, (i) provide Harsco and its Representatives with full
     access, upon reasonable prior notice and during normal business hours, to
     all officers, employees, agents and accountants of the Company and its
     assets, properties, books and records, and (ii) furnish promptly to such
     persons (x) a copy of each report, statement, schedule and other document
     filed or received by the Company pursuant to the requirements of federal or
     state securities laws or filed with any other Governmental or Regulatory
     Authority, and (y) all other information and data (including, without
     limitation, copies of Contracts, Company Benefit Plans and other books and
     records) concerning the business and operations of the Company as Harsco or
     any of such other persons reasonably may request. No investigation pursuant
     to this paragraph or otherwise shall affect any representation or warranty
     contained in this Agreement or any condition to the obligations of the
     parties hereto.
 
          (b)  Harsco will hold, and will use its best efforts to cause its
     Representatives to hold, in strict confidence, unless (i) compelled to
     disclose by judicial or administrative process or by other requirements of
     applicable Laws of Governmental or Regulatory Authorities (including,
     without limitation, in connection with obtaining the necessary approvals of
     this Agreement or the transactions contemplated hereby of Governmental or
     Regulatory Authorities), or (ii) disclosed in an action or proceeding
     brought by a party hereto in pursuit of its rights or in the exercise of
     its remedies hereunder, all documents and information concerning the
     Company furnished to it by the Company or its Representatives in connection
     with this Agreement or the transactions contemplated hereby, except to the
     extent that such documents or information can be shown to have been (x)
     previously known by Harsco or its Representatives, (y) in the public domain
     (either prior to or after the furnishing of such documents or information
     hereunder) through no fault of Harsco and its Representatives or (z) later
     acquired by Harsco or its Representatives from another source if Harsco or
     such Representative is not aware that such source is under an obligation to
     the Company to keep such documents and information confidential. In the
     event that this Agreement is terminated without the transactions
     contemplated hereby having been consummated, upon the request of the
     Company, Harsco will, and will cause its Representatives to, promptly
     redeliver or cause to be redelivered all copies of documents and
     information furnished by the Company or its Representatives to Harsco and
     its Representatives in connection with this Agreement or the transactions
     contemplated hereby and destroy or cause to be destroyed all notes,
     memoranda, summaries, analyses, compilations and other writings related
     thereto or based thereon prepared by Harsco or its Representatives.
 
     6.02  Preparation of Proxy Statement.  The Company shall prepare and file
with the SEC the Proxy Statement as soon as reasonably practicable after the
date hereof, and shall use its best efforts to have the Proxy Statement cleared
by the SEC. If at any time prior to the Effective Time any event shall occur
that should be set forth in an amendment of or a supplement to the Proxy
Statement, the Company shall prepare and file with the SEC such amendment or
supplement as soon thereafter as is reasonably practicable. Harsco, Acquisition
Sub and the Company shall cooperate with each other in the preparation of the
Proxy Statement, and the Company shall notify Harsco of the receipt of any
comments of the SEC with respect to the Proxy Statement and of any requests by
the SEC for any amendment or supplement thereto or for additional information,
and shall provide to Harsco promptly copies of all correspondence between the
Company or any representative of the Company and the SEC
 
                                      61
<PAGE>   23
 
with respect to the Proxy Statement. The Company shall give Harsco and its
counsel the opportunity to review the Proxy Statement and all responses to
requests for additional information by and replies to comments of the SEC before
their being filed with, or sent to, the SEC. Each of the Company, Harsco and
Acquisition Sub agrees to use its best efforts, after consultation with the
other parties hereto, to respond promptly to all such comments of and requests
by the SEC and to cause the Proxy Statement to be mailed to the holders of
Company Common Stock entitled to vote at the Company Shareholders' Meeting at
the earliest practicable time.
 
     6.03  Approval of Shareholders.  The Company shall, through its Board of
Directors, duly call, give notice of, convene and hold a meeting of its
shareholders (the "Company Shareholders' Meeting") for the purpose of voting on
the adoption of this Agreement (the "Company Shareholders' Approval") as soon as
reasonably practicable after the date hereof. Except to the extent legally
required for the discharge of its fiduciary duties as reflected in a written
opinion of counsel, the Company shall, through its Board of Directors, include
in the Proxy Statement the recommendation of the Board of Directors of the
Company that the shareholders of the Company adopt this Agreement, and shall use
its best efforts to obtain such adoption. At such meeting, Harsco shall, and
shall cause its Subsidiaries to, cause all shares of Company Common Stock then
owned by Harsco or any such Subsidiary to be voted in favor of the adoption of
this Agreement.
 
     6.04  Regulatory and Other Approvals.  Subject to the terms and conditions
of this Agreement and without limiting the provisions of Sections 6.02 and 6.03,
each of the Company and Harsco will proceed diligently and in good faith and
will use all commercially reasonable efforts to do, or cause to be done, all
things necessary, proper or advisable to, as promptly as practicable, (a) obtain
all consents, approvals or actions of, make all filings with and give all
notices to Governmental or Regulatory Authorities or any other public or private
third parties required of Harsco, the Company or any of their Subsidiaries to
consummate the Merger and the other matters contemplated hereby and by the Stock
Option Agreement, and (b) provide such other information and communications to
such Governmental or Regulatory Authorities or other public or private third
parties as the other party or such Governmental or Regulatory Authorities or
other public or private third parties may reasonably request. In addition to and
not in limitation of the foregoing, (i) each of the parties will (x) take
promptly all actions necessary to make the filings required of Harsco and the
Company or their affiliates under the HSR Act, (y) comply at the earliest
practicable date with any request for additional information received by such
party or its affiliates from the Federal Trade Commission (the "FTC") or the
Antitrust Division of the Department of Justice (the "Antitrust Division")
pursuant to the HSR Act, and (z) cooperate with the other party in connection
with such party's filings under the HSR Act and in connection with resolving any
investigation or other inquiry concerning the Merger or the other matters
contemplated by this Agreement commenced by either the FTC or the Antitrust
Division or state attorneys general
 
     6.05  Benefit Plans.
 
          (a)  Company Employees Not Subject to Collective Bargaining Agreements
     ("Non-Unionized Employees"):
 
             (i)  Harsco shall have the right (but not the obligation) to
        employ, as officers and employees of Harsco or the Surviving
        Corporation, any persons who are officers and Non-Unionized Employees of
        the Company immediately before the Effective Time. It shall be a
        condition to employment by Harsco or the Surviving Corporation that any
        former officer or Non-Unionized Employee of the Company agree to cancel
        any existing employment contract, agreement or understanding between him
        or herself and the Company, including without limitation, all benefits
        related to severance arrangements upon a change of control or otherwise,
        prior to accepting such new employment and without accepting any of the
        severance benefits or other benefits or payments associated with such
        contract, agreement or understanding.
 
             (ii)  Each Non-Unionized Employee employed by the Company prior to
        the Effective Time who remains an employee of the Surviving Corporation
        or Harsco, following the Effective Time (each a "Continued Employee")
        shall be entitled, as an employee of Harsco or the Surviving
        Corporation, to participate in whatever employee benefit plans, as
        defined in Section 3(3) of ERISA, or whatever stock option, bonus or
        incentive plans or other fringe benefit programs that may be in effect
        generally for employees of Harsco or its Subsidiaries from time to time
        ("Harsco's Plans"), if such Continued
 
                                      62
<PAGE>   24
 
        Employee shall be eligible or selected for participation therein and
        otherwise shall not be participating in a similar plan which continues
        to be maintained by the Surviving Corporation for such employee. All
        such participation shall be subject to such terms of such plans as may
        be in effect from time to time provided, further that Continued
        Employees will be eligible to participate in Harsco's Plans on the same
        basis as similarly situated employees of Harsco or its Subsidiaries.
        Such Continued Employees will receive credit for past service with the
        Company for purposes of eligibility and vesting, but not benefit
        accrual, under Harsco's Plans.
 
             (iii)  the Company shall take all timely and necessary action to
        cease participation or accrual of benefits, effective as of the
        Effective Time, by each Non-Unionized Employee employed by the Company
        prior to the Effective Time in each Company Benefit Plan, and to
        terminate each Company Benefit Plan, effective as of the Effective Time;
        provided that Harsco may, in its sole discretion, give notice to the
        Company, not less than 20 days (61 days in the case of any pension plan)
        prior to the Effective Time, that any Company Benefit Plan shall not be
        terminated and/or participation or accrual of benefits thereunder shall
        not cease pursuant to this Section 6.05. At the sole discretion of
        Harsco, the assets of any Company Benefit Plan may be transferred to any
        similar such plan maintained and designated by Harsco, effective at or
        after the Effective Time, as elected by Harsco, and if Harsco so elects,
        the Company shall take any and all timely and necessary action to effect
        such transfer.
 
          (b)  Company Employees Subject to Collective Bargaining Agreements
     ("Unionized Employees"):
 
             (i)  the rights, duties and obligations of the Company's Unionized
        Employees after the Effective Time shall be governed and controlled by
        such employees' respective collective bargaining agreements with the
        Company as in effect at the Effective Time.
 
     6.06  Stock Option Agreement.  The Company, Harsco and Acquisition Sub
shall perform fully their respective obligations under the Stock Option
Agreement.
 
     6.07  Expenses.  Except as set forth in Section 8.02, whether or not the
Merger is consummated, all costs and expenses incurred in connection with this
Agreement and the Stock Option Agreement and the transactions contemplated
hereby and thereby shall be paid by the party incurring such cost or expense.
 
     6.08  Brokers or Finders.  Each of Harsco and the Company represents, as to
itself and its affiliates, that no agent, broker, investment banker, financial
advisor or other firm or person is or will be entitled to any broker's or
finder's fee or any other commission or similar fee in connection with any of
the transactions contemplated by this Agreement except McDonald & Company
Securities, Inc. whose fees and expenses will be paid by the Company in
accordance with the Company's agreement with such firm (a true and complete copy
of which has been delivered by the Company to Harsco prior to the execution of
this Agreement), and each of Harsco and the Company shall indemnify and hold the
other harmless from and against any and all claims, liabilities or obligations
with respect to any other such fee or commission or expenses related thereto
asserted by any person on the basis of any act or statement alleged to have been
made by such party or its affiliate.
 
     6.09  Notice and Cure.  Each of Harsco and the Company will notify the
other promptly in writing of, and contemporaneously will provide the other with
true and complete copies of any and all information or documents relating to,
and will use all commercially reasonable efforts to cure before the Closing, any
event, transaction or circumstance occurring after the date of this Agreement
that causes or will cause any covenant or agreement of Harsco or the Company, as
the case may be, under this Agreement to be breached or that renders or will
render untrue any representation or warranty of Harsco or the Company, as the
case may be, contained in this Agreement as if the same were made on or as of
the date of such event, transaction or circumstance. Each of Harsco and the
Company also will notify the other promptly in writing of, and will use all
commercially reasonable efforts to cure, before the Closing, any violation or
breach of any representation, warranty, covenant or agreement made by Harsco or
the Company, as the case may be, in this Agreement, whether occurring or arising
prior to, on or after the date of this Agreement. No notice given pursuant to
this Section shall have any effect on the representations, warranties, covenants
or agreements contained in this Agreement for purposes of determining
satisfaction of any condition contained herein.
 
                                      63
<PAGE>   25
 
     6.10  Fulfillment of Conditions.  Subject to the terms and conditions of
this Agreement, each of Harsco and the Company will take or cause to be taken
all commercially reasonable steps necessary or desirable and proceed diligently
and in good faith to satisfy each condition to the other's obligations contained
in this Agreement and to consummate and make effective the transactions
contemplated by this Agreement, and neither Harsco nor the Company will, nor
will it permit any of its Subsidiaries to, take or fail to take any action that
could be reasonably expected to result in the nonfulfillment of any such
condition.
 
     6.11  1997 Audited Financial Statements.  The Company shall cause to be
delivered to Harsco the audited financial statements of the Company for the year
ended December 31, 1997 as soon as the same are available, but in no event later
than 5 days prior to Closing.
 
                                  ARTICLE VII
 
                                   CONDITIONS
 
     7.01  Conditions to Each Party's Obligation to Effect the Merger.  The
respective obligation of each party to effect the Merger is subject to the
fulfillment, at or prior to the Closing, of each of the following conditions:
 
          (a)  Shareholder Approval.  This Agreement shall have been adopted by
     the requisite vote of the shareholders of the Company under the OGCL and
     the Company's Articles of Incorporation.
 
          (b)  HSR Act.  Any waiting period (and any extension thereof)
     applicable to the consummation of the Merger under the HSR Act shall have
     expired or been terminated.
 
          (c)  No Injunctions or Restraints.  No court of competent jurisdiction
     or other competent Governmental or Regulatory Authority shall have enacted,
     issued, promulgated, enforced or entered any Law or Order (whether
     temporary, preliminary or permanent) which is then in effect and has the
     effect of making illegal or otherwise restricting, preventing or
     prohibiting consummation of the Merger or the other transactions
     contemplated by this Agreement and the Stock Option Agreement.
 
          (d)  Governmental and Regulatory Consents and Approvals.  Other than
     the filing provided for by Section 1.02, all consents, approvals and
     actions of, filings with and notices to any Governmental or Regulatory
     Authority or any other public or private third party required of Harsco,
     the Company or any of their Subsidiaries to consummate the Merger and the
     other matters contemplated hereby and by the Stock Option Agreement, the
     failure of which to be obtained or taken could be reasonably expected to
     have a material adverse effect on Harsco and its Subsidiaries or the
     Surviving Corporation and its Subsidiaries, in each case taken as a whole,
     or on the ability of Harsco and the Company to consummate the transactions
     contemplated hereby or by the Stock Option Agreement shall have been
     obtained, all in form and substance reasonably satisfactory to Harsco and
     no such consent, approval or action shall contain any term or condition
     which could be reasonably expected to result in a material diminution of
     the benefits of the Merger to Harsco.
 
     7.02  Conditions to Obligation of Harsco and Acquisition Sub to Effect the
Merger.  The obligation of Harsco and Acquisition Sub to effect the Merger is
further subject to the fulfillment, at or prior to the Closing, of each of the
following additional conditions (all or any of which may be waived in whole or
in part by Harsco and Acquisition Sub in their sole discretion):
 
          (a)  Representations and Warranties.  Each of the representations and
     warranties made by the Company in this Agreement shall be true and correct
     in all material respects as of the Closing Date as though made on and as of
     the Closing Date or, in the case of representations and warranties made as
     of a specified date earlier than the Closing Date, on and as of such
     earlier date and the Company shall have delivered to Harsco a certificate,
     dated the Closing Date and executed on behalf of the Company by its
     Chairman of the Board, President or any Vice President, to such effect.
 
          (b)  Performance of Obligations.  The Company shall have performed and
     complied with, in all material respects, each agreement, covenant and
     obligation required by this Agreement to be so performed or complied with
     by the Company at or prior to the Closing, and the Company shall have
     delivered to Harsco
 
                                      64
<PAGE>   26
 
     a certificate, dated the Closing Date and executed on behalf of the Company
     by its Chairman of the Board, President or any Vice President, to such
     effect.
 
          (c)  Orders and Laws.  There shall not have been issued, enacted,
     promulgated or deemed applicable to Harsco, the Surviving Corporation, any
     of their respective Subsidiaries or the transactions contemplated by this
     Agreement any Order or Law of any Governmental or Regulatory Authority
     which is then in effect and which could be reasonably expected to result in
     a material diminution of the benefits of the Merger to Harsco, and there
     shall not be pending or threatened on the Closing Date any action, suit or
     proceeding in, before or by any Governmental or Regulatory Authority which
     could be reasonably expected to result in any such issuance, enactment,
     promulgation or deemed applicability of any such Order or Law or of any
     Order or Law referred to in Section 7.01(c).
 
          (d)  Governmental and Regulatory Consents and Approvals.  Other than
     the filing provided for by Section 1.02, all consents, approvals and
     actions of, filings with and notices to any Governmental or Regulatory
     Authority, the failure of which to be obtained or taken could be reasonably
     expected to have a material adverse effect on Harsco and its Subsidiaries
     or the Surviving Corporation and its Subsidiaries, in each case taken as a
     whole, or on the ability of Harsco and the Company to consummate the
     transactions contemplated hereby or by the Stock Option Agreement shall
     have been obtained, all in form and substance reasonably satisfactory to
     Harsco and no such consent, approval or action shall contain any term or
     condition which could be reasonably expected to result in a material
     diminution of the benefits of the Merger to Harsco.
 
          (e)  Contractual Consents.  The Company shall have received, all in
     form and substance reasonably satisfactory to Harsco, all material consents
     (or in lieu thereof waivers) from parties to each Contract disclosed or
     which should have been disclosed pursuant to Section 3.04(b), and no such
     consent or waiver shall contain any term or condition which could be
     reasonably expected to result in a material diminution of the benefits of
     the Merger to Harsco.
 
          (f)  Opinion of Counsel.  Harsco and Acquisition Sub shall have
     received the opinion of Squire, Sanders & Dempsey LLP, counsel to the
     Company, dated the Closing Date, substantially in the form and to the
     effect of Exhibit A hereto.
 
          (g)  Proceedings.  All proceedings to be taken on the part of the
     Company in connection with the transactions contemplated by this Agreement
     and all documents incident thereto shall be reasonably satisfactory in form
     and substance to Harsco, and Harsco shall have received copies of all such
     documents and other evidences as Harsco may reasonably request in order to
     establish the consummation of such transactions and the taking of all
     proceedings in connection therewith.
 
          (h)  Dissenting Shares.  No more than seven percent (7%) of the
     outstanding Company Common Stock shall be Dissenting Shares.
 
     7.03  Conditions to Obligation of the Company to Effect the Merger.  The
obligation of the Company to effect the Merger is further subject to the
fulfillment, at or prior to the Closing, of each of the following additional
conditions (all or any of which may be waived in whole or in part by the Company
in its sole discretion):
 
          (a) Representations and Warranties. Each of the representations and
     warranties made by Harsco and Acquisition Sub in this Agreement shall be
     true and correct in all material respects as of the Closing Date as though
     made on and as of the Closing Date or, in the case of representations and
     warranties made as of a specified date earlier than the Closing Date, on
     and as of such earlier date, and Harsco and Acquisition Sub shall each have
     delivered to the Company a certificate, dated the Closing Date and executed
     on behalf of Harsco by its Chairman of the Board, President or any Vice
     President and on behalf of Acquisition Sub by its Chairman of the Board,
     President or any Vice President, to such effect.
 
          (b) Performance of Obligations. Harsco and Acquisition Sub shall have
     performed and complied with, in all material respects, each agreement,
     covenant and obligation required by this Agreement to be so performed or
     complied with by Harsco or Acquisition Sub at or prior to the Closing, and
     Harsco and Acquisition Sub shall each have delivered to the Company a
     certificate, dated the Closing Date and executed
 
                                      65
<PAGE>   27
 
     on behalf of Harsco by its Chairman of the Board, President or any Vice
     President and on behalf of Acquisition Sub by its Chairman of the Board,
     President or any Vice President, to such effect.
 
          (c) Opinion of Counsel. The Company shall have received the opinion of
     Morgan, Lewis & Bockius LLP, counsel to Harsco and Acquisition Sub, dated
     the Closing Date, substantially in the form and to the effect of Exhibit B
     hereto.
 
          (d) Proceedings. All proceedings to be taken on the part of Harsco and
     Acquisition Sub in connection with the transactions contemplated by this
     Agreement and all documents incident thereto shall be reasonably
     satisfactory in form and substance to the Company, and the Company shall
     have received copies of all such documents and other evidences as the
     Company may reasonably request in order to establish the consummation of
     such transactions and the taking of all proceedings in connection
     therewith.
 
                                  ARTICLE VIII
 
                       TERMINATION, AMENDMENT AND WAIVER
 
     8.01 Termination. This Agreement may be terminated, and the transactions
contemplated hereby may be abandoned, at any time prior to the Effective Time,
whether prior to or after the Company Shareholders' Approval:
 
          (a) by mutual written agreement of the parties hereto duly authorized
     by action taken by or on behalf of their respective Boards of Directors;
 
          (b) by either the Company or Harsco upon notification to the
     non-terminating party by the terminating party:
 
             (i) at any time after April 30, 1998 if the Merger shall not have
        been consummated on or prior to such date and such failure to consummate
        the Merger is not caused by a breach of this Agreement by the
        terminating party; provided however, the date may be extended
        indefinitely by the mutual written agreement of the parties; and
        provided further, that such date shall be extended by the parties for a
        reasonable period if the only condition hereunder that remains
        unsatisfied as of such date relates to the receipt of any Governmental
        or Regulatory Authority Consent or approval required in connection with
        this transaction including, without limitation, any consent or approval
        required under the HSR Act;
 
             (ii) if the Company Shareholders' Approval shall not be obtained by
        reason of the failure to obtain the requisite vote upon a vote held at a
        meeting of such shareholders, or any adjournment thereof, called
        therefor;
 
             (iii) if any Governmental or Regulatory Authority, the taking of
        action by which is a condition to the obligations of either the Company
        or Harsco to consummate the transactions contemplated hereby, shall have
        determined not to take such action and all appeals of such determination
        shall have been taken and have been unsuccessful;
 
             (iv) if there has been a material breach of any representation,
        warranty, covenant or agreement on the part of the non-terminating party
        set forth in this Agreement which breach has not been cured within 5
        business days following receipt by the non-terminating party of notice
        of such breach from the terminating party or assurance of such cure
        reasonably satisfactory to the terminating party shall not have been
        given by or on behalf of the non-terminating party within such 5
        business day period; or
 
             (v) if any court of competent jurisdiction or other competent
        Governmental or Regulatory Authority shall have issued an Order making
        illegal or otherwise restricting, preventing or prohibiting the Merger
        and such Order shall have become final and nonappealable.
 
     8.02 Effect of Termination. (a) If this Agreement is validly terminated by
either the Company or Harsco pursuant to Section 8.01, this Agreement will
forthwith become null and void and there will be no liability or obligation on
the part of either the Company or Harsco (or any of their respective
Representatives or affiliates), except (i) that the provisions of Sections
6.01(b), 6.06, 6.07, and 6.08 will continue to apply following any such
 
                                      66
<PAGE>   28
 
termination, and (ii) that nothing contained herein shall relieve any party
hereto from liability for wilful breach of its representations, warranties,
covenants or agreements contained in this Agreement and (iii) as provided in
paragraph (b) below.
 
          (b) In the event that (i) Harsco terminates this Agreement pursuant to
     Section 8.01(b)(iv), or (ii) either Harsco or the Company terminates this
     Agreement pursuant to Section 8.01(b)(ii) following a failure of the
     shareholders of the Company to approve this Agreement and, before the
     Company Shareholders' Meeting the Board of Directors of the Company shall
     have recommended that its shareholders accept any tender or exchange offer
     with respect to their Company Common Stock (other than an offer made by or
     on behalf of Harsco) or shall have withdrawn or modified in any manner
     adverse to Harsco its recommendation with respect to the Merger, then the
     Company shall, within one business day after receipt of a request from
     Harsco, pay to Harsco in cash a termination fee of $1.7 million.
 
     8.03 Amendment. This Agreement may be amended, supplemented or modified by
action taken by or on behalf of the respective Boards of Directors of the
parties hereto at any time prior to the Effective Time, whether prior to or
after adoption of this Agreement at the Company Shareholders' Meeting, but after
such adoption only to the extent permitted by applicable law. No such amendment,
supplement or modification shall be effective unless set forth in a written
instrument duly executed by or on behalf of each party hereto.
 
     8.04 Waiver. At any time prior to the Effective Time any party hereto, by
action taken by or on behalf of its Board of Directors, may to the extent
permitted by applicable law (i) extend the time for the performance of any of
the obligations or other acts of the other parties hereto, (ii) waive any
inaccuracies in the representations and warranties of the other parties hereto
contained herein or in any document delivered pursuant hereto or (iii) waive
compliance with any of the covenants, agreements or conditions of the other
parties hereto contained herein. No such extension or waiver shall be effective
unless set forth in a written instrument duly executed by or on behalf of the
party extending the time of performance or waiving any such inaccuracy or
non-compliance. No waiver by any party of any term or condition of this
Agreement, in any one or more instances, shall be deemed to be or construed as a
waiver of the same or any other term or condition of this Agreement on any
future occasion.
 
                                   ARTICLE IX
 
                               GENERAL PROVISIONS
 
     9.01 Non-Survival of Representations, Warranties, Covenants and Agreements.
The representations, warranties, covenants and agreements contained in this
Agreement or in any instrument delivered pursuant to this Agreement shall not
survive the Merger but shall terminate at the Effective Time.
 
     9.02 Knowledge. With respect to any representations or warranties contained
herein which are made to the knowledge of the Company or Harsco or any of their
respective Subsidiaries, as the case may be, the knowledge of the officers,
directors and employees of the Company or Harsco, as the case may be, and of the
officers, directors and employees of its respective Subsidiaries, shall be
imputed to the Company or Harsco, as the case may be, and such Subsidiaries.
 
     9.03 Notices. All notices, requests and other communications hereunder must
be in writing and will be deemed to have been duly given only if delivered
personally or by facsimile transmission or mailed (first class postage prepaid)
to the parties at the following addresses or facsimile numbers:
 
     If to Harsco or Acquisition Sub, to:
          Harsco Corporation
          350 Poplar Church Road
          P.O. Box 8888
          Camp Hill, PA 17001-8888
          Facsimile No.: (717) 763-6426
          Attn: General Counsel
 
                                      67
<PAGE>   29
 
     with a copy to:
 
          Morgan, Lewis & Bockius LLP
          One Commerce Square
          417 Walnut Street
          Harrisburg, PA 17101
          Facsimile No.: (717) 237-4013
          Attn: Charles L. O'Brien, Esquire
 
     If to the Company, to:
 
          Chemi-Trol Chemical Co.
          2776 County Road 69
          Gibsonburg, OH 43431
          Facsimile No.: (419) 334-5285
          Attn: Robert W. Woolf, Chairman, President and CEO
 
     with a copy to:
 
          Squire, Sanders & Dempsey LLP
          4900 Key Tower
          127 Public Square
          Cleveland, OH 44114-1304
          Facsimile No.: (216) 479-8780
          Attn: David A. Zagore, Esquire
 
All such notices, requests and other communications will (i) if delivered
personally to the address as provided in this Section, be deemed given upon
delivery, (ii) if delivered by facsimile transmission to the facsimile number as
provided in this Section, be deemed given upon receipt, and (iii) if delivered
by mail in the manner described above to the address as provided in this
Section, be deemed given upon receipt (in each case regardless of whether such
notice, request or other communication is received by any other person to whom a
copy of such notice is to be delivered pursuant to this Section). Any party from
time to time may change its address, facsimile number or other information for
the purpose of notices to that party by giving notice specifying such change to
the other parties hereto.
 
     9.04 Entire Agreement. Except for the Confidentiality Agreement executed by
and between Harsco and the Company, dated October 28, 1997, which shall remain
in full force and effect as provided therein, this Agreement and the Stock
Option Agreement supersede all prior discussions and agreements among the
parties hereto with respect to the subject matter hereof and thereof, including,
without limitation, that certain letter of intent between the Company and Harsco
dated December 8, 1997, and contain the sole and entire agreement among the
parties hereto with respect to the subject matter hereof and thereof.
Notwithstanding anything herein to the contrary, Harsco shall have the right to
exercise its rights and option under the Stock Option Agreement.
 
     9.05 Public Announcements. Except as otherwise required by law or the rules
of any applicable securities exchange or national market system, so long as this
Agreement is in effect, Harsco and the Company will not, and will not permit any
of their respective Representatives to, issue or cause the publication of any
press release or make any other public announcement with respect to the
transactions contemplated by this Agreement without the consent of the other
party, which consent shall not be unreasonably withheld. Harsco and the Company
will cooperate with each other in the development and distribution of all press
releases and other public announcements with respect to this Agreement and the
transactions contemplated hereby, and will furnish the other with drafts of any
such releases and announcements as far in advance as practicable.
 
     9.06 No Third Party Beneficiary. The terms and provisions of this Agreement
are intended solely for the benefit of each party hereto and their respective
successors or permitted assigns, and except as provided in Section 6.06, it is
not the intention of the parties to confer third-party beneficiary rights upon
any other person.
 
     9.07 No Assignment; Binding Effect. Neither this Agreement nor any right,
interest or obligation hereunder may be assigned by any party hereto without the
prior written consent of the other parties hereto and any attempt to do so will
be void, except that Acquisition Sub may assign any or all of its rights,
interests and obligations
 
                                      68
<PAGE>   30
 
hereunder to another direct or indirect wholly-owned Subsidiary of Harsco,
provided that any such Subsidiary agrees in writing to be bound by all of the
terms, conditions and provisions contained herein. subject to the preceding
sentence, this Agreement is binding upon, inures to the benefit of and is
enforceable by the parties hereto and their respective successors and assigns.
 
     9.08 Headings.The headings used in this Agreement have been inserted for
convenience of reference only and do not define or limit the provisions hereof.
 
     9.09 Invalid Provisions. If any provision of this Agreement is held to be
illegal, invalid or unenforceable under any present or future law, and if the
rights or obligations of any party hereto under this Agreement will not be
materially and adversely affected thereby, (i) such provision will be fully
severable, (ii) this Agreement will be construed and enforced as if such
illegal, invalid or unenforceable provision had never comprised a part hereof,
(iii) the remaining provisions of this Agreement will remain in full force and
effect and will not be affected by the legal, invalid or unenforceable provision
or by its severance herefrom and (iv) in lieu of such illegal, invalid or
unenforceable provision, there will be added automatically as a part of this
Agreement a legal, valid and enforceable provision as similar in terms to such
illegal, invalid or unenforceable provision as may be possible.
 
     9.10 Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the Commonwealth of Pennsylvania applicable to a
contract executed and performed in such State without giving effect to the
conflicts of laws principles thereof.
 
     9.11 Counterparts. This Agreement may be executed in any number of
counterparts, each of which will be deemed an original, but all of which
together will constitute one and the same instrument.
 
                                      69
<PAGE>   31
 
     IN WITNESS WHEREOF, each party hereto has caused this Agreement to be
signed by its officer thereunto duly authorized as of the date first above
written.
 
<TABLE>
<S>                                                    <C>
Attest:                                                HARSCO CORPORATION
 
/s/ Paul C. Coppock                                    By: /s/ Barry M. Sullivan
-----------------------------------------------------
          Secretary                                    -----------------------------------------------------
                                                           Name: Barry M. Sullivan
                                                           Title: Vice President -- Corporate Development
                                                                  and Treasurer
 
Attest:                                                H-CHEMI ACQUISITION CORP.
 
/s/ Paul C. Coppock                                    By: /s/ Barry M. Sullivan
-----------------------------------------------------
          Secretary                                    -----------------------------------------------------
                                                           Name: Barry M. Sullivan
                                                           Title: Treasurer
 
Attest:                                                CHEMI-TROL CHEMICAL CO.
 
/s/ Kevin D. Lauck                                     By: /s/ Robert W. Woolf
-----------------------------------------------------
          Secretary                                    -----------------------------------------------------
                                                           Name: Robert W. Woolf
                                                           Title: Chairman, President and CEO
</TABLE>
 
                                      70
<PAGE>   32
 
                                                                       EXHIBIT A
 
                      [OPINION OF COUNSEL TO THE COMPANY]
 
               , 1998
 
Harsco Corporation
350 Poplar Church Road
P. O. Box 8888
Camp Hill, PA 17001-8888
 
H-Chemi Acquisition Corp.
350 Poplar Church Road
P. O. Box 8888
Camp Hill, PA 17001-8888
 
Dear Sirs:
 
     We have acted as [special] counsel to Chemi-Trol Chemical Co., an Ohio
corporation (the "Company"), in connection with the Agreement and Plan of Merger
dated as of February   , 1998, (the "Merger Agreement"), by and among Harsco
corporation, a Delaware corporation, H-Chemi Acquisition Corp., a Pennsylvania
corporation, and the Company and the transactions contemplated thereby.
Capitalized terms not defined herein shall have the meanings ascribed to them in
the Merger Agreement. We are rendering this opinion to you pursuant to Section
7.02(f) of the Merger Agreement.
 
     In rendering the opinions expressed below, we have examined such documents
and such corporate records of the Company as we have deemed necessary as a basis
for the opinions hereinafter expressed. In such examination, we have assumed the
genuineness of all signatures, the authenticity of documents submitted to us as
originals, the conformity with the original documents of all documents submitted
to us as copies and the authenticity of the originals of such latter documents.
When facts relevant to such opinions were not independently established, we have
relied upon the representations and warranties as to factual matters made in or
pursuant to the Merger Agreement and upon certificates of government officials
and of the Company and its officers.
 
     Based upon the foregoing and having regard to legal considerations we deem
relevant, we are of the opinion that:
 
          1.  The Company is a corporation duly incorporated, validly existing
     and in good standing under the laws of its jurisdiction of incorporation
     and has full corporate power and authority to conduct its business as and
     to the extent now conducted and to own, use and lease its assets and
     properties.
 
          2.  The authorized capital stock of the Company consists solely of
     shares of Company Common Stock. As of             ,      ,           shares
     of Company Common Stock were issued and outstanding,           shares were
     held in the treasury of the Company. To our knowledge there has been no
     change in the number of issued and outstanding shares of Company Common
     Stock or shares of Company Common Stock held in treasury or reserved for
     issuance since such date other than the reservation of           shares
     pursuant to the Stock Option Agreement. All of the issued and outstanding
     shares of Company Common Stock are, and all shares reserved for issuance
     will be, upon issuance in accordance with the terms specified in the
     instruments or agreements pursuant to which they are issuable, duly
     authorized, validly issued, fully paid and nonassessable. To our knowledge,
     except pursuant to the Merger Agreement and the Stock Option Agreement and
     except as set forth in Schedule 3.02 to the Merger Agreement, there are no
     outstanding Options obligating the Company to issue or sell any shares of
     capital stock of the Company or to grant, extend or enter into any Option
     with respect thereto.



                                      71
<PAGE>   33
 
          3.  The Company has full corporate power and authority to enter into
     the Merger Agreement and the Stock Option Agreement, to perform its
     obligations thereunder and to consummate the transactions contemplated
     thereby. The execution, delivery and performance of the Merger Agreement
     and the Stock Option Agreement by the Company and the consummation by the
     Company of the transactions contemplated thereby have been duly and validly
     approved by the Board of Directors of the Company and the shareholders of
     the Company and no other corporate proceedings on the part of the Company
     or its shareholders are necessary to authorize the execution, delivery and
     performance of the Merger Agreement and the Stock Option Agreement by the
     Company and the consummation by the Company of the transactions
     contemplated thereby. The Merger Agreement and the Stock Option Agreement
     have been duly and validly executed and delivered by the Company and
     constitute legal, valid and binding obligation of the Company enforceable
     against the Company in accordance with their terms, except as
     enforceability may be limited by bankruptcy, insolvency, reorganization,
     moratorium or other similar laws affecting the enforcement of creditors'
     rights generally and by general equitable principles (regardless of whether
     such enforceability is considered in a proceeding in equity or at law).
 
          4.  The execution and delivery of the Merger Agreement and the Stock
     Option Agreement by the Company did not, and the performance by the Company
     of its obligations thereunder and the consummation of the transactions
     contemplated thereby will not, conflict with, result in a violation or
     breach of, constitute (with or without notice or lapse of time or both) a
     default under, result in or give to any person any right of termination,
     cancellation, modification or acceleration of, or result in the creation or
     imposition of any Lien upon any of the assets or properties of the Company
     under, any of the terms, conditions or provisions of (a) the articles of
     incorporation or regulations (or other comparable charter documents) of the
     Company, (b) any statute, law, rule or regulation, or any other Law or
     Order of any Governmental or Regulatory Authority known to us, applicable
     to the Company or any of its assets or properties, or (c) any Contract
     known to us to which the Company is a party or by which the Company or any
     of their respective assets or properties is bound.
 
          5.  No consent, approval or action of, filing with or notice to any
     Governmental or Regulatory Authority is necessary or required under any of
     the terms, conditions or provisions of any statute, law, rule or
     regulation, or any other Law or Order of any Governmental or Regulatory
     Authority known to us, applicable to the Company or any of its assets or
     properties for the execution and delivery of the Merger Agreement and the
     Stock Option Agreement by the Company, the performance by the Company of
     its obligations thereunder or the consummation of the transactions
     contemplated thereby, except as disclosed in Section 3.04(b) of the Merger
     Agreement or Schedule 3.04 thereto, all of which consents, approvals,
     actions, filings and notices have been obtained, made or given, as the case
     may be, are not subject to the satisfaction of any condition that has not
     been satisfied or waived and are in full force and effect.
 
          6.  Except as disclosed in the Company SEC Reports filed prior to the
     date hereof or in Schedule 3.08 to the Merger Agreement, to our knowledge
     there are no actions, suits, arbitrations, proceedings or Governmental or
     Regulatory Authority investigations or audits pending or threatened
     against, relating to or affecting the Company or any of its assets and
     properties which, individually or in the aggregate, could be reasonably
     expected to have a material adverse effect on the Company or on the ability
     of the Company to consummate the transactions contemplated by the Merger
     Agreement or the Stock Option Agreement.
 
     We are members of the bar of the State of                and we do not
herein express any opinion as to any matters governed by any laws other than the
laws of the State of                , the General Corporation Law of the State
of Ohio and the federal law of the United States of America.
 
     This opinion is furnished by as solely for your benefit in connection with
the consummation of the transactions contemplated by the Merger Agreement and
may not be referred to or used for any other purpose or in any other context or
otherwise relied upon by any other person, firm or corporation without our prior
written consent.
 
Very truly yours,
 
                                      72
<PAGE>   34
 
                                                                       EXHIBIT B
 
               [OPINION OF COUNSEL TO HARSCO AND ACQUISITION SUB]
 
               , 1998
 
Chemi-Trol Chemical Co.
2776 CR 69
Gibsonburg, OH 43431
 
Dear Sirs:
 
     We have acted as special counsel to Harsco Corporation, a Delaware
corporation ("Harsco"), and H-Chemi Acquisition Corp., a Pennsylvania
corporation wholly owned by Harsco ("Acquisition Sub"), in connection with the
Agreement and Plan of Merger dated as of February                , 1998 (the
"Merger Agreement"), by and among Harsco, Acquisition Sub and Chemi-Trol
Chemical Co., an Ohio corporation, and the transactions contemplated thereby.
Capitalized terms not defined herein shall have the meanings ascribed to them in
the Merger Agreement. We are rendering this opinion to you pursuant to Section
7.03(c) of the Merger Agreement.
 
     In rendering the opinions expressed below, we have examined such documents
and such corporate records of Harsco and its Subsidiaries as we have deemed
necessary as a basis for the opinion hereinafter expressed. In such examination,
we have assumed the genuineness of all signatures, the authenticity of documents
submitted to us as originals, the conformity with the original documents of all
documents submitted to us as copies and the authenticity of the originals of
such latter documents. When facts relevant to such opinions were not
independently established, we have relied upon the representations and
warranties as to factual matters made in or pursuant to the Merger Agreement and
upon certificates of government officials and of Harsco and its Subsidiaries and
their respective officers.
 
     Based upon the foregoing and having regard to legal considerations we deem
relevant, we are of the opinion that:
 
          1. Harsco is a corporation validly existing and in good standing under
     the laws of its jurisdiction of incorporation. Acquisition Sub is a
     corporation duly incorporated, validly existing and in good standing under
     the laws of its jurisdiction of incorporation.
 
          2. Each of Harsco and Acquisition Sub has full corporate power and
     authority to enter into the Merger Agreement and the Stock Option
     Agreement, to perform its obligations thereunder and to consummate the
     transactions contemplated thereby to be consummated by it. The execution,
     delivery and performance of the Merger Agreement and the Stock Option
     Agreement by each of Harsco and Acquisition Sub and the consummation by
     each of Harsco and Acquisition Sub of the transactions contemplated thereby
     to be consummated by it have been duly and validly approved by its Board of
     Directors and by Harsco in its capacity as the sole shareholder of
     Acquisition Sub, and no other corporate proceedings on the part of Harsco
     or Acquisition Sub or their shareholders are necessary to authorize the
     execution, delivery and performance of this Agreement and the Stock Option
     Agreement by Harsco or Acquisition Sub and the consummation by Harsco or
     Acquisition Sub of the transactions contemplated thereby. The Merger
     Agreement and the Stock Option Agreement have been duly and validly
     executed and delivered by Harsco and Acquisition Sub and constitute legal,
     valid and binding obligation of Harsco and Acquisition Sub enforceable
     against Harsco and Acquisition Sub in accordance with their terms, except
     as enforceability may be limited by bankruptcy, insolvency, reorganization,
     moratorium or other similar laws affecting the enforcement of creditors'
     rights generally and by general equitable principles (regardless of whether
     such enforceability is considered in a proceeding in equity or at law).
 
     We are members of the bar of the State of Pennsylvania, and we do not
herein express any opinion as to any matters governed by any laws other than the
laws of the State of Pennsylvania, the General Corporation Law of the State of
Ohio and the federal law of the United States of America.
 
     This opinion is furnished by as solely for your benefit in connection with
the consummation of the transactions contemplated by the Merger Agreement and
may not be referred to or used for any other purpose or in any other context or
otherwise relied upon by any other person, firm or corporation without our prior
written consent.
 
Very truly yours,


                                      73
<PAGE>   35
 
   
              AMENDMENT NO. 1 TO THE AGREEMENT AND PLAN OF MERGER
    
   
                           DATED AS OF APRIL 14, 1998
    
   
                                  BY AND AMONG
    
   
                              HARSCO CORPORATION,
    
   
                           H-CHEMI ACQUISITION CORP.
    
   
                                      AND
    
   
                            CHEMI-TROL CHEMICAL CO.
    
 
   
     This AMENDMENT NO. 1 TO THE AGREEMENT AND PLAN OF MERGER dated as of April
14, 1998 is made and entered into by and among HARSCO CORPORATION, a Delaware
corporation ("Harsco"), H-CHEMI ACQUISITION CORP., a Pennsylvania corporation
wholly owned by Harsco ("Acquisition Sub"), and CHEMI-TROL CHEMICAL CO., an Ohio
corporation (the "Company").
    
 
   
     WHEREAS, the parties hereto have entered into an Agreement and Plan of
Merger dated February 20, 1998 (the "Agreement") which provides at Article VIII,
Section 8.01(b)(i) for termination by either party in the event that
consummation has not occurred by April 30, 1998; and
    
 
   
     WHEREAS, the parties hereto desire to extend the date by which consummation
must occur under Article VIII, Section 8.01(b)(1) to June 30, 1998.
    
 
   
     NOW, THEREFORE, in consideration of the mutual covenants and agreements
herein contained, and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto agree as
follows:
    
 
   
          1. Article VIII, Section 8.01(b)(i) of the Agreement is hereby amended
     and restated to substitute June 30, 1998 for April 30, 1998.
    
 
   
     IN WITNESS WHEREOF, each party hereto has caused this Amendment No. 1 to be
signed by its officer thereunto duly authorized as of the date first above
written.
    
 
   
<TABLE>
<S>                                                <C>
Attest:                                            HARSCO CORPORATION
 
                                                   By:
--------------------------------------------           ----------------------------------------
Secretary                                              Name:
                                                       Title:
 
Attest:                                            H-CHEMI ACQUISITION CORP.
 
                                                   By:
--------------------------------------------           ----------------------------------------
Secretary                                              Name:
                                                       Title:
 
Attest:                                            CHEMI-TROL CHEMICAL CO.
 
                                                   By:
--------------------------------------------           ----------------------------------------
Secretary                                              Name:
                                                       Title:
</TABLE>
    
 
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