Stock Purchase Agreement


             This Stock Purchase Agreement dated October 30, 1996 is
        entered into by The Thermo Electron Companies Inc., a Wisconsin
        corporation (the "Seller"), and Thermo TerraTech Inc., a Delaware
        corporation (the "Buyer"), and Thermo Electron Corporation, a
        Delaware corporation, as guarantor of certain obligations of the
        Seller (the "Guarantor").  

             WHEREAS, Seller owns 100% of the issued and outstanding
        shares (the "Shares") of the capital stock of Metal Treating Inc.
        (the "Corporation"); and 

             WHEREAS, Buyer wishes to purchase, and Seller wishes to
        sell, the Shares, upon the terms and conditions set forth below; 

             NOW, THEREFORE, in consideration of the promises set forth
        below and for other good and valuable consideration, the receipt
        and sufficiency of which are hereby acknowledged, Seller and
        Buyer hereby agree as follows:

             1.   DELIVERY OF OUTSTANDING SHARES.  At the Closing (as
        defined in Section 3 hereof), and subject to the terms and
        conditions contained in this Agreement, Seller shall transfer to
        Buyer and Buyer shall acquire from Seller, all right, title and
        interest in and to the Shares, free and clear of all liens,
        encumbrances, charges, equities or restrictions.

             2.   PURCHASE PRICE.  In exchange for the Shares, and
        subject to the terms and conditions contained in this Agreement,
        Buyer shall pay to Seller at the Closing $1,600,000 in cash (the
        "Purchase Price").  

             3.   TIME AND PLACE OF CLOSING.  The closing of the
        transactions contemplated by this Agreement (the "Closing") shall
        take place immediately upon the execution of this Agreement by
        the parties hereto or at such other time and place as the parties
        may agree.  

             4.   CLOSING DELIVERIES.  At the Closing, in addition to the
        taking of such other action as may be provided in this Agreement,
        (i) Seller shall deliver certificates for the Shares to Buyer,
        duly endorsed by Seller or accompanied by duly executed stock
        powers, (ii) Buyer shall deliver the Purchase Price to Seller,
        and (iii) Seller and Buyer shall each deliver such closing
        certificates, documents and opinions of counsel, if any, as may
        be requested the other.  

             5.   REPRESENTATIONS AND WARRANTIES OF SELLER.  Seller
        represents and warrants to Buyer that, as of the Closing Date:
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                  (a)  Organization and Qualification.  Seller is a
        corporation validly existing and in good standing under the laws
        of the State of Wisconsin.  

                  (b)  Authority.  The execution and delivery of this
        Agreement, and the consummation of the transactions contemplated
        hereby to be performed by Seller, have been duly and validly
        authorized by all necessary corporate action on the part of
        Seller.  This Agreement constitutes the valid and binding
        obligation of Seller enforceable against Seller in accordance
        with the terms hereof.  

                  (c)  Ownership of Shares; Authority to Transfer.  The
        Shares are not encumbered and are freely transferable by Seller.
        Seller holds good and marketable title to the Shares to be
        transferred to Buyer hereunder and no third party is entitled to
        claim any right thereto or make any claim thereon.  The transfer
        of the Shares to Buyer pursuant to this Agreement will vest in
        Buyer title to the Shares, free and clear of all liens, claims,
        equities, options, calls, voting trusts, agreements, commitments
        and encumbrances whatsoever.  

                  (d)  Buyer acknowledges that, prior to the date of this
        agreement, it has managed the corporation for the benefit of
        seller and that buyer's knowledge of the business, assets and
        liabilities of the corporation is superior to that of the seller.
        accordingly, Seller disclaims any representations or warranties
        with respect to the Corporation or ITS Business, assets and/or
        liabilities.  THE TRANSFER OF THE SHARES TO BUYER IS  MADE "AS
        IS" AND ALL WARRANTIES OF CONDITION, MERCHANTABILITY, QUALITY OR
        FITNESS FOR USE, OR ANY OTHER WARRANTY, EXPRESSED OR IMPLIED,
        WITH THE EXCEPTION OF WARRANTIES OF TITLE SET FORTH HEREIN ARE
        HEREBY DISCLAIMED.

             6.   REPRESENTATIONS AND WARRANTIES OF BUYER.  Buyer
        represents and warrants to Seller that, as of the Closing Date:

                  (a)  Organization and Qualification.  Buyer is a
        corporation validly existing and in good standing under the laws
        of the State of Delaware.  

                  (b)  Authority.  The execution and delivery of this
        Agreement, and the consummation of the transactions contemplated
        hereby to be performed by Buyer, have been duly and validly
        authorized by all necessary corporate action on the part of
        Buyer.  This Agreement constitutes the valid and binding
        obligation of Buyer enforceable against Buyer in accordance with
        the terms hereof.  

             7.   ASSUMPTION OF LIABILITY BY SELLER.  Notwithstanding any
        other provision in this Agreement, as between Buyer and Seller,
        Seller hereby assumes, and agrees to hold the Corporation and
        Buyer harmless from and against, any liabilities now existing or
        which the Corporation or the Buyer may incur hereafter as a

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        result of the existence of certain contamination identified in an
        environmental site assessment report dated August 30, 1996 with
        respect to certain property adjacent to property owned by the
        Corporation; provided, however, that Seller does not assume any
        liability for any contamination which may have been caused, or
        which may in the future be caused by acts or omissions of the
        Corporation itself.  The Guarantor hereby guarantees the
        obligations of the Seller as set forth in this Section 7.

             8.    FURTHER ASSURANCES.  From time to time and at any time
        after the Closing, and without further expense to the requesting
        party, each party will execute and furnish to the requesting
        party all documents and will do or cause to be done all other
        things that the requesting party may reasonably request in order
        to give full effect to this Agreement and to effectuate the
        intent of the parties.

             9.  CONFIDENTIALITY OF INFORMATION.  Seller and Guarantor
        agree that (a) they have obtained confidential and proprietary
        information about the Corporation, including, but not limited to,
        the Corporation's business plans, strategies, customer lists, and
        financial and statistical information and (b) they will not
        disclose, directly or indirectly, such information or use it for
        any purpose other than for Buyer's benefit.  

             10.  SUCCESSORS AND ASSIGNS.  Each and every provision
        hereof shall be binding upon and shall inure to the benefit of
        the parties and their respective successors and assigns.

             11.  ENTIRE AGREEMENT.  This Agreement constitutes the full
        and complete agreement of the parties hereto with respect to the
        subject matter hereof.  

             12.  CAPTIONS.  Titles or captions of sections contained in
        this Agreement are inserted only as a matter of convenience and
        for reference, and in no way define, limit, extend or describe
        the scope of this Agreement or the intent of any provision
        hereof.  

             13.  COUNTERPARTS.  This Agreement may be executed in
        counterparts, all of which together shall for all purposes
        constitute one Agreement, binding on the parties hereto
        notwithstanding that such parties have not signed the same
        counterpart.  

             14.  APPLICABLE LAW.  This Agreement and the rights and
        obligations of the parties hereunder shall be governed by and
        interpreted, construed and enforced in accordance with the laws
        of the Commonwealth of Massachusetts. 

             15.  CREDITORS.  None of the provisions of this Agreement
        shall be for the benefit of or enforceable by any creditor of any
        party hereto.

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             IN WITNESS WHEREOF, the parties have executed this Agreement
        on October 30, 1996.  


        SELLER:                            BUYER:

        THE THERMO ELECTRON                THERMO TERRATECH INC.         
        COMPANIES INC.

        By:  John A. Wielgosz           By:     John P. Appleton   
             John A. Wielgosz                   John P. Appleton
             Treasurer                          President




        GUARANTOR:

        THERMO ELECTRON CORPORATION

        By:  Jonathan W. Painter  
             Jonathan W. Painter
             Treasurer