<PAGE>
                                                                   Exhibit 10.12

CoreStates Bank, N.A.
2240 Butler Pike
Plymouth Meeting PA 19462
Fax 610 834 2089


                                          [LOGO OF CORESTATES BANK APPEARS HERE]

                                January 17,1998


Total Containment, Inc.
422 Business Center
A 130 North Drive
P.O. Box 939
Oaks, PA 19456

Attention: Pierre Desjardins
           President and CEO


Gentlemen:

       CoreStates Bank is pleased to make the following commitment available:

Borrower(s):              Total Containment, Inc., TCI Environment NV/Sa,
------------              Rene Morin, Inc., and American Containment, Inc.
                          ("Borrower")


Lender:                   CoreStates Bank, N.A. ("Bank")
-------
     
Loan Amount:              $10,000,000 Secured Revolving Line of Credit.
------------

Use of Proceeds:          Finance current assets and the expenses associated 
----------------          with replacing defective pipe manufactured by Dayco
                          Corporation and general corporate purposes.

Loan Payments and
-----------------
Advances:                 All remittances to be directed to a CoreStates
---------                 account. Collected funds will be applied to reduce
                          outstandings under the Loan Facility on a direct
                                                                    ------
                          application basis. Borrowing certificates are to be
                          -----------
                          submitted to the Bank on a weekly basis. Each
                          certificate will indicate a
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January 17, 1998
Total Containment, Inc.                2


                        current accounts receivable balance and the previous 
                        month-end inventory amount.

Maturity Date:          June 30, 1999
--------------

Collateral:             First, perfected, security interest in all of borrower's
-----------             existing and future accounts, inventory, general
                        intangibles, and other business assets as defined in
                        current documentation. This facility will be cross-
                        collateralized with all other loans extended to the
                        Company by the Bank.

Borrowing Formula:      Advances will not exceed the lesser of $10,000,000,
------------------      or the sum of the following:

                        Accounts: Loans of up to eighty percent (80%) of the net
                        ---------
                        amount of eligible accounts receivable of the Company.
                        Eligible accounts receivable will be determined by the
                        Bank pursuant to general criteria which will be set
                        forth in the loan documentation. Eligible accounts
                        receivable shall exclude accounts which are unpaid more
                        than sixty (60) days past the original due date thereof,
                        but in any event are unpaid more than ninety (90) days
                        from the original invoice date, and accounts owed by an
                        account debtor which has more than fifty percent (50%)
                        of the aggregate amount thereof unpaid more than 90 days
                        past the original invoice date thereof. In addition, all
                        otherwise eligible receivables will exclude accounts
                        which are contra accounts, poor credits, employee or
                        affiliate accounts receivable, and those other accounts
                        which do not constitute collateral acceptable for
                        leading purposes as outlined in current documentation.

                        Subject to the Bank's determination, foreign accounts
                        receivable payable in the United States in U.S. dollars
                        may be eligible accounts receivable if a letter of
                        credit has been issued with respect to such foreign
                        accounts receivable or credit insurance satisfactory to
                        the Bank covers them or the Bank is otherwise satisfied
                        with the creditworthiness of the account debtor and its
                        ability to collect the foreign accounts receivable. Any
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January 17, 1998
Total Containment, Inc.                 3


                       advance rate with respect to foreign accounts receivable
                       will be determined on an account by account basis.

                       Inventory: Loans of up to twenty-five percent (25%) of
                       --------- 
                       the value of eligible inventory of the Company, valued at
                       the lower of cost or market, as determined by the Bank,
                       with cost determined under the first-in-first-out method.
                       Eligible inventory will be determined pursuant to general
                       criteria which will be set forth in the loan
                       documentation. Generally, eligible inventory will exclude
                       packaging, slow-moving or obsolete inventory, and those
                       other items which do not constitute collateral acceptable
                       for lending purposes as outlined in current
                       documentation.

                       The inventory advance rate will temporarily increase to
                       35% from 7/31/98 through 3/31/99. At 4/30/99, the
                       inventory advance rate will revert to 25%. Inventory
                       advances will not exceed $2,500,000 during the 25%
                       advance rate periods and $3,300,000 during the 35%
                       periods. The advance rates referenced above are
                       conditional upon the Borrower's meeting their final
                       projections as measured by the Financial Covenants.

Guarantor(a):          None
------------

Origination Fee:       $50,000, payable at closing.        
---------------

Fees:                  .25% of the unused portion of the revolving line of 
----                   credit, payable quarterly in arrears.

Interest Rate:         CoreStates Bank, N.A.'s Prime Rate plus 1/2%, floating.
-------------          Performance based pricing covenants will be incorporated
                       into the agreement based on performance parameters to be
                       achieved in the nine months ending 9/30/98.
        
                       Letters of Credit: 1.50% commission per annum.


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January 17, 1998
Total Containment, Inc.                 4

Financial 
---------
Covenants:              Certain Financial Covenants to be mutually agreed to
---------               by Bank and Borrower

Non-Financial 
-------------
Covenants:              Customary for transactions of this type, such as
---------               financial reporting, payment of taxes, compliance with
                        laws, maintenance of corporate existence, maintenance of
                        insurance, no material adverse change, no change in 
                        ownership or basic business, such as mergers, 
                        acquisitions, guarantees, other liens and other
                        indebtedness. 

Events of Default:      Customary for this type of facility, including but not
-----------------       limited to:

                        1)  Failure to pay principal, interest, or fees when
                            due;
                        2)  Noncompliance with covenants;
                        3)  Any representations or warranty shall prove to be
                            incorrect, false or misleading in a material respect
                            when made;
                        4)  Insolvency, bankruptcy.

Cross Default:          Loan will be cross defaulted with all other loans to
-------------           Borrower from Bank.

Conditions Precedent:   1)  Documentation satisfactory to the Bank and its
--------------------        counsel. Documentation will include an agreed-upon
                            format for a warranty reserve/expenditure report.
                        2)  Subject to receipt and satisfactory review by the
                            Bank of a Certificate of the Borrower that describes
                            in sufficient detail the components of the
                            $18,000,000 Reserve taken as of 9/30/97. Borrower
                            shall provide to the Bank a monthly report which
                            details the Warranty Expenditures for the current
                            period and year to date and reconciles to the
                            Certificate referenced above. Any additional
                            increases to the Dayco Warranty Reserve in excess of
                            $500,000 on a cumulative basis shall constitute a
                            default.
                        3)  Borrowing Base Formula availability at closing of
                            $500,000.
                                            

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January 17, 1998
Total Containment, Inc.                5


                                4)  Legal and out-of-pocket expenses incurred by
                                    the Bank to document this transaction shall
                                    be for the account of the Borrower.

                                5)  Satisfactory review of Borrower's books and 
                                    records by the Bank's collateral auditors.

                                6)  Fire and hazard insurance on all personal
                                    and real property with the Bank named Lender
                                    Loss Payee as its interests may appear on
                                    all policies of insurance covering assets in
                                    which the Bank has a security interest.

                                7)  No material adverse change in the financial 
                                    condition of Borrower.

                                8)  Satisfactory results in our continuing due
                                    diligence including customary bank, trade,
                                    and professional checkings.

                                9)  Borrower will utilize CoreStates as primary 
                                    bank of account.

                                10) The existing $1,500,000 equipment revolving
                                    facility will be reduced to $1,058,000, of
                                    which $808,000 has been drawn down as of
                                    this date. This limit anticipates financing
                                    80% of the purchase and installation of
                                    equipment (subject to terms in the existing
                                    agreements).

                                11) Subject to the receipt and satisfactory
                                    review by the Bank of the Borrower's monthly
                                    financial statements, including Balance
                                    Sheet, Income Statement and Cash Flow
                                    Statement for the years 1998 and 1999.

Financial Reporting:            1)  Borrower will deliver to Bank its annual
--------------------                financial statements and 10-K within 90 days
                                    of the close of its fiscal year; Quarterly
                                    financial statements and 10-Q, within 45
                                    days after the end of each quarter; and
                                    Monthly financial statements within 30 days
                                    of each month end. The annual financial
                                    statements will be audited by an independent
                                    accounting firm acceptable to the Bank.

                                2)  Borrower will deliver to the Bank monthly,
                                    within 15 days of month end: accounts
                                    receivable and accounts payable agings, a
                                    borrowing base summary certificate, and a
                                    warranty reserve expenditure/progress
                                    report.
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January 17, 1998
Total Containment, Inc.                 6



Governing Law:          Commonwealth of Pennsylvania
-------------

Collateral Audits:      Two (2) audits will be performed in the first twelve
-----------------       months by Bank auditors. Cost of said audits to be
                        absorbed by the Borrowers Per audit, as follows:

                        - 100% of amounts up to $6,000; plus
                        - 50% of amounts over $6,000 but less than $10,000.
                        - Borrowers will not be responsible for any amounts in 
                          excess of $10,000.
                        Bank reserves the right to conduct additional 
                        collateral audits at its discretion.

This letter is intended solely for the Borrower, is not assignable by the 
Borrower, and shall not benefit or be relied upon by any third party without 
prior written consent of the Bank.

If the foregoing is satisfactory, please evidence that fact, intending to be 
legally bound hereby, by having the copy of this letter enclosed for that 
purpose signed by all parties indicated and returning the executed copy to us. 
Unless the Bank receives acceptance of this letter by the Borrower on or before 
February 20, 1998, the terms set forth herein shall, at the option of the Bank, 
become null and void.
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January 17, 1998
Total Containment, Inc.                 7


We at CoreStates are very pleased about this opportunity and look forward to a 
mutually beneficial relationship between Total Containment, Inc. and CoreStates 
Bank.

Very truly yours,


CoreStates Bank, N.A.


By: /s/ Charles H. O'Donnell V.P. for
   ----------------------------
   Charles H. O'Donnell
   Vice President


CHO/sjr


ACCEPTED AND AGREED, INTENDING TO BE LEGALLY BOUND
HEREBY ON February 20, 1998.
          -----------

Total Containment, Inc.


By: /s/ Pierre Desjardins
   ----------------------------
   Pierre Desjardins, President


TCI Environment, NV/SA


By: /s/ Pierre Desjardins
   ----------------------------
   Pierre Desjardins, President


Rene Morin, Inc.


By: /s/ Jeffrey Boehmer
   ----------------------------
   Jeffrey Boehmer, President


American Containment, Inc.


By: /s/ Jeffrey Boehmer
   ----------------------------
   Jeffrey Boehmer, Secretary