EXHIBIT 10.18.1

THIS SECOND AMENDMENT AGREEMENT (1997 L/C) (this “Agreement”) is dated as of
May 1, 2007, by and between West Valley MRF, LLC, a California limited liability
company (the “Borrower”) and Union Bank of California, N.A. (the “Bank”) and is
being entered into in connection with the following:

A. The Bank and the Borrower are party to a Reimbursement Agreement dated as of
June 1, 1997 as amended by that certain Extension and Amendment Agreement dated
as of May 5, 2005 (as so amended, the “Reimbursement Agreement”), pursuant to
which the Bank has issued its Irrevocable Letter of Credit No. 306S230625, dated
June 25, 1997 (as heretofore amended, the “Letter of Credit”) in favor of BNY
Western Trust Company, as Trustee. Capitalized terms used herein without
definition shall have the respective meanings ascribed thereto in the
Reimbursement Agreement.

B. Under Section 1(g) of the Reimbursement Agreement, the Borrower is required
to make monthly deposits into the Deposit Account so that the aggregate annual
amount of such deposits is equal to the respective amounts shown on the bond
amortization/reimbursement deposit schedule attached as Exhibit B to the
Reimbursement Agreement. The Borrower has requested that the bond
amortization/reimbursement deposit schedule be amended to reduce both the
monthly deposit requirement and the amount required for the annual partial
redemption of Bonds. The Bank has approved this request subject to the terms and
conditions hereinafter set forth.

NOW, THEREFORE, the Bank and the Borrower do hereby agree as follows:

1. Effective as of the Effective Date (as defined below), the Bank and the
Borrower agree that the bond amortization/reimbursement deposit schedule
attached as Exhibit B to the Reimbursement Agreement is hereby deleted and is
replaced by a new Exhibit B in the form attached hereto. This Agreement and such
written consent may be executed in counterparts and the Bank may accept
execution of counterparts via facsimile transmission.

2. The Borrower hereby represents and warrants to the Bank as follows:

(a) No Default or Event of Default under the Reimbursement Agreement, the Deed
of Trust or any Related Document has occurred and is continuing;

(b) The execution, delivery and performance by the Borrower of this Agreement
have been duly authorized by all necessary company action and do not and will
not require any registration with, consent or approval of, notice to or action
by, any person (including any governmental agency) in order to be effective and
enforceable. The Deed of Trust constitutes the legal, valid and binding
obligation of the Borrower, enforceable against it in accordance with its terms,
without defense, counterclaim or offset; and

(c) All representations and warranties of the Borrower under the Reimbursement
Agreement and the Deed of Trust are true and correct fully as if made on the
date hereof.

3. When both of the following conditions precedent have been satisfied or waived
by the Bank, this Agreement will be deemed effective as of May 1, 2007
(“Effective Date”):

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(a) The Bank has received from the Borrower a counterpart of this Agreement duly
executed by the Borrower together with a fully executed copy of a Guarantors’
Acknowledgment and Consent in form and substance satisfactory to the Bank; and

(b) All representations and warranties of the Borrower contained herein and in
the Reimbursement Agreement are true and correct as of the Effective Date and no
Event of Default, and no event which with notice or lapse of time or both would
become an Event of Default, shall have occurred and be continuing under the
Reimbursement Agreement.

4. This Second Amendment Agreement may be executed in multiple counterparts
which taken together shall constitute one and the same document. As modified
hereby, the Reimbursement Agreement is hereby ratified, approved and confirmed
and remains in full force and effect.

IN WITNESS WHEREOF, the Bank and the Borrower have executed this Second
Amendment Agreement effective as of the date first set forth above.

 

WEST VALLEY MRF, LLC,

a California limited liability company

By:   Kaiser Recycling, LLC,   a Delaware limited liability company, member  
By:   /s/ James F. Verhey     Name: James F. Verhey     Title: Vice President
By:  

West Valley Recycling & Transfer, Inc.,

a California corporation, member

  By:   /s/ Cole Burr     Name: Cole Burr     Title: President

 

UNION BANK OF CALIFORNIA, N.A. By:   /s/ Myra Juetten   Name: Myra Juetten  
Title: Vice President

 

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EXHIBIT B

REIMBURSEMENT DEPOSIT SCHEDULE

 

Twelve Months Ending in June

  

Annual DSR Deposit Amount

2007

   630,000

2008

   630,000

2009

   630,000

 

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