AMENDMENT NO. 1 TO CREDIT AGREEMENT

EXHIBIT 10.15

AMENDMENT NO. 1 TO CREDIT AGREEMENT

THIS AMENDMENT NO. 1 TO CREDIT AGREEMENT (this “Amendment”) is entered into as October 17, 2011, by and among the Lenders identified on the signature pages hereof (such Lenders, together with their respective successors and permitted assigns, are referred to hereinafter each individually as a “Lender” and collectively as the “Lenders”), WELLS FARGO BANK, NATIONAL ASSOCIATION, as agent for the Lenders (in such capacity, “Agent”) AMERICAN PACIFIC CORPORATION, a Delaware corporation (“Borrower”), and the domestic subsidiaries of Borrower listed on the signature pages hereof (“Guarantors”).

WHEREAS, Borrower, Guarantors, Agent, and Lenders are parties to that certain Credit Agreement dated as of January 31, 2011 (as amended, modified or supplemented from time to time, the “Credit Agreement”); and

WHEREAS, Borrower, Agent and Lenders have agreed to amend the Credit Agreement in certain respects subject to the terms and conditions contained herein;

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

1. Defined Terms. Unless otherwise defined herein, capitalized terms used herein shall have the meanings ascribed to such terms in the Credit Agreement.

2. Amendment to Credit Agreement. In reliance upon the representations and warranties of Borrower set forth in Section 6 below, the Credit Agreement is hereby amended by amending and restating Schedule 5.2 to the Credit Agreement in its entirety in the form attached as Schedule 5.2 to this Amendment.

3. Continuing Effect. Except as expressly set forth in Section 2 of this Amendment, nothing in this Amendment shall constitute a modification or alteration of the terms, conditions or covenants of the Credit Agreement or any other Loan Document, or a waiver of any other terms or provisions thereof, and the Credit Agreement and the other Loan Documents shall remain unchanged and shall continue in full force and effect, in each case as amended hereby.

4. Reaffirmation and Confirmation. Borrower and each Guarantor hereby ratifies, affirms, acknowledges and agrees that the Credit Agreement and the other Loan Documents represent the valid, enforceable and collectible obligations of Borrower and each Guarantor, and further acknowledges that there are no existing claims, defenses, personal or otherwise, or rights of setoff whatsoever with respect to the Credit Agreement or any other Loan Document. Borrower and each Guarantor hereby agrees that this Amendment in no way acts as a release or relinquishment of the Liens and rights securing payments of the Obligations. The Liens and rights securing payment of the Obligations are hereby ratified and confirmed by Borrower and each Guarantor in all respects.

5. Effectiveness. This Amendment shall become effective upon the satisfaction of each of the following conditions precedent, each in form and substance acceptable to Agent:

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(a) Each party hereto shall have executed and delivered this Amendment to Agent, and

(b) No Default or Event of Default shall have occurred and be continuing on the date hereof or as of the date of the effectiveness of this Amendment.

6. Representations and Warranties. In order to induce Agent and Lenders to enter into this Amendment, Borrower hereby represents and warrants to Agent and Lenders that, after giving effect to this Amendment:

(a) All representations and warranties contained in the Credit Agreement and the other Loan Documents are true and correct on and as of the date of this Amendment, in each case as if then made, other than representations and warranties that expressly relate solely to an earlier date (in which case such representations and warranties were true and correct on and as of such earlier date);

(b) No Default or Event of Default has occurred and is continuing; and

(c) This Amendment and the Credit Agreement, as modified hereby, constitute legal, valid and binding obligations of Borrower and Guarantors and are enforceable against Borrower and Guarantors in accordance with their respective terms.

7. Miscellaneous.

(a) Expenses. Borrower agrees to pay all Lender Group Expenses of Agent (including, without limitation, the fees and expenses of outside counsel for Agent) pursuant to the terms of the Credit Agreement in connection with the preparation, negotiation, execution, delivery and administration of this Amendment and all other instruments or documents provided for herein or delivered or to be delivered hereunder or in connection herewith. All obligations provided herein shall survive any termination of this Amendment and the Credit Agreement as modified hereby.

(b) Governing Law. This Amendment shall be a contract made under and governed by the internal laws of the State of New York.

(c) Counterparts. This Amendment may be executed in any number of counterparts, and by the parties hereto on the same or separate counterparts, and each such counterpart, when executed and delivered, shall be deemed to be an original, but all such counterparts shall together constitute but one and the same Amendment. Delivery of an executed counterpart of this Amendment by facsimile or electronic mail shall be equally effective as delivery of an original executed counterpart of this Amendment.

[signature pages follow]

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed and delivered as of the date first above written.

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Schedule 5.2

See Attached

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Schedule 5.2

Provide Agent (and if so requested by Agent, with copies for each Lender) with each of the documents set forth below at the following times in form satisfactory to Agent:

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