DSHW-2008-025778 - 0901a068801e25af

David P. Gosen, P.E.
Director, Environmental Services
ATK Launch Systems – Promontory
P.O. Box 707
Brigham City, UT 84302-0707

RE: Class 1 Post-Closure Permit Modification Approval
Tracking Number MOD08.02547
ATK Launch Systems - Promontory Facility, EPA I.D. #UTD009081357

Dear Mr. Gosen:

The Division of Solid and Hazardous Waste has completed its review of your request, dated July 17, 2008, to modify ATK’s Post-Closure Permit to incorporate a new groundwater sampling
procedure. This is a Class I modification that requires prior approval by the Executive Secretary of the Utah Solid and Hazardous Waste Control Board.

Based on the results of the HydraSleeve sampler evaluation report and the revisions ATK has made to the Sampling and Analysis Plan regarding the new sampling procedure (Attachment 3
of the Post-Closure Permit), ATK’s modification request is hereby approved.

Enclosed with this letter is the modified Sampling and Analysis Plan (SAP). All of the necessary changes to the Post-Closure Permit for adding the new sampling procedure are contained
within the SAP. Please replace the original SAP in the Post-Closure Permit with the enclosed SAP (note the modification date of September 3, 2008 in the document’s footer).

In accordance with 40 CFR 270.42(a)(ii), a notice of the permit modification must be sent to all persons on the facility mailing list within 90 calendar days after the modification request
is approved. The facility mailing list is maintained by this office.

If you need a copy of the facility mailing list or if you have any questions, please contact Jeff Vandel at [phone].

Sincerely,

ORIGINAL DOCUMENT SIGNED BY DENNIS R. DOWNS ON 9/8/08

Dennis R. Downs, Executive Secretary
Utah Solid and Hazardous Waste Control Board

DRD\JV\tjm

c: Paul Hancock, ATK Launch Systems
Lloyd C. Berentzen, MBA Health Officer, Bear River Health Department

File to: ATK Launch Systems - Promontory

September 8, 2008
Page 2
TN200800761

September 8, 2008

288 North 1460 West • Salt Lake City, UT
Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
TN200800761 Printed on 100% recycled paper

State of Utah

Department of Environmental Quality

Richard W. Sprott
Executive Director

DIVISION OF SOLID AND HAZARDOUS WASTE
Dennis R. Downs
Director

JON M. HUNTSMAN, JR.
Governor

GARY HERBERT
Lieutenant Governor