DSHW-2006-009152 - 0901a068801627a3

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

RE: Human Health Risk Assessment and Remediation Plans for Groundwater
Process Supply Well TCC3A
ATK Launch Systems - Promontory Facility, EPA I.D. #UTD009081357

Dear Mr. Gosen:

The Division of Solid and Hazardous Waste (the Division) has completed its review of the revised Human Health Risk Assessment that was prepared by EarthFax Engineering and submitted
to our office on October 11, 2006. The risk assessment was conducted to evaluate the risk to human health from exposure to contaminated groundwater obtained from process supply well
TCC3A. Based on information provided by ATK, this well supplies water for various processes at Plant 3 and the restrooms at Building M-201. Water samples collected from the well have
consistently shown the presence of trichloroethlylene (TCE) and perchlorate.

The Division concurs with the findings of the risk assessment which show that the concentrations of contaminants that have been observed in groundwater do not pose a risk to human health,
provided that it is not used as a source for drinking water. It has been verified that signs have been posted in the restrooms at Building M-201 warning people not to drink the water.
It was also observed that bottled drinking water is provided. The other exposure pathways that exist were appropriately evaluated in the risk assessment; therefore, our initial concern
regarding the use of contaminated groundwater appears to be adequately addressed.

It is understood that ATK plans to continue to use well TCC3A as the water source for Plant III. As has been discussed with members of your staff, treatment of the groundwater is required
prior to storage and use due to the presence of a listed hazardous waste constituent (TCE). Please submit the plans for groundwater treatment to the Division no later that February
1, 2007. If you have any questions, please contact Jeff Vandel at [phone].

Sincerely,

ORIGINAL DOCUMENT SIGNED BY DENNIS R. DOWNS ON 12/28/06

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

DRD\JV\tm

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

File to: ATK Launch Systems - Promontory

December 28, 2006
Page 2

December 28, 2006

TN200601537

288 North 1460 West • PO Box 144880 • Salt Lake City, UT 84114-4880 • phone [phone] • fax [phone]
T.D.D. [phone] • www.deq.utah.gov

State of Utah

Department of Environmental Quality

Dianne R. Nielson, Ph.D.
Executive Director

DIVISION OF SOLID AND HAZARDOUS WASTE
Dennis R. Downs
Director

JON M. HUNTSMAN, JR.
Governor

GARY HERBERT
Lieutenant Governor