DSHW-2006-006507 - 0901a068801617e4

Paul Hancock, Manager
Environmental Remediation
ATK Thiokol Inc. – Promontory
P.O. Box 707
Brigham City, UT 84302-0707

RE: Groundwater Contamination at Process Supply Well TCC3A, ATK Thiokol – Promontory Facility, EPA ID #009081357

Dear Mr. Hancock:

This letter is in regard to recent conversations that you have had with staff members of the Division of Solid and Hazardous Waste (the Division) concerning the contamination that has
been monitored in process supply well TCC3A. As you recently pointed out in one of these conversations, and reported in the January, 2006 Groundwater Monitoring Report, the most current
groundwater sample results for the well indicate that trichloroethylene (TCE) was detected at 10.7 µg/L and perchlorate was detected at 42.7 µg/L. These are the highest concentrations
of the two contaminants that have been detected in the well.

You also indicated that well TCC3A, among other uses, supplies water to a number of sinks, showers and eye wash stations at a few locations at Plant III. The water from these locations
is disposed of through two septic and drainfield systems. The Division is concerned about the potential for human exposure to these contaminants and the subsequent disposal of contaminated
water through the septic systems.

Discussions were held between Thiokol and the Division approximately ten years ago regarding the contamination of well TCC3A, and were summarized by Thiokol in a letter dated August
14, 1996. The main issue that was discussed was whether Thiokol could continue to use water pumped from the well for process and fire fighting purposes. At that time, the concentration
of TCE detected in the well was 2.8 µg/L. It was determined by the Division that the low level of contamination present didn’t appear to present a threat to human health or the environment
and that the water could be used for the stated purposes. At the time, the Division was not aware, however, that these purposes included supplying water for sinks, showers and eye wash
stations.
Based on the results of samples collected from well TCC3A since 1989, it appears that contamination has steadily increased. The analytical results that have been obtained for the well
are summarized in the table below:

Well TCC3A Analytical Results for TCE and Perchlorate

DATE TCE (µg/L) PERCHLORATE (µg/L) March 1989 below detection no sample September 1992 0.85 no sample October 1992 below detection no sample December 1993 1.2 no sample February
1996 1.9 no sample May 1996 2.8 no sample May 2001 7.2 36 October 2002 8.7 38 November 2005 10.7 42.7

It is understood that well TCC3A is currently the only source of water for Plant III. However, real potential exists for human exposure to these contaminants. The Division hereby requests
that Thiokol respond to this letter, within 14 days of its receipt, by explaining how it intends to address this issue. If you have any questions, please contact Jeff Vandel at 538-6170.

Sincerely,

ORIGINAL DOCUMENT SIGNED BY DENNIS R. DOWNS ON 3/27/06

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

DRD\JV\tm

c: Lloyd C. Berentzen, M.B.A., Health Officer, Bear River Health Department

File to: ATK Thiokol Inc. - Promontory

March 27, 2006
Page 2

March 27, 2006

TN200600338.doc
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