DSHW-2004-007780 - 0901a06880164eb0 (4)

January 5, 2005

Ray Adams
928 East 100 North
Brigham City, UT 84302

RE: Migration of Contaminated Groundwater from the ATK Thiokol Inc. – Promontory Facility

Dear Mr. Adams:

This letter is in response to your inquiry made on December 21, 2004, regarding the migration of contaminated groundwater from the ATK Thiokol Inc. – Promontory facility (Thiokol) to
the shallow aquifer underlying your property. As you know, Thiokol installed eight monitoring wells on your property. The Division of Solid and Hazardous Waste (the Division) requested
that Thiokol install the additional wells in order to define the nature and extent of groundwater contamination southeast of the facility. Thank you for your cooperation in allowing
Thiokol to install these monitoring wells.

The new wells, designated H-1 through H-8, have been sampled on two occasions, in the Fall of 2003 and the Spring of 2004. These water samples were analyzed for contaminants that are
known to be present in the shallow aquifer underlying the Thiokol facility. There are two primary contaminants present in the aquifer that have been identified – perchlorate and trichloroethene.
The analytical results for these contaminants are summarized below in Tables 1
and 2.

Table 1. Perchlorate
Water Sample Results - (g/L
Well Spring ‘02 Fall ‘02 Spring ‘03 Fall ‘03 Spring ‘04 BC-2 3.8 NS NS NS NS EW-6 NS 9710 NS 10900 7740 H-1 NA NA NA <5 <5 H-2 NA NA NA <5 <5 H-3 NA NA NA <5 <5 H-4 NA NA NA 55 63.5 H-5 NA NA NA 17 11.5 H-6 NA NA NA <5 <5 H-7 NA NA NA <5 <5 H-8 NA NA NA <5 <5

NS – well wasn’t sampled during the semi-annual event
NA – wells had not yet been installed

Table 2. Trichloroethene (TCE)
Water Sample Results - (g/L

Well Spring ‘02 Fall ‘02 Spring ‘03 Fall ‘03 Spring ‘04 BC-2 1.1 NS NS NS NS EW-6 NS 128 NS 92 41.5 H-1 NA NA NA 7.2 4.2* H-2 NA NA NA <0.6 3.3* H-3 NA NA NA <0.6 1.9* H-4 NA NA NA 5.0 4.9* H-5 NA NA NA 2.9 1.6* H-6 NA NA NA 10.0 7.9* H-7 NA NA NA 1.5 3.6* H-8 NA NA NA 4.6 4.0*

* results are estimated values due to analytical quantitation limits
NS - well wasn’t sampled during the semi-annual event
NA - wells had not yet been installed

These monitoring results indicate that very low levels of trichloroethene likely exist in the eight H-series wells. Perchlorate was detected, in relatively low levels as compared to
well EW-6, in wells H-4 and H-5 only (please refer to the monitoring well location map provided by Thiokol). The old well referred to as EW-6 (existing well #6) is contaminated with
significant levels of trichloroethene and high concentrations of perchlorate.

Due to the release of contaminants to the groundwater, Thiokol is required (in accordance with the State of Utah, Hazardous Waste Management Rules) to institute a corrective action program
to ensure that the groundwater protection standard is not exceeded. The groundwater protection standard is established in a Post-Closure Permit that is issued to Thiokol by the Division.
The State of Utah, Hazardous Waste Management Rules allow for cleanup standards to be based on the level of risk posed by the contamination. The level of risk posed is calculated by
looking at exposure to the contamination by humans and the environment.

Thiokol plans to address groundwater contamination issues by completing the following steps: installing additional monitoring wells to better define the nature and extent of contamination;
construct groundwater flow and contaminant transport models to predict how far – and at what concentration – the groundwater contaminant plumes will migrate; conduct human health and
ecological risk assessments to establish the risks posed by the contamination; develop a corrective action plan based on the results of the previous steps.

A schedule for completing these steps has been developed. Thiokol is currently finishing up with the installation of additional monitoring wells, and has started work on the groundwater
modeling. A date of May 2005 has been proposed for completion of the groundwater model and risk assessment, however, at this time it appears unlikely that the risk assessment will be
completed by this date. The corrective action plan is scheduled to be complete by May of 2006.

You indicated over the telephone that a well exists north of well EW-6 that is used for watering stock. The Division will be in contact with Thiokol to see what data exists for this
well and will make plans to sample it in the near future. If you have any questions please contact Jeff Vandel at [phone].

Sincerely,

ORIGINAL DOCUMENT SIGNED BY DENNIS R. DOWNS ON JANUARY 5, 2005

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

DRD/JV/ts

c: Paul Hancock, Manager, Environmental Remediation, ATK Thiokol Inc.
Lloyd C. Brentzen, MBA, Health Off, , Bear River Health Dept.

TN200401520
file: ATK Thiokol Inc. - Promontory

January 5, 2004
Page 2

State of Utah

Department of Environmental Quality

Dianne R. Nielson, Ph.D.
Executive Director

DIVISION OF SOLID & HAZARDOUS WASTE
Dennis R. Downs
Director

OLENE S. WALKER
Governor

GAYLE F. McKEACHNIE
Lieutenant Governor

TN200401520.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