DSHW-2003-008315 - 0901a06880160397

September 11, 2003

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

RE: Proposed Locations for Groundwater Monitoring Wells, ATK Thiokol Propulsion – Promontory Facility, #UTD009081357

Dear Mr. Hancock:

This letter is in response to your correspondence dated August 20, 2003 regarding proposed groundwater monitoring well locations. The Division of Solid and Hazardous Waste (the Division)
is in agreement with the proposed well locations. Groundwater monitoring at these points will help in defining the extent of contaminant plumes at the facility. Depending on the results
of drilling and sampling the third and fourth wells proposed (east of well TCC2 and adjacent to well M114-B1), the question about regional aquifer migration to the east could potentially
be resolved. If the additional data provided by these wells does not resolve this question, an additional well or wells may be needed.

As stated in Appendix I to 40 CFR §270.42 (incorporated by reference in R315-3-4.3), “changes in the number, location, depth, or design of upgradient or downgradient wells of a permitted
groundwater monitoring system” requires a Class 2 permit modification at the request of the permittee. Therefore, Thiokol must submit a modification request to the Executive Secretary
as outlined under 40 CFR §270.42 (b). It is anticipated that the permit modification request will be approved after the 60-day public comment period and meeting are conducted.

In addition, the Division would like to remind Thiokol that although the Post-Closure Permit is currently in the process of being reissued, the original permit conditions remain in affect
until the permit is reissued. Permit conditions that apply to the addition of new monitoring wells are summarized below.

Permit Condition Description V.D.1.b. Requirements on the construction of monitoring wells V.D.1.i. The permittee may add wells to the monitoring well system only upon approval of
the Executive Secretary. Permit Condition Description V.D.1.l. The permittee shall provide for the proper disposal of contaminated groundwater generated during sampling and development
of new wells. V.D.2.a. Well construction shall follow the guidelines developed in the most recent Technical Enforcement Guidance Document (TEGD). V.D.2.b. The Executive Secretary’s
role in approving the addition of monitoring wells and the requirement for a Class 2 permit modification V.D.2.e. Monitoring well completion reports shall be submitted to the Executive
Secretary within 90 days after completion of the wells. VI.E.1. If TEGD guidelines are not followed when constructing new monitoring wells, the construction specifications must be approved
by the Executive Secretary prior to installation of the wells. VI.E.2. Requirements for disposal of contaminated groundwater VI.E.2.a. Disposal of contaminated groundwater at the
M-705 wastewater treatment facility

Please review the permit conditions outlined above to ensure that they are complied with during this change to the groundwater monitoring system. As stated above, Thiokol must submit
a modification request to the Executive Secretary as outlined under 40 CFR §270.42 (b). Please submit the modification request within 30 days of the receipt of this letter. In addition,
please include a monitoring well installation plan with the modification request that addresses disposal of contaminated water generated by installing or sampling wells, well design
and construction, a description of what will be included in the monitoring well completion report and a schedule for its submittal.

If you have any questions, please contact Jeff Vandel at 538-9413. Thank you for your cooperation.

Sincerely,

Original Document Signed by Dennis R. Downs on 9/12/03

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

DRD\jv\kk

c: John C. Bailey, M.D., M.S.P.H., Health Officer/Director, Bear River Health Dept.
Mary Wu, USEPA Region VIII

TN200301962.doc
file to: Thiokol - Promontory
September 11, 2003
Page 2

Michael O. Leavitt
Governor
Dianne R. Nielson, Ph.D.
Executive Director
Dennis R. Downs
Director

Department of Environmental Quality
Division of Solid and Hazardous Waste
288 North 1460 West
P.O. Box 144880
Salt Lake City, Utah 84114-4880
[phone]
[phone] Fax
[phone] T.D.D.
www.deq.utah.gov