DSHW-2012-004206 - 0901a068802eaaf9 (4)

February 3, 2012

David Gosen, P.E.
Director, Environmental Services
ATK Launch Systems Inc.
P.O. Box 707
Brigham City, Utah 84302

Re: Corrective Action for Installation Restoration Program (IRP)
Former U.S. Air Force Plant 78, Stage 2
ATK Launch Systems, Promontory Facility, Brigham City, Utah
UTD009081357

Dear Mr. Gosen:

The Division of Solid and Hazardous Waste has completed its review of the subject document. Of the seven areas of concern investigated, Building M-585 (French Drain Site) appears to
be the only site where soil and groundwater contamination from past waste management practices has not yet been sufficiently characterized. Our comments are two-fold:

1) The local groundwater flow direction at Building M-585 has not been defined. Three piezometers were installed at the site (P-2, P-6, and P-7). However, it appears that piezometer
P-2 taps into a different, deeper, confined groundwater bearing zone than piezometers P-6 and P-7 (which tap into the uppermost perched zone). Therefore, in order to accurately determine
groundwater flow direction in the uppermost perched zone, at least one additional piezometer will have to be installed, preferably in a location which maximizes a triangular area with
respect to piezometers P-6 and P-7.

2) The soil vapor study, conducted in two phases to the southwest of Building M-585, is based on the PETREX, ion flux, indicator method. It appears that quantitative soil vapor concentration
estimates are non-existent. Therefore, in order to model potential indoor air concentrations to receptors in this area, which, since the perched aquifer is less than 100 feet below
grade, is required as part of the human health risk assessment, a supplemental soil vapor study consisting of a mixture of passive and active soil vapor probes is warranted. This study,
which will fill potential soil gas data gaps, should be conducted in the area in direction of groundwater flow (determined as mentioned above).

Please respond to these comments by February 29, 2012, or, alternatively, if you are in agreement with our comments, please submit a work plan to address these issues by March 30, 2012.
Once the risks of soil and groundwater contamination around Building M-585 have been adequately characterized, we can make a close-out determination according to Utah Administrative
Rule R315-101-6. Thank you for your cooperation. If you have any questions, please call Helge Gabert or Jeff Vandel at [phone].

Sincerely,

ORIGINAL DOCUMENT SIGNED BY SCOTT T. ANDERSON ON 2/03/2012

Scott T. Anderson, Director
Division of Solid and Hazardous Waste

STA/HG/tjm

c: Lloyd C. Berentzen, MBA, Health Officer, Bear River Health Department
Nancy Morlock, USEPA Region VIII
Paul Hancock, ATK
Al Lee, ATK

TN201200285 2

195 North 1950 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
TN201200285 Printed on 100% recycled paper

Solid and Hazardous Waste Control Board
Kevin Murray, Chair
Kory Coleman, Vice-Chair
Brian E. Brower
Scott Bruce
Jeff Coombs, MPH, LEHS
R. Ryan Dupont, Ph.D.
Larry A. Ellertson
Brett Mickelson
Brad Mertz
Gary Mossor
Dennis Riding
Dwayne Woolley
Amanda Smith
Scott T. Anderson
Executive Secretary

Department of Environmental Quality

Amanda Smith
Executive Director

DIVISION OF SOLID AND HAZARDOUS WASTE
Scott T. Anderson
Director

State of Utah

GARY HERBERT
Governor

GREG BELL
Lieutenant Governor