DSHW-2003-008312 - 0901a06880160311

July 25, 2003

Paul Hancock
Manager, Environmental RemediationATK – Thiokol Propulsion, PromontoryP.O. Box 707Brigham City, Utah 84302-0707
Subject: Hazardous Waste Management Units (HWMU) M114 and M508Dear Mr. Hancock:This letter approves the closure plans and reports and verifies closure certification for the above
referenced HWMUs.  This approval and verification means that the stipulations of the consent order that required closure of these sites have been satisfied.  Silver was detected (776
mg/kg) in subsurface soils at HWMU M508 above EPA residential risk-based values (390 mg/kg); however, the silver concentrations are below EPA industrial risk values (5100 mg/kg). This
indicates a need for tracking soil excavations at this site and placing a notice with the land deed, title and other appropriate documents.  The tracking is needed to ensure that excavated
soils are not used in a residential or other inappropriate setting. The land notice must acknowledge that subsurface soil and shallow groundwater are contaminated. The Division is currently
in the process of preparing the Thiokol post-closure permit for reissuance. The permit will be updated to include requirements for tracking of excavated soil for HWMU M508.  With the
exception of contaminated groundwater, use of the HWMU M114 site is unrestricted.Because hexavalent chromium, volatile organic (VOC) and perchlorate contamination have been detected
in groundwater in the HWMU M508 wells and other wells in the area, post-closure groundwater monitoring is required. HWMU M508 is the source of the hexavalent chromium, solid waste management
unit (SWMU) 503 and a recently identified abandoned drainfield located near well M508-1 are considered sources of the VOC contamination and a perchlorate source has not been identified.
When the post-closure permit is re-issued, it will include provisions for a groundwater investigation and groundwater monitoring. Thiokol is requested to provide a schedule for submittal
of a post-closure groundwater investigation and monitoring plan for HWMU M508 within 30 days of receipt of this letter. An outline of a subsurface conceptual model and data quality
objectives (DQO) for groundwater at this site should be included as justification for the dates in the schedule. The schedule and other information will be included in the post-closure
permit.
The source of the low level VOC and perchlorate contamination detected in the single well at HWMU M114 has not been identified.  However, based on the site history provided by Thiokol,
HWMU M114 is not believed to be the source of this contamination.  As previously requested informally by Division staff, Thiokol should submit a plan to address groundwater flow conditions
in the eastern area of the Thiokol property and the location of the source of groundwater contamination at HWMU M114 and other sites in the area. A schedule for submittal of this plan
and an outline of the subsurface conceptual model and DQOs that will be included in the plan should be provided for approval within 30 calendar days of receipt of this letter. This
outline and schedule will be included in the re-issued post-closure permit.If you have any questions, please contact Jeff Vandel or Dave Larsen of my staff at [phone].Sincerely,Original
Document Signed by Dennis R. Downs on 7/25/03Dennis R. Downs, Executive SecretaryUtah Solid and Hazardous Waste Control Board
DRD/DCL/kk
c:   Mary Wu, USEPA Region VIII
    John C. Bailey, M.D., M.S.P.H., Health Officer/Director Bear River Health Dept.

TN200301622.doc
July 25, 2003
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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