Longhorn Army Ammunition Plant

Environmental Restoration Program

LHAAP-35A (58)

Site Description/History

The LHAAP-35A (58) site, also known as the Shops Area, is located in the north-central portion of LHAAP and currently covers an area of approximately 11 acres. The surface features are a mixture of asphalt-paved roads, a parking area, and areas of wooded and grassy vegetation. The topography is relatively flat with the surface drainage flowing into the tributaries of Goose Prairie Creek.

LHAAP-35A (58) was established in 1942 as part of the installation’s initial construction. The facility was used to provide plant-operated laundry, automotive, woodworking, metalworking, painting, refrigeration, and electrical services. The site was active throughout LHAAP’s mission and became inactive in 1996-1997, along with the entire installation. The LHAAP-35A (58) site boundary has been defined differently in the past. Earlier investigations for LHAAP-35A (58) covered additional areas to the south, however the current site boundary encompasses approximately 11 acres, which also contains sites LHAAP-02, LHAAP-03, LHAAP-60, LHAAP-68 and LHAAP-69.

Remedial Activities

Between 1992 and 2008, multiple investigations were conducted in a phased approach to determine the nature and extent of contamination at the LHAAP-35A (58) site. In 2009, a Feasibility Study (FS) was completed. The findings from these investigations were that the shallow zone groundwater was impacted with volatile organic compounds (VOCs), while the soil and former sump/waste rack sump areas posed no unacceptable threat to human health or the environment. The remedy for this site was implemented in 2013 and included Land Use Control (LUC), Enhanced In-situ Bio-remediation (EISB) in the eastern plume, and monitored natural attenuation (MNA). A contingency remedy for the western plume which included additional EISB injections, was implemented in March and April 2018. The groundwater use restriction LUC boundary encompasses LHAAP-02, LHAAP-03, LHAAP-56, LHAAP-59, LHAAP-60 (Building 714), LHAAP-65, LHAAP-68, and LHAAP-69.

Contaminants of Concern

PCE, 1,1-DCE, TCE, and VC in Groundwater

Current Phase

In the Remedial Action Operation phase including MNA (sampling and reporting), well maintenance, LUC documentation, reporting, and Five-Year Reviews.

Future Phase

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