Longhorn Army Ammunition Plant

Environmental Restoration Program

LHAAP-29

Site Description/History

LHAAP-29, also known as the Former TNT Production Area is an 85-acre site located within a heavily wooded section in the western-central portion of LHAAP. Remaining features of former facilities at LHAAP-29 include the foundations for the former production facilities and the underground pipe lines that were originally built for cooling water drainage and TNT wastewater conveyance.

LHAAP-29 was used as a TNT manufacturing facility from October 1942 to August 1945. The facility produced approximately 400 million pounds of flake TNT during its operation using six TNT production lines (five active and one standby). The TNT production facility was inactive from August 1945 to 1959. In 1959, most of the buildings and aboveground storage tanks were removed. The debris was burned or flashed at Burning Ground No. 2 / Flashing Area (LHAAP-17). Concrete foundations, open-top concrete-lined pits, most of the underground utilities, and a network of underground pipelines still remain at the site. Since the end of World War II, the only activity that has been documented to have occurred at LHAAP-29 is the “soak out” or solvent bath of out-of-specification rocket motors. This took place from 1959 to the mid-1970s and involved the use of methylene chloride-based industrial solvent at tank 801-F. Waste from this operation was sent to LHAAP-18/24.

Remediation Activities

Several investigations to determine the nature and extent of contamination in the soil, groundwater, surface water, and sediments at LHAAP-29 were conducted. The Baseline Human Health Risk Aassessment (BHHRA) prepared by Jacobs in 2002 used data from the investigations conducted through 2001, including the plant-wide perchlorate investigation results up to that time. The report concluded that the soil at LHAAP-29 posed a non-carcinogenic hazard and the groundwater posed unacceptable carcinogenic risk and non-carcinogenic hazard to the hypothetical future maintenance worker.

Contaminants of Concern

MC, TCE, 1,2-DCA, 2,4-DNT, 2,6-DNT, 4-NT, 2-NT, 3-NT, arsenic, nickel, and perchlorate in Groundwater.

2,4,6-TNT, 2,4-DNT, and perchlorate in Soil.

Current Phase

In the Remedial Investigation (RI) / Feasibility Study (FS) phase, followed by a Final Record of Decision (ROD).

Future Phase

Future planned phases to complete remedy implementation are Remedial Design (RD) and Remedial Action Construction (RAC).