Longhorn Army Ammunition Plant

The Longhorn Army Ammunition Plant is a 8493 acre government-owned, contractor-operated (GOCO) facility in Karnack, Texas that was established in 1942. The Monsanto Chemical Company selected the site in December 1941 to produce TNT. The plant produced 393,000,000 pounds of TNT throughout World War II. After the signing of the Intermediate-Range Nuclear Forces Treaty on December 8, 1987, the Longhorn plant was used to destroy Pershing IA and II missiles. The plant was operated by Thiokol.

Environment
The Longhorn Army Ammunition Plant was listed as a Superfund site on the National Priorities List on August 30, 1990. The United States Environmental Protection Agency listed the primary contaminants of concern as solvents used at the site. Methylene chloride and trichloroethene were detected in the groundwater on the plant, but were only detected in limited amounts in streams flowing into Caddo Lake. The groundwater, surface water, and soil on the plant have been found to be contaminated with perchlorate. Sediment samples from streams near Caddo Lake found elevated levels of lead and mercury. Clean up activities began on October 25, 1996 and continue to this day.