Longhorn Army Ammunition Plant

Base Background

The U.S. Army acquired the property and established Longhorn Army Ammunition Plant (LHAAP) in December 1941, on an 8,416-acre tract beside Caddo Lake in Karnack, Harrison County, Texas. Production started within the year, and over more than five decades of operation the plant manufactured TNT, pyrotechnics and illuminants, and solid-fuel rocket motors, including motors for the Pershing missile program. The Army deactivated LHAAP in 1997. Roughly 7,000 of the original 8,416 acres now make up the Caddo Lake National Wildlife Refuge, managed by the Fish and Wildlife Service since the transfer, while the Army retains the remaining acreage to continue environmental cleanup under the Base Realignment and Closure program (LHAAP has been a Superfund site since 1990).

Toxic Exposure at Longhorn Army Ammunition Plant

The EPA placed LHAAP on the National Priorities List on August 30, 1990, after decades of explosives manufacturing, rocket-motor production, and waste disposal contaminated the plant’s soil and groundwater with a wide range of substances. The contamination spans former burning grounds, landfills, an evaporation pond, a maintenance/shops complex, and the former TNT production area, and includes explosives-related compounds, perchlorate, chlorinated solvents, and heavy metals. Personnel who worked in these areas, along with civilian employees and contractors on site over the plant’s operating history, could have been exposed.

Explosives and Nitroaromatic Compounds

EPA’s contaminant records for the former TNT production area and nearby burning grounds document 2,4,6-trinitrotoluene (TNT) itself, along with related nitroaromatic byproducts of explosives manufacturing: 2,4-dinitrotoluene, 2,6-dinitrotoluene, 1,3-dinitrobenzene, 1,3,5-trinitrobenzene, nitrobenzene, and 2,4,6-trinitrophenol (picric acid), found in soil, groundwater, and building materials at these sites. Munitions response areas elsewhere on the former plant have also required clearance of unexploded ordnance.

Perchlorate Contamination

Rocket-motor production and disassembly at LHAAP left perchlorate, an oxidizer used in solid rocket propellant, in groundwater, surface water, and soil across numerous areas of the former plant, including the old landfill, several burning grounds, and a munitions test area. The Army operates a groundwater treatment plant that has treated extracted groundwater from several of these areas for years, reducing perchlorate to below applicable cleanup levels before it is released, and long-term monitoring continues.

Volatile Organic Compounds (VOCs)

EPA identifies trichloroethylene (TCE) and methylene chloride as the primary solvents documented in LHAAP’s groundwater, alongside tetrachloroethylene (PCE), vinyl chloride, benzene, carbon tetrachloride, chloroform, and toluene, concentrated around the shops and maintenance complex, several burning grounds, and the old landfill.

Heavy Metals

Soil and groundwater sampling at the burning grounds, the former paint shop, and site landfills confirmed arsenic, lead, chromium, cadmium, mercury, barium, and thallium, among other metals, tied to decades of industrial and waste-disposal activity across the plant.

PFAS Contamination

Longhorn Army Ammunition Plant is one of the Army installations on the Department of Defense’s nationwide list of sites undergoing assessment for per- and polyfluoroalkyl substances (PFAS) use or potential release, tied to firefighting-foam use common across military installations of this era. The plant has completed its preliminary assessment/site inspection as of the DoD’s June 30, 2026 progress report.

Getting Compensation for Toxic Exposure

Nobody working the TNT lines, the perchlorate-soaked propellant areas, or the burning grounds at Longhorn was warned about what they were breathing or handling, and the illnesses that result from such toxins often stay hidden for decades before a diagnosis. Whether it was the veteran who served at LHAAP or a survivor filing in their name now, that kind of diagnosis can still support a VA claim today.

See which illnesses the chart below connects to the substances found at this site. Our VA-accredited lawyers have spent years building toxic exposure cases for veterans and military families, and reviewing your situation costs nothing. Request a free evaluation any time: Hill & Ponton practices VA disability law exclusively and works strictly on contingency, so we don’t get paid unless you do.