Longhorn Army Ammunition Plant
Karnack, Harrison County, Texas
Marker Inscription
In 1941, as the United States prepared for eventual entry into World War II, the U.S. Army Ordnance Department approached Monsanto Chemical Company of St. Louis about operating a local plant for production of explosives. Initially called Longhorn Ordnance Works, the plant produced over 400 million pounds of trinitrotolulene (TNT) from 1941 to 1945. After the war, the Army placed the plant on standby status. During the Korean War (1950-1953), the need for munitions rose again, and the Universal Match Corporation, also of St. Louis, managed the site, producing propellant fuel.In 1956, Thiokol Chemical Corporation began manufacturing solid fuel rocket motors here. This highly guarded and classified site grew in a series of five expansions. In 1964, its name changed to the Longhorn Army Ammunition Plant and employment rose to a high of nearly 3,000 personnel. The numbers declined with the end of the Vietnam War and the easing of tensions with the Soviet Union, and employment dropped to less than 1,000 by 1975.In 1987, the United States and the Soviet Union signed the Treaty of Intermediate Nuclear Forces, beginning the elimination of an entire class of missiles. In 1988, the first destruction on American soil of U.S. Pershing I and II rocket motors occurred at the site. Observed by Soviet and U.S. officials, the demolition project continued until 1991. Following official deactiviation in 1995, pollution abatement has steadily provided for adaptive reuse of the former wartime site, now part of the Caddo Lake National Wildlife Refuge. (2007)
Erected by Texas Historical Commission
The Story
When the United States braced for World War II, the Army turned to Monsanto to run a new East Texas plant that poured out more than 400 million pounds of TNT between 1941 and 1945. The site never truly stood down: it made propellant during the Korean War, and from 1956 Thiokol built solid-fuel rocket motors here, employing nearly 3,000 workers by the Vietnam era. Fittingly, in 1988 it became the first place on American soil where U.S. Pershing missiles were destroyed under an arms-reduction treaty with the Soviet Union.
Why it matters
From TNT to rocket motors to Cold War disarmament, the plant is a single site where much of the twentieth century's American arms story—hot war, Cold War, and its unwinding—played out.
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Related events
- · World War II
- · Korean War
- · INF Treaty missile destruction
Themes & tags
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