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The U.S.

Agent Orange-Dioxin contaminated not only areas of South Vietnam, but also where the chemical was manufactured, stored, tested or disposed of, in the U.S. and elsewhere in the world.

The chemical components of Agent Orange, the phenoxy herbicides, 2,4,5-T and 2,4-D, were made by 37 U.S. chemical companies, beginning in the late 1940s. Prior to and during the Vietnam War, these herbicides were used in industrial agriculture domestically. They were also sprayed along railroads and power lines, and more, to control undergrowth in U.S. American forests.

For the war effort, the U.S. military procured over 20 million gallons of Agent Orange, roughly a fifty-fifty mixture of 2,4-D and Dioxin-contaminated 2,4,5-T, from nine chemical companies:​

  • Dow Chemical Company, in Midland, MI

  • Monsanto Company, in Nitro, WV

  • Diamond Shamrock Corporation, in Newark, NJ

  • Hercules Inc., in Jacksonville, AR

  • Thompson Hayward Chemical Co., in Kansas City, KS

  • United States Rubber Company (Uniroyal), in Elmira, Ontario

  • Thompson Chemical Co., in St Louis, MO

  • Hoffman-Taff Chemicals, Inc., in Verona, MO

  • Agrisect


Many of these former manufacturing sites, where Dioxin-contaminated 2,4,5-T was manufactured, are now EPA-designated Superfund sites and in various stages of containment, clean-up and remediation. For decades now, local communities near these sites have been battling the chemical companies, the EPA and the U.S. Army Corps of Engineers over the issue of Dioxin contamination.



As early as 1943, the U.S. military, together with the University of Chicago, began studying various chemicals and their application to be used for vegetation control. Then in early 1945, the result of their research efforts, incipient mixtures of 2,4-D and 2,4,5-T, were first tested by the U.S. military in Florida at the Bushnell Army Airfield, against the tropical foliage and crops there, and additionally elsewhere over the years, in California, Indiana, Kentucky, Montana, North Dakota, New York and more.

Tactical herbicide formulations and spray equipment were developed consequently, by the U.S. Department of the Army Chemical Corps at Fort Detrick, MD, in anticipation of the intensifying war on the Korean peninsula. 

Then by the early 1960s, developed formulations of 2,4,5-T and 2,4-D were being tested across the U.S. and around the world, in India, Thailand and Canada, among other countries. 2,4,5-T and 2,4-D were used for defoliation, while other organic arsenicals were used for crop destruction. Spray equipment had also been adapted to enable aerial spraying at controlled rates and concentrations.

Information about where herbicides were used, stored and tested is still incomplete. What is known is that herbicides were shipped to Vietnam from several U.S. ports, including Baltimore, Seattle and New Orleans, early on in the war; and from Mobile, Alabama and Outport of Gulfport, Mississippi, after 1966.

The VA has updated a list of these locations and more on their website in 2019. But while this updated list includes some new locations, it has left out sites that were on an earlier version

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