Agent Orange

During the Vietnam War, U.S. forces tried to deny the enemy the concealment provided by forest and jungle cover, by spraying suspected hiding places with defoliants, the most common of which was a mixture called Agent Orange. Defoliants, or chemicals specifically intended to kill plants and not having known effects on humans, are a blurry area under the Chemical Weapons Convention. They are generally not considered chemical weapons, but there are a substantial number of arguments that they should be, especially if they target food crops.

Spraying was principally done from modified C-123 Provider light transport aircraft, without extensive chemical protection for the crews. The program was called Operation RANCH HAND.

In this case, the defoliants, the most common of which was called Agent Orange, was itself was considered nontoxic to humans and not targeted at food crops. It was primarily composed of commercial herbicides known as 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). Many batches, however, had an exceptionally toxic byproduct of the manufacturing process, 2,3,7,8-tetrachlorodibenzo-p-dioxin (which can also be abbreviated as 2,3,7,8-TCDD), caused significant contamination, and long-term health consequences, including defects, on both Vietnamese and Americans. This was also used by Canadian Forces in Canada, who documented the later-understood health effects.

2,3,7,8-TCDD is listed as a hazardous chemical by the Environmental Protection Agency. Specificically, it is a presumed carcinogen.

The United States Department of Veterans Affairs (DVA) considers the presence of certain diseases, as well as birth defects in their children, in Vietnam War veterans as presumptively due to Agent Orange exposure. As such, the DVA takes responsibility for medical care by the United States Veterans Health Administration and for disability payments.