Defoliants Agent Orange

Several epidemiological studies in Sweden suggested an association between exposure to phenoxyherbicides (and/or their contaminants) and soft tissue sarcomas." There has also been widespread concern among Vietnam veterans that exposure to the defoliant Agent Orange, which contains equal quantities of 2,4-D and... 

The deal soon proved to be less of a bargain than anyone expected. Bliss had decided to mix with his oil some wastes obtained from a chemical plant in nearby Verona, where the defoliant Agent Orange, used during the Vietnam War, was produced. Residents began to wonder about the oil treatment when the treated roads developed an eerie purple sheen and animals in the area began to die. Town officials soon decided to call in the newly created (1970) U.S. Environmental Protection Agency (EPA) to determine the effects (if any) Bliss s oil treatment had had on the community. 

Spraying vegetation during the Vietnam War with the defoliant Agent Orange, a mixture of 2,4-D and 2,4,5-T. This herbicide mixture was contaminated with dioxin. 

Vegetation being sprayed with the defoliant Agent Orange... 

The Seveso disaster began on July 10, 1976 at the Industrie Chimiche Meda Societa Azionaria (ICMESA) chemical plant in Meda, Italy. This event became internationally known as the Seveso disaster, after the name of the most severely affected community. An increase in pressure due to an exothermic reaction in a 2,4,5-trichlorophenol-production reactor caused the rupture disk of the safety valve to burst. About 3000 kg of chemicals were released into the air. The release included 2,4,5-trichlorophenol, used in the manufacture of herbicides, and possibly up to 30 kg of the dioxin TCDD (2,3,7,8-tetrachloro-dibenzo-p-dioxin). Dioxin first came to widespread public notice during the Vietnam War, when it was identified as a component of the defoliant Agent Orange. Dioxin has also been considered to be the most toxic human-made substance. 

Among the best known incidents was exposure of U.S. forces to Agent Orange in Viet Nam. A defoliant. Agent Orange, was contaminated with 2,3,7,8-TCDD. A large number of suits was filed against the manufacturers of these chemicals. These cases have now been settled out-of-court, thus the issue of cause and effect was not addressed. 

Enormous quantities of these two compounds were used in an approximately 1 1 mixture as the defoliant Agent Orange during the Vietnam War. Some samples of 2,4,5-T were shown to be teratogenic (a fetus-deforming agent), and its use has been banned in the United States. 

Dioxin IS carried along when 2 4 5 trichlorophe nol IS converted to 2 4 5 T and enters the environ ment when 2 4 5 T is sprayed on vegetation Typically the amount of dioxin present in 24 5 T is very small Agent Orange a 24 5 T based defoliant used on a large scale in the Vietnam War contained about 2 ppm of dioxin... 

Even so, 2,4-D is advertised as being safe to humans when used as directed, and there is no evidence that the chemical bioaccumulates like DDT does, or that it has any immediate effects on human reproduction or human organs. Although 2,4-D made up nearly half of the active ingredient of Agent Orange, the controversial defoliant used in the Vietnam War, the stated problems with that compound were associated with the contaminant component, dioxin, not... 

Agent Orange A toxic defoliant containing dioxin, of which some 64 million liters were dropped by the U.S. on Vietnam during the war, subsequently causing deformations in babies. 

AGENT ORANGE. Common name for a 50-50% mixture of the herbicides 2.4,5-T and 2,4-D, once widely used by the military as a defoliant. The mixture contains dioxin as a contaminant. See also Dioxin and Herbicides. 

In 1961 the U.S. Army began a highly controversial defoliation and crop destruction program in South Vietnam, in collaboration with the South Vietnamese government, and focussed on areas of major Viet Cong activity. The principle defoliant used was Agent Orange—a mixture of... 

Dioxins are now ubiquitous, thanks to the widespread popularity of 2,4-D and 2,4,5-T herbicides for weed control in agriculture and the massive use of Agent Orange in a defoliation and crop destruction program in Vietnam. Between 1966-81 farm use of herbicides had increased 280)6 to 625M, exceeding total insecticide use. 

Mixtures with other herbicides also are used for weed control. The product Agent Orange, used extensively throughout Vietnam, was about 50% 2,4-D. However, the controversy about the use of Agent Orange was associated with a contaminant (dioxin) in 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) (C8H5Cl303), not with 2,4-D. It should be well understood that 2,4,5-T is different from 2,4-D but similar to 2,4-D as a herbicide component of the defoliant.39... 

Direct human exposure to dioxin occurred in southern Vietnam and also in Seveso, Italy. It was estimated that southern Vietnam has been contaminated by 160 to 600 kg of dioxin as a result of 80 million liters of defoliant herbicides (Agent Orange, a 50 50 mixture of 2,4,5-T and 2,4-D) being sprayed by the US military over a large area of... 

Tetrachlorodibenzo[b,e][l,4]dioxin (TCDD), a contaminant of the defoliant and herbicide Agent Orange Mustard gas, l,l -thiobis[2-chloroethane]... 

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