Agent Orange (Salem Health: Cancer)
Exposure routes: Inhalation, ingestion, skin contact, ocular absorption
Where found: Herbicide mixtures formerly used for agricultural, forestry, and military purposes
At risk: Combatants and civilians exposed to Agent Orange during the Vietnam War and their children, workers occupationally exposed to the chemical, and populations exposed through domestic herbicide spraying
Etiology and symptoms of associated cancers: Because epidemiologic data on Vietnam veterans is limited, the health effects of Agent Orange have been studied indirectly in certain populations highly exposed to dioxin or dioxin-tainted herbicides. These studies provide sufficient evidence linking Agent Orange to chloracne, an acnelike skin disorder, and to certain cancers, induced when TCDD activates a protein receptor in target cells. The soft-tissue sarcomas develop from fat, muscle, or deep body tissues and usually appear as a lump. Hodgkin disease (highly curable) and non-Hodgkin lymphoma originate in lymphatic tissue and result in painless swelling of lymph nodes under the skin. Chronic lymphocytic leukemia, which develops from white blood cells, is often asymptomatic, but later is marked by enlarged lymph nodes. Paternal exposure to Agent Orange has been associated with acute myelogenous leukemia in children. This fast-growing cancer of the bone marrow produces abnormal white blood...
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Agent Orange (Encyclopedia of Environmental Issues, Revised Edition)
Between 1962 and 1971, some 19 million gallons of herbicides were sprayed by the U.S. military over South Vietnam and Laos by airplane, helicopter, boat, truck, and manual sprayers in an effort to reduce ground cover for enemy troops and to destroy enemy crops. About 11 million gallons of this total was sprayed in the form of Agent Orange, a fifty-fifty mixture of the herbicides 2,4-D and 2,4,5-T combined with a kerosene-diesel fuel for dispersal. The principal components of both 2,4-D and 2,4,5-T decompose within weeks after application; however, 2,4,5-T contains between 0.05 and 50 parts per million of dioxin, primarily 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD), which is among the deadliest chemicals known and which has a half-life of decades. Approximately 368 pounds of dioxin were released during the spraying, with profound effects on both the ecology of the region and the subsequent health of U.S. military personnel, the residents of Vietnam and Laos, and their offspring.
Agent Orange constituted about 60 percent of total volume of herbicides sprayed by U.S. personnel in the region; other substances used included dinoxol, trinoxol, bromacil, diquat, tandex, monuran, diuron, and dalapon as well as compounds known by such code names as Agent White, Agent Blue, Agent Purple, Agent Green, Agent Pink, and Agent Orange II (“Super Orange”). In addition to 2,4-D and 2,4,5-T, various mixes included picloram (a growth regulator similar...
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Military Background (Encyclopedia of Environmental Issues, Revised Edition)
The U.S. military developed weapon herbicides during World War II at Fort Detrick in Frederick, Maryland, and considered using them against Japanese food plots on Pacific islands. The British used herbicides in Malaya in the 1950’s to destroy rebel food plots. Domestic tests of Agent Orange were conducted at Camp Drum, New York, and Eglin Air Force Base, Florida, in the 1950’s. The first field tests were conducted in South Vietnam in 1961 and in Thailand in 1964 and 1965.
“Operation Ranch Hand” was the code name given to the U.S. Air Force program of herbicide application during the Vietnam War. The program involved a total of thirty-six aircraft that sprayed roughly 10 percent of the area of South Vietnam. The spraying and defoliation targeted jungles, inland forests, camp edges, roads, trails, railroads, and canals to make enemy movement conspicuous and easier to attack. Because of the possible risk to the crops of the United States’ South Vietnamese allies, spraying of enemy food plots was not as extensive. In addition, the Army Chemical Corps conducted truck, helicopter, and manual spraying (particularly around base camps and transportation routes); the U.S. Navy, using small riverboats, sprayed edges of rivers and canals; and Special Forces troops conducted covert spraying operations.
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Environmental Damage in Vietnam (Encyclopedia of Environmental Issues, Revised Edition)
Many of the trees in the tropical mangrove forests near the southernmost coasts of South Vietnam were killed by a single spraying. It is estimated that it will take up to a century for the mangrove forests to recover without reseeding. Since these and adjacent waters served as breeding and nursery grounds for wildlife, the area’s ecology was catastrophically affected.
Inland forests were less sensitive to Agent Orange. They usually recovered after single or double sprayings with only temporary foliage loss. However, three or more sprayings eventually induced tree death and converted forests to grasslands. Wildfires burned seeds and seedlings of native trees, further delaying recovery. Erosion washed sediment into deltas near river outlets, compounding environmental damage. Since approximately one-third of sprayed land was sprayed more than once, and 52,600 hectares (130,000 acres) were sprayed more than four times, damage to Vietnam’s ecology was extensive.
Elevated concentrations of toxins have continued to affect Vietnam’s population and environment. Because of the persistent effects of dioxin, which is fat-soluble and bioaccumulates up the food chain, health problems related to the spraying have affected not only Vietnamese alive during the war but also their offspring. Malformations and birth defects are common in Vietnamese children, and other maladies are suspected to be linked to dioxin...
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Health Effects in American Vietnam Veterans (Encyclopedia of Environmental Issues, Revised Edition)
Agent Orange and dioxin are now known to have caused comparable health problems in American veterans of the Vietnam War. Health problems linked to exposure include the cancers soft-tissue sarcoma, non-Hodgkin’s lymphoma, and Hodgkin’s disease and the skin diseases chloracne and porphyria cutanea tarda. There is a definite correlation between Agent Orange exposure and respiratory cancer, prostate cancer, multiple myeloma, acute and subacute peripheral neuropathy, and spina bifida (abnormal spine development in children of veterans). Other suspected health effects include immune system disorders, reproductive difficulties and cancers, diabetes, endocrine and hormone imbalances, cancer in offspring, and malformations and defects (there is much stronger evidence linking birth defects to dioxin in Vietnamese). It appears that many of these health problems (including spina bifida, birth defects, immune system problems, and cancer propensity) can be passed on to the children and even the grandchildren of those initially exposed.
These issues were controversial for years after the war, but as evidence accumulated, the Department of Veterans Affairs (VA) eventually addressed the issue. Free medical examinations and care were offered to Vietnam veterans with suspected Agent Orange-induced problems in 1978. By 1981, the VA had established a program providing follow-up hospital care to veterans with any...
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Further Reading (Encyclopedia of Environmental Issues, Revised Edition)
Buckingham, William A., Jr. Operation Ranch Hand: The Air Force and Herbicides in Southeast Asia, 1961-1971. Washington, D.C.: Office of Air Force History, U.S. Air Force, 1982.
Griffiths, Philip Jones. Agent Orange: Collateral Damage in Vietnam. London: Trolley, 2004.
Institute of Medicine. Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam—Update 2008. Washington, D.C.: National Academy Press, 2009.
Young, Alvin Lee. The History, Use, Disposition, and Environmental Fate of Agent Orange. New York: Springer, 2009.
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Agent Orange (Encyclopedia of Science)
Agent Orange is one of several herbicidal (plant-killing) preparations that was used by the U.S. military to destroy forests and enemy crops in Vietnam in the 1960s. Agent Orange was created by mixing equal quantities of two agricultural herbicides commonly used to kill weeds: 2,4-D and 2,4,5-T. Present in the 2,4,5-T as an impurity was 2,3,7,8-tetrachlorodibenzo-p-dioxin (usually abbreviated to TCDD), a dioxin contaminant that is highly toxic to some animals. (Dioxin is a term used collectively for a group of chemical by-products of papermaking and other manufacturing processes.)
During the Vietnam War (19615; a civil war between the communist North and the democracy-seeking South), North Vietnamese guerrillas found cover in the lush jungles of South Vietnam. To deprive their opponents of hiding places and food crops, the U.S. military instituted a program called Operation Ranch Hand, which involved the aerial spraying of herbicides. Ground spraying from boats, trucks, and backpacks occurred as well. In all, U.S. troops sprayed approximately 19 million gallons (72 million liters) of Agent Orange and other herbicides over 4 million acres (1.6 million hectares). This military strategy is thought to have saved the lives of many U.S. combat soldiers who had been sent to fight on behalf of the South Vietnamese.
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