Agent Orange

Did You Know?

• TCDD binds to the cytoplasmic aryl hydrocarbon receptor (AhR), a transcription factor that influences gene expression after translocating to the cell nucleus.
• Arthur Galston, who discovered the defoliants later used in Agent Orange, was contracted by the U.S. Department of the Army in 1943 to study the effects of 2,4-D and 2,4,5-T on cereal grains and broadleaf crops.

Use in the Vietnam War

The Republic of Vietnam Air Force conducted herbicide operations with American help that August. The U.S. military sprayed nearly 20,000,000 of various chemicals—the rainbow herbicides—in Vietnam, eastern Laos, and parts of Cambodia between 1962 and 1971, with peak activity from 1967 to 1969. The goal was to defoliate rural and forested land, depriving guerrillas of food and concealment, and to clear areas around base perimeters and roads. Samuel P. Huntington argued the program also aimed to force peasants to flee to U.S.-dominated cities, depriving guerrillas of rural support. Agent Orange was usually sprayed from helicopters or low-flying C-123 Provider aircraft fitted with sprayers and MC-1 Hourglass pump systems, as well as from trucks, boats, and backpack sprayers.

Health effects

Cancers associated with Agent Orange include chronic B-cell leukemia, Hodgkin's lymphoma, multiple myeloma, non-Hodgkin lymphoma, prostate cancer, respiratory cancer, lung cancer, and soft tissue sarcomas, though some literature claims neither Agent Orange nor its contaminants are carcinogenic in humans. The Vietnamese government states 4 million citizens were exposed and up to 3 million have suffered illnesses, including their children; the Red Cross of Vietnam estimates up to 1 million people are disabled or have health problems due to contamination. The U.S. government has challenged these figures as unreliable. A study by Dr. Nguyen Viet Nhan found children in sprayed areas have multiple health problems including cleft palate, mental disabilities, hernias, and extra fingers and toes. In the 1970s, high dioxin levels were found in breast milk of South Vietnamese women and in blood of U.S. military personnel. A 2006 meta-analysis by Anh Duc Ngo and colleagues found heterogeneity between studies, with Vietnamese-funded studies showing a relative risk of birth defects around 3, while studies from the rest of the world showed 1.29. Data near statistical significance suggests Agent Orange contributes to stillbirths, cleft palate, and neural tube defects, with spina bifida being the most statistically significant defect.

Legal and diplomatic proceedings

The environmental damage from Agent Orange prompted the United Nations to pass Resolution 31/72 and ratify the Environmental Modification Convention, though many states do not regard this as a complete ban on herbicides in warfare. Article 2(4) of Protocol III of the Convention on Certain Conventional Weapons contains a Jungle Exception that prohibits attacks on forests except when used to conceal combatants or military objectives, which has been argued to cover situations like U.S. tactics in Vietnam. Since at least 1978, lawsuits have been filed against producers including Dow Chemical, Monsanto, and Diamond Shamrock. In 1978, army veteran Paul Reutershan sued Dow Chemical for $10 million after being diagnosed with terminal cancer he believed resulted from Agent Orange exposure. After his death in December 1978, his attorneys added plaintiffs and refiled as a class action representing thousands of veterans. Attorney Hy Mayerson worked with environmental attorney Victor Yannacone in 1980 on the first class-action suits. The corporate defendants sought to escape culpability by blaming the U.S. government.

Use outside of Vietnam

In 2008, Australian researcher Jean Williams claimed cancer rates in Innisfail, Queensland, were 10 times higher than the state average due to secret testing of Agent Orange by Australian military scientists during the Vietnam War. Former soldier Ted Bosworth backed the claims, but neither produced verifiable evidence. The Queensland health department determined cancer rates in Innisfail were no higher than elsewhere. The U.S. military, with Canadian government permission, tested herbicides including Agent Orange near Canadian Forces Base Gagetown in New Brunswick. In 2007, Canada offered a one-time ex gratia payment of $20,000 for exposure at CFB Gagetown. A class action lawsuit filed in 2005 on behalf of over 1,100 Canadian veterans and civilians was rejected by the Federal Court of Canada in 2009 citing lack of evidence. In 2007, the Canadian government announced the base was safe. A 2024 legislative commission in Maine found the Canadian investigation incorrect, biased, and based on incomplete data and poor study design. In February 2011, the Toronto Star revealed Agent Orange had been used to clear Crown land in Northern Ontario, with forestry workers acting as human markers holding red balloons while planes sprayed herbicides. The Ontario provincial government launched a probe in response.