Agent Orange is the code name for one of the herbicides and defoliants used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. It was given its name from the color of the orange-striped 55 US gallon (208 litre) barrels in which it was shipped, and was by far the most widely used of the so-called “Rainbow Herbicides”. A 50:50 mixture of 2,4,5-T and 2,4-D, it was manufactured for the U.S. Department of Defense primarily by Monsanto Corporation and Dow Chemical. The 2,4,5-T used to produce Agent Orange was later discovered to be contaminated with 2,3,7,8-tetrachlorodibenzodioxin, an extremely toxic dioxin compound. Vietnam estimates 400,000 people were killed or maimed, and 500,000 children born with birth defects.
During the Vietnam War, between 1962 and 1971, the United States military sprayed nearly 20,000,000 US gallons (75,700,000 l) of chemical herbicides and defoliants in Vietnam, eastern Laos and parts of Cambodia, as part of Operation Ranch Hand. The program’s goal was to defoliate forested and rural land, depriving guerrillas of cover; another goal was to induce forced draft urbanization, destroying the ability of peasants to support themselves in the countryside, and forcing them to flee to the U.S. dominated cities, thus depriving the guerrillas of their rural support base and food supply.
The US began to target food crops in October 1962, primarily using Agent Blue. In 1965, 42 percent of all herbicide spraying was dedicated to food crops. Rural-to-urban migration rates dramatically increased in South Vietnam, as peasants escaped the destruction and famine in the countryside by fleeing to the U.S.-dominated cities. The urban population in South Vietnam nearly tripled: from 2.8 million people in 1958, to 8 million by 1971. The rapid flow of people led to a fast-paced and uncontrolled urbanization; an estimated 1.5 million people were living in Saigon slums.
United States Air Force records show that at least 6,542 spraying missions took place over the course of Operation Ranch Hand. By 1971, 12 percent of the total area of South Vietnam had been sprayed with defoliating chemicals, at an average concentration of 13 times the recommended USDA application rate for domestic use. In South Vietnam alone, an estimated 10 million hectares of agricultural land were ultimately destroyed. In some areas TCDD concentrations in soil and water were hundreds of times greater than the levels considered “safe” by the U.S. Environmental Protection Agency. Overall, more than 20% of South Vietnam’s forests were sprayed at least once over a nine year period.