Operation Ranch Hand
Largely inspired by the British use of chemicals 2,4,5-T and 2,4-D (Agent Orange) during the Malayan Emergency in the 1950s, it was part of the overall herbicidal warfare program during the war called "Operation Trail Dust".
Ranch Hand involved spraying an estimated 19 million U.S. gallons (72,000 m3) of defoliants and herbicides[1] over rural areas of South Vietnam in an attempt to deprive the Viet Cong of food and vegetation cover.
A plane sprayed a swath of land that was 80 m (260 ft) wide and 16 km (9.9 mi) long in about 4½ minutes, at a rate of about 3 U.S. gallons per acre (3 m3/km2).
[8] In April 1967, the entire American domestic production of 2,4,5-T was confiscated by the military; foreign sources were also tapped into, including the Imperial Chemical Industries (ICI).
[15] 65% of the herbicides used contained 2,4,5-trichlorophenoxyacetic acid that was contaminated with 2,3,7,8-tetrachlorodibenzodioxin,[6] a "known human carcinogen... by several different routes of exposure, including oral, dermal, and intraperitoneal".
The Da Nang, Bien Hoa and Phu Cat Air bases are still heavily contaminated with dioxin from the herbicides, and have been placed on a priority list for containment and clean-up by the Vietnamese government.
[24]: 11 Testing continued over the next year and even though there was doubt in the State Department, the Pentagon and the White House as to the efficacy of the herbicides, Operation Ranch Hand began in early 1962.
[25] However, American officials pointed out that the British had previously used 2,4,5-T and 2,4-D (virtually identical to America's use in Vietnam) on a large scale throughout the Malayan Emergency in the 1950s in order to destroy bushes, crops, and trees in effort to deny communist insurgents the cover they needed to ambush passing convoys.
[26] Indeed, Secretary of State Dean Rusk told President Kennedy on 24 November 1961, that "[t]he use of defoliant does not violate any rule of international law concerning the conduct of chemical warfare and is an accepted tactic of war.
"[27] The president of South Vietnam, Ngo Dinh Diem began to push the U.S. Military Advisory Group in Vietnam and the White House to begin crop destruction in September 1961, but it was not until October 1962 when the White House gave approval for limited testing of Agent Blue against crops in an area believed to be controlled by the Viet Cong.
Targets for the spray runs were carefully selected to satisfy the strategic and psychological operations goals of the U.S. and South Vietnamese military.
[29] The American Association for the Advancement of Science (AAAS) issued a resolution in 1966 calling for a field investigation of the herbicide program in Vietnam.
[29] The use of herbicides as a defoliant had long-term destructive effects on the people of Vietnam and their land and ecology,[30][31] as well as on those who fled in the mass exodus from 1978 to the early 1990s.
The Red Cross of Vietnam estimates that up to one million people were disabled or have health problems as a result of exposure to Agent Orange.
