Operation Ranch Hand was a U.S. military operation during theVietnam War, lasting from 1962 until 1971. Largely inspired by the British use of chemicals2,4,5-T and2,4-D (Agent Orange) during theMalayan Emergency in the 1950s, it was part of the overallherbicidal 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 ofSouth Vietnam in an attempt to deprive theViet Cong of food and vegetation cover. Areas of Laos and Cambodia were also sprayed to a lesser extent. According to the Vietnamese government, the chemicals caused 400,000 deaths.[2] The United States government has described these figures as "unreliable".[3]
Nearly 20,000 sorties were flown between 1961 and 1971.[citation needed] The "Ranch Handers" motto was "Only you can prevent a forest"[1] – a take on the popularU.S. Forest Service poster slogan ofSmokey Bear. During the ten years of spraying, over 5 million acres (20,000 km2) of forest and 500,000 acres (2,000 km2) of crops were heavily damaged or destroyed. Around 20% of the forests of South Vietnam were sprayed at least once.[4]
The herbicides were sprayed by theU.S. Air Force flyingC-123s using the call sign "Hades". The planes were fitted with specially developed spray tanks with a capacity of 1,000 U.S. gallons (4 m3) of herbicides. 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).[5] Sorties usually consisted of three to five aircraft flying side by side. 95% of the herbicides and defoliants used in the war were sprayed by the U.S. Air Force as part of Operation Ranch Hand. The remaining 5% were sprayed by the U.S.Chemical Corps, other military branches, and the Republic of Vietnam using hand sprayers, spray trucks, helicopters and boats, primarily around U.S. military installations.[6]
The herbicides used were sprayed at up to 50 times the normal concentration for agricultural use.[citation needed] The most common herbicide used was Herbicide Orange, more commonly referred to asAgent Orange: a fifty-fifty mixture of two herbicides,2,4-D (2,4-dichlorophenoxyacetic acid) and2,4,5-T (2,4,5-trichlorophenoxyacetic acid), manufactured for the U.S. Department of Defense primarily byMonsanto Corporation andDow Chemical. The other most common color-codedRanch Hand herbicides wereAgent Blue (cacodylic acid) that was primarily used against food crops, andAgent White which was often used when Agent Orange was not available.
The Agents used are known as theRainbow Herbicides with their active ingredients, and the periods used were as follows:[7]
The herbicides were procured by the U.S. military fromDow Chemical Company (all but Agent Blue),Monsanto (Agent Orange, Agent Purple, and Agent Pink),Hercules Inc. (Agent Orange and Agent Purple), Thompson-Hayward Chemical Company (Agent Orange and Agent Pink),Diamond Alkali/Shamrock Company (Agent Orange, Agent Blue, Agent Purple, and Agent Pink),United States Rubber Company (Agent Orange), Thompson Chemicals Corporation (Agent Orange and Agent Pink), Agrisect Company (Agent Orange and Agent Purple),Hoffman-Taff Inc. (Agent Orange), and theAnsul Chemical Company (Agent Blue).[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, includingImperial Chemical Industries (ICI).[15]
65% of the herbicides used contained2,4,5-trichlorophenoxyacetic acid that was contaminated with2,3,7,8-tetrachlorodibenzodioxin,[6] a "known human carcinogen... by several different routes of exposure, including oral, dermal, andintraperitoneal".[16] About 12,000,000 U.S. gal (45,000,000 L; 10,000,000 imp gal) ofdioxin-contaminated herbicides were sprayed overSoutheast Asia (mainly in Vietnam, Cambodia, and Laos) during American combat operations in the Vietnam War.[17]
In 2005, a New Zealand government minister was quoted and widely reported as saying that Agent Orange chemicals had been supplied from New Zealand to the United States military during the conflict. Shortly after, the same minister claimed to have been misquoted, although this point was less widely reported. From 1962 to 1987,2,4,5-T herbicide had been manufactured at an Ivon Watkins-Dow plant inNew Plymouth for domestic use, however it has not been proven that the herbicide had been exported for use by the U.S military in Vietnam.[18][19][20][21][22]
For most of the war, Operation Ranch Hand was based atBien Hoa Air Base (1966–1970), for operations in theMekong Delta region where U.S. Navy patrol boats were vulnerable to attack from areas of undergrowth along the water's edge. Storage, mixing, loading, and washing areas and a parking ramp were located just off the base's inside taxiway between the Hot Cargo Ramp and the control tower. For operations along the central coast and theHo Chi Minh trail regions,Ranch Hand operated out ofDa Nang Air Base (1964–1971). Other bases of operation includedPhù Cát Air Base (1968–1970),Tan Son Nhut Air Base (1962–1966),Nha Trang Air Base (1968–69),Phan Rang Air Base (1970–1972), andTuy Hoa Air Base (1971–1972).[23] Other bases were also used as temporary staging areas forRanch Hand. The Da Nang, Bien Hoa and Phu Cat Air bases are still heavily contaminated withdioxin from the herbicides, and have been placed on a priority list for containment and clean-up by the Vietnamese government.
The first aerial spraying of herbicides was a test run conducted on 10 August 1961 in a village north ofĐắk Tô against foliage.[24]: 11 Testing continued into the next year and even though there was doubt in theState Department,the Pentagon and the White House as to the efficacy of the herbicides, Operation Ranch Hand began in early 1962. Individual spray runs had to be approved by PresidentJohn F. Kennedy until November 1962, when Kennedy gave the authority to approve most spray runs to theMilitary Assistance Command, Vietnam and theU.S. Ambassador to South Vietnam.Ranch Hand was given final approval to spray targets in eastern Laos in December 1965.[24]: 45–68
The issue of whether or not to allow crop destruction was under great debate due to its potential of violating theGeneva Protocol.[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 theMalayan Emergency in the 1950s in order to destroy bushes, crops, and trees in an effort to deny communist insurgents the cover they needed to ambush passing convoys.[26] Indeed,Secretary of StateDean 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. Precedent has been established by the British during the emergency in Malaya in their use of aircraft for destroying crops by chemical spraying."[27] The president of South Vietnam,Ngo Dinh Diem, began to push theU.S. Military Advisory Group in Vietnam and theWhite 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.[citation needed] Soon after, crop destruction became an integral part of theRanch Hand program.
Targets for the spray runs were carefully selected to satisfy the strategic and psychological operations goals of the U.S. and South Vietnamese military. Spray runs were surveyed to pinpoint the target area and then placed on a priority list. Due to the low altitude (ideally 150 ft (46 m) required for spraying, the C-123s were escorted by fighter aircraft or helicopter gunships that would strafe or bomb the target area in order to draw out any ground fire if the area was believed to be 'hot'. Spray runs were planned to enable as straight a run as possible to limit the amount of time the planes flew at low altitude. Data on the spray runs, their targets, the herbicide used and amount used, weather conditions and other details were recorded and later put into a database called the Herbicide Reporting System (HERBS) tapes.
The effectiveness of the spraying was influenced by many factors including weather and terrain. Spray runs occurred during the early morning hours before temperatures rose above 85 °F (29 °C) and the winds picked up. Mangroves in the Delta region required only one spraying and did not survive once defoliated, whereas dense forests in the uplands required two or more spray runs. Within two to three weeks of spraying, the leaves would drop from the trees, which would remain bare until the next rainy season. In order to defoliate the lower stories of forest cover, one or more follow-up spray runs were needed. About 10 percent of the trees sprayed died from a single spray run. Multiple spraying resulted in increased mortality for the trees, as did following up the herbicide missions with napalm or bombing strikes.[28]
The use of herbicides in the Vietnam War was controversial from the beginning, particularly for crop destruction. The scientific community began to protest the use of herbicides in Vietnam as early as 1964, when theFederation of American Scientists objected to the use of defoliants.[29] TheAmerican Association for the Advancement of Science (AAAS) issued a resolution in 1966 calling for a field investigation of the herbicide program in Vietnam.[29] In 1967, seventeenNobel laureates and 5,000 other scientists signed a petition asking for the immediate end to the use of herbicides in Vietnam.[29]
In 1970, AAAS sent a team of scientists—the Herbicide Assessment Commission (HAC), consisting of Matthew Meselson,Arthur Westing, John Constable, and Robert Cook—to conduct field tests of the ecological impacts of the herbicide program in Vietnam.[29] A 1969 study by theBionetics Research Laboratory found that 2,4,5-T could cause birth defects and stillbirths in mice. The U.S. government suspended the military use of 2,4,5-T in the U.S. in April 1970.[29] Sporadic crop destruction sorties using Agent Blue and Agent White continued throughout 1970 until the finalRanch Hand run was flown on 7 January 1971.[29]
The use of herbicides as a defoliant had long-termdestructive effects on the people of Vietnam and their land and ecology,[30][31] as well as on thosewho fled in the mass exodus from 1978 to the early 1990s. According to the Vietnamese government, the US program exposed approximately 4.8 million Vietnamese people to Agent Orange, resulting in 400,000 deaths due to a range of cancers and other ailments.[2]
Hindsight corrective studies indicate that previous estimates of Agent Orange exposure were biased by government intervention and under-guessing, such that current estimates for dioxin release are almost double those previously predicted.[32] According to the Vietnamese Government, census data indicates that the United States military directly sprayed upon millions of Vietnamese during strategic Agent Orange use.[32]
According to the Vietnamese government, the program caused three million Vietnamese health problems, with 150,000 children born with severe birth defects,[33] and 24% of the area of Vietnam being defoliated. TheRed Cross of Vietnam estimates that up to one million people were disabled or have health problems as a result of exposure to Agent Orange.[34] The United States government has described these figures as "unreliable".[3] According to the Department of Veteran Affairs, 2.6 million U.S. military personnel were exposed and hundreds of thousands of veterans are eligible for treatment for Agent Orange-related illnesses.[34][35][36]
