Operation Ranch Hand, the central component of the US military’s highly controversial herbicidal warfare initiative Operation Trail Dust, occurred in rural parts of South Vietnam during the Vietnam War. The plan was to spray very concentrated herbicides and defoliants over the country’s jungles and mangroves, thus depriving the Viet Cong resistance of both food and cover. The spraying caused horrific environmental damage and pollution, and Operation Ranch Hand is now notorious for its copious use of the chemical Agent Orange, which went on to cause birth defects in children for years to come.
The first test run for the airbound spraying of herbicides took place on 10 August 1961 in a village north of Dak To in the Mekong Delta region, and after about a year of testing, Operation Ranch Hand really started properly in early 1962. It continued for a decade, until a final run on 7 January 1971, by which time the ecological and medical implications of using such dangerous defoliants and herbicides was becoming all too apparent.
Over the course of the campaign, an extraordinary 19 million US gallons of chemicals were sprayed over South Vietnam (and also areas of Laos and Cambodia) in 20,000 missions that attacked 5 million acres of forest and 500,000 acres of food crops. A sortie of around 5 planes—modified C-123s using the rather ominous call sign of “Hades”—flew side by side in formation, each dropping 1,000 US gallons of herbicides over a strip of land around 80 metres wide by 16 kilometres long, all in only four-and-a-half minutes. Because the C-123s had to spray the forests below from a very low altitude, often under 50 metres, they were often accompanied by fighters or bombers that would strafe the target area first.
In a macabre take on the popular US Forestry poster of Smokey Bear alongside the slogan “Only you can protect a forest,” Operation Ranch Hand adopted the environmentally unfriendly motto “Only you can prevent a forest.” They mixed their herbicides at 50 times the concentration used in ordinary agriculture, and mostly used Agent Orange (dichlorophenoxyacetic and trichlorophenoxyacetic acid) and Agent Blue (cacodylic acid), both of which contained human carcinogens.
As early as 1964, US scientists were starting to protest against the use of herbicidal warfare, and in 1967 a consortium of 17 Nobel Laureates and over 5,000 other scientists signed an unsuccessful petition demanding an immediate end to Operation Ranch Hand and other similar actions.
Eventually, after experiments proved that Agent Orange caused stillbirths and birth defects in mice, it was phased out. But the damage was already done, and its disastrous use as a weapon of war is considered one of the most shameful incidents of the Vietnam War.