Under Operation Ranch Hand, the U.S. Air Force flew more than 6,000 spraying missions of Agent Orange on the forests of South Vietnam, Cambodia, and Laos between 1962 and 1971 making it part of the never-ending legacy of the Vietnam War. It is estimated that between 18 and 20 million gallons of herbicide were dumped on various targets.
Background
In 1961, when U.S. involvement in Vietnam was still limited to “advisory staff,” South Vietnamese President Ngo Dinh Diem asked the U.S. to conduct a series of aerial herbicide sprayings to defoliate parts of the vast jungle where Vietcong strongholds were known to exist.
This request sparked a heated debate in Washington. On one side were those who believed herbicides to be "economical and efficient" in eliminating the hiding and ambush locations, and tainting the food supplies. Opposing voices declared that negative propaganda charging the U.S. with chemical warfare, as well as alienating the "friendlies," was not worth the risk.
By November of 1961, a compromise was reached, which allowed limited spraying on a mission-by-mission basis, and that the operation was to involve the South Vietnamese military.
Spraying began in January 1962 under the code name “Operation Hades.” The code name, however, was seen as “PR-unfriendly” and was changed shortly thereafter to “Operation Ranch Hand.”
The rainbow chemicals
Agent Orange was first developed at the University of Chicago during World War II. Professor E.J. Kraus identified a way to control the growth of plants by injecting them with hormones. Broadleaf vegetation was especially susceptible to sudden, rapid growth, which caused plant death.
Although it was the most widely used chemical in the war, Agent Orange was not the only herbicide available for the defoliation effort. As the name connotes, the rainbow chemicals included Agents White, Blue, Purple, Pink, Green, and “Super Orange.” The color code was derived from the stripes on individual 55-gallon drums of each herbicide. In all, 15 different herbicides were tested.
Chemical composition
Kraus contacted Army scientists in the War Department when he found that heavy doses of 2,4-D¹ could be used to kill some forms of vegetation and might be of use in the war effort. The end of the war arrived before the scientists could confirm the claim.
The hormone theory was picked up by civilian scientists, and they developed a marketable product for controlling weeds along railroad rights of way and roadsides, as well as in private lawns.
The Army renewed their efforts to build on what they knew and found that combining 2,4-D with 2,4,5-T² made a deadly cocktail for the foliage. Unfortunately, what the scientists didn’t know (or covered up) was that 2,4,5-T contained dioxin, a useless but deadly by-product of herbicide production. It was discovered to produce skin diseases and liver damage in both the Vietnamese population and U.S. veterans exposed to it.
Other combinations were found that were of varying effectiveness. Agent White was the second-most used herbicide in the spraying campaign. It contained, among other things, picloram, which may cause damage to the central nervous system, weakness, diarrhea, weight loss, and in the long term, liver damage. Agent Blue contained cacodylic acid, better known as arsenic.
Agent Orange and the rest of the herbicides were primarily delivered to their targets by the 309th Air Commando Squadron of C-123 “Providers” from Tan Son Nhut Air Base. The airplanes were rigged with spraying equipment that spread 1,000 gallons of herbicide in just a few minutes.
Anecdote
The "Green Room," or the briefing/debriefing room/lounge sported a sign above the door that read “Remember, Only YOU Can Prevent Forests.”