History of Agent Orange

A war against an implacable enemy. One who lives among the population. And who hides in the terrain.

Four decades before our involvement in Afghanistan, America had encountered a similar foe in the jungles of Vietnam. It desperately needed some way of countering the enemy’s ability to hide from its guns and bombs while living off the land.

Why Agent Orange?

From 1961 to 1971 (as shown in the Chicago Tribune chart, left), the US government sprayed some 20 million gallons of herbicides and defoliants

over vast areas of South Vietnam (and to a lesser extent in Laos, Cambodia, and even, marginally, North Vietnam), in “Operation Trail Dust.” Some 95% of the herbicides were sprayed by the US Air Force flying C-123s as part of “Operation Ranch Hand.” Fitted with specially developed spray tanks with a capacity of 1000 gallons of herbicide, the planes typically sprayed a 14 kilometer (8.5 mile) swath of land in about 4 ½ minutes. The remaining 5% were sprayed by backpacks, hand, helicopters and trucks around US military installations by the US Army Chemical Corps and allied forces. The herbicides sprayed were up to 50 times the concentration that would have been used for normal agricultural use.

The most common herbicide used was Herbicide Orange, more commonly referred to as “Agent Orange,” a fifty-fifty mixture of the two herbicides 2,4-D and 2,4,5-T. The other most common color-coded chemicals used were Agent Blue, primarily used against food crops, and Agent White.What was the rationale for the program? When President Kennedy came into office in January 1961 the question of what to do in Vietnam was already brewing. By May of 1961 the US objectives in Vietnam were to “prevent communist domination of South Vietnam; to create a viable and increasingly democratic society, and to initiate, on an accelerated basis, a series of mutually supporting actions of a military, political, economic, psychological, and covert character to achieve this objective.”

The US helped South Vietnam to develop the Combat Development and Test Center in order to identify which military tactics and weapons could be used against the guerilla struggle they were facing.  Among the prime competitive advantages of the enemy was their ability to hide in the forest cover while living off the land, so a herbicide powerful enough to deny the North Vietnam Army (NVA) and the anti-government forces in the South (the National Liberation Front or Viet Cong) these assets became very appealing. By July 1961 the idea of using herbicides to better control the border areas had developed to the point of coordinating a defoliation test and the necessary herbicides (Dinoxol) were shipped to South Vietnam. The first testing of the herbicides occurred on August 10, 1961 in Kontom province. Two weeks later a second test run took place along highway 13 north of Saigon.

The defoliation program started out small and nearly ended before it began as the Department of Defense, the State Department and the government of South Vietnam debated its efficacy. However, by November 1961 President Kennedy agreed with his advisors that the US should ‘participate in a selective and carefully controlled joint program of defoliant operations in Vietnam starting with the clearance of key routes and proceed thereafter to food denial only if the most careful basis of resettlement and alternative food supply has been created.” The first official Operation Ranch Hand mission took place on January 13, 1962 along highway 15 using C-123 aircraft.

As the American involvement in Vietnam escalated so did the use of herbicides, Operation Ranch Hand was expanded to include parts of southern and eastern Laos in December 1965.  The herbicide program reached its peak in 1967 when over a million and a half acres were sprayed.

While much of the earlier hesitancy to conduct the herbicide program revolved around concerns of its efficacy, there were also concerns in Washington about how the use of chemical herbicides would be perceived in the world community and how the North Vietnamese government would use the herbicide program as a propaganda tool.  None the less, Secretary of State Dean Rusk assured President Kennedy that the use of herbicides was an acceptable war tactic and did not violate international law. The herbicides were seen by the US government as merely a defoliant akin to those in US domestic use, even if many times the original strength.  Unlike mustard gas, Agent Orange and the other herbicides were targeted against trees and crops, not humans.  The environmental movement had not yet begun; Rachel Carson’s Silent Spring had only been published in 1962 (helping to get the insecticide DDT banned in 1972); and the first Earth Day was years away. It was natural, in the context of the early 1960s, that the use of almost any herbicide would be viewed as fair game in war. Especially as early on in the program it is not likely that the US government knew that dioxin was contaminating the herbicides that contained 2,4,5-T.However, as Operation Ranch Hand expanded it was not only the enemy that was inconvenienced. The Vietnamese peasants whose hearts and minds the US was trying to win tended to take offense at the destruction of their crops and the laying waste of the countryside, as a RAND study would find in 1967.

“If we think they’re winning, you can imagine what they think.”
– President Lyndon Johnson, in a telephone conversation with Senator Mike Mansfield, 1965

The Apparent End

While there was opposition to the herbicide program from the very beginning it did not grow in strength until 1967 when the Federation of American Scientists submitted a petition to the White House with more than 5000 signatures of renowned scientists, including 17 Nobel laureates and 129 members of the National Academy of Sciences to end the herbicide program. Concerns about the ecological impacts of the herbicides in Vietnam were also raised by the American scientific community,  the Association of American Association for the Advancement of Science called for field investigations in Vietnam.

In 1969, it became widely known that the 2,4,5-T component of Agent Orange was contaminated with dioxin, a toxic chemical (chemical structure illustrated above) found to cause adverse health effects and birth outcomes in laboratory studies.  In April 1970, the US government restricted use of 2,4,5-T, and therefore Agent Orange, in both Vietnam and the US.

The last official spray run by the US Air Force took place on January 7, 1971. South Vietnamese forces continued to spray the remaining stocks of Agent Blue and White throughout 1971 and 1972.

In September 1971, the order came to gather all the remaining stocks of Agent Orange, including those under the control of the Armed Forces of South Vietnam. In an operation code-named “Pacer IVY,” the remaining barrels of Agent Orange were re-barreled at Da Nang, Bien Hoa and Tuy Hoa airbases and shipped to Johnston’s Island in the South Pacific. Stocks of Agent Orange in the US were shipped and stored at the Seabees base in Gulfport, Mississippi. Some 8.6 million liters of Agent Orange were destroyed by an incinerator ship in September 1977, in “Operation Pacer Ho.”

While “Operation Ranch Hand” became a footnote in most history books about the war in Vietnam, the on-going impacts of the dioxin that contaminated Agent Orange and some of the other herbicides used during the war continue to this day.

Inside the Barrels: Agent Orange, Blue and White

Video Map of Spraying of Herbicides 1963-70. Developed by Jeanne Stellman.