Columbia University

The war in Vietnam extended into Cambodia and Laos.
Agent Orange came with it.

While almost all of the 20 million gallons of herbicides used during the War were sprayed in southern Vietnam, Cambodia and Laos were also sprayed.  However, very little is known about the present day impacts on the people or the environment of these two countries. The War Legacies Project is currently conducting a survey to determine the extent of the environmental and human health impacts of Agent Orange/Dioxin in southern Laos.


Flight records show that there were spray missions flown in Laos on 209 dates between 1965 and 1970, with a total of at least 537,495 gallons sprayed. The heaviest spraying was in the first half of 1966 and continued at a steady rate until February 1967, after which spraying was intermittent until its end in October 1970. Most of the spray runs were coordinated out of Bien Hoa airbase as part of the Ranch Hand Operation, with some also run out of Ton San Nhat and Da Nang.  

There are not many records detailing the spray locations, though according to the limited data, the areas most frequently sprayed were in Savannakhet, Salavan and Attapeu provinces along where the Ho Chi Minh Trail (National Geographic Society map, right) entered Laos from the DMZ area of Vietnam.  Unfortunately, very little is known about spraying that was done by hand or helicopter and whether or not the CIA conducted any spraying in Laos. 

As in Vietnam, Agent Orange was sprayed not only to defoliate the countryside, but also to destroy crops. Records from Military Assistance Command Vietnam (MACV) show that 64 crop destruction missions took place between September 1966 and September 1969, over a total of 20,485 acres. 

According to William Buckingham’s history of Operation Ranch Hand, up until September 1969, the US Air Force sprayed 419,850 gallons over 163,066 acres of Laos. However, it is not certain if some of these acres were sprayed more than once.  75% of the herbicides sprayed were Agent Orange, followed by Agent Blue (15%) and White (10%).

Like the bombing of Laos during the war, the use of herbicides in Laos was kept “secret.” It was not revealed until 1982, when Buckingham’s draft of “Operation Ranch Hand Study” was made public in response to the Freedom of Information Act.


Unlike Laos, Cambodia was not systematically sprayed.  There was likely some mist drift into Cambodia as areas close to the border in Vietnam were sprayed.  The one recorded direct spraying of herbicides in Cambodia took place from April 18–May 2, 1969, when 173,000 acres of French and Cambodian rubber plantations in Kampong Cham Province in Cambodia were sprayed. 24,000 of these acres were seriously damaged.   The spraying took place at night and it was unclear who carried out the spraying, but it was not believed to be by the US Air Force.  Evidence points to CIA and Air America aircraft. In 1969, the Cambodian government filed a claim for $12.2 million in damages.  Though the US never admitted they were responsible, they made plans to pay the claim to promote “broader interests.”  Henry Kissinger, at the time the National Security Advisor, attempted to delay paying the claim until FY1972, writing “Every effort should be made to avoid the necessity for a special budgetary request to provide funds to pay this claim.”

Anecdotal reports from residents of Mondulkiri and Ratanakiri Provinces in Northeast Cambodia point to the possiblity that herbicides were sprayed in these regions as well during the war. More research is needed to confirm these reports.

Philip Jones Griffiths

14 years old, Phnom Penh, 2002.

Agent Orange in the Viet Nam War: History and Consquences

by Prof. Dr. Le Cao Dai
(published in Vietnam - not currently available)