Agent Orange and other chemicals in the Vietnam War

History of herbicidal warfare

The use of biological and chemical weapons goes back at least 2,500 years. One of the most notable examples of early chemical warfare was the Spartans' use of sulfur in 429 BCE at the Siege of Plataea.

The use of chemicals in war developed over many centuries. Forms of chemical warfare were used in the Middle Ages and the American Civil War. Around the turn of the 20th century, several international treaties banned the use of poisons and chemicals in war. But, this did not stop both sides from using poisonous gases in World War I.

During World War II, Britain and the US investigated using herbicides. Neither nation carried out plans to use the chemicals, but the US developed the defoliant herbicides 2,4,5-T and 2,4-D as part of its biological warfare program.

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Agent Orange herbicide

First made in the 1940s, Agent Orange was used in the US as an industrial farm herbicide and to control weeds along powerlines and railways in forests.

The British Army first used a herbicide very similar to Agent Orange between 1951 and 1953, during the Malayan Emergency. Details of the defoliant CMU 'trioxone' were not released to the public until the 1980s. At that time, New Scientist reported that it was used to thin out jungle vegetation and poison food crops and livestock.

Making and handling CMU 'trioxone' exposed workers and military personnel to dioxin, now known to cause cancers, birth defects and skin conditions. The International Agency for Research on Cancer (IARC) classified dioxin as a known human carcinogen in 1997.

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Testing an effective defoliant

In 1961, South Vietnam asked the US to spray an aerial herbicide against communist guerrilla forces in the country.

US President John F Kennedy did not approve the request straight away. A policy debate considered how the public might see the country's involvement in the military use of herbicides in South Vietnam. Some argued that aerial herbicide spraying was a cost-effective way of targeting Vietnamese communist fighters, by destroying their access to shelter and food. Others were concerned that the US would be criticised and accused of chemical warfare.

In late 1961, Kennedy approved the military use of herbicides in South Vietnam as a limited experiment.

A tactical aerial herbicide spraying program called Operation Ranch Hand began in January 1962. The first major operation was not until September 1962 when US pilots targeted mangrove forests in the Mekong Delta.

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Spraying in South Vietnam

Agent Orange was the most used herbicide in the Vietnam War. Some 61% of herbicides used in the military defoliation program were Agent Orange.

Other herbicide and defoliants were used at different stages of the war, for different purposes. Like Agent Orange, each one had a colour name. The chemical storage drums had a colour strip to match. The so-called 'rainbow herbicides' included, according to a 1994 US report:

• Agent Purple, one of the earliest defoliants used in the war
• Agent Blue, used to kill enemy rice crops
• Agent Pink
• Agent Green
• Agent White.

US planes and helicopters sprayed the chemicals onto the land. Sometimes wind and helicopter blades swept flurries of herbicide back into the planes and onto the crew.

Australian troops were involved in the use of herbicides and insecticides. They sprayed chemicals from trucks and on foot. Insecticides were widely sprayed in Phuoc Tuy province, particularly at Nui Dat, the 1st Australian Task Force (1 ATF) base.

Veterans' advocates, like Graham Walker, said 'significant' amounts of Agent Orange and other chemicals were used in areas where Australian soldiers were based.

Most spraying took place between 1966 and 1969. By late 1969, there was growing public unease about the herbicidal program. Research linked 2,4-D and 2,4,5-T with deformities in animals. By February 1971, the program had ended.

Environmental effects

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Dioxin is a long-lasting toxic chemical found in Agent Orange. It is a known carcinogen, linked with causing cancer in humans.

Some 170 kg of dioxin is believed to have been dumped on land during the Vietnam War, affecting:

• almost 3 million hectares of land
• 18% of Vietnamese forests
• some 20,000 Vietnamese villages.

The wartime herbicidal program had a devastating effect on the Vietnamese environment. Evidence of dioxin is still found in Vietnam's soil, water and food chain.

Pathology samples show dioxin is also found in the Vietnamese population because it is:

• absorbed through the skin
• breathed in via contaminated dust
• consumed via contaminated crops and livestock.

Other environmental impacts include the destruction of forests during the war, leading to a loss of habitat for many animals. Some habitats never recovered.

Dioxin levels in the soil continue to affect regrowth and cause soil erosion, leading to increased flooding incidents.

Impact on Vietnamese people

It's been estimated that 3 million Vietnamese have had health conditions related to herbicide exposure, including:

• cancers
• heart conditions
• infertility and miscarriages
• liver diseases
• neurological conditions.

Media reports have highlighted Vietnamese families' suffering, for example:

• a Pulitzer Centre series
• a documentary on SBS Dateline.

Vietnamese Red Cross Society said many children had been born with deformities and health problems due to wartime chemical exposure. But, research into links between parental exposure to Agent Orange and birth defects in children has been less clear.

A 2006 meta-study, published in the International Journal of Epidemiology, said Vietnamese parents were at greater risk of having children born with abnormalities. But it also highlighted the '... inconsistent findings in the literature'.

The Vietnamese believe Agent Orange is responsible for damaging the health of people who were exposed to it. US veterans can claim compensation for many medical conditions associated with dioxin in Vietnam. But, the US maintains no proof of the link between Agent Orange exposure and health problems. The issue is still debated in courtrooms around the world.

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Impact on veterans

Australians returned from South Vietnam between 1970 and 1973. During the 1970s, veterans' stories were no longer popular with a public that wanted to forget the war.

US veterans faced a similar experience on their return, but the situation began to change towards the end of the 1970s. Articles like one published in 1978 by Rolling Stone magazine highlighted the worrying effects of the herbicide program on veterans' health.

Around the same time, Australian veterans started speaking out about their own health issues and those of their families. There were reports of birth defects in veterans' children, cancer and other health issues. Veterans blamed their exposure to Agent Orange and other chemicals used in South Vietnam.

The Whitlam and Fraser governments denied Australian troops had been exposed to chemical defoliants. Subsequent governments later retracted that position in the face of contrary evidence.

In 1998, an Australian Government study found Vietnam War veterans were more likely to suffer some cancers. The study also found veterans' children had higher rates of birth defects.

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Vietnam Veterans Association of Australia

By the late 1970s, Australian veterans were seeking help for themselves and their families. The repatriation rules administered by the Department of Veterans' Affairs (DVA) would need to change to access government health services and pensions.

There was some resistance to change in both the RSL and DVA. In 1979, the Vietnam Veterans Action Association was formed in response to the resistance. The next year, it became the Vietnam Veterans Association of Australia (VVAA).

The VVAA lobbied hard on behalf of its members. It believed it had a strong case, particularly as more veterans came forward with similar stories. But the VVAA used a lot of anecdotal material rather than clear evidence, and it faced opposition from many politicians and scientists.

In 1982, the VVAA published a list of symptoms associated with exposure to Agent Orange. More veterans came forward to repatriation clinics, recognising at least one or more signs of illness.

Royal Commission

A royal commission was set up in 1983 to examine the evidence linking herbicide exposure to veterans' health problems.

The Australian Government and Monsanto helped fund a legal defence against the VVAA's case. By 1985, the VVAA had run out of money for legal advice. Veteran Phill Thompson spoke on the association's behalf. Phil told the Royal Commission of the 'great imbalance' of resources available to the Vietnam veterans.

Phil claimed 'virtually all' Australian servicemen were exposed to chemicals during their Vietnam service. He also said Vietnam veterans suffered a variety of health issues, including:

• cancers
• heart problems
• immune system ailments
• kidney problems
• liver issues
• loss of libido
• mental health issues.

Phill Thompson was later awarded an Order of Australia medal for his advocacy for Vietnam veterans. He died in 1986. John Schumann, of the Australian band Redgum, wrote a song in Phil's honour, Safe behind the wire.

Commission's findings

On 22 August 1985, the Commission published its final report. The Sydney Morning Herald reported Royal Commissioner Justice Phillip Evatt's findings.

CANBERRA: The Agent Orange Royal Commission has made a clear finding there is no link between chemical defoliants sprayed over Vietnam and the health problems suffered by veterans of the war.

[Sydney Morning Herald, 23 August 1985]

Evatt admitted the existence of health problems but found no link to the use of defoliants in Vietnam. Instead, the Commission blamed 'acute stress'. The report did acknowledge certain chemicals could cause some cancers. It also said a connection to illness in Vietnam veterans was unlikely but 'not fanciful'.

Read Evatt's final report to Cabinet dated July 1985.

Continued efforts for recognition

Controversy surrounded the findings of the Royal Commission. In 1988, the Canberra Times reported claims of false evidence. There were also claims in the final report that chemical company information had been quoted without acknowledgement.

The Royal Commission's findings were disappointing for Vietnam veterans. The VVAA needed a different approach to continue the fight for recognition. The Royal Commission conceded a link between certain cancers, dioxins and insecticides. Using this information, the VVAA appealed individual cases in the courts.

In 1992, US research linked chemical use in Vietnam with cancers and neurological damage. The American National Academies of Sciences examined evidence about the effects of veterans' exposure to chemicals. In 1994, it published its report, Veterans and Agent Orange. This report found 'sufficient' and 'limited evidence' linking herbicide exposure to various cancers and other conditions.

The Keating government acknowledged a link between Agent Orange and cancer in October 1994.

The Australian War Memorial commissioned an independent history of veterans' experiences in 2015. Dr Peter Yule's book, The Long Shadow, was published 5 years later. It describes the post-war health experiences of Vietnam veterans from their own perspectives.