US abandons health study on Agent Orange

Cultural divide condemns Vietnam project.

A programme to investigate the health and environmental damage caused by widespread use of the defoliant Agent Orange during the Vietnam War has been cancelled before it even began.

Scientists say that the collapse of the project is largely the result of cultural differences, a lack of communication, and a deep reservoir of suspicion between the Vietnamese and US governments.

The United States used Agent Orange to reduce forest cover during the Vietnam War. But since the war's end in 1975, Vietnam has suffered a high number of birth defects — estimated to be 2–3 times the expected number in some areas — which it blames on the defoliant.

The herbicides that made up Agent Orange were contaminated with dioxins, a highly toxic group of chemicals. But a lack of reliable epidemiological studies means that there is uncertainty over the suspected link between dioxins and birth defects. Such studies are difficult to do in part because a single test for dioxins costs US$1,400.

Vietnam blames many of its birth defects on Agent Orange. Credit: HOANG DINH NAM/AFP/GETTY IMAGES

The joint US–Vietnamese research project would have analysed dioxin levels in 300 mothers of babies with birth defects, along with 300 mothers of healthy children. The study was approved in May 2003 by the US National Institute of Environmental Health Sciences (NIEHS) based in Research Triangle Park, North Carolina. But the institute pulled the plug on the project last month because, after two years, the Vietnamese Ministry of Health had still not approved the research protocols needed to begin the work.

David Carpenter, the study's principal investigator and an environmental health researcher at the University at Albany in New York, says that the project fell victim to politics with “two different cultures coming together and not communicating well”. This led to misunderstandings from the outset, he says. Before funds of $1 million a year for the three-year project were freed up, the NIEHS provided $300,000 for a pilot study to verify that dioxin levels would be detectable in Vietnamese women. Although done for valid scientific reasons, this was not fully explained to Vietnamese officials, who viewed it as a snub, says Carpenter.

“The NIEHS was probably insisting on protocols to ensure a real, valid study; the implications of which the Vietnamese either didn't understand when they agreed, or else simply don't want,” says Jeanne Mager Stellman, a scientist at Columbia University in New York, whose research has provided maps of herbicide spraying in Vietnam (see Nature 422, 649; 2003 ).

Anne Sassaman, a director at the NIEHS, defends the decision to cancel the project, saying that progress has been minimal despite repeated visits by NIEHS officials to Vietnam and the agency playing host to three Vietnamese delegations. A general agreement to conduct joint research between the countries (see Nature 416, 252; 2002 ) is still in place, she adds, and the NIEHS “remains hopeful that other studies on Agent Orange can be conducted in the future; we would be very happy to support them”.

But researchers close to the programme say that the Agent Orange study was viewed by the NIEHS as a test case, and in the wake of its failure the agency is likely to be reluctant to entertain new proposals. “I'm not optimistic about what's next,” says Carpenter.

The study was expected to provide evidence for a class action suit on behalf of millions of Vietnamese plaintiffs against US manufacturers of Agent Orange. This case was dismissed by a US judge on 10 March on the grounds that use of the defoliant in Vietnam could not be considered a war crime.


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Butler, D. US abandons health study on Agent Orange. Nature 434, 687 (2005).

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