Scientists boost estimate of Agent Orange sprayed in Vietnam

A study has increased the estimate of how much Agent Orange and other dioxin-tainted defoliants the U.S. military sprayed during the Vietnam War. But it remains unclear whether the increased amount raises the illness risk of those exposed, scientists say.

Re-examining military records, researchers at the Columbia University School of Public Health determined that about 21 million gallons of the herbicides were sprayed from 1961 to 1971 - 1.84 million gallons, or 10 percent, more than previously believed.

About 55 percent of the defoliant was Agent Orange - nicknamed for the color of the identification band on its storage containers. Scientists said the other herbicides, such as Agent Pink, were closely related to Agent Orange but even more potent.

Two-thirds of the herbicides were contaminated with the most dangerous form of dioxin, TCDD, which is associated with cancers, neurological disorders, miscarriages and birth defects.

Details of the study appear in the current issue of the journal Nature.

Agent Orange toxins persist in soil and water in parts of the southern half of Vietnam. Tree cover has re-grown in many locations, but chemicals have migrated into the tissues of fish and fowl that local residents eat.

Studies by U.S. scientists show that blood samples from residents in exposed communities contain dioxin at levels 135 times higher than blood from areas that were not sprayed.

In 1999, Vietnam conducted its own Agent Orange survey, but details were not made public.

``Cancer, miscarriages and birth defects in the sprayed areas are always higher than in the areas not sprayed,'' said Tran Manh Hung of the special committee on Agent Orange in Vietnam's Ministry of Health. ``It might take another 50 years before those rates become equal.''

The Columbia researchers suggest 2.1 million to 4.8 million people were living in 3,181 villages that were directly sprayed.

But other scientists said the work ``does little'' to determine the health consequences of the campaign to deny jungle cover along supply trails used by communist forces.

``What is important from a health perspective is what gets into humans, not what is sprayed,'' said Arnold Schecter of the University of Texas School of Public Health. Schecter has conducted dioxin research in Vietnam since 1984.

``Whether the amount of herbicides is a bit higher and the TCDD content a bit heavier,'' Schecter said, ``what counts for health purposes is the dose the person receives.''

Last year, U.S. and Vietnam conducted their first joint conference on Agent Orange exposure.

In January, the Department of Veterans Affairs extended extra benefits to U.S. veterans suffering from a form of leukemia after researchers found a link to Agent Orange. About 10,000 Vietnam vets receive disability benefits related to the herbicide.

Joseph B. Verrengia, Associated Press

Published April 16, 2003


Exposure to dioxin far worse, says report

Those involved in the Vietnam War, including Australian troops, were exposed to twice the amount of dioxin in Agent Orange than previously thought, according to the journal Nature.

The total amount of the herbicide sprayed was underestimated by between seven and nine million liters, said US researchers who revised US military documents and corrected their errors.

About 10 per cent of the herbicide was used, but the missing inventory contained some of the most dioxin-rich herbicides - dioxin being the toxic active ingredient blamed for diseases and birth defects suffered by millions of Vietnamese and war veterans and their children.

The researchers, from New York's Colombia University and the Institute for Cancer, said the data revealed that "millions of Vietnamese were likely to have been sprayed upon directly" .

Agents Orange, Pink, Green, Purple, White and Blue were sprayed by US planes in Vietnam between 1962 and 1971 to defoliate jungle cover for communist troops, and ruin the crops needed to feed them.

The researchers tracked down US Defense Department documents, including the HERBS file - the flight paths of air force spraying missions between 1965 and 1971.

"The HERBS file error rate was about 10 per cent, attributable largely to transcription, data entry and pilot-recording errors," wrote the researchers.

One of the paper's co-authors, Dr Jeanne Stellman, said: "It's difficult to say who bore the brunt of the increased dioxin.

"The Aussies were in the Rung Sat area, which was the most heavily sprayed area of Vietnam over the course of the war. No-one knows the extent to which presence of dioxin in the soil could have affected troops serving there.

"Hopefully, in a few years (before all the veterans are dead) we will be able to know these overdue answer ... I am certain that Australian researchers will be very interested in our methodology - we've had lots of contact with them."

The HERBS file were first assessed in 1974 by the National Academy of Sciences.

"We have re-estimated the volume and type of herbicides sprayed between 1961 and 1971 to have 7,131,907 more liters than the 'uncorrected' NAS-1974 inventory and 9,440,028 liters more than NAS-1974's 'corrected' inventory, in which about 10 per cent of all missions had been discarded because of obvious recording errors," wrote the researchers.

The national president of the Vietnam Veterans' Association of Australia, Brian McKenzie, questioned whether the original data was wrong by accident or by purpose.

"The whole thing [Agent Orange] has been a series of cover-ups during the war and ever since."

A 1998 Department of Veterans Affairs survey of Vietnam War veterans' health found that among veterans' children:

·         Spina Bifida was 10 times the expected rate.

·         Cleft palates were more than four times higher.

·         Absent body parts 10 times higher.

·         Suicide rates three times the rate of the general population.

·         Cancers, anxiety, psychiatric disorders, accidental death were significantly elevated.

By Stephen Cauchi
April 17 2003