Study of Agent Orange's effects in Vietnam canceled

In 2002, Dr. David Carpenter received the first-ever U.S. grant to study Agent Orange's effects in Vietnam, particularly on birth defects, as part of a historic agreement between the two governments.

By 2004, the funding had been rescinded, and the study was canceled.

"I was caught very much right in the middle of a political hot potato," said Carpenter, the director of the Institute of Health and the Environment at the University at Albany.

That study was officially scuttled due to disagreements over details between Vietnam and the United States, but it capped four decades of tension between the nations over the legacy of Agent Orange. The Vietnamese government estimates that 4 million to 5 million Vietnamese were exposed to Agent Orange during the war. Since its end in 1975, according to the Vietnamese government, an estimated 500,000 babies have been born in Vietnam with birth defects.

Agent Orange - the most widely used defoliant during the Vietnam War - contains TCDD, the most toxic chemical known and one of few proven to be carcinogenic. The same chemicals that cause cancer generally also cause birth defects, particularly when the person exposed was the mother. Dioxin compounds such as TCDD are especially dangerous because, once introduced to either an ecosystem or the human body, they are very difficult to get rid of.

According to Carpenter, if the study had linked Agent Orange to birth defects - as he suspects it would have - "the United States would have been liable for reparations for every child in Vietnam with a birth defect."

Though dioxin is more likely to affect a fetus when it is the mother who is exposed, it's possible that the toxin can cause a mutation to the father's sperm, Carpenter said.

Other experts say that, although Agent Orange may have caused many birth defects in Vietnam, it is highly unlikely that it caused every birth defect - since a certain number of abnormalities may occur for various other reasons.

"War itself is hell. People are exposed to all kinds of infectious agents," said Jeanne Stellman, a Columbia University professor who has studied Agent Orange. "Which is not to say that Agent Orange can't cause birth defects, but you have to do a careful study of it if you want to know which ones."