Agent Orange and Dioxin Chronology; Past, Present and Future

From approximately 1962-1971, Agent Orange, a phenoxyherbicide contaminated with 2,3,78-TCDD, the most toxic dioxin, was sprayed in certain specific areas in southern Vietnam primarily to defoliate jungles where troops opposing the South Vietnam and the U.S. governments could find shelter and to destroy food meant for these troops and their civilian supporters.

TCDD was first measured in humans, in breast milk of nursing mothers in an area in the south of Vietnam where Agent Orange was sprayed and it was also measured in food by Baughman and Meselson of Harvard University in the 1970s. Levels were up to 1,450 parts per trillion (PPT) in milk lipid and were not detected in U.S. nursing mothers’ milk. Today, in the USA and also in Vietnam, 1 ppt of TCDD is an average adult blood or milk level except for specially exposed persons.

Beginning in 1984, Vietnamese human adipose tissue, milk, serum and levels in food, soil and sediment were measured by a loose collaboration of foreign scientists coordinated by Arnold Schecter with chemist colleagues from Canada, Germany, the USA, Finland, the Netherlands and elsewhere. They found elevated TCDD with an Agent Orange pattern in humans, soil, sediment and food up to decades after spraying ended.

Later, a Canadian environmental group, the Hatfields, conducted dioxin tests of the environment and then food and human tissues with similar findings, TCDD elevation in a minority of samples.

At the present time, the US and Vietnamese governments are using thermal methods to heat soil and remove chlorine from dioxin contaminated soils from certain areas including Da Nang and Bien Hoa, primarily from airfields with high levels. It is not certain how well and how costly this method will be.

Human health efforts by the two governments include assistance for vaccinations, AIDS/HIV, prosthetics and there may be a hospital based birth defect registry established with US partial support for each of these. At present, no human health studies are being conducted in collaboration with the USA.