ABSTRACT
2,3,7,8-tetrachlorinated dibenzo-p-dioxin (2,3,7,8-TCDD) is one of the extremely toxic chemicals produced as an unwanted contaminant of certain chemical manufacturing processes. 2,3,7,8-TCDD has been found as recently as 1980 in soil from Vietnam. The exposure of humans to 2,3,7,8-TCDD is unique in Vietnam, because over 400 pounds of pure 2,3,7,8-TCDD2 were sprayed over discrete areas in the form of Agent Orange. Pentachlorophenol (PCP), an antifungal agent used extensively as a wood and paper preservative by the Americans (and possibly the French) in the south of Vietnam, is also not known to have been used in the north. The findings of high levels of the chemically and toxicologically similar chlorinated dioxins and dibenzofurans in tissues of individuals in industrialized countries suggests a difficulty in performing clinical or epidemiological studies of the human health effects of dioxins in those countries.
