ABSTRACT
The case of chlorinated dioxin illustrates many of the difficulties encountered in assessing health risks following long-term, low-dose exposure to environmental chemical contaminations. In 1971, approximately 29 kg of 2,3,7,8-tetrachlorodibenzo-p-dioxin-contaminated sludge wastes, which originated as a by-product of hexachlorophene production in a southwest Missouri plant, were mixed with waste oils and sprayed for dust control throughout the state. The lack of any direct measure of body burden or exposure substantially hindered attempts to assess the degree of exposure to and concomitant health risk posed by environmental chlorinated dioxins. The public health agencies involved continue to review environmental sampling data on new suspected sites and to develop public health advisories. The potential health effects considered in this study were based primarily on the animal toxicology of chlorinated dioxin and results from studies of long-term industrial and accidental acute human exposures. Information on health effects involving nonoccupational environmental exposure is sparse.
