BASF studies: epidemiological and clinical investigations on dioxin-exposed chemical workers

First in 1953 and again later in 1988, BASF Aktiengesellschaft, Ludwigshafen, Germany, faced production-related dioxin contamination problems. In both situations, the immediate actions were efforts to limit the potential for employee exposure. In 1953, after a reactor accident, the production of trichlorophenol was stopped and extensive clean-up and demolition work was undertaken. In 1988, major technical improvements were made to an extrusion blending process and the flame retardants were changed to substances that chemically should not be dioxin precursors. The health experience of the potentially exposed populations has been followed extensively in both situations. Five recent epidemiological investigations: a long-term mortality follow-up, a morbidity study, a clinical laboratory study, and a chromosome study of persons from the 1953 accident cohort, as well as immunological studies of employees assigned to the extrusion operations, are discussed. In addition, considerable dioxin biomonitoring data from blood lipids for both populations are summarized.