BLOOD LIPID CONCENTRATIONS OF DIOXINS AND FURANS IN A SAMPLE OF BASF EMPLOYEES INCLUDED IN THE IARC REGISTRY OF WORKERS EXPOSED TO PHENOXY ACID HERBICIDES AND OR CHLOROPHENOLS/

Depending on process conditions, polychlorinated dibenzo-p-dioxins (PC DDs) and polychlorinated dibenzofurans (PCDFs) may be generated as low -level byproducts of chlorophenol and chlorophenoxy herbicides manufac ture. A stratified random sample of 20 active employees from a cohort of phenoxy herbicide workers was selected in 1995 for determining PCDD and PCDF congeners in blood lipids to assess the extent of past PCDD and PCDF exposure in this cohort and whether that exposure might expla in site-specific cancer findings in the total cohort. This cohort is i ncluded in the IARC International Registry of Persons Exposed to Pheno xyacid Herbicides and Their Contaminants. For the 19 persons who parti cipated, median PCDD and PCDF concentrations were comparable to backgr ound concentrations in the general population. Median levels of 2,3,7, 8-tetrachlorodibenzo-p-dioxin, the sum of hexachlorodibenzo-p-dioxin, pentachlorodibenzofurans, and two dioxin toxicity equivalents values w ere statistically higher in 7 employees assigned to synthesis operatio ns than for 12 employees assigned to other operations. However, the PC DD and PCDF concentrations were low relative to those seen in other di oxin-exposed cohorts. We conclude that PCDD and PCDF exposures of coho rt members are unlikely to explain the elevated standardized mortality ratios observed in this cohort for several cancer sites.