Mortality Rates Among Workers Exposed to Dioxins in the Manufacture of Pentachlorophenol

Objective: We sought to determine if workers exposed to dioxins in pentachlorophenol (PCP) manufacturing were at increased risk of death from specific causes. Methods: We examined death rates among 773 workers exposed to chlorinated dioxins during PCP manufacturing from 193 7 to 1980 using serum dioxin evaluations to estimate exposures to five dioxins. Results: Deaths from all causes combined, all cancers combined, lung cancer, diabetes, and ischemic heart disease were near expected levels. There were eight deaths from non-Hodgkin lymphoma (standardized mortality ratios = 2.4, 95% CI = 1.0 to 4.8). We observed no trend of increasing risk for any cause of death with increasing dioxin exposure. However, the highest rates of non-Hodgkin lymphoma were found in the highest exposure group (standardized mortality ratios = 4.5, 95% CI = 1.2 to 11.5). Conclusions: Other than possibly an increased risk of non-Hodgkin lymphoma, we find no other cause of death related to the mixture of the dioxin contaminants found in PCP. (J Occup Environ Med. 2009;51:1212-1219)