Mortality in Workers Exposed to 2,3,7,8-Tetrachlorodibenzo-p-dioxin at a Trichlorophenol Plant in New Zealand

Objective: We examined the overall mortality rates of 1599 workers employed between 1969 and 1988 at a New Zealand site, which manufactured trichlorophenol. Methods: We developed exposure estimates for 2,3,7,8-tetrachlorodibenzo-p-dioxin from a serum dioxin evaluation and used standardized mortality ratios (SMR) and proportional hazards models to evaluate risk from exposure. Results: Among exposed workers, deaths from total cancers (SMR = 1.1, 95% confidence intervals [CI]: 0.9-1.4), non-Hodgkin lymphoma (SMR = 1.6, 95% CI: 03-4.7), and ischemic heart disease (SMR = 1.1, 95% CI: 0.9-1.5) were slightly greater than expected, whereas deaths from lung cancer (SMR = 0.8, 95% CI: 0.4-1.5) were less than expected. We observed no significant trends with exposure levels. Conclusions: Although this study is small, we found no increasing trend of cancer or disease risk with increasing 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure with the possible exception of all cancers combined. (J Occup Environ Med. 2009;51:1049-1056)