Lung cancer mortality (1950-80) in relation to radon daughter exposure in a cohort of workers at the Eldorado Beaverlodge uranium mine.

A cohort study of 8,487 workers employed between 1948 and 1980 at a uranium mine in Saskatchewan, Canada, has been conducted. A total of 65 lung cancer deaths was observed (34.24 expected, P less than 10(-5)). There was a highly significant linear relationship between dose and increased risk of lung cancer giving estimates for the relative and attributable risk coefficients of 3.28% per working level month (WLM) and 20.8 per WLM per 10(6) person-years. Age at first exposure had a significant modifying effect on risk. The interaction of exposure with age at observation fits a relative risk model well. The similarity of these results to a recent study of Swedish iron miners with similar levels of relatively low exposure suggests that exposure to radon daughter products may be a major contributory factor to lung cancer occurring among nonsmokers in the general population. The results also reinforce concerns as to the appropriateness of present occupational exposure standards.