An Analysis of the Mortality of Workers in a Nuclear Facility

Abstract

Data from the Hanford plant [Washington, USA], where many workers are employed in jobs involving some exposure to radiation, are analyzed. Mortality from all causes, all cancers and specific cancer types is related to personnel and exposure data for the population at risk. Results are compared with those of other investigators. The mortality of Hanford workers is first compared with that of the USA population, and then related to radiation exposure without reference to an outside population. The first analysis shows a substantial healthy worker effect and no significantly high standardized mortality ratios for specific disease categories. A test for association of mortality with levels of radiation exposure reveals no correlation for all causes and all cancer. A statistically significant test for trend is obtained for multiple myeloma and cancer of the pancreas but no evidence of a positive correlation is found for 13 other cancer sites including those more typically associated with radiation exposure, such as myeloid leukemia and lung cancer. The possibility of other occupational exposures and the lack of reliability with respect to diagnosis of cancer of the pancreas must be considered in interpreting these results. The identified correlations result from a small number of deaths with exposures greater than 15 rem. The lack of correlation for all cancers and for leukemia is by no means inconsistant with current estimates of such effects given the amount of radiation exposure that is received.