Review of the radiation exposures of the Beaverlodge miners

Eldorado Nuclear Limited and its predecessor companies mined radioactive ores at Port Radium Northwest Territories, from 1930 to 1960 and in the Beaverlodge area of Northern Saskatchewan from 1949 to 1982. A refinery at Port Hope, Ontario started up in 1932, initially extracting radium, switching to uranium in the 1940s and phasing out radium work in 1954. The Eldorado Epidemiology Project was intended to follow up the health of all Eldorado workers to 1980. One of the objectives was to further dose-response knowledge, in particular for radon daughter exposure of uranium miners. Eldorado produced a nominal roll of employees, which was matched to the National Mortality Data Base of Statistics Canada. The study design and Canada's strict confidentiality laws precluded any mortality data being given to Eldorado. The matched data, together with radiation exposure estimates, were given to the National Cancer Institute of Canada Epidemiology Unit for analysis. The resulting excess relative risk estimate of 0.026/WLM for workers at Eldorado's Beaverlodge Operation is substantially higher than those arising from other uranium miner studies: Ontario 0.014, Malmberget 0.014, Colorado 0.006. Factors which could have contributed to the higher risk include: underestimation of radon daughter exposure at Beaverlodge, improper assignment of workers to a particular site, unrecorded radon exposure at other uranium mines, other work experience which increased the Lung cancer risk, and non-occupational radiation exposure