American Uranium Miners and Lung Cancer.
Pneumoconiosis, Proceedings of the International Conference, Johannesburg 1969 1970:569-571
Results of periodic examinations of uranium miners in the United States were reviewed and an ongoing followup mortality study of former miners was described. Individual estimates of cumulative radiation exposure were made for all miners in terms of working level months (WLM) and working level (WL) of exposure to radon (10043922) daughters during the period from 1950 to 1963. Follow up was from 1960 to October 1, 1967. There were 62 cases of lung cancer among 398 deaths recorded in a population of 3,414 uranium miners, as compared to ten cases expected; most of the cancers occurred in miners who had at least 10 years of occupational exposure to uranium mining. The excess of respiratory cancer deaths increased according to the increase of WLM. For estimated cumulative exposure categories up to 839WLM, lung cancer excess was three to four times greater than expected. Above this level, excess lung cancer rates increased markedly with dose, up to about 38 fold excess for exposures over 3720WLM. The excess lung cancer in smokers was ten times higher than that of nonsmokers. Undifferentiated small cell carcinomas, especially of the oat cell type, were the most frequent types of lung cancer among uranium miners, as compared to epidermoid types prevailing in nonminers. It was found that bone and urine levels of lead-210 (14255040) and polonium-210 (13981527) correlated well with exposure levels, and urine levels could be used to estimate exposure provided sufficient time had passed since last exposure. Reference was made to the fact that the permissible levels of exposure to radon daughters in uranium mines were to be gradually lowered from 12 to 4WLM per year starting in 1971.
Epidemiology; Mortality-rates; Underground-miners; Heavy-metals; Radiation-hazards; Exposure-limits; Ionizing-radiation; Lung-cancer;
10043-92-2; 14255-04-0; 13981-52-7;
Pneumoconiosis, Proceedings of the International Conference, Johannesburg 1969