We evaluated radiation exposures and extended vital status follow-up and death certificate retrieval for a cohort of 33,459 prime contractor employees with at least one external dosimetry record who were hired between 1944 and 1978 and employed at least 180 days at the US Department of Energy's plutonium production facility at Hanford, W A. In this population, 8% of annual external dosimetry records (N=32,323) were missing. We developed an estimation procedure which predicted that approximately 19 Sv of external dose was missed. Evidence from quantitative analyses of dose records as well as historical documentation suggested that (non-missing) doses near the detection limit were assigned to zero during some historical periods. For this cohort, quantification ofintemal doses from plutonium using computerized records was not feasible due to low and variable coverage of bioassay monitoring programs, variation in bioassay detection limits, and lack of information on physical and chemical forms of plutonium and routes of exposure. Therefore, to evaluate risks of plutonium work we used detailed work history information to develop a simple job-exposure matrix based on job titles and departments or work areas. In a sub-cohort of26,389 workers who had no off-site doses, no record of employment at other DOE facilities, and no extended employment prior to meeting the study's entry criteria, 2,673 men and 392 women worked injobs involving routine potential for plutonium exposure. Plutonium workers had low death rates compared to other workers, particularly for cancer causes, however, death rates in this group tended to increase with increasing length of employment in plutonium jobs, particularly for employment at older ages. Adjusted relative risks per decade of employment in routine plutonium jobs at ages 50 and above were 1.22, 1.30, 1.63, and 2.03 for natural causes of death, all cancers, cancers of tissues where plutonium deposits, and lung cancer, respectively.
Ionizing-radiation; Radiation-facilities; Radiation-exposure; Radiation-injury; Radioactive-materials; Cancer-rates; Lung-cancer; Respiratory-system-disorders; Pulmonary-system-disorders; Plutonium-compounds; Workplace-monitoring; Humans; Racial-factors; Sex-factors; Mortality-rates; Mortality-surveys
Steve Wing; Department of Epidemiology' 2101F McGavran-Greenberg Hall; School of Public Health, CB#7435; University of North Carolina; Chapel Hill, NC 27559-7435