Estimating active bone marrow dose from occupational exposure to uranium at a former gaseous diffusion plant

Active bone marrow absorbed doses were estimated for 581 workers as part of a nested case-control study of multiple myeloma mortality at the Oak Ridge Gaseous Diffusion Plant (K-25). Uranium urinalysis results obtained by fluorometric and gross alpha measurements were available for about 20% of the 581 study subjects. These data were used to determine intakes of uranium as a result of occupational exposure during operation of the K-25 facility. Uranium solubility was inferred from the observed urinary excretion rate, job titles, and department codes. Data suggest that most study subjects were exposed to uranyl fluoride, a relatively soluble uranium compound. The median cumulative bone marrow dose determined for subjects with bioassay data was 0.06 mGy with a geometric standard deviation of 4.48. Subjects without bioassay data were assigned cumulative bone marrow dose based upon job titles and department codes.