The reanalysis does not indicate that radiation is more likely to cause leukemia than solid tumors or that there is a reduced cancer effectiveness of radiation at low dose levels. However, the estimated proportion of radiogenic cancers was much higher for the 175 nonfatal cancers than for the 1,732 fatal cases.
The analytic file consists of seven records per worker for a cohort of 44,101 workers. The cohort was restricted to individuals who worked at Hanford between 1944 and 1978. The follow-up period for this reanalysis runs from January 1944 through December 1986. The file contains demographic data, offsite doses, internal exposure data, annual external doses, work history, and vital status data. Due to the many job titles at Hanford, six job categories were established: professional, managerial, clerical, crafts people, blue collar, other, and not specified. Data include the date on which a worker was first monitored (by urinalysis) for internal deposition as well as the dates on which the result was first greater than zero (i.e., measurable), the result was greater than the standard error, and the result was greater than twice the standard error. Results of in vivo counting include the years at which depositions of one, two, or three nuclides were detected. There were 9,443 deaths identified through the follow- up period of December 31, 1986.
Workers at Hanford were involved in a variety of activities resulting in exposure to radiation, including reactor operations, chemical separation processes, treatment and storage of hazardous waste, and biological and engineering research. Personal dosimeters were first used in 1944. The doses contained in the file are expressed in centirad. Internal exposure data were collected and evaluated for all individuals who worked in locations where there was a potential for intake of radioactive materials.