UNC scientists investigated deaths among workers at the U.S. Department of Energy's Hanford Site in Richland, Wash. The Hanford Site produced plutonium for atomic weapons, including the first plutonium bombs dropped during World War II.
Researchers say the largest cancer risk from older-age exposures is for lung cancer.
"Findings of radiation-related cancer risks among nuclear workers have been questioned in the past by other scientists who concluded that most occupational exposures were too low to cause a detectable increase in cancer rates," said Dr. Steven B. Wing, associate professor of epidemiology at the UNC School of Public Health. "Predictions based on studies of survivors of the atomic bombings of Japan during the war suggested that cancer risks from radiation exposures of Hanford workers would be too small to detect."
The new study evaluated radiation risks by using measurements of workers' radiation exposures recorded on radiation-sensitive badges worn on the job, Wing said. Cancers were identified through death records. Researchers identified 8,153 deaths, including 2,265 from cancer, among 26,389 workers hired between 1944 and 1978 and followed through 1994.
"We found no relationship between radiation doses and deaths from causes other than cancer, primarily heart disease and stroke," he said. "Additionally, radiation doses received at younger ages were not associated with cancer deaths. However, readings on radiation badges worn by workers when they were ages 55 and above were associated with death rates for cancer, and particularly for lung cancer."
A report on the findings appears in the June 17 issue of Occupational and Environmental Medicine, a professional journal. Dr. David B. R
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Contact: David Williamson
919-962-8596
University of North Carolina at Chapel Hill
16-Jun-2005