Key Issues
Radiation Safety at Nuclear Power Plants: Studies Look at Public, Workers
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Doll Review
British epidemiologist Sir Richard Doll dismissed the Gardner hypothesis in a 1994 issue of Nature. The Gardner hypothesis had prompted two families to sue British Nuclear Fuels plc, the company that operates Sellafield. They lost the suit in 1993. In his review of the evidence available to the court, Doll said Gardner’s theory of radiation-damaged sperm did not accord with what is known about radiation genetics or childhood leukemia. He noted that offspring of Japanese atomic bomb survivors showed no abnormal genetic activity, even though the Japanese survivors had received much higher radiation doses than the Sellafield workers.
Oak Ridge Study
A study conducted for the Oak Ridge Associated Universities by Steven Wing of the University of North Carolina was published in 1991. The study looked at the 1,524 deaths from all causes among the 8,318 white males hired at Oak Ridge National Laboratory between 1943 and 1972. When compared with all U.S. white males, the Oak Ridge workers had lower than average mortality risks for most causes of death. The study identified 346 cancer deaths among the workers, whereas 438 normally would be expected. The exception was leukemia: Oak Ridge workers were at a 63 percent higher risk of death than all white males. There were 28 deaths from leukemia, whereas 17 normally would be expected.
The same workers had been the subject of an earlier study, which found no increased leukemia risks and no association between cancer mortality and occupational exposures to radiation and other substances. The researchers had no explanation for the difference between the studies. The study does observe an apparent statistical association, but there was insufficient data to conclude that low-level radiation exposure caused the higher than anticipated deaths from leukemia. The study did not take into account possible exposures to hazardous materials, smoking habits or lifestyles.
Navy Shipyard Workers
A study by researchers at The Johns Hopkins University, released in 1991, found no evidence that the workers who serviced nuclear-powered ships for the U.S. Navy between 1957 and 1981 were harmed by their on-the-job exposure to low levels of radiation.
Commissioned by the U.S. Department of Energy, the study examined the records of 70,000 civilian male workers employed at two private and six naval shipyards. The group included 38,220 workers who were exposed to low levels of radiation while on the job, and 32,510 nonexposed workers. The cancer death rate among the radiation-exposed shipyard workers (most of whom accumulated exposures of greater than 500 rems) was lower than among the nonexposed workers and slightly lower than the rate for the U.S. white male population.
The rate for leukemia, specifically, was slightly lower than expected—both among the exposed and nonexposed shipyard workers. In addition, the overall death rate among radiation-exposed shipyard workers was significantly lower than the rate for U.S. white males.
The last finding is not unexpected, since worker populations in general tend to have below-average mortality rates. This is because workers must be healthy to be hired, and they must re-main healthy to continue their employment.
Doll Review
British epidemiologist Sir Richard Doll dismissed the Gardner hypothesis in a 1994 issue of Nature. The Gardner hypothesis had prompted two families to sue British Nuclear Fuels plc, the company that operates Sellafield. They lost the suit in 1993. In his review of the evidence available to the court, Doll said Gardner’s theory of radiation-damaged sperm did not accord with what is known about radiation genetics or childhood leukemia. He noted that offspring of Japanese atomic bomb survivors showed no abnormal genetic activity, even though the Japanese survivors had received much higher radiation doses than the Sellafield workers.
Oak Ridge Study
A study conducted for the Oak Ridge Associated Universities by Steven Wing of the University of North Carolina was published in 1991. The study looked at the 1,524 deaths from all causes among the 8,318 white males hired at Oak Ridge National Laboratory between 1943 and 1972. When compared with all U.S. white males, the Oak Ridge workers had lower than average mortality risks for most causes of death. The study identified 346 cancer deaths among the workers, whereas 438 normally would be expected. The exception was leukemia: Oak Ridge workers were at a 63 percent higher risk of death than all white males. There were 28 deaths from leukemia, whereas 17 normally would be expected.
The same workers had been the subject of an earlier study, which found no increased leukemia risks and no association between cancer mortality and occupational exposures to radiation and other substances. The researchers had no explanation for the difference between the studies. The study does observe an apparent statistical association, but there was insufficient data to conclude that low-level radiation exposure caused the higher than anticipated deaths from leukemia. The study did not take into account possible exposures to hazardous materials, smoking habits or lifestyles.
Navy Shipyard Workers
A study by researchers at The Johns Hopkins University, released in 1991, found no evidence that the workers who serviced nuclear-powered ships for the U.S. Navy between 1957 and 1981 were harmed by their on-the-job exposure to low levels of radiation.
Commissioned by the U.S. Department of Energy, the study examined the records of 70,000 civilian male workers employed at two private and six naval shipyards. The group included 38,220 workers who were exposed to low levels of radiation while on the job, and 32,510 nonexposed workers. The cancer death rate among the radiation-exposed shipyard workers (most of whom accumulated exposures of greater than 500 rems) was lower than among the nonexposed workers and slightly lower than the rate for the U.S. white male population.
The rate for leukemia, specifically, was slightly lower than expected—both among the exposed and nonexposed shipyard workers. In addition, the overall death rate among radiation-exposed shipyard workers was significantly lower than the rate for U.S. white males.
The last finding is not unexpected, since worker populations in general tend to have below-average mortality rates. This is because workers must be healthy to be hired, and they must re-main healthy to continue their employment.
