A new study suggests that people living near the Three Mile Island nuclear power plant in 1979, when it released radioactive gas into the air, may have suffered from a higher rate of some cancers in the first several years after the accident. But many epidemiologists are skeptical of the provocative findings, which were released today in a report in the current issue of the journal Environmental Health Perspectives.
After the accident, residents near the plant in Pennsylvania began to report nausea, vomiting, hair loss, and skin rashes--signs of radiation exposure. Exactly how much radiation was released is a big question. In 1990, a report by Maureen Hatch, now at the Mount Sinai School of Medicine in New York, and colleagues at Columbia University concluded that not enough radiation had escaped into the environment to raise cancer risk by 1985. But after reexamining the region's cancer statistics and measured radiation levels, epidemiologist Steven Wing and his colleagues at the University of North Carolina, Chapel Hill, concluded that more radiation may have escaped than was measured and that the risk of some cancers did rise.
Wing found that people presumed to have been exposed to the highest doses of radiation were almost twice as likely to develop lung cancer as were those who received the lowest doses. His team also found that the risk of adult leukemia was almost seven times higher for those in the highest exposure group.
Other experts are unimpressed. For instance, some epidemiologists point out, smoking may have contributed to the increased lung cancer risk. As for the leukemia numbers, such a high risk usually signifies a real effect, says Charles Land, a statistician at the National Cancer Institute. But he points out that the data are insufficient to show a trend in two more reliable indicators of radiation exposure--childhood leukemia and thyroid cancer. The reanalysis, Land concludes, "is not convincing." Wing could not be reached for comment.
More data that could perhaps settle the issue are on the horizon. A study of cancer rates near Three Mile Island since 1985 by epidemiologist Evelyn Talbott of the University of Pittsburgh is expected to be submitted for publication this summer. Her analysis will include thyroid cancer and childhood leukemia through 1992 for 32,000 people living within 8 kilometers of Three Mile Island. The study is controlling for confounding factors such as smoking and employment in the nuclear industry.