Environment: Tracking The Radon Threat

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In Bismarck, N. Dak., last week, real estate agent Al Schaible sighed as he anticipated a wave of requests for tests for the radioactive gas radon from buyers and sellers of homes. "Checks like that were unheard of before this," complained Schaible. "A lot of people are talking about it." Indeed they are. The message of the Federal Government's latest public-health advisory on the radon danger, released last week by the Environmental Protection Agency and the Surgeon General's office, is ominous: a new survey of homes in seven states shows that high levels of cancer-causing radon are more widespread than was believed. Declares Assistant Surgeon General Vernon Houk: "I would not buy a house, I would not move into a house, without knowing what the level of radon is."

The alert touched off a wave of frantic calls to environmental officials and contractors around the country as homeowners inquired about how to test for the odorless, colorless gas. In Illinois officials answered 250 calls in two days alone. Schaible was in an especially hot spot. According to the new report, 63% of homes tested in North Dakota had radon levels exceeding the federal standard of 4 picocuries per liter of air, giving the state the worst rate of incidence of those surveyed. (A picocurie is a trillionth of a curie, a standard measure of radiation.) Even more startling was the 184-picocurie level found in one home in Stark County in the southwestern part of the state. Prolonged exposure to that much radon is the rough equivalent of smoking four packs of cigarettes a day or getting 2,000 chest X rays a year.

It is not the first time the EPA has red-flagged radon. A year ago, agency researchers surveyed some 11,000 homes in ten states and found that 1 in 5 had potentially dangerous levels of the gas. The EPA was justifiably concerned, since radon, which is produced by the decay of uranium in rocks and soil, can cause lung cancer if it seeps up from the ground into homes through cracks in foundations and drains. A number of studies, including data collected from thousands of uranium miners, have indicated that radon causes between 5,000 and 20,000 lung-cancer deaths a year, making it the second leading cause of that form of cancer after smoking. Cigarette smoking is by far the primary culprit, however, contributing to 85% of the nearly 140,000 lung-cancer deaths a year in the U.S.

The new survey looked at an additional 11,000 homes in North Dakota, Minnesota, Pennsylvania, Indiana, Massachusetts, Missouri and Arkansas. The results were even more serious than those in the earlier sampling: the tests, which consisted of a single measurement taken during the winter months, found radon danger in nearly 1 out of 3 homes. Extrapolating from the two studies, the EPA concluded that in the 17 states surveyed, the number of homes with levels higher than 4 picocuries is around 3 million. Some of them have levels over 20 picocuries. Moreover, even states with low reported overall levels of radon may have individual homes with high levels.