False Alarm?

For years the Environmental Protection Agency has urged Americans to check their homes for radon contamination. Seeping into basements from underlying rocks and soil, the colorless, odorless radioactive gas raises the risk of lung cancer. The EPA maintains that a household level of four picocuries of radiation per liter of air is enough to produce cancer in 13 to 50 of every 1,000 people who breathe it regularly. The agency estimates that at least 8 million homes exceed this level, warranting such measures as sealing foundation cracks.

But a growing number of scientists contend that radon's dangers are overstated. They point out that the EPA bases its warnings primarily on studies of lung-cancer rates among uranium miners. Such workers toil for years in subterranean pits where radon concentrations are thousands of times as high as levels in homes. In some studies, it was not clear how much of the cancer was caused by radon, how much by smoking cigarettes and how much by a combination of the two: researchers believe that radon poses a higher risk for smokers.

Before making major investments in radon abatement, homeowners should take these uncertainties into account. It cannot hurt to buy a radon-testing kit, which generally costs less than $25. If repeated tests indicate a high level, professional testing is needed. While there is no magic number, a radon level in the hundreds would probably be grounds for action. If sealing cracks does not solve the problem, radon can often be flushed out by installing special fans and ventilation ducts. Weighing the options, however, could be done more dispassionately if the EPA would tone down its frightening rhetoric.