Environment: Danger Just Downstairs

An invisible, odorless, radioactive gas produced by the decay of uranium in rock and soil, radon can seep into homes through cracks in foundations and drains. Some houses in the Northeast have been found with dangerously high radon levels. Last week the Environmental Protection Agency announced that the health threat posed by radon may be greater than previously thought.

Surveying 11,600 houses in ten states from Wyoming to Alabama, EPA investigators found that 21% had radon levels exceeding EPA health standards. The American Medical Association promptly declared radon a "risk of substantial magnitude" but described as "somewhat uncertain" federal estimates that attribute 10% of lung-cancer deaths to the gas.