The latest report from the National Research Council (NRC) on the hazards of radon exposure has more bad news for smokers: If you are living in one of the 6% of homes with high levels of this omnipresent radioactive gas, your chances of getting lung cancer skyrocket.
The NRC panel estimates that radon contributes to about 12% of all lung cancer deaths--or 15,000 to 22,000 a year. Of the victims, almost 90% are smokers. Thus, while reducing radon levels in homes would prevent one-third of the casualties, the committee found, avoiding the deadly combination of smoking and radon would prevent almost all of them.
The estimated radon death toll is in line with earlier NRC estimates. "The ballpark is the same, but there's a great deal more certainty," says panel chair Jonathan Samet, an epidemiologist at Johns Hopkins University. "We've increased the amount of information by an order of magnitude."
The committee arrived at its conclusions after analyzing 11 studies of 68,000 miners exposed to radon and eight large studies of residential exposure, as well as laboratory studies. They were unable to discern any threshold level of exposure beneath which cancer risk disappears.
Some scientists think the NRC has overestimated the radon toll. "I believe they were carried away by their statistics," says epidemiologist Naomi Harley of New York University Medical Center. The Environmental Protection Agency, which commissioned the report, is not expected to take any action in response to it any time soon.