Radon

Image Gallery Radon enters a home primarily through its floor and foundation, though building materials and water may also be sources.

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Up to 25% of all U.S. homes may have hazardous levels of radioactive gas.

You're breathing it right now. Radon, an invisible, odorless, radioactive gas, is present everywhere in our atmosphere. A natural product of the breakdown of uranium, radon emanates from rock and soil but is usually so diluted by air that it poses a minimal health risk. Problems arise when humans construct radon traps — buildings — and then live in them.

Houses with dangerously high radon levels have been found in all 50 states. There's no question that some regions are more prone to radon problems than others, but no area is immune. And even the fact that a neighbor's home with similar construction has been tested and found to be safe is no guarantee that yours will receive a similar report.

As many as 10 million U.S. residences may have significant radon contamination, and there is now nearly universal agreement among experts that all homes should be tested. If you haven't yet had your home examined for radon, read the sidebar on testing and pick a service.

Finding that your home does have a radon problem is no cause for panic. But, depending on the concentration, it may call for prompt action. First, retest thoroughly. Use multiple detectors — both carbon and alpha track — and place them so as to get a better idea of where the concentrations are highest in your house. Your state radiation protection agency or the commercial tester may provide information or assistance in proper screening. If the problem is confirmed, it's time to get to work.

How Bad?

The results of radon tests are usually expressed in units called picocuries per liter of air (pCi/L). Without getting into the physics of radiation, that means that there are about two radioactive disintegrations of radon 222 in each liter (9/10 quart) of air every minute. As you can see, this has nothing directly to do with alpha particles bombarding lung tissues and causing mutations. However, through a complicated (and still controversial) process, health physicists can relate units of radioactivity to health risk.

RADON
It's the number-two cause of lung cancer deaths.

Among various public, commercial and international organizations, the call for alarm on radon comes at between two and 11 pCi/L, but the EPA says that you should take remedial action if the concentration exceeds four pCi/L. According to EPA scientists, over a lifetime that level of exposure will cause between 13 and 50 cancer deaths per 1,000 people — about three times the number caused by the average indoor level of 1.5 pCi/L. One laboratory, Air Chek, reports that about 25% of the homes it has tested have exceeded four pCi/L.

Since radon is assumed to cause some cancers at any detectable concentration, it would be ideal to eliminate it entirely from our homes. In practice, however, this is difficult, if not impossible, to achieve. Radon moves easily through the smallest of cracks and is able to penetrate (though slowly) concrete and other building materials. Efforts to reduce concentrations far below four pCi/L will probably be futile.

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