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Originally published Friday, October 12, 2012 at 1:34 PM

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How to test a home for radon gas

All homes have radon, but not all homes have elevated levels of radon.

Dwight Barnett Scripps Howard News Service

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Home Fix

Radon is a radioactive, colorless, odorless, tasteless gas that occurs as uranium or thorium decays in the soils. Radon can be found all over the globe wherever there are soils; therefore, it occurs naturally in the air we breathe every day. When radon gas enters a home or other building through cracks, sump pits or other natural openings in or under the home, the gas can accumulate to a point where it becomes a serious health hazard.

According to the U.S. Environmental Protection Agency, radon is the second-most-frequent cause of lung cancer, after cigarette smoking, causing more than 20,000 lung-cancer deaths per year in the United States.

All homes have radon, but not all homes have elevated levels of radon. Some estimates are that 1 in every 15 homes has an elevated level of radon gas.

As the radon gas decays inside the home, it produces new elements called “radon daughters or progenies” that are solids that stick to dust particles that can be inhaled. These radon-contaminated dust particles then stick to the airways of the lungs, increasing the chances of developing lung cancer.

Every home should be checked for radon. A test can be as easy as placing a charcoal canister inside a basement or bedroom for several days or months and then sending the canister to a certified laboratory for analysis. Charcoal canisters can be found at most home and big-box stores.

The canister should be left inside the home with the windows and doors closed, except for normal entry and exit. Every time a door or window is opened, the air pressure inside drops. This is when radon-contaminated air from under the foundation enters the home.

Radon also can enter during heavy rains (it’s water-soluble) or when there are strong winds that lower the air pressures in the home.

During a real-estate transaction, time is of the essence, so a more sophisticated method of testing is performed by a licensed radon tester using state-of-the-art equipment for a minimum of 48 hours. If you have a well, the water also should be checked for radon gas, which dissipates when one showers or bathes.

Do-it-yourself radon-water test kits can be purchased online for less than $30.

A “Citizen’s Guide to Radon” can be found at and a radon-concentration map of the U.S. can be found at

Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home improvement questions at C. Dwight Barnett, Evansville Courier & Press, P.O. Box 268, Evansville, Ind. 47702 or email him at Sorry no personal replies. Always consult local contractors and codes.