What is radon?

Radon is a colorless, odorless radioactive gas that can enter your home through cracks in concrete walls and floors and through floor drains. The most common source of radon is uranium that normally exists in the soil or rock on which homes are built. Problems show up when the concentration of radon builds up in a home or building. Both old or new homes can have problems with radon even if they don't have a basement.

The U.S. Surgeon General and the U.S. Environmental Protection Agency (EPA) recommend that all homes be tested for radon levels.

You can hire a qualified tester to do the test, or you can use a do-it-yourself test kit. Use only home tests that are labeled "meets EPA requirements." You can buy radon test kits by calling the EPA at 1-800-SOS-RADON (1-800-767-7236).

There are two types of tests. Both measure radon levels in the air.

• The short-term test kit stays in your home or office for 2 to 90 days. Radon levels vary daily and from season to season. So you may want to follow up the first short-term test with a second test.
• The long-term test kit stays in your home or office for more than 90 days. A long-term test will give more accurate results.

The EPA recommends placing the test kit in your home on the lowest level that you regularly use. If you have questions about radon in your house, you can get help from the EPA by calling 1-800-55-RADON (1-800-557-2366).

If tests find a high level of radon, you'll need to reduce it. There are two parts to this.

• Preventing radon from entering the building. The most common way to do this is through sub-slab depressurization, which vents air from beneath the foundation. This work should be done by a qualified contractor. Other control methods include sealing cracks in the foundation or walls and using air cleaners.
• Venting radon out of the building. After the radon is prevented from entering the building, venting can be done to reduce the level of radon. This may include using fans, blowers, and suction devices to remove radon in the air in crawl spaces, basements, and other areas.

Use an EPA-qualified contractor with proper training in radon reduction to help with this work.

After radon reduction or prevention procedures are done, the home or building should be retested. You may need to retest more than once. It is usually safe to live in the home or building while the radon is being vented, but you may want to confirm this with your local EPA office.

For general information about removing or reducing radon in your house, you can go to www.epa.gov/radon or call the Radon Fix-It Hotline at 1-800-644-6999. If you live outside the U.S., you can call your regional environmental protection office for more information.

Over time, exposure to radon can cause lung cancer. People who smoke have an even higher risk of lung cancer from radon exposure than people who don't smoke.

Radon exposure doesn't cause symptoms. Unless your home or office is tested for high radon levels, you may not realize that you are being exposed to dangerous levels of radon until you or someone in your family is diagnosed with lung cancer.