Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all rock and soils. Radon usually moves from the ground up and migrates into homes and other buildings through openings in any ground contact floor or wall. Buildings trap radon inside, where it accumulates and may become a health hazard. Any home or building may have a radon problem, including new and old homes, well-sealed and drafty homes, and homes with or without basements.

Approximately 55 percent of our exposure to radiation comes from radon.

After smoking, radon is the second leading cause of lung cancer in the United States, with more than 20,000 Americans dying each year from radon-related lung cancer. Only smoking causes more lung cancer deaths and smokers exposed to radon are at an even higher risk than nonsmokers. Luckily, radon can be detected with a simple test and an elevated radon level can be remedied.

The U.S. Environmental Protection Agency (EPA) drives the national commitment to educate citizens about residential radon risks. To achieve this goal, the Agency coordinates regional and state-level efforts to reduce exposure to radon.

Radon in the air is measured in picocuries per liter (pCi/L). Where radon levels are four pCi/L or higher, the U.S. Environmental Protection Agency and the U.S. Surgeon General recommend that homeowners take action to reduce the radon level. It is estimated that nearly one in 15 American homes has a radon level that should be reduced. Testing your home is the only way to know. Radon can be detected with a simple test and an elevated radon level is best remedied by a professional radon mitigation specialist.

Lowering high radon levels requires technical knowledge and special skills. Citizens should use a contractor who is trained to fix radon problems. A qualified contractor can study the radon problem in your home and help you pick the right treatment method.

The primary method used to reduce or mitigate radon levels is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside, which is also called sub-slab depressurization, active soil depressurization, or soil suction. Generally indoor radon can be mitigated by sub-slab depressurization and exhausting such radon-laden air to the outdoors, away from windows and other building openings. The EPA generally recommends methods which prevent the entry of radon. Soil suction, for example, prevents radon from entering your home by drawing the radon from below the home and venting it through a pipe, or pipes, to the air above the home where it is quickly diluted and EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently.

An effective method to reduce radon levels in crawlspace homes involves covering the earth floor with a high-density plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the outdoors. This form of soil suction is called sub membrane suction, and when properly applied is the most effective way to reduce radon levels in crawlspace homes.

Radon Myths and EPA Facts


MYTH: Scientists aren’t sure radon really is a problem.
FACT: Although some scientists dispute the precise number of deaths due to radon, all the major health organizations (like the Centers for Disease Control and Prevention, the American Lung Association and the American Medical Association) agree with estimates that radon causes thousands of preventable lung cancer deaths every year. This is especially true among smokers, since the risk to smokers is much greater than to non-smokers.


MYTH: Radon testing is difficult, time consuming and expensive.
FACT: Radon testing is easy. You can test your home yourself or hire a qualified radon test company. Either approach takes only a small amount of time and effort.


MYTH: Homes with radon problems can’t be fixed.
FACT: There are simple solutions to radon problems in homes. Hundreds of thousands of homeowners have already fixed radon problems in their homes. Most homes can be fixed for about the same cost as other common home repairs; check with one or more qualified mitigators. Call your state radon office for help in identifying qualified mitigation contractors.


MYTH: Radon affects only certain kinds of homes.
FACT: House construction can affect radon levels. However, radon can be a problem in homes of all types: old homes, new homes, drafty homes, insulated homes, homes with basements, homes without basements. Local geology, construction materials, and how the home was built are among the factors that can affect radon levels in homes.


MYTH: Radon is only a problem in certain parts of the country.
FACT: High radon levels have been found in every state. Radon problems do vary from area to area, but the only way to know your radon level is to test.


MYTH: A neighbor’s test result is a good indication of whether your home has a problem.
FACT: It’s not. Radon levels can vary greatly from home to home. The only way to know if your home has a radon problem is to test it.


MYTH: Everyone should test their water for radon.
FACT: Although radon gets into some homes through water, it is important to first test the air in the home for radon. If your water comes from a public water supply that uses ground water, call your water supplier. If high radon levels are found and the home has a private well, call the Safe Drinking Water Hotline at 1-800-426-4791 for information on testing your water.


MYTH: It’s difficult to sell homes where radon problems have been discovered.
FACT: Where radon problems have been fixed, home sales have not been blocked or frustrated. The added protection is sometimes a good selling point.


MYTH: I’ve lived in my home for so long, it doesn’t make sense to take action now.
FACT: You will reduce your risk of lung cancer when you reduce radon levels, even if you’ve lived with a radon problem for a long time.


MYTH: Short-term tests can’t be used for making a decision about whether to fix your home.
FACT: A short-term test, followed by a second short-term test* can be used to decide whether to fix your home. However, the closer the average of your two short-term tests is to 4 pCi/L, the less certain you can be about whether your year-round average is above or below that level. Keep in mind that radon levels below 4 pCi/L still pose some risk. Radon levels can be reduced in most homes to 2 pCi/L or below. * If the radon test is part of a real estate transaction, the result of two short-term tests can be used in deciding whether to mitigate. For more information, see EPA’s “Home Buyer’s and Seller’s Guide to Radon“.