Radon is a naturally occurring radioactive gas that is estimated to cause thousands of lung cancer deaths in the U.S. each year. It can enter and contaminate a house built on soil and rock containing uranium deposits or enter through water drilled in uranium rich soil. Radon becomes a lethal health threat when it is trapped in tightly sealed homes that have been insulated to keep in heat or have poor ventilation, when it escapes from building materials that have incorporated uranium-filled rocks and soils (like certain types of composite tiles or bricks), or when it is released into the air from aerated household water that has passed through underground concentrations of uranium. Problems occur most frequently in areas where rocky soil is relatively rich in uranium and in climates where occupants keep their windows tightly shut.
The Environmental Protection Agency estimates that about six million American homes have unacceptably high levels of radon. While radon has been found in homes across the United States, some areas have higher radon potential than others. See the EPA Map of Radon Zones for details.
States often require sellers to disclose defects in the home, including environmental hazards that they know about. (See Required Disclosures When Selling U.S. Real Estate for background information.)
For example, California’s Real Estate Transfer Disclosure Statement requires sellers to inform buyers of any environmental hazards, including radon gas, of which they are aware. These disclosure requirements are described in detail in the Nolo book How to Buy a House in California. And Illinois requires sellers to provide buyers two pamphlets about radon hazards before signing the contract. See Illinois Home Sellers: Disclosures Required Under State Law for details. The resources listed below can help you find your state radon rules.
Whether or not your state requires disclosure of radon, the EPA recommends that sellers test their home before putting it on the market. Testing is the only way to identify a home’s radon levels.
Fortunately, there are usually simple, inexpensive ways to measure indoor radon levels, and good ventilation will effectively disperse the gas in most situations. These measures range from the obvious (open the windows and provide cross-ventilation) to the more complex (sealing cracks in the foundation, or sucking radon out of the soil before it enters the foundation and venting it into the air above the door through a pipe). According to the EPA, there are often simple solutions to radon problems.
For information on the detection and removal of radon, see the Radon section of the EPA website, or call the Radon Hotline at 800-767-7236. The EPA site has links to state and local radon programs and provides information on finding a qualified radon reduction provider. You can also download a copy of the EPA Home Buyer’s and Seller’s Guide to Radon on the EPA site; this useful booklet includes useful advice on testing for radon and how to lower radon levels in your home.