Radon Health Risks

Indoor radon is the second-leading cause of lung cancer in the United States and breathing it over prolonged periods can present a significant health risk to families.

People can be exposed to radon primarily from breathing radon in air that comes through cracks and gaps in buildings and homes. Because radon comes naturally from the earth, people are always exposed to some level of radon. The U.S. Environmental Protection Agency (EPA) and the Surgeon General’s office estimate radon is responsible for more than 20,000 lung cancer deaths each year in the U.S. About 2,900 of these deaths occur among people who have never smoked.

When you breathe in radon, radioactive particles from radon gas can get trapped in your lungs. Over time, the damage caused by these radioactive particles increases the risk of lung cancer. It may take years before health problems appear. Lung cancer claims more lives each year than do colon, prostate, ovarian and breast cancers combined. The chances of getting lung cancer are higher if your home has elevated radon levels and you smoke or burn fuels that increase indoor particles.

While scientists understand radon’s health risks for adults, in children it leads to a set of health hazards that are still being researched. As the bodies of children are much smaller, their breathing rate is higher than that of an adult. This results in more radon exposure and increased opportunities for radon to be inhaled by children. In addition to this higher dose of radon children also have smaller lungs that can become damaged much more quickly than an adult’s lungs.

On January 13, 2005, Dr. Richard H. Carmona, the U.S. Surgeon General, issued the national health advisory on radon below.

"Indoor radon is the second-leading cause of lung cancer in the United States and breathing it over prolonged periods can present a significant health risk to families all over the county," Dr. Carmona said. "It's important to know that this threat is completely preventable. Radon can be detected with a simple test and fixed through well-established venting techniques."

The EPA recommends taking action to reduce radon in homes that have a radon level at or above 4 picocuries per liter (pCi/L) of air (a “picocurie” is a common unit for measuring the amount of radioactivity). Your chances of getting lung cancer from radon depend mostly on:

  • How much radon is in the location in your home where you spend most of your time (e.g., the main living and sleeping areas)
  • The amount of time you spend in your home
  • Whether you are a smoker or have ever smoked
  • Whether you burn wood, coal, or other substances that add particles to the indoor air

Having your home tested is the only effective way to determine whether you and your family are at risk of high radon exposure. Contact the Radon Program for more information on the health risks of radon and what you can do to protect your family from radon.

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Health Impacts of Radon Exposure