Health Effects of Radon: Basics

What health effects are associated with radon exposure?

The Surgeon General has warned that radon is the second leading cause of lung cancer in the United States. There are currently no conclusive data on whether children are at greater risk than adults from radon. No specific subtype of lung cancer is associated with radon exposure.

Only smoking causes more cases of lung cancer. If you smoke and you are exposed to elevated radon levels, your risk of lung cancer is especially high. The U.S. Environmental Protection Agency provides radon risk comparison charts for people who smoke and those who have never smoked. Stop smoking and lower your radon level to reduce your lung cancer risk.

Radon gas decays into radioactive particles that can get trapped in your lungs when you breathe. As they break down further, these particles release small bursts of energy. This can damage lung tissue and lead to lung cancer over the course of your lifetime. Not everyone exposed to elevated levels of radon will develop lung cancer, and the amount of time between exposure and the onset of the disease may be many years.

Breathing radon does not cause any short-term health effects such as shortness of breath, coughing, headaches, or fever.

In 1998, the National Academy of Sciences (NAS) released the Biological Effects of Ionizing Radiation (BEIR VI) Report, "The Health Effects of Exposure to Indoor Radon." The study reviewed and evaluated data from many prior studies and drew conclusions. It fully supports estimates by the EPA that radon causes about 21,000 lung cancer deaths per year. Though some people debate the number of deaths, it is widely agreed that radon exposure is the second leading cause of lung cancer.

Research suggests that swallowing water with high radon levels may pose risks, too, although risks from drinking water containing radon are much lower than those from breathing air containing radon. A NAS report on radon in drinking water, "Risk Assessment of Radon in Drinking Water," (link is external) was released in 1998. It concluded drinking radon in water causes about 19 stomach cancer deaths per year.

The EPA provides more information about health effects from radon in their publication, A Physician's Guide to Radon.