Radon (Rn)

The most common source of indoor radon is uranium in the soil or rock on which homes are built. As uranium naturally breaks down, it releases radon gas which is a colorless, odorless, radioactive gas. Radon gas enters homes through dirt floors, cracks in concrete walls and floors, floor drains, and sumps. When radon becomes trapped in buildings and concentrations build up indoors, exposure to radon becomes a concern.

Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and homes with or without basements.

Sometimes radon enters the home through well water. In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.

Health Effects of Radon

The predominant health effect associated with exposure to elevated levels of radon is lung cancer. Research suggests that swallowing water with high radon levels may pose risks, too, although these are believed to be much lower than those from breathing air containing radon. Major health organizations (like the Centers for Disease Control and Prevention, the American Lung Association (ALA), and the American Medical Association) agree with estimates that radon causes thousands of preventable lung cancer deaths each year. EPA estimates that radon causes about 14,000 deaths per year in the United States--however, this number could range from 7,000 to 30,000 deaths per year. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.