Where does radon gas come from?
Radon comes from the breakdown of naturally-occurring radioactive elements (such as uranium and thorium) in soils and rocks. As part of the radioactive decay process, radon gas is produced. The gas moves up through the soil to the surface, where it can enter homes, schools and the workplace through cracks and other holes in the foundation. In some cases, radon can enter buildings through well water and come from building materials. Any home can have a radon problem – old or new homes, well-sealed or drafty homes, and homes with or without basements.
For more information about radon in your home, visit the EPA's Radon web area.