Radon is a naturally occurring radioactive breakdown product of uranium that can dissolve and accumulate in ground water.
Radon is the second leading cause of lung cancer in the United States, after smoking.
EPA is encouraging states to adopt this more cost-effective approach, which would address radon in indoor air while requiring individual water systems to reduce the higher levels of radon in drinking water. Aeration of water to promote the release of radon is very effective and one of the more affordable water treatment technologies available. The 1996 Safe Drinking Water Act Amendments required EPA to establish several new health-based drinking water regulations. The first of these, announced by President Clinton in December 1998, was for cryptosporidium and other disease-causing microbes and for potentially harmful byproducts of the water treatment process. Today's multimedia proposal for radon is the second of these new regulations.