You can't see radon. You can't smell it. The greatest radon risk is its invisibility in American homes. Radon is an extremely toxic gas that is best known for its use in cancer treatments. Most radon gets into homes and buildings from the soil underneath. While there has been some concerns that radon risk are increased in homes with granite countertops, health officials have found no connection between the countertops and elevated levels of radon in the home. Even though radon helps in cancer treatments, it is known to cause some cancers, particularly lung cancer since most of it is inhaled. The radon decay settles in the lungs and affects cells in the airways. A radon test kit can reduce radon risks for homeowners. The Environmental Protection Agency (EPA) recommends that radon tests be conducted every two years. The EPA has a list of providers that can help homeowners if radon levels are high in their home.