When it comes to testing for Radon, most inspectors do not offer this service. My company does. Radon is a colorless and odorless gas that is emitted from the soil. While most of Northeast Oklahoma is in a Zone 1 area (the lowest possible zone), there are 5 counties that are in a Zone 2 area. These counties are Sequoyah, Cherokee, Adair, Deleware and Mayes. Here is a link to the EPA’s Radon Zone Map.