McLean County Radon Awareness Program

High radon levels have been found in every county in Illinois. Therefore, the only way to know whether or not a home has a high radon level is to test. To help people know the potential for high radon in their regions, the U.S. EPA has published a nationwide Map of Radon Zones. On the map, zone 1 equals high potential, zone 2 equals moderate potential and zone 3 equals low potential. The high potential zone predicts a potential indoor radon screening level greater than 4 pCi/L. In Illinois, zone 1 covers the central and northern half of the state, including McLean County. Although this map may be helpful in predicting potential radon concentrations, it should not be used to predict individual home radon concentrations. Only a radon test can determine the actual radon level.