University of Toledo’s Ohio radon concentrations web site might help you decide, but you should also know that there is no known safe level of radon and that all buildings (new, old, well-sealed, drafty and homes with or without basements or crawlspaces) can be affected by radon. The EPA’s Map of Radon Zones also indicates that homes and buildings in Ohio are at higher risk of elevated levels of radon. Many counties in Ohio fall into Zone 1, the zone where there is the highest potential of radon levels exceeding 4pCi/L. At this level, the EPA strongly recommends that the home or building conduct radon remediation.