The Ohio Department of Health short term radon test kits. Radon is a colorless, odorless radioactive gas that forms when naturally occurring uranium decays. Radon gas is commonly found in rocks and soil and it enters homes through holes and cracks in the foundation. Prolonged exposure to radon levels above 4 picocuries per liter of air significantly increases the risk of lung cancer, even for nonsmokers. Residents must complete an application that asks questions about your home, such as when it was built, type of foundation, etc.