Radon is released from the ground into outdoor air but can accumulate and reach harmful levels when trapped in homes and other buildings. Radon is an odorless, colorless gas and is currently the leading cause of lung cancer for non-smokers. Approximately 450 people die each year in North Carolina from radon-induced lung cancer. Additionally, the risk factor for lung cancer among current or former smokers of tobacco increases by 10 times if they live in a home with elevated radon.