Radon is a cancer-causing radioactive gas. Radon is the second leading cause of lung cancer in the US and the leading cause among non-smokers. You can’t see, smell, or taste radon, but it may be a problem in your home and only smoking causes more lung cancer deaths every year. About 2,900 of these deaths occur among people who have never smoked. If you smoke and your home has high radon levels, your risk of lung cancer greatly increases.