When radon starts to decay, very tiny radioactive particles are released. If you inhale these particles, they enter the lungs and may cause cancerous changes in nearby cells. If you breathe in radon, you have a greater chance of getting lung cancer.³

Radon is the second leading cause of lung cancer, second only to tobacco smoke. It is responsible for about 21,000 deaths from lung cancer per year in the United States.¹

The U.S. Surgeon General and the U.S. Environmental Protection Agency (EPA) recommend that all homes be tested for radon levels.

The combination of smoking and radon exposure can greatly increase your risk of developing lung cancer. If you smoke or live with someone who smokes and you live or work in a place with dangerous radon levels, your risk of lung cancer is significantly higher than for someone who has never smoked but lives or works in places with unsafe radon levels. It is never too late to reduce your risk of lung cancer. Don't wait to test for and fix a radon problem. And if you smoke, try to quit. For more information, see the topic Quitting Tobacco Use.

Radon exposure does not produce immediate symptoms. You may not realize that you are being exposed to dangerous levels of radon until you or someone in your family is diagnosed with lung cancer.