Radon, a naturally-occurring invisible gas, is the second leading cause of lung cancer after smoking. Twenty-one thousand Americans die from radon-induced lung cancer each year. You can't see, smell or taste radon, but it may be a problem in your home. The good news is that radon exposure is preventable. The American Lung Association and the U.S. Environmental Protection Agency are committed to fighting radon. Now, we're enlisting others to help take the fight to a whole new level -- because no one should have to suffer from preventable radon-caused cancer.