Radon is an invisible and odorless radioactive gas that occurs naturally with the breakdown of uranium in water, rock and soil. we are surrounded to some degree of radon gas levels.  and in low levels it does not pose a health risk. however, radon can accumulate to dangerously high levels in confined spaces such as basements and mines without adequate ventilation. High levels of radon over a prolonged time is a health risk. Radon is the second leading cause of lung cancer after smoking. Testing is the only way to check for radon levels in your home.