Being exposed to radon for a long period of time can lead to lung cancer.
Radon gas in the air breaks down into tiny radioactive elements (radon progeny)
that can lodge in the lining of the lungs, where they can give off radiation. This
radiation can damage lung cells and eventually lead to lung cancer.
Cigarette smoking is by far the most common cause of lung cancer in the
United States, but radon is the second leading cause. Scientists estimate that
about 21,000 lung cancer deaths per year are related to radon.