Radon is the second leading cause of lung cancer. There are approximately 28,000 lung cancer deaths attributed to radon each year. There are also approximately 21,000 non smokers who die of lung cancer each year.

Long-term exposure to radon, in small or large amounts, can develop into lung cancer. Decaying radon releases tiny radioactive particles that can be inhaled. These particles attach to lung tissue and cause damage, resulting in lung cancer. The chances of developing lung cancer are increased for smokers

The risk of getting lung cancer for those who are exposed to radon compared to those who smoke and have radon exposure can be seen at the following Web site: http://www.epa.gov/docs/radon/risk_assessment.html.

Click to view the risk of radon exposure compared to cigarette usage.

According to the EPA charts found on the above link, a person exposed to radon levels of 3.2 pCi/L, 24 hours per day, their entire life, will have the same risk of getting lung cancer as a smoker in an area with very low radon. That computes to the equivalent of smoking 25 cigarettes per day.

The EPA outlines the Health risks of Radon at the following site:
http://www.epa.gov/radon/healthrisks.html