Radon is a colorless, odorless radioactive gas that forms as a result of the natural decay of uranium underground. This Radon Information Sheet (PDF) explains more. 

According to the EPA, radon is the number one cause of lung cancer among non-smokers.

The only way to know if your home has high radon is to test. Free test kits are available to Pitkin County residents by filling out this online mail order form. After you submit a mail order form, a kit will be mailed to your home. Kits are NOT available for pick-up through Pitkin County or City of Aspen offices.