Understanding radon



  • Radon has no color, odor or taste and doesn't cause short-term symptoms of illness.
  • Radon causes cancer.
    • It's estimated to cause about 21,000 lung cancer deaths per year in the United States.
    • It's the second leading cause of lung cancer in the United States, according to the surgeon general.
    • Only smoking causes more lung cancer deaths.

Radon in Colorado

  • Radon is a naturally occurring radioactive gas that comes from the breakdown of uranium in the soil.
    • It's a gas that moves up through the soil to the atmosphere.
  • High radon levels have been found in all 50 states and in all parts of Colorado.
  • In Colorado, about half the homes have radon levels higher than the U.S. Environmental Protection Agency recommended action level of 4 picocuries per liter (pCi/L):

How radon gets into your home

  • Radon moves from uranium-bearing granite deposits in the soil to the atmosphere.
    • Your home sits on radon's pathway from the soil to the atmosphere.
    • Your home is usually warmer and has lower air pressure than the surrounding soil, so gases in the soil, including radon, move into your home.
    • The most common routes are:
      • Spaces between basement walls and the slab.
      • Cracks in foundations and/or walls.
      • Openings around sump pumps and drains.
      • Construction joints and plumbing penetrations.
      • Crawl spaces.
      • Well water with high radon concentrations.
  • ​​The age and/or type of home doesn't matter when it comes to whether high levels of radon are present.

Radon in schools

  • Schools are at risk from radon just like homes.
  • Colorado statute requires all schools to test for radon and to maintain records of the test results for disclosure on request.
    • The statute doesn’t require schools to mitigate, so it’s up to the school district and its constituents to address mitigation issues.