According to Cancer Prevention Centers, twelve Colorado counties previously considered to be at moderate risk for radon exposure have been upgraded to the high-risk category. The change means all 64 Colorado counties are categorized as Zone 1 for radon, or high-risk, by the Colorado Department of Public Health and Environment. Counties in Zone 1 have an estimated indoor radon average greater than four picocuries per liter (pCi/L), the action level where the department and the U.S. Environmental Protection Agency recommend homeowners install mitigation equipment.

The 12 affected counties are: Alamosa, Archuleta, Conejos, Costilla, Eagle, Hinsdale, La Plata, Mineral, Rio Grande, Routt, Saguache and San Juan. Although the designation does not mean every home in these counties has radon above the action level, state officials strongly encourage Colorado residents to test their homes and to consider installing mitigation systems if radon levels exceed four pCi/L.

"We've always known radon was a problem in Colorado," said Chrystine Kelley, manager of the radon program at the department. "This new data confirms a need for heightened awareness, more testing and a more proactive mindset, such as building new homes with radon-resistant construction."

Radon, a colorless, odorless radioactive gas, is the second leading cause of lung cancer in the United States. Radon occurs naturally from the decay of uranium in soil and is abundant in Colorado. The only way to know if your household is being exposed to radon is to test. Test kits are inexpensive, and the tests are easy to perform.

The Health Department's re-categorization underscores the critical risks that radon presents to the residents of Colorado. Authorities recommend testing for radon in homes, businesses and other public buildings and that mitigation can be carried out. There are kits available in home improvement and DIY outlets for home testing for radon in Colorado and the Public Health Department offers coupons that can allay some of the $30-$40 cost. Once a test confirms the presence of radon, a licensed contractor certified to mitigate (remediate) radon in Colorado should be contacted.

Radon is known to cause over 20,000 deaths every year in the United States and Colorado is one of the most affected states. This initiative by the Health Department is a step in the right direction when it comes to reducing the mortality rate from lung cancer. You can learn more about radon gas and the new regulations within the state of Colorado at or by contacting the Colorado Department of Health.