Denver, CO – As families across Colorado prepare for Thanksgiving, state health officials are warning about a silent, invisible danger that could be filling homes across the Rockies. The Centers for Disease Control and Prevention (CDC) and the Colorado Department of Public Health and Environment (CDPHE) say radon, a radioactive gas found in soil and rock, poses a major health risk during the winter months when homes are sealed tight against the cold.
Radon forms naturally when uranium underground breaks down, releasing gas that seeps into homes through cracks, drains, and foundation gaps. Because it’s colorless, odorless, and tasteless, families often have no idea it’s there.
The U.S. Environmental Protection Agency (EPA) ranks radon as the second-leading cause of lung cancer in the nation, claiming more than 21,000 lives annually. Colorado is among the highest-risk states in the U.S., with nearly 50% of homes testing above the EPA’s danger threshold of 4 picocuries per liter (pCi/L) — especially in Denver, Colorado Springs, and Fort Collins.
Testing is simple, inexpensive, and the only way to know if your home has a problem. Short-term test kits, available online, at hardware stores, or through the Colorado Radon Program, typically cost under $25 and take only a few days. The EPA recommends mitigation if radon levels are 4 pCi/L or higher, though no amount is completely safe.
If elevated levels are found, certified radon mitigation specialists can install systems that vent gas safely outdoors — often lowering concentrations by up to 90%.
“Radon doesn’t make a sound, doesn’t leave a smell — but it kills thousands each year,” CDC officials said. “Testing your home this Thanksgiving could be the simplest, most life-saving thing you do.”
With families across Colorado spending more time indoors this week, health officials urge residents to add radon testing to their winter safety plans before this invisible killer lingers through the season.
