Radon Gas: A Silent Threat in Colorado Homes
Radon gas exposure contributes to approximately 500 lung cancer deaths annually in Colorado as of 2025, and about 21,000 nationally. Radon is a naturally occurring radioactive gas resulting from uranium breakdown in soil. It is undetectable by sight or smell, and becomes dangerous when trapped indoors, entering buildings through foundations and other openings. While tobacco use is the primary cause of lung cancer, radon is the leading cause among non-tobacco users and exacerbates risk for tobacco users.
Radon is a naturally occurring radioactive gas, undetectable by sight or smell, that becomes dangerous when trapped indoors, and is the leading cause of lung cancer among non-tobacco users.
Only an estimated 50% of Colorado homes have been tested for radon, potentially leaving many residents unknowingly exposed to elevated levels.
Radon Levels in Colorado
Colorado's geology, including granite-rich mountainous regions, results in higher radon levels compared to many other states, placing it among the top 10 states for high radon levels. Approximately 50% of Colorado homes tested have radon levels exceeding the Environmental Protection Agency (EPA) threshold of 4 picocuries per liter (pCi/L), with the state's average radon level at 6.4 pCi/L.
Inadequate ventilation allows radon to accumulate indoors. As radon decays, it releases radioactive particles that can damage lung cells' DNA, potentially leading to cancer with prolonged exposure.
Testing and Mitigation
Radon exposure is preventable, and testing homes for radon is simple and relatively inexpensive, with kits often costing less than $50. The EPA recommends testing all residential units below the third floor. Short-term tests last 2-90 days, while long-term tests (90+ days) provide a more accurate annual average.
For homes with radon levels at or above 4 pCi/L, mitigation is recommended. Mitigation systems typically involve sealing foundation cracks and installing fans and vent pipes to draw radon from beneath the home and release it outdoors. These systems can reduce indoor radon levels by up to 99% and generally cost between $1,000 and $3,000. Resources like Colorado's state health department offer low-income assistance programs for eligible residents.
The University of Colorado Anschutz Cancer Center has distributed over 1,600 test kits, with nearly 40% revealing levels above the EPA threshold.