By the year 2025, an estimated 500 individuals in Colorado are projected to succumb annually to lung cancer, a direct consequence of exposure to radon gas. On a national scale, the annual death toll from lung cancer linked to radon exposure hovers around 21,000 individuals.
Radon is ubiquitous in outdoor environments, generally present at concentrations that pose no significant health threat. Its hazardous nature emerges when it becomes trapped and accumulates within enclosed spaces such as residences, educational institutions, and other structures.
This naturally occurring radioactive gas, radon, originates from the decay of uranium, a dense metallic element found within the earth’s soil. Its invisibility and odorless nature render radon a particularly insidious danger. As radon gas forms in the soil, it ascends and infiltrates buildings, regardless of their age or construction, through fissures in foundations, compromised seals around sump pumps and drainage systems, and unfinished crawl spaces.
A significant portion of the population remains oblivious to the radon concentrations within their homes. It is currently estimated that only about half of all households in Colorado have undergone radon testing. Consequently, a substantial number of Colorado residents may be unknowingly subjected to elevated radon levels.
While tobacco consumption stands as the primary determinant of lung cancer risk, accounting for roughly 86% of all diagnosed cases, radon emerges as the leading etiological factor for lung cancer among individuals who have never engaged in smoking.
Furthermore, radon amplifies the risk of lung cancer among tobacco users due to a synergistic effect. Approximately 7 out of every 1,000 non-smokers who experience prolonged exposure to elevated radon concentrations face a potential lifetime risk of developing lung cancer.
The risk associated with radon exposure is entirely preventable. In my capacity as a cancer epidemiologist, my objective is to ensure all Colorado inhabitants are apprised of their home’s radon levels and empowered to implement appropriate measures to curtail exposure, thereby safeguarding themselves and their families from the peril of lung cancer.
Radon Intrusion in Dwellings
Due to Colorado’s distinctive geological composition, which includes extensive mountainous terrain characterized by granite rock rich in uranium, radon concentrations tend to be higher within the state compared to other regions.
Colorado ranks among the top ten states nationwide exhibiting the highest radon levels. Approximately 50% of Colorado homes tested for radon reveal concentrations exceeding the Environmental Protection Agency’s recommended threshold of 4 picocuries per liter (pCi/L).
The average radon concentration found in Colorado homes is 6.4 pCi/L, a level comparable to undergoing 200 chest X-rays annually. Radon levels exhibit variability across Colorado’s 64 counties, influenced by their specific topography and soil composition.
If a dwelling lacks adequate ventilation, radon can accumulate indoors. Upon decay, radon releases radioactive particles that, when inhaled, can inflict damage upon the cells lining the lungs.
More precisely, these particles possess the capability to disrupt the chemical bonds within a cell’s DNA. If these disruptions remain unrepaired, they can initiate the development of cancerous cells. Prolonged exposure to substantial radon concentrations over an extended period can lead to lung cancer. Analogous to the impact of tobacco use, it is the cumulative burden of radon exposure that escalates the cancer risk.
Fortunately, effective strategies exist to prevent radon from infiltrating and building up within our homes. Radon mitigation systems, employing fans and piping, are designed to extract radon gas from beneath the home’s foundation and expel it outdoors. These systems have demonstrated the capacity to reduce indoor radon levels by as much as 99%.
Assessing and Mitigating Your Risk
The process of testing your residence for radon is straightforward and remains relatively economical. Test kits are deployed in the lowest occupied level of a house, apartment, condominium, or townhome and remain in place for a designated duration. The EPA advocates for testing in all residential units situated below the third story.
Available testing methods include short-term analyses, conducted over periods ranging from two to 90 days, and long-term assessments, which extend for 90 days or more. Long-term tests provide a more precise estimation of average annual radon concentrations. Upon completion, tests can be dispatched directly to a laboratory for analysis.
The typical cost for test kits is under $50, and they may also be acquired at no charge from numerous sources, including the University of Colorado Anschutz Cancer Center. As of February 2026, the cancer center has facilitated the distribution of over 1,600 test kits to individuals across 55 Colorado counties. It is noteworthy that nearly 40% of the tests distributed to date have indicated radon levels surpassing the EPA’s established threshold.
The EPA recommends conducting tests over multiple months, particularly during colder periods when windows and doors are typically secured, thereby trapping radon indoors. Extended testing provides a more comprehensive understanding of the home’s average annual radon concentration.
Diminishing Your Exposure Risk: Radon Remediation
Individuals discovering radon levels in their homes at or exceeding 4 pCi/L are advised to pursue remediation measures. These interventions may encompass the sealing of fissures in basement walls and foundations, as well as the installation of a fan and vent pipe to extract radon gas from beneath the dwelling and discharge it externally. The cost of remediation can range from $1,000 to $3,000, contingent upon the structural characteristics and geographical location of the home.
Support services are accessible for individuals facing financial constraints who require radon mitigation. Colorado’s state health department offers a low-income radon mitigation assistance program, which can cover the costs of radon remediation for eligible applicants based on income criteria.
While radon is imperceptible, its deleterious effects on human health are undeniable and largely preventable. By taking proactive steps today—testing your home, disseminating this vital information, and seeking assistance when necessary—you are actively contributing to a healthier future for yourself and your community.
