Colorado has high levels of radon, which can cause lung cancer – here’s how to lower your risk

Radon exposure is the leading cause of lung cancer for people who have never used tobacco. Francesco Scatena/iStock via Getty Images

In Colorado, as of 2025, about 500 people a year die from lung cancer as the result of radon gas exposure. Nationally, the number of lung cancer deaths attributed to radon is about 21,000 per year.

Radon is present nearly everywhere outdoors, yet typically at levels that are not harmful. It becomes dangerous when it gets trapped and accumulates inside homes, schools and other buildings.