Because you can’t see radon and you can’t smell it, taste it, hear it, or feel it, the exposure to unhealthy radon gas levels could be a hidden hazard in your home, especially when it’s at elevated levels. In Montana, radon has been found throughout the state, and Gallatin County has some of the highest levels of radon in the State. Use this interactive mapper to explore average State and County levels:

What is radon?

Radon is a colorless, odorless, radioactive gas that forms naturally in the soil. Radon is produced when uranium in the soil breaks down.

Why is radon a concern?
Radon is known to cause lung cancer and it can seep into our homes and workplaces through cracks and openings in the floors and crawlspaces. When this happens, radon becomes part of the air we breathe. Any workplace or home can have radon including new and old, well-sealed and drafty and homes and building with or without basements.

Can radon make me sick?

  • When a person is exposed to radon over many years, the exposure can increase the risk of lung cancer. Radon is the third-leading cause of lung cancer in the United States. Radon is the leading cause of lung cancer in non-smokers. 1
  • Risk of lung cancer from radon is almost 10 times higher for smokers compared to those who have never smoked. Smoking and radon together create greater risk of lung cancer than either one. 2
  • Breathing radon does not cause any short-term health effects, such as shortness of breath, coughing, headaches, or fever.

Who is at risk?

  • Everyone exposed to radon over a long period of time is at risk for lung cancer.
  • Smokers are at higher of lung cancer.
  • In Montana, we have high levels of radon in our soils. Data collected on indoor air levels indicates that most counties in Montana have average levels higher than 4 picocuries per liter (pCi/L), which is the level at which EPA recommends radon mitigation.

How can risk be reduced?

Test your house for radon. We don’t compete with private industry and can’t test your home; but do provide information and test kits. Short-term (2 to 4 days) and long-term (3 months minimum) radon test kits are available for purchase in the Environmental Health Office at 215 West Mendenhall #108 in Bozeman.

Quit Smoking: Call the MT Tobacco Quit line at 1-800-QUIT-NOW

For FAQ’s on Radon visit:

Call the Montana Radon Hotline: 1-800-546-0483

For any questions about radon in Gallatin County, call the Gallatin City-County Health Department’s Environmental Health Services at 406-582-3120, or email




2 Risk-Reduction Strategies to Expand Radon Care Planning with Vulnerable Groups, Table 1, Laura S. Larsson, Ph.D., M.P.H., B.S.N.