Tennessee Radon Program

Frequently Asked Questions

Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in rocks and soils. Radon gas is tasteless, colorless and odorless. The only way to know if it is in your home is to test for it.

Yes. The Tennessee Department of Environment and Conservation (TDEC) considers radon to be a serious problem in our state.  Tennessee does have higher than the national average of radon in homes. No matter where you live in Tennessee, there is the potential for radon to enter your home. Regardless of your zone designation or geographic location, all homes should be tested for radon. 

Radon gas has been identified as the second leading cause of lung cancer, second only to cigarette smoking. Radon is responsible for about 21,000 lung cancer deaths every year.  About 2,900 of these deaths occur among people who have never smoked.

As radon gas breaks down, it emits high-energy alpha particles. These particles are in the air we breathe, and once inhaled, they can be deposited in our lungs. The energy associated with these particles can alter cell DNA, thus increasing the risk of lung cancer. Persons who smoke and live in a home with elevated radon levels are at a very high risk to develop lung cancer.

Fortunately, radon does not generally present a health risk outdoors because it is diluted in the open air. Radon can, however, build up to dangerous levels inside a house, any other buildings, or caves.

Radon is a radioactive gas that comes from the soil. Most homes and buildings are constructed atop the soil on a property. Air pressure inside your home is usually lower than pressure in the soil beneath and around your home's foundation. Because of this difference in air pressure, your house acts like a vacuum, drawing radon in through foundation cracks and other openings. Radon may also be present in well water and can be released into the air in your home when water is used for showering and other household uses. In most cases, radon entering the home through water is a small risk compared with radon entering your home from the soil.

Radon is measured in picocuries per liter of air or pCi/L. The average concentration of radon in outdoor air is 0.4 pCi/L. The average radon concentration in the indoor air of America’s homes is about 1.3 pCi/L The U.S. Environmental Protection Agency (EPA) has established 4 pCi/L as an action level in which one should initiate measures to reduce the amount of radon in a home. However, even levels below 4 pCi/L carry some risk. The EPA recommends that if the radon level detected in a home is between 2 and 4 pCi/L, steps should be taken to reduce it to below 2 pCi/L.

If the results of your radon test exceeded 4 pCi/L, TDEC and EPA recommend that a follow-up test be conducted. If the follow-up test results (or the average of the two tests) also exceed 4 pCi/L, it is recommended that your home should be fixed to reduce the radon levels. High radon levels in your home can be mitigated – often through measures such as ventilation. We highly recommend using a certified professional for mitigation. The National Radon Proficiency Program and AARST certify professionals. Please check their websites for information about qualified professionals in your area. 

Carefully read the instruction sheet that comes with your radon test kit before starting your radon test. Our lab has identified common user errors related to duration of testing, such as: leaving the test out too long, improperly recording the test start and end times, and not returning the test to the lab in a timely manner. 

Follow these tips for optimum test accuracy:

  • Set an alarm or reminder on your calendar to take down the test at the end of 3-5 days;
  • Run the test for a maximum of 5 days;
  • Record the test time carefully; and
  • Mail the kit to the lab for analysis as soon as the test is completed. Postage is prepaid!



Lexi Brown

Office of Sustainable Practices

Radon Hotline

This Page Last Updated: January 10, 2023 at 2:37 PM