Of all the unwelcome house guests you may ever host, few are as nasty as radon. 

The colorless, odorless gas occurs naturally in Minnesota soils and is found at elevated levels in nearly 40 percent of all homes in the state. It also is the leading cause of lung cancer among non-smokers. In fact, each year this unwelcome house guest kills more than 21,000 people across the country. While there are cheap and easy ways to test for radon, many people are unaware of the risks and may not be getting the help they need to be safe.

Fortunately, the radon risk is largely preventable through testing homes and eliminating radon problems through improved ventilation and other measures. With more people working from home, it’s more important than ever to test homes for radon because testing is the only way to know if a home has radon levels at or above the level that presents a health risk. 

During January, Radon Action Month, the Minnesota Department of Health (MDH) is making a special push to urge everyone to test their home for radon. 

“Unfortunately, many people are still exposed to high levels of radioactive radon without being aware of it and this puts them at increased risk for lung cancer,” said Dan Tranter, supervisor of the MDH Indoor Air Program.  “We’ve heard a lot of common misunderstandings that discourage people from testing their home for radon.” 

For example, many people think their home does not need to be tested, or that if they test once they don’t need to test again, or if their neighbor’s radon level is low, they don’t need to test. 

Testing should be conducted in all homes, regardless of foundation type, soil type, age, presence of an air exchanger, or insulation, Tranter said. Even if the initial test shows the radon level is low, it’s a good idea to retest at least every five years because levels may change. Homes with mitigation systems should also be re-tested. The monitors on mitigation systems do not show the radon level, so it’s important to re-test at least every two years. New homes are built with radon resistant features, but they can still have elevated radon and should be tested.

MDH is partnering with local public health departments and other organizations to make test kits available to all Minnesotans at low or no cost. Participating agencies and vendors can be found on MDH’s Radon Testing website. Hardware stores may also stock test kits. Licensed professionals can also conduct testing. 

To help residents get a more accurate picture of radon levels in Minnesota, MDH developed a series of maps showing information about Radon in Minnesota. Some of the key findings were:

• The average radon level in Minnesota homes is about 4.5 pCi/L compared to 1.3 pCi/L nationwide. 
• Only about 1% to 2% of homes in Minnesota are tested annually; health officials recommend that at least 20% be tested annually.
• Testing and mitigation are less frequent in communities with lower incomes and more renters. 

Health professionals recommend testing for radon during real-estate transactions. Sellers must disclose any prior radon testing and provide a two-page publication to buyers under state law. Radon tests should be incorporated into a home inspection. MDH licenses home inspectors and other professionals who test for radon. A list of currently licensed radon measurement professionals can be found on the Find a Radon Measurement Professional page on the MDH site.

Tests should be done in the lowest level of the home that is frequently occupied. Test devices are usually placed in the home for two to five days. The best time to test is during the heating season, but testing can be done year-round. 

In homes with high radon levels, radon reduction typically involves installing a venting pipe and fan to pull the gas from under the home to the outside. Professionals conducting radon mitigation must be licensed by MDH, follow standards, and affix an MDH tag to the system. A list of licensed radon mitigation professionals can be found on the Find a Radon Mitigation Professional page on the MDH website. 

MDH conducts free inspections of radon mitigation systems installed after June 1, 2020. The inspections ensure systems were installed correctly, to make sure they meet minimum requirements. Contact the MDH Indoor Air Unit to request an inspection at [email protected].

More information about radon in Minnesota is available on the MDH website at Radon in Homes or by calling the MDH Indoor Air Unit at 651-201-4601 or 1-800-798-9050.