With Minnesota homes shut tight against the cold, dangerous levels of cancer-causing radon gas can build up during the winter months.

To draw attention to this risk, the Minnesota Department of Health (MDH) and its partners mark January as radon action month, urging Minnesotans to test their homes for radon. This year, a new online tool is available to help target the efforts.

A new interactive map from MDH shows radon testing rates for every census tract in Minnesota. Census tracts are areas within counties about the size of a neighborhood. The map reveals that testing rates are still low in Minnesota, with only about 1 percent of properties tested every year, despite years of public awareness campaigns urging all homeowners and residents to test.

State health officials say two in five homes in Minnesota are likely to have dangerous levels of radon. The new map shows wide variations in testing rates across the state, as well as significant disparities. Testing rates are generally lowest in areas with more households living in poverty.

Radon is an odorless, colorless gas that occurs naturally in Minnesota soils, and enters homes through cracks or openings in walls or foundations. Radon is linked to more than 21,000 lung cancer deaths in the U.S. each year. Radon is the second-leading cause of lung cancer in the United States today. The average radon level in Minnesota is more than three times higher than the average U.S. radon level. 

“This map is important, because it helps us see where we need to target resources and improve outreach to increase testing,” said Dan Tranter, MDH indoor air supervisor. “This map can also help homeowners and residents by showing where radon hot spots are – areas where more homes have radon levels above four picocuries per liter (pCi/L), the action level to fix homes.”

According to the map from the Minnesota Public Health Data Access Portal of MDH, there were 79 properties tested annually (2010-16) for radon per 10,000 housing units. Of these properties tested, 44 percent had elevated radon levels, at or above 4.0 pCi/L.

The census tract with the lowest rate of testing had less than one property tested per 10,000 units or .01 percent. The highest census tract had 321 properties tested annually per 10,000 housing units or 3.21 percent.

“We recommend that every home in Minnesota be tested at least every five years, which means about 20 percent of properties should be tested every year,” Tranter said. “We hope this map will be a tool that Minnesotans, including public health officials and other radon partners, can use to help more people understand the importance of radon testing and thereby increase our overall rate.”

Even if one’s county has a lower average radon level, it is important to test their own home, since radon levels can vary widely between homes – even in the same neighborhood. The only way to know is to test.

In homes found to have high radon levels, radon reduction (mitigation) typically involves installing a venting pipe and fan to pull the gas from under the home to the outside. This reduces the amount of radon in the home to low levels.

You can find a list of radon measurement and mitigation professionals on the MDH Web site.

During National Radon Action Month in January, MDH is partnering with local public health departments and other organizations to raise awareness and make test kits available to Minnesotans at low or no cost.

For more information on radon testing and mitigation, visit www.health.state.mn.us, or call the MDH indoor air unit at (651) 201-4601 or 1-800-798-9050.

– Graphic courtesy of the Minnesota Department of Health