While the number of homes in Minnesota tested for radon has increased more than threefold since 2010, only about one percent of properties in the state were tested in the most recent five-year period, a recent analysis by the Minnesota Department of Health revealed.

The same analysis of test data from 2010 to 2014 found that 2 in 5 homes – about 40 percent – have dangerous levels of radon — 4pCi/L or above — and that the average level of radon in Minnesota homes is about 4.6 pCi/L, more than three times the national average.

“The increase in home testing is a positive trend, but it’s clear from the data that people are being exposed to high levels of radon who don’t know it,” said Dan Tranter, supervisor of the Indoor Air Program for MDH.

Radon, an odorless, colorless gas, poses a significant health risk and is the leading cause of lung cancer in nonsmokers. MDH recommends that homeowners conduct an inexpensive, do-it-yourself test of their home for radon during Radon Awareness Month in January.

In Minnesota, winter is the best time to test homes for radon. Radon occurs naturally in Minnesota soils. It can enter homes through cracks or openings in walls or foundations. The only way for a resident to know if their home has high levels of radon is to test. Radon is a problem everywhere in Minnesota, and everyone in every county should test their home. Renters should ask their landlords to test their homes or provide previous test results. If renters test their homes, they should discuss the results with their landlords.

More than 21,000 lung cancer deaths each year in the U.S. are linked to radon. Fortunately, the risk is largely preventable, by testing homes and fixing radon problems.

Testing is easy, inexpensive and only takes three to seven days. The best time to test is during the heating seasons, but testing can be done year-round. Test kits are available at city and county health departments, many hardware stores or directly from radon testing laboratories.

Tests should be done in the lowest level of the home that is frequently occupied. If your home’s test results show it is at or above 4 piC/L, you should consider verification testing and having a radon reduction system installed.

MDH analyzed five years of test data, from 2010 to 2014, representing more than 86,000 properties.

The number of properties tested rose from 7,073 in 2010 to 24,716 in 2014, the most recent year analyzed. The analysis found that two in five homes have dangerous levels. In addition, the analysis found that the average radon level in Minnesota homes is about 4.6 pCi/L compared to 1.3 pCi/L nationwide. For levels of 4 pCi/L or higher, MDH recommends taking action, including installing a radon mitigation system.

“This increase in home radon testing may be due to a new disclosure and notification law in home sales, radon awareness campaigns, local outreach partnerships and an improving economy,” Tranter said. “But we have more work to do to get more homes tested.”

To help residents get a more accurate picture of radon levels in their counties, MDH launched an interactive map tool in July.

January is National Radon Action Month and Gov. Mark Dayton has proclaimed January as Radon Action Month in Minnesota. During the month of January, the Minnesota Department of Health will sponsor TV, radio and internet ads in the Twin Cities and Greater Minnesota to encourage people to test their homes. In addition, MDH has partnered with many local public health departments to make test kits available to local residents at low or no cost.

For more information on radon testing and mitigation, visit www.health.state.mn.us/radon or call the MDH Indoor Air Unit at 651-201-4601 or 1-800-798-9050.