MDH: 40% of homes in Minnesota have dangerous levels of radioactive gas

It's important to test your home for radon, especially now when so many people are spending more time at home due to COVID-19, health officials say.

The Minnesota Department of Health (MDH) is reminding Minnesotans to test their house for radon, especially since so many people are spending more time at home due to the COVID-19 pandemic. 

Radon is an odorless, colorless, and tasteless radioactive gas that occurs naturally in the soil across Minnesota. The radon gas can move up into your home and accumulate in the air. Too much radon can cause serious health risks, including lung cancer, but it's largely preventable with testing and mitigation systems. 

“Radon testing and mitigation increased from 2010-15, and it has held steady in the last five years,” Dan Tranter, supervisor of the Indoor Air Program at MDH, said in a news release Tuesday. “Unfortunately, many people are still being exposed to high levels of radioactive radon who don’t know it. With more people working and schooling from home, it’s especially important now to test your home.”

About 40% of homes in Minnesota have dangerous levels of Radon, the release said. The only way to know if the lung cancer-causing gas is present in your home is to test for it, but few do. 

MDH says only about 1% of homes in Minnesota are tested annually for radon when it is recommended that at least 20% of homes get tested every year, noting that testing and mitigation is less frequent in communities with lower incomes and that have more renters. 

MDH says radon is a "serious public health concern," noting it is estimated that 21,000 people a year die in the U.S. from lung cancer caused by radon exposure.

Radon in Minnesota 

The average level of radon in Minnesota (4.5 picocuries of radon per liter of air or pCi/L) is more than three times higher than the average radon level in the United States (1.3 pCi/L), MDH notes. That's thanks to the state's geology and the fact that our homes are closed up or heated for much of the year, which can result in higher radon levels.

While any radon level poses a health risk (it's not possible to reduce radon to zero), MDH highly recommends that homes with radon levels of 4 pCi/L or higher install mitigation systems, which help reduce the level of radon to safer levels. 

And there are a lot of homes with radon levels that are considered unsafe. MDH says more than two in five homes have radon levels that pose a "significant health risk." The map below shows the percentage of homes in each county that got a radon test result of 4 pCi/L or higher between 2010-2018 – the darker the color, the higher the percentage. 

This map shows the percent of properties tested for radon from 2010-2018. The color reflects the percent of properties that had a radon test result of 4 pCi/L or greater – the darker the color, the more homes got that result. 

This map shows the percent of properties tested for radon from 2010-2018. The color reflects the percent of properties that had a radon test result of 4 pCi/L or greater – the darker the color, the more homes got that result. 

That map is among the interactive maps MDH has on its website to illustrate the prevalence of high radon levels in Minnesota. 

Since January is National Radon Action Month, MDH is working to raise awareness about the importance of getting your house tested through advertising and billboards. It is also working with health agencies and vendors to make test kits available to Minnesotans at low to no cost. 

How radon tests work

MDH recommends a home be tested for radon right away if they haven't been tested before. And at a minimum, homes should be tested every five years (even those that previously tested low) or sooner. 

Homes that have radon mitigation should be tested every two years, MDH says. It also recommends getting a radon test when you move to a new home, you're rehabbing a building that exposes openings to the soil, your ventilation/heating/cooling is altered significantly, or if extreme weather may have affected a prior test. 

This time of year (the heating season) is the best time to test for radon, but a home can be tested for it year-round.

Testing can be done by licensed professionals or by buying a test kit for $5-30 online, from a hardware store or from a local health agency (here is MDH's webpage on where to get a radon test). 

Short-term tests involve placing a testing device in the lowest level of your home, like the basement, for 2-5 days. The device will measure how much radon is in your home. If levels are low (0-1.9 pCi/L), MDH recommends you perform a short-term test again in 2-5 years (save your results after every test). If levels are 2-8 pCi/L, MDH says you should perform a follow-up long-term test, which involves a testing device being placed in a home for a minimum of 90 days to measure the annual average of radon in a home. 

If the result of the initial short-term test is greater than 8 pCi/L, MDH recommends performing a follow-up short-term test. If the second test – either the long-term or short-term – has radon levels of 2-3.9 pCi/L, homeowners should consider installing a radon mitigation system. If levels are 4 pCi/L or greater, MDH highly recommends installing a radon mitigation system. 

The cost of a radon mitigation system depends on how your home was built, but can range from $1,500 to $2,500 (financial assistance is available in some cases), MDH's website says

MDH's website has more information on radon, its prevalence in Minnesota, and how to mitigate it.

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