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What is radon? And how does it get into our homes?

Good Question: What is radon?
Good Question: What is radon? 03:03

ST. PAUL, Minn. — A potentially life-threatening gas enters Minnesota homes at higher rates than other states.

During Lung Cancer Awareness Month, we wanted to better understand: What is radon? How does it get into our homes?

A competitive market the past several years has forced many prospective home buyers to get creative with their offers, sometimes at their own risk.

"Unfortunately, we did see a drop off in real estate testing in 2022 compared to 2020-2021," said Dan Tranter, indoor air supervisor for the Minnesota Department of Health. 

He's talking about testing for radon, which gets skipped when home buyers drop the home inspection to make their offers stand out.

What is radon? It is a colorless and odorless gas that homeowners are unaware is potentially around them. Minnesota is known for having high levels of radon in its soil. 

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"It's a type of radiation. It comes from uranium. As uranium breaks down, it turns into radon," said Tranter.

Once in the soil, radon is released into the outdoor air but also into our homes through the foundation. It seeps through cracks or gets sucked in by machines like water heaters.

MDH estimates that 40%, or two out of five homes, have high levels of radon inside.

"Radon's a type of radiation when you breathe it in for a long period of time, like months to years, it can damage your lung cells which can lead to lung cancer," he said. 

According to the EPA, radon is the number one cause of lung cancer in nonsmokers, killing about 21,000 people per year.


Bonnie Mueller, an avid runner, suddenly couldn't do one of her favorite hobbies 10 years ago. 

"It was just like a heaviness on my chest and then [I was] really tired," Mueller said.

Her family pushed her to go to the doctor. After several tests, the results shocked her family: she had stage 4 cancer.  

"I had a large mass on my left lung, it has metastasized to my liver, my lymph nodes and my pancreas," she said.

Mueller wasn't a smoker. A doctor suggested she test her home for radon. 

What is considered a high level of radon? 

"When a radon level is at or above 4 [picocuries per liter, or pCi/L], we highly recommend installing a radon mitigation system," said Tranter.

Mueller said her home's radon level tested over 30 pCi/L, well past the danger threshold. Her family quickly had a radon mitigation system installed. A pipe starts under the foundation and extends upward and eventually outside of the house, while a fan draws air through it.

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"It's like a giant straw through your house that's redirecting the radon outside," said Tranter. "So instead of coming into your home, the soil gases including radon go outside."

Mueller says treatment that was still in testing phases back in 2013 was key to keeping her alive and her cancer at bay. Her initial diagnosis was less than six months. Ten years later, she's managing the disease and is simply glad to still be with her family.

"All of a sudden it's like you just want to tell everybody go, you know, go get your house tested," she said.

Tranter showed WCCO a basic three-to-seven-day test kit that's small enough to fit in your hand. It hangs in the lowest part of your home. After a few days, the test is mailed in with the results returning within a few weeks.

Some tests take up to three months to analyze the air, giving homeowners a long-term view of radon's levels in their homes.

"Radon is something we can test for accurately, we can fix it effectively," said Tranter.

Some homeowners assume their house is safe because it's a new build or their neighbor's homes were tested for radon and had low levels. Tranter said those are common misconceptions that could to problems.

Click here for more information about radon and testing.

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