Andrew Gilbert wants Minnesotans to test for radon.

A colorless, odorless and radioactive gas that comes from soil, radon is the leading cause of lung cancer among non-smokers in the United States, according to the Minnesota Department of Health.

“We need to stress that this is a persistent health risk in Minnesota,” said Gilbert, a radon program specialist at the MDH.

Minnesota and several other states require homes to have working carbon monoxide detectors, but most states don’t mandate radon testing.

“Ironically, the risk from dying from radon that you are exposed to in the home is about 70 times greater than dying from carbon monoxide exposure in the home,” said Bill Angell, a University of Minnesota professor who has studied indoor air quality and radon extensively.

The MDH estimates one in three Minnesota homes has radon levels that pose a severe health risk for people over many years of exposure, and experts say testing is needed.

In 2009, the state passed a law requiring that all single-family homes be built with basic radon-resistant techniques, but the law doesn’t apply to apartments or dorms.

Typically, only first-level apartment units are at a high risk for radon exposure, Gilbert said.

According to Minneapolis planning department data, only one new single-family home has been built in the University area since the law has taken effect.

Several area landlords declined to comment for this story.

In Maine, a 2009 law required all rental properties to be tested for radon once every 10 years, but the law doesn’t go into effect until March 2014.

“Radon in rental housing can be a little tricky,” Gilbert said. “People who are living in the rental units and are exposed to the gas are not the ones who have the final say of whether they mitigate it.”

Minnesota residents can purchase radon testing kits from the city for $9.

Speech-language-hearing sciences senior Maddie Graves rents an apartment in St. Paul and said she’d like to see landlords test for radon.

“Am I going to get upset at my landlord for not testing for radon? No,” Graves said. “But I think for the good of the people who are paying rent, it would be a good idea.”

In Minnesota, soil conditions cause radon to be an especially large problem.

Angell said cold weather during the winter also contributes to high radon levels in Minnesota homes.

“We are in a cold climate, so we heat our homes,” said Angell. “That creates a suction for the gas and brings radon into our homes.”

At the University, though there are no regularly scheduled tests for radon, the University’s radiation safety officer, Brian Vetter, said the school did an extensive study on its campuses in the ’90s as part of a state initiative.

“Since we didn’t see any high levels in the University buildings, no mitigation was necessary at that time, but if people have requests, then we would test,” he said.

Vetter said in addition to past testing in University buildings, the school is currently testing for radon in underground campus utility tunnels to ensure levels are at acceptable conditions for workers.

To raise awareness about the radioactive gas, in 2012 Gov. Mark Dayton named January “Radon Action Month” in Minnesota. In both 2012 and 2013, the city of Minneapolis gave away free radon-testing kits.

Eliza Schell, the city’s healthy homes grant manager, said in 2013 the city distributed about 400 radon testing kits during January, an increase from about 150 in 2012.

In 2012, MDH put up more than 50 posters in the skyway systems in St. Paul, Minneapolis, Duluth and Rochester to increase awareness.

“If you live in Minnesota,” Gilbert said, “then you should know what radon is, and you should know how to protect yourself.”