BOZEMAN, Mont. -

Does your home have radon? If you don't know, you might want to find out.

January is National Radon Action Month.

Dustin Schreiner with the Gallatin City County Health Department explained that radon is a colorless, odorless gas, and anyone exposed to it long term can die.

"When you breathe in this gas, it decays in your lungs," Schreiner said. "It can actually cause breaks in the DNA which can lead to cancers."

He said the gas comes from the natural breakdown of uranium in soil and filters into the air.

It can drift into any type of building through cracks and holes in the foundation, and it can build it up once it gets trapped inside.

The Environmental Protection Agency said people are most at risk in their home where they spend most of their time.

"The biggest risk with radon is long term exposure at high levels," said Don Dickson, owner of RRR Mitigation, a company dedicated to removing radon from houses.

"We pipe the radon out from underneath the house in the crawl space before it has a chance to rise up and get into the air space where you'd actually be breathing in," he said.

Why do homeowners need to get rid of radon?

According to the Surgeon General, radon is the second leading cause of lung cancer in the United States, behind smoking.

The EPA states radon is responsible for 21,000 lung cancer deaths in the United States each year.

That's seven times more deaths than the third leading cause, second hand smoke, which causes around 3,000 deaths.

How do you know if your home has radon? Tests measure levels in picocuries per liter of air or pCi/L's.

"If you find that your levels are about 4 pCi/L's that is the mark that the EPA designates for mitigation," explained Erron Dawson, with RRR Mitigation.

Schreiner explained they've seen levels of more than 100 in Bozeman.

"The longer you're exposed to it and the higher levels you're exposed to, it increases your cancer risk," he said.

That's why he recommends homeowners mitigate their homes sooner rather than later.

The Environmental Protection Agency estimates that 1 in 15 homes in the United States has elevated radon levels.

You can buy testing kits at the Gallatin City County Health Department.

New homes can be built with radon resistant features, but we're told they should still be tested.