The second leading cause of lung cancer could be lurking in your home without you knowing it.
Radon is a naturally occurring gas that can enter homes through foundation cracks or openings. It's invisible and odorless. High concentrations can cause health problems.
"It's pretty hazardous and we don't even know it's there," said Kathy Glapa with the Tennessee Department of Environment and Conservation.
Two state agencies, the federal government and the American Lung Association are encouraging Tennesseans to test their homes for radon.
Bill Gunther, President of BJK Property Inspections, Inc., told Nashville's News 2 radon can accumulate in both new and old homes and just because your neighbor's home doesn't have elevated levels doesn't mean you're in the clear.
"I had a house with a level of 8.8 and the neighbor's house had a level of 1.3," Gunther told Nashville's News 2.
According to Gunther, approximately 20% of the homes he tests have elevated levels of radon.
So what do you do about it?
"You get it fixed like anything else," said Gunther.
A radon mitigation system can run several hundreds of dollars to a couple of thousand dollars.
"When you think of just putting a ventilation system in to save your life, it is well worth it," said Gunther.