Every day we breathe in a radioactive, cancer-causing gas.  Usually it is in small doses that aren't dangerous, but radon is found at unhealthy levels inside one out of every 15 homes.

The feds blame it for the deaths of 21,000 Americans each year.

Central Virginia Radon Specialist Wolfgang Hermann sets up his tripod tester to track the radon readings in an Albemarle County home.  A safe level tops out at four.

"You can't smell it.  You can't see it," said Hermann.  "There's no way other than testing." 

The cancer-causing gas drifts through the air naturally in small doses.  The radioactive byproduct of uranium rises into homes from the rocks and soils, especially Virginia's granite and shale.

Ryan Paris is the state's indoor radon program coordinator.  He said, "We have more high-risk counties than moderate or low."

Radon results from private testing company Airchek show those varying levels.

In central Virginia, 23 percent of tested homes in Charlottesville and Albemarle had high radon readings.  That drops to 16 percent in Greene, 20 in Fluvanna, and 22 in Orange.  But it goes up to 35 percent of tested homes in Louisa.

The radon risk rises dramatically in the valley - with 43 percent of homes in Augusta County, 54 percent in Staunton, and 52 percent in Waynesboro recording high radon levels.

Paris said, "You can get radically different results from houses on the same street.  It can be that localized."

Long-term exposure to excess radon is a health hazard.  The feds label the gas second only to smoking for causing lung cancer.

"It's not energetic enough to penetrate your skin," said Paris.  "It doesn't cause any problem from outside.  But if you inhale it, that large particle can do a lot of damage to the interior of your lung tissue."

Radon peaks in winter months when your house is shut up.  Paris stated, "Homes - to be energy efficient - are becoming tighter.  And, that can cause radon to be a bigger problem, because it can't naturally disperse and get out of the home."

That's why we go back to Hermann.  He said, "It's my job now to bring the radon level down."

The tester is also a radon reduction specialist.  He searches for the source and marks the spot where the gas seeps in.  Hermann stated, "Under the slab it accumulates there. So we drill through the slab."

Hermann drills down through the home's foundation, and begins installing this radon mitigation system.  He said, "We draw air through the opening, into a pipe, through a pipe system and that runs outside to the roof line and beyond."

The entire fix to reduce radon levels in a home typically only takes a day, but it can make a big difference in the quality of the air you breathe.  Hermann stated, "Every house can be mitigated. Every house."

The state's expert recommends testing your home in the spring or fall - when it's not all shut up - to get an accurate reading of radon levels.  Do-it-yourself kits sell for as little as $12.