It's odorless, tasteless and invisible, but kills thousands of people each year. Radon, a poisonous and naturally occurring gas, is the leading cause of lung cancer among nonsmokers, and state officials and radon experts say Blaine County residents are especially at risk.
"Basically, one out of two homes you drive by have high radon levels," said Jim Faust, project manager for the Idaho Department of Health and Welfare. "We don't know if you're going to get lung cancer, but we know what the end result could be."
Radon is a radioactive gas produced when naturally occurring uranium in soil breaks down. It's is the second-leading cause of lung cancer in the nation, and the U.S. Environmental Protection Agency estimates that it causes 21,000 lung cancer deaths per year.
"It's not nearly as dangerous as tobacco use," said Michael Walsh, owner of Sun Valley Home Inspectors. "If it's a second home that isn't visited that often, the concern would be less. But if it's a home you're in long term and raising children, the concern would be higher."
The EPA estimates that one in 15 homes nationwide has elevated levels of radon, defined as any level above four picocuries per liter (a unit roughly equivalent to parts per million). However, levels are much higher in Blaine County.
"Right now, at least 60 percent of the homes I test are over [that level]," said Gordon Gammel, owner of Idaho Testing Geologic in Ketchum.
Gammel said the average level in Blaine County is between eight and 10 picocuries per liter, but he's seen levels as high as 200 over his 30 years of testing.
"The levels are sporadic by location," he said, as levels depend on the amount of uranium in the granite underneath a home. "You will find pockets of high levels, but there is actually a great level of variation from home to home."
The Idaho Department of Health and Welfare places the average radon level for homes in Hailey and Ketchum at about 9.6 picocuries per liter. In Ketchum, 61 percent of the 536 homes tested returned positive for elevated levels, with the highest level coming in at 222 picocuries per liter—more than 55 times the acceptable level.
The amount of snow and ice on the ground could put Blaine County residents at special risk.
During the summer, radon escapes the soil and dissipates harmlessly into the air. When the ground freezes and snow accumulates, radon is trapped in the soil with the only escape being through cracks and crevices in a home's foundation.
"Homes actually suck air out of the ground," Faust said.
In the summer, radon levels in homes can be lower due to open windows and better ventilation. That's why homeowners should test in the winter, giving what Gammel calls a "worst-case scenario."
Testing can be conducted by a professional such as Gammel or Walsh for roughly $100, depending on the home, but home test kits are available for $5.95 on www.radonidaho.org.
"People say, 'I've lived in this house for 20 years. What the heck, what you can't see can't hurt you,'" Faust said. "If it was purple, everyone would test."
Gammel said most people don't encounter a radon test until they go to sell their homes and prospective buyers hire an inspector.
"The cruel irony is, the homeowner usually ends up paying for it [by] lowering their price," he said. "They might as well have fixed it earlier and enjoyed the clean air."
Luckily, Walsh said, fixing a radon level is not terribly difficult.
"Anyone that's handy can do the work as long as they obtain the EPA protocols," he said.
Most systems involve a pipe installed under the home's slab foundation or in a crawl space and venting to the outside. Perforations allow radon to get inside the pipe and plastic sheeting traps the radon there, where it is pushed out of the house by fans.
Gammel said a professional installation can run from $1 to $2 per square foot of the house, depending on the home's foundation. He and Faust recommend retesting the home once snow is on the ground to make sure the system is working properly.
With cancer risks and real estate prices at stake, Walsh said, he's stunned at the number of people he encounters who have never conducted a radon test of their homes.
"They think ignorance is bliss, but this is a real threat," he said. "It's important to know what you're living with."
Katherine Wutz: email@example.com
Need more info?
The EPA's "A Citizen's Guide to Radon" is available at http://www.epa.gov/radon www.epa.gov/radon. Information is also available at www.radoidaho.org.