Estimates of radon risks across Oregon underscore the need for homeowners to test for the presence of the odorless, invisible radioactive gas, researchers say.
The update, releasedin January, suggests that one in every four houses in the Portland area accumulates radon above the level the U.S. Environmental Protection Agency says should prompt fixes to keep the gas outdoors.
That’s double the national average, said Scott Burns, aPortland State Universitygeology professor who worked with five students to compile radon tests from homes and businesses statewide.
Radon is the second leading cause of lung cancer in the United States after smoking, EPA estimates, and the leading cause among non-smokers.
It seeps from the ground through construction joints and cracks and gaps in foundations, accumulating in buildings. Risk in the Portland area is higher because granite-infused sediment, relatively high in uranium, washed into the region from the torrentialMissoula Floods during the last ice age. Radon is a byproduct of uranium’s breakdown.
Widely available short-term measurement devices cost roughly $35 with lab fees, and contractors say fixes generally range from $1,000 to $2,100.
“It’s a geological hazard that can be dealt with cheaply,” Burns said. “We need to reduce the amount of radiation in our lives, and this is one way of doing that.”
Results and risks
The new results, the first update since 2003, drew on testing in 33,000 homes in the Portland area — 10 times more than the last round. The data cover more ZIP codes, and indicate higher risks.
Long-term tests show ZIP codes with high or moderate average levels of radon at 79 percent, up from 65 percent at last count. PSU’s data crunching includes a list of results by Zip code for the Portland area.
Results confirm high levels in areas of Portland already known to be at most risk, including Alameda Ridge in Northeast Portland.
The expanded data also showed high levels in areas previously unreported, including sections of Banks, Boring, Clackamas, Gladstone, Lake Oswego, Newberg, Sandy, Sauvie Island, Sherwood and Wilsonville.
Radon is responsible for about 21,000 lung cancer deaths every year, EPA estimates, roughly 18,000 of them smokers whose risks are amplified by radon exposure. About 3,000 people who never smoked die annually from radon exposure.
EPA estimates 62 smokers out of 1,000 could get lung cancer from radon if exposed over a lifetime to 4 picocuries per liter of radon, EPA’s recommended “action level.”
Most would not die from radon exposure if they hadn’t smoked, the agency says, and quitting smoking is by far the best way to reduce lung cancer risk.
Seven of a thousand non-smokers could get lung cancer at the same exposure level, the agency says, about the lifetime risk of dying in a car crash.
Mike Brennan, a radiation health physicist with the Washington State Department of Health, said national and international health groups agree that radon is a legitimate health risk.
“We don’t want people to panic, but we want them to be informed,” he said. “It’s a health risk that is easy to reduce, by testing and mitigating if necessary.”
Radon levels tend to be highest in winter, the best time for testing. Exposure is typically greatest in basements and other rooms below grade.
But two houses right next to each other can have sharply different results, Brennan said, even in “low risk” ZIP codes. That’s why health officials recommend radon tests for all homes.
“The tests are not difficult,” Brennan said, “and if you find out you don’t have a problem, you’ve bought some very reasonably priced peace of mind.”
If there is a problem? “My father had lung cancer,” Brennan said. “Let me assure you that whatever you have to do to your house that decreases that chance is cheap.”
“Really, really scary”
Kate Mytron decided to test for radon after her house-hunting friends reported seeing radon venting pipes outside many of the homes they were exploring.
Mytron, who lives in a 100-year-old house in Southeast Portland’s Lents neighborhood, mailed in a short-term testing device. The results showed radon levels of 88 picocuries per liter in her basement, 22 times EPA’s action level.
“I just looked at it and thought, ‘I must be reading it wrong,'” said Mytron, an executive assistant at Freightliner. “It was really, really scary.”
Mytron’s basement has a finished slab and an unfinished crawl space. EcoTech, her contractor, sealed the floor of the crawl space with a membrane and punched a small hole in the basement floor.
Then workers ran plastic pipe from the hole and another sealed suction point beneath the crawl space to an inline exhaust fan mounted outside the house. From the fan, the pipe continues through the roof, where radon can dissipate into the air.
The venting system is designed to capture radon before it gets into the house. After Mytron’s $1,500 of work, her radon reading dropped to 1 picocurie per liter.
EPA recommends doing a second short-term test if readings are 8 picocuries are higher. For readings below 8 picocuries, it recommends following up with a long-term test of 3 months or more.
If the tests average 4 picocuries or higher, you should fix your home, EPA says. Between 2 and 4 picocuries, you should consider repairs.
Don Francis, EcoTech’s general manager, said his firm completes about 300 radon fixes a year, competing with nine other certified radon mitigation contractors serving the Portland area.
More home buyers are conducting tests as part of home inspections, Francis said, the largest source of the work. Sealing gaps helps some, but sealing plus venting is the surest fix.
Francis warned that Oregon doesn’t regulate installation of radon vents. Most cities and counties require a mechanical permit, but some contractors skip it. Fans should be mounted outdoors, not indoors, he said.
The fan’s suction will also draw heat from the home if the contractor doesn’t seal the ground in the crawl space or holes in the basement floor, Francis said, lowering the installation bid but boosting utility bills.