Nov 13, 2008 11:00 pm US/Central
Radon In Granite Countertops?
(WCCO)
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Radon is the second leading cause of lung cancer. It's a naturally occurring gas found in rock, soil and water. So it only makes sense you might find it in granite.
CBS
Granite is the rock of choice for many homeowners. It's durable, virtually scratch resistant and never fades, but there's a side of this stone you may not know.
"We found some materials that had radon-generating potential," said Dr. Daniel Steck, a physics professor at St. John's University. Steck heads the Minnesota Radon Project and has been running radon tests for years.
Radon is the second leading cause of lung cancer. It's a naturally occurring gas found in rock, soil and water. So it only makes sense you might find it in granite. Granite, like other kinds of rocks and soils, contains some naturally occurring radioactive elements.
Steck first tested granite for radon in the 1980s. Back then, the stone came from North American quarries and tests showed little or no radon. So Steck was skeptical when new reports surfaced earlier this year claiming researchers were finding more radon in the rock.
"Until I got some samples from one of the granite top manufacturers and measured them," he said. "These days there seems to be much more imported granite present than there was 20 years ago."
This time some of the stone samples came from overseas. He tested stones from Africa and Brazil.
"The stuff, the hot stuff that I have, is about 10 to 50 times hotter than the stuff I measured in '88," he said.
But it didn't all test high. Steck said that's part of the challenge. He said it's impossible to identify radon rich granite by color or even by name since it doesn't all come from the same area and since the radon levels can vary in the exact same slab.
Another problem for consumers is finding out where their granite originated because manufacturers don't have to tell you.
"We don't know how common this material is," said Steck.
"There just hasn't been a lot of testing," said Guido Gliori, president of the Marble Institute of America. Gliori also works at Grazzini Brothers & Co. in Eagan, Minn.
Gliori said granite manufacturers are not required to test the stones, but the Marble Institute of America is currently studying the issue.
"We're testing 135 different types of stone. We're also testing full slabs to get an idea how the small samples we're testing compare to the whole slabs of material," he said.
Those test results are expected back soon.
All of this is enough to make a homeowner wonder if they're being exposed to this harmful gas when they add granite to their homes. Steck said it's more important to measure radon as it mixes with the air in your home, because that's the level you breathe in. The only real way to know that is to test.
So we found five families willing to do just that. All have granite countertops.
"I'd like to know if there's high levels of radon or what level of radon there is," said Jill Sonnesyn, a Plymouth homeowner.
"You would hate to think that something bad would come out of it," said Cindy Siegel, an Eden Prairie homeowner.
"I hadn't heard of granite having issues," said Judy Myers, also a Plymouth homeowner.
On the advice of radon experts, we placed two radon test kits in the kitchen, one in a neighboring room and one in the basement. The idea was to measure the radon in various places throughout their homes to determine if the dangerous gas is coming from the countertops or the most common source -- the basement.
"It'll be interesting to see what the results are," said Sonnesyn.
If a radon test reads four pCi/L (picocuries per liter) or below, the government says you're safe. Anything above four, you may have a problem.
Of the five homes we tested, three tested safe and two tested high. One was Myer's kitchen which tested at just over six.
"When it came back positive on the main level, I was a little concerned," said Myers.
Then she read her basement test which came back even higher than that at 11.6.
Steck said those results mean it's likely the radon gas in Myers' home is seeping in from the basement not from her new granite countertops.
"It's nice to know," she said. "We know where it is coming from and how we can take care of it."
According to the EPA and the Minnesota Department of Health, one in every three homes in Minnesota will test high for radon. Minnesota is in a high risk area. It is why the government recommends all homes be tested for radon. That means people in Minnesota are at higher risk of lung cancer, even if they've never smoked. You can put in a radon mitigation system to get the gas out of your home. It typically costs between $1,000 and $2,000 to add one to an existing home. It can cost as little as $200 to include one in a home under construction.
"We're definitely looking at getting it taken care of," said Myers.
Julie Mosier's Richfield home tested at 4. That's right at the border of what's considered safe. So experts recommend she now do a long term test because the levels of radon can vary depending on the time of year.
And though the countertops in the homes we tested appear safe, Steck said there are still things he hopes granite companies will do.
"I think that the responsible granite companies will come to the position of saying we'll find those pieces that aren't perfectly safe and get them off the market," he said.
As for consumers, he said, "This tells them the need to measure their house for radon, period."
Steck said it hasn't been determined whether sealing granite can keep radon gas from getting out into your home. There are some studies that suggest when granite has a mesh backing on the underneath side the radon does not become exposed. However, researchers are still trying to determine if the radon bounces back up through the other side of the stone.
As for other types of countertops, Steck said most of the other materials are made of crushed quartz which tends not to contain radon.
If you'd like to test your home for radon you can get radon test kits for $7 a piece through AirChek.
(© MMIX, CBS Broadcasting Inc. All Rights Reserved.)
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