GREEN BAY, WI --Radioactive kitchen counters. A colorless, odorless, tasteless gas is coming out of your granite counter top. It's called radon and it's the second leading cause of lung cancer after smoking. So how much is in your kitchen? And is it enough to be dangerous?
All granite naturally contains some radon because it's a stone mined from the earth. But how much depends. In a few cases, radon specialists say a counter top could emit enough of the gas to equal smoking half a pack of cigarettes a day.
"This particular test was done on a granite counter top in De Pere, Wisconsin," said owner and radon expert with Bayside Inspections, Ron Nohre. Nohre says it's not often he gets a call about radon in counter tops. But when he does, he tests for it.
"My high level was 1.8 my low level was 0.0," said Nohre.
It turns out that granite counter top was safe. Radon levels are measured in picocuries per liter of air. The Environmental Protection Agency recommends taking action, and removing the granite, if levels are at 4 or higher inside a home.
But we talked to one expert who says in some rare cases, granite can emit dangerously high levels.
"We found extremely high levels. As much as 100 picocuries per liter," said Stanley Liebert, a quality assurance director at CMT Laboratories in New York. He's tested nearly five hundred homes for radon in granite counter-tops, and says less than ten percent showed high levels. But those that do, Liebert says can be a real concern.
"There is no question that granite needed to be removed and replaced with something that was not radioactive," said Liebert.
The Marble Institute of America posted independent scientific research about the issue on their website. Researchers tested 1 million granite counter tops, taking into account the likelihood the stone would be purchased, the size of the counter top installed, the size of the home and ventilation rate of the home.
The results, 99.95 percent produced radon levels lower than the normal level outdoors. In other words an "extremely low probability."
Local granite retailers, like Ryan Strenn, at Bay Area Granite and Marble in Suamico, says how much radon a stone emits depends on where in the world it is quarried from, and what part of the quarry it is mined from.
"There may be a pocket in the quarry which may have a bit higher levels of uranium," said Strenn.
Granite from Brazil or India, some of the main granite exporters, tend to have higher levels according to Liebert. Also, granite with a purplish or magenta coloration. But Strenn says all evidence points to only a minute chance of dangerous amounts of radon in granite.
"I do have it in my house, I have a three year old daughter. If at all I thought it was going to harm her I wouldn't have it at all," said Strenn.
Local expert Ron Nohre says based on his experience, granite is safe.
"Would I be afraid of granite in my personal home? Absolutely not," said Nohre.
Radon experts and granite salesmen alike say if you have doubts, get your counter tops tested.
The radon levels emitted from your basement should be higher than any levels emitted in your kitchen. New homes, built tighter and more energy efficient, will also tend to have higher levels of radon than older homes.