Can a granite countertop in the kitchen be a potential cause of lung cancer by giving off dangerously high levels of radon gas?
The New York Times created a stir and triggered alarm recently when it reported a granite kitchen counter in an upper-New York state woman's home was found to emit radiation at 10 times the level found elsewhere in her house.
She had the countertop ripped out. It was tested and found to contain high levels of uranium, which releases radon gas as it decays.
The U.S. Environmental Protection Agency was later asked whether there is a danger of radon gas or radiation being emitted from granite countertops.
The U.S. government agency's reply: "Some granite used for countertops may contribute variably to indoor radon levels. At this time, however, EPA does not believe sufficient data exist to conclude that the types of granite commonly used in counter tops are significantly increasing indoor radon levels."
The EPA said some granite may emit gamma radiation above typical background levels. "While radiation levels are not typically high, measurement of specific examples may reveal higher than expected levels on a case-by-case basis."
Ottawa residents Greg Osborne and Laura Wardlaw heard about the New York Times article from a friend, who knew they would be interested since they had recently spent close to $6,000 for granite countertops in their west-end home.
"I suspect the biggest health risk is the psychological and resulting physiological impact of reading and keeping current with all the possible health impacts in our lives," says Wardlaw.
Still, the consensus is that this couple--and anyone concerned about possibly high radon levels in their home--should have the home tested for the gas.
"Exposure to high levels of radon increases the risk of developing lung cancer," according to Health Canada.
"This relationship has prompted concern that radon levels in some Canadian homes may pose a health risk."
Health Canada's studies show that high radon levels are not widespread in Canadian homes. "However, it is difficult to predict the level in any one home," says the agency.
There has recently been increased awareness in Canada of the dangers of radon. Faced with what Health Canada says was new evidence linking radon to lung cancer, the federal and provincial governments last year drastically lowered the safe level for radon in a home. It is now one-quarter of the level it was previously.
Health Canada's guideline for exposure to radon is now 200 becquerels per cubic metre.
"Because of the very low risk level, Health Canada does not have specific recommendations for possible radiation hazards from granite counter tops," says Health Canada spokesman Philippe Laroche. "We do recommend testing all homes for radon gas, which can arise from a number of sources, particularly from soil gasses seeping into the basement."
Mike White owns HomePro Inspections in Ottawa. His work is mostly doing home inspections for people considering buying a home, but he tests for radon as a sideline. He says he strongly doubts that a granite countertop would ever be the main source of radon in a home.
Radon typically enters a home through the foundations, says White, and it's usually a fairly simple matter to solve the problem by improving the ventilation.
White bought his radon-testing equipment in May, but says that so far he's been hired to do very few of the tests, for which he usually charges $150. Of about 10 tests he has done, all the homes passed Health Canada's new standard. None of the homes had a granite countertop.
"Radon testing can be easily carried out by the homeowner using special detectors available from commercial businesses," says Laroche.
"These devices are simply placed in your home, exposed to indoor air for a specified period of time and then returned to the company to be analyzed. Other businesses will send a trained technician to your home to do the testing for you."
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