Granite countertops: Hotter than you think

Add this to the list of potential health risks once declared "ludicrous" that may actually have merit. From the New York Times:

The EPA recommends taking action if radon gas levels in the home exceeds 4 picocuries per liter of air (a measure of radioactive emission); about the same risk for cancer as smoking a half a pack of cigarettes per day. In Dr. Sugarman's kitchen, the readings were 100 picocuries per liter. In her basement, where radon readings are expected to be higher because the gas usually seeps into homes from decaying uranium underground, the readings were 6 picocuries per liter. [Link]
The source? Granite countertops, which contain uranium at varying levels depending on where it was quarried.
A granite countertop that emits an extremely high level of radiation, as a small number of commercially available samples have in recent tests, could conceivably expose body parts that were in close proximity to it for two hours a day to a localized dose of 100 millirem over just a few months.
That's about the amount someone living near a nuclear reactor might get in a full year.
William J. Llope, a professor of physics at Rice [University], said his preliminary results show that of the 55 samples he has collected from nearby fabricators and wholesalers, all of which emit radiation at higher-than-background levels, a handful have tested at levels 100 times or more above background [radiation levels].
Home radon testing typically runs from $100 to $300. Industry reps continue to dispute the findings, noting the proximity and duration of exposure required for such levels of exposure. The article doesn't address the way your garden-fresh produce would be irradiated by sitting on those gorgeous granite counters, however, which you then ingest.

Our fantasy kitchen redesign would use countertops made of recycled glass, which has great color options and is a more sustainable option than granite.


tjovand said...

We understand why homeowners would be alarmed by this New York Times article, but the Marble Institute of America would like to assure people that research shows granite countertops pose no threat. The U.S. Environmental Protection Agency, Consumer Reports and repeated independent studies have shown granite countertops pose no health hazard.
• EPA stated Friday: “EPA has no reliable data to conclude that types of granite used in countertops are significantly increasing indoor radon levels.” (http://iaq.custhelp.com/cgibin/iaq.cfg/php/enduser/std_alp.php)
• University of Akron researchers found no threat. (www.marble-institute.com/industryresources/radontesting_u-akron2008.pdf
• An independent scientific analysis of a variety of studies shows that, accounting for normal airflow in the typical home, radon contributed by granite countertops ranges from 0.01 – 0.02 pCi/L – levels that are 200 to 400 times lower than the EPA guideline of 4 pCi/L.

By some measures, the amount of radon emitted by a granite countertop is less than one millionth of that already present in household air from other sources. Many granite countertops do not emit radon at all, and those treated with sealant reduce emissions even further.

Tiffany Daniels
Cohn & Wolfe on behalf of the Marble Institute of America