Is Radon Lurking in Your Granite Countertop?

As the popularity of granite countertops has grown in the last decade, demand for them has increased tenfold according to the Marble Institute of America (MIA), a trade group representing granite fabricators.  With increased sales volume and variety, there have also been more reports of “hot” or potentially hazardous countertops, particularly among the more exotic and striated varieties from Brazil and Namibia.  But is this health threat an urban legend or a real danger to a homeowner’s health?

Allegations that granite countertops may emit dangerous levels of radon and radiation have been raised periodically over the past decade, mostly by makers and distributors of competing countertop materials such as the Zodiaq® Quartz product from Dupont™.  The MIA has said such claims are baseless because although granite is known to contain uranium and other radioactive materials like thorium and potassium, the amounts in countertops are not enough to pose a health threat.  Health physicists and radiation experts agree that most granite countertops emit radiation and radon at extremely low levels and pose no health risk.  They say these emissions are insignificant compared with so-called background radiation that is constantly raining down from outer space or seeping up from the earth’s crust, not to mention emanating from manmade sources like X-rays, luminous watches and smoke detectors (yes – even that little “tweeting” device on your ceiling that can save your life can apparently be a peril).

So what’s a homeowner to do?  Like most situations in life, don’t panic.  Get all the facts and then make a decision that is right for you and your family.

Let’s start with what we do know.  The Environmental Protection Agency (EPA) recommends taking action if radon gas levels in a home exceeds 4 picocuries per liter of air (a measure of radioactive emission).  Radon is the second leading cause of lung cancer after smoking and is considered especially dangerous to smokers, whose lungs are already compromised.  Children and developing fetuses are vulnerable to radiation, which can cause other forms of cancer.

Well, where do granite countertops fit into this picture and how much do they contribute to this picocuries per liter ‘thingy’?  The MIA published a report entitled Assessing Exposure and Radiation from Granite Countertops in November 2008, which examined 400 samples from 115 types of granite and 39 different countertops from 27 granite types examined on a full slab basis.  Tests were done with a Geiger (GM) counter, gamma ray meter and Micro Rem survey meter.  Their conclusion:

Environmental Health & Engineering, Inc. has completed a detailed evaluation of potential human health risks of naturally occurring radioactive materials in granite countertops.  The extensive measurements and rigorous mathematical modeling conducted to date indicate that (i) external doses of ionizing radiation emitted from granite countertops are well below levels that would pose a health concern and (ii) contributions from granite countertops to radon levels in homes are lower than background levels of radon exposure typically found outdoors and indoors. ¹

Still feeling a bit queasy about that beautiful piece of New Venetian Gold in your kitchen?  Have it tested.  Contact the American Association of Radon Scientists and Technologists to find a certified technician to determine whether radiation or radon is emanating from a granite countertop.  Testing can cost as much as $400.  You can also find information on certified technicians and do-it-yourself radon testing kits from the Environmental Protection Agency’s web site, as well as from state or regional indoor air environment offices.  Test kits for radon, not radiation, cost $20 to $30 and can be found in most hardware stores or online.

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¹  Environmental Health & Engineering, Inc. Assessing Exposure to Radon and Radiation from Granite Countertops. Rep. Marble Institute of America, 21 Nov. 2008. Web. 12 Sept. 2009. http://www.marble-institute.com/industryresources/assessingexposurereport.pdf.

Related articles of interest:

• Radon levels and public health (medicineandtechnology.com)
• Radon Levels in Your Home (medicineandtechnology.com)