Granite Countertop Radon Information from LIVESTRONG
Mineral crystals form the colors, mottling and striations that make granite an attractive choice for countertops, but those crystals can contain radioactive elements like uranium. Over time, uranium breaks down into a gas called radon. Radon is radioactive and you can't detect it by sight, smell or taste, which leaves consumers wondering about the safety of granite countertops.
Radon exposure is the leading cause of lung cancer in non-smokers, and the second leading cause among the overall population, according to the Environmental Protection Agency. Though the risk is proportionate to radon concentration and how long you're exposed, even low concentrations increase your chances of developing lung cancer. The World Health Organization reports that in cases of radon-induced lung cancer, more than one-half result from low to medium exposure concentrations.
Action levels refer to radon concentrations exceeding the maximum accepted indoor levels. The EPA recommends contacting a radon professional for additional testing and diagnosis when home radon levels reach 4 picocuries per liter of air, or pCi/L. In its 2009 Handbook on Indoor Radon, the World Health Organization lowered its recommended action level to 100 Becquerels per cubic meter, or 2.7 pCi/L.
Test the radon levels in your home by contacting a licensed professional, or by using a short or long-term home testing kit. Short-term tests last from two to 90 days. Long-term tests last more than 90 days. Home testing kits measure the radon concentration in the air, rather than the amount of radon emanating from your granite countertop.
Test in the lowest livable level of your home and in the room containing your granite countertop. If your home has only one usable level, test in two rooms. Place your test devices at least 20 inches away from the granite countertop and above the floor, as recommended by the American Association of Radon Scientists and Technologists.
Though some granite countertops emit more radon than others, the radon concentration in the air provides a more accurate assessment of risk than countertop testing, according to American Association of Radon Scientists and Technologists. Radon levels vary across a countertop's surface, and those levels don't account for ventilation or the room's total volume.
Since radiation levels in natural stone vary, granite countertops may contribute to indoor radon levels, but not significantly in most cases. Radon in the soil beneath your home presents a far greater health risk than your granite countertops, according to the EPA. In an official position statement on granite countertops and radon gas, the American Association of Radon Scientists and Technologists concurs.