Does the EPA believe there is a danger of radon gas or associated radiation being emitted from granite countertops?
It is possible for any granite sample to contain varying concentrations of uranium and other naturally occurring radioactive elements. These elements can emit radiation and produce radon gas, a source of alpha and beta particles and gamma rays. Some granite used for countertops may contribute variably to indoor radon levels. Some types of granite may emit gamma radiation above typical background levels. However, at this time EPA believes that the existing data is insufficient to conclude that the types of granite commonly used in countertops are significantly increasing indoor radon levels. While radiation levels are not typically high, measurement of specific samples may reveal higher than expected levels on a case-by-case basis. Granite is a naturally occurring igneous rock, meaning that it was formed by the cooling of molten rock. It is quarried and processed to produce commercial products such as countertops.
What advice does the EPA have about radon for consumers who have granite countertops?
EPA believes the principal source of radon in homes is from the soil in contact with basement floors and walls. To reduce the radon risk you should first test the air in your home to determine the radon level. There are many do-it-yourself radon test kits available through retail outlets and on-line, starting at about 25. While natural rocks such as granite may emit radiation and radon gas, the levels attributable to such sources are not typically high.
If your home has a radon level of 4 picocuries per liter (pCi/L) of air or more, you should take steps to fix your home and reduce the radon level. Contact your state radon office (www.epa.gov/radon/whereyoulive.html) for assistance. Hire a qualified radon professional (www.epa.gov/radon/radontest.html) to fix or mitigate your home. The key to reducing your risk of lung cancer from radon is to test your home and mitigate when necessary. A specially-trained and qualified radiation professional may be equipped to test for other radon sources (such as granite or diffusion from drinking water) when diagnosing the nature and source of your home's radon problem.
Can I test my granite countertops for radiation or radon?
At this time, a generally accepted radiation testing protocol for countertops does not exist, and neither imported nor domestic granite products require radiation testing.
Radiation concentrations can only be measured using sophisticated portable instruments, or with laboratory equipment. These instruments and equipment require a knowledgeable and trained user and proper instrument calibration. For information about local radiation experts, the Conference of Radiation Control Program Directors (CRCPD) maintains a web page where you can find contact information for each state's radiation protection program - www.crcpd.org/Map/map.html
Although not specifically designed or intended for measuring radon emissions from countertops, do-it-yourself test kits are available through retail outlets and on-line, starting at about $25. If you are concerned about the radon level in your home, purchase a test kit and use as instructed. To learn more, visit www.epa.gov/radon or read A Citizen's Guide to radon at www.epa.gov/radon/pubs/citguide.html.
Are the levels of radon gas and radiation emissions from granite countertops dangerous to humans or animals?
While radon gas and radiation emission levels attributable to granite are not typically high, there are simply too many variables to generalize about the potential health risks inside a particular home that has granite countertops. It is prudent to limit your family's exposure to radon whenever possible. Commonly employed mitigation techniques can reduce the radon level coming from soil beneath your home to 2 pCi/L or less in most homes. At EPA's action level of 4 pCi/L, a smoker's risk of lung cancer is about five times the risk of dying in an auto accident, and if you've never smoked equal to the risk of dying in an auto accident. The U.S. Surgeon General and EPA strongly recommend that all homes be tested for radon.
Has EPA done studies on radon gas and radiation emissions from granite countertops?
We are aware of a few studies that have conducted limited research on radon in granite countertops. EPA will continue to review this research. However, there are many studies proving the link between radon in indoor air and lung cancer, including EPA's 2003 risk assessment - www.epa.gov/radon/risk_assessment.html
Does the EPA have plans to conduct a study of granite countertops?
EPA will continue to monitor and analyze the evolving research on radiation and granite countertops and will update its recommendations as appropriate. There are currently no regulations concerning granite countertops radon gas or radiation emissions.
"Position Statement: Granite Countertops and Radon Gas," Science and Technical Committee of the American Association of Radon Scientists and Technologists (AARST), August 4, 2008, 2 pages. Click here for PDF version