The concern that granite countertops may cause lung cancer stems from the natural occurrence of uranium and other radioactive material in stone. The normal decay of uranium releases radon gas which is the second-leading cause of lung cancer and the leading cause of lung cancer in nonsmokers.
Most radon exposure occurs due to radon that seeps into our homes through the foundation. Studies have shown that granite countertops can emit radon and radiation, but this is usually at very low levels that are well below the level occurring in most homes, and well below the limit recommended by the Environmental Protection Agency (EPA). In some cases, however, the radon emitted from granite countertops has been significant.
According to the EPA, the most important step is to first test your home for radon. Do-it-yourself radon test kits are available for $25 or less at most hardware stores. If your levels are abnormal (greater than 4 pCi/L), having the problem repaired (radon mitigation) by a certified professional can usually lower your level to an acceptable number.
If you wish to get an idea on your own if your granite countertops are of concern, you might consider doing one radon test in the lowest level of your home, and another in the room where you have a granite countertop. (And perhaps a 3rd test in a room at a distance but on the same floor as your granite countertop.) If you try this, it is recommended that you place both kits at least 20 inches off the floor, and at least 20 inches away from the granite countertop. If the levels are abnormal, retest both areas to get a second reading.
Even if your granite countertops are emitting a significant amount of radon, this does not necessarily mean they need to be removed. Ventilation techniques to improve indoor air might lower the radon level to acceptable levels.
If you are still concerned that your granite countertops may be raising the radon level in your home after mitigation, there are a few options. The EPA suggests that you may hire a certified radon professional to test for other sources of radon in your home such as granite countertops. The American Association of Radon Scientists and Technologists has a list of qualified professionals.
Currently, no regulations require manufacturers to test for the presence of radon in building materials. But this may change in the future as we learn more.
- Radon and Lung Cancer – What Everyone Should Know
- Radon Testing - How to Test Your Home for Radon
- Radon Mitigation - Getting Rid of Radon in Your Home
Allen, J. et al. Assessing exposure to granite countertops--Part 2: Radon. Journal of Exposure Science and Environmental Epidemiology. 2010. 20(3):263-72.
Environmental Protection Agency. Granite Countertops and Radiation. Updated 07/11/11. http://www.epa.gov/radiation/tenorm/granite-countertops.html
Position Statement. Granite Countertops and Radon Gas. From the Science and Technical Committee of the American Association of Radon Scientist and Technologists (AARST). August 4, 2008. http://www.aarst.org/images/AARST_Granite_Postition_Statement_8-04-2008.pdf.