Radon and radiation exposure from stone and solid surface countertops in indoor applications

To learn more about radon and radiation, click here for FAQs and click here for Resources.

BuildClean is concerned about recent laboratory radon testing of popular consumer colors of commercial/residential granite. The U.S. Environmental Protection Agency (EPA) has set an "action" guideline level for radon exposure at 4 picocuries per liter of air (pCi/L - the common measurement for radon levels in the atmosphere). However, that does not mean that potential health risks do not exist at lower levels of exposure. Recent scientific studies have indicated that some granites may emit as much as 735 picocuries per square foot* (pCi/sqft - a measurement of radon emanation). To learn more about what the EPA says on radon and indoor granite applications, click here.

In addition to radon emanation, some granites may also emit varying levels of radioactivity as a result of presence of the radioactive elements potassium (K), thorium (Th) and uranium (U) - all naturally occurring in the stone.

During the 1990s, the concern about the emanation of radon and radiation from granite was raised and immediately and effectively quashed by the Marble Institute of America (MIA), a trade association for the stone industry. What's missing here? The answer: consumer and industry recognition that natural stone building materials -- when utilized in closed, indoor environments -- should be the subject of extensive research to determine if the same natural rock (granite and other stone) that has been known for years to endanger human health in certain regions of the United States because its inherent chemistry emanates radon and radiation is possibly unsafe when used in such indoor applications as countertops, wall treatments and floors. It's certainly worth the effort. In 2005, the U.S. Surgeon General issued a health advisory specifically warning that indoor radon is the second-leading cause of lung cancer and the EPA has said that radiation exposure can increase the risk of cancer and gene mutation. Why would we not ensure that increasingly popular building products are healthy and safe?

*Results from these studies are reported in pCi/sq ft, which is the measure of radon emanation from the mass of the stone. The amount of radon gas in a room resulting from that emanation (pCi/L) will vary depending upon the amount of stone in the room (measured in square feet), the size of the room and the amount of fresh-air circulation.