Hazardous Countertops

Granite countertops for kitchens and bathrooms have been popular for a very long time. They are durable, easy to clean, and maintain their spotless appearance for years. For many homeowners renovating their homes in Los Angeles, the gold standard for countertops is granite.

In recent months, however, there have been reports from newspapers, radon inspectors, homeowners and specialists suggesting that some granites might be emitting significant levels of radon and radioactivity; in some instances with radiation measurements several times higher than normal background levels. Here's the Houston Chronicle, writing on July 25th about a Rice University physics professor's findings in the Houston area:

"Most stones, in terms of radioactivity, are relatively quiet," Llope said. "But there are a couple I have found that are insanely hot."

Using a Rice University spectrometer, Llope has examined 55 stones, representing about 25 varieties of granite purchased from Houston-area dealers. Some, he said, could expose homeowners to 100 millirems of radiation — the annual exposure limit set by the Department of Energy for visitors to nuclear labs — in just a few months.

The New York Times published an extensive article on this issue, as have CBS and numerous other media sources. Many experts, however, disagree--suggesting that most granite types only emit minute amounts of radiation and radon; the head of the Marble Institute saying:

Repeated studies have found that granite is safe. Unfortunately, some recent junk science being reported as fact only serves to panic the public, not inform it.

Junk science or not, an exposure to 100 millirems of radiation over several months from a kitchen countertop is not trivial: passengers on a flight from Los Angeles to New York are exposed to 3 millirems of cosmic radiation for example. And although it is possible to reduce the radiation exposure simply by standing away from the material, there is no known safe level of radiation or radon, so any exposure should be considered with care.

Bottom Line: it appears that most granites do not emit significant radon or radioactivity, but some apparently do. It is probably best to have granite tested before it is installed or even purchased. Information on certified technicians can be found on the EPA's web site, and radon testing info is provided on the web site of the California Department of Public Health. Additional information on technicians and do-it-yourself radon testing can be found on the web site of the American Association of Radon Scientists and Technologists.