Click here to open a PDF of Dr. Toohey's full letter to the NY Times

The EPA issued its new statements late Friday, following media reports (NY Times article "What's Lurking In Your Countertops?", July 24, 2008) citing junk science and inconsistent testing results that created public concern about granite countertops as a source of radon gas.

"While natural minerals such as granite may occasionally emit radon gas, the levels of radon attributable to such sources are not typically high," the EPA statement said. "EPA believes the principal source of radon in homes is soil gas that is drawn indoors through a natural suction process."

"Granite is a natural mineral formed by earth's geology," the statement continues. "It is mined and used to produce commercial products such as countertops. It is possible for any granite sample to contain varying concentrations of uranium that can produce radon gas. Some granite used in countertops may contribute variably to indoor radon levels. However, EPA has no reliable data to conclude that types of granite used in countertops are significantly increasing indoor radon levels."

Volume IV, Issue 1, March 2007

Is Radiation/Radon in Granite Dangerous?

No. There are two ways in which countertops, tiles, and other finishes made of granite might emit any level of radiation. The first is by release of tiny amounts of the radioactive gas radon which can be breathed in; the second is by direct radiation from the surface itself to the homeowner. In both cases, the radiation emitted is from the same process: natural radioactive decay of one element into another. Compared to other radiation sources in the home and outside, the risk to the homeowner from radioactivity emitted from a granite countertop or tiles is practically non-existent.

How Much Radon is Given Off By A Granite Countertop and How Does This Compare With Other Household Materials?

Calculations show that, for an average countertop, containing an average uranium concentration of 4ppm (four parts per million), the concentration of radon that is given off by the countertop into household air is 0.00000074 pCi/L, an amount that is 270,000 times LESS than the level of radon in outside air.

The granite countertop typically emits a radiation level of 5-10µR/hr. So the maximum contact radiation level that you would receive over one year if you were to sit on the countertop all the time would be about one quarter of the annual radiation does from all sources. If you were just a few inches from the granite (e.g. when doing dishes), then the dose would be too low to measure.