New Findings on Radon from Marble Institute of America

New Findings on Radon from Marble Institute of America

April 10, 2014

In their efforts to provide the most accurate and up-to-date information possible to our industry, the Marble Institute of America (MIA) has recently commissioned two new studies on the relationship between granite and radon/radiation. So, reflecting “our” goal of keeping you, the consumer, informed of the very latest in the natural stone world, we’d like to share the results of those studies with you.

Bross Black from Marble and Granite, Inc.

Bross Black Polished; photo via Marble and Granite, Inc.

Basically the two studies measured the radiation dose of workers during fabrication of granite as well as the radon exposures in a granite quarry. And their findings confirm what we’ve been saying all along—granite countertops do not emit an amount of radiation significant enough to be considered “dangerous.”

Key findings from the MIA studies include:

• Radiation doses due to fabrication of granite are very low, and well below both occupational standards (5,000 mrem/year) and limits to the general public (100mrem/year).

• According to the Mine Safety and Health Administration (MSHA) , all active granite quarries in theUnited States are considered to be surface mines, and therefore are naturally ventilated.

• Air monitoring at varying heights in a deep quarry in Vermont (selected to represent a ‘worst-case’ scenario) recorded a background radon concentration of “less than average.”

• Temperature inversions have little to no impact on workers’ average annual exposure to radon.

• Occupational exposure to radon for granite quarry workers is insignificant.

It’s important to remember that all natural products, especially stone, minerals, and sand, contain trace amounts of some radioactive elements called NORMS (or Naturally Occurring Radioactive Minerals) that can produce “measurable” amounts of radiation, and sometimes radon gas. But the key word here is “measurable.” It’s not true that all granite countertops emit alarming amounts of radon. In fact, most tested register no release of the gas or such small quantities that it was significantly insignificant when compared to ordinary background radiation that we all live with.

Would you like to read full reports on these, or any other studies conducted by the MIA, please visit


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