Some granite emits substantial amounts of radiation and radon gas. There is no way to tell which stones are radioactive just by looking. Testing is the only way to know for sure. However, the problem granites are more likely to be exotic and to have a lot of “movement”, such as swirls or banding.
Some granite emits enough radon to increase the radon concentration in a kitchen. The radon in Cathy Woods’ kitchen was three times as high as the radon in her bedroom. That lung cancer risk at that level was nearly as high as smoking 10 cigarettes a day.
Erica Marcus declared, “I was basically thrown out of a showroom today for mentioning radiation to the owner”. She says, “This tells a lot about the industry knowing about what they are selling”.
A homeowner in Menlo Park, CA recently discovered that his home had 14 picoCuries/liter of radon, three times the EPA action level of 4 picoCuries/liter (pCI/L). He tested his home for radon because he was concerned about his new granite counters. However, his granite was not the source of the radon. He had “geologic” radon coming from the soil beneath his house.
Cathy Woods’ new granite counters were radioactive. They contained as much uranium as commercial uranium ore. The showroom that sold Cathy her Jupurana Bordeaux granite did not warn her that some granite is radioactive. When I contacted the salesman, posing as a customer, he assured me their granite “is no more radioactive than soil or water”. However, Cathy’s granite emitted gamma radiation at many times background. The radon gas emitted by the stone tripled the radon concentration in her kitchen. [...]
By Joel Bittle •
September 18, 2008
This post is a follow-up to The Fight Over Radon in Granite Countertops Heats Up, which will provide some background information on the granite/radon issue.
With the legion of both deniers and alarmists out there attempting to monopolize the discussion over the safety of granite countertops, it is difficult to find unbiased information. Peruse the comments in the above post and you can see the discussion has devolved into name calling. The deniers, many of whom work in the granite industry, blast any insinuation that granite could be dangerous as “fear-mongering” and put down the current research as “junk science.” The alarmists, many of whom sell competing countertops, argue that consumers shouldn’t take the risk that comes with granite. The truth, as with most heated arguments, can be found somewhere in the middle.
By Joel Bittle •
May 14, 2008

Please visit an updated post on radon in granite countertops here: A Rational Discussion on Radon in Granite Countertops
The Marble Institute of America better get ready for another round of fighting because the issue of radon in granite countertops is back. For the past decade, the MIA has been trying, with much success, to squash the rumor that granite countertops have the potential to add dangerous amounts of radon in the home. A new study being conducted by Houston area not-for-profit BuildClean is raising old fears about the dangers of granite countertops, and its preliminary results show that while most granite countertops in the study contain very little to no radon at all, the countertops that do contain radon have levels that are frighteningly high. While consumers can be secure in the fact that the vast majority of granite is perfectly safe, a small percentage is still in question, and no independent scientific study exists to assuage consumer fears.
The first issue of Solid Surface in 1995 explored the possibility that granite countertops may pose a health risk. Soon, the MIA issued their response, which attacked the credibility of the science involved in the study as well as the fact that the advertisers in the journal included companies that competed with granite countertop manufacturers. But one phrase in the response, a highlighted phrase no less, is troubling: “…actual levels of radon gas emmissions are so low as to be insignificant and generally represent no threat.” As a father, I don’t want to be assured that there is “generally” no threat to my family. I want to know there is no threat. And after BuildClean* found that 3 of 95 granite countertops contained harmful amounts of radon, would the MIA consider such a small number to be “generally” no threat? I’m sure the owners of those three countertops are not reassured.