Granite Countertops and Radon – THE REAL TRUTH
As many of you may be aware, the current ‘mania of the month’ is “Are my granite countertops emitting Radon”. I must admit, the first time I had a customer call me with this question, I was torn between “that’s crazy” and “hey, that could be possible”.
Not much to my surprise, I have discovered that in many cases the origins of these concerns are advertisements by manufacturers of competing materials!!
Levels of radon gas from granite-based products, while technically measurable, are in fact fractional values of established thresholds for environmental safety. So, with that being said……….
THE BIG QUESTION: Is radon in granite countertops dangerous?
There are two ways in which countertops made of granite might emit any level of radiation. The first is by release of tiny amounts of 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, but the end result is the same: compared to other radiation sources in the home and outside, the risk to the home-owner from radioactivity emitted from a granite countertop is practically non-existent. The amount of radon gas emitted by a granite countertop is less than one millionth of that already present in household air from other sources! ONE-MILLIONTH! 1
Q: How much radon is given off by a granite countertop, and how does this compare with other household materials?
A: For an average countertop, 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 maximum contact radiation level that you would receive over one year if you were to sit on countertop all the time would be about one quarter of the annual radiation dose you already receive from all sources. Even If you were just a few inches away from the granite, then the dose would be immeasurable!! 1
Q: What about food that is prepared directly on the granite surface? Is there a chance that it could absorb radioactive energy, which would later be ingested by those eating the food?
A: The only way that radioactive elements such as uranium can get into the food is if they became dissolved in water and absorbed by the food. However, granite is one of the most insoluble materials known to mankind and the amount that could be dissolved is minute in comparison to the radioactive elements that are already in the food! 1
As an inspector, I always recommend that you have your property tested for radon by a qualified specialist who uses an EPA-approved testing method and certified laboratory. Spare yourself and/or your customers the expense of additional testing over fear of radon emissions from your granite countertops…!
1 – “The Truth About Granite & Radon/Radiation” – Marble Institute of America (http://www.marble-institute.com), Vol. IV, Issue I, March 2007
Mike Ciavattieri is a Massachusetts Home Inspector and owner of BONSAI Inspection Company, of Abington, MA