Published on March 27th, 2009 | by Linda Kincaid, MPH, CIH13
Granite Showrooms Continue Selling Radioactive Granite
Last fall, Cathy Woods removed her Jupurana Bordeaux granite counters because they were radioactive. She did not want uranium ore in her kitchen, and she did not want to breathe the radon gas emitted by the granite.
The showroom that sold Cathy her granite had a new shipment of Jupurana Bordeaux around the same time. That stone was more radioactive than the granite they sold Cathy. However, sales staff told customers their granite was no more radioactive than soil or water.
We measured more than 500 microR/hour of gamma radiation from a slab of Jupurana Bordeaux on display in the showroom. At that dose, a person in close contact with the granite for an hour a day would receive 182 millirem of gamma radiation in a year. The Nuclear Regulatory Commission (NRC) recommends that members of the public should not exceed 100 millirem/year above background. No more than 25 millirem/year should come from a single source, like granite counter tops.
That particularly radioactive shipment of Jupurana Bordeaux is no longer at the showroom. The owner told Cathy he sold it to a developer, who was building a large number of homes.
There are several more shipments of Jupurana Bordeaux in the showroom now. Most of the new Jupurana Bordeaux emitted 50-150 microR/hour of radiation. One slab emitted over 200 microR/hr of gamma radiation. A person in close contact with that granite for an hour a day would get 73 millirem of gamma radiation in a year, three times the NRC recommendation.
Much of the granite in the showroom is radiologically “quiet”. The majority of the granite in the showroom emitted less that 15 microR/hour of gamma radiation. The radiation doses from those stones would be trivial.
It would be a simple matter for the granite industry to remove problem granite from showrooms and be honest with their customers. But at present, buyers concerned about radiation exposure have no choice but to hire a professional to test their granite for them.
Photo of Jupurana Bordeaux by Linda Kincaid.