The Dangers of Granite

Holy Smokes! There is Something to That NY Times Article

While the original NY Times article about radon in granite countertops could be seen as hyperbole and a media campaign against the high end countertop industry, after reading the industry response, It may be the coming onslaught of a wave of fear brought on by the real danger of radon.

The problem is in the industry’s own independently cited research they try to prove that granite is safe by underestimating the amount of granite in a typical home. Then use average home sizes in the entire US instead of more typical home sizes in New York City (The NY Times audience). The people of New York City area are generally confined to a much smaller home.
Here is the mind numbing math.
According to this article on CNN, the typical New York apartment is 1,300 square feet. Air volume equals square footage multiplied by the ceiling height. In the University of Akron study they used a container less than one cubic foot so in order to get a comparable ratio one must multiply the cubic footage of the housing unit by 1.49. So for the sample equation of a typical New York Apartment the volume is 15,496.

The University of Akron study uses a 13 by 2 foot countertop with a thickness of 2 centimeters, making the total surface area of the granite about 54 square feet. That number deceptively low as homes with granite kitchens are generally more modern and have at least two counters (one on each side of the kitchen or an L shape) as well as a back splash. In addition, many apartments also have a breakfast bar and additional counters in the bathrooms. Conservatively using 104 Square feet of total surface area is more typical for kitchens with granite counters. To use the University of Akron equation to get a comparable square footage one must divide by 2.5 square feet. So for this example our countertop surface area number for a New York City apartment is 41.6.

Since the study chose the highest level of radiation sample to down play the risks of radon gas in a home it makes sense to use the same sample to show the risks. The example stone in the countertop material gave off 292 pCi/L (picocuries per liter of air).


To figure out the radiation from granite in a New York City apartment one must use the equation
292 pCi/L X (the surface area of the counters with multiplier) ÷ (the volume of air in the home with multiplier) = the amount of radiation from the counter tops.
OR
292 X 41.6 ÷ 15522 = .783 pCi/L or almost three times the amount in the University of Akron study example.
To get to the crux and see if this fades into the general background radiation one must first consider the radiation already present in the typical home of 1.3 pCi/L
With the average radon level in a home at 1.3 add to this to the .783 from granite counter tops and the home is over background levels (2.0) and the University of Akron study suggests considering fixing the home. For example, if the homeowner is a non smoker the risk of getting lung cancer from radon increases from 2 per one thousand to 4 per one thousand, in other words, doubling the risk of lung cancer from Radon.
While not trying to cause a panic and not suggesting ripping out existing counter tops without testing. Testing of individual pieces of granite for radon off gassing prior to installation and getting currently installed granite tested would be a good start. It should also be part of a thorough home inspection before buying a home.
As an aside a red flag warning to the installers and fabricators cutting this stone or handling it in a warehouse where the exposure is much higher. Use the proper ventilators and other safety equipment.


Census Data


Age of American Homes