One of the things that many homeowners are concerned about is the issue of granite radiation. Granite has grown in popularity as building materials, particularly for kitchen countertops because they are not only beautiful, but also functional. Over the past couple of decades, however, there have been reports that some granite countertops may be emitting dangerous amounts of radiation, specifically radon gas. This is a radioactive gas released by uranium as it decays, and believed to cause lung cancer. Should homeowners be worried? Here are the facts about granite radiation.
The nature of granite
Granite is an igneous rock, originating as magma and formed over millions of years under intense heat and pressure. The Marble Institute of America (MIA) states that granite naturally contains not only uranium but also other radioactive materials such as potassium and thorium, but in such small amounts that they pose no threat to human health. Most natural stones, decorative or otherwise, will also contain such materials as a matter of course. This does not mean that they are dangerous to humans, or that all natural stones will have the same level of radioactive materials. In fact, since granite is not particularly porous, it is unlikely to release radon gas in any appreciable amount even over a long time, especially if it is sealed.
It is also important to understand that measuring radioactive levels is no guarantee of danger or safety, According to the Nuclear Information and Resource Service, “All life on Earth is exposed to and impacted by natural sources of ionizing radiation. …When a living being absorbs it, that individual has received a “dose” of radiation….one radiation particle can cause great damage to a single cell; that damage can even lead to a person’s death, while registering a dose to the total body of zero!” Prolonged and high levels of radiation exposure is thought to be harmful to living tissue, but the absence of a reading does not mean there is no radiation. In other words, no one really knows.
Radon facts
Radon is definitely deadly. It is one of the leading causes of lung cancer, second only to smoking. The risk increases for smokers, whose lungs are already in a vulnerable state. Radon and other forms of radiation can also be dangerous to developing fetuses and children.
However, studies on radon and radiation levels from granite show no evidence that they pose a threat to human health. It is possible a slab with high levels of radioactive materials can adversely affect anyone that stands in close proximity to it for a considerable length of time a day, but this is unlikely. It may be more dangerous to spend a lot of time in the basement, where the soil naturally releases such radiation, or being a frequent flyer.
Putting it in perspective
Health experts agree with the findings of radiation experts that the radiation emission of most decorative granite countertops are extremely low, much less than the regular exposure most humans experience from outer space or from the soil. These are definitely less than the radiation emitted by luminous watches, X-rays, and even smoke detectors.
The Environmental Protection Agency and the Nuclear Regulatory Commission reports that the average person receives about 360 millirem of radiation every year from natural and man-made sources. People living near nuclear facilities receive about 100 millirem additionally a year, and every time you fly from New York to Los Angeles, you receive another 3 millirem in cosmic radiation. The EPA recommends action when radon gas levels in the home reaches 4 picocuries, which roughly approximates the risk of cancer from smoking half a pack of cigarettes.
A “hot” granite countertop, or one that emits 10 times or more radiation than the typical granite slab, may perhaps add a fraction of a millirem for each hour that you are in direct contact or a few inches from it. The Columbia University’s Center for Radiological Research places the risk of developing cancer from emissions from “hot” granite slabs are about one in a million. You are more likely to be struck by lightning.
Developments
It cannot be denied, however, that an increasing number of radon inspectors and homeowners have been reporting incidents of granite countertops exceeding normal radiation levels to the EPA lately. This may be due to the entrance of new varieties from exotic areas into the US. The MIA is taking steps to address the problem of these new slabs by developing a testing protocol. MIA president Jim Hogan says, ” We know the vast majority of granites are safe, but there are some new exotic varieties coming in now that we’ve never seen before, and we need to use sound science to evaluate them.”
Concern over high readings are definitely on the rise, but even radiation inspectors admit that only a few granite slabs may possibly cause harm. In a recent study by Rice University in Houston, results showed that only a handful of samples contained high levels of radioactive emissions. Nevertheless, it has attained the status of black mold in terms of litigation, in that some cases may sustain a claim for personal injury, while a majority will simply have no merit.
Conclusion
Despite the hype, many homeowners continue to use granite for the home, but have become more cautious about the stones they select as a consequence. Some homeowners that had to remove their “hot” granite countertops have opted to replace them with granite still, but had them tested first before installation. A typical inspection by a technician certified by the American Association of Radon Scientists and Technologists costs between $100 and $300. Homeowners can allay their own fears by having their granite countertops tested by a certified technician, or by buying a home radon testing kit available for about $20 at the Environmental Protection Agency’s Web site (epa.gov/radon) or from state or regional indoor air environment offices
(epa.gov/iaq/whereyoulive.html).. Most will have wasted their money, but it will give them peace of mind.
References:
http://www.sciencedirect.com/science/article/pii/S0265931X11000580
http://www.nirs.org/factsheets/mythmiliremfctsht.htm
http://www.nature.com/jes/journal/v20/n3/abs/jes200943a.html
http://www.sciencedirect.com/science/article/pii/S0265931X10000202
https://www.epa.gov/radiation/granite-countertops-and-radiation