Does Granite Pose a Radon Danger?

Granite Counter

Radon is back in the news. Radio personality Paul Harvey, the New York Times, and other news outlets reported recently that granite countertops pose a threat of emitting radon gas. Radon gas has been purportedly linked to risk of lung cancer. The Marble Institute of America has responded with a scholarly report essentially saying that the radon emissions from granite are so miniscule that they warrant no fears.

It seems that this report surfaces every ten years, or so. It has been promoted by the makers of competing countertop materials, like quartz products like Cambria or Silestone and solid surfaces like Corian. You can read and listen to the reports for yourself, but it seems to me that this is a Chicken Little issue that grabs the media’s attention and the stone countertop industry then has to spend lots of time and money de-bunking it.

Personally, I think that the threat presented by radon, in general, is way over-blown. I have never seen a positive, scientific, statistical link between radon levels and actual cases of lung cancer. All I’ve seen is pure speculation and panic prospering propaganda. The literature tells you all of the risks and dangers radon poses without actually showing that any of these dangerous consequences have ever occurred. None of the literature even acknowledges the effects simple ventilation has on dispersing the gas. Radon occurs naturally in the soil and rocks and it comes into a house through the ground. It can not be stopped. Ventilation is the remedy for houses that contain too much radon. The amount of radon that a stone countertop “might” emit is a small fraction of what occurs naturally and opening a door to the kitchen will remove any accumulated radon gas.

I think this is another example of irresponsible journalism, if you can call it journalism at all.

Click on the comment bar to tell us your story.

I hope this information is helpful to you. You might want to get yourself a copy of my best-seller, Designing Your Perfect House. It is chockfull of valuable tips and advice that will save you many times the cost of the book on your house building or remodeling project. You might also like The Well-Centered Home: Simple Steps to Increase Mindfulness, Self-Awareness, and Happiness Where You Live. It will show you how to make your home a happy place.

Bill Hirsch | Architect

Bill Hirsch


  1. Huligar on September 8, 2008 at 12:13 pm

    As you are probably very aware, there have been on-going accusations that have been consistently made against natural granite products having the ability to cause cancer, because of the high levels of radon that they have been said to produce. These accusations have been going on for quite a while, and it is time to put them to rest.

    Who better to accomplish this, than professionals who strive to ensure the safety, as well as the satisfaction of all customers? The National Stone Restoration Alliance is ready to put accusations to rest. Josveek Huligar, a proud member of the NSRA is willing to conduct a very important test in his own home. This is a test that can ultimately change the world of granite, as we know it.

    Huligar plans to have the very slab of granite, which was said to be ‘hot’ and to have contained radon, installed in his own home. The entire process will be on camera no less, for the entire world to see. Before the slab of granite is to be installed, samples will be taken, and the air will be tested in the home, as described by the EPA, and then sent to be evaluated by AirChek ( ), to check for traces of radon and radiation. When this test is complete, the granite will be installed, and then his home will be tested once again to check the levels of radon and radiation. You can monitor this entire process yourself on a public web cam at

    The slab being used for this test has been provided by Mr. Tim Scarlata of Atlantic Granite & Marble ( ), located in Rochester N.Y. After searching extensively to find the perfect slab for the test, Scarlata was able to locate two slabs of granite that did in fact produce higher than normal readings of radiation. Atlantic Granite & Marble will also be fabricating and installing the counter top while on video for the public to view.

    There have been some individuals who have spent large amounts of money on not only the installation of natural granite in their homes, but then they have turned right around and paid tons more money in having the granite removed because of the scare that has been put on society with the radon issues. Huligar, being in the business of ensuring customer satisfaction and quality, also takes this issue very seriously, because the health and well being of his customers are at stake. He plans to do everything possible to ensure the continued safety and reliability of NSRA customers.

    You could certainly be seriously hurt, or even killed if granite were to fall on top of you, but at this time, this is the only way that has been proven to cause harm to anyone.

    It is the believed that the radon scare is nothing more than marketing strategies, and it has done exactly what it was intended to do, and that is cause fear of using granite in the general public. Huligar and associates of NSRA do not believe this to be true. However, he knows how important it is for the public to see that he stands behind the good name of The Natural Stone Restoration Alliance and their objective to supply clients with the natural beauty of stone, and that every effort will always be taken to do so in a safe manner. To further put the publics mind at rest, solutions to any unfavorable characteristics have already been found.

    This test is vital to the natural stone industry, and Huligar is ready to stand up to the test to prove that granite is not harmful to the general public. People need to be able to see these accusations called upon.

    The Natural Stone Restoration Alliance (NSRA) has already done their own research, and released their information that looked at both past and present studies, as well as the marketing strategies used by manufacturers that birthed the scare of radon in the home. The findings of this research are quite simply that levels of radon have no significant difference when granite has been installed in a home.

    Do not let yourself fall into the trap of letting unproven fears cost you hundreds of dollars, find out the truth yourself by watching the web cam at Natural Stone Restoration Alliance | Home, and let this door be closed once and for all. Viewers can also comment on the research that is being performed at

    The set up and testing of the hot slabs starts 9/6/2008 at 10am.

    The test will be ending September 8, 2008 @ 6:15

    Web Site:

  2. Al Gerhart on October 12, 2008 at 9:54 pm


    There is a lot more to this issue than you are aware of and the dangers of some types of granite are well known. The last AARST convention ended with the CRCPD and AARST starting the process to set protocols for testing and maximum allowable limits for both Radon and radiation.

    Check out my blog, lots of info on this topic. Although the stone industry is fighting hard to bottle this up, there are too many researchers working on the issue now to stop it.

    Thanks for discussing the issues,

  3. Al Gerhart on December 25, 2008 at 11:59 pm

    Both the CRCPD (state radiation officials) and AARST (Radon scientists) are currently meeting to set maximum allowed radiation/radon standards and measurement protocols for granite countertop materials. This controversy has been embraced by the scientists as being truly of concern.

    We [are] currently conducting a full scale radon test, 18 square feet of granite in a 96 square foot room has elevated the Radon levels to over 10 pCi/L, about like smoking 1 1/2 packs a day according to EPA information. Here is a link to veiw the test and the current results.

    By the way, old Huligar clammed up on this subject a few weeks back after finding out exactly how much Radon his top was actually putting out. Seems the leaky apartment made him think it was a lot lower than it was. In a modern home, his countertop would become a major risk.

  4. Bill Hirsch | Architect Bill on December 26, 2008 at 10:21 am

    Al – I have a couple of questions for you.

    First, why is this test being done in a 96 square foot room? That seems pretty small for a kitchen in a house where granite might be used.

    Second, what type of granite is being used in the test? It is my understanding that not all granites emit the same levels of radon and that some are much more active than others. My understanding is that the stones that are at the lower end of radon emissions account for the vast majority of countertop sales.

    Third, is the test room completely enclosed? If so, I would suggest that not many kitchens are totally enclosed, but usually have openings to other rooms, often without doors, thus increasing the cubic feet of air substantially.

    Fourth, does anyone ever go into and out of the test room like people would do frequently in a normal kitchen? Ventilation of the room can have a huge impact on the radon readings. Is the room ventilated with heating ducts or air conditioning ducts? Is there an exhaust hood for the range as you would typically have in a kitchen?

    Fifth, would you please clarify for the readers your affiliation so they can put your point of view into perspective. You say “we are currently conducting…a test.” Who is “we?” Who is CRCPD?

    For readers who may not know the term, “solid surface” refers to products like Cambria, Silestone, etc. These products are made of quartz chips bonded together in a resin and formed to shape slabs for use as countertops and other surfaces. They are a direct rival to granite so any negative press granite might receive would necessarily help the solid surface industry. The granite and marble people claim that these allegations about radon risks in granite originate with the solid surface people. Al’s comment comes from the Solid Surface Alliance forum. They have commissioned their own independent testing. you can see their sixty page report at:

    But briefly, their overview conclusion is that “external doses of ionizing radiation emitted from granite countertops are well below levels that would pose a health concern” and “contributions from granite countertops to radon levels in homes are lower than background levels of radon exposure typically found outdoors and indoors.” The tests were conducted by Environmental Health & Engineering, Inc. in Needham, Massachusetts.

  5. Al Gerhart on December 27, 2008 at 7:56 pm

    Hi Bill,

    Excellent questions. I’ll try to clear things up as best I can.

    The size of the room was chose for several reasons, first being that it is a common size in our area (I used past jobs we have done, cross checking footage of countertop versus floor footage). Second, and most important, this size room had already been used for calculations by other researchers. We all try to keep things similar if possible, makes it easy to compare results.

    It is small for a kitchen and we are all very aware of the ability of ventilation to affect the levels. But this test was designed by a guy that published two papers on the subject at the AARST conference this year. The square footage of both top, the cubic footage of the room, and the ACH (ventilation amount) is all accounted for when figuring the real purpose of this test, computing exactly how many pCi of Radon are emitted per square foot of granite per hour. This entire test is just to verify what the scientists have already found (three have already measured samples from a sister slab, two more are currently measuring samples from this slab).

    Four Seasons is the granite, a close cousin to the Bordauxs. You are completely correct that many granites emit low levels of Radon. From 8 pCi/L up to over 1,000 pCi/L from the few samples tested so far.

    Please understand that I am a granite fabricator, that NO ONE in our testing effort has ever said that ALL granites were high Radon producers. But the ones that are dangerous MUST be found, pulled off the market, and pulled out of existing installations.

    Yes the room is completely enclosed, since we are after the emanation rate confirming the scientists findings, not how it affects homes. That will also be studied as part of the test. Now ACH stands for Air Changes per Hour, and we have plenty of experts on that topic giving advice. There are established rules of thumb for a room with one door, a closed door, a door and a window and so on. You can even find how one room leading to another with various openings will perform.

    In our case, we use CO2 tests ran alongside the Radon tests to prove the ACH levels.

    Now, we do know that the room with the door open continuously (approx 2′ x 6′ opening) tends to stay at 2.5 pCi/L, we checked it prior to sealing the room. We know that the concrete and normal background Radon in the air is responsible for .775 pCI/L of that radon.

    As to the ventilation affecting Radon levels, that will be the next step in the test. One of our experts, an Industrial Hygienist backed by a company ran by a PhD, has shipped us a flow meter. Once we have that meter, we will install a fan, in a manner that we can measure exactly how much air is removed per hour. Then an ACH test with CO2 will verify the results.

    At that point, we will be able to run the Radon tests at varying ACH levels. Condos have been tested as low as .03 ACH, which is what we have currently during out tests. Older homes tend to be more leaky, round .5 ACH, newer homes test around .1 ACH according to the experts at AARST.

    So yes, we are starting with the worst case scenario. That is standard practice according to the Industrial Hygienists, after all, why test for low amounts before figuring the worst case? If there is no danger at the worst, there will be no danger at low levels.

    We do open the window to change tapes on the CRM or set off more CO2 cylinders. That is fairly safe. Yesterday we opened the hatch, doubled the amount of granite (all low radiation level stone), swapped out the empty CO2 cylinders, changed paper on the CRM, general housekeeping. It took about twenty minutes, with the room falling by half to around 5.6 pCi/L. Of course our inside 20″ box fan was running the entire time causing the level to drop faster. Even with a HEPA half face mask, I didn’t feel comfortable being in the room at full levels.

    A range hood has been purchsed for eventual use in the room. We first have to find out how long one usually operates, then turn it on once a day for that length of time. I can tell you that we rarely use ours except for smoke.

    When I say “We”, I am refering to my company which makes cabinets and countertops of all types. I started fabricating granite three or four years back, and started looking into the Radon/radiation controversies before I started actually selling the product. This guy is not going to be sued ten years down the road over this.

    This entire project started off from a countertop forum, multi material shops mostly. As we found out more and more, more and more shops stopped supporting the work. I thought they would embrace it, after all if there was a danger, we ourselves were being harmed, our employees who we must protect with due diligence, and our customers can sue us for what we don’t know.

    Also when I say “We” sometimes I include the team of experts advising and loaning equipment for the test. The Radon and radiation protection industry is fairly small and interconnected at many levels. For instance the CRCPD meets at the same time and place as AARST.

    CRCPD is the state radiaton officers organization. AARST is the Radon scientist organization.

    Solid surface and Quartz are two different products, but they are connected. Solid surface is the same product used to make some dental work, ATH (Aluminum Tri Hydrate) and Acrylic resin. There are some types of solid surface that use polyster resins with the ATH, some use pure polyester.

    Quartz is a polyester resin with quartz chips and dust added. Some brands like Cambria do compete with granite, others like Silestone, Ceseasr Stone, and Zodiac have their own lines of natural stone. Silestone, one of the companies that helped start Build Clean, is one of the largest natural stone importers.

    I do run the Solid Surface Alliance Forum, and I do also sell solid surface, but like most countertop shops these days, we have to sell it all to stay in business. Look around the site, I show the bad side of the granite business, but I also have a section on how to work granite and encourage all the remaining solid suface shops to start fabricating and selling the product. Just test if first, and sell it honestly. I also show cases where solid surface companies have screwed over consumers.

    Now you seem to have confused us and the MIA (Marble Institute of America). They have paid for two studies this year, both unpublished in scientific journals, both not peer reviewed, both worthless except to mislead consumers, which was their purpose. No one will take their word for this as they have attempted to cover up this issue for the past 24 years.

    Look around the and you will find a report on their first “study” and it’s many shortcomings, the one written by Dr. Chyi.

    I have a copy of the entire McCarthystudy (E,H, & E), you have read the Executive Summary that you referenced below. I am about half way through the study, poking holes in it. For instance, they used the average uranium in granite sold in the use to calculate their Radon levels. On one of the professional Radon forums, one state Radon official said their claims were ridiculous, that if the soil based Radon problem was looked at the same way, with the average U S home Radon level of 1.3 pCi/L, one would consider there not to be a problem with Radon despite the high levels found in some homes.

    Plus when one makes broad statements like the MIA does, allowing for absolutely zero hot slabs, the work that Radon scientists have done already show the MIA to be lying through their teeth. The videos we posted measuring hot granite way over 100 times background also show the lack of honesty in their report.

    Did they find some low level slabs and test them? No doubt they did. One must ask why they didn’t test the slabs that were hot, they are easily found all over the nation.

    This is like Ford responding to burning Pinto’s by studying Volvo’s.

  6. Al Gerhart on December 27, 2008 at 8:00 pm

    I forgot to mention, the 18 square feet was purposely set at around 50% of a normal small kitchen footage. We wanted to be conservative with the first test. Adding another 18 square feet brings it to the low end of the average small kitchen, 36 square feet. 45 feet is more the average small kitchen.

  7. Al Gerhart on December 27, 2008 at 8:07 pm

    Opps, a typo. The MIA has been covering this up for 14 years, not 24 years.

  8. Bill Hirsch | Architect Bill on December 27, 2008 at 8:25 pm

    Al – Thanks for your answers to my questions. I’ll leave it to my readers to take it from here.

  9. Granite on January 30, 2009 at 12:06 pm

    Very interesting post you wrote. Glad I have stumbled upon it. Cheers!

  10. proxy on January 31, 2009 at 8:27 pm

    Thanks, good article. Do you know any other places that discuss this?

    • Bill Hirsch | Architect Bill on February 1, 2009 at 11:18 am

      There are a number of sites that have commented on this subject. You might want to check out the marble Institute of America at

  11. Al Gerhart on February 15, 2009 at 8:13 pm

    The MIA is currently being given a good spanking by some of the researchers looking at their latest “study”. One researcher called the study in the E,H, & E report “untrustworthy”. In a public comment on a Radon forum, he blasted the report for lacking detail, being confusing, and claimed the MIA had yet to answer his extensive list of questions so he could attempt to make sense of the study.

    Another researcher found Radon from samples of the same type that the E,H, & E study, up to three orders of magnitude more (1,000 times more).

    Be sure an take a look at the MIA (marble institute) site, but for accurate information visit

  12. A Granite Radon Question on March 28, 2010 at 9:39 am

    […] a question from a reader about radon emissions from granite countertops the other day. I wrote a blog post about this a while ago. But this question comes up over and over again, so I thought I would post […]

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