Stone Countertops & Radon - InspectionNews

Jeff Spencer · #1 (**permalink**) 05-09-2008, 12:22 PM

I caught the tail end of a news report the night before last that was either detailing or hyping the risks of radon posed by stone countertops.

Is this something any of y'all have dealt with, or is the local news (Houston, TX) trying to get ratings?

Since I live in a low-risk area relative to radon, I've never thought about before. Wish I'd seen the entire report, but I was engaged in serious mental drift about that time.

Jeff

Scott Patterson · #2 (**permalink**) 05-09-2008, 12:31 PM

Quote:

Originally Posted by Jeff Spencer

I caught the tail end of a news report the night before last that was either detailing or hyping the risks of radon posed by stone countertops.

Is this something any of y'all have dealt with, or is the local news (Houston, TX) trying to get ratings?

Since I live in a low-risk area relative to radon, I've never thought about before. Wish I'd seen the entire report, but I was engaged in serious mental drift about that time.

Jeff

It all depends on who is reporting and what source is being cited.
The Marble Institute of America (MIA) says that it is a bunch of bunk! Yet, other groups and scientist say that it is very possible to have a slab of granite emitting radon in a home.

I kind of lump it in with all of the elementary school playground equipment that was built in the 1960's and 70's with old oilfield drilling pipe. It was just metal pipe that was strong and cheap. Made great swings and monkey bars, but it had one little problem. It was radioactive a good part of the time.

I'm going with the non-industry view in that it could happen.

John Arnold · #3 (**permalink**) 05-09-2008, 12:49 PM

Supposedly from the EPA: (my bold)

"Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rock, and water. Air pressure inside your home is usually lower than pressure in the soil around your home's foundation. Because of this difference in pressure, your house acts like a vacuum, drawing radon in through foundation cracks and other openings. Radon may also be present in well water and can be released into the air in your home when water is used for showering and other household uses. In most cases, radon entering the home through water is a small risk compared with radon entering your home from the soil. In a small number of homes, the building materials (e.g., granite and certain concrete products) can give off radon, although building materials rarely cause radon problems by themselves. In the United States, radon gas in soils is the principal source of elevated radon levels in homes."

Michael Thomas · #4 (**permalink**) 05-24-2008, 10:06 AM

Gunnar Alquist · #5 (**permalink**) 05-24-2008, 01:06 PM

Interesting reading. Another thing to report and disclaim. Jeeze. Did anyone hear or read the recent reports on nanotubes, their similarity to asbestos and the possibility of mesotheleomia?

The conclusions in Michael's Marble Institute post recommend sealing the stone. As I recall, JP was on the fence about that in an earlier post.

Any (revised) comments, JP?

Jerry Peck · #6 (**permalink**) 05-24-2008, 07:30 PM

From the Marble Institute link: "Alternatively, if the crushed granite is used to make other building materials, radon emanation can also be a health concern"

Isn't that decomposed granite stuff crushed granite?

Then there is this:

"In the worst case as represented by Crema Bourdeaux at equilibrium is 292 pCi/Lx22÷24000=0.27 pCi/L.
The actual radon dilution factor can be much bigger than what is calculated. Radon from granite countertop can, therefore, only add a very small amount to the house when it is not used such as during the period of vacation. Radon from countertops cannot exceed the maximum equilibrium level because 222Rn decays quickly with a half-life of 3.8235 days."

Then this:

"Conclusion
The testing procedures for radon emanation of granite countertops are designed for normal use of these stones only as countertops. Adapting the 4pCi/L action level as recommended by US EPA as a reference and the house is not in active use, Crema Bourdeaux countertop raises less than 7% of this action level. The second and the third highest radon count stone Tropic Brown and Baltic Brown can add only approximately 1% of this action level. All the other countertops adds only insignificant amount of radon to the house. If normal air exchange rate is applied or the house is actively used, then the radon addition should be much smaller."

That basically tells me not to worry about it.

Al Gerhart · #7 (**permalink**) 06-07-2008, 04:33 PM

Jerry,
That MIA article is highly suspect. They have a history of hiring a "study" done, without insisting that the work be sujected to peer review and publication, two marks of a truly scientific study.

The testing that Dr. Chyi did was okay according to experts in the field, indeed he found that Crema Bordeaux emitted like 292 times more Radon than some of the others! Where this effort went wrong was in the conclusions.

To start with, they used a 13' x 2' granite countertop as the example home, a 2,000 square foot home. Then to make it seem more reasonable, they doubled the square footage by counting top and bottom square footage, bringing it up to 54 square feet. I missed it the first time I read it, had to go back after a nagging feeling that the levels emitted were low.

I can tell you that the average countertop in a home of that size would be between 65 and 75 square feet, so if Chyi said to count both sides since both sides emit the Radon (ignore the edges for now, but they emit as well), that 54 square feet becomes between 130 and 150 for the kitchen alone. Triple his emission from .27 to .81 pCi/Liter. Four picoCuries per Liter have a lung cancer rate of 7 per 1,000 exposed(adults only), according to the EPA, and the relationship is linear, so .81 pCi/L will cause 1.41 cancers per thousand exposed, hardly a small risk factor. Children have 10 times that risk factor according to the NRC and the EPA.

Still serveral problems remain with this conclusion.

First off, There will be far more granite in some homes. Our average granite jobs in a home that size is two slabs, 100 to 120 square feet in the kitchen tops in some cases alone. Add the granite tile flooring, the vanity tops, sometimes shower tiles and you can have a lot more total square footage that would add to the Radon levels in the home. We commonly put three slabs in homes of 2,000 square feet.

Secondly, they are assuming that Crema Bordeaux is the highest radioactive level granite, far from it. Crema Bordeaux is pretty mild stuff, around 20 to 25 uR/hr Gamma emission (Gamma emission is an indicator of the Radon emission, roughly the same). Other granites like Jupanara Bordeaux (shorted to Bordeaux), Shivakaski, Niagara Gold, Four Seasons, Bariacotto, Savanah, and many other granites are far higher. The highest level slab found so far is Savanah, which had hot spots at 1030 uR/hr! I have personally measured 800 uR/hr and higher, plenty of 500 and 400 uR/hr granites slabs around.

So, the second point it that the Crema Bordeaux at 25 uR/hr is very low, 41 times less than the highest level slab found to date. That .27 pCi/L becomes 11 pCi/L when using Savanah. Shivakaski with very high levels has been found in two homes, both failed a Radon test till the granite was removed! The Houston home in the story returned to normal levels after the granite was removed.

Thirdly, that 292 pCi/L that the Crema Bordeaux emitted would eventually spread out all over the home, but what about a homeowner using the kitchen countertop? They are breathing concentrated levels, up to 292 pCi/L according to Dr. CHyi, all the while they are standing near the top. The kitchen, as in the Houstone example, will be far higher Radon level as well. In the Houston case, there was no concern in other areas of the home. The Radon didn't spread out as expected.

In the conculsions, they mention air exchange, up to 6 total changes per hour. Not many homes are in areas where that kind of air exchange can be affordable. Here in Oklahoma, we open the windows rarely, either too hot, too cold, or too many mosquitos. The point is, who ever wrote that section of the article (it wasn't Dr. Chyi), used a massive air exchange rate to further minimalize the risk.

In the end, the granite that we sell, we test before purchase. Some gets rejected, anything over the UN levels of 41 uR/hr. Every slab yard will have multiple slabs of granite way over this level, usually one very, very hot slab, up above 100 uR/hr Gamma. So despite the MIA's article on this issue, there is some concern in the industry. One of our vendors is helping the testing effort, supplying hot granite for testing, and the guy has canceled orders of incoming material that we found to be hot, as well as canceling sold orders of hot material we found in his inventory.

So far, three granite countertops have been removed after being found to raise kitchen Radon levels over 14 pCi/Liter. Then again, hardly anyone knows to look for this problem, and if the MIA has its way, it will stay that way.... The Houston countertop in the story had a previous homeowner develop a brain tumor while living in the home. Dr. Llope, the nuclear Physicst in the TV report, was very skeptical at first. Now he is using his Lab to test granite samples in his free time and speaking out about the radiation levels that a granite countertop can emitt.

I have a blog started about this issue if anyone is interested,

solidsurfacealliance.org Blog » Granite Radiation

And on Youtube.com, we have some short videos of a radiation meter shrieking its little guts out from the Gamma radiation coming from a granite slab. YouTube - TCSRock78's Channel

Brand new meters, calibrated to military specs by an expert.

Heads up guys, we sell granite and it can be a concern. I lost a $10,000 granite job last month because the material was too hot to fabricate. One of my competitors has fewer scruples.

Thanks,
Al

wayne soper · #8 (**permalink**) 06-07-2008, 05:21 PM

Man, And I always thought it was what you sniffed off the granite countertops that killed you. Wake up and smell the rocks.

Jerry Peck · #9 (**permalink**) 06-07-2008, 06:20 PM

Quote:

Originally Posted by Al Gerhart

To start with, they used a 13' x 2' granite countertop as the example home, a 2,000 square foot home.

I can tell you that the average countertop in a home of that size would be between 65 and 75 square feet,

Al,

I just came back from the house my daughter is building over in Williston, FL. It is just under 2,000 sf in size (conditioned space) and her granite countertop is probably close to 13' x 2', maybe just lightly more, but not much (had I known of this post I could have measured it).

I read the article, it seems to me that, all things considered in the article, that the radon produced by the granite is not something to worry about, much lower than the action thresholds.

Guess it is to each reader to 'read into it what they want'.

Al Gerhart · #10 (**permalink**) 06-07-2008, 07:31 PM

Jerry,

We do usually do three or four kitchen tops a week. And there are yearly surveys on this matter, top size, materials most used, price points, ect. The industry average is between 65 and 75 square feet. Sure some kitchens will be smaller and some larger, thus the average and the range.

26 feet is a small countertop, less than one sheet of solid surface. Average job takes 2 1/2 sheets.

And, in the type of kitchens that do high end cabinets like we produce, they tend to be larger than average. The most I ever put in one kitchen was 300 square feet of material.

I appreciate skeptical thought, glad to see that in an inspector, but if you re read the MIA puff piece, you will notice that they didn't touch the radiation issue, just the Radon emission. The guy that did the TV interview, Dr. Llope, has a website on this issue if you want to see what he is saying.

Web home: Radiation & Radon from Natural Stone, W.J. Llope

Or read his report for the TV station.

http://www.khou.com/images/0805/LLOP...dRn_080507.pdf

Keep in mind that Dr. Llope was not the expert that the group wanted, Dr. Llope was brought in for an independant opinion. Now he is testing granite...

Now, turn that excellent, skeptical, inspector mind to why they didn't address both the Radon and the radiation danger from granite?

I'm just saying.....

Matt Bezanson · #11 (**permalink**) 06-09-2008, 08:25 AM

One more idea on radioactive countertops: Several ideas, actually,

I have tested a number of different stone counter materials in an informal way, and none were hot. However, I have direct knowledge of one that was quite hot, detected by a CRM moved to the counter after the basement test was done, but not turned off. (long story, realtor involved). It's pretty clear that some stone is radioactive, most is not. So if it's your house, or your family's house, the obvious answer is to test. Test the basement, test the bedroom, test the kitchen, test the air right on the counter or stone floor or stone shower enclosure. Passive tests are really cheap, nearly free from many county health departments. Deploy a half dozen of them at the same time, and have fun interpreting the results

In a real estate transaction, active tests are more likely to be in use, and are much more expensive. Not likely you could talk a client into multiple tests. I've done a few that way at the customer's request, one CRM in the basement, one in the kitchen, and my customers were glad to know that their stone wasn't hot.

The comment by the manufacturer association about the equilibrium ratio, and the half life calculated to the ten-thousandth of a day was amusing. Does anybody know what it means?

When assessing cancer risk, it's the lifetime dose that counts, not the instantaneous exposure to any one source. So the problem with stone is its contribution to the overall house radon level. (Same as with radon in water.) However, if you have an unacceptable radon level in the home, it would be really good to know where it's coming from, so you don't waste time, effort and money mitigating the wrong place. That's the only good reason for multiple tests.

Matt Bezanson, NEHA RMP101003RT, NRSB RMS # SS75

Caoimhín P. Connell · #12 (**permalink**) 06-09-2008, 09:13 AM

Good morning, Gents –

Here's a thought from my perspective as a practicing epidemiologist and toxicologist. The entire argument is debating how many angels can fit on the top of a pin.

Two things:

One-
There is NO evidence whatever that the concentrations emitted are associated in any way with adverse health effects. Arguments about the emission rates and resultant indoor concentrations are arguments of futility. It is rather like arguing whether the US population is at risk, because the average height of a coffee table is 15.25 inches or 15.5 inches. Until someone can demonstrate that the height of coffee tables has anything to do with adverse health effects – the rest of the argument is largely a fool’s errant.

Two-
None of the studies I have seen have been able to show a significant difference in radon concentrations in homes with the counter tops, and then without. None. After all, it would be sooooo easy to do. Take 100 houses and monitor the average concentration in those houses over the course of 24 months. Pair match 50 pairs, and install counter tops and measure the radon concentrations for 24 months. Do the math. Why hasn’t this been done? Because the costs aren’t justified, because the risks aren’t there.

One might as well lie awake at night worrying about whether green seatbelts are safer than black seatbelts.

Cheers!
Caoimhín P. Connell
Forensic Industrial Hygienist
Forensic Industrial Hygiene

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

Jerry Peck · #13 (**permalink**) 06-09-2008, 10:32 AM

I can only add this: On the houses I've inspected with large areas of stone countertops, the areas of stone floor make the areas of the stone countertops negligible, percentage wise.

With 10,000 sf ++ of stone flooring, what effect is even 300 sf of stone countertop going to contribute? >1/3 of 1%? As I said ... negligible.

Take a more moderate house, say 6,000 sf of stone flooring, and a relative reduction in countertops, say to 100 sf, that's 1/6 of 1% ... negligible.

Take an even more modest house, say 3,000 sf of stone flooring, and a relative reduction in countertops, say to 75 sf, that 1/4 of 1% ... negligible.

Al Gerhart · #14 (**permalink**) 06-09-2008, 04:55 PM

Hi Matt,

Quote:

Originally Posted by Matt Bezanson

One more idea on radioactive countertops: Several ideas, actually,

I have tested a number of different stone counter materials in an informal way, and none were hot. However, I have direct knowledge of one that was quite hot, detected by a CRM moved to the counter after the basement test was done, but not turned off. (long story, realtor involved). It's pretty clear that some stone is radioactive, most is not. So if it's your house, or your family's house, the obvious answer is to test. Test the basement, test the bedroom, test the kitchen, test the air right on the counter or stone floor or stone shower enclosure. Passive tests are really cheap, nearly free from many county health departments. Deploy a half dozen of them at the same time, and have fun interpreting the results

I agree, not all granite is hot. The Chinese have done more testing than other countries, indeed the law requires all granite be tested before bringing to market. They have a sticker, not unlike our Matteress tags that must follow the slab till it is installed. The Chinese say that between 30 and 20% of all stones fail the Class A rating (.3 mSv,yr exposure or 41 uR/hr gamma). What testing I have done shows around 3 to 5% of granite is of major concern, if you consider types of granite.

In a real estate transaction, active tests are more likely to be in use, and are much more expensive. Not likely you could talk a client into multiple tests. I've done a few that way at the customer's request, one CRM in the basement, one in the kitchen, and my customers were glad to know that their stone wasn't hot.

We are using Scintillators to indicate Gamma, not really looking for Radon. I think that is best left to the professionals. A Scintillator will tell you from 8 feet away if there is a problem..

The comment by the manufacturer association about the equilibrium ratio, and the half life calculated to the ten-thousandth of a day was amusing. Does anybody know what it means?

I can speak to the Equilibrium Ratio. Not sure I understand the nuances of it yet, but apparently the Radon at some point reaches max level because it is decaying into daughter products as fast as it is being produced, or that seems to be the gist of it. I have heard that around 21 or 27 days. Dr. Llope said to just open your windows for a half day every three weeks to prevent the Radon building up to the max levels.

I didn't find the half life calculated to ten-thousandths, what page was it on?

When assessing cancer risk, it's the lifetime dose that counts, not the instantaneous exposure to any one source. So the problem with stone is its contribution to the overall house radon level. (Same as with radon in water.) However, if you have an unacceptable radon level in the home, it would be really good to know where it's coming from, so you don't waste time, effort and money mitigating the wrong place. That's the only good reason for multiple tests.

Matt Bezanson, NEHA RMP101003RT, NRSB RMS # SS75

Thanks for the info. If you find a hot top, let us know the stone type and if you can release it, the homeowners info so we can contact them. Only three torn out so far, but every bit of data helps the scientists working on this effort.

Al

Al Gerhart · #15 (**permalink**) 06-09-2008, 05:12 PM

Hi Caoimhin,

Quote:

Originally Posted by Caoimhín P. Connell

Good morning, Gents –

Here's a thought from my perspective as a practicing epidemiologist and toxicologist. The entire argument is debating how many angels can fit on the top of a pin.

Two things:

One-
There is NO evidence whatever that the concentrations emitted are associated in any way with adverse health effects. Arguments about the emission rates and resultant indoor concentrations are arguments of futility. It is rather like arguing whether the US population is at risk, because the average height of a coffee table is 15.25 inches or 15.5 inches. Until someone can demonstrate that the height of coffee tables has anything to do with adverse health effects – the rest of the argument is largely a fool’s errant.

A couple of questions. The EPA recently changed their position on this issue and is now recommending granite top owners to test their homes for Radon. Some concern must have been present to change their advice from not to worry to worry....

It seems that there is quite a bit of Radon health risk info out there. Is there a reason you don't hold with what they are saying? The Radon health risk seems to be accepted worldwide at this time.

Two-
None of the studies I have seen have been able to show a significant difference in radon concentrations in homes with the counter tops, and then without. None. After all, it would be sooooo easy to do. Take 100 houses and monitor the average concentration in those houses over the course of 24 months. Pair match 50 pairs, and install counter tops and measure the radon concentrations for 24 months. Do the math. Why hasn’t this been done? Because the costs aren’t justified, because the risks aren’t there.

Actually, I know of no completed studies at all that have tested individual homes. Build Clean is doing one in Houston, but are focusing on Quartz and granite tops already installed. They aren't planning on taking the countertops out! The Radon levels in Houston are usually near zero because of the soil types, so checking a nearby home without a granite or quartz top will serve as a control. Your arguement seems to be since these studies haven't been done, it isn't possible for granite to contribute to the indoor Radon levels. Doing a test like that, installing or removing $5,000 countertops, would be cost prohibitive would it not? Saying it hasn't been done because the risk isn't there is not logical.

Three tops have already been removed, two Shivikasi and one Bordeaux. All three kitchens had very high level Radon, up to 14 pCi/L untill the tops were removed. The homes returned to normal levels afterward.

That is fact, and the conclusions are apparent.

One might as well lie awake at night worrying about whether green seatbelts are safer than black seatbelts.

Cheers!
Caoimhín P. Connell
Forensic Industrial Hygienist
Forensic Industrial Hygiene

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

AMDG

Al Gerhart · #16 (**permalink**) 06-09-2008, 05:17 PM

Jerry,
What type of stone is being used as flooring in the cases you mention? If it is granite, it seems that even more concern for testing would be the case.

I hope you guys get paid a lot more for those monster sized homes you inspect. I bet it takes some time to do a though job.

Anybody know that inspector that does the syndicated column in the Real Estate sections of local papers? I forget his name at the moment. Is he the real deal?

Thanks for the input, you got me thinking,
Al

John Arnold · #17 (**permalink**) 06-09-2008, 05:21 PM

I'm not Caoimhin and I don't play him on IN, but here is some radon info from his website:

Radon: Risk and Reality