Episode 5: Artificial Stone vs. Natural Stone
James Nevin: Hello everyone. Welcome back to another episode of From Dust to Verdict. I'm your host, James Nevin, a partner at the law firm of Brayton Purcell LLP. This podcast is dedicated to the epidemic of accelerated silicosis and artificial stone countertop fabrication workers. In each episode, we explore important topics and issues about this occupational health epidemic as well as the associated lawsuits.
Today in Episode 5, we will discuss exactly why artificial stone is so much more hazardous to fabrication workers than natural stone. So in order to understand this, first we have to refer back to the hierarchy of controls from NIOSH, the inverse upside down pyramid. It starts with elimination and substitution at the top is the best methods to protect workers, followed by engineering controls, administrative controls, and then personal protective equipment.
And we've discussed in past episodes why these controls work pretty darn well for Natural Stone. Today we're going to take a deep dive into the scientific reasons of why the hierarchy of controls work reasonably well for natural stone, but aren't effective at preventing accelerated silicosis and other disease when it comes to artificial stone.
And so when it comes down to it -- to a consumer or anyone else who's not a artificial stone fabrication worker, not in the industry -- stone slabs look the same to us, right? We see them on a finished countertop. The stone slab looks the same regardless of what it's made from. In fact, not all stone slabs are created equal, and this is because when it comes down to it, the silica that is in these slabs is in fact not all the same.
So we know this from a large body of global published peer reviewed literature. Most importantly are several studies from Dr. Ramkissoon in Australia and Dr. Qi from NIOSH. So most significantly, Dr. Ramkissoon in Australia has published numerous articles. The most significant ones are an article for each of the last four years, an article from 2002, from 2023, from 2024, from 2025.
Each focused on the characteristics of artificial stone and the dust that it produces in comparison to natural stone. Now referring to Dr. Qi at NIOSH, he has done similar studies, not just looking at the constituents of the artificial stone, but also how the various engineering control methods work with different types of artificial stone and natural stone in terms of keeping or trying to keep the levels of dust below the PEL or permissible exposure level.
And so Dr. Qi has done a whole series of studies over many years, and here are some of them. So first of all, as we can see here from Dr. Qi, he's looking at various engineering and administrative controls, most importantly, focused on water. So the first column is water spray alone, and you notice that his levels are at 300.
Keep in mind that the PEL is 50 and the action level is 25. So showing that water spray alone is not an effective method of keeping the dust from artificial stone below the PEL. His next column is water spray plus sheet wetting, and he gets it down to 123, still far above the PEL. And finally, water spray plus improved ventilation and housekeeping at 71, notably still above the 50 PEL and 25 action.
Now here we see further efforts to apply engineering controls and comparing ventilation with no ventilation and with improved ventilation. And notably with the best scenario, able to get the levels reduced significantly lower, still above the PEL. Notably, they found that the most effective method, still not perfect, but the most effective method at keeping the levels relatively reduced, where this method where they essentially flooded the slab with water.
This method doesn't actually exist. It's not any mechanism that's sold even today. And is quite difficult to do if you think from a practical level because it requires an intensive amount of water constantly flooding the slabs. So to understand the results of Dr. Ramkissoon and Dr. Qi, we need to actually look at the underlying components of artificial stone versus natural stone and artificial stone, high content silica versus low content silica, artificial stone.
So the first thing to understand is that natural stone does contain silica and at varying levels, depending on the type of natural stone. So for example, marble contains less than 5% silica, granite contains less than 45% silica as compared to high content artificial stone, which is 90 to 95% silica.
However, there are certain natural stones that do contain high content silica. For example, quartzite is a natural stone that contains around 90% silica.
So the high Kenton silica is not the only issue. So while it's not the only issue, it is an important issue. And so, for example, if we look at Dr. Qi’s findings -- in this slide, he's comparing high silica content artificial stone, to mid content artificial stone, to granite, which is a natural stone, and to recycle glass or so-called no silica artificial stone.
And so he's finding a significantly higher amount of respirable crystal and silica in the dust from the high silica artificial stone compared to the mid-level content silica artificial stone, which is roughly the same as the granite. And then all of those are significantly more than the recycled glass supposed no silica content artificial stone.
So just looking at the level of respirable crystal and silica produced from the stone when it's cutting, we see rather obviously compared to the content, is that the highest content artificial stone is going to produce the most silica dust. And the reduced content artificial stone and natural stone is going to produce a mid-level of silica dust. And the no content artificial stone is going to produce almost no silica dust.
So content is the first factor. The second factor is the size of the silica being produced. And to give you context, think about the size of salt, table salt, common table salt, which is about a hundred microns, okay? To actually be able to inhale a particle and have it be respirable down into your lungs, the largest that can be is 10 microns.
So one 10th the size of one table salt grain to be able to even breathe it into your lungs in the first place. Another way to think about it is that one human hair is about 50 microns. And again, for something to be breathable, respirable into the lungs, it has to be smaller than 10 microns.
So now keep in mind that 10 microns is actually still quite relatively large when it comes to our lungs and breathing. We get down to what's called ultra fine particles at 0.1 microns, and even those are still larger than the typical silica dust produced from artificial stone, which is one, typically, one 100th or smaller of 0.1 microns, nano-sized.
So when artificial stone is made, it's made with quartz, which is a natural stone that's mined out of the ground, but then it is crushed and pulverized to nano size before it is then mixed in with the other ingredients to make the artificial stone.
So the end result is that the silica particles that are in artificial stone are so much smaller than the silica particles that are in natural stone. And when it comes to breathing, the smaller it is, the worse it is for you because your body's defense mechanisms are pretty good at stopping large particles from getting through.
It's the small stuff that gets through that gets through the mask, that gets through your throat, that get through your bronchial defense mechanisms and causes disease. And so that's the second factor that we know from Dr. Qi, Dr. Ramkissoon, and many other published peer reviewed authors around the world on why artificial stone as compared to natural stone or no content, artificial stone is causing such accelerated silicosis.
So the first factor was the high content in artificial stone of the silica. The second factor is the nano size of that silica in artificial stone. Whereas compared to, say, natural stone, for example. So for example, quartzite like artificial stone has very high content silica. However, the size of the silica in quartzite is humongous compared to the size of the silica in artificial stone.
So the third factor that we know from these published peer reviewed studies is the other components of artificial stone. So the other components of artificial stone -- so if we're talking high content, artificial stone, the other five to 10% of the ingredients are metals, aluminums, copper, iron, magnesium, and various volatile organic compounds, otherwise known as toxins.
So these toxins and metals combine with the silica and artificial stone to cause disease. And so what Dr. Ramkissoon is finding is that in artificial stone, the other ingredients, the volatile organic compounds, the metals are often coating the silica dust that is released during fabrication.
And so, if you can think of an analogy, it's kind of like throwing gasoline on a fire. Like the only thing worse than a toxin and a carcinogen is combining it with another toxin and carcinogen. And controversially, Dr. Ramkissoon finds that in the non artificial stone, the silica that is released -- and again, it's not as small, it's much larger -- it often is coated with relatively benign other constituents of natural stone.
In other words, the silica released from natural stone is lower in content typically, but even with something like quartzite where it's higher high in content, just like artificial stone, it's smaller in size than the nano size artificial stone. And often it's coated with something that is benign, that is non-toxic to the body because natural stone contains more than just silica, it contains other natural components.
And so those natural components Dr. Ramkissoon found are essentially coding and developing that otherwise toxic silica particle. And so these three reasons: high content nano size and the other toxins and carcinogens in artificial stone as compared to natural stone or mid content artificial stone or no silica content artificial stone, show us why the high content artificial stone is causing so much accelerated silicosis and other diseases and fabrication workers, when we haven't seen that level of disease in workers before.
Another way of saying it, is the process of stone fabrication has been around for a very long time, and that process hasn't changed, and it's gradually improved over the years with better safety mechanisms, with, you know, masks and what equipment and so forth.
And people like Dr. Qi at NIOSH and many others around the world have published peer reviewed studies showing that those mechanisms work and have worked and worked for decades reasonably well in keeping fabrication workers, safe, relatively safe from disease that we did not see a tip very much silicosis in fabrication workers until something changed.
What changed? The artificial stone slab manufacturers introduced this artificial stone product into the existing market. And so, fabrication workers went from fabricating natural stone to fabricating this artificial stone with no warnings that this was something different. And in fact, being told up through today by the slab manufacturers that the various engineering and administrative control mechanisms recommended for natural stone, they're being falsely told that those mechanisms work with artificial stone.
But we know from the studies of Dr. Qi, Dr. Ramkissoon, and many others throughout the world, that in fact, when they actually are looking at these methods under a microscope, and looking at the dust that's produced, and looking what's in the dust. and looking at the amount of the dust -- we see, they see, that the levels of dust produced even when using these protective methods when fabricating artificial stone are still far above the PEL.
And then what is in the dust is so significantly much more dangerous for the workers in the first place.
Thank you for turning into this episode of From Dust Verdict. I'm your host, James Nevin, from the law firm of Brayton Purcell, LLP. Remember to like and subscribe, and for anyone that speaks Spanish, I encourage you to check out the Spanish language version of this podcast hosted by my good friend, Charley Velasco Ariza. Thank you.
