Silica Hazards from Engineered Stone Countertops

Posted on by Karen Worthington, MS, RN, COHN-S; Margaret Filios, SM, RN; Mary Jo Reilly, MS; Robert Harrison, MD, MPH; and Kenneth D. Rosenman, MD

A new engineered stone countertop product known as “quartz surfacing,” was created in the late 1980s by combining quartz aggregate with resins to create a product for use in home building and home improvement.  Manufacturing of this material, including products such as CaesarStone™, Silestone™, Zodiaq™, or Cambria™ is a fast growing industry.  First made in Israel and Spain, production of these materials has grown world-wide, driving quartz slab imports to the U.S. up 63% between 2011 and 2012 and 48% between April 2012 and April 2013 (Schwartzkopf 2013, StatWatch 2013).  Quartz surfacing materials may contain up to 93% crystalline silica (Dupont 2010).  In contrast, the percent of crystalline silica in a slab of granite is less than 45%, darker color granite has a lower percentage (Simcox et al. 1999).  Workers who fabricate and install quartz surfacing are at risk for overexposure to silica released during sizing, cutting, grinding and polishing.  Prolonged inhalation of dust from silica-containing materials can lead to silicosis (scarring of the lungs).  In addition to silicosis, scientific evidence indicates that occupational exposure to crystalline silica puts workers at increased risk for  other serious health conditions: chronic obstructive lung disease, lung cancer, kidney and connective tissue disease, and tuberculosis.  The focus of this blog is on silicosis, which has occurred in multiple workers in this industry.


Silicosis is caused by breathing in very fine (“respirable”) dust containing crystalline silica. Initially, individuals may be developing disease even without respiratory symptoms. Chronic silicosis typically develops over 10 or more years of exposure to low levels of respirable crystalline silica. However, high levels of exposure can cause faster development of the disease. The diagnosis is usually made through a chest radiograph, which should be classified by a NIOSH-certified Reader.

Cases of silicosis have been reported among engineered stone countertop workers in other countries.  In a study published in 2012, researchers in Israel found 25 patients referred to their National Lung Transplantation Program with silicosis who shared a common exposure history. All had worked with the same commercial brand of decorative quartz surfacing material for 10–14 years and performed similar dry-cutting of the material for kitchens and other countertop applications (Kramer et al. 2012).  Most recently, 46 cases of silicosis were reported in Spain in workers cutting and installing engineered stone countertops with silica content of 70-90% (Pérez-Alonso et al. 2014).  These individuals were young (ages 29–37 years) and worked in the industry for 9–17 years.

While no reported cases of silicosis  in the U.S. have been linked to quartz surfacing materials, recent research indicates that exposures to silica-containing dust while working with these materials may approach or exceed the Occupational Safety and Health Administration (OSHA) current Permissible Exposure Limit (PEL) (Phillips et al. 2013).  Multiple inspections by OSHA (U.S. Department of Labor) have documented overexposures to silica at stone fabrication shops working with a combination of natural stone and quartz surfacing materials (OSHA 2011).  These overexposures would indicate U.S. workers in this industry are at risk of developing silicosis as well as the other multiple health conditions associated with silica exposure.

Protecting Workers

We can apply what we know about reducing exposure to dusts from natural stone products to quartz surfacing materials.  The key to prevention is keeping dust out of the air.  Hazard alerts published in California and Washington State described exposure to silica dust and other hazards related to fabrication of granite and natural stone products and provided dust control recommendations.  Whenever possible, cutting, grinding and shaping should be done wet.  Ventilation and filtration systems should be used to collect silica-containing dust at its source.  If these engineering controls fail to eliminate the risk, then use of at least a NIOSH-approved N95 respirator is recommended.

In addition to information and resources on silica and silicosis for employers and employees provided by NIOSH and OSHA, the Center for Construction Research and Training’s website “Work Safely with Silica” is searchable by work task, material and tool.

Help Wanted

There is relatively little sampling data available on quartz surfacing materials. NIOSH encourages fabricators to submit a request for a Health Hazard Evaluation (HHE).  More information can be found on the HHE Topic Page.  Researchers at NIOSH are especially interested in seeing  a state-of-the-art engineered stone countertop manufacturing facility to help us understand how to best control exposures to quartz surfacing material.  If you are interested in working with NIOSH, you can contact us using the comment section below, e-mail us at, or submit an HHE at the link provided above.

Finally, if individuals working with countertops have health problems or are concerned about past exposures, they should see a healthcare provider and inform them about their concerns. Healthcare providers who suspect that their patients’ health problems may be caused by working with quartz-containing materials are encouraged to report their concern to their state health department.

Web Pages of Interest


Click here for the references used in this blog entry.

Karen Worthington, MS, RN, COHN-S; Margaret Filios, M.Sc.; RN; Mary Jo Reilly, MS; Robert Harrison, MD, MPH; and Kenneth D. Rosenman, MD.

Karen Worthington is a Research Scientist in the New Jersey Department of Health and Senior Services.

Capt. Filios is a Senior Scientist in the NIOSH Division of Respiratory Disease Studies.

Mary Jo Reilly is an Epidemiologist in the Division of Occupational & Environmental Medicine at Michigan State University.

Dr. Harrison is a Professor of Medicine at UC San Francisco and Chief of the Occupational Health Surveillance and Evaluation Program at the California Department of Public Health.

Dr. Rosenman is a Professor of Medicine and Chief of the Division of Occupational and Environmental Medicine at Michigan State University.

Posted on by Karen Worthington, MS, RN, COHN-S; Margaret Filios, SM, RN; Mary Jo Reilly, MS; Robert Harrison, MD, MPH; and Kenneth D. Rosenman, MD

54 comments on “Silica Hazards from Engineered Stone Countertops”

Comments listed below are posted by individuals not associated with CDC, unless otherwise stated. These comments do not represent the official views of CDC, and CDC does not guarantee that any information posted by individuals on this site is correct, and disclaims any liability for any loss or damage resulting from reliance on any such information. Read more about our comment policy ».

    I am an architect and I am always eager to see the creativity of others, relevant article.

    This is important information since it draws attention to a silica exposure hazard. I am concerned that the term “engineered stone” does not warn workers about the potential silica exposure. Maybe “engineered silica stone” or “engineered quartz counter top” would be better…. Descriptive terminology in this case appears to be critical.

    Karen Worthington, Margaret Filios, Mary Jo Reilly, Robert Harrison and Kenneth D. Rosenman says:

    Thank you for your comment. As this is a relatively new product, the terminology is still evolving. At present, “quartz surfacing materials” appears to be the term preferred within the industry. As we continue to work in this area we can help refine the terminology used by safety and health professionals.

    This has been very interesting and informative. Here is my stupid question now.
    I have a quartz composite sinks in my kitchen and butlers pantry. Quartz for my kitchen counters and granite on my island. My house is new, so I’m assuming everything has been sealed. What are the concerns I should have of silica dust if any?

    Thank you for your comment. Living with stone countertops will not cause silicosis. The hazards we described occur from installation workers’ exposure to inhaled dust that is created during installation from cutting, grinding, and polishing the raw materials. You are unlikely to generate inhalable dust from the engineered stone material, quartz, or granite during general use as a household surface.

    Great article! We (OSHA) actually found worker silica exposures (via personal sampling) to be 50% of the OSHA PEL during stone cutting and polishing work under very wet operating conditions (no local exhaust used). The product was either Silestone™ or Zodiaq.

    Really helpful and informative piece! Impressed a lot and i’m really willing to read something more from your side. Keep posting!

    I am very interested in this topic in this industry. I have created a device that reduces exposures to silica in these shops. For my final report for my master’s degree I explained ways to reduce silica exposures in marble and granite shops. I tested it in four shops and reduced exposures in all the shops below the OSHA-PEl. When used correctly with fans strategically placed it works even better. With or without my screen I am very interested in working on this. I have a lot of experience with M & G shops and would like to share my thoughts and data.

    Good afternoon Stu, my name is Randy and my brother and I own a fabrication shop in Jacksonville Florida. Working a lot these days with Caesarstone and would like to find out more information about your screen and your methods to reduce silica exposure, where can I find out more information on your methods?

    The workers should be aware of these hazards they expose themselves to. It will also help if the workers would get an early retirement package so they can healthily enjoy their golden years. There is a limit for our body’s tolerance to such work especially when we reach the age 55. Having that kind of nature for a job does something to your body over a period of time. Well, I guess it also depends on the healthcare you get.

    Myself Anshul Mishra, I want to add one important thing here that in production process we use resin and chemicals for thermo-chemical reaction of resin with quartz material. So styrin gas evaporate, this gas affect our central nervous system. It is quit harmful.

    Karen Worthington, Margaret Filios, Mary Jo Reilly, Robert Harrison and Kenneth D. Rosenman says:

    Thank you for your important comment. Although this blog article addressed fabrication shops as the work setting of concern, you raise a very important issue regarding potential airborne chemical hazards, including styrene, which may be present during the manufacturing process. Both the U.S. occupational health and safety research agency (NIOSH) and enforcement agency (OSHA) are further investigating the hazards associated with these engineered stone products.

    NIOSH welcomes Health Hazard Evaluation requests from U.S. employers or employees involved in manufacturing engineered stone countertops (see link on blog site). NIOSH health and safety experts would view work processes and practices, assess exposures and health, and recommend ways to reduce all occupational hazards.

    healthy worker is very important, safety first must be.
    This is my first visit to your blog, I get a lot of useful information here. Thank You

    best regard

    Interesting article on the link between building stone and silicosis. Quartz is a very type of popular stone for residential customers. Combing quartz aggregate into an attractive mixed coloured aggregate and then the cutting of the stone does produce an enormous amount of dust. But causing silicosis, provides installers with the need to take precautions for it’s installation.

    For an architect the blog is really helpful. Impressed a lot and I’m really willing to read something more from your side. Carry on your discussion. Keep posting!

    In Spain, where quartz surfaces have been very popular for more that a decade, we are
    now having an epidemic of silicosis among shop workers.

    I would like to speak to a NIOSH contact person regarding a project we are starting on counter top shops.

    Another great article. We at [name removed] were thinking of expanding our business to provide stone countertops as well. Meanwhile we heard of silicosis epidemic that had spreaded among workers in a local company and to be honest, we did not pay enough attention regarding the problem until we stumbled upon your article. We never really had any idea how harmful this could be. More people should read this.

    I am trying to find out what is OSHA recommended or better mask to use in fabrication of the quartz counter top

    Another great article. We at [name removed] were thinking of expanding our business to provide stone countertops as well

    The description of Building stone and silicosis is really interesting .my first visit to your blog is very usefull.Keep updating.

    OSHA is the Occupational Safety and Health Administration. It is located in the Department of Labor and develops and enforces workplace safety and health regulations. . OSHA and the National Institute for Occupational Safety and Health (NIOSH) were both created under the Occupational Safety and Health Act with different but complementary missions. NIOSH, which is located in the Department of Health and Human Services, is the U.S. federal agency that conducts research and makes recommendations to prevent worker injury and illness.

    I found your article very interesting. I am looking for verification of the percentage of quartz particles vs. polymers that make up quartz surfaces. You mention that quartz surfacing contains “93% crystaline Silica”, with the other 7% presumably made up of some type of polymer resin. I used to have a geologist on staff who claimed that compacting particulates to 93% volume was physically impossible. Even with well distributed particles or specifically shaped particles, the “tightest” density of particle compaction would be about 75%. He postulated that when they refer to 93% quartz particles, they would be referring to percentage by WEIGHT, not by volume. Do you have any resources that could either confirm or dispel this proposition?

    On another note, our company was served notice back in 2003 from our workers comp insurance carrier that the reinsurance company they were using was not going to provide re-insurance (catastrophic) for any company that was in an industry where there was opportunity for free silica dust to be present in the work environment, including granite fabricators, sandblast operations, sand & gravel operations, etc. We had to go through a 21 day monitoring exercise in our shop to prove that the wet cutting and wet grinding/polishing methods used did not produce air borne silicates. I can say with confidence that any shop using wet methods for cutting and polishing, coupled with typical PPE diminishes any risk of silicosis to negligible levels. Most of today’s granite fabricators use wet finishing and wet cutting methods.

    Any help on the aggregate compaction question would be great. Keep up the good work!

    Very good read ! Even already knowing the effects of working with engineered stone is no good for your health unless you use the proper PPE (Personal Protective Equipment) I even believe doing it wet though that the water vapor is worse for you ? I prefer working with natural stone any day . Worked with other stonemasons very careless and neglectful to their own health and others . Great looking product but prefer to avoid working with it . At the end of the day do what’s important for health , family and others take all precautions and with progression of technology health and safety will get better for future stonemasons and installation contractors . SAFETY FIRST ! Don’t take short cuts ?

    100 cases of Silicosis in the whole of America! How many die from smoking every year? Worksafe New Zealand are pushing a campaign around silica dust even though there are no cases or perhaps one or two in a bad year. There are 5000 deaths from smoking.
    I think a campaign targeting COPD and general workplace dusts, fumes and chemicals would make more sense.

    I work on this issue in Italy, and my concern is the Installers of porcelain stoneware.
    In this kind of final product usually the amount of quartz is around 15-20%.
    Have you evaluate the exposure of workers while cutting the tiles for the floor or wall?
    Thank you for all the information I can find in your site.

    Those people working in dangerous or hazardous environment shouldn’t stick on the job for many years because of the exposure to these harmful substances.

    What happens when engineered Quartz is heated? I recently had large pieces of quartz installed as a fireplace surround. I feared that my fatigue could have been caused by the Quartz which gets pretty hot when the fireplace is on. The fireplace is see-through gas powered.

    Karen Worthington, Margaret Filios, Mary Jo Reilly, Robert Harrison and Kenneth D. Rosenman says:

    Thank you for your question. We are unaware of research evaluating emissions from engineered quartz products heated in the way that you have described. We suggest that you contact the manufacturer. Also, we welcome comments from other readers of the blog if they have information about this topic.

    Granite countertop installed. No safety precautions used.Teck dry sanded backslashes and small areas of concern. We were not aware of the danger of the dust which was now everywhere. Did not washout cabinets,dishes etc.We wiped down things with dry cloth and used regular vacuum to clean up.Two months later after family and friends found out and educating ourselves I am concerned for our health.Should I be?

    Karen Worthington, Margaret Filios, Mary Jo Reilly, Robert Harrison and Kenneth D. Rosenman says:

    Thank you for your comment. This blog discusses the hazards of engineered stone which is different from granite, although granite is known to contain crystalline silica. The earliest studies in the United States on silicosis were done among granite shed workers. The risks for getting silicosis and other silica-related disease depends on the duration and intensity of exposure to dust that contains crystalline silica. A homeowner’s exposure from residual dust following a granite countertop installation would not likely deliver a dose large enough to cause disease. The exposures faced by workers, especially those who do not use dust controls and personal protective equipment, and who are cutting and sanding material repeatedly during their working life do face significant risk from their accumulated exposure. If you have further concerns about the dust in your home, you should contact your local board of health or Department of Environmental Protection.

    For an architect the blog is really helpful. Impressed a lot and I’m really willing to read something more from your side. Carry on your discussion. Keep posting!

    Hello, i have been very nervous. I did not know how dangerous cutting granite was. I dry cut with a circular saw with diamond blade in a garage with the doors shut for about 3 hours ( i did open the doors between cuts). It was late and i did not want to wake my neighbors. I have been coughing for over 3 weeks now. I have read everywhere that granite has average of 70 percwnt silica? Is this true.. It was a dark brown granite so I hope that makes my situation better. I cant find much on silica content level on darker colors. It is novemeber in ohio and dry air with alot of coughing going around so im hoping its just a coincidence. I have been told a single exposure shouldn’t be enough to cause silicosis but i have read mixed messages. Any help i can get as i am very worried.

    Thank you for reaching out to us. We are very sorry to hear about your cough. There are many things that can cause a cough that persists for 3 weeks or longer. Common examples of lung conditions include asthma, bronchitis, or cough after a viral upper respiratory tract infection. Chronic sinusitis and gastroesophageal reflux can also contribute to chronic cough. There are also other less common causes.

    Granites from different geographic areas vary in their crystalline silica (quartz) content between 10 to 50%; the only way to know for sure is to have the granite analyzed by a trained geologist or mineralogist. However, acute silicosis is rare in this country and happens after massive exposure. It is unlikely that your single exposure would cause silicosis regardless of the silica content of the granite that you cut. However, it is possible that your uncontrolled dust exposure played a role in setting off your symptoms. If your cough remains troublesome, or if you have other respiratory symptoms that are troublesome, we strongly recommend that you see your personal physician for evaluation and treatment.

    I have rental property across the street from a fabricator , I cant do work there because of the dust in the air!

    What a great post about Stone Countertops. Excellent post. I want to thank you for this informative read.

    Does this silica exposure affect household members on prolonged exposure ? I am just wondering 10-15 years of it in kitchen surface is good enough exposure to be worried about . Also any idea about the resin used for binding ? I read it has a few carcinogens !

    Thank you for your comment. Living with stone countertops will not cause silicosis. The hazards we described occur from installation workers’ exposure to inhaled dust that is created during installation from cutting, grinding, and polishing the raw materials. You are unlikely to generate inhalable dust from the engineered stone material during general use as a household surface.

    Resins used in the manufacturing of engineered stone countertops are polymerized (hardened) in the product and are unlikely to generate health effects once installed.

    We have recently uncovered an epidemic of advanced complex silicosis in counter top workers here in Australia. Many are young, some as young as 20 years. Measured levels during dry operations were as high as 20x the PEL. Very tragic.

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