California public health researchers have now confirmed 592 cases of silicosis among workers who cut and finish engineered stone countertops, including 31 deaths and 65 patients who required lung transplants, according to the report in NEJM Evidence published through the Public Health Alerts collaboration between that journal and the University of Minnesota's Center for Infectious Disease Research and Policy.
Silicosis is incurable. Scar tissue in the lungs does not reverse, and there is no treatment that restores lost function. The disease has historically taken decades of exposure to develop in miners and sandblasters, which is what makes the pattern in these workers so unusual.
The median age at diagnosis in this group was 46. The mean age at death was 52. All but one of the patients was male, and 580 of the 592, or 98 percent, were Latino.
From One 32-Year-Old Patient to a Statewide Count
The California Department of Public Health identified the first case in January 2019. The patient was a 32-year-old countertop worker who died of respiratory failure at 38.
Investigators then confirmed two more cases at the same company, one of which also proved fatal. When they screened the company's 43 employees, they found five additional cases of silicosis. That single workplace produced eight identified patients.
Through June of this year, statewide surveillance had confirmed 592 cases tied to engineered stone fabrication. The report, summarized by CIDRAP, describes the cases as notable for the patients' young age at diagnosis, short duration of exposure, severity and rapid progression of disease, and frequent co-occurrence of other silica-associated conditions including autoimmune disease and tuberculosis.
Engineered Stone Carries Far More Silica Than Granite
The material itself is the reason. Engineered stone slabs, sold to homeowners as quartz countertops, are made by crushing natural quartz into fine powder and binding it with polyester resins and pigments. The finished product typically contains more than 90 percent crystalline silica.
Granite, by comparison, generally contains less than 45 percent. Federal occupational health researchers have documented that difference for years, and a NIOSH analysis of engineered stone countertop exposures noted that quartz surface imports to the United States rose roughly 800 percent between 2010 and 2018 as the material became a default choice in kitchen remodels. It is now the most popular countertop material in the country.
Cutting, grinding, drilling and polishing those slabs releases respirable crystalline silica along with volatile organic compounds and metals. The particles are small enough to reach deep into lung tissue, where they cause permanent scarring.
The report's authors write that fabrication workers cutting, grinding and polishing these slabs can be exposed to hazardous levels of respirable crystalline silica. Silica dust exposure is also linked to lung cancer, chronic obstructive pulmonary disease, kidney disease and autoimmune disorders, according to the California Department of Public Health.
The Workforce Absorbing Almost All of the Harm
The demographic concentration in these cases is not incidental. Countertop fabrication in California is largely performed in small shops by immigrant workers, and the 98 percent Latino share of confirmed cases reflects who does this work.
Small shops are also where dust controls are least likely to be installed and maintained. The equipment that suppresses silica dust, meaning water-fed tools and engineered ventilation systems, requires capital to purchase and ongoing attention to keep working.
Language barriers, immigration status and the structure of small shop employment all reduce the likelihood that a worker raises a safety concern or seeks medical care early. Silicosis in its early stages often produces only cough, fatigue, or shortness of breath, symptoms easily attributed to something else.
Consumers are not at risk from a finished countertop already installed in a kitchen. The hazard is confined to fabrication and installation, where the material is being cut. Homeowners planning a remodel who want to reduce demand for hazardous work can ask a fabricator whether the shop uses wet cutting methods and local exhaust ventilation.
Rules Exist, but Enforcement Remains the Weak Link
California strengthened its silica regulations in 2023 after the earlier wave of cases was documented. The report's authors state plainly that stone countertop workers remain at risk despite those rules.
Their explanation is direct. Although silicosis is preventable by reducing or eliminating silica dust exposure, they write, the water-based tools and ventilation systems required to control the dust are costly to install and maintain, and overexposures can occur even with recommended controls in place. They add that enforcement of existing regulations is challenging.
That is an accountability finding as much as a clinical one. A state that wrote stricter rules is still counting new patients, which points to inspection capacity and small shop compliance rather than to a gap in the standard itself. The Western Occupational and Environmental Medical Association has since petitioned California's occupational safety board to prohibit fabrication and installation of engineered stone containing more than 1 percent crystalline silica.
The state maintains an engineered stone silicosis surveillance dashboard, so the confirmed count will continue rising as new cases are reported and investigated. Similar cases have been documented in other states and in Australia, which banned the manufacture, supply and installation of engineered stone in 2024, and researchers expect the American case count to be an undercount given how often early silicosis goes undiagnosed.
The undercount problem is structural. Surveillance depends on a clinician recognizing the pattern, asking about occupation, and reporting the case to the state. A worker who leaves the industry, changes states, or never seeks care for a cough does not appear in the numbers at all, which means the 592 confirmed cases describe the visible portion of a larger group.
Current or former fabrication workers with persistent cough, shortness of breath, or chest pain should tell a clinician specifically about their work history with engineered stone, since chest imaging and occupational history are what lead to diagnosis. Workers concerned about exposure can contact the California Department of Public Health's occupational health program, and California workers' compensation covers eligible workers regardless of immigration status.
Screening matters because early silicosis is often silent. In the first identified workplace, five additional cases surfaced only because investigators screened every employee rather than waiting for workers to report symptoms. That is the intervention with the clearest track record in this outbreak so far.
Key Questions Answered
What was reported? California researchers confirmed 592 cases of silicosis among engineered stone countertop fabrication workers through June of this year, including 31 deaths and 65 lung transplants.
Why is engineered stone more dangerous than granite? Engineered stone typically contains more than 90 percent crystalline silica, compared with less than 45 percent in granite. Cutting and polishing it releases far more respirable silica dust.
Are homeowners with quartz countertops at risk? No. The hazard occurs during cutting, grinding, and polishing. A finished, installed countertop does not release silica dust.
Who is getting sick? Almost entirely male fabrication workers, with 98 percent of confirmed California cases occurring in Latino workers. The median age at diagnosis was 46.
Is silicosis treatable? No. Lung scarring from silica is permanent and can progress. Some patients require lung transplantation. Silica exposure also raises risk of lung cancer, COPD, kidney disease and autoimmune conditions.
What symptoms should a worker watch for? Cough, fatigue, shortness of breath or chest pain. Anyone with these symptoms and a history of engineered stone work should mention that work history to a clinician directly.
Did regulation solve the problem? Not yet. California strengthened silica rules in 2023, but the report's authors say workers remain at risk because dust controls are expensive to maintain and enforcement is difficult.
