The quartz countertop in an American kitchen is inert. Cutting one is not.
California public health investigators have now confirmed 592 cases of silicosis among workers who fabricate engineered stone countertops, according to a report published in NEJM Evidence by researchers at the California Department of Public Health and academic partners. Sixty-five of those workers have undergone lung transplantation. Thirty-one have died.
Silicosis is a progressive, incurable fibrotic lung disease caused by inhalation of respirable crystalline silica. There is no treatment that reverses it.
One Death Opened a File That Never Closed
The surveillance effort began with a single patient. In January 2019, CDPH identified a countertop worker who had started the job at 32 and died of respiratory failure at 38.
Investigators examined his workplace and confirmed two additional cases at the same company, one of which was also fatal. They then screened the company's 43 employees and found five more cases of silicosis.
Eight cases at one shop. That result reframed the problem from a tragedy into a surveillance question, and the department expanded its tracking.
The case count since then reads less like an outbreak curve and more like a rising tide. The state's tracking dashboard listed 259 confirmed cases in March 2025, including 15 deaths and 30 lung transplants. Through June 2026, the confirmed total reached 592, with 31 deaths and 65 transplants.
Some of that increase reflects better detection rather than new disease. California designated silicosis a reportable condition in 2025, which mechanically increases the number found. The authors caution that the true burden is likely higher because many workers remain undiagnosed or are diagnosed late.
Why This Stone Behaves Differently from Granite
The material is the reason this is a distinct occupational epidemic rather than an old hazard resurfacing.
Engineered stone, marketed as quartz, typically contains more than 90 percent crystalline silica. Cutting, grinding, drilling, and polishing release silica as respirable dust, and the concentration difference compared to natural stone results in far higher exposure per hour of the same work.
Classic silicosis, the kind seen in mining and sandblasting, typically develops after a decade or more of exposure. The pattern in these workers does not follow that script. The report authors describe 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."
The median age at diagnosis was 46. Earlier California case series found that affected workers were overwhelmingly young Latino immigrant men working in small fabrication shops, and that dust controls such as water suppression were frequently absent or inadequate.
Misdiagnosis compounds it. Patients with silicosis have often been initially diagnosed with bacterial pneumonia or tuberculosis, which delays recognition while exposure continues. Reporting on affected workers has documented the same pattern and traced the earliest modern alarm to Israeli physicians who began describing aggressive silicosis in young countertop workers in the late 1990s.
Regulation Arrived, and the Curve Kept Climbing
California has done more than any other state, which makes the trajectory harder to explain away.
The California Occupational Safety and Health Standards Board passed an emergency regulation in 2023 and made it permanent in early 2025, strengthening protections for workers exposed to silica dust from engineered stone. Outside California, there is no comparable statewide tracking.
The report authors state the outcome plainly: although surveillance findings have prompted regulatory and legislative changes in California, workers continue to be exposed to hazardous levels of respirable crystalline silica.
Part of the explanation is latency. People diagnosed today were exposed years ago, so current cases partly reflect a workforce from before the regulation. Part of it is enforcement reaching into small shops with limited resources, where workers may hesitate to report conditions. Two occupational health experts have argued that safer alternatives already exist, including surfaces made from amorphous silica, and that consumers are generally unaware of them.
David Michaels, professor in the Department of Environmental and Occupational Health at the George Washington University Milken Institute School of Public Health and former assistant secretary of labor for OSHA, co-authored the report, which the university announced this week. The authors call for a multifaceted approach, including clinicians identifying and reporting cases to public health authorities, improved surveillance by local and state jurisdictions, and policy change.
What This Means for Workers and for Homeowners
For homeowners, the distinction is important and reassuring. An installed countertop does not generate silica dust and poses no known respiratory hazard in a finished kitchen. The danger arises during fabrication and falls almost entirely on the people doing the cutting.
For anyone who has worked in countertop fabrication, the relevant fact is that silicosis can be present without symptoms in its early stages. Symptoms, when they appear, may include cough, fatigue, shortness of breath, or chest pain, and silica exposure also raises the risk of lung cancer, chronic obstructive pulmonary disease, and kidney disease.
Current and former fabrication workers who have not been screened should tell a clinician specifically about their work history with engineered stone, because that single detail changes what a doctor looks for. A summary of the report outlines the case characteristics that should raise suspicion, and California workers can find reporting guidance through the state's occupational health branch.
Key Questions Answered
How many cases has California confirmed?
592 cases of silicosis among engineered stone countertop fabrication workers between January 2019 and June 2026, including 65 lung transplants and 31 deaths.
Why is engineered stone more dangerous than natural stone?
It typically contains more than 90 percent crystalline silica, far more than most natural stone, so cutting, grinding and polishing it releases much higher concentrations of respirable silica dust.
How is this different from classic silicosis?
Cases are appearing at younger ages after shorter exposures, progressing faster, and occurring alongside other silica-associated conditions, including autoimmune disease and tuberculosis. The median age at diagnosis in California was 46.
Is an installed countertop dangerous?
No. A finished, installed countertop does not generate silica dust and poses no known respiratory hazard. The exposure happens during fabrication.
Has regulation reduced cases?
Not yet visible. California adopted an emergency regulation in 2023 and made it permanent in early 2025, but the report states that workers continue to be exposed to hazardous levels. Long latency means many current diagnoses reflect earlier exposure.
Why is the true number probably higher?
Because many workers remain undiagnosed or are diagnosed late, silicosis can be present without symptoms early on, and no comparable statewide tracking exists outside California.
What should a current or former fabrication worker do?
Tell a clinician specifically about your work history with engineered stone. That detail changes what a doctor looks for and can prompt appropriate imaging and lung function testing.
