Hidden in Plain Sight: The Legacy Hazard of Artificial Stone in the Built Environment

A Hazard in an Ordinary Neighborhood

In August 2026, a California study published in NEJM Evidence documented 592 cases of silicosis among workers fabricating engineered-stone countertops. The following month, Cal/OSHA released a proposal to reduce silica exposure from artificial stone. Consequently, I began paying closer attention to residential construction and remodeling in the blocks around my home in San Francisco.

On October 12 and 13, I observed workers cutting or handling countertop material that appeared to be artificial stone. The work produced visible dust. I did not verify the material’s composition or measure respirable crystalline silica.

What I saw raised a question that extends beyond the fabrication shop: What happens to the silica hazard when artificial stone becomes part of a home, office, or other building?

 

Residential countertop work in San Francisco on October 12, 2026. The material appeared to be artificial stone, but its composition was not independently confirmed, and respirable crystalline silica was not measured. Photograph by Esteban González Burchard, M.D., M.P.H. Image de-identified for privacy before publication.

The Hazard Does Not End With Installation

Artificial stone, also called engineered stone, is widely used for countertops and other surfaces in homes, offices, and commercial buildings. Traditional products can contain more than 90% crystalline silica. Cutting, drilling, grinding, or polishing these materials can generate respirable crystalline silica (RCS), which consists of particles small enough to penetrate deeply into the lungs.

The consequences of occupational exposure are now well documented. From January 2019 to June 2026, California identified 592 cases of silicosis among workers fabricating engineered-stone countertops. Of these cases, 65 workers underwent lung transplantation, and 31 died. The median age at diagnosis was 46 years.

These recognized cases may not capture the full disease burden among exposed workers.

The danger during fabrication is well established. Yet fabrication is only one stage in the material’s life. Once installed, a countertop may remain in a home, office, or medical facility for decades. It may later be cut to accommodate a new sink or fixture, refinished, repaired, or removed during renovation. The worker performing that job may have had no connection to the original fabrication or installation.

An intact countertop is not the inhalation hazard at issue. The hazard arises when silica-containing material is cut, ground, drilled, or otherwise disturbed, producing respirable dust.

Exposure Beyond the Fabrication Shop

Experimental studies show that handheld power tools used to cut or grind artificial stone can generate substantial levels of RCS. Wet methods and local exhaust ventilation can reduce exposure, although wetting alone does not necessarily eliminate it.

A 2025 study by McGowan and colleagues helps define the concern beyond the fabrication setting. The investigators examined RCS measurements from stone-countertop businesses across the United States. Of 13 personal exposure samples classified as installation work, four exceeded the federal OSHA permissible exposure limit of 50 micrograms per cubic meter, measured as an eight-hour time-weighted average.

The installation sample was small, so investigators could not determine whether the measurements came from residential remodeling or from previously installed countertops. Despite those limitations, the study shows that countertop installers can experience RCS exposures above occupational limits.

OSHA and NIOSH also recognize silica exposure during countertop installation in commercial and residential settings. Their updated 2026 guidance recommends performing as much fabrication and finishing as possible in controlled shop conditions and minimizing on-site dust-generating activities.

Cutting and grinding are not the only potential sources of exposure. Silica-containing dust can accumulate on floors, equipment, clothing, and work surfaces, then become airborne during cleaning or handling. Workers who collect remnants, move debris, clean work areas, or dispose of silica-containing waste may encounter dust generated during earlier fabrication. OSHA’s silica standards address housekeeping because dry sweeping, dry brushing, and compressed-air cleaning can contribute to exposure.

The Material Remains While the People Around It Change

Once a countertop is installed, the silica remains in the material. The people and information surrounding it can change completely. A home or office building may change owners or tenants. The original fabricator may no longer be involved or may be out of business. Product records may be lost. Years later, the worker asked to enlarge an opening, refinish an edge, or remove the countertop may have no practical way to determine how much crystalline silica it contains.

Construction and remodeling are highly decentralized. CPWR reports that from 2014 to 2023, about 91% of U.S. construction establishments with employees had fewer than 20 workers. Millions of self-employed contractors and other construction businesses also operate without payroll employees. Smaller establishments may differ in their access to occupational-safety resources and training.

The practical question is not simply whether information about a countertop reaches the worker who cuts, grinds, repairs, or removes it. That worker also needs training, equipment, exposure controls, and working conditions that enable the warning to be acted on. Information without the means to prevent exposure is insufficient.

The material remains while the people around it change.

The Warning Must Follow the Material

The legacy problem is not only one of exposure control. It is also one of hazard communication over time. A warning given to the original fabricator can be lost when the material is installed, when a property changes ownership or occupants, when records are lost, or when a different contractor returns years later to modify or remove the material.

The warning therefore needs to follow the material, not merely the original product or transaction. Artificial stone may start as a slab, become a countertop or other architectural surface, and later be cut, reshaped, reused, or repurposed as a functional or decorative object. A durable warning system should remain associated with silica-containing artificial stone throughout the material’s useful life, even if the material changes ownership, location, or function. Hazard communication should also address remnants, discarded pieces, and accumulated dust, because silica exposure does not necessarily disappear when artificial stone becomes waste. The product’s form may change, but the material’s composition remains the same.

A durable warning should clearly communicate, across languages and levels of technical training, that mechanically disturbing the material can generate hazardous respirable crystalline silica. Because artificial stone is manufactured, sold, and installed internationally, effective hazard communication should not depend solely on written language. Widely recognized hazard symbols demonstrate the value of immediate visual communication, although any specific symbol for artificial stone would need to be scientifically accurate and consistent with applicable hazard-communication standards.

The objective is straightforward: years after fabrication or installation, a worker preparing to cut, drill, grind, polish, repair, reshape, or remove the material should be able to recognize that it may contain substantial amounts of crystalline silica and that dust-generating work requires appropriate controls.

Prevention Should Follow the Hazard

Artificial-stone silicosis has already shown what can happen when workers are exposed to high levels of silica without effective prevention. That lesson comes primarily from fabrication, but the material does not stay in the fabrication shop. Large quantities of artificial stone containing crystalline silica have already been installed in homes, offices, medical facilities, and other buildings, where they may remain for decades. Future work may be performed by contractors and workers who had no role in the original fabrication or installation.

There is insufficient evidence to conclude that modifying previously installed artificial stone is causing a second epidemic of silicosis. We also lack reliable estimates of how often workers who modify older artificial-stone countertops are exposed, the magnitude of those exposures, and the resulting disease burden. These evidence gaps are important.

Exposure measurements during modification, repair, and removal in homes and commercial buildings would help define the risk. Equally important are practical methods for identifying silica-rich materials and for communicating the hazard long after the original installation.

Existing occupational-safety requirements provide an important foundation, but they only work when the hazard is recognized and appropriate protections reach the worksite. Prevention must follow the material.

For artificial stone already installed in homes, offices, and other buildings, two questions deserve attention:

1. Before a worker cuts, drills, grinds, polishes, repairs, or removes existing artificial stone, does that worker know what may be inside the stone?

2. Does that worker have what is needed to do the job safely?

 

References

1. Heinzerling A, Flattery J, Cummings KJ, et al. Silicosis among workers fabricating engineered stone (“quartz”) countertops in California, 2019-2026. NEJM Evidence. 2026;5(9). DOI: 10.1056/EVIDpha2600187.
2. McGowan CM, Cantley LF, Klein R, Redlich CA. Work practices and respirable crystalline silica exposures in stone countertop fabrication shops. American Journal of Industrial Medicine. 2025;68:973-987. DOI: 10.1002/ajim.70020.
3. NIOSH and OSHA. Worker Exposure to Silica during Countertop Manufacturing, Finishing, and Installation. DHHS (NIOSH) Publication No. 2026-101. February 2026.
4. CPWR, The Center for Construction Research and Training. Small Establishments in Construction: Employment, Injuries, and Training. Data Bulletin. April 2026.
5. California Code of Regulations, Title 8, §1532.3. Occupational Exposures to Respirable Crystalline Silica.
6. Occupational Safety and Health Administration. Hazard Communication Standard, 29 CFR §1910.1200, Appendix C: Allocation of Label Elements and Pictograms.
7. Occupational Safety and Health Administration. Respirable Crystalline Silica, 29 CFR §1910.1053. Housekeeping provisions.