California Quartz Stoppage Inches Closer to Reality
LOS ANGELES – A California workplace-safety commission took the first step last week here to possibly ban the future use of engineered stone in the Golden State.

The California Occupational Safety and Health Standards Board (COSHSB) voted 3-0 on May 21 to begin the process of changing the state’s workplace standards to stop the fabrication and installation of engineered stone containing more than 1% of crystalline silica.
The board directed CalOSHA, the state’s workplace-safety enforcement agency, to draft emergency standards and set up advisory committees on potential worker protections. The board set no timetable for delivery and consideration of the emergency rules.
The process mirrors the actions taken in late 2023 by the board to eventually ban dry cutting and setting specific procedures for working with engineered stone.
Last week’s action doesn’t include any natural stone, including quartzite, or other man-made surfaces such as porcelain.
The board officially granted the petition filed by the Western Occupational and Environmental Medical Association (WOEMA) last December that requested the board stop the use of engineered stone in California.
WOEMA, a multi-state organization of workplace-health physicians and others, requested the action due to increasing cases of workers contracting silicosis, an often-fatal lung disease, due to exposure to respirable crystalline silica (RCS).
At last week’s meeting, Dr. Betsy Noth, a senior industrial hygienist with CalOSHA, noted that the number of silicosis cases among artificial-stone workers “has increased ten-fold over the last three years.
“This means that the cumulative number of cases doubles approximately every 1.1 years, or 13 months. Assuming cases in 2026 continue to follow the same trend, the total cases will reach 900 by 2027.”
A presentation to the board noted that between 1968-2002, there were approximately six deaths per year nationwide with stone fabricators and related trades. Since 2019, there have been 31 deaths just in California attributed to silicosis by the state health department.
Noth also stated that dangerous crystalline-silica exposure is enhanced by incredibly small nanoparticles that can’t be measured by mass or weight. The standard used for small particulates — PM2.5, approximately 36 times smaller than a grain of sand – is ineffective in measuring nanoparticles.
“They’re too small to be to meaningfully measured by mass; a single PM2.5-sized silica particle weighs the same as a million nanoparticles,” Noth said, and previous measurements using permissible-exposure limit (PEL) figures “don’t take into account any changes in nanoparticles.”
Eric Berg, CalOSHA deputy chief of health, told the board that his agency “finds that the fabrication and installation of artificial stone with greater than 1% crystalline silica is inherently dangerous, highly toxic, and harmful to workers, and this should be prohibited.”
The day-long public hearing on the included more than 30 former and current fabrication-shop workers relating their major health problems after working with engineered stone. The board also heard from industrial hygienists, attorneys, and others supporting a fabrication/installation ban, including the California Medical Association.
Matt Thurston, Cosentino’s regional director for the western United States, told the board that CalOSHA and COSHSB staff reports “do not completely reflect the current state of science.
“Cosentino submitted an extensive independent scientific third-party analysis, and that record appears to have been overlooked, while some questionable reports from other sources have been heavily cited.”
He also noted that “many shops already use these products safely and legally.
“Banning a product to compensate for failed enforcement is irresponsible,” he added.
The board also heard from two lobbyists representing engineered-stone manufacturers and distributors.
Kirk Kimmelshue, representing the A.St.A group of 11 engineered-stone manufacturers, noted that board staff’s evaluation “admits that no economic analysis has been conducted to date to support the assertion in (WOEMA) Petition 609 that the requested action would not create significant economic consequences for fabrication businesses, their workers, and for California.”
He also cited a state auditor’s report from last year focusing on CalOSHA’s failure to maintain adequate enforcement staffing, limiting the agency’s ability to protect workers.
“A prohibition against the fabrication of any subset of silica-containing stone will be ineffective, because Cal OSHA cannot enforce it, and because even if enforced, workers will continue to be overexposed to RCS.”
Alicia Priego, appearing “on behalf of manufacturers and distributors,” asked that the board establishing a silica advisory committee and silica science subcommittees on the silicosis issue.
“We urge you to ensure that these committees are equitable, objective, and composed of individuals with relevant expertise, including epidemiologists and industrial hygienists,” she said. “In addition, we encourage the board to ensure that the scope of the requested research, scientific data, and questions under consideration remains objective and grounded in the most current evidence available.”
Andy Gerber, president of the Bricklayer and Allied Craftworkers Local 4 in LaVerne, Calif., read a letter to the board from both Northern and Southern locals of the union, along with the international union, supporting a “focused regulatory ban” that excluded cementious materials, and amorphous silica products, as well as natural stone and porcelain.
Gerber also noted the union advocates a narrow focus on countertop fabrication with the ban, and not on work performed on construction sites performed under federal OSHA standards.
However, Peter Dominguez, president of California Surfaces in Santa Fe Springs, Calif., told the board that exempting construction work may still lead to health problems.
“If jobsite cutting isn’t addressed, it creates a direct economic incentive for contractors to keep polishing in the field where there are none of the dust controls that a fabrication shop is required to have,” he said. “If quartz is banned in stone shops, but not in the field, it would undermine everything this rulemaking is trying to accomplish.”





