California doctors urge ban on engineered stone as silicosis cases surge

A former stoneworker named Lopez sat confined to his East Bay home, breathing with the help of a whirring oxygen supply machine through clear tubes pronged to his nostrils. After years of making kitchen countertops from engineered stone, the 43-year-old was diagnosed with silicosis, an often deadly lung disease linked to inhaling toxic dust the material releases when powercut.

The once-active father of four now awaits a double lung transplant. He can no longer support his family or walk a few steps without pausing to catch his breath. Two stonecutter friends died after working with the man-made material, also known as artificial stone or quartz. Three others are on a waitlist for lung transplants, he said.

“I feel desperate just sitting here unable to do anything,” said Lopez, an undocumented immigrant who worked in California for more than two decades. KQED is withholding his full name, as he fears losing vital medical care if arrested by federal authorities.

“It’s agonizing waiting for the hospital to call me so I can finally get the transplant I’m waiting for and be able to go back to work,” he said.

As silicosis cases surge in California’s countertop fabrication industry, medical and occupational safety experts warn that current regulations won’t protect hundreds more relatively young workers like Lopez from contracting the incurable illness. The state must act urgently to phase out hazardous engineered stone from fabrication shops, as Australia did, they say, to stem a growing health crisis.

Australia banned the use, supply and manufacture of engineered stone benchtops in July 2024, forcing major manufacturers to switch to silica-free alternatives in that market, though they still sell their higher-silica products in the U.S. The companies maintain that their products are safe if fabrication shops follow protocols.

A photo of a pair lungs with silicosis used in a Cal/OSHA presentation slide about the disease, and rising number of cases in California, at a public meeting on Nov. 13, 2025.

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“Silicosis is preventable when proper safety and health measures are in place to protect workers against inhalation of silica dust in the workplace,” a spokesperson for Cosentino North America said in a statement. “The company continues its efforts in research and development for the ongoing improvement of its products.”

Between 1,000 to 1,500 stoneworkers in California could develop silicosis within the next decade, leading to roughly 285 deaths, according to California’s Division of Occupational Safety and Health, or Cal/OSHA. The state is home to about 5,000 countertop fabrication workers, predominantly Latino immigrants.

Artificial stone in the U.S. market often contains more than 90% pulverized crystalline silica, far more than natural stones such as marble and granite. When workers powercut, polish and grind slabs of the material, tiny silica particles are released. If inhaled, they can lodge in the lungs and cause tissue scarring that progressively impedes breathing. Respirable silica can also lead to lung cancer, chronic obstructive pulmonary disease and other illnesses.

To save lives, the Governor’s Office could issue an emergency declaration pausing the processing of artificial stone until a permanent ban is pursued through rulemaking, according to a Sept. 4 memorandum obtained by KQED. Drafted by a committee of doctors, occupational safety experts and worker advocates convened by Cal/OSHA, the letter was addressed to the state board responsible for adopting new workplace safety regulations, but was not sent.

Gov. Gavin Newsom’s press office did not respond to requests for comment about his position on banning engineered stone in fabrication shops. A spokesperson with the Department of Industrial Relations, which oversees press requests for both Cal/OSHA and the Occupational Safety and Health Standards Board, said the draft had not been vetted.

“The memo referenced … is an incomplete working draft by the Silica Technical Committee and not by Cal/OSHA. None of the recommendations are final,” the spokesperson said in a statement. “Cal/OSHA continually works to protect the health and safety of California’s workers and enforces all regulations adopted by the Board.”

Several board members have publicly expressed dismay for months at the steep climb in silicosis cases, but the agenda for their next meeting on Thursday does not include decision-making on artificial stone.

Maegan Ortiz, director of the Instituto de Educacion Popular del Sur de California, said that although the state approved stricter standards nearly two years ago, California has made little progress in protecting stoneworkers still inhaling engineered stone dust on the job.

Lopez adjusts the breathing tube connected to his oxygen tank in his home in Pittsburg on Nov. 15, 2025. (Martin do Nascimento/KQED)

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“We need to ban this. I think the concern is great, but it is kind of like thoughts and prayers in the face of other crises that don’t go far enough,” said Ortiz, whose organization has been surveying stoneworkers in Los Angeles County, the state’s silicosis epicenter. “We’ve seen the conditions ourselves on the ground in terms of the amount of dust that is there, even in these bigger shops that are following the regulations. Workers see the dust, they carry it on them.”

Since 2019, more than 430 workers have been confirmed with silicosis in California, including 25 who died and 48 who underwent a lung transplant, according to state public health officials tracking reported cases. Half of those sick are located in Los Angeles County. Nearly all are Latino men, some in their 20s, who said they didn’t know how dangerous artificial stone dust could be. About 40% of silicosis cases were identified this year.

Lopez said he worked in licensed shops using safety gear and methods his supervisors said would protect him. He wore filter masks and cut and polished engineered stone with machines that covered slabs with water to suppress dust. But mounting evidence shows silica particles in artificial stone dust are so small and toxic that it doesn’t take much to hurt workers. Silica can penetrate filter masks and remain on workers’ clothes and tools when water dries.

Australia tried banning drycutting of engineered stone, similar to Cal/OSHA rules in place since December 2023 and a bill Newsom signed last month, SB 20. Australia also tried additional safeguards, including full-face powered air-purifying respirators, ventilation systems and monitoring, like California’s strict regulations that go beyond federal requirements. But in both places, experts say, the sophisticated and costly measures are not realistic for an industry made up of mostly small shops with only a few workers.

“I think it’s completely unfeasible,” said Dr. Ryan Hoy, a respiratory physician and researcher at Monash University in Melbourne, Australia. “I often use the analogy that you can work with asbestos safely, you can work with uranium safely, but you need to have in place very sophisticated control measures.”

In California, most fabrication shops are not complying with drycutting bans, respiratory protection, monitoring or other requirements. About 94% of 107 worksites investigated by Cal/OSHA had violations of the silica regulations as of Oct. 16.

Lopez’s wife said she wished her husband had more accurate information from manufacturers, vendors and employers before working with artificial stone so he could have chosen whether to take on the risk. Considering the impact of his disease on her family, the 41-year-old choked back tears.

“It’s painful because I’ve always seen him working. He’s always looked out for us. He’s the pillar of our family,” she said in Spanish, adding that her youngest son is 3. “It hurts us deeply.”

Lopez’s state disability benefits have run out, he said, and the family relies on financial support from their oldest daughter, a 20-year-old medical assistant. He became one of hundreds of workers in the U.S. and other countries who have sued top manufacturers of engineered stone — including Minnesota-based Cambria, Israel-based Caesarstone and Cosentino, headquartered in Spain — claiming silica-related injuries.

Caesarstone, which generated nearly half of its $303 million in revenue so far this year in the U.S. market, reported claims by more than 500 individuals in its latest financial results. The company recorded a $46 million provision for probable losses, with $24.3 million covered by insurance. But costs could grow, as most of the 320 U.S. claims are awaiting trial.

Caesarstone won one case in the U.S., which remains under appeal, and settled another this year, according to Nahum Trust, Caesarstone’s chief financial officer, during an earnings call this month. Last year, a jury awarded a 34-year-old stoneworker $52 million after finding Caesarstone and other companies liable, a decision the company has appealed.

The company developed crystalline silica-free countertop surfaces in preparation for restrictions in Australia and recently unveiled what it advertises as safer alternatives for fabrication workers in the U.S. Caesarstone’s sales were down this quarter in the U.S. and Canada, due to softness in the market and competitive pressures, according to Trust, but sales are up in Australia.

A stone fabricator places his hand on a table that he cut at his home in San Francisco on Oct. 17, 2023.

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“Our first year of real growth in this market since the silica ban implementation,” Trust said. “This reflects early recovery and the successful launch of our zero silica collection.”

Cosentino said it has also moved to offer newer products due to safety concerns, including a new mineral-surface product with zero crystalline silica that will be available next year globally.

Cosentino, Caesarstone and associations representing manufacturers declined to comment on why they continue selling their high-silica engineered stone products in the U.S. if they have alternatives for the Australian market.

Global demand for artificial stone, a multibillion-dollar industry in the U.S., is expected to significantly grow. In California, sales are expected to increase even more due to efforts to rebuild the more than 16,000 homes and buildings destroyed by January wildfires in Los Angeles.

Consumers prefer the stain-resistant material because it’s often cheaper than natural stone and offers diverse colors and designs. But many homeowners don’t know of the potential health impacts to the workers who make their countertops.

Pulmonologists predict silicosis cases will keep rising, even if exposure to silica dust stopped immediately. By the time workers feel symptoms, the disease has often advanced, Hoy said.

“Unfortunately, that is definitely the tip of the iceberg of workers that are currently affected,” said Hoy, who screened stoneworkers in Australia for silicosis and treats diagnosed patients.

As manufacturers switched to silica-free products in Australia, costs increased, but consumers still purchased countertops for renovations and new buildings. The industry carried on without the old material.

Dr. Hayley Barnes, a pulmonologist who studied silicosis in Australia, said that initially, talking about banning the material in that country felt like a huge ordeal, with predictions that the building industry would collapse and jobs would disappear. But that didn’t happen, she said.

“The companies just made a low-silica or no-silica product, which is currently available in Australia and many other countries,” Barnes said.

Now medical director of UCSF’s Interstitial Lung Disease Program, she worries many cases in California have not yet been diagnosed, and stoneworkers are suffering.

“We could do better. It’s been done elsewhere,” Barnes said. “People would still get their houses and apartments built and workers would be better protected.”

Dr. Sheiphali Gandhi, an assistant professor of medicine at UCSF and a colleague of Barnes who treats dozens of silicosis patients, said she wants California to begin phasing out artificial stone countertops. The move would ensure consumers purchase materials that also protect workers, she said.

“We’ve tried all these regulations, but we still are seeing that the cases are going up,” Gandhi said. “We need to move towards the more effective strategies of elimination or substitution, where we really go for safer alternatives.”

For now, Gandhi must wade through a stack of about 40 additional cases of very sick workers she has been referred.

“It’s just like every month, my mailbox is full of more referrals of silicosis cases,” she said. “The number of cases is exploding. It’s insane.”