Quartz countertops have skyrocketed in popularity over the last decade, but new research suggests the material poses a deadly health risk to the workers who make it.

A study published Monday in the journal JAMA Internal Medicine identified 52 cases of an irreversible, potentially life-threatening lung disease among workers in California who fabricate quartz slabs. Ten of those workers died, and three received lung transplants.

Although quartz is a naturally occurring mineral, the version found in homes is an artificial mixture of silica — a chemical compound — and other materials including resins and dyes. Breathing in large amounts of silica dust can cause inflammation or scarring, also called fibrosis, in the lungs.

This can lead to silicosis, a disease that results in permanent lung damage and sometimes death due to respiratory failure. Patients may start off with a cough or shortness of breath, then eventually require oxygen therapy or a lung transplant.

"It’s an incurable disease. There’s no treatment for it. You can’t get the silica out of anybody’s lungs," said Arthur Frank, a professor of environmental and occupational health at Drexel University, who was not involved in the new research. "Once it’s there, it’s going to stay there — and the fibrosis can continue to occur, even if you don’t get any more exposure."

The new study estimated that 100,000 workers in the U.S. are potentially at risk of silicosis due to exposure to silica dust

Dr. Jane Fazio, a co-author of the study and a pulmonary specialist at Olive View-UCLA Medical Center, said sales of engineered quartz stone countertops have risen more than 600% in the U.S. in the last 10 years.

“It’s really marketed as more durable material and more versatile and less maintenance than the natural stone alternatives,” she said.

Whereas silica typically makes up less than 30% of natural stones like marble or granite, quartz contains around 90% or more, according to Jenny Houlroyd, an industrial hygienist at Georgia Tech, who was not involved in the new research.

To make quartz slabs, manufacturers first crush the quartz and compress it under high heat, then send it to shops where workers cut, sand and polish the material. Those workers can be exposed to nano-sized particles of silica dust, which get trapped in their lungs.

Houlroyd works with countertop companies in Georgia to assess their exposure levels by collecting air samples.

“With the introduction of engineered stone, or quartz countertops, we saw exposure levels increase astronomically,” she said, adding: “It’s not just the amount of silica dust that’s getting into their lungs, but it’s also the size of it that is causing harm as well.”

Rising silicosis cases in California

Silicosis is a centuries-old disease, but researchers first flagged cases among fabricators of quartz countertops more than a decade ago.

A 2012 study documented 25 cases in Israeli workers from 1997 to 2010 and warned that further cases were likely unless effective preventive measures were taken and safety practices were enforced.

In 2019, the Centers for Disease Control and Prevention reported 18 cases of silicosis among workers in the stone fabrication industry across four U.S. states.

The new study confirms a rise in silicosis among quartz fabricators in California. Just eight of the 52 cases it describes had been reported previously, according to an accompanying editorial.

The workers in the study who got sick were mostly younger men — around age 45 — who had been in the industry for about 15 years. The majority were diagnosed from 2019 to 2022.

One of Fazio's patients, 27-year-old Leobardo Segura-Meza, was hospitalized in June with a collapsed lung and is awaiting a transplant.

“Every day I hope that the phone rings telling me to come to the hospital to get my new lungs,” he said in a news release.

Some places are considering new regulations

Silicosis is not a nationally reportable illness, so most states don't screen for it. Fazio said the California Public Health Department started looking for cases after two workers died of severe silicosis in 2018, but the state doesn't have a mandated surveillance system.

In 2019 and 2020, the California Division of Occupational Safety and Health took air samples from 47 stone fabrication worksites and found that 51% of them and 25% of the employees had silica dust exposure levels above the maximum limit — 50 micrograms per cubic meter of air over an eight-hour workday.

As awareness of this hazard has grown, some places are starting to consider policy changes. Los Angeles County is considering a ban on the sale, fabrication and installation of quartz surfaces. And Australia is weighing a total ban on the use of engineered stone.

But the experts interviewed for this article worried that local bans might just push companies to set up shop in different places.

On a national level, the Occupational Safety and Health Administration already requires fabrication shops to use “dust controls” to limit workers’ exposure to silica dust, such as saws with built-in systems that apply water to the blade to prevent dust from flying into the air. If those measures can’t lower silica exposure to safe levels, shops must provide workers with respirator masks.

But workplace safety experts said those interventions aren’t enough.

“I personally have not seen a way that it can be safely done, and I think that we need to really be raising the alarms about how many workers are getting sick from this,” Houlroyd said.

OSHA also requires fabrication shops to measure workers’ exposure to silica if the levels are suspected of being high. Shops are required to offer medical exams to workers exposed to high levels of silica dust for 30 or more days per year. But Fazio said they rarely do so.

“Everyone who works in the industry should get a baseline X-ray and lung function test, and then thereafter every three years, but really, that’s not happening,” she said. “Employers aren’t paying for it. There’s nowhere to go to get those exams.”

Because of that, Fazio added, “I anticipate that a lot of folks are walking around that probably have silicosis and don’t know it yet.”

Houlroyd said few workers get employer-provided medical screenings because small businesses often can't afford them, workers may change jobs before they have a chance to get screened, and some people are reluctant to participate in medical tests, particularly if there is a language barrier.

Fazio suggested that if states were to impose a tax on quartz slabs, that money could go toward better employer screening, prevention and education.

Frank, meanwhile, said companies should be held responsible for cases of silicosis among their workforces.

“This is an absolutely horrible, preventable, work-abusive situation that never should have occurred,” he said.

For people who already have quartz countertops or tables in their homes, the experts said, there is no risk of inhaling silica dust except during the installation process — and even then, a one-time exposure is unlikely to pose a hazard.