On May 21, 2026, the California Occupational Safety and Health Standards Board (Board) met in Downtown Los Angeles to discuss and vote on a petition submitted by the Western Occupational and Environmental Medical (WOEMA) seeking expedited rulemaking to amend Title 8 California Code of Regulations Section 5204 - Occupational Exposures to Respirable Crystalline Silica. The proposed revisions would prohibit all fabrication and installation tasks involving engineered stone that contains more than 1% crystalline silica due to the significant health risks associated with worker exposure. 

The Board meeting drew widespread attention from occupational safety and health professionals, medical experts, worker advocates, public health officials, attorneys, industry representatives, and affected workers and their families. Public testimony throughout the meeting highlighted the growing urgency surrounding engineered stone-associated silicosis, the devasting impacts of this disease on workers and their families, and the need to protect workers in California. 

Supporters of the petition emphasized the need for immediate regulatory action without additional advisory committee study requirements, arguing that the severity of the disease and the increasing number of cases warrant expedited intervention. Several speakers noted that existing engineering controls and personal protective equipment have not been sufficient to adequately control worker exposure to respirable crystalline silica during fabrication and installation activities involving engineered stone. 

Industry representatives emphasized the importance of worker training, compliance with existing regulations, and the use of wet methods when working with engineered stone. Industry stakeholders expressed opposition to a blanket ban on engineered stone products, arguing that the material can be handled safely when appropriate exposure control measures are implemented. 

Among those providing testimony was Dr. Rachael Jones, Director of the Southern California Education and Research Center (SCERC), who urged the Board to take decisive action. 

"We've recognized this hazard for some time, but it's the accumulation of human misery that we've heard today and over the years, that brought us here today," Dr. Jones stated during public comment. "California should be a model for the nation and create momentum for the use of safer products and the protection of workers and the efficient use of our public health workforce to address problems that are emerging today. I urge the board to support the petition as submitted by WOEMA and enable Cal/OSHA to move forward with an expeditious emergency rulemaking to regulate this product more fully and prevent this disease." 

Following public comments, the Board voted to grant the WOEMA petition to the extent Cal/OSHA drafts emergency rulemaking to amend Title 8 California Code of Regulations Section 5204 - Occupational Exposures to Respirable Crystalline Silica. The Board simultaneously requested Cal/OSHA to convene advisory committees to undertake a review of Section 5204 and help answer whether engineered stone can be safely fabricated.  

What does this decision mean?

Following this vote, Cal/OSHA will convene advisory and scientific committees to review and evaluate several key issues. These committees will include diverse stakeholders to explore the applicability of proposed regulations to workers in the construction industry, the viability of an emergency temporary standard, and whether other high-silica-content natural stone products, such as quartzite, should be included in any future regulatory action. 

In addition, the committees will discuss how zero-silica alternative products could be incorporated into future regulations and evaluate the technical and scientific feasibility of safely working with engineered stone materials.

Background on Engineered Stone and Silicosis in California

Engineered stone, also known as artificial stone, is commonly used for kitchen, bathroom, and other countertops and is characterized by its high crystalline silica content, which can exceed 90%. Workers who fabricate engineered stone slabs into countertops have been found to experience exposures to respirable crystalline silica in excess of occupational exposure limits and to develop silicosis at relatively young ages after comparatively short durations of exposure.  

In California, across the United States, and internationally, a growing epidemic of silicosis - an occupational lung disease - is being observed as a result of exposure to respirable crystalline silica from engineered stone. 

According to the California Department of Public Health (CDPH), as of May 21, 2026, 562 confirmed cases of silicosis attributed to engineered stone have been identified in California (see figure below). Of these cases, 288 have been identified in Los Angeles County and 120 in Orange County. These cases are anticipated to represent only a fraction of the true number of affected workers due to underdiagnosis and barriers to healthcare access among vulnerable worker populations.