California's workplace-safety agency, Cal/OSHA, posted a revised draft of its proposed regulations for fabricating materials containing crystalline silica on Oct. 22, 2026. The agency established a short public comment window, with feedback due on Oct. 30, 2026. The updated proposal adds new documentation requirements for fabrication shops and refines the definitions in the Cal/OSHA artificial stone rule.
The revised text modifies the definition of artificial stone by changing references to a 1% crystalline-silica threshold to "less than 1%" in several places. It also explicitly clarifies materials excluded from the artificial stone classification, while requiring fabricators to maintain safety data sheets and specialized laboratory analysis for every product stock-keeping unit (SKU) stored in their facilities.
Concurrently, federal lawmakers introduced H.R. 10798, the Silicosis Prevention and Treatment Act, in the U.S. House of Representatives on Oct. 13, 2026. The federal bill proposes $10 million in annual grant funding for healthcare screening, education, and pulmonary rehabilitation for heavily affected industries, though it does not establish manufacturing or fabrication restrictions.
Definition Changes and Material Exclusions
In the revised draft, Cal/OSHA adjusted the scope of regulated composite surfaces. References to a 1% crystalline-silica threshold for "artificial stone" were changed in several places to "less than 1%".
The revised draft spells out what is excluded from the artificial stone definition: uncrushed or milled natural stone; ceramic and porcelain products; terrazzo; and sintered stone, concrete, or cement slabs containing no binders. For suppliers of natural stone, porcelain and binder-free sintered surfaces, the list makes the boundary of the rule more explicit.
SKU-Level XRD Lab Testing and SDS Mandates
The largest change in the revised draft is in recordkeeping for fabrication businesses. Under the proposed provisions, fabrication businesses would need, for any product, a Safety Data Sheet (SDS) for every SKU in stock.
Furthermore, the revised draft mandates "a laboratory analysis for each SKU using X-ray Diffraction from a laboratory" accredited in accordance with state code. The draft stipulates that that analysis would need to be "provided by the importer, manufacturer, distributor, supplier, or other source." In practice, the draft would push test documentation upstream to the companies that supply slabs to California shops. For the earlier stages of this rulemaking, see Cal/OSHA's first draft of the engineered stone rule and the NSI and ISFA comments on that draft, including a fabricator-licensing proposal.
Public Comments and Standards Board Review
The first draft, whose comment period in September was extended by one extra week, drew 45 written comments. Feedback was submitted by California health agencies and advocacy groups, six fabrication shops, three union representatives, two legal firms involved in silicosis-victim cases, and two surface manufacturers (LX Hausys and Caesarstone). Major industry associations also submitted formal feedback, including the International Surface Fabricators Association, the Natural Stone Institute, and the Tile Council of North America. For background on how low-silica and sintered products are treated in silica rules, see low-silica stone and sintered stone regulations.
Next step: the proposal goes to the state Occupational Safety and Health Standards Board for a final determination. The next Standards Board meeting is scheduled for Nov. 19, 2026, in Monterey, Calif. As of the reporting date by Stone Update, no agenda had been published for that meeting.
Federal Silicosis Prevention and Treatment Act
At the federal level, Congress received H.R. 10798, the Silicosis Prevention and Treatment Act, on Oct. 13, 2026. Introduced by Rep. Lou Correa (D-Calif.) and Rep. Maxine Dexter (D-Ore.), the bill was referred to the House Committee on Energy and Commerce.
The bill would create a federal grant program for healthcare providers, funded at $10 million per year across federal fiscal years 2027–2031. Grant funds would support community outreach and education on silicosis; provide screening, diagnosis and treatment; develop education programs for patients, families and workers in heavily affected industries; and offer pulmonary rehabilitation and patient care coordination.
Rep. Correa's congressional district includes the Tile Mile in Anaheim, where workers cut and fabricate manufactured stone countertops. Orange County accounts for more than 135 of California's more than 660 confirmed silicosis cases. Correa said: "No worker should lose their ability to breathe because of the job they do to support their family." The federal bill funds healthcare education and treatment; it does not regulate materials or fabrication.
What It Means for Buyers
- Prepare for Upstream XRD Testing Demands: If adopted as drafted, the requirement for an SDS and an accredited X-ray Diffraction (XRD) lab report per SKU will lead California fabricators to demand certified test sheets directly from importers, distributors, and overseas suppliers.
- Document Products Falling Outside the Definition: Importers of natural stone, porcelain, ceramic, terrazzo, and binder-free sintered stone should be ready to document that their products fall within the exclusions listed in the draft.
- Maintain Systematic SKU-Level Records: Slab distributors and fabrication operations serving California should establish organized digital archives of safety data sheets and laboratory analyses cataloged specifically by SKU.
- Track the Standards Board Schedule: Because the rule remains in draft form, buyers should follow the Nov. 19, 2026 Standards Board meeting in Monterey and check whether the proposal is on the agenda.
- Distinguish Healthcare Grants from Operational Bans: Buyers should recognize that H.R. 10798 focuses on funding medical education and treatment programs rather than imposing commercial restrictions on stone fabrication.
