Key takeaway
What This Development Means
Cal/OSHA has proposed prohibiting workplace manufacture and fabrication of artificial stone containing more than 1.0% crystalline silica by weight. The discussion draft includes conditional transition periods and material-composition records. It is not an adopted ban. Fabricators and suppliers should assess affected materials while continuing to meet existing workplace requirements.
Has California already adopted this engineered-stone ban?
The inspected official material is a discussion draft, not evidence of an adopted ban. It supplies no final effective date.
Would all existing stone stock receive a six-month exemption?
No. The draft's exception is limited to qualifying material purchased, contracted for or held before the eventual effective date. It also requires full compliance with section 5204 and ends 180 days after that date.
Source basis: Cal/OSHA engineered-stone rulemaking
Cal/OSHA Proposes A Material-Based Restriction
California's workplace safety regulator has proposed prohibiting the manufacture and fabrication of artificial stone containing more than 1.0% crystalline silica by weight. The measure would affect countertops and similar products, giving fabricators and suppliers a reason to review material specifications and outstanding orders.
Cal/OSHA's 16 September discussion draft is part of an emergency rulemaking process. It is not an adopted prohibition. The official advisory page gives 30 September 2026 as the deadline for comments on that draft. That deadline has passed.
Scope And Transition Depend On The Final Text
The proposed section 5204.1 covers workplace manufacture or fabrication of countertops, backsplashes, walls, flooring, waterfall edges and similar products made from slabs or panels. Fabrication includes cutting, grinding, drilling, polishing and other processing into a final or near-final product.
The draft excludes fired ceramic and porcelain tiles and panels from its definition of artificial stone. Its construction provisions also distinguish on-site fabrication from installation, maintenance and repair. Installation is defined to include only minor on-site adjustments to previously fabricated slabs. Businesses should therefore examine the actual work performed when assessing the proposed exception.
The prohibition would begin 60 days after the emergency regulation's effective date. A limited exception would allow qualifying material purchased, contracted for or held before that effective date to be processed for up to 180 days. Employers relying on the exception would have to comply fully with section 5204. The draft leaves the effective date blank, so neither period can yet be converted into a calendar deadline.
Composition Evidence Would Determine Material Treatment
Employers would need records demonstrating that material contains no more than 1.0% crystalline silica by weight or falls outside the artificial-stone definition. Without those records, the draft would require treatment as artificial stone above the threshold.
Foresight analysis. Procurement evidence could become as important as workshop controls in deciding which materials can be processed. A supplier's broad description of a slab as lower-silica would not, by itself, establish that it meets the proposed numerical threshold.
Fabricators should match composition evidence to material batches and separate existing stock from future orders. Suppliers should identify which technical records support their specifications. Both should track the final scope and commencement notice before applying a transition period to a contract.
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