Supplemental Public Comment Regarding Cal/OSHA’s October 22, 2026 Discussion Draft

Re: Supplemental Public Comment Regarding October 22, 2026 Discussion Draft

Proposed Sections 5204.1, 5204, and 1532.3

Submitted to the California Division of Occupational Safety and Health (Cal/OSHA) on October 24, 2026.

Dear Research and Standards Branch:

I submitted comments on September 19, 2026, regarding the proposed emergency regulation addressing artificial stone and respirable crystalline silica. I appreciate the substantial changes reflected in the October 22 discussion draft. In particular, the revised proposal strengthens product verification by requiring an SDS and X-ray diffraction analysis for each SKU and by treating material lacking adequate documentation as artificial stone containing 1.0% or more crystalline silica. The proposed prohibition on installing such material after the transition period also represents an important prospective prevention measure.

I would like to raise one remaining implementation issue: whether information identifying artificial stone and its crystalline silica content will reliably remain available to the worker who ultimately encounters and disturbs the material.

This issue is relevant to both current residential construction and future work on previously installed artificial stone. CDPH has described California’s countertop industry as fragmented and dominated by small-scale operations, with more than 1,300 fabrication operations and a median of five workers per operation. CDPH has also recognized the potential for fabrication activity to shift to on-site locations. The occupational health literature further shows that artificial-stone exposure can occur during installation work in residential settings.

The October 22 draft establishes a robust system for determining product composition using SKU-specific SDS and X-ray diffraction documentation. However, I do not see a provision that ensures this information remains linked to the material as it moves downstream from the supplier to the fabricator, installer, contractor, or subcontractor, or after the material becomes part of a building.

This distinction is important because the worker performing the dust-generating task may not be the same as the worker or employer who originally purchased the material. The separation can widen over time. Property owners, contractors, subcontractors, and workers may change, while the original SDS, laboratory analysis, SKU, manufacturer, and supplier may no longer be known.

The October 22 draft expressly permits on-site maintenance and repair of artificial stone, while existing silica standards provide important protections when silica-generating work is identified. The remaining issue is therefore one of hazard recognition and continuity of information: how will an employer or worker know that material encountered at a temporary or residential worksite is artificial stone, or that its composition should be determined before cutting, drilling, grinding, resurfacing, removing, or otherwise disturbing it?

The magnitude of future disease attributable specifically to the repair, remodeling, or removal of previously installed artificial stone remains unestablished. Nevertheless, the persistence of this material in the built environment, combined with the fragmented and decentralized nature of parts of the construction workforce, creates a foreseeable risk of disease.

I encourage Cal/OSHA to consider whether a durable mechanism is needed to ensure that material identification and hazard information remain accessible to downstream employers and workers, including those at temporary and residential worksites and those who may encounter artificial stone years after its original installation. I do not presume to recommend the appropriate technical or regulatory mechanism. That question would benefit from expertise in industrial hygiene, construction practices, enforcement, and regulatory implementation.

I recently discussed the longer-term component of this issue in a Beacon Hill Medical Consulting article, “Hidden in Plain Sight: The Legacy Hazard of Artificial Stone in the Built Environment” (October 15, 2026), available at https://beaconhillmedicalconsulting.com/blog/hidden–in–plain–sight–the–legacy–hazard–ofartificial–stone–in–the–built–environment. I offer it as supplementary discussion of the lifecycle issue rather than as scientific evidence supporting the proposed regulation.

Thank you for the opportunity to submit this supplemental comment and for Cal/OSHA’s continued efforts to prevent occupational silicosis.