Cal/OSHA Proposes Ban on Fabrication, Manufacture of Certain Artificial Stone Products

Proposed changes to California’s silica standard that would prohibit the manufacture and fabrication of artificial stone containing more than 1 percent crystalline silica are described in a discussion draft published on Sept. 16 by Cal/OSHA, the state’s Division of Occupational Safety and Health. This emergency rulemaking is a response to the increasing number of silicosis cases among fabricators and installers of artificial stone countertops, which may contain more than 90 percent silica, according to an alert (PDF) from OSHA and NIOSH. The discussion draft includes proposed language for a new section in Cal/OSHA’s standard on occupational exposures to respirable crystalline silica that outlines “crystalline silica activities strictly prohibited” as well as changes to two other sections, including one on silica exposures in construction work.

The new proposed section would prohibit the manufacture or fabrication of artificial stone containing more than 1 percent crystalline silica by weight beginning 60 days after the effective date of the emergency regulation. A limited exception would allow employers to manufacture or fabricate artificial stone already in their possession or product that was previously purchased or contracted for within 180 days—approximately six months—of the regulation taking effect. The new section would also require employers to notify workers both verbally and in writing “that the manufacture or fabrication of artificial stone containing crystalline silica is dangerous to life and health, and that its manufacture or fabrication is prohibited in any workplace.” New recordkeeping requirements call for employers to maintain records of these employee notifications as well as documentation demonstrating that their materials contain less than 1 percent crystalline silica or are not artificial stone.

Proposed changes to one existing section of California’s silica standard include a new definition for an “artificial stone action level” of 3 μg/m3 of airborne respirable crystalline silica calculated as an eight-hour, time-weighted average and a revised definition for “wet methods” that clarifies that the use of water sources that are not continuous—water bottles, for example—are not acceptable. Changes to another section that applies to silica exposures in construction would clarify that the new section also applies to on-site fabrication of artificial stone containing more than 1 percent silica but not to on-site installation, maintenance, or repair of artificial stone products.

“‘Installation’ means fitting, positioning, leveling, securing, and final on-site modification or assembly of artificial stone slabs that were previously fabricated,” the proposed changes read. “This is limited to minor on-site adjustments to improve fit.”

Since 2019, more than 650 confirmed cases of silicosis have been identified among workers in California’s artificial stone fabrication and installation industry, according to the Occupational Health Branch of the California Department of Public Health. A dashboard maintained by the department and last updated on Sept. 17 indicates that 170 cases have been confirmed in the state this year, now nearly double the number of cases that were confirmed as of late May.

Comments on the discussion draft may be submitted via email to the Cal/OSHA Research and Standards Unit until Sept. 30. For further details, visit the emergency silica rulemaking page on the website of the California Department of Industrial Relations.