fabrication shops conducted by the National Stone Institute( NSI) and the International Surface Fabricators Association( ISFA) found that 43.5 % of shops had levels of respirable crystalline silica dust above this Action Limit. 9 Among 75 full shift personal air samples for respirable crystalline silica dust, 53 % were above the OSHA 8-hour PEL of 50 ug / m3. 10 Even when engineering controls are used( such as wet methods and ventilation), workers’ exposures to silica routinely exceed occupational exposure limits. 11 Many small fabrication shops are unable to afford the mechanical ventilation, wet methods and powered air purifying respirators that are necessary to protect fabrication workers and are required by section 5104. While there may be some shops that can reduce silica dust levels below the Cal / OSHA PEL, airborne concentrations of respirable crystalline silica in the majority of shops in California will likely continue to expose workers to unacceptable risks of a deadly disease.
6. Enforcement of existing regulations to control silica dust exposures is not likely to prevent more cases. The data presented by Cal / OSHA staff in August 2025 shows that the industry is routinely out of compliance with the revisions to § 5204 that require wet methods for cutting and grinding, frequent cleaning, providing and ensuring the use of appropriate respiratory protection, and conducting exposure monitoring for " high-exposure trigger " tasks. Cal / OSHA reported in August that the Division had opened inspections at 122 fabrication shops and had closed 99 of those inspections. Ninety-three of those 99 shops were found with violations of § 5204 or other Title 8 standards, representing 94 % of shops. At 24 % of shops( 24), the conditions required the compliance officer to issue an Order Prohibiting Use, immediately shutting down the shop, or in some cases a specific operation, based on an imminent silica hazard. 12
7. Australia has successfully prohibited the use, supply and manufacture of all engineered stone containing more than 1 % crystalline silica. 13 The Australian
9
McGowan CM, Cantley LF, Klein R, Redlich CA. Work Practices and Respirable Crystalline Silica Exposures in Stone Countertop Fabrication Shops. Am J Ind Med. 2025 Nov; 68( 11): 973-987.
10
Soo JC, Houlroyd J, Warren H, Philpot BJ, Castillo S. Respirable dust and respirable crystalline silica exposures among workers at stone countertop fabrication shops in Georgia from 2017 through 2023. Ann Work Expo Health. 2025 Jun 30; 69( 5): 473-485.
11
Soo JC, Houlroyd J, Warren H, Philpot BJ, Castillo S. Respirable dust and respirable crystalline silica exposures among workers at stone countertop fabrication shops in Georgia from 2017 through 2023. Ann Work Expo Health. 2025 Jun 30; 69( 5): 473-485.
12
Cal / OSHA Update to Occupational Safety and Health Standards Board – August 21, 2025.
13
The Australia domestic engineered stone prohibition commenced on July 1, 2024, with all jurisdictions except Victoria, Queensland and Australian Capital Territory implementing transition periods between July 1, 2024 and December 31, 2024. The prohibition applies to engineered stone benchtops, panels and slabs that contain at least 1 % crystalline silica as a weight / weight concentration; are created by combining natural stone materials with other chemical constituents( such as water, resins, or pigments); and becomes hardened. The prohibition does not apply to engineered stone products that are not benchtops, panels or slabs, such as finished products including jewelry, garden ornaments, sculptures and kitchen sinks. The prohibition also does not include concrete and cement products; bricks, pavers, and other similar blocks; ceramic wall and floor tiles; sintered stone( provided it does not contain resin); porcelain products( provided they do not contain resin); roof tiles; grout, mortar, and render, and plasterboard. Provided that the
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