The California Occupational Safety and Health Standards Board meets May 16 to consider readopting the state’s emergency temporary standard (ETS) for occupational exposures to respirable crystalline silica.

The board adopted an ETS on December 14, 2023, which became effective December 29, to protect workers in the stone fabrication industry from silicosis. California’s permanent silica standard was promulgated based on instances of silicosis in traditional industries such as mining, quarrying, and sandblasting, according to the board. The board characterized the permanent standard as not well calibrated to the small businesses and working conditions of the stone fabrication industry.

The board has proposed readopting the silica ETS, with some changes, for a 90-day period, as cases of and deaths from silicosis continue among workers in the artificial stone fabrication industry. Under California administrative law, emergency standards remain in effect for 180 days. The board may readopt temporary standards twice for an additional 90-day period each.

The Occupational Health Branch (OHB) of the California Department of Public Health (CDPH) reported to the Division of Occupational Safety and Health (Cal/OSHA) that the number of confirmed cases of silicosis among workers in the industry had increased from 91 in October 2023 to 127 by April 2024—a 40% increase over a period of 6 months. The OHB also reported three additional deaths from silicosis, for a total of 13, as well as a total of 16 lung transplants to date.

Before the board’s initial adoption of the ETS, OHB investigators reported 52 California workers with silicosis who were exposed to respirable crystalline silica while fabricating countertops from artificial stone.

The median age of those workers was 45 years at diagnosis; 51 (98%) were Latino men. Ten (19%) died by the time investigators reported their findings. The median age at the time of death was 46 years, with a median work tenure of 15 years.

Requirements of the ETS adopted in December include work practices such as:

• Using wet methods,
• Properly handling all waste materials,
• Employing safe cleanup housekeeping methods, and
• Monitoring the air to confirm respirable crystalline silica levels are below the emergency rule’s action level.

The existing emergency rule also contains respiratory protection requirements that include the use of a full-face, tight-fitting, powered air-purifying respirator (PAPR), or an equally protective alternative, and an organic vapor cartridge for artificial stonework, with certain exceptions. The ETS also requires the use of a supplied-air respirator under certain conditions.

The board has proposed removing the requirement to provide respirators with organic vapor cartridges for high-exposure trigger tasks. Cal/OSHA determined that exposure to organic vapors during high-exposure trigger tasks is unlikely to reach or exceed the relevant permissible exposure limits.
Cal/OSHA concluded there isn’t sufficient justification to require that respirators be equipped with organic vapor cartridges when workers perform such tasks.

The board also has flagged several industries that haven’t been identified as contributing to the current silicosis epidemic in California. The proposal for readopting the emergency rule would add exemptions from the requirements for high-exposure trigger tasks for industries that include outdoor quarries and outdoor open-pit mines and the fabrication of tombstones, monuments, memorials, and burial vaults.