Crystalline Silica Rule Now in Federal Register

July 13, 2023 – The U.S. Department of Labor published a notice of proposed rulemaking by its Mine Safety and Health Administration (MSHA) to amend existing Federal standards to better protect the nation’s miners from health hazards related to occupational exposure of respirable crystalline silica, or silica dust.

The proposed rule change will ensure miners have at least the same level of protections as workers in other industries. MSHA previously announced and posted the text of the proposal on June 30, 2023.

The proposed rule would require mine operators to maintain miners’ permissible exposure limit to respirable crystalline silica at or below 50 micrograms per cubic meter of air for a full shift exposure, calculated as an eight-hour time weighted average. If a miner’s exposure exceeds the limit, the proposed rule would require operators to take immediate corrective actions to come into compliance.

In addition to reducing the existing exposure limit, the proposal also includes other requirements to protect miners’ health — such as exposure sampling — and medical surveillance at no cost for metal and nonmetal miners. It would also replace existing outdated requirements for respiratory protection with a standard that reflects the latest advances in respiratory protection technologies and practices.

MSHA welcomes public comments submitted online at the Federal rulemaking portal. Written comments and any information or materials must be received or postmarked by 12 a.m. EDT on Aug. 28, 2023.

The agency will hold three public hearings in Arlington, Va., on Aug. 3, in Beckley, W.Va., on Aug. 10 and in Denver, on Aug. 21. The hearings will be open for in-person or online participation.  

More information can be found at

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