WASHINGTON – The U.S. Department of Labor’s Mine Safety and Health Administration today unveiled a proposed rule to better protect the nation’s miners from health hazards associated with exposure to crystalline silica, also known as silica dust or quartz dust.The proposed rule amends the 2024 Biden-era final rule by adding practical, commonsense, risk-based improvements to compliance requirements, exposure monitoring, medical surveillance, recordkeeping, and respiratory protection based on OSHA standards. The proposal retains the permissible exposure limit for respirable crystalline silica at or below 50 micrograms per cubic meter of air and action level at 25 micrograms.Several developments after publication of the 2024 respirable crystalline silica