US Department of Labor unveils updated proposed rule designed to protect miners’ health from silica dust exposures

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 final rule led to MSHA's decision to develop a new proposed rule related to silica dust, including the U.S. Court of Appeals for the 8th Circuit's stay of the compliance deadlines in the final rule. MSHA announced in an April 2026 program information bulletin that it would delay enforcement of the requirements in the 2024 final rule because of the stay, while continuing to enforce existing standards.

After publication of the proposed rule in the Federal Register, MSHA will welcome public comments and announce the date for an upcoming public hearing. The hearing will be open for online participation.

Comments are due 60 days after the rule's publication in the Federal Register.

Read the proposed rule on respirable crystalline silica exposure.