MSHA temporarily pauses enforcement of silica final rule

Washington — The enforcement date for the Mine Safety and Health Administration’s final rule on miner exposure to respirable crystalline silica has been pushed to Aug. 18.

Citing “unforeseen NIOSH restructuring” and “other technical reasons,” the agency announced a temporary enforcement pause on April 8. Coal mine operators initially had been given a compliance date of April 14 for the rule, which had gone into effect in June.

The long-anticipated rule lowers the permissible exposure limit for respirable crystalline silica to 50 micrograms per cubic meter of air – half the current limit – over an 8-hour time-weighted average. The rule also increases silica sampling and enforcement at metal and nonmetal mines, as well as requires mine operators to provide periodic health exams at no cost to miners.

Crystalline silica can damage lung tissue and lead to black lung disease, chronic obstructive pulmonary disease or silicosis.

MSHA says that the pause will “provide time for operators to secure necessary equipment and otherwise come into compliance” and “help accredited laboratories gain proficiency in MSHA analytical methods.”

On March 27, the Department of Health and Human Services announced a restructuring plan that will merge NIOSH with four other agencies. That restructuring is expected to include layoffs of more than 870 NIOSH employees.

MSHA says these developments “may impact the Pittsburgh Mining Research Division, the National Personal Protective Technology Laboratory, and the supply of approved and certified respirators and personal dust monitors.”

The announcement comes on the heels of the 8th U.S. Circuit Court of Appeals on April 4 granting a temporary stay of the rule. On April 2, the National Stone, Sand & Gravel Association filed a petition seeking an expedited emergency stay.

NSSGA claims in the petition that “MSHA lacks evidence that operators can feasibly comply” with the new PEL and “mandates extensive, expensive medical monitoring far beyond what MSHA has authority to compel.” The petition adds that the rule is “deeply arbitrary” while its “harm to mining operators is severe, irreparable and imminent.”

The appeals court will rule whether to permit enforcement of the silica rule or halt it permanently.

The rulemaking first appeared on the Department of Labor’s regulatory agenda in 1998. OSHA estimates that about 2.3 million workers are exposed to silica dust each year.

In an April 9 post to LinkedIn, former MSHA head Joe Main writes that “shutting down enforcement of the silica rule” is “just one more Trump administration action to cut miners health and safety.”

The compliance date for metal and nonmetal operators remains April 8, 2026, MSHA says.