Washington — The Mine Safety and Health Administration has delayed “indefinitely” the deadline for metal and nonmetal mine operators to comply with its final rule on miner exposure to respirable crystalline silica.
Citing ongoing litigation challenging the rule, the agency on April 6 announced the latest postponement, which affects workers who mine metal, nonmetal, stone, sand and gravel.
The rule went into effect in June 2024. It lowers the permissible exposure limit for respirable crystalline silica to 50 micrograms per cubic meter of air – half the previous limit – over an 8-hour time weighted average. The new PEL matches the one OSHA established in 2016.
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.
The National Stone, Sand & Gravel Association, which filed the lawsuit, claims the rule is “deeply arbitrary.”
In April 2025, the 8th U.S. Circuit Court of Appeals granted a temporary stay of the final rule in response to NSSGA’s petition. Coal mine operators, who are also affected by the silica rule, had been given an initial compliance date of April 14, 2025.
In a Nov. 26 status update on the lawsuit, a group of attorneys representing MSHA wrote that the agency will “engage in limited rulemaking to reconsider” portions of the final rule. On March 9, MSHA issued a notice stating it will “continue to temporarily pause enforcement of the requirements in the silica rule for mine operators until the litigation is concluded.”
Multiple studies show that cases of coal workers’ pneumoconiosis, or black lung – a deadly condition caused by exposure to respirable coal mine dust – are on the rise.
Rebecca Shelton, director of policy for the Appalachian Citizens’ Law Center, an advocacy group, said that “if the Trump administration actually cared about protecting coal miners from black lung, we’d have a strong silica rule in place right now.”
Shelton added: “Our message to Trump’s MSHA is simple: It is on you to stop the delays. Put a strong rule in place and fight to enforce it before any other miners get black lung.”
