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MSHA enforcement effort focused on protecting workers from silica

Photo: small smiles/iStockphoto

Arlington, VA — As the Mine Safety and Health Administration works to develop a standard on worker exposure to respirable crystalline silica, the agency has launched an enforcement initiative aimed at boosting protections against the hazardous material.

Workers can inhale silica dust during mining and other operations, including cutting, sawing, drilling or crushing materials such as rock and stone. Crystalline silica can damage lung tissue and lead to lung disease, coal workers’ pneumoconiosis, chronic obstructive pulmonary disease or incurable silicosis. OSHA estimates that 2.3 million workers are exposed to silica dust annually.

Under the initiative, announced June 8, MSHA will conduct spot inspections at coal and metal and nonmetal mines “with a history of repeated silica overexposures,” while expanding silica sampling at mines and offering compliance assistance to mine operators.

Other aspects of the initiative:

  • Increased oversight and enforcement of known silica hazards at mines with previous citations for exposing miners to silica dust levels over the existing permissible exposure limit of 100 micrograms per cubic meter of air. For metal and nonmetal mines in which the operator hasn’t abated hazards in a timely fashion, MSHA will issue a 104(b) withdrawal order until the overexposure hazard has been abated. For coal mines, the agency will encourage changes to dust control and ventilation plans to address known health hazards.
  • Reminding miners of their rights to report hazardous health conditions, including attempts to interfere with the sampling process.

“Simply put, protecting miners from unhealthy levels of silica cannot wait,” MSHA administrator Chris Williamson said in a press release. “We are committed to using every tool in MSHA’s toolbox to protect miners from developing debilitating and deadly lung diseases that are entirely preventable. We have seen too many miners carrying oxygen tanks and struggling to breathe just to take a few steps or do the simplest of tasks after having their lungs destroyed by toxic levels of respirable dust.”


A proposed rule on respirable crystalline silica is included in the Department of Labor’s regulatory agenda for fall 2021, issued Dec. 10. The agenda stated MSHA’s intent to publish a notice of proposed rulemaking in May.

“Our agency is working hard and is committed to issuing a silica rule that will enhance health protections for all miners,” Williamson said. “The enforcement initiative that we are announcing today is a step we can take now while we continue the rulemaking process toward the development of an improved mandatory health standard.”

MSHA’s silica exposure limit of 100 micrograms per cubic meter of air was established in 1969. Although OSHA has since lowered its silica exposure limit to 50 micrograms per cubic meter, a November 2020 report from the DOL Office of Inspector General states “both OSHA and NIOSH warned that 50 μg/m³ is the lowest feasible limit, not the safest.” The report contends MSHA’s silica exposure limit is out of date, which “illustrates the need for current action.”

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