The U.S. Department of Labor announced a proposal by its Mine Safety and Health Administration to amend current federal standards to better protect the nation’s miners from health hazards related to exposure to respirable crystalline silica, or silica dust. The proposed rule change will ensure miners have at least the same level of protections as workers in other industries.

Unhealthy levels of silica, a carcinogen, and exposures over time cause severe illnesses, including silicosis; progressive massive fibrosis; non-malignant respiratory disease, such as emphysema; kidney disease; and lung cancer. Exposure to mixed coal mine dust that contains respirable crystalline silica can lead to the development of coal workers’ pneumoconiosis, commonly known as black lung disease; multi-dust pneumoconiosis; and progressive massive fibrosis.

The proposed rule would require mine operators to maintain miners’ Permissible Exposure Limit to respirable crystalline silica at or below 50 micrograms per cubic meter of air for a full shift exposure, calculated as an 8-hour time weighted average. If a miner’s exposure exceeds the limit, the proposed rule would require operators to take immediate corrective actions to come into compliance.

“The purpose of this proposed rule is simple: prevent more miners from suffering from debilitating and deadly occupational illnesses by reducing their exposure to silica dust. Silica overexposures have a real-life impact on a miner’s health,” explained Assistant Secretary for Mine Safety and Health Chris Williamson. “Miners like a crusher operator at a California sand and gravel mine or a roof bolter in a West Virginia coal mine should never be forced to choose between preserving their health and providing for themselves and their families. This proposed rule furthers the Mine Act’s clear instruction to prioritize miners’ health.”

In addition to reducing the existing exposure limit, the proposal also includes other requirements to protect miners’ health — such as exposure sampling — and medical surveillance at no cost for metal and nonmetal miners. It would also replace existing outdated requirements for respiratory protection with a standard that reflects the latest advances in respiratory protection technologies and practices. 

Following the proposed rule’s publication in the Federal Register, MSHA will welcome public comments and announce dates for upcoming public hearings in Arlington, Virginia, and Denver, Colorado. The hearings will be open for in-person or online participation.