Jul. 1—MORGANTOWN — The U.S. Mine Safety and Health Administration on Friday proposed a more stringent silica dust exposure rule to protect miners. The United Mine Workers of America and Sen. Joe Manchin are both celebrating.
An MSH fact sheet explains the need for the updated rule. It says respirable crystalline silica (silica dust) is an occupational carcinogen that puts workers at risk for developing preventable, severe diseases including: silicosis ; non-malignant respiratory diseases (e.g., emphysema and chronic bronchitis); lung cancer ; and kidney disease. Exposure to mixed coal mine dust containing silica dust can lead to the development of coal workers' pneumoconiosis (black lung), progressive massive fibrosis, and multi-dust pneumoconiosis.
"Each of these illnesses is chronic, irreversible, and potentially disabling or fatal, " MSHA says.
MSHA's current standard for metal /nonmetal (MNM) mines is 100 micrograms per cubic meter of air for a full-shift exposure—meaning an eight-hour time weighted average.
For coal mines, there is no separate standard for silica dust. Coal miners' exposures to respirable quartz are regulated through reductions in the overall respirable coal mine dust standard.
MSHA's proposed new standard would match the Occupational Safety and Health Administration standard adopted in 2016: for both MNM and coal mines, 50 micrograms per cubic meter for a full-shift exposure.
MSHA also proposes to establish an action level matching OSHA's: 25 micrograms per cubic meter across a full shift. When miners' exposure is above the proposed action level but below the permitted exposure limit of 50 micrograms, the proposed rule would require mine operators to conduct periodic sampling until miners' exposures are below the action level.
The proposed rule also includes medical surveillance requirements for MNM miners, modeled on existing medical surveillance requirements for coal miners. "Medical surveillance would provide maximum health protection for miners and provide MNM miners with information needed for early detection of respirable crystalline silica-related disease, reducing risk of substantial disability."
MSHA said after the proposed rule's publication in the Federal Register, it will welcome public comments and announce dates for upcoming public hearings in Arlington, Va., and Denver. The hearings will be open for in-person or online participation.
Assistant Secretary for Mine Safety and Health Chris Williamson said, "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."