Respirable Crystalline Silica
MSHA published a final rule in 2024 to set the permissible exposure limit (PEL) for respirable crystalline silica at 50 micrograms per cubic meter of air. EMA agrees that this change is long overdue and would harmonize the limit with the Occupational Safety and Health Administration. As noted by OSHA’s Inspector General in 2016, “OSHA indicated that after evaluating the best available evidence it was uncertain if there was any limit that would result in zero harm to workers,” but that “both OSHA and NIOSH warned that 50 μg/m³ is the lowest feasible limit.”
However, EMA’s comments to MSHA questioned the necessity of applying an Action Limit of 25 μg/m³ equally in both the coal and metal/nonmetal sectors of the mining industry. There is documented evidence the metal/nonmetal sector is not similarly afflicted with silicosis and pneumoconiosis, and numerous witnesses at MSHA’s silica hearings contended that the risk has proven to be manageable in that sector.