On April 18, the U.S. Department of Labor’s Mine Safety and Health Administration issued the final rule on Lowering Miners’ Exposure to Respirable Crystalline Silica and Improving Respiratory Protection, which lowers the permissible exposure limit of respirable crystalline silica to 50 micrograms per cubic meter of air for a full-shift exposure, calculated as an eight-hour, time-weighted average. If a miner’s exposure exceeds the limit, mine operators are required to take immediate corrective actions to come into compliance.

The final rule will take effect on June 17, 2024. Coal mine operators have 12 months to come into compliance with the final rule’s requirements while metal and nonmetal mine operators have 24 months to come into compliance (including medical surveillance). Read MSHA’s fact sheet on the rule.

ABC, as a steering committee member of the Construction Industry Safety Coalition, submitted comments on the proposed rule, stating, “While the CISC supports MSHA’s efforts to protect mine workers from overexposure to crystalline silica, the coalition requests that MSHA exempt construction activities conducted on MSHA sites. Construction activities are currently covered under the Occupational Safety and Health Administration’s final rule addressing exposure to crystalline silica (‘silica standard’). Having to comply with two different sets of rules is confusing, duplicative and unnecessary, especially when compliance with the OSHA silica standard has proven effective for construction operations.” CISC urged MSHA to develop a Table 1, like the one found in the OSHA silica standard, so that the industry has clear-cut standards and options for complying with the MSHA rule.

CISC’s comments further stated, “Our internal review of such exposure data indicates that most if not all job tasks in those surface quarrying operations are incapable of exceeding the proposed PEL. We therefore request MSHA review such data and produce a report for review and comment.”

MSHA did not include CISC’s recommendations in the final rule, instead determining that a Table 1 approach does not adequately protect miners, due to the diverse range of activities involved in mining, and constantly changing mining conditions.

According to OSHA, in addition to reducing exposure limits, the final rule does the following:

• Requires mine operators to use engineering controls to prevent miners’ overexposures to silica dust and use dust samplings and environmental evaluations to monitor exposures. 
• Compels metal and nonmetal mine operators to establish medical surveillance programs to provide periodic health examinations at no cost to miners. The exams are similar to the medical surveillance programs available to coal miners under existing standards. 
• Replaces an outdated standard for respiratory protection with a new standard reflecting the latest advances in respiratory protection and practices. This update will better protect miners against airborne hazards, including silica dust, diesel particulate matter, asbestos and other contaminants. 

To learn more about the final rule visit MSHA.