NIOSH Cuts Prompt MSHA to Pause Silica Rule Enforcement
MSHA will pause enforcement of its final rule on respirable crystalline silica for coal mine operators until Aug. 18, 2025, four months from the original compliance date, the agency announced in a recent notice to stakeholders. MSHA says the pause has to do with this month’s “unforeseen NIOSH restructuring,” among other reasons. Planned cuts to NIOSH set to take effect on June 1 will eliminate nearly all NIOSH programs and divisions and will reduce the agency’s workforce from approximately 1,400 full- and part-time employees to fewer than 150. MSHA’s “temporary enforcement pause” affects the requirements for coal mine operators set forth in 30 CFR part 60, which describes mandatory health standards for mines related to respirable crystalline silica.
“The silica rule requires mine operators to update their respiratory protection programs and may result in operators obtaining additional respirators and sampling devices,” MSHA’s notice states. “MSHA understands that recent [NIOSH] restructuring may impact the Pittsburgh Mining Research Division, the National Personal Protective Technology Laboratory, and the supply of approved and certified respirators and personal dust monitors.”
The pause is intended to allow time for coal mine operators to secure equipment and come into compliance, MSHA says. During this time, the agency plans to help accredited laboratories gain proficiency in MSHA analytical methods and provide other compliance assistance to the mining industry. According to MSHA, the pause does not affect the compliance date for metal and nonmetal mines, which is April 8, 2026.
MSHA’s silica rule lowered its permissible exposure limit for respirable crystalline silica to 50 µg/m3 as an eight-hour time-weighted average. As explained in an MSHA FAQ, the previous respirable crystalline silica PEL was 100 µg/m3 “reported as an equivalent full-shift TWA concentration as measured by the Mining Research Establishment (MRE) instrument.” This method of determining exposures provided no adjustment for extended work shifts. Under MSHA’s new silica rule, mine operators must use respirable particle size-selective samplers that meet the requirements of ISO 7708:1995, Air Quality—Particle Size Fraction Definitions for Health-Related Sampling. “The full-shift, 8-hour TWA calculation provides greater protection for coal miners,” the FAQ states.
For more information, see MSHA’s notice to stakeholders.
