MSHA continues enforcing existing silica exposure rules amid ongoing litigation

The Mine Safety and Health Administration (MSHA) will continue enforcing existing federal regulations on respirable crystalline silica and quartz exposure.

A program information bulletin (PIB) issued April 9 informed mine operators the agency will continue enforcing 30 CFR parts 56, 57, 70, 71, 72, 75, and 90.

The PIB impacts MSHA enforcement personnel, coal mine operators, metal and nonmetal (MNM) mine operators, miners, unions and miner representatives, and other interested parties.

New rule would have lowered permissible exposure limit

On April 18, 2024, MSHA published a new rule, “Lowering Miners’ Exposure to Respirable Crystalline Silica and Improving Respiratory Protection,” also known as the 2024 Silica Rule.

The new rule amended existing MSHA standards to better protect miners against occupational exposure to respirable crystalline silica. It also established 30 CFR part 60, a standalone standard for respirable crystalline silica which would have lowered the permissible exposure limit (PEL) for respirable crystalline silica at coal and MNM mines.

As part of the 2024 Silica Rule, MSHA made several conforming amendments in 30 CFR parts 56, 57, 70, 71, 72, 75, and 90 to align with the new part 60.

Part 60 took effect June 17, 2024, but the conforming amendments for coal mines were not scheduled to take effect until April 14, 2025, and for MNM mines until April 8, 2026.

Lower dust exposure limit rule delayed indefinitely

Following publication of the 2024 Silica Rule, industry groups filed petitions in the United States Court of Appeals for the Eighth Circuit.

On April 11, 2025, the Court issued an order “staying” the 2024 Silica Rule’s compliance deadlines, meaning the previous rules will stay in place until further notice.

In accordance with the Court order, MSHA delayed enforcement of the 2024 Silica Rule requirements and continues enforcing the existing standards in place before the changes were to take effect.

When the Court’s stay is resolved, MSHA will publish a notice in the Federal Register advising the public of the termination of the stay and any further action taken by the agency.

Rules in effect for metal & nonmetal mines

MSHA will continue to enforce the existing MNM standards in place at the time of the Court-ordered stay which remain unchanged and are preserved under the stay:

• 30 CFR §56.5001 and 30 CFR §57.5001 - Exposure limits for airborne contaminants
• 30 CFR §56.5005 and 30 CFR §57.5005 - Control of exposure to airborne contaminants

MSHA issued a notice in the Federal Register to delay the effective date of the conforming amendments to the existing MNM standards.

Rules in effect for coal mines

MSHA will continue to enforce the existing coal standards in place at the time of the Court-ordered stay:

30 CFR §70 - Mandatory Health Standards for Underground Coal Mines

• 30 CFR §70.2 - Definitions
• 30 CFR §70.101 - Respirable dust standard when quartz is present
• 30 CFR §70.205 - Approved sampling devices operation & air flowrate
• 30 CFR §70.206 - Bimonthly sampling for mechanized mining units
• 30 CFR §70.207 - Bimonthly sampling for designated areas.
• 30 CFR §70.208 - Quarterly sampling for mechanized mining units.
• 30 CFR §70.209 - Quarterly sampling designated areas.
• Tables 70-1 and 70-2 to Subpart C of Part 70

30 CFR §71 - Mandatory Health Standards for Surface Coal Mines and Surface Work Areas of Underground Coal Mines

• 30 CFR §71.2 - Definitions

• 30 CFR §71.101 - Respirable dust standard when quartz is present

• 30 CFR §71.205 - Approved sampling devices operation & air flowrate

• 30 CFR §71.206 - Quarterly sampling designated work positions

• 30 CFR §71.300 - Respirable dust control plan & filing requirements

• 30 CFR §71.301 - Respirable dust control plan approval by District Manager and posting

30 CFR §72 - Health Standards for Coal Mines

• 30 CFR §72.710 - Selection, fit, use, and maintenance of approved respirators
• 30 CFR §72.800 - Single, full-shift measurement of respirable coal mine dust

30 CFR §75 - Mandatory Safety Standards - Underground Coal Mine Ventilation

• 30 CFR §75.350 - Belt air course ventilation

30 CFR §90 - Mandatory Health Standards for Coal Miners Who Have Evidence of the Development of Pneumoconiosis

• 30 CFR §90.2 - Definitions
• 30 CFR §90.3 - Part 90 option, notice of eligibility, exercise of option.
• 30 CFR §90.100 - Respirable dust standard
• 30 CFR §90.101 - Respirable dust standard when quartz is present
• 30 CFR §90.102 - Transfer notice
• 30 CFR §90.104 - Waiver of rights, re-exercise of option
• 30 CFR §90.205 - Approved sampling devices operation & air flowrate
• 30 CFR §90.206 - Exercise of option or transfer sampling
• 30 CFR §90.207 - Quarterly sampling
• 30 CFR §90.300 - Respirable dust control plan & filing requirements
• 30 CFR §90.301 - Respirable dust control plan approval by District Manager and copy to part 90 miner

MSHA will issue a forthcoming notice in the Federal Register for coal to reprint these existing standards in 30 CFR, which remain unchanged and are preserved under the Court-ordered stay.