Department of Labor Updates Diesel Particulate Matter Regulations for Underground Coal Mines

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In June 2026, the Department of Labor’s Mine Safety and Health Administration (MSHA) issued a significant regulatory update affecting underground coal mining operations across the United States. If your business operates diesel-powered equipment in underground coal mines, understanding this change is essential for maintaining compliance and avoiding costly penalties.

What Is This Regulatory Update?

MSHA has eliminated outdated requirements for diesel particulate matter (DPM) emission limits that previously applied to permissible diesel-powered equipment and non-permissible heavy-duty diesel-powered equipment in underground coal mines. The agency removed these regulations because they contained outdated effective dates that were no longer applicable or enforceable.

This modernization streamlines MSHA’s regulatory framework by removing obsolete language and requirements that had become impractical or superseded by newer standards. Rather than implementing new stricter emission limits, MSHA is cleaning up its administrative requirements to reflect current industry practices and technological standards.

Which Businesses Are Affected?

This regulatory change primarily impacts underground coal mining companies that operate diesel-powered equipment. If your organization manages underground coal mining operations using heavy-duty diesel machinery, you need to review your current compliance documentation and operational procedures.

Small to mid-sized mining operations are particularly affected, as are HR and compliance managers responsible for worker safety and regulatory adherence. Contractors supplying equipment or services to underground coal mines should also monitor this change closely.

What Must Employers Do to Comply?

The removal of outdated DPM emission requirements actually simplifies compliance for most operators. However, your organization should take proactive steps to ensure you’re not accidentally following superseded regulations. Review your current safety protocols, equipment specifications, and employee training materials to eliminate references to outdated DPM limits.

Update your written compliance procedures and ensure all staff understand that certain previous requirements are no longer enforceable. This is an excellent opportunity to conduct a comprehensive audit of your safety documentation and modernize your approach to equipment standards.

Three Practical Compliance Steps

Step 1: Audit Your Current Documentation

Review all equipment specifications, operational manuals, and safety procedures currently in use. Identify any references to the eliminated DPM emission limits and remove obsolete language. Consider using BambooHR HR software to centralize and organize all compliance documentation, making it easier to track updates across departments.

Step 2: Update Employee Training Materials

Revise all training programs, safety manuals, and onboarding materials that previously referenced the outdated DPM requirements. Ensure new hires and existing employees understand current expectations without confusion about superseded regulations.

Step 3: Create Updated Equipment Policies

Develop clear written policies reflecting current standards for diesel-powered equipment operation. For comprehensive employment agreement templates that address equipment use and safety compliance, LegalZoom employment agreements provide professional templates customizable for your organization’s needs.

Moving Forward

This regulatory update represents MSHA’s commitment to maintaining relevant, enforceable standards in the mining industry. By taking these three practical steps now, your organization can ensure smooth compliance and demonstrate your commitment to worker safety and regulatory adherence.

For more information, visit the full rule on the Federal Register at the document number 2026-12792.