Skip to content
[April 30, 2007 (Volume 72, Number 82)]
[Unified Agenda]

Department of Labor (DOL)
Mine Safety and Health Administration (MSHA)
Proposed Rule Stage



Priority: Other Significant

Legal Authority: 30 USC 811; 30 USC 813

CFR Citation: 30 CFR 57

Legal Deadline: None

Abstract: On May, 18, 2006, MSHA promulgated its final rule on Diesel Particulate Matter (DPM) Exposure of Underground Metal and Nonmetal Miners (71 FR 28924), phasing in the final diesel particulate matter (DPM) exposure limit over a 2-year period, with the final limit of 160 TC [micro]/m3 to become effective on May 20, 2008. The DPM exposure limit is expressed in terms of a ``TC'' or ``total carbon'' limit. MSHA is initiating a new rulemaking to establish the most appropriate measure for determining compliance with the final DPM exposure limit. Using the latest available evidence, MSHA will be examining the most appropriate conversion factor for a comparable elemental carbon (EC) limit. An EC measurement ensures that a TC exposure limit is valid and not the result of environmental interferences.

Statement of Need: The May 18, 2006 final rule at 30 CFR 57.5060(b)(3) requires mine operators to ensure that the miners' personal exposures to diesel particulate matter (DPM) in an underground mine do not exceed an airborne concentration of 160 micrograms of total carbon per cubic meter (TC [micro]/m3) of air during an average 8-hour equivalent full shift, effective May 20, 2008. This rulemaking proposes the EC conversion factor for the 160 TC [micro]/m3 limit, which would allow mine operators to implement the requirements of the May 18, 2006 final rule.

Summary of Legal Basis: Promulgation of this regulation is authorized by section 101 of the Federal Mine Safety and Health Act of 1977.

Alternatives: This rulemaking would amend and improve health protection from that afforded by the existing standard.

Anticipated Cost and Benefits: MSHA will prepare estimates of the anticipated costs and benefits associated with the selected conversion factor.

Risks: A number of epidemiological studies have found that exposure to diesel exhaust presents potential health risks to miners. These potential adverse health effects range from headaches and nausea to respiratory disease and cancer. In the confined space of the underground mining environment, occupational exposure to diesel exhaust may present a greater hazard due to ventilation limitations and the presence of other airborne contaminants, such as toxic mine dusts or mine gases. MSHA believes that the health evidence forms a reasonable basis for reducing miners' exposure to diesel particulate matter. Proceeding with a separate rulemaking to determine the correct TC to EC conversion factor for the phased-in final limits will more effectively reduce miners' exposures to DPM.


Action                            Date                      FR Cite


NPRM                            09/00/07
Final Action                    05/00/08

Regulatory Flexibility Analysis Required: No

Small Entities Affected: Businesses

Government Levels Affected: None

URL For More Information:

URL For Public Comments:

Agency Contact: Patricia W. Silvey, Director, Office of Standards,
Regulations, and Variances, Department of Labor, Mine Safety and Health
Administration, 1100 Wilson Boulevard, Room 2350, Arlington, VA 22209-3939
Phone: 202 693-9440
Fax: 202 693-9441

RIN: 1219-AB55