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DOL/MSHA RIN: 1219-AB55 Publication ID: Fall 2007
Title: Diesel Particulate Matter: Conversion Factor From Total Carbon to Elemental Carbon
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 micrograms of total Carbon per cubic meter of air 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.

Agency: Department of Labor(DOL) Priority: Other Significant
RIN Status: Previously published in the Unified Agenda Agenda Stage of Rulemaking: Proposed Rule Stage
Major: No Unfunded Mandates: No
CFR Citation: 30 CFR 57
Legal Authority: 30 USC 811; 30 USC 813
Legal Deadline: None

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 DPM in an underground mine do not exceed an airborne concentration of 160 micrograms of total carbon per cubic meter 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 limit, which would allow mine operators to implement the requirements of the May 18, 2006 final rule.

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

Alternatives: MSHA will also analyze and evaluate options to convert the final PEL of 160 ug/m3 of TC to a comparable final EC-based PEL.

Anticipated Costs 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 11/00/2007
Final Action 05/00/2008

Regulatory Flexibility Analysis Required: No Government Levels Affected: None
Federalism: No
Energy Effects: No Included in the Regulatory Plan: Yes
RIN Information URL: Public Comment URL:
Initial (Administrative Startup and /or Capital) Cost: $0 Yearly (Annual Operating) Cost: $0
Agency Contact:
Patricia W. Silvey
Director, Office of Standards, Regulations, and Variances
Mine Safety and Health Administration
Room 631,1100 Wilson Boulevard,Room 2350
Arlington,VA 22209-3939
Phone:202 693-9440
Fax:202 693-9441