4 November 1998

The US Department of Labor's Mine Safety and Health Administration (MSHA) proposed new rules that establish health standards for underground metal and nonmetal mines (or non-coal mines) that use equipment powered by diesel engines. The new standards are intended to reduce risks to underground metal and nonmetal miners from health hazards associated with exposure to high concentrations of diesel particulate matter.

Average concentrations of diesel particulate matter, or DPM, observed in underground mines that use diesel equipment are up to 200 times as high as average environmental exposures in the most heavily polluted urban areas and up to 10 times as high as exposures estimated for other occupational groups, such workers inside bus repair facilities. MSHA believes that the DPM exposure puts miners at significantly increased risk of incurring serious health problems, including lung cancer.

The new proposal would establish a concentration limit for diesel particulate matter and require mine operators to use engineering or work practice controls to reduce DPM to that limit. The rule establishes a concentration limit that would be phased in over a five-year period. An interim limit of 400 micrograms per cubic meter of air measured as total carbon would go into effect following an 18-month period of MSHA education and technical assistance to mine operators. A final limit of 160 micrograms per cubic meter of air would become effective in five years.

Under the proposal, mine operators would be required to provide certain information annually to miners to increase the awareness of those who may be exposed to diesel exhaust emissions. Subjects to be covered include health risks associated with exposure to diesel particulate matter; methods used to control DPM concentrations; identification of personnel responsible for maintaining those controls; and actions miners must take to ensure controls operate as intended.

Of the approximate 260 underground metal and nonmetal mines in the US, 203 use diesel-powered equipment. There are about 4,100 pieces of diesel-powered equipment currently in use. Approximately 17,000 miners will require training under the proposed rule. MSHA estimates that the rule will cost metal and nonmetal mine operators about $19 million annually. Of that amount, large mine operators would incur, as a group, approximately $14.6 million. Small mine operators, those employing fewer than 20 workers, would incur a cost of $4.6 million annually.

On 29 October 1998, the proposed rule was published in the Federal Register. The publication initiated a period of comments on the proposed rule. Interested parties may submit comments by mail, telefax, or electronic mail. The mailing address for comments is MSHA, Office of Standards, Regulations, and Variances, 4015 Wilson Blvd., Room 631, Arlington, Va., 22203. The electronic mail address is comments@msha.gov. The telefax number is 703-235-5551. Comments must be received prior to 26 February 1999.

Contact: Rodney Brown, MSHA, (703) 235-1452
Regulatory Text (pdf)