On June 6, MSHA published the Diesel Particulate Matter Exposure of Underground Metal and Nonmetal Miners Rule. The rule changes the way MSHA calculates diesel particulate matter emission limits in underground mines. According to the agency, the new calculations, based on permissible exposure limits measured by elemental carbon, are comparable to the former measurements, which measured limits based on total carbon emissions. In comments filed on behalf of the United Mine Workers of America, however, Advanced Technologies and Laboratories International senior scientist James Weeks points out that the new emissions standards are actually weaker than the older standards. By basing emission standards on elemental carbon rather than total carbon emissions, the new emissions standard will no longer capture the hundred of organic compounds combined with diesel particulate matter, many of which are carcinogenic.

The new regulation also contains other provisions that weaken the protection and could ultimately render the regulation impotent. Mines will be able to receive an unlimited number of one-year special extensions, administered by an MSHA district manager. Moreover, the new regulation now requires the agency to consider economic feasibility rather than just technical feasibility when considering special extensions for compliance with the rule. This new provision could open a floodgate of special extensions that will allow mines to avoid implementing the emissions standards altogether.

MSHA originally established the health standard using total carbon emissions on Jan. 19, 2001. Industry challenged the rule and organized labor intervened. The settlement agreement that followed required MSHA to promulgate a further series of rules addressing specific issues, including several that are addressed in this rulemaking. The new standard is an interim final rule. MSHA is required to create a more stringent standard in 2006, revising the concentration limit to 160 micrograms per cubic meter of air.

Read comments on the regulation by the United Mine Workers of America and the Center for Progressive Reform.

Posted by Genevieve Smith