(CN) - The D.C. Circuit upheld a federal standard aimed at reducing diesel exhaust in mines, despite industry efforts to prevent its implementation.
The National Mining Association and other industry groups challenged a 2006 rule that implemented, by 2008, stricter measures preventing accumulation of diesel exhaust in mines.
Diesel exhaust, which has negative health effects and may be carcinogenic, accumulates quickly in mines, where ventilation is often scarce.
The rule was originally intended to switch the measuring standard from total carbon to elemental carbon. Filters assess both elemental and organic carbon concentrations in the air, which are then added to calculate total carbon. Although elemental carbon is ultimately considered to be a better measure than total carbon, the lack of scientific data ensuring a constant conversion factor led the Mine Safety and Health Administration to eventually scrap the switch.
The mining industry claimed this amounted to formulating a new regulation without going through proper rule-making channels.
Writing for the three-judge panel, Judge Judith Rogers stated that ample evidence exists to support the total carbon standard, particularly in light of the agency's inability to find a constant conversion factor for lower levels of total carbon.
The agency's "pledge" to convert the standard was conditioned on data that could not be acquired, the court ruled. Such need for study does not constitute new rule-making, the D.C. Circuit concluded.
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