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NIOSH Respiratory Diseases Research Program

Evidence Package for the National Academies' Review 2006-2007

NIOSH Programs > Respiratory Diseases > Evidence Package > 5. Respiratory Malignancies > 5.4 Lung Cancer Induced by Diesel Engine Exhaust

5.4c) Control Technology Research in Support of Diesel Rule Implementation

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Following MSHA’s 2001 promulgation of a rule regulating diesel particulate matter exposure of metal/nonmetal miners, the mining industry doubted whether it was possible to comply using existing control technology. Many of the proposed controls had only been tested in the laboratory. The industry asked RDRP scientists to conduct studies in underground mines to determine the effectiveness of diesel emissions controls under more realistic conditions and to determine if any other adverse health or safety impacts could result from their application.


RDRP scientists agreed to perform in situ testing if the control technology could be tested in isolation. The research was performed under a Metal/Nonmetal Diesel Partnership consisting of RDRP, MSHA, industry, and labor. Stillwater Mining Company's Nye Mine in Montana offered the use of a long drift ventilated by fresh air to conduct the studies. A single diesel-powered vehicle ran a representative and reproducible duty cycle within this isolated drift as air contaminant measurements were obtained. Comparisons were made between air contaminant concentrations when the vehicle was operated with and without various control technologies. The effects of the following technologies were measured:

  • Two blends of yellow grease biodiesel fuel
  • Two blends of soy-based biodiesel fuel
  • Cold- and warm-weather formulations of a water-fuel emulsion
  • Number one versus Number two diesel fuel
  • An ultra-low sulfur Number two fuel
  • A diesel oxidation catalyst
  • Platinum-catalyzed particulate filters
  • A fuel-borne catalyzed particulate filter
  • High-temperature disposable pleated-element filters from two manufacturers

These studies were performed as two individual test sets during 2003-2004. Contaminants measured were CO2, CO, NO, NO2, and particulate matter (including total particle mass, elemental carbon, total carbon, and particle size distribution and number). Findings confirmed that reductions in contaminant concentrations reported in laboratory studies were achievable when applied to real equipment operated under simulated production cycles. The study also confirmed an increase in NO2 caused by platinum-catalyzed ceramic filters designed to facilitate the passive regeneration at lower-duty cycle temperatures. The elevated NO2 emissions indicated a possible health hazard associated with the use of these filters in underground mines.

Outputs and Transfer

RDRP issued reports to the partnership detailing the research findings. Information from this study is being published in several journals (10 journal articles and a Web document) and presented at several conferences. The research results were also presented at two workshops and partnership meetings attended by representatives of industry, labor, and government (A5-40).

Intermediate Outcomes

In the recasting of the interim diesel exhaust rule for metal/nonmetal mines, MSHA referenced the 2004 RDRP/Stillwater study report as part of the evidence that available technologies are capable of reducing diesel exhaust particulate matter. The report, entitled "The Effectiveness of Selected Technologies in Controlling Diesel Emissions in an Underground Mine: Isolated Zone Study at Stillwater Mining Company's Nye Mine," is on the MSHA Web site at (External link) (A5-41). The information obtained from this research has given industry an increased level of confidence that the technology to reduce worker exposure to diesel exhaust particulate matter is available and operationally effective.

What’s Ahead

Research, expected to begin in the near future, is currently being planned by RDRP scientists to address long-term implementation issues relating to the MSHA diesel exhaust rule.