ISSUE DATE: 5/16/2011

PROGRAM INFORMATION BULLETIN NO. P11-38 

FROM: KEVIN G. STRICKLIN

Administrator for 

Coal Mine Safety and Health

NEAL H. MERRIFIELD

Administrator for

Metal and Nonmetal Mine Safety and Health

LINDA F. ZEILER

Acting Director of Technical Support

SUBJECT: Re-Issue of P02-04 - Potential Health Hazard Caused by PlatinumBased Catalyzed Diesel Particulate Matter Exhaust Filters

Scope

This Program Information Bulletin affects underground coal and metal and nonmetal 

mine operators using diesel-powered equipment, manufacturers of diesel-powered 

underground mining equipment, including exhaust after-treatment devices and 

systems, ‘miners’ representative’ and Mine Safety and Health Administration (MSHA) 

enforcement personnel.

Purpose

The purpose of this bulletin is to inform mine operators of a potential health hazard 

caused by currently available platinum-based catalyzed diesel particulate matter (DPM) 

exhaust filters for diesel-powered equipment. Use of these type filters may result in 

increased production of nitrogen dioxide (NO2) gas, as compared to NO2 emissions 

produced by engines operating without these type filters, causing miners to be exposed 

to increased concentrations of NO2. Symptoms of overexposure to NO2 include 

irritation to the eyes, nose and throat, cough, decreased pulmonary function, chronic 

bronchitis, breathing difficulty, chest pain, pulmonary edema, and rapid heartbeat. 
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Background

The MSHA standard at Title 30, Code of Federal Regulations, Section 72.501 

(30 C.F.R. § 72.501) establishes a schedule requiring that coal mine operators meet 

certain emission specifications for nonpermissible heavy-duty diesel-powered 

equipment in underground coal mines. At 30 C.F.R. § 57.5060, MSHA requires 

operators of metal and nonmetal underground mines to limit DPM concentration where 

miners normally work or travel. Mine operators most likely have to use DPM filters to 

meet these MSHA requirements. 

A common type of DPM filter is the ceramic (Cordierite® or silicon carbide) wall-flow 

monolith. These filters are either catalyzed (containing precious or base metal) or noncatalyzed. Catalyzed filters offer the advantage of low-temperature on-board 

regeneration (removal of trapped soot from the filter) accomplished through the 

utilization of exhaust gas heat. Non-catalyzed or base metal catalyzed filters may 

require removal from the machine for cleaning, but may, in some cases, be regenerated 

on board. 

In addition to DPM standards, the concentration of NO2 in underground mining 

environments may not exceed a ceiling value of 5 parts per million (ppm) as established 

in MSHA standards at 30 C.F.R. § 57.5001 (Metal/Nonmetal) and 30 C.F.R. § 75.322 

(Coal).

‘This program information bulletin is updated with current contact persons’ 

information.’

Information

Thus far, MSHA has tested six precious metal (platinum) catalyzed filters at its diesel 

laboratory and has determined that each of them increases the amount of NO2 emitted 

by one MSHA-approved diesel engine, as compared to the same engine operating 

under identical test conditions, but without the catalyzed filter. The increase is 

attributed to the oxidation of nitric oxide (NO) due to the presence of the platinum 

catalyst. The concentrations of NO2 obtained through the installed platinum catalyzed 

filters reached levels that could not be diluted to or below 5 ppm using the engine’s 

approved gaseous name plate air quantity. The gaseous name plate air quantity is the 

amount of ventilation air necessary to reduce the engine emission gaseous 

concentrations to or below these specified levels: NO to 25 ppm, NO2 to 5 ppm, CO 

(carbon monoxide) to 50 ppm and CO2 (carbon dioxide) to 5000 ppm based on a 

laboratory test cycle. This air quantity is listed on the engine’s approval plate which is 

attached to the engine.
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MSHA will continue to test additional filters and release the results to the mining 

community. Manufacturers are developing catalyst formulations which may overcome 

the NO2 problem, possibly by lowering the platinum content of the traps or by using 

other catalytic formulations. MSHA maintains a list of manufacturers who can supply 

filters on its Internet web site at:

http://www.msha.gov/01-995/Coal/DPM-FilterEfflist.pdf

Note that MSHA has included a cautionary statement on this list concerning the 

potential health hazard associated with the available catalyzed DPM filters. The listed 

manufacturers can assist the mine operators in selecting a filter system to meet MSHA 

requirements. Please contact MSHA Technical Support for additional information on 

DPM filters.

Recommended Action

To determine whether the catalyzed filter is causing an increase in NO2 that might 

adversely affect the mine’s air quality, the machine should be operated in an entry that 

provides the engine’s name plate air requirement, or the minimum quantity of air that 

the machine can work in. The machine should be operated under its normal working 

cycle and NO2 levels should be monitored downstream from the machine. The NO2

concentration should not exceed 5 ppm when tested. MSHA representatives are 

available to assist mine operators with this test.

Platinum-based catalyzed DPM filters that cause a MSHA-approved engine or a nonapproved engine to produce NO2 emission levels that cannot be diluted to or below 

5 ppm, utilizing either the:

• MSHA name plate air quantity established for the engine, or

• Minimum quantity supplied where that engine operates

should be removed and replaced with a DPM control device that does 

not increase NO2 levels. MSHA intends to issue enforcement policy in 

the near future allowing affected mine operators a reasonable amount 

of time to comply with applicable MSHA standards.

Authority

Federal Mine Safety and Health Act of 1977; 30 C.F.R. Parts 7, 36, 57, 72 and 75.

Issuing Offices and Contact Persons

Coal Mine Safety and Health, Health Division

Robert Thaxton (202) 693-9515

E-mail: thaxton.robert@dol.gov
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Metal and Nonmetal Mine Safety and Health, Health Division

Reginald J. Richards, DrPH, CIH (202) 693-9600

E-mail: richards.reginald.j@dol.gov

Technical Support, Approval and Certification Center

John Faini (304) 547-2029

E-mail: faini.john@dol.gov

Internet Availability

This information bulletin may be viewed on the Internet by accessing MSHA’s home 

page at http://www.msha.gov and choosing”Compliance Info”and “Program 

Information Bulletins.”

Distribution

All Program Policy Manual Holders

Mine Operators

Independent Contractors

Special Interest Groups