Purpose

To assist employers, workers and other workplace parties with understanding the requirements in Regulation 854 (Mines and Mining Plants) under the Occupational Health and Safety Act (OHSA), for the purpose of sampling diesel particulate underground.

Objectives

  • To provide information on sampling of diesel particulate matter (DPM) in underground mines.
  • To minimize and control the exposure of workers to diesel particulate matter.
  • To clarify the recommended use of the NIOSH 5040 Method for DPM sampling.

Legal requirements

In addition to the general requirements in the OHSA:

Underground requirements

Sections 183.1 and 183.2 of Regulation 854 (Mines and Mining Plants) under the OHSA cover the important requirements.

Other requirements

Sections 181.1, 182, and 183 of Regulation 854 (Mines and Mining Plants) under the OHSA cover the important requirements.

Background information

The Respirable Combustible Dust (RCD) method is non-selective and interferences such as oil mists, cigarette smoke and mineral dust could be measured indiscriminately as total carbon and contribute to what appears to be diesel exposure. In addition, research has shown that the RCD method is not recommended for compliance measurements in jurisdictions where the exposure limit is less than 0.6 mg/m³.

As more information became available, it was evident that diesel particulate matter (DPM) continues to be a significant health risk. The most accurate measurement to reflect the amount of DPM produced by a diesel engine was to measure the elemental carbon portion of the total carbon produced.

The lower limit of 0.4 mg/m³ for total carbon set out in clause 183.1(5)(a) or based on elemental carbon set out in clause 183.1(5)(b) will require a more accurate analytical method than the current RCD method. The accepted method, in North America, is the NIOSH 5040 which accurately measures both the elemental and organic carbon portions of the total carbon found in mines.

Acceptable practices for sampling DPM in underground mines

1.0 Sampling

The intent of this section is to provide information for sampling of DPM in underground Ontario mines according the NIOSH 5040 method. The RCD Analytical Method does not provide the level of accuracy required to determine compliance with the current prescribed limit of exposure. To sample for Total Carbon (TC), use of the NIOSH 5040 method, as described below, is recommended.

  • A 37 mm, pre-ashed quartz membrane filter is used.
  • Inserted into a 3 piece cassette with a back-up pad (the back-up pad is another pre-ashed filter to prevent TC contamination).
  • For quality control and simplicity it is advised to obtain preloaded sampling cassettes from the laboratory that will perform the analysis.
  • A 10 mm diameter nylon cyclone is used to remove large dust particles that could interfere with the analysis for quality control purposes.
  • The sampling pump is calibrated to provide a constant flow of 1.7 litres per minute through the filter.
  • Standard industrial hygiene practice for personal exposure monitoring should be followed.
  • It is recommended that a consistent format be used to record the results of testing that includes:
    • Sample date
    • Location of sample
    • Time that the pump ran
    • Name of worker sampled
    • Task being performed
    • Hours that tasks are performed
    • Equipment used around the worker being sampled
    • Amount of ventilations in the sampling area
    • Sample results
    • Comments that can be used for clarification once sample results are obtained

2.0 Analysis

2.1 Sample filter cassettes should be sent to a laboratory proficient in the NIOSH 5040 method.

Source : “Elemental Carbon (Diesel Particulate)”, Method 5040, Issue 3, 15 March 2003, NIOSH Manual of Analytical Methods, Fourth Edition.

3.0 Evaluation and interpretation

3.1 The laboratory analyzing the samples using the NIOSH 5040 Method will report results in both elemental and organic carbon fractions. Adding these fractions together gives the total carbon. The requirements that came into force on January 1, 2012 permit compliance by reference to either a measurement of ‘total carbon’ or by use of a calculation based on the measurement of elemental carbon found in diesel exhaust.

Example: Mine Sample # 1

TOTAL CARBON

= Elemental Carbon Reported + Organic Carbon Reported

= 0.3 mg/m³ + 0.12 mg/m³

= 0.42 mg/m³

0.42 mg/m³ is greater than the allowed limit of 0.4 mg/m³ of air

Application of clause 183.1 (5)(b) of Reg.854 allows for the use of the measurement of elemental carbon for determining compliance with the exposure limit by use of the following formula:

ELEMENTAL CARBON PORTION

= Elemental Carbon × 1.3

= 0.3 mg/m³ × 1.3

= 0.390 mg/m³

COMPLIANT: 0.390 mg/m³ is less than the allowed limit of 0.4 mg/m³ of air

3.2 The information obtained from the worker being sampled and the observations from the person in charge of the sampling are combined with the results. This allows everyone at the mine to obtain a clear idea of the physical conditions during the shift and how it affected the exposure of the worker being sampled.

3.3 The results of testing must be recorded (subsection 183.2(3) of Reg. 854) and results given to the Joint Health and Safety Committee or the health and safety representative (subsection 183.2(2) of Reg. 854).

3.4 It can be beneficial to compare with previous results for trending of DPM exposure.

Resources

Workplace Safety North (WSN) has a manual of ventilation practices useful to workplace parties looking for information. Contact WSN for a copy of the “Auxiliary Mine Ventilation Manual”.

Mines can refer to the paper, “Sampling for Diesel Particulate Matter in Mines” [PDF/324Kb], produced as part of the Diesel Emissions Evaluation Program, by CANMET – Mining and Mineral Sciences Laboratories, Report MMSL 01-052 (TR), October 2001.

Information for developing a strategy of diesel engine maintenance can be found in the “Maintenance Guideline and Best Practice for Diesel in Underground Mining” [PDF/494Kb]. The guide provides information on developing a maintenance program for diesel engine fleets.

A summary of health effects can be found in “Diesel Particulate Matter Exposure of Underground Metal and Non-metal Miners; Final Rule”, Department of Labor, Mining Safety and Health Administration, 30CFR Part 57, U.S. Federal Register, June 6, 2005. This source cites:

  • 6 studies between 2000 and 2002 showing a link between DPM and human respiratory and immunological effects
  • 5 studies between 1999 and 2002 showing a link between DPM and asthma
  • 5 studies between 2000 and 2002 showing a link between DPM and cardiovascular and cardiopulmonary effects
  • 3 studies between 2000 and 2002 showing a link between DPM and lung cancer. A statistically significant increase in risk of lung cancer was found among men exposed to diesel exhaust.
  • 15 studies between 2000 and 2002 which lend some degree of support that DPM may also cause other toxicological effects (immunological, allergic, inflammation, mutagenicity, induction of free oxygen radicals, airflow obstruction, impaired lung clearance, reduced defence mechanisms and cardiovascular effects).

More information

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based on the facts they find in the workplace.