This document summarizes strategies to reduce worker exposure to diesel engine exhaust in mining industries. It begins by describing diesel exhaust as a human carcinogen and estimates that 560 lung cancers are caused by occupational exposure annually. It then introduces a "bowtie diagram" infographic developed to visually explain multiple exposure control options in mining in a proactive-reactive framework. The rest of the document discusses various exposure controls like alternative fuels, engine upgrades, ventilation, enclosed cabs, and respiratory protection. It concludes by discussing policy needs like lower exposure limits and calls for further research on the health impacts of different exhaust components and effectiveness of controls.

1. Exposure reduction strategies for diesel
engine exhaust in the mining industry
Kate Jardine
Occupational Cancer Research Centre
November 7, 2017

2. Diesel Engine Exhaust
2
Bugarski et al (2011). Diesel Aerosols and Gases in Underground Mines.
NIOSH Report of Investigations 9687.
IARC (2013). Monograph 105: Diesel and gasoline engine exhausts and
some nitroarenes.
• A highly variable
mixture of gases and
particulates
• Group 1 human lung
carcinogen (IARC)
– Suspected bladder
carcinogen
(EC)
(OC)

3. Occupational exposure to DEE
• 61,000 exposed workers in Canadian mining industry
(CAREX Canada)
– 23% are exposed at high levels

4. Occupational cancer due to DEE
• 560 lung cancers due to occupational DEE (all industries)
• 220 lung cancers among workers in the mining industry
4
The Burden of Occupational Cancer in Canada
Study is funded by the Canadian Cancer Society

5. Infographic of DEE Controls
• Developed for and funded by the Ontario
Ministry of Labour
• “Develop a Bowtie diagram that presents a clear
differentiation between proactive and reactive
risk management of diesel emissions in mining.”
– Simple, visual explanation of multiple plausible
controls
• Visual ‘menu’ of options
5

6. Bowtie Diagrams
• Generally used for acute events rather than
occupational hygiene risks
6

7. Bowtie Diagrams
• slide
7

8. Developing an Infographic
• Scope:
– Primary prevention, workplace-based controls
– Out of scope: government policy, surveillance, program
development
– Specifically focus on DPM
• Simple visual
• Incorporate a ranking of the controls
– Hierarchy of Controls
– Proactive vs Reactive
• Some cost information
8

9. Developing an Infographic
9

10. Developing an Infographic
10Source: US National Institute for Occupational Safety and Health

11. Infographic
11

12. Alternative Energy
• Electric
– Goldcorp’s Borden Lake mine
(Ontario)
• Hybrid diesel-electric
– 25-40% PM reduction in
CANMET-MMSL study
12
Laverdure et al. Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Magazine 2011.
US EPA. Verified Technologies List for Clean Diesel, 2016.
Proactive

13. Replace or Repower
• New engines emit less PM (Tier 1  Tier 4)
– 1975-1986 scraper  Tier 2: 81% PM reduction
13Scott et al. Cleaner Diesel Handbook, 2005.
US EPA. Verified Technologies List for Clean Diesel, 2016.
Proactive

14. Aftertreatment Systems
• Diesel Particulate Filters (DPFs)
– 80-99% PM reduction
– Not universally applicable, require
filter cleaning and maintenance
– $$$$
• Diesel Oxidation Catalysts (DOCs)
– 15-50% PM reduction
– Few limitations on use
– Cheaper
14
Bugarski et al. Environ Sci Technol 2009;43(17):6737-43.
Diesel Technology Forum 2003. Cleaner air, better performance.
Photo: Marxandrade via Wikimedia Commons
Proactive

15. Ventilation
• Improve airflow with:
– More fans in parallel or higher horsepower fans ($$$)
– New ventilation shafts or airways
– Stoppings or auxiliary fans
• Minimum ~100 cfm/BHP for majority of Canada
• Stakeholder feedback: emphasize reduction of
exposure to other hazards
15
Ontario Occupational Health and Safety Act: Regulation 854.
Bugarski et al (2011). Diesel Aerosols and Gases in Underground Mines.
NIOSH Report of Investigations 9687.
Reactive

16. Tele-Operation
• Distant control of equipment
• Operator can be on surface or completely off site
– Protected from many hazards
16
Paraszczak et al (2015). Int J Min Reclam Environ 29(5):391-403.
Fisher & Schnittger (2012). Autonomous and remote operation technologies in the
mining industry: benefits and costs. BAE Research Report 12.1.
Bugarski et al (2012). Controlling exposure to diesel emissions in underground mines.
• Other workers
still exposed
Reactive

17. Enclosed Cabs
• Reduce operator exposure by up to 90%
– Can be less than 40% efficient if not optimized
• Factors that affect function:
– Intake filter efficiency
– Use of recirculation filters
– Cab integrity
– Heat and A/C
– Prohibiting smoking
• No exposure reduction for nearby workers
17Bugarski et al (2011). Diesel Aerosols and Gases in Underground Mines.
NIOSH Report of Investigations 9687.
Reactive

18. Administrative Controls
Proactive:
• Preventive maintenance
– Up to 55% PM reduction
• Idling policies
Reactive:
• Scheduling and site planning
– Feedback: may not be realistic
• Operator training
18McGinn. Relationship between diesel engine maintenance and exhaust emissions. DEEP Final Report.
Proactive
and
Reactive

19. Respirators
• Stakeholder feedback: emphasize that respirators
should not take the place of other controls
• Effectiveness can vary:
– Type, fit, use
– Maintenance
– Facial hair
– Sweat or dust
– Working posture, hardhats
– Heavy breathing
19Sargent & Gallo (2003). ILAR Journal 44(1): 52-56.
Mayer & Korhonen (1999). Int J Occup Saf Ergon 5(3):347-360.
Reactive

20. What about biodiesel?
• Reduces DPM mass and EC fraction
– Approx. 50% reduction for 100% biodiesel
– Blends up to 20% can be used with minimal
modifications
• Health impact not well understood
– May increase OC fraction
– May increase number concentration
– Changes to size distribution
20
Mischler & Colinet. Proceedings of the 9th International
Mine Ventilation Congress. 2009, 2:879-888.
Bugarski, et al. J Air Waste Manag Assoc 60(2):237-44.

21. Outcomes and next steps
• Significant awareness within mining and health and
safety groups
– Workplace Safety North
– Occupational Health Clinics for Ontario Workers
– Occupational Disease Action Plan
• Requests for development in other sectors
– Construction
– On-road municipal services
– Differences in controls, reductions, language
21

22. Future needs
Policy
• Introduce an OEL for DEE in general workplaces
• Lower the exposure limit for the mining industry
Further research
• Impact of controls on DEE composition
• What components of DEE contribute to health
effects?
22

23. Exposure limits for DEE
Canada
• ON, QC: 400 ug/m3 TC (~307 ug/m3 EC) in mining
Finnish Institute of Occupational Health target levels:
• 20 ug/m3 (EC) for underground mining
• 5 ug/m3 (EC) for general workplaces
Dutch Expert Committee on Occupational Safety
• Under Review: No higher than background (1 ug/m3 EC)
23
Vermeulen et al. Environ Health Perspect 2014;122(2):172-177.
Vermeulen & Portengen. Occup Environ Med 2016;73(12):846-848.
Dutch Expert Committee on Occupational Safety of the health Council, https://www.gezondheidsraad.nl/en/node/5992
Total Carbon (TC) = EC + OC

24. Acknowledgements
Funding: Ontario Ministry of Labour
24
Paul Demers, Victoria Arrandale (OCRC)
Mike Russo (IHSA)
Jason Chevrier (WSN)
Jamie Cresswell, Rick Shulist, Bob Barclay, Sujoy Dey (MOL)