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What is Diesel Engine Exhaust (DEE)? 

The truth about DEE | Cancer Council

Diesel engine exhaust and cancer

Diesel engine exhaust (DEE) is created by burning diesel fuels. It contains a mixture of gases and soot that cancer-causing agents (carcinogens) may stick to. These can easily travel deep into the lungs when you breathe them in. Chemicals in DEE increase your risk of developing long-term health problems, including lung cancer and possibly bladder cancer

In Australia, DEE is the second most common carcinogen workers are exposed to, behind ultraviolet (UV) radiation exposure. Around 1.2 million people in Australia are exposed to DEE at work every year.  

There is a risk of exposure to DEE for anyone working with or around diesel-powered engines, especially in confined spaces. Workers in mining, construction, agriculture, transport, and vehicle maintenance are most likely to be exposed. 

Learn more about diesel engine exhaust exposure in Australia, the health risks of exposure and the control measures available to protect workers via Professor Tim Driscoll in our Diesel Engine Exhaust: Let's clear the air webinar.  

Diesel Engine Exhaust: Let's clear the air webinar | Cancer Council

Airborne contaminants

DEE contains gases and soot, also called particulate matter. Other substances, including carcinogens, may stick to the soot. Because soot particles are very small, they can easily travel deep into the lungs causing a range of short-term and long-term health problems, including cancer. 

Regular exposure to high levels of soot, over a long period of time, increases the risk of getting lung and potentially bladder cancer. 

Cancer risk from DEE varies depending upon: 

  • where the engine is being operated (outside or enclosed space). 
  • ventilation in the workspace. 
  • number of engines. 
  • type and age of the engine. 
  • size of engines. 
  • fuel pump setting. 
  • engine temperature. 
  • fuel used (e.g., low-sulphur diesel). 
  • use of emission control system/s. 
  • state of engine tuning and maintenance. 
  • pattern of use (load and acceleration). 
  • length of time the worker is exposed. 

Each year, roughly 130 Australians are diagnosed with lung cancer caused by work-related exposure to DEE. Not all workers will develop lung cancer, but the risk increases if you are exposed over many years or at very high levels.

Effective controls

All Australian workplaces must follow work health and safety laws. These vary slightly between states and territories, but the duty of care for employers and responsibilities of workers across Australia is similar: 

  • employers are required to ensure the health and safety of their workers at their workplace. 
  • workers must take care of their own health and safety. 
  • workers must not negatively affect the health and safety of other people. 
  • workers must follow any reasonable instruction and workplace health and safety policies. 
  • workers should always be involved in the risk management process to correctly identify hazards and use control measures that suit the workplace. 

You should eliminate or reduce exposure to hazards using the hierarchy of control (Figure 1) and put in place a risk management process. If suitable control measures are not in place, anyone working with, or around diesel-powered engines has an increased risk of developing lung cancer.

Figure 1. Hierarchy of control 

The Australian Institute of Occupational Hygienist’s Diesel Particulate Matter and Occupational Health Issues Position Paper recommends workplace exposure limits that help to reduce the irritant effect of DEE. However, the limit in this paper is higher than the level of DEE which is associated with cancer. 

Workplace air monitoring can be used to check if exposure to particulate matter in DEE is being effectively reduced by the controls you are using. An occupational hygienist can assist with air monitoring. 

For any concerns related to control measures at your workplace, or for more information on the control of air quality contact: 

  • your workplace supervisor or management (if you're an employee). 
  • your workplace health and safety representative or union representative. 
  • state and territory work health and safety regulators. 
  • Safe Work Australia. 

The Safe Work Australia Guidance for Managing the Risks of Diesel Exhaust has information on how you can control DEE hazards in your workplace. A combination of the recommended controls should be used (Table 1) to minimise DEE exposure. You should choose the control measures that best suit your workplace.

Table 1. Summary of control measures for diesel engine exhaust

Engine selectionReplace diesel powered engines with other energy sources (i.e., electric, gas) or choose low emission engines. Use purchasing guidelines for supply of engines that meet US Tier 4 or Euro 6 standards. 
Fuel selectionUse ultra-low sulphur and other low-emission diesel fuels, fuel additives and low sulphur lubricants where possible. Avoid contaminating diesel fuel and lubricating oils. 
Engine refurbishmentInstall devices that reduce emissions (e.g., particulate filters, catalytic converters, water scrubbers). 
Emission control devicesInstall devices that reduce emissions (e.g., particulate filters, catalytic converters, scrubbers, acoustic agglomeration, cyclones). 
Enclosed equipmentDesign and maintain air-conditioned cabs where possible (positive pressure, high-efficiency particulate air (HEPA) filtered air supply, leak tested). 
VentilationUse both local exhaust and forced dilution ventilation. Natural ventilation should not be used as a control method. Use connecting extraction pipes for vehicle exhausts in workshops. Cold engine starts should occur in spaces with good ventilation. 
Maintenance and repairsHave a maintenance schedule for all engines and emission control equipment. Carry out emissions-based maintenance on engines (initial baseline testing and raw exhaust monitoring). 
Testing of exhaust componentsUse raw exhaust tests to measure how well exhaust treatments are working. Test in normal working conditions (e.g., engines under load, in low gear with hot engine and hydraulics, engine revving at 70-80%). High and low idle tests are not enough. 
Engine operationOperate engines to optimise combustion (e.g., drive to usual conditions, limit idling and over-revving). Turn off engines when not in use. 
Worker education and trainingEducate workers on hazards and the policies and procedures used to manage them. This is a work health and safety requirement. 11 Report any changes in engine emissions or visible changes in the workplace (i.e., visible white, blue or black smoke, walls or surfaces covered in soot or smoky looking haze when diesel engines are in use). 
Share activitiesRotate job tasks between your workers to reduce amount of time exposed to diesel engine exhaust. 
AdministrativeSchedule work to minimise the number of workers near the plant whilst it is operating. 
Personal protective equipment (PPE)Wear air supplied or air purifying respiratory protection that filters particulates. They should be fitted to each worker. 

How do I detect cancer early and reduce my cancer risk? 

Speak to your doctor if you’ve had a cough for more than three weeks or have blood in your urine. To find out what you can do to create a workplace that supports healthy choices to help reduce cancer risk, contact Cancer Council 13 11 20

Where can I get reliable information?

Other useful websites

Australian Institute of Occupational Hygienists: Position Paper – Diesel particulate matter and occupational health issues

US Department of Labor Mines Safety and Health Administration: Practical ways to reduce exposure to diesel exhaust in mining – a toolbox

UK Health and Safety Executive: Control of diesel engine exhaust emission in the workplace

UK Institution of Occupational Safety and Health: Diesel exhaust emissions resource pack


  • International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2013, World Health Organisation: Lyon, France.
  • Carey, R.N., et al., Estimated prevalence of exposure to occupational carcinogens in Australia (2011-2012). Occupational and Environmental Medicine, 2014. 71(1): p. 55-62.
  • Peters, S., et al. The Australian Work Exposures Study: Prevalence of Occupational Exposure to Diesel Engine Exhaust. Annals of Occupational Hygiene, 2015. 59(5): p. 600-608.
  • Australian Institute of Occupational Hygienists. Diesel Particulate Matter and Occupational Health Issues – Position Paper. 2013: Keilor Park, VIC.
  • HE, W. Diesel exhaust particulates. Inhalation toxicology. 2014. 19(1): p. 241-244.
  • Ris, C. U.S. EPA Health Assessment for Diesel Engine Exhaust: A Review. Inhalation Toxicology. 2007. 19: p. 229-239.
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  • Ullman, Terry L.  Investigation of the Effects of Fuel Composition on Heavy Duty Diesel Engine Emissions. SAE Technical Paper No. 892072. 1989, Warrendale, PA: Society of Automotive Engineers.
  • Safe Work Australia. Guide to managing risks of exposure to diesel exhaust in the workplace. 2015, Safe Work Australia: Canberra, ACT.
  • Model Work Health and Safety Act 2011. Safe Work Australia. Government of Australia. Canberra, ACT.
  • Safe Work Australia. How to manage work health and safety risks – Code of Practice. 2011, Safe Work Australia: Canberra, ACT.
  • Health and Safety Executive, U.K. Control of diesel engine exhaust emissions in the workplace, 3rd ed. 2012, UK HSE: Merseyside, UK.
  • WA Department of Mines-and Petroleum. Guideline – Management of diesel emissions in Western Australian mining operations. 2013, WA Department of Mines and Petroleum: East Perth, WA.

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