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National Safety Information Bulletin: Managing Risks of Diesel Exhaust Exposure in the Workplace

20/04/2021BY: Phil Cleverly


What is Diesel Exhaust?

Diesel exhaust comes from engines burning diesel fuel. It is a complex mixture of gases, vapours, liquid aerosols and particulate substances. These substances are the products of combustion. The main chemical components of diesel exhaust emissions are:

  • Gases and vapours–these are mostly the gases found in air like nitrogen, oxygen, water vapour and carbon dioxide. There are also hazardous chemicals like nitrous oxide, nitrogen dioxide, sulphur dioxide, and carbon monoxide

  • Fine particles known as diesel particulate matter (DPM) including fine carbon particles. Hazardous chemicals known as poly aromatic hydrocarbons (PAHs) adhere to the surface of the carbon particles. DPM can act like a gas and stay airborne for long periods of time. DPM can penetrate deep into the lungs because of its small size

Workplace Exposure to Diesel Exhaust:

The major source of workplace exposure to diesel exhaust on a mine site is from heavy vehicles that use diesel fuel like haul trucks, bulldozers and excavators.

Diesel exhaust may also be generated from stationary power sources like generators and winch motors including those mounted to vehicles.

Levels of exposure can be higher in enclosed, poorly ventilated areas where the concentration of exhaust can build up like in heavy vehicle repair workshops or underground.

Workers who may be exposed to diesel exhaust include; operators, miners, truck drivers and vehicle maintenance workers.

What are the Health Effects of Exposure to Diesel Exhaust Fumes?

Exposure to diesel exhaust can cause both short- term (acute) and long term (chronic) health effects.

Short-term (Acute) effects

Short term exposure to high concentrations of diesel exhaust can irritate the eyes, nose, throat and lungs and cause light-headedness, coughing, phlegm and nausea.

Very high levels of diesel exhaust exposure can lead to asphyxiation from carbon monoxide poisoning.

Long-term (Chronic) effects

Long term exposure can worsen asthma and allergies and increase the risk of heart and lung disease. Diesel engine exhaust emissions contain many known carcinogenic substances, for example PAHs adhere to the surface of the DPM. DPM is easily inhaled into the respiratory tract and there is epidemiological evidence which indicates ongoing exposure to diesel exhaust emissions may result in an increase in the risk of lung cancer.

How can Diesel Exhaust Exposure be Minimised?

Use better air flow, increasing air flow is a safe way to minimise worker exposure. Diesel exhaust in enclosed areas including when engines are idling or under maintenance can be reduced using local exhaust ventilation (LEV), extraction or general ventilation including improved natural air flow.

LEV systems remove diesel exhaust before it gets into the air you breathe. Tailpipe or stack exhaust hoses can be attached to a stationary vehicle running indoors and exhausted to outside with an exhaust extraction system where it will not re-enter the workplace or contaminate other areas.

Operators must regularly monitor cabin odours/fumes and immediately report any concerns they have to their Supervisor.

If during the course of work operators encounter odours/fumes entering the cabin of the equipment being used, they must immediately shut down the equipment, remove themselves from the hazardous environment and report the event to their Supervisor for immediate investigation.

Use Safer Work Practices

All diesel engines should:

• have regular maintenance, frequent tune-ups and the exhaust system checked for leaks,

• be turned off whenever possible rather than leaving them idling, and

• be fitted with emission control devices (air cleaners) like collectors, scrubbers and ceramic particle traps—these should be checked often and replaced when dirty.

Cracks or holes in cabins of plant with diesel engines and their doors and windows should be sealed to prevent diesel exhaust from seeping in.

These should be checked regularly and repaired immediately if leaks are detected. The number of diesel-powered plant and workers in the exposure area should be reduced, where reasonably practicable. Workers should be provided with information on hazards associated with diesel exhaust and how to minimise exposure.

Consider use of appropriate PPE:

Respirators are the least effective method of minimising diesel exhaust exposure and should only be used when it is not possible to control diesel exhaust exposure in other ways.

Respiratory protective equipment (RPE) may be appropriate in some situations however you should get advice from a competent person like an occupational hygienist if you are not sure.

Specific types of respirators must be used to reduce diesel exhaust exposure. P2 disposable respirators may be suitable if the concentration of vapour in the diesel exhaust is low. Half or full-face respirators with a filter cartridge that protects against gases, organic vapours and particles are generally more suitable.

Further information is available in the Australian Standards AS/NZS 1716:2012 Respiratory Protective Devices and AS/NZS 1715:2009 Selection, Use and Maintenance of Respiratory Protective Equipment.

Some Additional Resources:

Additional Information on managing risks of diesel exhaust exposure in the workplace is available at the following sites:

The WorkPac Group Safety and Risk Team will be providing regular updates on this important topic for you.

For further information and assistance please contact your Regional Risk Manager on 1300 967 572 or ServiceCentre-OSH@Workpac.com