Diesel Exhaust Has a New Workplace Exposure Limit in Australia

Transport and logistics businesses are among the workplaces where workers may be exposed to diesel engine emissions.

From 1 December 2026, diesel particulate matter (DPM) will have a new Workplace Exposure Limit (WEL) in Australia.

For freight depots, loading docks, warehouses, distribution centres and fleet workshops, the change provides a clear reason to review where diesel exhaust exposure occurs and whether existing controls are adequate.

Exposure is not limited to drivers. Loading dock workers, warehouse employees, mechanics, forklift operators and yard workers may also be exposed, particularly where diesel engines operate in enclosed or partially enclosed areas.

What does the new diesel limit mean for transport and logistics?

Australia will transition from Workplace Exposure Standards (WES) to Workplace Exposure Limits (WELs) on 1 December 2026.

As part of the change, diesel particulate matter will have a specific Workplace Exposure Limit.

This is particularly relevant to transport and logistics because diesel-powered vehicles and equipment can move through multiple areas of a workplace during a single shift.

A truck, for example, may enter a depot, idle at a loading dock, move through a yard and later enter a fleet workshop. Each activity can potentially expose different groups of workers.

The issue is therefore broader than the exposure of the driver alone.

Where can diesel exhaust exposure occur?

Transport and logistics workplaces can have multiple diesel exhaust sources. Exposure will depend on factors including the number and type of engines, how frequently they operate, ventilation, work practices and how close workers are to the source.

Workers do not need to operate diesel equipment themselves to experience exposure. Exhaust from a loading dock may enter an adjoining warehouse, while mechanics may work close to running engines during servicing and diagnostic work.

Loading docks and freight depots

Loading docks can be an important diesel exhaust exposure area because workers may be close to repeated truck movements throughout the day.

A single truck may only spend a relatively short period at a loading bay, but loading dock workers can experience repeated vehicle arrivals, departures, reversing and idling across an entire shift.

Potential exposure may be greater where loading docks are enclosed or partially enclosed and diesel exhaust cannot disperse effectively.

Factors to consider include:

• how many trucks use the loading area;
• how frequently vehicles arrive and depart;
• whether engines are left idling;
• how close workers are to vehicle exhausts;
• whether the loading area is enclosed or partially enclosed;
• the effectiveness of natural or mechanical ventilation; and
• whether exhaust can enter adjoining work areas.

Warehouses and distribution centres

Warehouses and distribution centres can have several potential sources of diesel exhaust exposure.

Diesel-powered forklifts or other plant may operate within the building, while truck exhaust can enter from adjoining loading docks, roller doors and receival areas.

Workers who spend an entire shift within these areas may experience repeated exposure even though they never operate a diesel-powered vehicle themselves.

Fleet maintenance workshops

Fleet workshops can present a different exposure profile because mechanics and maintenance workers may work close to operating diesel engines.

Exposure may occur when workers:

• start engines indoors;
• undertake diagnostic testing;
• leave engines running during repairs;
• move trucks through workshops or service bays; or
• work near multiple vehicles during a shift.

Where engines need to operate indoors, the effectiveness of ventilation and exhaust extraction becomes particularly important.

Maintenance activities may also generate other airborne contaminants through welding, cutting, grinding, painting, solvents and degreasers. An occupational hygiene assessment can consider these exposures alongside diesel engine emissions.

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Who could be exposed to diesel exhaust?

Diesel exhaust exposure in transport and logistics can extend across several roles and work areas.

How is diesel particulate matter measured?

The new diesel particulate matter Workplace Exposure Limit is expressed as respirable elemental carbon.

Personal air monitoring can be used to assess what a worker encounters within their breathing zone while carrying out normal work activities.

This is particularly useful in transport and logistics because exposure can change significantly during a shift as vehicles arrive and depart, workers move between areas and different activities take place.

An occupational hygienist may establish Similar Exposure Groups (SEGs), grouping workers who undertake comparable tasks under similar conditions rather than necessarily monitoring every employee.

In a transport and logistics operation, Similar Exposure Groups could include:

• loading dock workers;
• warehouse employees;
• forklift operators;
• fleet mechanics;
• yard workers; and
• drivers.

What should transport and logistics businesses do before 1 December 2026?

A practical starting point is to follow diesel-powered vehicles and equipment through their normal journey across the site.

1. Identify diesel sources

Map where trucks, forklifts, yard vehicles and other diesel-powered equipment operate.

2. Identify potentially exposed workers

Look beyond drivers to loading dock workers, warehouse employees, mechanics, forklift operators, yard workers and dispatch staff.

3. Review the working environment

Consider engine operating time, vehicle movements, worker locations, ventilation and whether exhaust can accumulate or travel into occupied areas.

4. Review existing controls

Consider whether current controls adequately minimise exposure and whether opportunities exist for higher-order controls.

5. Consider exposure monitoring

Where the level of exposure remains uncertain, occupational hygiene assessment and personal exposure monitoring can provide objective information about worker exposure.

6. Implement and document improvements

Use the findings to prioritise practical improvements ahead of the new Workplace Exposure Limit.

How can transport businesses reduce diesel exhaust exposure?

Businesses should eliminate exposure to diesel engine emissions where reasonably practicable. Where elimination is not reasonably practicable, exposure should be minimised so far as reasonably practicable.

The hierarchy of controls provides the framework for managing the risk.

Practical measures can include:

• replacing diesel-powered equipment with electric or other alternatives where reasonably practicable;
• switching off trucks, forklifts and other diesel engines when they do not need to run;
• reducing unnecessary vehicle idling at loading docks and depots;
• separating workers from diesel exhaust sources;
• reviewing traffic routes and vehicle movements to reduce worker exposure;
• improving natural or mechanical ventilation in enclosed and partially enclosed areas;
• using local exhaust extraction where engines need to operate indoors; and
• maintaining engines and emission-control systems.

Higher-order controls should be prioritised rather than relying solely on respiratory protective equipment where other reasonably practicable controls are available.

When should diesel exhaust monitoring be considered?

Exposure monitoring may be useful where there is uncertainty about the level of diesel particulate matter workers are exposed to.

For transport and logistics businesses, this may include workplaces where: