What is changing

From 1 December 2026, the WEL for diesel particulate matter (DPM) is 0.01 mg/m³ (8-hour time-weighted average).

Employers must make sure no person at the workplace is exposed to DPM above that limit. This is a legal requirement.

Why it matters

Diesel emissions can cause serious health harm, including lung disease and cancer. You need to know where exposure comes from and control it.

What it means for your business

•    Diesel plant and equipment must be risk assessed. Controls follow the hierarchy of control. Record your decisions.

•    Baseline DPM monitoring is needed for moderate to high risk workplaces.

•    Ongoing personal monitoring may be needed for high-risk workers or work areas.

•    Upgrades and monitoring will cost money. Employees, suppliers and the company are all affected.

Controls to consider

Start at the top of the hierarchy. Respiratory protection is the last resort.

•    Replace diesel plant with electric or LPG. Use lower-emission fuel.

•    Fit DPM filtration. Improve engine combustion.

•    Use sealed cabins with HEPA-filtered air. Add local exhaust or positive pressure ventilation in workshops.

•    Keep workshop doors closed. Switch engines off instead of idling. Rotate jobs to cut exposure time.

Next step: what you need to complete

Complete these as part of your DPM assessment before 1 December 2026.

1.   List every diesel-powered plant item and DPM source on site.

2.   Engage a specialist, such as an occupational hygienist, to run baseline monitoring against the new WEL.

3.   Risk assess each source, select controls using the hierarchy of control and keep the records.

4.   Log actions in your improvement register and track them to completion.

Source: Safe Work Australia, Guide to managing risks of exposure to diesel engine emissions in the workplace.