What is the WES → WEL transition and when does it happen?
Short answer
On 1 December 2026, Safe Work Australia's "Workplace Exposure Standards (WES)" for airborne contaminants are formally replaced by the new "Workplace Exposure Limits (WEL)". The new WELs are health-based and in many cases tighter than the WES they replace. Every PCBU exposed to airborne contaminants needs to re-baseline against the WELs.
For decades, Safe Work Australia has maintained the Workplace Exposure Standards (WES) — Time-Weighted Average and Short-Term Exposure Limit values for airborne contaminants. These were largely inherited from older NHMRC and overseas data.
From 1 December 2026, the WES framework is formally replaced by the Workplace Exposure Limits (WEL) framework. The WEL values are:
- Health-based — derived from current toxicology and epidemiology, not historical practice.
- In many cases, tighter — particularly for known carcinogens (silica, hexavalent chromium, formaldehyde, diesel particulate matter) and respiratory sensitisers.
- Aligned to international consensus — closer to NIOSH, ACGIH and EU OEL benchmarks.
For PCBUs with airborne contaminant exposure (manufacturing, mining, agriculture, construction, healthcare, hospitality), the transition means:
- Re-baseline monitoring data against the new WELs — exposures that were "acceptable" under the WES may exceed the WEL.
- Update risk assessments and chemical risk assessments to reference WELs.
- Review control measures — engineering controls, ventilation, PPE — to ensure they keep exposures below the new WEL.
- Update health monitoring programmes — particularly for silica, lead and isocyanate exposures.
RAE IQ flags WEL values in chemical risk assessments from 1 December 2026 and has the WES → WEL transition wired through the document generator.