Australia is transitioning from workplace exposure standards (WES) to workplace exposure limits (WEL), with the new values taking effect on 1 December 2026. The WES values, published by Safe Work Australia, have been the benchmark for atmospheric contaminant exposure in Australian workplaces for decades. The WEL values represent a comprehensive update based on current toxicological evidence and align more closely with international best practice. For many substances, the new WEL values are significantly lower than the current WES values, meaning PCBUs will need to implement additional controls to achieve compliance. Understanding the differences between the two systems is essential for every PCBU that manages chemical exposure in the workplace.
| Aspect | WES (Workplace Exposure Standards) | WEL (Workplace Exposure Limits) |
|---|---|---|
| Legal Status | Currently enforceable under WHS Regulation | Enforceable from 1 December 2026 under WHS Regulation 2025 |
| Scientific Basis | Based on historical toxicological data, some decades old | Based on current international toxicological evidence |
| Number of Substances | Approximately 700 substances listed | Over 50 substances with changed values in initial tranche |
| Typical Direction | Higher permissible concentrations for many substances | Lower permissible concentrations reflecting updated health evidence |
| Monitoring Approach | 8-hour TWA and 15-minute STEL as primary metrics | 8-hour TWA and 15-minute STEL retained, with additional assessment guidance |
| Health Surveillance | Triggered by exposure at or above the WES value | Triggered by exposure at or above the WEL value, with lower thresholds for many substances |
| Compliance Cost | Current controls and monitoring programs designed for WES values | Many PCBUs will require upgraded engineering controls and monitoring equipment |
| International Alignment | Diverges from many international standards | Closer alignment with UK, EU, and other international exposure limits |
WES values remain the enforceable standard until 1 December 2026. PCBUs must continue to comply with WES values during the transition period. However, PCBUs should not wait until the transition date to begin planning for the new WEL values. Where the new WEL for a substance is significantly lower than the current WES, the PCBU should begin assessing current exposure levels against the future WEL now. This allows time to design, procure, and install engineering controls such as upgraded local exhaust ventilation, enclosed processes, or substituted materials before the compliance deadline.
From 1 December 2026, all PCBUs must comply with the WEL values. PCBUs that currently monitor atmospheric contaminants must recalibrate their monitoring programs against the new values, review all risk assessments that reference exposure standards, update their chemical registers and safety data sheet references, and assess whether current controls are adequate to maintain exposures below the new limits. PCBUs in industries with high chemical exposure, including manufacturing, mining, construction, and laboratory work, should begin transition planning immediately.
During the transition period before 1 December 2026, PCBUs must comply with the current WES values as the legal minimum. However, best practice is to begin working towards the WEL values now, particularly for substances where the WEL is substantially lower than the WES. This dual-reference approach allows the PCBU to prioritise capital investment in engineering controls for the substances with the greatest gap between current and future limits. After 1 December 2026, only the WEL values apply and WES values are superseded entirely.
Many PCBUs assume that the WEL transition only affects a small number of substances and that their current controls will be adequate. In practice, the WEL values for common workplace substances such as welding fume, wood dust, and several solvents are significantly lower than the current WES values. A PCBU that is currently compliant with the WES may find that the same exposure level exceeds the new WEL by a substantial margin. The transition requires active assessment and planning, not passive waiting for the deadline.
EHS Atlas provides WES-to-WEL gap analysis, substance-specific impact assessment, and transition planning tools to ensure your workplace is compliant before 1 December 2026.
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