Workplace Exposure Limits: What Changes in December 2026

Australia is replacing its current Workplace Exposure Standards (WES) with new Workplace Exposure Limits (WEL) from 1 December 2026. This is the most significant change to occupational exposure regulation in over two decades. The current WES values are largely based on American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values from the 1990s and 2000s. Many are now recognised as insufficiently protective based on contemporary epidemiological and toxicological evidence.

The new WELs are based on Safe Work Australia's multi-year review of international evidence, drawing on exposure limits from the United Kingdom, Germany, the European Union, and updated ACGIH values. For many substances, the new WEL is significantly lower than the current WES — reductions of 50 to 99 per cent are common. This means workplaces that are currently compliant with the WES may be non-compliant with the new WEL from day one of the transition. Businesses have until 1 December 2026 to prepare, but given the lead times for engineering controls, ventilation upgrades, and process changes, preparation should be well underway.

Several high-profile substances are subject to dramatic reductions in their permissible exposure concentration. Manganese (inhalable fraction) drops from 1 mg/m3 to 0.02 mg/m3 — a 98 per cent reduction that affects welding, steel manufacturing, and battery production. Nickel (inhalable fraction) drops from 1 mg/m3 to 0.01 mg/m3 — a 99 per cent reduction affecting metal fabrication, stainless steel welding, and electroplating. Chromium VI (inhalable fraction) drops from 0.05 mg/m3 to 0.005 mg/m3 — a 90 per cent reduction affecting welding, chrome plating, and cement manufacturing.

Respirable crystalline silica drops from 0.05 mg/m3 to 0.025 mg/m3 — a 50 per cent reduction affecting construction, mining, stone cutting, and manufacturing. Welding fume (total) drops from 5 mg/m3 to 1 mg/m3, and this change took effect from 17 November 2025. Several substances that previously had no WES will have a WEL for the first time, including diesel particulate matter (0.1 mg/m3) and flour dust (0.5 mg/m3 inhalable). These new limits affect mining, construction, transport, and food manufacturing industries.

The WHS Regulation 2025 requires PCBUs to ensure that no worker is exposed to an airborne contaminant at a concentration exceeding the workplace exposure limit. From 1 December 2026, this obligation references the new WEL values. PCBUs should begin preparation immediately by conducting a gap analysis: compare your current exposure monitoring results against the new WELs to identify which exposure groups may exceed the new limits.

For substances where current exposures are between the new WEL and the current WES, the PCBU must implement additional controls to reduce exposure below the new limit. This may require upgrading local exhaust ventilation systems, substituting materials, changing work processes, reducing exposure duration through job rotation, or providing higher-level respiratory protective equipment as an interim measure. Commission a qualified occupational hygienist to conduct baseline exposure monitoring now so you have a clear picture of your starting position. Do not wait until November 2026 to discover that your exposures are above the new limits.

The WHS Regulation 2025 requires atmospheric monitoring when a PCBU is not certain on reasonable grounds that the concentration of an airborne contaminant does not exceed the workplace exposure limit. With lower WELs, the threshold for certainty drops — more workplaces will need to conduct formal atmospheric monitoring because the margin between typical exposures and the new limits is much narrower.

Health surveillance requirements under the WHS Regulation 2025 apply to workers exposed to specific scheduled substances and hazards. Health surveillance includes medical examinations, biological monitoring, and health questionnaires tailored to the substance of exposure. For substances with dramatically reduced WELs, such as manganese and chromium VI, health surveillance becomes even more critical because the health effects (neurological damage and lung cancer respectively) are severe and often irreversible. PCBUs must ensure health surveillance is supervised by a registered medical practitioner with experience in occupational health and that results are reported to the worker and the PCBU in accordance with privacy requirements.

The most significant practical impact of the WEL transition is on engineering controls, particularly ventilation systems. A local exhaust ventilation system designed to maintain exposures below 1 mg/m3 may not be adequate to achieve 0.02 mg/m3 for manganese. Achieving a 50-fold reduction in the permissible exposure concentration typically requires a fundamental redesign of the ventilation system, not just a filter change or duct modification.

PCBUs should commission a ventilation assessment from a qualified ventilation engineer or occupational hygienist to evaluate whether existing LEV systems can achieve capture efficiencies consistent with the new WELs. Key parameters include face velocity at the capture point, transport velocity in ductwork, air changes per hour in enclosed spaces, and filter efficiency for the particle sizes of concern. For some operations, the only reasonably practicable approach may be total enclosure with negative pressure ventilation, which fundamentally changes the work setup. Start planning now — ventilation design, procurement, and installation lead times can exceed 12 months, and the 1 December 2026 deadline will not be extended.