From 1 December 2026, Safe Work Australia (SWA) is replacing the current Workplace Exposure Standards (WES) list with the Workplace Exposure Limits (WEL) list.
Airborne contaminants
Work processes can release dusts, gases, fumes, vapours and mists into the air. They are called airborne contaminants, and exposure can be harmful to health. Many of these may not be visible to the naked eye.
Employees exposed to airborne contaminants at work may be at risk of adverse health effects ranging from immediate discomfort such as eye and throat irritation to respiratory disease and even cancer.
Monitoring contaminants
PCBUs are responsible for ensuring that workers are not exposed to contaminants above the workplace exposure standards. This standard relates to a particular chemical or substance within a worker's breathing zone that could cause dangerous health effects or undue discomfort.
Workplace exposure standards (WES) list
The changes to limits are a result of evidence that has emerged since the last comprehensive review in 2003. Health-based recommendations were made by experts and released for public feedback. Safe Work Australia received more than 1,100 submissions to the review to inform the new limits.
Information in this hub can help you understand more about airborne contaminants, how to manage them, and changes to workplace exposure standards.
Workplace exposure limits (WEL) list
From 1 December 2026, Safe Work Australia will replace the WES list with the Workplace exposure limits for airborne contaminants (WEL) list. The WEL list will operate nationally. This change will make it clear there are limits which should not be exceeded and align Australia with language used internationally.
Until 1 December 2026, employers must still comply with the WES list.
You can visit Safe Work Australia’s website for information about the WEL list.
Exposure standards/exposure limits
There are three types of exposure standards:
The 8-hour TWA is the average amount of an airborne contaminant calculated over an 8-hour work day, based on a 40-hour week. A worker must not be exposed to a level above the TWA over the course of an 8-hour working day. The 8-hour TWA limit aims to protect most workers from adverse health effects of exposure to airborne contaminants.
A 15-minute STEL is the time weighted average maximum concentration of an airborne contaminant over 15 minutes. It aims to protect most workers from acute effects of exposure such as irritation, dizziness, or nausea, after short exposure.
STELs are used when brief exposure can be harmful and when there is a way to measure it.
A peak limitation is a maximum or peak concentration that must not be exceeded at any time.
Exposure above the peak limitation can cause immediate and severe health effects, even if the exposure is very short.
A peak limitation cannot be adjusted for longer or shorter working days.
Some hazardous substances have more than one type of exposure standard.
Removal of workplace exposure limits for non-threshold genotoxic carcinogens
During the development of the Workplace exposure limits for airborne contaminants (WEL list), some airborne contaminants were identified as non-threshold genotoxic carcinogens (NTGCs). Exposure to these chemicals can cause genetic damage and may lead to cancer.
Unlike other airborne contaminants, a practical, protective exposure level cannot be assigned for NTGCs due to limited data and the nature of their effects. Therefore, exposure limits have not been specified in the WEL list for chemicals identified as NTGCs.
These chemicals pose a significant risk to workers. Persons conducting a business or undertaking (PCBUs) must eliminate risks from NTGCs so far as is reasonably practicable. If elimination is not reasonably practicable, PCBUs must use the hierarchy of control measures to minimise those risks so far as is reasonably practicable. This includes, where possible:
- substituting for less hazardous chemicals, or
- isolating workers and others from exposure to NTGCs.
If neither of these are reasonably practicable, PCBUs must use engineering controls to minimise exposure. Remaining risks should be minimised using administrative controls and personal protective equipment.
There is no requirement to conduct air monitoring for NTGCs; however, a PCBU may conduct air monitoring to ensure that control measures are effective at minimising exposure to NTGCs so far as is reasonably practicable.
NTGCs are included in Appendix B of the Workplace exposure limits for airborne contaminants.
Further links:
Chemicals exempt from the WELS list
This Decision Regulation Impact Statement (Decision RIS) analysed the benefits and costs of moving to lower workplace exposure levels for nine chemicals.
The nine chemicals are benzene, chlorine, copper, formaldehyde, hydrogen cyanide, hydrogen sulphide, nitrogen dioxide, respirable crystalline silica and titanium dioxide.
The Decision RIS was prepared at the request of Work Health and Safety (WHS) ministers. The Office of Impact Analysis assessed the Decision RIS as compliant with the Regulatory Impact Analysis Guide for Ministers’ Meetings and National Standard Setting Bodies (June 2023).
The majority of WHS ministers have responded to the Decision RIS. A majority in support of new workplace exposure levels for the nine chemicals has not been reached and a majority of ministers have requested further work. There will be no changes to the exposure limits for the nine chemicals from 1 December 2026.
The workplace exposure levels for the 9 chemicals in the Decision RIS will remain the same as their current workplace exposure standards (WES) levels when Australia transitions to the workplace exposure limits for airborne contaminants (WEL) list on 1 December 2026.
Further links:
Changes to Workplace Exposure Limits - Safe Work Australia
