Australia's New Workplace Exposure Limits: What Changes on 1 December 2026 — and What It Means for Your Confined Space Gas Monitors
A significant change to Australian workplace health and safety legislation is coming, and if your business involves work in or around confined spaces, you need to act before 1 December 2026.
From that date, Australia's longstanding Workplace Exposure Standards (WES) will be replaced by the new Workplace Exposure Limits (WEL). This is not just a name change — for many gases commonly encountered in confined spaces, the permitted exposure values are changing too, and your gas monitor alarm setpoints may need to be updated to remain compliant.
Here's what you need to know.
What Is Changing, and Why?
Australia first adopted its Workplace Exposure Standards for airborne contaminants in 1995. The last comprehensive review was completed in 2003 — over two decades ago. Since then, health science and occupational medicine have advanced substantially, and the evidence around harmful exposure thresholds for many chemicals has been updated significantly.
Following an extensive review that assessed over 700 chemicals, Work Health and Safety (WHS) Ministers across Australia agreed to adopt a revised list with a national implementation date of 1 December 2026.
The terminology shift from Workplace Exposure Standards to Workplace Exposure Limits is deliberate. As Safe Work Australia has stated, the new name is designed to make clear that these are hard limits that must not be exceeded — not benchmarks or guidelines open to interpretation. The change also aligns Australia with the language used in the United Kingdom, Europe, and other international jurisdictions.
For many of airborne contaminants, the new WELs are lower than the current WES values, meaning tighter controls will be required. The most significant reductions affect gases, dusts, and fumes regularly encountered across industrial workplaces — and in confined spaces in particular.
Key Gas Changes Relevant to Confined Space Entry
Confined space gas monitors are typically configured to alarm at specific setpoints for toxic gases, oxygen levels, and flammable gases. The following changes under the new WEL are directly relevant to standard confined space atmospheric monitoring.
Carbon Monoxide (CO)
Carbon monoxide is one of the most prevalent hazards in confined spaces, generated by combustion equipment, vehicle exhaust, and biological decomposition. Under the current WES, the 8-hour Time Weighted Average (TWA) for CO is 30 ppm. Under the new WEL, this is being reduced to 20 ppm.
This is a one-third reduction in the permitted average exposure. Many sites currently set their CO low alarm at or around the WES TWA value of 30 ppm. If your monitor is configured this way, that alarm setpoint will need to be reviewed and adjusted to reflect the tighter 20 ppm limit.
Hydrogen Sulphide (H₂S)
H₂S is the most prevalent toxic gas in wastewater infrastructure, pits, tanks, and organic-matter environments — exactly the types of confined spaces that workers enter regularly. Currently, the Australian WES for H₂S sits at a TWA of 10 ppm and a STEL of 15 ppm.
These values are already higher than most international counterparts. Most comparable jurisdictions regulate H₂S to a TWA of 5 ppm and a STEL of 10 ppm. Safe Work Australia's draft WEL review considered a significant further reduction to a TWA of 1 ppm and a STEL of 5 ppm, based on guidance from the American Conference of Governmental Industrial Hygienists (ACGIH).
H₂S is subject to an ongoing Regulatory Impact Assessment, and the final adopted values will be confirmed ahead of the December 2026 implementation date. Regardless of the final outcome, a significant tightening of the H₂S limit is anticipated. Organisations operating in wastewater, water utilities, agriculture, petrochemical, and any industry where H₂S exposure is a risk should be monitoring this development closely and preparing for the need to reset their gas monitor alarm thresholds accordingly.
Nitrogen Dioxide (NO₂)
NO₂ is generated by combustion and is a hazard in poorly ventilated confined spaces where diesel-powered equipment is operated. The WEL review has considered a reduction in the NO₂ STEL, and finalised values should be confirmed ahead of December 2026. Sites running diesel equipment inside or adjacent to confined spaces should check the final WEL list and review their monitor configurations.
Welding Fumes
While not a gas-monitor parameter in the traditional sense, the TWA for welding fumes (not otherwise classified) has already been reduced from 5 mg/m³ to 1 mg/m³ with effect from January 2024. Confined spaces where welding or hot work occurs are subject to this already-in-force change.
Why Confined Space Gas Monitor Alarm Settings Matter So Much
In confined space entry, a gas monitor is not a passive compliance tool — it is the primary warning system between a worker and a life-threatening atmosphere.
Alarm setpoints on portable and fixed gas monitors are typically configured as:
• Low alarm (Action Level / TWA alarm): triggers when gas concentration approaches the occupational exposure threshold, prompting assessment and action
• High alarm (STEL or evacuation threshold): triggers immediate evacuation or cessation of entry
When the WEL reduces the TWA for a gas like CO from 30 ppm to 20 ppm, a monitor still set to alarm at 30 ppm is no longer functioning as a compliant early-warning system. Workers could be accumulating exposure above the new legal limit without any alarm activating. This represents both a health risk and a compliance failure under WHS legislation.
It is also important to recognise that alarm setpoints cannot simply be read off the WEL list and applied directly. Effective alarm configuration requires consideration of:
• The specific task and duration of confined space entry
• Potential for short-duration peak exposures versus sustained TWA exposures
• The type of atmosphere (oxygen deficiency, flammable gas, multi-gas hazards)
• The sensitivity and response time of the specific detector technology
• Any site-specific risk factors, co-exposures, or worker health considerations
Simply changing a number on a monitor without a documented risk assessment and engineering rationale is not best practice — and will not stand up to scrutiny in the event of a regulatory audit or workplace incident.
What You Need to Do Before 1 December 2026
The transition period ends on 30 November 2026. Between now and then, PCBUs must continue to comply with the current WES. However, the time to prepare is now — not in October.
Here is a practical checklist for organisations conducting confined space entry:
1. Review the WEL list and identify every airborne contaminant your workers may encounter in confined spaces
2. Compare current WES values with the new WEL values for those substances — particularly CO, H₂S, NO₂, and any site-specific contaminants
3. Audit your gas monitor alarm configurations across all portable and fixed monitoring equipment
4. Review and update your confined space permits to reference the new WEL values and any revised alarm thresholds
5. Update your confined space procedures and safe work method statements to reflect the new limits and any changes to entry conditions
6. Train your workers and supervisors on the changes and their responsibilities under the new WEL
7. Document your review and decision-making process as part of your WHS management system
How Vital Safety Can Help
At Vital Safety, we specialise in exactly this kind of work. Our team has deep experience in confined space safety, atmospheric monitoring, and WHS compliance across a wide range of industries including water and wastewater, resources, manufacturing, mining, infrastructure, and utilities.
As the 1 December 2026 deadline approaches, we are offering tailored transition support to help your organisation get ahead of the changes. Our services include:
• WEL Compliance Reviews — we'll assess your current gas monitoring equipment and alarm configurations against the incoming WEL requirements and identify any gaps
• Gas Monitor Alarm Setpoint Review and Configuration — we'll work with your team to calculate and document compliant, risk-based alarm setpoints for your specific confined space environments
• Confined Space Permit Review and Update — we'll review your entry permits, risk assessments, and atmospheric monitoring requirements to ensure they reflect the new WEL values
• Procedure and SWMS Updates — we'll update your confined space procedures, safe work method statements, and emergency response plans to align with the new legislative requirements
• Training and Awareness — we can deliver toolbox talks and formal training sessions to ensure your workers and supervisors understand the changes and their obligations
Don't wait until the deadline is weeks away. Updating alarm setpoints, rewriting permits, and training your people takes time — and the cost of non-compliance, or worse, a serious workplace incident, is far greater.
Contact the Vital Safety team today to discuss how we can support your WEL transition.
This blog is for general informational purposes only and does not constitute legal or safety advice. Always consult the current Safe Work Australia WEL list and your relevant state or territory WHS regulator for obligations applicable to your specific workplace.