Preparing for the WEL: Common gases with decreased exposure limits

Transitioning from WES to WEL

On 1 December 2026, the Workplace Exposure Limits for Airborne Contaminants (WEL) will officially commence, replacing the Workplace Exposure Standards (WES). This means that businesses should ensure they are compliant with WEL before that date.

The WEL isn’t just a change of name, it has introduced new notation for ototoxic chemicals, made new rules for non-threshold genotoxic carcinogens, and notably decreased the exposure limit for a wide range of gases common across many Australian workplaces and more.

This article will focus on some of these common gases that will have lower exposure limits. It’s an important topic because transitioning to become compliant with stricter limits is not just a matter of lowering alarm levels, it involves a holistic assessment of gas monitoring and detection programs. Audit, stocktake and service of gas detection instrumentation to ensure compliance with the limits, and most importantly, ensure worker safety, takes time and expertise. With the commencement of WEL less than 2 months away, now is the time to act.

Air-Met Scientific offers a wide range of service capabilities including on site assessment of gas alarm systems and gas detection programs. Get ready for the upcoming WES to WEL transition by getting in touch with you local office today.

Common gases with reduced exposure limits

The following table highlights eleven gases commonly found in Australian workplaces, showing the old limit, new limit and common exposure environments and applications. This list is non-exhaustive. PCBUs should check the entire WEL to ensure they are compliant with any new limits by 1 December 2026.

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Preparing for WEL: It’s time for monitoring and detection review, stocktake and audit

Looking at the table above, it’s clear that the changes aren’t as simple as they might seem. A substance like hydrogen chloride previously just had a peak limitation, now not only has the peak limitation been reduced but a TWA has been introduced. These complexities illustrate the importance of holistic review of monitoring and detection systems. Again, preparation requires more than just lowering alarm thresholds.

This is why it is so important to engage occupational hygienists who have the experience and expertise required to determine the safest, most effective, and most efficient gas detection program.

There is no one-size-fits-all approach to gas detection. A range of types of gas monitoring and detection equipment exist that all serve a specific purpose. With the upcoming commencement of the WEL list, now is the perfect time for businesses to review their gas detection program including conducting a stocktake and audit of existing systems. It is also expected that most businesses may need to significantly adjust alarm settings on gas detectors given the number of common gases which have had their limits decreased or exposure limit measurements changed.

Comprehensive gas detection programs use a suitable combination of instrumentation as each type of instrument serves a distinct purpose.

Fixed Gas Detection

Fixed gas detection is an essential aspect of a gas detection system in workplaces where it is known exposure to certain hazardous gases is likely. Fixed systems monitor gas concentrations in a specific area. For example, in industrial refrigeration where ammonia is used as a coolant, the AIYI Technologies AG310 may be permanently installed as constant monitoring is required to protect both people and assets from the dangers of any potential gas leaks. Due to the importance of maintaining fixed gas detection systems, expert service is needed to make sure that the system is compliant and configured correctly.

Personal Gas Detection

As the name suggests, personal gas detection is to measure when an individual’s exposure to certain gases exceeds certain a safe threshold. Personal gas detectors such as the Industrial Scientific Ventis Pro 5 are worn by a worker as they perform their work duties and are generally capable of measuring the concentration of multiple gases at once. This kind of gas detection is especially important for applications which involve entry into confined spaces that are only intermittently accessed by personnel where gas buildup can occur.

Air Sampling for Gases

Air sampling for contaminants is an important component for the assessment of compliance with exposure limits. Personal air sampling involves appropriate method selection, media selection and use of body worn continuous air sampling pumps such as the SKC Essential+ or Pocket Pump Touch for low flow sampling to collect a sample of certain airborne contaminants that a worker is exposed to. The sample media is then sent to a lab an analysed. This is an important step in compliance as it can identify what substances a worker is exposed to and provides an accurate assessment of the level of exposure over a given time period which makes it particularly useful for assessing time-weighted average exposures, exposure to specific volatile organic compounds, and contaminants which are difficult to measure with direct reading instruments.

Passive Sampling Badges

Passive sampling badges are another option for personal air sampling. SKC provides samplers for a range of gases such as sulphur dioxide, volatile organic compounds (VOCs), ammonia and formaldehyde. Passive samplers do not require an air sampling pump and are worn by the worker as they go about their work, collecting a sample that can be sent to a lab for analysis. While they aren’t suitable for measuring STEL, passive samplers provide a convenient, inexpensive and simple way to obtain data for TWA exposure measurements.