WES to WEL: What Employers Need to Know

Australia is approaching a major shift in how hazardous airborne contaminants are regulated in workplaces. On 1 December 2026, Workplace Exposure Standards (WES) will transition to Workplace Exposure Limits (WEL), reflecting an increased regulatory emphasis on enforceable limits rather than advisory guidelines. To help employers understand what the change means in practice, Phoenix Occupational Medicine spoke with three experienced Occupational Hygienists from Red OHMS Group — Julie Sullivan, Micheal Lewis and Haysam Elhassan — whose insights shed light on the intent, challenges and opportunities associated with the WEL transition and the future of workplace exposure risks.

Information provided is general only and should not be construed as legal or medical advice. We recommend that readers seek advice for their specific circumstances.

What’s Behind the Change from Workplace Exposure Standards to Workplace Exposure Limits?

The shift from Workplace Exposure Standards to Workplace Exposure Limits signals a substantial regulatory pivot. While WES historically served as recommended benchmarks, WEL formally establishes airborne contaminant concentrations that must not be exceeded under law. This distinction matters. As Julie Sullivan, Certified Industrial Hygienist, explained, the change in terminology is intended to reinforce the fact that these limits are enforceable.

“By calling the airborne concentrations that are not to be exceeded ‘Workplace Exposure Limits’, instead of ‘Workplace Exposure Standards’, the aim is to highlight that they are enforceable limits, not simply guidelines,” she said.

Although the name is changing, the fundamental responsibility of employers and Persons Conducting a Business or Undertaking (PCBUs) remains the same: to identify, assess and control risks associated with hazardous substances in the workplace. The new limits will shape how organisations demonstrate compliance and ensure their controls are sufficiently protective.

WEL also introduces updated scientific understanding into national regulation. Employers requiring further context can refer to occupational hygienists for insight into hygiene sampling and exposure evaluation practices, and to Safe Work Australia for detailed transition guidance.

Key Changes Employers Need to Prepare For

While many airborne contaminant limits have been revised downwards, the extent of change varies between substances. Julie noted that the long-term trend of lowering exposure limits is well established. “This trend of lowering exposure levels is nothing new. When you consider that the exposure limit for asbestos in the 1960s was 50 f/cc, compared to 0.1 f/cc now.”

Several changes stand out:

Thirty-one new airborne contaminants have been added to the regulated list, including diesel particulate matter and flour dust. Others have been removed altogether as they are no longer legally permitted for import, manufacture or use, such as DDT.

Welding fumes will now require assessment of both inhalable and respirable fractions, increasing the complexity of exposure evaluation.

Hydrogen sulphide has been significantly reduced to one-tenth of the current standard, presenting challenges for wastewater treatment and similar operations.

WEL includes a category of Non-Threshold Genotoxic Carcinogens (NTGC), substances for which no safe exposure level is identifiable.

From a compliance perspective, the most important shift is the fact that WEL will be enforceable under WHS legislation. Organisations will need to ensure controls are capable of maintaining exposures within the revised limits and that monitoring is adequate to demonstrate compliance.

Why the Change Matters

According to Certified Occupational Hygienist Haysam Elhassan, the move to WEL is the outcome of an extensive review of workplace exposure science. “Since the last major review in 2003, there’s been a lot of new evidence and research into the health risks associated with certain chemicals. In some cases, it has been determined that certain chemicals are not safe at all – such as the non-threshold genotoxic carcinogens.”

The WEL framework also aligns Australia more closely with international standards, ensuring that regulation keeps pace with global research and best practice. While some substances such as Respirable Crystalline Silica have already undergone earlier revision, the broader alignment achieved through WEL represents the most comprehensive update in over two decades.

Julie highlighted that although industry has been given a transition period, the intent is clear: employers must begin preparing well before December 2026.

What the New Limits Mean for Today’s Workforce

Historically, Workplace Exposure Standards were developed around a model worker: a 40-year-old male whose working life spanned an average of 40 years. This assumption no longer represents the diversity of Australia’s workforce. WEL has been developed for workers across a wider age range and includes consideration of both male and female sensitivities and variations in underlying health.

“What you need to remember is that these are not strict safe / not safe zones,” Julie clarified. “The WEL are based on the desired outcome that a worker – not wearing a respirator – could work 8 hours a day, 5 days a week for their whole work life, without developing an occupational disease or adverse health effects.”

This broader consideration means WEL aims to protect workers across their entire working lifespan, regardless of age, role, or sex, reinforcing the importance of robust exposure control and workplace design.

Understanding Exposure – ‘Not a Magic Number’

Despite the formalisation of exposure limits, Micheal Lewis emphasised that these values should not be misinterpreted as absolute thresholds. “Unfortunately, there is still too much focus on standards or levels as being a magic number.”

He explained that exposure assessment is multidimensional and cannot be reduced to a simple safe/unsafe binary. “Industry often sees these levels as safe/unsafe or go/no-go, but it’s never a zero risk. That’s where the expertise of your occupational hygienist comes in.”

3 Factors Occupational Hygienists Use to Assess Exposure

Concentration of the exposure

Duration of exposure

Frequency of exposure

Micheal added that understanding physiology is crucial. Exposures are influenced not only by how long workers are exposed but also by the “recovery time” between exposures. He noted that most current exposure standards assume an eight-hour day and 40-hour week. Longer shifts or compressed rosters change how the body processes exposures.

“It could be that the 16 hours away from the exposure gives a person’s body and systems a chance to process and recover. So, it follows that if this recovery time is shortened for some people, this needs to be factored into your overall management plan.”

For example, in a roster involving 12-hour shifts or a 13-day fortnight, exposure controls may need to be more stringent to achieve the same level of protection. As Micheal said, “If your team is on a 13-day fortnight or a 12-hour shift, then that 10 ppm level won’t cut it.”

The Human Factor – An Occupational Medicine Perspective

Dr Sid O’Toole, Occupational and Environmental Physician, reflected on the complexity underlying exposure effects. “What Michael is saying above really identifies the complexities in determining the effects of exposures. All chemicals or exposures only start to demonstrate a change in an exposed person when they reach a level beyond the body’s capacity to handle it.”

He noted that dose–response relationships vary widely. “All substances do actually follow a dose response curve, but the line is not always straight, and can vary between individuals and even in the same individual at different times, depending on their underlying health.”

This variability is one reason why Occupational and Environmental Physicians are essential in managing workplace health. They are trained to interpret not only exposure data but the full clinical picture: why one worker may show early signs of impairment while another does not, how underlying health conditions may influence susceptibility, and what safe return-to-work looks like for each individual.

Dr O’Toole emphasised the importance of collaboration. “Working together, Occupational Hygienists and Occupational Physicians bring certainty and health security to the workforce in a continuum of hazard and risk identification, measurement, analysis and health determinations.”

For organisations seeking integrated medical oversight, Phoenix Occupational Medicine provides specialist health surveillance and workplace assessment services to support compliance and worker wellbeing.

Which Industries Will Feel It Most?

While all industries must comply with the new workplace exposure limits, some will face more significant challenges due to the nature of their operations. These include:

Construction and demolition, particularly due to exposure to respirable crystalline silica

Mining and quarrying, where diesel exhaust and mineral dusts are prevalent

Manufacturing and fabrication, where welding fumes are widespread

Local government and waste management services, particularly in wastewater operations

Water treatment environments where hydrogen sulphide levels may now exceed the dramatically reduced WEL

Smaller regional councils may be especially affected where access to advanced monitoring technology or engineering controls is limited. Certain sampling requirements may exceed the capabilities of existing technology, though Julie noted that laboratories and equipment manufacturers are evolving quickly to meet industry needs.

Monitoring and Compliance – The Role of Occupational Hygienists

Occupational Hygienists play an integral role in helping organisations understand how WEL applies to their workplace. Micheal explained that hygiene assessment is not simply technical: “There are hundreds of ways to quantify a risk. It’s important to understand why the assessment is taking place.”

Julie added that initial conversations and site walkthroughs are essential to shaping effective monitoring. Techniques may include air monitoring, real-time video dust monitoring, ventilation assessment and, where appropriate, statistical analysis.

Haysam shared a practical example from an asphalt resurfacing project where workers were exposed to respirable crystalline silica during jackhammering. Water spray was used for dust suppression, but real-time monitoring revealed that the droplets were too large to capture the respirable fraction effectively. A new on-tool misting system was introduced as a result.

Monitoring is Part of a Feedback Loop

Monitoring should not be a one-off exercise. Micheal recommended annual monitoring when exposures are below 50 per cent of the WES/WEL, with reassessment required whenever processes, equipment or materials change.

Preparing for the 2026 Deadline

With the transition date approaching, Julie recommended several priority actions for organisations:

Identify high-risk substances in your operations.
Conduct initial air monitoring.
Update risk assessments.
Implement basic controls such as ventilation and substitution.
Train staff and document all actions.

These steps form the foundation for compliance as the new workplace exposure limits come into effect.For organisations seeking clarity on exposure risks, medical impacts or occupational health requirements, contact Phoenix Occupational Medicine to discuss tailored support.

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Key Takeaways

Workplace Exposure Limits will become enforceable under WHS law on 1 December 2026.

Most limits are being reduced, and new contaminants are being added.

Exposure management requires more than meeting a number; it demands understanding concentration, duration and physiological recovery.

Collaboration between Occupational Hygienists and Occupational and Environmental Physicians provides a holistic approach to worker health and regulatory compliance.