From WES to WEL: What Australian workplaces need to know

Australia is preparing for an important change in the way workplace exposure to airborne contaminants is regulated.

From 1 December 2026, the current Workplace Exposure Standards for Airborne Contaminants, commonly known as the WES, will be replaced by the new Workplace Exposure Limits for Airborne Contaminants, or WEL.

The transition is more than a change in terminology. While the underlying duty to protect workers remains, exposure limits for a range of substances are being updated to reflect contemporary health evidence.

Australian businesses should use the transition period to identify the contaminants present in their workplaces, review the applicable limits and confirm that their existing controls remain effective.

What are airborne contaminants?

Airborne contaminants are hazardous substances that may be released into the air during work activities. They can take the form of:

• dusts;

• fumes;

• gases;

• vapours;

• fibres;

• smoke; or

• mists.

Some airborne contaminants are easy to see or smell, but many are not. They may be generated by cutting, grinding, welding, spraying, mixing, crushing, drilling, handling chemicals or operating machinery.

Workers can be exposed when contaminants enter their breathing zone. Depending on the substance, concentration and duration of exposure, the resulting health effects can range from short-term irritation to occupational asthma, hearing damage, poisoning, cancer and occupational lung disease.

Airborne contaminant risks are particularly relevant in industries such as mining, construction, manufacturing, agriculture, utilities, laboratories, transport and maintenance. However, any workplace that uses or generates hazardous chemicals should consider whether the WEL transition applies to its activities.

What are workplace exposure standards and limits?

Workplace exposure standards establish maximum airborne concentrations for particular contaminants.

Under the model Work Health and Safety Regulations, a person conducting a business or undertaking, or PCBU, must ensure that no person at the workplace is exposed to an airborne contaminant at a concentration above the applicable exposure standard.

Until 30 November 2026, Australian workplaces must continue to comply with the current WES list. From 1 December 2026, PCBUs will need to ensure that exposure does not exceed the relevant limit in the new WEL list.

Safe Work Australia states that more than 600 substances and mixtures have an established WES or WEL. However, many hazardous substances do not have a specific numerical exposure limit. The absence of a listed limit does not remove the duty to manage the risk.

Why is the terminology changing from WES to WEL?

The term “workplace exposure standard” can be misinterpreted as a target, guideline or indication of acceptable working conditions.

The new term, “workplace exposure limit”, is intended to make it clearer that the listed concentration is a limit that must not be exceeded. The change also aligns Australia more closely with terminology used internationally.

Importantly, the name change does not create an entirely new general duty. PCBUs are already required to prevent exposure above the applicable WES and to eliminate or minimise risks from airborne contaminants so far as is reasonably practicable.

The transition does, however, provide an important opportunity to review whether existing processes, monitoring programs and controls remain appropriate.

Why are the exposure limits being reviewed?

Australia first adopted its national workplace exposure standards list in 1995. Safe Work Australia notes that, since the last comprehensive review in 2003, additional evidence has emerged about the health effects of many chemicals and the concentrations at which those effects may occur.

A review of the WES list began in 2018. Following expert assessment, stakeholder consultation and consideration by Safe Work Australia Members, WHS ministers agreed to the new WEL list and a harmonised transition date.

The updated list is intended to reflect more contemporary scientific evidence and improve the protection of workers from exposure to airborne contaminants.

What is changing under the WEL list?

The changes are not the same for every contaminant.

Depending on the substance, the transition may involve:

• a reduced or increased exposure limit;

• a change in the type of exposure limit;

• the addition or removal of an airborne contaminant;

• the merging or separation of groups of contaminants;

• a change to the name of a contaminant listing; or

• a change to an advisory notation.

Safe Work Australia has published a comparison document identifying WEL entries that will be new or changed from 1 December 2026. The comparison document is not a complete list, so workplaces should also refer to the full WES and WEL lists when reviewing their obligations.

Understanding the different types of exposure limit

Exposure limits may be expressed in different ways depending on the nature of the contaminant and the risks associated with exposure.

Time-weighted average

A time-weighted average, or TWA, generally represents the average airborne concentration of a substance over a standard working day and working week.

A worker’s exposure may vary throughout a shift, but the calculated average must remain below the applicable limit. Short-term peaks may still require separate consideration, particularly where a substance also has a short-term or peak limitation.

Short-term exposure limit

A short-term exposure limit, or STEL, applies over a shorter reference period, commonly 15 minutes.

It is intended to control brief periods of higher exposure that may cause acute health effects, irritation, narcosis or other adverse outcomes even where the full-shift average remains below the TWA.

Peak limitation

A peak limitation is a concentration that should not be exceeded at any time.

Peak limitations are generally applied to substances capable of causing rapid or immediate health effects.

Businesses should not assume that compliance with a full-shift average automatically addresses short-duration exposure. Work activities that create sudden releases, process interruptions or concentrated exposure may require task-specific monitoring and controls.

Changes to advisory notations

The WEL list also changes some of the advisory notations attached to individual contaminants.

These notations provide additional information about health risks that may not be fully addressed by controlling inhalation exposure alone.

Skin and respiratory sensitisation

The existing sensitisation notation, “SEN”, will be divided into:

• DSEN, indicating dermal or skin sensitisation; and

• RSEN, indicating respiratory sensitisation.

This distinction is intended to provide clearer information about the way a substance may sensitise a worker and the types of controls that may be required.

A sensitiser may cause an allergic response after repeated or significant exposure. Once a worker becomes sensitised, even relatively low subsequent exposures may trigger a reaction.

Ototoxicity

A new OTO notation will identify certain ototoxic substances.

Ototoxic chemicals can damage hearing or affect the function of the ear. The risk may be greater when exposure to an ototoxic substance occurs at the same time as exposure to workplace noise.

For workplaces with both chemical and noise hazards, this means the risks should not always be assessed independently. A review may need to consider the combined effect of noise exposure and particular solvents, metals or other ototoxic substances.

What is happening with non-threshold genotoxic carcinogens?

Thirty-three chemicals have been removed from the WEL list and placed in a separate category as non-threshold genotoxic carcinogens, or NTGCs.

A non-threshold carcinogen is treated as a substance for which a completely safe level of exposure cannot be reliably identified.

From 1 December 2026, these substances will not have conventional numerical workplace exposure limits. Where an NTGC is present, PCBUs must:

1. eliminate its use or generation so far as is reasonably practicable;

2. replace it with a safer alternative where reasonably practicable; or

3. minimise the risk of exposure so far as is reasonably practicable where elimination is not possible.

The removal of a numerical limit should not be interpreted as reduced regulation. It places a stronger emphasis on elimination, substitution and minimising exposure rather than treating a particular concentration as safe.

What about the nine chemicals considered separately?

Nine chemicals were initially excluded from the broader 2024 agreement while Safe Work Australia undertook further regulatory impact analysis.

These chemicals were:

• benzene;

• chlorine;

• copper;

• formaldehyde;

• hydrogen cyanide;

• hydrogen sulphide;

• nitrogen dioxide;

• respirable crystalline silica; and

• titanium dioxide.

In June 2026, Safe Work Australia announced that majority support for the proposed new levels had not been reached. As a result, the exposure levels for these nine chemicals will remain the same as their current WES levels when the WEL system begins on 1 December 2026. Further work may still be undertaken in relation to these substances.

Businesses should therefore use the final published WEL list rather than relying on earlier consultation documents or proposed limits.

Does being below the WEL mean a workplace is safe?

Not necessarily.

An exposure limit should not be treated as a dividing line between a healthy and unhealthy workplace.

People have different levels of susceptibility. A worker may experience an adverse health effect at a concentration below the published limit because of an existing health condition, previous exposure, individual sensitivity or interaction with other hazards.

Safe Work Australia advises that exposure to airborne contaminants should be kept as low as is reasonably practicable, even where measurements are below the applicable exposure limit.

This means a business should not use the WEL as a target concentration. The objective should be to eliminate exposure where reasonably practicable and otherwise reduce it through effective controls.

When is air monitoring required?

Under the model WHS Regulations, air monitoring must be carried out where:

• there is uncertainty about whether exposure exceeds the applicable standard or limit; or

• monitoring is necessary to determine whether there is a risk to health.

Personal air monitoring usually measures the contaminant concentration within a worker’s breathing zone. It can help determine the exposure associated with a particular worker, task, process, location or shift.

Monitoring should be designed and interpreted by a competent person, such as a suitably qualified occupational hygienist.

A single result may not represent every working condition. Exposure can change because of:

• production volumes;

• weather and ventilation;

• material composition;

• work location;

• equipment condition;

• worker position;

• task duration;

• maintenance activities; or

• the effectiveness of controls.

Businesses may therefore need a monitoring program rather than a one-off test.

Records should clearly identify what was measured, where and when monitoring occurred, who was involved, the method used and the conditions applying at the time.

How should airborne contaminant risks be controlled?

Airborne contaminants should be managed using the hierarchy of controls.

1. Elimination

Remove the substance or process that creates the contaminant.

For example, a business might redesign a task so cutting, grinding or spraying is no longer required.

2. Substitution

Replace the hazardous substance, material or process with a safer alternative.

This could include using a less hazardous chemical, a lower-dust product or a prefabricated material that requires less on-site processing.

3. Isolation

Separate workers from the source of exposure.

Examples include enclosed systems, restricted areas, remote operation, physical barriers and automated processes.

4. Engineering controls

Use physical measures to capture or reduce the contaminant.

These may include:

• local exhaust ventilation;

• on-tool dust extraction;

• wet cutting or suppression;

• process enclosures;

• automated dosing;

• general mechanical ventilation; or

• filtration systems.

5. Administrative controls

Administrative measures can support higher-order controls but should not be relied upon as the primary method where more effective controls are reasonably practicable.

Examples include:

• reducing the time workers spend in an exposure area;

• scheduling high-exposure activities when fewer people are present;

• establishing exclusion zones;

• introducing inspection and maintenance procedures;

• providing training and supervision; and

• using documented safe work procedures.

6. Personal protective equipment

Respiratory protective equipment may be required where exposure cannot be adequately controlled through higher-order measures.

However, respirators depend on correct selection, fit, use, cleaning, storage and maintenance. Workers must also be trained in how to use and maintain required PPE.

A respiratory protection program may need to address:

• respirator selection;

• fit testing;

• facial hair and seal integrity;

• filter selection;

• change schedules;

• cleaning and storage;

• medical suitability;

• worker training; and

• ongoing supervision.

PPE should not become a substitute for eliminating or controlling the source of the contaminant.

What should Australian workplaces do before 1 December 2026?

The transition should be treated as a structured change-management exercise rather than a simple document update.

Step 1: Identify airborne contaminants

Review the substances used, stored, handled or generated across the organisation.

Consider normal operations as well as:

• cleaning;

• shutdowns;

• maintenance;

• breakdowns;

• construction;

• waste handling;

• laboratory work; and

• contractor activities.

The review should cover contaminants generated by a process, not only products purchased by the business.

Step 2: Review safety data sheets and chemical registers

Confirm that hazardous chemical registers are current and that safety data sheets are accessible.

Safety data sheets may provide information about exposure controls and regulatory limits, but businesses should verify applicable Australian limits against the current official WES or WEL list.

Step 3: Compare the WES and WEL lists

Identify which substances used or generated by the organisation are affected by:

• revised limits;

• revised exposure-limit types;

• new or changed notations;

• altered names or groupings;

• new listings; or

• removal from the numerical WEL list.

Priority should be given to contaminants with reduced limits or changes that affect existing control strategies.

Step 4: Review existing risk assessments

Existing risk assessments should be checked against the updated information.

A review should consider:

• who may be exposed;

• how exposure occurs;

• the frequency and duration of work;

• existing monitoring results;

• potential peak exposure;

• combined exposure to multiple substances;

• interaction with noise or other hazards;

• control reliability; and

• reasonably foreseeable abnormal conditions.

Step 5: Evaluate the effectiveness of controls

A control should not be assumed effective merely because it is documented.

Businesses should verify whether controls are:

• installed correctly;

• available when required;

• used consistently;

• inspected and maintained;

• capable of achieving the necessary exposure reduction; and

• supported by appropriate training and supervision.

Where a WEL is reduced, controls that previously achieved compliance may no longer be sufficient.

Step 6: Determine whether further air monitoring is required

A competent person should help determine whether additional monitoring is needed.

Further monitoring may be appropriate where:

• the exposure level is unknown;

• a limit is decreasing;

• work processes have changed;

• existing results are old or unrepresentative;

• workers report symptoms;

• controls have changed;

• there is significant variation between tasks or shifts; or

• the effectiveness of a control needs to be verified.

Step 7: Review health-monitoring obligations

Some hazardous chemicals have specific health-monitoring requirements under WHS laws.

Businesses should confirm whether workers using, handling, generating or storing relevant substances require health monitoring and ensure that the arrangements meet the requirements applying in their jurisdiction.

Air monitoring and health monitoring are different activities. Air monitoring measures contaminants in the work environment, while health monitoring assesses whether exposure may be affecting a worker’s health.

Step 8: Consult workers

Workers and health and safety representatives often have detailed knowledge of where and when exposure occurs.

Consultation should take place when identifying hazards, assessing risks, selecting controls and proposing workplace changes that may affect health and safety.

Workers should also understand:

• what contaminants are present;

• how exposure can occur;

• what controls must be used;

• how to report faults or concerns;

• what monitoring is being performed; and

• what the results mean.

Step 9: Update procedures, training and documentation

Relevant documents may include:

• hazardous chemical registers;

• risk assessments;

• safe work method statements;

• standard operating procedures;

• respiratory protection programs;

• inspection schedules;

• maintenance procedures;

• emergency plans;

• training materials; and

• contractor requirements.

Document updates should be communicated to affected workers rather than simply uploaded to a central folder.

Step 10: Establish an ongoing review process

Compliance should not end once the new limits take effect.

Businesses should review airborne contaminant risks when:

• new substances are introduced;

• materials or suppliers change;

• production increases;

• processes or equipment are modified;

• monitoring indicates increased exposure;

• controls fail;

• workers raise concerns;

• health information changes; or

• regulatory requirements are updated.

How digital HSE systems can support the transition

Managing the WES-to-WEL transition may involve information held across chemical registers, risk assessments, monitoring reports, inspections, training records and action lists.

A centralised HSE system can help organisations:

• maintain an accurate hazardous chemical register;

• link contaminants to relevant sites, activities and workers;

• record exposure assessments and monitoring results;

• assign actions arising from identified gaps;

• schedule inspections and control verifications;

• track corrective actions to completion;

• retain supporting documents and evidence;

• issue reminders for recurring monitoring or reviews;

• record consultation and training; and

• provide managers with visibility of outstanding risks.

Technology does not replace occupational hygiene expertise or effective workplace controls. It can, however, make it easier to demonstrate that exposure risks have been identified, assessed, controlled and regularly reviewed.

Preparing early will reduce disruption

The WEL transition takes effect on 1 December 2026, but organisations should not wait until the deadline to begin reviewing their arrangements.

Some businesses may need time to engage an occupational hygienist, conduct representative air monitoring, redesign a process, purchase extraction equipment, update respiratory protection programs or consult affected workers.

Starting early allows organisations to prioritise the most significant exposures and implement changes in a planned way.

The central message is straightforward: exposure limits are maximum levels, not safety targets. Whether a contaminant has a new limit, an unchanged limit or no numerical limit at all, PCBUs must continue to eliminate or minimise the risk of exposure so far as is reasonably practicable.

By reviewing contaminants, controls and monitoring arrangements now, Australian workplaces can approach the WES-to-WEL transition with greater confidence—and provide stronger protection for workers over the long term.

This article provides general information only and does not constitute legal or occupational hygiene advice. Businesses should consult the official WES and WEL lists, seek competent professional advice where required and confirm the requirements applying through their Commonwealth, state, territory or mining regulator.

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