Frequently asked questions

Airborne contaminants may occur as vapours, dusts, particles, fibres, fumes or gases or combinations of these and can be released into the air when using hazardous chemicals or carrying out work processes. Breathing in airborne contaminants can impact health in ways that range from short-term irritation of the eyes, nose and throat to serious respiratory disease and cancer.

Learn more about airborne contaminants.

A workplace exposure limit, or WEL, is the maximum airborne concentration of a substance that most people can be exposed to without harm to their health. It is used to assess risk, choose and design controls, and check that exposures are controlled, particularly through inhalation.

From 1 December 2026, Safe Work Australia’s Workplace Exposure Limits (WEL) list will replace the Workplace Exposure Standards (WES) list and become the nationally recognised reference for airborne contaminants in the workplace.

The WEL list includes changes to exposure limits and airborne contaminant listings, including:

• 31 airborne contaminants with limits introduced for the first time
• reduced or increased exposure limits for some airborne contaminants
• 33 non-threshold genotoxic carcinogens (NTGCs) that will no longer have exposure limits
• 6 other airborne contaminants removed because their import, manufacture and use are prohibited under Australian legislation
• other changes to names, groupings, exposure-limit types and advisory notations.

More information about changes between the WES list and WEL list can be found on Safe Work Australia’s Changes between the WES and WEL webpage.

Yes, but specific arrangements apply in Queensland.

From 1 December 2026, Queensland will adopt the national WEL list with transition arrangements for 15 substances:

• bitumen fumes
• diesel particulate matter (DPM), measured as respirable elemental carbon
• flour dust
• grain dust
• hydrogen fluoride
• manganese fume, dust and compounds
• methyl bromide
• nickel metal, powder and nickel sulphide roasting
• nitric oxide
• perchloroethylene
• phosphine
• Portland cement
• styrene monomer
• sulphur dioxide
• wood dust (softwood).

For flour dust, no limit applies until 1 December 2029. For diesel particulate matter (measured as respirable elemental carbon), a time weighted average of 0.1mg/m³ applies until 1 December 2029.

For all other substances, the workplace exposure standard (WES) continues to apply until 1 December 2029.

The workplace exposure limits for airborne contaminants (WEL) list is the result of Safe Work Australia’s national review of workplace exposure standards (WES). The review considered contemporary scientific and health evidence, expert recommendations, and more than 1,100 public submissions, resulting in updated limits to better protect workers from harmful airborne contaminants.

For more information, visit the Safe Work Australia Workplace Exposure Standards Review webpage.

Proposed changes for nine chemicals that were the subject of a national decision regulation impact statement were not agreed to by a majority of WHS Ministers. Proposed exposure limits for benzene, chlorine, copper, formaldehyde, hydrogen cyanide, hydrogen sulphide, nitrogen dioxide, respirable crystalline silica and titanium dioxide will not change on 1 December 2026.

For further information, see the Safe Work Australia Decision Regulation Impact Statement: Proposed workplace exposure limits for 9 chemicals webpage.

As part of the transition to the WEL list, some carcinogens have been reclassed as non-threshold genotoxic carcinogens (NTGCs).

These substances have no prescribed WEL as there is no identified level of exposure that is considered safe.

Where the hazardous chemicals used or generated in the workplace are listed in Schedules 10 and 14 of Queensland’s Work Health and Safety Regulation 2011, you must continue to comply with your obligations in the schedules.

NTGCs pose a significant risk to worker health as they can cause genetic damage and may lead to cancer. PCBUs that use or generate NTGCs must eliminate exposure to these substances so far as is reasonably practicable. Where elimination is not reasonably practicable, PCBUs must minimise exposure by applying the hierarchy of control measures. This may include:

• substituting the substance with a less hazardous alternative
• isolating workers and others from exposure
• implementing engineering controls to minimise exposure
• using administrative controls and personal protective equipment (PPE) to manage any remaining risk.

There is no mandatory requirement to conduct air monitoring for NTGCs. However, air monitoring may be used to verify that control measures are effectively minimising exposure so far as is reasonably practicable. NTGCs are listed in Appendix B of the Workplace exposure limits for airborne contaminants.

For more information read the WES review – Non-threshold based genotoxic carcinogens.

There are three types of exposure limits:

• Eight hour time-weighted average (TWA): is the maximum average airborne concentration of a substance when calculated over an eight-hour working day, for a five-day working week.
• Short term exposure limit (STEL): is the time-weighted average maximum airborne concentration of a substance calculated over a 15-minute period. STELs are used where brief exposure can be harmful and can be measured.
• Peak limitation: is a maximum or peak airborne concentration of a substance determined over the shortest analytically practicable period of time which does not exceed 15 minutes.

Peak limits are not adjusted for longer or shorter working days.

No. The change from WES to WEL does not change your duties under Queensland’s Work Health and Safety Act 2011 and Work Health and Safety Regulation 2011. You must eliminate risks to health and safety so far as is reasonably practicable. If that is not reasonably practicable, you must minimise them so far as is reasonably practicable.

Under Queensland’s WHS laws, a PCBU must:

• eliminate risks to health and safety so far as is reasonably practicable, or, if elimination is not reasonably practicable, minimise those risks so far as is reasonably practicable
• ensure that workers and other persons are not exposed to airborne contaminants above the applicable workplace exposure limit
• undertake air monitoring where required by the WHS Regulation to assess exposure and confirm that control measures are effective.

For information about what is reasonably practicable, see Safe Work Australia’s interpretative guideline on the meaning of reasonably practicable.

1. Check your substances. Compare the substances you use, generate or handle with the WEL list and Safe Work Australia’s comparison table.
2. Review your documents. Update risk assessments, safe work procedures, training materials and records that refer to WES.
3. Review your monitoring and controls. Check that controls cover the full task, including cleanup, decontamination and re-entry, and that they follow the hierarchy of controls.

Until 30 November 2026, a PCBU must ensure no person is exposed above the relevant workplace exposure standard (WES). From 1 December 2026, the WEL list applies.

A change to a limit does not in itself mean a workplace is non-compliant. However, you must ensure no person is exposed above the limit that applies. Whether an exposure exceeds the applicable limit depends on your workplace's exposure levels, risk assessments and control measures.

The PCBU is responsible for managing a person’s exposure to airborne contaminants in a workplace. Workers should be consulted about risks and controls as required under the WHS Act.

Check the product’s safety data sheet (SDS) for its ingredients, then look up each ingredient on Safe Work Australia’s WEL list. Ingredients are normally identified by name and CAS number. Not every substance has a CAS number, and some entries, such as dusts and mixtures, are listed by name. If you can’t tell whether a substance is covered, contact your supplier or a suitably qualified person.

Safe Work Australia’s airborne contaminants hub has a comparison table of the former WES and the WEL list.

Review them anyway. Documents that refer to exposure standards or WES should use the correct terminology from 1 December 2026.

Queensland’s Work Health and Safety Regulation 2011 requires monitoring in certain circumstances. If you are uncertain whether a limit is being exceeded, or monitoring is otherwise required, you must do it. Monitoring should use recognised methods and be carried out by competent persons.

Existing results are useful for understanding trends and how well controls have worked. Review them against the revised limits and consider whether they still reflect current work practices, equipment, production rates and controls. If the data is limited, dated or no longer representative, further monitoring may be needed.

A revised limit does not in itself mean harm has occurred. However, exposure above the applicable limit is not acceptable. Review your risk assessment, monitoring data and controls, and act to eliminate or minimise the risk so far as is reasonably practicable.

Review your risk assessment and implement further reasonably practicable controls following the hierarchy of controls.

Not necessarily. It depends on the substance, the level of exposure, and how effective your current controls are.

1. Eliminate the hazard to remove the risk at the source or substitute with something less hazardous.
2. Use engineering controls (such as isolation or ventilation) to prevent hazards from coming into contact with workers.
3. Use administrative controls to establish work practices that reduce the duration, frequency, or intensity of exposure to hazards.
4. Personal Protective Equipment (PPE) worn by workers to reduce exposure to hazards.

Read more about the hierarchy of controls.

PPE should not be the sole control unless higher-order controls are not reasonably practicable. If PPE is used, it must be correctly selected, fitted and used.

Health monitoring requirements are set by the Work Health and Safety Regulation 2011 and depend on the hazardous substances or processes at your workplace. Review whether your current arrangements remain appropriate.

You can find the WEL list, comparison tables, transition resources, guidance material and frequently asked questions at Safe Work Australia’s Airborne Contaminants Hub.

No. Workplace Health and Safety Queensland provides general information about legislative requirements. Compliance depends on the circumstances of your workplace and cannot be determined without a detailed assessment of your workplace by a competent person, such as an occupational hygienist.

Workplace-specific advice on exposure assessment and controls may require a suitably qualified person, such as an occupational hygienist.

Visit the Australian Institute of Occupational Hygienists to find a list of occupational hygienists, including certified occupational hygienists who may be able to help in your workplace.

If you have further questions, you can contact Workplace Health and Safety Queensland on 1300 362 128.