New Workplace Exposure Levels (WEL) to Replace the Existing Workplace Exposure Standards (WES) 

16/05/2024by admin0Read: 5 minutes

In what has come as a significant move, the Workplace exposure standards for airborne contaminants (WES list) are evolving, transitioning to the Workplace exposure limits for airborne contaminants (WEL). This shift comes as part of the WES Review, with significant changes outlined for Australian businesses to be aware of.

After careful deliberation and extensive consultation, Australian Work Health and Safety (WHS) ministers have reached a consensus on updating the Workplace Exposure Standards (WES) to Workplace Exposure Levels (WEL), signifying a significant shift in occupational health and safety regulations.

Notably, the WES for welding fumes (not otherwise classified) will be reduced from 5 mg/m3 to 1 mg/m3, reflecting a heightened focus on worker safety and health.

Differences between WES and WEL

The Workplace Exposure Limits (WEL) stem from the comprehensive review of Workplace Exposure Standards (WES) for airborne contaminants, known as the WES review. This review meticulously evaluated evidence concerning the human health impacts of airborne contaminants (excluding asbestos) and proposed adjustments to ensure that standards are grounded in the highest quality contemporary evidence, supported by robust scientific methodologies.

Key Changes:

Key changes between the Workplace Exposure Standards for airborne contaminants and the updated WEL include:

1) Renaming:

Workplace Exposure Standards (WES) are now referred to as Workplace Exposure Limits (WEL), aligning with international standards and emphasising that these are exposure levels not to be exceeded, rather than merely best practice standards.

2) Modifications:

Some WEL for chemicals have been adjusted to reflect health-based recommendations from the WES review, although the majority of limits remain unchanged.

3) Additions:

New airborne contaminants have been included in the WEL, expanding the scope of regulated substances.

4) Removals:

Airborne contaminants prohibited for import, manufacture, and use under other Australian laws have been removed from the WEL, ensuring alignment with existing regulations.

5) Notation Changes:

The sensitiser notation used in WES has been replaced by more specific notations – respiratory sensitiser (RSEN) and dermal sensitiser (DSEN). Additionally, a new notation has been introduced for ototoxic substances, highlighting the increased risk of hearing loss when exposed in conjunction with noise.

More on Advisory Notations

The old, as well as the updated workplace exposure guidelines, include advisory notations to inform PCBUs about the additional risks posed by some airborne contaminants. These notations are defined as follows:

a) SK:

Absorption through the skin may be a significant source of exposure. Extra control measures should be used to minimise the risk of skin contact. These measures could include gloves, protective clothing, safety eyewear, and closed systems for transferring liquids or gases.

b) DSEN:

Substances that cause sensitisation through dermal (skin) absorption are given the notation ‘DSEN’. Sensitisation can occur even with low-level exposure over extended periods. Once sensitised, workers may react to the chemical even at concentrations below the exposure limit. Sensitised workers must not be exposed further to the substance.

c) RSEN:

Substances that cause sensitisation through respiratory tract absorption are given the notation ‘RSEN’. Sensitisation can occur even with low-level exposure over extended periods. Once sensitised, workers may react to the chemical even at concentrations below the exposure limit. Sensitised workers must not be exposed further to the substance.

d) OTO:

Ototoxic substances can increase the risk of hearing loss. Hearing loss is more likely if a worker is exposed to both noise and ototoxic substances than to either noise or the ototoxic substance alone.

These notations help PCBUs implement appropriate control measures to protect workers from the additional risks posed by these airborne contaminants.

6) Non-Threshold Genotoxic Carcinogens (NTGCs):

Thirty-three contaminants have been identified as NTGCs, with no safe exposure limit.

List of identified 33 NTGCs:

Below given is the list of all 33 thirty-three air contaminants, identified as NTGCs:

  1. Acrylamide
  2. Acrylonitrile (Vinyl cyanide)
  3. Allyl chloride (3-Chloro-1-propene)
  4. Allyl glycidyl ether (AGE, Allyl 2,3-epoxypropyl ether)
  5. Anisidine (o, p- isomers) (Methoxyaniline)
  6. o-Anisidine
  7. p-Anisidine
  8. Benzidine
  9. (bis)chloromethyl ether
  10. 1,3-Butadiene
  11. Catechol (Pyrocatechol, o-Dihydroxybenzene)
  12. beta-Chloroprene (2-Chloro-1,3-butadiene)
  13. Chromium VI compounds (including zinc chromates)
  14. Coal tar pitch volatiles (as benzene solubles)
  15. 1,2-Dibromo ethane (ethylene dibromide)
  16. 3,3′-Dichlorobenzidine
  17. Diethyl sulfate
  18. Dimethycarbamoyl chloride
  19. Dimethyl sulfate
  20. Dinitrotoluene
  21. Ethylene dichloride (1,2-Dichloroethane)
  22. Ethylene oxide (Oxirane)
  23. Ethylenimine (Aziridine)
  24. Hydrazine (Diamine)
  25. Lead chromate (as Cr)
  26. 4,4’-Methylene bis(2-chloroaniline) (MOCA, MBOCA, 2,2′-Dichloro-4,4′-methylenedianiline)
  27. 2-Nitrotoluene
  28. Propane sultone
  29. Polycyclic aromatic hydrocarbon (PAH) mixture when containing benzo[a]pyrene
  30. Tetranitromethane (TNM)
  31. Urethane
  32. Vinyl Bromide (Bromoethylene)
  33. Vinyl chloride, monomer (Chloroethylene)

Transition Period: 

WHS ministers have agreed upon a transitional period for the implementation of WEL, culminating on 30 November 2026, during which the revised WES will be phased out and replaced by the WEL.

From December 1, 2026, the Workplace Exposure Limits for airborne contaminants (WEL list) will be the same across Australia.

However, until December 1, 2026, PCBUs (businesses across WHS states, territories, and Victoria) must ensure that no person at the workplace is exposed to airborne concentrations exceeding the WES in the Workplace Exposure Standards for airborne contaminants as given in the WES list. They should take the necessary steps to mitigate risks.

Role of PCBUs after the Transition Period for WEL Ends

After the conclusion of the WEL transitional period, the model WHS Regulations will mandate that PCBUs:

  1. Guarantee that no individual within the workplace is subjected to an airborne concentration of a substance or mixture surpassing the corresponding WEL.
  2. Conduct air monitoring in instances where they lack reasonable certainty regarding whether the airborne concentration of a substance exceeds the WEL.

Role of Safe Work Australia: 

Safe Work Australia is committed to supporting businesses through this transition by providing comprehensive guidance and impact analysis on proposed changes to exposure standards for various airborne contaminants. Additionally, efforts are underway to determine the regulatory approach for non-threshold genotoxic carcinogens (NTGCs), for which safe exposure limits are not yet defined.

Ensuring Compliance: 

While most exposure limits remain unchanged, businesses need to stay informed about specific adjustments and adhere to the prescribed standards until the transition to WEL is complete. Anitech will continue to offer solutions outlining Safe Work Australia’s guidelines to facilitate a seamless transition for businesses and uphold workplace safety standards.

Units of Measurement for Airborne Contaminants

Exposure limits for fumes and dust (particulate contaminants) are expressed in milligrams of contaminant per cubic meter of air (mg/m³). For particulate contaminants, the Workplace Exposure Limit (WEL) applies to the inhalable fraction of particles unless specified otherwise for the respirable fraction.

The inhalable fraction consists of small particles that can easily enter the nose, mouth, and lungs through breathing. The respirable fraction (or respirable dust) includes very fine particles that can be inhaled deep into the lower lungs and is a subset of the inhalable fraction.

Some exposure limits for fibers, such as asbestos and synthetic mineral fibers, are measured in fibers per milliliter of air (f/mL) for the respirable fraction.

Exposure limits for gases and vapours are expressed as the number of parts of the contaminant per million parts of air (ppm). When a WEL is provided in both ppm and mg/m³, the ppm value should be considered exact, with the mg/m³ value used as a guide.

What’s coming next?

Following the WES Review, Safe Work Australia is engaged in additional initiatives:

  1. Development of new guidance to aid PCBUs in transitioning to the WEL. These resources will be made available gradually throughout the transition period and beyond.
  2. WHS ministers have requested further impact analysis on proposed changes to exposure standards for specific chemicals/substances. These include respirable crystalline silica, formaldehyde, benzene, chlorine, copper (fumes, dusts, and mists), hydrogen cyanide, hydrogen sulfide, nitrogen dioxide, and titanium dioxide.
  3. Determination of optimal regulation methods under the model WHS laws for 33 airborne contaminants classified as non-threshold genotoxic carcinogens (NTGCs), lacking a safe exposure limit.

How can Anitech Help?

Anitech’s Occupational Hygiene team can help organisations understand the key changes as well as help in implementing the same as per Safe Work Australia’s guidelines.

For more information and guidance on navigating these changes, businesses can reach out to Anitech’s Occupational Hygienist at 1300 802 163 or e-mail – sales@anitechgroup.com.

Together, we can foster safer and healthier work environments for all.


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