Workplace exposure standards

The workplace exposure standards (WES) is a list of hazardous chemicals and their maximum exposure limits. This list also contains information about: 

  • Carcinogenicity 

  • Skin and respiratory sensitisation 

  • Whether an airborne chemical moves into the body through the skin. 

 The WES list is currently under review.  

There are limits to the exposure workers can have to hazardous airborne chemicals. The current limits are published in the Workplace exposure standards for airborne contaminants list. 

WES values 

WES values are generally based on the adverse effect of the lowest airborne concentration of the chemical, called the ‘critical effect’. 

There are 3 WES parameters under the model work health and safety (WHS) laws: 

  • if the critical effect on a worker is chronic or sub-chronic over an 8 hour time weighted average (a worker’s average airborne exposure in any 8 hour work shift of a 40 hour week) 

  • if the critical effect over a short term exposure limit is short term or acute, for example the effect occurs after a 15 minute exposure 

  • peak limitation – not exceeding 15 minutes. 

WES are under review  

We first adopted workplace exposure standards (WES) for airborne contaminants in 1995. But there have been significant advances in toxicology and recommendations for airborne hazardous chemicals since then.  

WES are under review to ensure they are: 

  • based on the highest quality, contemporary evidence 

  • supported by a rigorous scientific approach. 

Public feedback on draft reports for airborne contaminants in releases 2 to 14 closed on 1 February 2021. Public feedback for final draft reports (release 15) closed on 30 July 2021.  

Subscribe to the chemical exposure standards mailing list to stay informed about the WES.  

Aim of the review 

The review aims to develop a list of health-based recommendations for WES in Australia. It includes values, notations and a list of hazardous chemicals. All the information is publicly available. 

A report will be published for each chemical for public feedback

WHS Ministers will consider all WES recommendations and stakeholder feedback and make the decisions. 

When changes to WES standards are adopted in WHS laws throughout Australia, they will become mandatory. There will be a 3-year transitional period for compliance. 

Review of WES 2021 standards


Selection of trusted sources 

Selected, trusted sources will inform updates to the WES, including: 

  • composing the list 

  • how each chemical is assessed and recommended. 

A WES recommendation evaluates both primary and secondary sources of data as the basis of their decisions. If there are significant gaps or any uncertainty in the primary sources, secondary sources will be included. 

Primary sources 

The following bodies met the criteria for trusted primary sources of data: 

  • American Conference of Governmental Industrial Hygienists (ACGIH®) – Threshold Limit Values (TLV) 

  • Deutsche Forschungsgemeinschaft (DFG) – Maximum workplace values (MAK values) 

  • EU Scientific Committee on Occupational Exposure Limits (SCOEL) – Occupational exposure limits (OEL) 

  • American Industrial Hygiene Association/Occupational Alliance for Risk Science (AIHA/OARS) 

  • Health Council of the Netherlands (Dutch Expert Committee on Occupational Safety) 

Secondary sources 

The following bodies met the criteria for trusted secondary sources of data: 

  • UK Health and Safety Executive 

  • Australian Institute of Occupational Hygienists (AIOH) position papers – recommendations for WES 

  • Nordic Council: The Nordic Expert Group for Criteria Documentation of Health Risks of Chemicals 

  • Australian Industrial Chemicals Information Scheme (AICIS)

  • Australian Pesticides and Veterinary Medicines Authority (APVMA) 

  • The European Chemicals Agency (ECHA) 

  • The International Agency for Research on Cancer (IARC) 

  • National Toxicology Program (NTP) 

  • US Environmental Protection Agency (US EPA) 

  • Organisation for Economic Cooperation and Development (OECD) 

  • US National Institute for Occupational Safety and Health (NIOSH) 

Notation recommendations 

Advisory notations accompanying the workplace exposure standards include: 

  • carcinogens (Carc. 1A, Carc. 1B, Carc. 2) 

  • sensitisers (Sen) 

  • chemicals where significant absorption and toxicity may occur via the dermal route (Sk). 

Under the model WHS laws, the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) classifies hazardous chemicals

The following bodies inform carcinogenicity and sensitiser notations for the workplace exposure standards in this review: 

  • Australian Industrial Chemicals Information Scheme (AICIS)

  • Australian Pesticides and Veterinary Medicines Authority (APVMA). 

  • The European Chemicals Agency (ECHA). 

  • European Union’s Annex VI to CLP. 

Information available in the primary and secondary sources can also inform whether a classification or notation may be required. 

Selecting hazardous chemicals to be added to or removed from the WES list 

Criteria for identifying chemicals to be added or removed from the WES list ensure it reflects Australian workplaces. 

The chemicals identified were made available for public consultation through the regulation impact analysis process and were considered by our members. 

The lists of chemicals meeting the agreed criteria will be included among the hazardous chemicals that will either be added to or removed from the WES list. 

The chemicals being added to the WES list will be evaluated in the WES review.  

Recommending health-based workplace exposure standards and notations 

Each chemical’s WES recommendation will follow a consistent process of decision making and evaluation. 

First, information will be evaluated from: 

  • primary data sources 

  • supporting information from secondary sources, where appropriate. 

These include values and notations for: 

  • carcinogenicity 

  • sensitisation of the skin or respiratory tract 

  • the risk of the chemical being absorbed through the skin. 

This may result in a recommendation to keep, amend or withdraw the existing WES value or notation. 

In some cases, there may not be enough data to make a recommendation. Or there could be uncertainty about the data. 

In these cases, an interim WES value may be recommended. This could either be further assessment of the chemical’s data, or a priority evaluation of the chemical’s data in the next WES review. 

An independent expert will peer review each evaluation. 

When the evaluations and peer reviews are done, each evaluation report for a chemical will be on our consulting platform, for public feedback

Criteria for a skin notation 

Some chemicals on the WES list pose a risk of being absorbed through the skin. An ‘Sk’ notation on the WES list alerts you to this risk. 

This notation has been applied, based on evidence from trusted sources.  

Non-threshold based genotoxic carcinogens 

Some of the chemical characteristics on the WES list mean that all exposure poses a risk to health.  

These chemicals have been identified and calculated to find out if there is any minimum level of exposure. 

Immediately dangerous to life or health 

Some chemicals on the WES list will have a parameter set as immediately dangerous to life or health (IDLH)  

The US National Institute for Occupational Safety and Health (NIOSH) developed this parameter to represent an airborne concentration of a chemical that can do any of the following: 

  • cause death 

  • cause immediate or delayed permanent adverse health effects to a worker 

  • impede a worker’s escape from such an environment. 

An IDLH parameter is not considered an exposure standard. It is a concentration that may cause harm, rather than a concentration with no adverse effects expected. 

However, an IDLH parameter means you and your workers have more safety information for specific situations, such as: 

These parameters can guide planning for accident prevention and emergency response in the workplace. 

Regulation impact statement – WES framework 

The regulation impact statement had 2 parts: 

  • consultation regulation impact statement (consultation RIS) 

  • decision impact statement (decision RIS) 

The consultation RIS 

In 2018, we published a consultation RIS to determine the impact of, and best way to implement, an update to Australia’s WES framework. 

The consultation RIS: 

  • outlined and tested the current state of knowledge about the costs and benefits of the status quo 

  • presented potential options to address the problems with the current WES framework. 

It explored whether the WES should remain mandatory under the model WHS laws or if advisory status is more appropriate. It also explored changing the name of WES to workplace exposure limits (WEL).  

A 6-week consultation period then supported the consultation RIS. 

We received 31 submissions with valuable feedback from stakeholders, including: 

  • WHS regulators 

  • government 

  • industry and industry groups 

  • unions 

  • professionals and other interested or affected people.  

The consultation summary, submissions are on our consultation platform

The decision RIS 

The decision RIS – Workplace exposure standards framework under the model Work Health and Safety laws – reflected consultation outcomes. 

The decision RIS was ready to provide a recommendation to WHS Ministers on: 

  • the preferred option to implement an update to Australia’s WES 

  • the status of the WES under model WHS laws. 

Outcomes of the RIS 

A majority of WHS ministers agreed to the preferred option in the decision RIS. This means: 

  • no change to the requirement to ensure exposure standards for substances and mixtures are not exceeded (Regulation 49) 

  • the WES for airborne contaminants will be updated, using the agreed methodology 

  • the name of workplace exposure standards will be changed to workplace exposure limits (WEL). 

A standard 3-year transitional period applies for duty holders to comply with amendments to the WES. 

Educational and guidance materials will support implementation and compliance. 

We will work closely with the Commonwealth, state and territory WHS regulators to implement the preferred option. 


Email us at if you have questions or want more information about WES and the review. 

Supporting information