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Classification is the systematic identification of a chemical’s hazards.

Classification is based on defined criteria for each hazard as set out in the GHS. For example:

  • A chemical’s acute toxicity category is based on how much of the chemical is needed to poison someone.
  • A chemical’s flammability category is based on how easily the chemical will ignite.

Manufacturers and importers of chemicals that are supplied to workplaces are required by the model WHS Regulations to:

  • Determine if a chemical they import or manufacture is hazardous.
  • If the chemical is hazardous, correctly classify it according to the 3rd or 7th Revised Edition of the GHS (GHS 3 or GHS 7).

The hazard classification of a chemical determines what information must be included on labels and SDS to comply with model WHS Regulations.

  • If the classification of a hazardous chemical changes or new information comes to light, the label and SDS must be reviewed and revised.

Finding classifications for existing chemicals

There are many national and international sources for chemical hazard classifications.

Lists of classified substances like the Hazardous Chemical Information System are not mandatory under the model WHS Regulations and should be used for guidance only. It is the classification criteria that are mandatory. 

Some key resources include:

If the chemical has previously been classified under a different system of classification, such as the Approved Criteria for Classifying Hazardous Substances, it may be possible to translate the existing hazard classification to a GHS classification.

For more information on this process please refer to the Guidance on the Classification of Hazardous Chemicals under the Work Health and Safety (WHS) Regulations.

Classifying new chemicals

Where a chemical is new or has no existing classification that can be used the classification must be made using physical and health hazard data. This option involves:

  • Collecting available information or carrying out tests.
  • Evaluating the adequacy and reliability of the information.
  • Making a decision on classification based on the GHS classification criteria and decision logic.

This is sometimes referred to as classifying from first principles and requires specialist expertise and judgment. Classifiers will need to refer to the criteria and decision logic in the GHS.

  • If you need help determining the classification of a chemical you should talk to the supplier or manufacturer of the hazardous chemical. If you need further assistance—or if you are the manufacturer—we recommend you engage a suitable expert with experience in GHS classification.

We are not able to recommend service providers or classify a chemical on your behalf.

Classifying mixtures

Classifiers have a number of ways to determine the classification of a chemical mixture. The two main methods are:

  • Calculating the hazardous properties of the mixture based on the properties of its ingredients.
  • Testing the mixture as a whole to see how it behaves in practice.

If a mixture has been tested the results should always be used for classification; this method provides more accurate results than relying on calculations. Testing should also be considered for complex mixtures and ingredients that may have compounding or inhibiting effects that are hard to predict.

If there is no available test data for the mixture then it is essential to obtain a list of ingredients, their percentage content and their individual GHS classifications.

The mixture’s classification can be determined by comparing the ingredient details to the criteria and decision logic for classifying mixtures as described in the GHS. 


The GHS was developed by the United Nations to create a single, global methodology for chemical classification and hazard communication using labelling and SDS. It gives users practical, consistent and easy to understand information on chemical hazards and helps them take the appropriate preventive and protective measures for their health and safety. Australia adopted the 3rd revised edition of the GHS (GHS 3) on 1 January 2012 and will begin transitioning to the 7th revised edition of the GHS (GHS 7) on 1 January 2021. More information about the transition can be found in Adoption of GHS 7, below. 

Under the model WHS Regulations chemicals must be classified as hazardous using the GHS 3rd Revised Edition.  GHS. In Australia, the GHS is supported by:

A copy of the GHS can be downloaded from the United Nations Economic Commission for Europe website.

Adoption of GHS 7

From 1 January 2021, Australia will begin a two-year transition from GHS 3 to GHS 7. The transition period will finish on 30 December 2022. 

During the transition, manufacturers and importers may use either GHS 3 or GHS 7 for classifications, labels and safety data sheets of hazardous chemicals. From 1 January 2023 only GHS 7 may be used. 

Suppliers and users of hazardous chemicals may continue to supply and use chemicals manufactured or imported before 1 January 2023 that are classified and labelled under GHS 3, until their stocks run out. However, suppliers and users of hazardous chemicals should not supply or receive stock manufactured or imported after 31 December 2022 if they have labels or SDS prepared under GHS 3.

Key changes under GHS 7 are:

  • the ‘Flammable Aerosols’ hazard class will be renamed to ‘Aerosols’ and will incorporate non-flammable aerosols in a new category ‘Aerosols Category 3’
  • the existing flammable gas category (Category 1) will be split into two new categories (Flammable gas Category 1A and Category 1B)
  • the introduction of 3 new flammable gas categories:
    • Pyrophoric gas
    • Chemically unstable gas A
    • Chemically unstable gas B
  • the introduction of a new hazard class for desensitised explosives
  • updated precautionary statements.

Alongside the transition to GHS 7, the definition of ‘hazardous chemical’ under the model WHS laws is being clarified ensure it captures all Category 2 eye irritants including those that fall under Category 2B. This will be done by removing Category 2B eye irritants from the list of exempt hazard classes and categories.

More information about the changes under GHS 7 can be found on the GHS 7 - transition page.

Special arrangements for 1 July 2020 to 1 January 2021

Australia’s transition to GHS 7 was originally intended to start on 1 July 2020, however the transition was delayed due to the COVID-19 pandemic. To ensure that any importers and manufacturers that had already begun work on implementing GHS 7 are not disadvantaged, state and territory governments agreed to put in place regulatory arrangements allowing businesses to start classifying and labelling chemicals in accordance with GHS 7 from 1 July 2020. Suppliers and end users will also be able to supply and use GHS 7 labelled chemicals under these arrangements. For more information about the arrangements in place in your area, you should contact your local WHS regulator

Information about the regulatory arrangements in each state and territory will be published on the GHS 7 – transition page when it becomes available.

The GHS in Australia

Some GHS hazard classes and categories are not covered by the model WHS Regulations. To find out more refer to the definition of hazardous chemicals in the model WHS Regulations.

Australia has adopted its own cut off concentrations for certain hazard classes of chemicals, including for:

  • respiratory and skin sensitisers
  • chemicals that cause cancer
  • reproductive toxicants
  • chemicals that cause damage to organs from singe or repeated exposure.

A full list of cut off concentrations for use in Australia can be found on the Hazardous Chemical Information System.

Hazard communication under the GHS

The GHS sets out the way information about the hazards of chemicals and the precautions necessary to ensure safe storage, handling and disposal is explained to those using them.

  • The GHS uses pictograms, signal words and hazard and precautionary statements to communicate hazard information.

The GHS does not change the primary duties for businesses managing hazardous chemicals in the workplace.


There are nine hazard pictograms in the GHS that represent the physical, health and environmental hazards of chemicals.

Pictogram of an explosion
GHS01  — Exploding bomb
Explosion, fire, blast or projection hazard.
Pictogram of a flame over a line
GHS02 – Flame
Flammable liquids, vapours, solids and gases; including self-heating and self-igniting substances.
Pictogram of a flame over a circle
GHS03 — Flame over circle
Oxidising liquids, solids and gases, may cause or intensify fire.
Pictogram of a gas cylinder
GHS04 — Gas cylinder
Gases under pressure.
Pictogram of corrosive materials
GHS05 — Corrosion
Corrosive chemicals, may cause severe skin and eye damage and may be corrosive to metals.
Pictogram of a skull and crossbones
GHS06 — Skull and crossbones
Fatal or toxic if swallowed, inhaled or in contact with skin.
Pictogram of an exclamation mark
GHS07 — Exclamation mark
Low level toxicity. This includes respiratory, skin, and eye irritation, skin sensitisers and chemicals harmful if swallowed, inhaled or in contact with skin.
Pictogram of a body indicating a health hazard
GHS08 — Health Hazard
Chronic health hazards; this includes aspiratory and respiratory hazards, carcinogenicity, mutagenicity and reproductive toxicity.
Pictogram of environmental damage
GHS09 — Environment
Hazardous to aquatic life and the environment.

High resolution versions of the GHS pictograms (and Dangerous Goods class labels) can be downloaded from the United Nations Economic Commission for Europe website.

Signal words

The GHS uses ‘Danger’ and ‘Warning’ as signal words to indicate the relative level of severity of a hazard.

Danger is used for a more severe or significant hazard, while Warning is used for less severe hazards.

Hazard and precautionary statements

Hazard statements are assigned to a class and category and describe the nature of the hazard of a chemical including, where appropriate, the degree of hazard. For example, the hazard statement ‘Toxic if swallowed’ is the hazard statement for Acute toxicity category 3 (Oral).

For more information on hazard statements associated with particular classes see:

Precautionary statements describe the recommended measures that should be taken to minimise or prevent adverse effects resulting from exposure, or improper storage or handling of a hazardous chemical. This includes information about how to prevent and respond to emergencies, and how to store and dispose of the chemical. 

  • GHS 7 includes updates to many precautionary statements, making them easier for users to read. GHS Revision 7 also provides greater flexibility in the use of precautionary statements, including combining precautionary statements and allowing for changes to wording if it does not affect the safety message.
  • On 1 January 2021, precautionary statements from either GHS 3 or GHS 7 may be used. Due to the flexibility allowed by GHS 7, the precautionary statements from GHS 3 may continue to be used even after the transition to GHS 7 ends.
  • There may also be new precautionary statements under GHS 7 that manufacturers and importers must add to relevant labels and SDS. 

For more information about the requirements for precautionary statements please refer to the Manufacturers and importers of workplace hazardous chemicals – transition to GHS 7 information sheet. 

Further advice

SWA is not a regulator and cannot advise you about chemical classification compliance. If you need help, please contact your state or territory work health and safety authority.



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