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 Revised Edition of the GHS.
- 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:
- Safe Work Australia’s Hazardous Chemical Information System
- The National Industrial Chemical Notification and Assessment Scheme Website
- The European Chemical Agency’s Information on Chemicals
- The New Zealand Chemical Classification and Information Database.
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.
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.
Under the model WHS Regulations chemicals must be classified as hazardous using the GHS 3rd Revised Edition. A copy of this can be downloaded from the United Nations Economic Commission for Europe website.
- the model Code of Practice: Labelling of Workplace Hazardous Chemicals
- the model Code of Practice: Preparation of Safety Data Sheets for Hazardous Chemicals
- Guidance on the Classification of Hazardous Chemicals under the Work Health and Safety (WHS) Regulations.
The GHS in Australia
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.
- GHS01—Exploding bomb
Explosion, blast or projection hazard.
- GHS02 – Flame
Flammable liquids, solids and gases; including self-heating and self-igniting substances.
- GHS03—Flame over circle
Oxidising liquids, solids and gases, may cause or intensify fire.
- GHS04—Gas cylinder
Gases under pressure.
- GHS05—Skull and crossbones
Fatal or toxic if swallowed, inhaled or in contact with skin.
- GHS06—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.
Corrosive chemicals, may cause severe skin and eye damage and may be corrosive to metals.
- GHS08—Health Hazard
Chronic health hazards; this includes aspiratory and respiratory hazards, carcinogenicity, mutagenicity and reproductive toxicity.
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.
The GHS uses ‘Danger’ and ‘Warning’ as signal words to indicate the relative level of severity of a hazard.
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).
- 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.
The GHS precautionary statements provide information to prevent and respond to chemical hazards, and store and dispose of a chemical.
For further information on hazard statements associated with particular classes see:
There are various training tools and resources available to help you understand the GHS.
- GHS Training Part 1—Introduction and GHS Training Part 2—Classification
- GHS Classification Training Question Sheet
- GHS Classification Training Answer Sheet
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.