Under the HSNO Act, a hazardous substance is any substance that has one or more of the following properties, above specified levels:

• an explosive nature (including fireworks)
• flammability
• ability to oxidise (i.e. accelerate a fire)
• corrosiveness
• acute or chronic toxicity (toxic to humans)
• ecotoxicity, with or without bioaccumulation (i.e. can kill living things either directly or by building up in the environment)
• can generate a hazardous substance on contact with air or water.

Hazardous substances can have more than one hazardous property. For example, methylated spirits and petrol are flammable and toxic.

Below find the hazardous substance classification used in New Zealand under the HSNO Act, grouped into physical, health and environmental hazards, and with a classification number assigned to each type of hazard. In the related content on our other pages, there is useful information on how to measure the hazardous properties of a substance.

If the substance has any hazardous properties, then it is a hazardous substance under the HSNO Act. If it doesn't have any hazardous properties, then the substance can be considered non-hazardous and you don't need to worry about approval under the HSNO Act.

If you are importing or manufacturing it yourself, you must determine whether it is hazardous. If you are given a safety data sheet for the substance, it may give information about whether the substance should be considered hazardous.