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Hazard Classification

This page has not yet been updated to include information on the Globally Harmonised System (GHS) of hazard classification introduced in 2021.  See the Resources page of the Growsafe website for more information.

The HSNO Act requires all potentially hazardous substances in NZ to be evaluated and classified. These classifications include:

  • physical hazards
    • explosiveness
    • flammability
    • potential to oxidise
  • biological hazards
    • human toxicity
    • corrosiveness
    • ecotoxicity.

The HSNO hazard classification system provides agrichemical users with consistent information on potential agrichemical hazards. This is especially apparent with chronic toxicity (Classes 6.3-6.9) and ecotoxicity (Classes 9.1-9.4) classifications, for which information on product labels prior to HSNO was sometimes inconsistent or absent.

Within each hazard class, different levels of hazard are recognised using a letter ranking, where an 'A' generally represents the greatest potential hazard.

Each agrichemical can receive multiple hazard classifications. These classifications relate to a formulated trade-name product and reflect hazards from the active ingredient AND any other formulation constituents, e.g. the solvents used in EC formulations are usually toxic and flammable.

Hazard classification example: Diazinon 800
Class 3.1 Flammability Class 6 Toxicity Class 9 Ecotoxicity
3.1 C (Flammable liquids, medium hazard) 6.1C: Acutely toxic
6.3A: Irritating to the skin
6.4A: Irritating to the eye
6.8B: Suspected human reproductive or developmental toxicant
6.9A: Toxic to human target organs or systems
9.1A: Very ecotoxic in the aquatic environment
9.2D: Slightly harmful in the soil environment
9.3A: Very ecotoxic to terrestrial vertebrates
9.4A: Very ecotoxic to terrestrial invertebrates


View the full Hazard Classification tables on the next tab.

How many agrichemicals are classified as hazardous?

Agrichemicals are unusual in that they are deliberately released into the environment to kill things! Not surprisingly this means that agrichemicals exhibit many different biological hazard classifications. Biological hazard classes cover human toxicity (Class 6.1 relates to acute toxicity, Classes 6.3 to 6.9 relate more to chronic toxicity), corrosiveness (Class 8) and environmental toxicity (Class 9). (A full set of these descriptors is on another tab.)

Nearly half of the agrichemicals registered in NZ are classified as acutely toxic at some level. However, very few are considered toxic enough to require additional controls.  A Certified Handler must be involved in the storage, use and disposal of the most dangerous acutely toxic poisons (Classes 6.1A and 6.1B).  Note: prior to 1 December 2017, class 6.1C was also required to be under the control of an Approved Handler.

An important focus of the HSNO and RMA legislation is environmental protection. Most environmental toxins demonstrate greatest activity in water. Nearly three quarters of our agrichemicals considered toxic in water and a majority of these receive the highest aquatic hazard classification (9.1A). Only a very few agrichemicals are allowed to be applied directly into or over water, and there is a strong emphasis on managing agrichemical use to avoid potential contamination of surface and ground water (this is a responsibility of the suitably qualified person).

 High level environmental toxins (Class 9.1A aquatic toxins, 9.2A soil toxins, 9.3A vertebrate toxins, 9.4A invertebrate toxins) must be under the control of a suitably qualified person (eg GROWSAFE certified) if used in a wide dispersive manner or over water. Note: prior to 1 December 2017, Approved Handler status was required in this situation.