HSNO Classification in New Zealand

In New Zealand, hazardous substances are classified using the UN GHS, 7th revised edition (2017), as adopted and modified by the EPA's Hazardous Substances (Hazard Classification) Notice 2020. The EPA issued it under section 74 of the HSNO Act 1996 and it has applied since 30 April 2021. A substance only counts as a "hazardous substance" under the Act if it can be classified under that Notice. Classification is mostly self-assessed by the importer or manufacturer, and the result decides which approval and labelling, SDS and packaging rules apply.

Approach: I read the 2020 Notice and the EPA's Guide to classifying hazardous substances in New Zealand (October 2021) on the EPA site, and pulled worked examples from the EPA's Chemical Classification and Information Database (CCID). The text of the HSNO Act itself on legislation.govt.nz was not part of this check.

1. Legal basis

• The Notice was signed 15 October 2020, notified in the Gazette 29 October 2020, and has been in force since 30 April 2021. It replaced the Hazardous Substances (Classification) Notice 2017 and the Minimum Degrees of Hazard Notice 2017 (Notice 2020, pp. 2, 4–6).
• It sets the classification system for the Act, its regulations, EPA notices, group standards and approvals, and for any other law that relies on HSNO classifications (cl. 3).
• Minimum degree of hazard (cl. 5): "A substance is not a hazardous substance for the purposes of the Act unless it can be classified in accordance with this notice."
• Exclusions:
  • Medicines (cl. 6): not covered unless an approval was already in force. They "must be treated as" hazardous if they are classifiable and either fall under s 3(1)(b)(i) of the Medicines Act 1981 or are being registered under the ACVM Act 1997.
  • Food (cl. 7): not covered unless an approval was already in force.
  • Psychoactive substances (cl. 8): not covered if they are approved products, or if they would only be classifiable because of their psychoactive properties.

2. How New Zealand departs from GHS 7

A substance is "correctly classified" if it follows the GHS as modified by the Notice. Where the two conflict, the Notice wins (cl. 10(2)–(3)).

Categories not adopted (cl. 10(4)):

• acute toxicity Category 5 (oral, dermal, inhalation)
• skin irritation Category 3
• aspiration hazard Category 2
• aquatic acute Categories 2 and 3
• hazardous to the ozone layer

Eye irritation: Category 2 is used, but the 2A and 2B subcategories are not; those substances go into Category 2 (cl. 10(5)).

Other NZ-specific points:

• Gases under pressure and aerosol Category 3 are classified whether or not the gas itself is hazardous (cl. 11).
• Explosives: UN compatibility groups are part of the classification (cl. 12).
• Mixtures:
  • The GHS mixture rules apply, except that Schedule 2 replaces some GHS tables (cl. 13).
  • Where GHS offers optional cut-offs, New Zealand chose the lower ones (EPA Guide, p. 5).
  • Examples (Notice, pp. 20–22):
    • Skin sensitiser Cat 1 or 1A: ≥ 0.1%; 1B: ≥ 1.0%.
    • Carcinogen Cat 1 or 2: ≥ 0.1% for the matching category.
    • Reproductive toxicant Cat 1, Cat 2 or lactation effects: ≥ 0.1%.
    • STOT single or repeated exposure Cat 1 ingredient: ≥ 10% makes the mixture Cat 1; 1.0% up to (not including) 10% makes it Cat 2.
  • M-factors "must be used" in the aquatic summation method (cl. 14).

3. Extra NZ-only class: hazardous to the terrestrial environment (cl. 15)

This class applies only to agrichemicals, or to active ingredients used to make pesticides or veterinary medicines. Timber treatments, antisapstain chemicals and antifouling paints are excluded. It has four classifications:

• Hazardous to soil organisms: plant or soil invertebrate EC50 of 100 mg/kg dry soil or less over 14 days, or a 25% reduction in microbial respiration or nitrification at 100 mg/kg or less after 28 days.
• Hazardous to terrestrial vertebrates: acute bird or mammal oral or dermal LD50 of 2000 mg/kg bw or less, or dietary LC50 of 5000 ppm or less, or chronic MATC of 100 ppm or less.
• Hazardous to terrestrial invertebrates: acute oral or contact LD50 of 25 µg per invertebrate or less.
• Designed for biocidal action: a fallback for biocides that do not already qualify under the aquatic class or the three classes above. It does not cover biocides aimed at internal organisms in humans or other vertebrates, viruses, protozoa or bacteria.

4. Old HSNO codes (6.1A, 9.1A and so on)

The old alpha-numeric codes no longer apply. Where another law still refers to a pre-2021 code, that reference "must be treated as" pointing to the equivalent GHS classification in the Schedule 3 correlation tables (cl. 16). Some examples (Notice, pp. 23–28):

Pre-2021 HSNO	GHS 7 equivalent
3.1A–3.1D	Flammable liquids Cat 1–4
6.1A–6.1D	Acute toxicity Cat 1–4 (6.1E has no equivalent: Cat 5 not adopted)
6.3A / 6.3B	Skin irritation Cat 2 / no equivalent (Cat 3 not adopted)
6.7A / 6.7B	Carcinogenicity Cat 1 / Cat 2
8.2A–C / 8.3A	Skin corrosion 1A–1C / Serious eye damage 1
9.1A	Aquatic acute 1 and chronic 1
9.2, 9.3, 9.4	Soil organisms, terrestrial vertebrates, terrestrial invertebrates

5. Who classifies, and what it triggers

• The EPA says "If you import or manufacture a hazardous substance (product), you are responsible for knowing its hazardous properties." You can classify yourself, use a consultant, or pay the EPA for a formal determination (EPA, How to classify).
• For mixtures, testing the whole product is recommended; otherwise you use mixture rules based on the ingredients' classifications.
• The classification decides whether a product can go under a group standard or needs an individual approval, and drives labelling, packaging and SDS requirements.
• For a substance with an approval, its hazard classification is the one the EPA gave it under the Notice's criteria. For a substance without one, it is whatever criteria it meets (cl. 9).

6. The CCID: EPA classifications for single substances

The CCID lists the EPA's classifications for individual chemicals, which you can use as ingredient inputs. Two entries:

• Ethanol (HSR001144, "Approved with controls"): Flam. Liquid 2 (H225) and Eye Irrit. 2 (H319), along with the key study data ^[1].
• Chlorothalonil (HSR002825): Acute Tox. 2 (inhalation, H330), Eye Damage 1, Skin Sens. 1, Carc. 2, STOT RE 1, Aquatic Acute 1 and Chronic 1 with acute and chronic M-factors of 10, plus the NZ-only "Hazardous to soil organisms" and "Hazardous to terrestrial vertebrates" ^[2].

7. Transition

The EPA has published a notice titled "Transitional period in Labelling, Safety Data Sheet and Packaging Notices ended on 30 April 2025". I couldn't open its text, so its detailed terms aren't confirmed here.

If you share a product's composition, I can work through its NZ classification ingredient by ingredient using the CCID entries.