User Guide to Thresholds and Classification - Environmental ...

7User Guide for Thresholds and ClassificationsClassification criteria for hazardous propertiesThe classification criteria for the HSNO Act hazardous properties are set out in Schedules 1 to 6 of theHazardous Substances (Classification) Regulations 2001.The classification systems comprise:numbered classes (for example, class 6), indicating the intrinsic hazardous property;numbered subclasses (for example, subclass 6.1), indicating the type of hazard; andlettered categories (for example, category A) indicating the degree of hazard.Exceptions to this are explosive substances, which are classified into a subclass (indicating the type ofexplosive hazard) and a category (indicating compatibility groupings) in the combinations permitted by theUnited Nations Recommendations on the Transport of Dangerous Goods Model Regulations (UnitedNations, 2007b). Categories for explosive substances do not indicate the degree of hazard. Other exceptionsare the two separate classifications for sensitisation, where a substance can be classified as both 6.5A(respiratory sensitisation) and 6.5B (contact sensitisation). Likewise, the 6.8C (causes developmental effectsvia lactation) category is independent of the other 6.8A and 6.8B categories. Further guidance is provided inthe relevant chapters for these properties.The combination of numbers and letters used in the classification system (eg, 6.1A) constitutes a hazardclassification of a substance.Classes for the hazardous propertiesThe nine classes for the hazardous properties are:class 1: explosiveness (see chapter 2 below);class 2: flammability, gases (see chapters 3 below and 4 below);class 3: flammability, liquids (see chapters 3 below and 5 below);class 4: flammability, solids (see chapters 3 below and 6 below);class 5: oxidising capacity (see chapter 7 below);class 6: toxicity (see chapters 9–17 below);class 8: corrosiveness (see chapter 8 for metal corrosivity below and chapter 11 for corrosion ofbiological tissues below); andclass 9: ecotoxicity (see chapters 18–23 below).Class 7 is unallocated in the HSNO Act classification system, because it is reserved for radioactivity, which isoutside the scope of the HSNO Act. Class 7 is used in the United Nations classification system for thetransport of dangerous goods for radioactive materials. In New Zealand, these substances are covered bythe Radiation Protection Act 1965, which is administered by the National Radiation Laboratory of the Ministryof Health.Similarly, subclass 6.2 is unallocated in the HSNO Act classification system for toxicity, because it isreserved in the United Nations classification system for the transport of dangerous goods for infectioussubstances. These are also outside the scope of the hazardous substances part of the HSNO Act.January 2012 EPA0109