Oxidising substances and organic peroxide pose a hazard because of their ability to chemically oxidise matter, including living tissue. Strong oxidisers can greatly enhance the flammability of other material.


Division 5.1 - Oxidising Substances


Although these substances are not necessarily combustible in themselves, they may readily yield oxygen and

in so doing cause or contribute to the combustion of other materials.


Division 5.1 substances can be in UN Packing Groups I, II, or III.


Division 5.2 - Organic Peroxides


Organic peroxides are substances which may be considered derivatives of hydrogen peroxide. Organic peroxides

are thermally unstable and may emit heat and give off harmful or flammable gases or vapours whilst undergoing

exothermic, self-accelerating decomposition. The rate of decomposition increases with temperature and varies

with the organic peroxide formulation. Additionally, they may be liable to explosive decomposition, burn rapidly,

be sensitive to impact or friction, react dangerously with other substances, or cause damage to eyes.

The substances of Class 5.2 are subdivided as follows: 

  • P1 Organic peroxides, not requiring temperature control  

  • P2 Organic peroxides, requiring temperature control.


Division 5.2 organic peroxides when packaged for transport are assigned to an alphabetical classification system whereupon type A is the highest risk and is forbidden for transport, and type G poses the least risk and is exempt from the requirements of the ADG Code. Organic peroxides of types B-F must be transported in accordance with NSW Dangerous Goods Road & Rail Transport regulations.

Some organic peroxides are required to be desensitised by organic liquids or solids, inorganic solids, or water. Others are required to be subjected to temperature control during transport.

All Division 5.2 substances are assigned to UN Packing Group II.