Hazard Diamonds & Classes

Introduction
Hazardous Chemicals and Dangerous Goods are transported throughout the United Kingdom, by road and by rail, every day. These goods include dangerous chemicals such as:

acids
toxins and carcinogenic substances
explosives
radioactive materials
inflammable liquids
volatile chemicals likely to spontaneously combust or react with air, water etc.; and
inflammable, poisonous or compressed gases

Although the Health and Safety Executive is primarily responsible for enforcing the many regulations designed to ensure safety while these substances are in transit, it is the members of the emergency services who will have to deal with the consequences of any incident.

Laid out below are the UN Hazard classes and danger signs. To find out what each Class number is and what each sign represents, please refer to the list at the foot of this page.

Class 1

Class 2 - Flammable Gas

Class 2

Class 3 - Flammable Liquid

Class 4.2 - Liable to Spontaneous Combustion

Class 4.3 - Flammable on contact with Water

Classes 3 and 4

Class 5.1 - Oxidising Agent

Classes 5 and 6

Class 7 - Radioactive Material

Class 7

Class 8 - Corrosive

Classes 8 and 9

UN Hazard Classes

Class Number	Hazard Class Information
Class 1	Explosive
1.1	Substances with a mass explosion hazard
1.2	Substances which present a projection hazard but no mass explosion hazard
1.3	Substances which present both a fire hazard and a minor blast or projection hazard (or both) but not a mass explosion hazard
1.4	No significant hazard
1.5	Very insensitive substances with a mass explosion hazard
1.6	Very insensitive articles with no mass explosion hazard
Class 2	Gases
2.1	Flammable gases
2.2	Non-flammable, non-toxic gases
2.3	Toxic gases
Class 3	Flammable liquids
Class 4	Flammable solids
Class 4.1	Flammable solids, self-reactive substances and solid desensitised explosives
Class 4.2	Materials liable to spontaneous combustion
Class 4.3	Substances which, in contact with water, release flammable gases
Class 5	Oxidizing substances and organic peroxides
Class 5.1	Oxidizing agents
Class 5.2	Organic peroxides
Class 6	Toxic and infectious substances
Class 6.1	Toxic substances
Class 6.2	Infectious substances
Class 7	Radioactive substances and articles
Class 8	Corrosive substances
Class 9	Miscellaneous dangerous substances and articles. Class 9 includes items such as asbestos, automotive airbags, lithium batteries and environmentally hazardous substances which don't fit into any of the other 8 classes.

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