IMO Class

Description

Class 1

Explosives

1.1

Substances and articles which have a mass explosion hazard.

1.2

Substances and articles which have a projection hazard but not a mass explosion hazard.

1.3

Substances and articles which have a fire hazard and either a minor blast hazard or a minor projection hazard or both, but not a mass explosion hazard.

1.4

Substances and articles which present no significant hazard.

1.5

Very insensitive substances which have a mass explosion hazard.

1.6

Extremely insensitive articles which do not have a mass explosion hazard.

Class 2

Gases: Compressed, Liquefied or Dissolved under Pressure

2.1

Flammable gases

2.2

Non-Flammable gases

2.3

Toxic gases

Class 3

Flammable Liquids

Class 4

Flammable Solids or Substances

4.1

Flammable solids

4.2

Substances liable to spontaneous combustion

4.3

Substances which, in contact with water, emit flammable gases.

Class 5

Oxidizing Substances (agents) and Organic Peroxides

5.1

Oxidizing substances (agents) by yielding oxygen increase the risk and intensity of fire

5.2

Organic peroxides - most will burn rapidly and are sensitive to impact or friction

Class 6

Toxic and infectious Substances

6.1

Toxic substances

6.2

Infectious substances

Class 7

Radioactive Substances

Class 8

Corrosives

Class 9

Miscellaneous dangerous substances and articles (Marine pollutants which are not of an otherwise dangerous nature are listed in class 9)

MHB

Materials hazardous only in bulk (The regulations for materials hazardous only in bulk are not applicable to these materials when they are carried in closed freight containers, however, many precautions may have to be observed)