Classes for Dangerous Goods

Class 4.3: Substances which, in contact with water, emit flammable gases.

IMO Classes

Class 1.
Explosives Class 2.
Gases Class 3.
Flammable Liquids Class 4.1.
Flammable Solids or Substances Class 4.2.
Flammable solids Class 4.3.
Substances which, in contact with water, emit flammable gases Class 5.1.
Oxidizing substances (agents) by yielding oxygen increase the risk and intensity of fire Class 5.2.
Organic peroxides - most will burn rapidly and are sensitive to impact or friction Class 6.1.
Toxic substances Class 6.2.
Infectious substances Class 7.
Radioactive Substances Class 8.
Corrosives Class 9.
Miscellaneous dangerous substances and articles

Substances which, in contact with water, emit flammable gases

Dangerous When Wet material is a material that when it makes contact with water is liable to become spontaneously flammable or give off flammable or toxic gas at a rate greater than 1 L per kilogram of the material per hour.