IMO Classes for Dangerous Goods

The Carriage of dangerous goods and marine pollutants in sea-going ships is respectively regulated in the International Convention for the Safety of the Life at Sea (SOLAS) and the International Convention for the Prevention of pollution from Ships (MARPOL).

Relevant parts of both SOLAS and MARPOL have been worked out in great detail and are included in the International Maritime Dangerous Goods (IMDG) Code, thus making this Code the legal instrument for maritime transport of dangerous goods and marine pollutants. As of 1st January 2004, the IMDG Code will become a mandatory requirement.

Classification of dangerous goods
For all modes of transport (sea, air, rail, road and inland waterways) the classification (grouping) of dangerous goods, by type of risk involved, has been drawn up by the UNITED NATIONS Committee of Experts on the Transport of Dangerous Goods (UN).

Class 1. Explosives

Depending on the risk of mass explosion or fire causing projection

Consists of explosives that have a mass explosion hazard. A mass explosion is one which affects almost the entire load instantaneously.
Consists of explosives that have a projection hazard but not a mass explosion hazard.
Consists of explosives that have a fire hazard and either a minor blast hazard or a minor projection hazard or, both but not a mass explosion hazard.
Consists of explosives that present a minor explosion hazard. The explosive effects are largely confined to the package and no projection of fragments of appreciable size or range is to be expected. An external fire must not cause virtually instantaneous explosion of almost the entire contents of the package.
Consists of very insensitive explosives. This division is comprised of substances which have a mass explosion hazard but are so insensitive that there is very little probability of initiation or of transition from burning to detonation under normal conditions of transport
Consists of extremely insensitive articles which do not have a mass explosive hazard. This division is comprised of articles which contain only extremely insensitive detonating substances and which demonstrate a negligible probability of accidental initiation or propagation

Class 2. Gases

Liquefied, compressed or refrigerated. Classified in: asphyxiating, oxidising, flammable or toxic.

Flammable gases. They can be ignited by a heat source. Eg. Propylene, ethane or butane.
Non-flammable gases, non-toxic. Displace oxygen causing suffocation. Eg. Helium, oxygen.
Toxic gases. Inhalation may cause acute effects or even death. They may be flammable, corrosive or oxidizing. Eg. Chlorine

Class 3. Flammable Liquid

Flammable liquids and insensitive explosive liquids. Example: Turpentine, gasoline, paints, varnishes, etc.

Class 4. Flammable Solid

Flammable solids, self-reactive or explosive desensitized. These can react spontaneously.
Spontaneously flammable substances. They may ignite spontaneously when heated, when in contact with air or while being transported.
Substances which in contact with water, emit flammable gases. Eg. Sodium, potassium, carbide, etc.

Class 5. Organic Peroxides

Oxidizing. Liquids or solids that support combustion, can favor the development of fires.
Organic peroxides. They derived from hydrogen peroxide. You can only be loaded into a loading unit in certain quantities. .

Class 6. Toxic, Poison substances

Toxic substances. They can cause death by inhalation, skin absorption or ingestion. Eg. Methanol or methylene chloride.
Infectious substances. Contain pathogens (microorganisms) that can cause disease. Eg. Material for making vaccines, secretions, blood, laboratory cultures, etc.

Class 7. Radioactive Substances

They contain radionuclides. Eg uranium, plutonium, thorium.

For packages with a maximum radiation level at the surface of 0.5 millirem / h or containers that do not contain packages with higher categories.
For packages with a radiation level in the largest area to 0.5 millirem / h, not to exceed 50 millirem / h.
For packages with a maximum surface radiation level at 200 millirem / h, or for containers whose transport index is less than or equal to 1.0 and carrying bundles visible category III.
Fissionable materials.

Class 8. Corrosives

Destructive effect upon contact. Eg. Sulfuric acid, sodium hypochlorite.

Class 9. Miscelaneous

A material which presents a hazard during transportation but which does not meet the definition of any other hazard class.