• Joseph O'Donnell

Dangerous Goods: hazard class types

Updated: Sep 10

Hazardous or dangerous goods are general terms used to categorize commodities that pose a risk to life, health, property and the environment. Dangerous goods are classified by the specific risk they present.


According to the International Marine Dangerous Goods Code (IMDG Code), there are 9 different hazard classes.


Class 1: Explosives

These are commodities that contain explosive substances. Explosives are broken down into 6 divisions to further classify the type of explosion risk of the good.

  • Division 1.1: Substances and articles which have a mass explosion hazard

  • Division 1.2: Substances and articles which have a projection hazard but not a mass explosion hazard

  • Division 1.3: Substances and articles which have a fire hazard and either a minor blast hazard or a minor projection hazard or both

  • Division 1.4: Substances and articles which present no significant hazard; only a small hazard in the event of ignition or initiation during transport with any effects largely confined to the package

  • Division 1.5: Very insensitive substances which have a mass explosion hazard

  • Division 1.6: Extremely insensitive articles which do not have a mass explosion hazard

Common examples of explosive goods are ammunitions, fireworks and airbag inflators.

Class 2: Gases

Gases are broken down into three different divisions: 2.1 flammable, 2.2 non-flammable and 2.3 toxic gases. Common Examples are aerosols, pressurized or liquefied gasses and carbon dioxide.

Class 3: Flammable liquids

These are liquids which emit flammable vapors at a certain temperature, referred to as the flash point, which can ignite in the presence of a spark or flame. Common examples are some adhesives, gasoline, acetone and kerosene.


Class 4: Flammable Solids; substances liable to spontaneous combustion; substances which, in contact with water, emit flammable gases

This class is broken up into three divisions: 4.1 flammable solids, 4.2 spontaneously combustible and 4.3 dangerous when wet. Common examples are matches, sulphur and certain metal powders


Class 5: Oxidizing substances and organic peroxides

These substances are split into two sub-divisions: 5.1 oxidizing substances and 5.2 organic peroxides. These substances risk releasing oxygen which can cause other materials to combust. Goods in class 5.2 are thermally unstable and can burn rapidly, explosively decompose and more. Common examples in this class are hydrogen peroxide and ammonium nitrate fertilizers.


Class 6: Toxic and infectious substances

Class 6 is divided into 6.1 toxic substances and 6.2 infectious substances. Examples include: Lead compounds, bacteria, cyanide, pesticides, medical waste and more.

Class 7: Radioactive material

This class requires extensive training and specialized certifications just to handle the documentation, not including the materials. These materials are heavily regulated under the IMDG code. Radioactive substances are categorized as radioactive I, radioactive yellow II, radioactive yellow III and fissile materials. Common examples are uranium, plutonium, some medical equipment and radioactive ores.

Class 8: Corrosive substances

This class does not contain any subdivisions, and it is categorizes substances that can cause damage to living tissue and destroy other surrounding materials during leakage. Common examples are sulfuric acid, battery acids and strong bases like sodium hydroxide (A.K.A. Lye).


Class 9: Miscellaneous dangerous substances and articles

Goods that do not quite fit the classification of any of the previous classes are classified under class 9. This class has no subdivisions. Some examples are dry ice, asbestos and discarded/uncleaned containers.

Marine Pollutants:

Many of the dangerous goods in the 9 classes mentioned above are also considered marine pollutants. Marine pollutants are goods that if leaked or dumped into the ocean can cause severe damage to the sea life, water quality and shore lines.



It is the manufacturer and shipper's responsibility to understand and provide all necessary safety, packaging and handling information when shipping dangerous goods. This information is included on the Dangerous Goods Declaration (DG declaration) and Safety Data Sheet (MSDS/SDS), which must be provided to the carrier prior to shipping.


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