Dangerous goods are divided into the following classes according to the international regulations of the IMDG Code (International Maritime Dangerous Goods Code):


Class 1: Explosives
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, but not a mass explosion hazard.
Division 1.4 Substances and articles which present no significant hazard.
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.


Class 2: Gases
Class 2.1 Flammable gases
Class 2.2 Nonflammable, nontoxic gases.
Class 2.3 Toxic gases.


Class 3: Flammable Liquids


Class 4: Flammable Solids
Class 4.1 Flammable solids, self-reactive substances and desensitized explosives.
Class 4.2 Substances liable to spontaneous combustion.
Class 4.3 Substances which, in contact with water, emit flammable gases.


Class 5: Oxidizing Substances and Organic Peroxides
Class 5.1 Oxidizing substances.
Class 5.2 Organic peroxides.


Class 6: Toxic and Infectious Substances
Class 6.1 Toxic substances.
Class 6.2 Infectious substances.


Class 7: Radioactive Material


Class 8: Corrosive Substances


Class 9: Miscellaneous Dangerous Substances and Articles