The international maritime dangerous goods (IMDG) code.



The International Maritime Dangerous Goods or IMDG Code was adopted in 1965 as per the SOLAS (Safety for Life at Sea) Convention of 1960 under the IMO.

The IMDG code also ensures that the goods transported through seaways are packaged in such a way that they can be safely transported.


  • The seafarer should be able to classify dangerous goods and identify the shipping names of dangerous goods.
  • He/she should know how the particular IMDG cargo should be packed, Marked, lebelled, stowed and segregated.
  • He should understand different types of markings, labels or placards used to address various dangerous goods
  • Must know safe practice to load/unload the cargo unit carrying the IMDG product


The dangerous goods code is a uniform code. This means that the code is applicable to all cargo-carrying ships around the world.


  • Class 1 is for explosives. The same classification has six sub-divisions for materials which pose a high explosive risk, low explosive risk. Example RDX, Ammunition.
  • Class 2 is for gases. compressed, liquefied or dissolved under pressure.This clause has three sub-categories that talk about gases that are highly inflammable, that are not inflammable and gases that neither inflammable nor toxic
  • Class 3 is for Flammable liquids and has no sub-divisions.
  • Class 4.1 Flammable liquids – Zinc dust, Textile waste, Paints
  • Class 4.2 Substance liable to spontaneous combustion Iron and steel.
  • Class 4.3 Substance which in contact with water emit flammable gases – Sodium, Potassium, Calcium.
  • Class 5 .1 is for substances that have the oxidizing substance example – Sodium peroxide.
  • Class 5.2 Organic peroxides like Peroxyacetic Acid , Decanoyl peroxide.
  • Class 6.1  is for all kinds of substances that are toxic example tear gas.
  • Class 6.2 Infectious substance – Biological substances.
  • Class 7 is specifically for materials that are radioactive – Thorium, Isotopes of cesium.
  • Class 8 is for materials that are corrosive – Sulphuric acid, Caustic soda.
  • Class 9 is Miscellaneous Dangerous substances like fertilizers.




  • Packaging should be constructed and closed so as to prevent loss of contents by vibration or by change in temperature, humidity or pressure under normal transport condition.
  • No residue of dangerous cargo shall stick to the outside of packages, whether new, reused, reconditioned or remanufactured.
  • Part of the packing that is in direct contact with the dangerous good should not get affected. (weakened, react, Penetrate etc)
  • Packaging should be successfully tested for Vibration, Drop test as provided in the code.
  • Cushioning and absorbent material should be inert and suitable to nature of content.
  • Nature and thickness of the packing should be enough to withstand heat generated due to friction while transporting without any problem.
  • Dangerous goods should not be packed together with other substance if they react dangerously .
  • Ullage should be kept sufficient for expansion during transportation.


  • Label shows the class number and dangerous properties of the goods in pictorial symbols as illustrated in the code.
  • They are 100mm by 100mm
  • Placards are 250mm by 250mm, contains the same information but in a bigger size and are fixed to the cargo transport unit.
  • The proper shipping name and UN number should be marked.
  • These marking, lebels & placards shall be readily visible.
  • Marking, lebels, placards should be still identifiable if kept immersed in sea water for 3 months.
  • Large packaging should be marked on two opposing sides and Placards on a CTU (Cargo Transport Unit) shall be placed on four sides.
  • IBC packaging should be marked on two opposing sides and Placards on a CTU (Cargo Transport Unit) shall be placed on four side.
  • Radioactive materials shall be marked with the name of consignor or consignee or both if over 50Kgs


  • A dangerous good transport document includes a paper document as well as provision of the same information by Electronic data processing.
  • If offered as Electronic means , consignor must be able to present paper documents without delay.
  • Document must contain the below data in sequence –
    • Name and address of consignor and consignee of dangerous goods.
    • Date when it was prepared.
    • UN number (Always starts with UN)
    • Proper shipping name
    • Technical name
    • Primary hazard class, division and compatible group
    • Subsidiary hazard class or division
    • Packaging group
    • Total quantity of dangerous good


  • Stowage means proper placement of DG good to ensure safety of ship, cargo and environmental protection during transport.


The IMDG Code defines “segregation” as the process of separating two or more substances or articles which are considered mutually incompatible wen their packing or stowage together may result in undue hazards in case of leakage, spillage or any other accident. Segregation is obtained by maintaining certain distances between incompatible dangerous goods, by requiring the presence of one or more steel bulkheads or decks between them, or a combination of the previous methods.

To determine the segregation for two classes, you would read a row for one class (across) and for the other class read a column (down). Where they intersect, you will either find the letter “X” or a number. The numbers (1, 2, 3 or 4) will tell the people stowing the goods how far apart they must be separated, as follows:

“1” – “away from” (normally, CTUs at least 3 metres apart)

“2” – “separated from” (normally, CTUs at least 6 metres apart)

“3” – “separated by a complete compartment or hold from”

“4” – “separated longitudinally by an intervening complete compartment or hold from”

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