Rationale behind Dangerous Goods Packing Instructions

International Maritime Dangerous Goods (IMDG) Code published by International Maritime Organization (IMO) is a mandatory instrument under The International Convention for the Safety of Life at Sea, 1974 (SOLAS) and The International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 (MARPOL).

The carriage of dangerous goods is prohibited except in accordance with the relevant provisions of chapter VII of SOLAS Convention and Regulation 1(2) of MARPOL Convention prohibits the carriage of harmful substances in ships except in accordance with the provisions of Annex III. These provisions are amplified in IMDG Code.

Regulation 1(3) of Chapter VII SOLAS states “Packaged form means the form of containment specified in the IMDG Code.” Further Regulation 1.1.2 of Annex III of MARPOL states “For the purposes of this Annex, “packaged form” is defined as the forms of containment specified for harmful substances in the IMDG Code.”

Above makes it a legal requirement for shippers to use only those packages authorized by IMDG Code for transporting Dangerous Goods and Harmful Substance by sea.

The rationale behind the packing instructions assigned to dangerous goods in IMDG Code varies from nature of hazard each goods pose and general hazard as per the common properties of dangerous goods.

Packing instructions are addressing the shipper or the person who prepares the package for dangerous goods transport and these instructions consist of (i) general instructions, (ii) specific instructions for particular hazards (iii) and for specialized dangerous goods.

General instructions consist of

  • packagings in accordance with part 6.1 of IMDG Code,
  • Pressure receptacles in accordance with part 6.2 of IMDG Code, packagings not subject to the provisions of parts 6.1, 6.2, 6.3, 6.5 or 6.6 of IMDG Code,
  • Intermediate Bulk Containers (IBC) in accordance with part 6.5 of IMDG Code
  • Large packagings in accordance with part 6.6 of IMDG Code

More specific instructions are based on certain general properties of dangerous goods.

Examples of General and Specific Packing instructions


P001 – Liquids

P002 – Solids

P003 – Articles



Class 1 (Explosives)     – P100 series

Explosives may differ in classification if packages are changed. Which means classification of explosives takes into consideration how it is packed. Hence packing also takes into consideration the robustness in handling rather than their appropriateness in transport

Class 2        – P200 series

P200 –         Compressed, Liquefied & Dissolved Gases and certain low boiling point substances not in Class 2

P201 –         Gas Sample – Non Pressurized

P203 –         Refrigerated Liquefied Gases

P205 –         Hydrogen in Metal Hydride Storage System

P206 –         Chemical Under Pressure

P207 –         Aerosols


Class 3        – P300 series

P300 –         Nitroglycerin Solution In Alcohol

P301 –         Aircraft Hydraulic Power Unit Fuel Tank

P302 –         Polyester Resin Kit

Class 4        – P400 series

P400 –         Certain Class 4.2 substances

P401 –         Certain Class 4.3 substances

Similarly, P402 to P411 is assigned to certain substances under Class 4



Class 5        – P500 series

P500 –         Oxygen Generator, Chemical

P501 –         Hydrogen Peroxide, Stabilized

P502 –         Perchloric Acid

P520 –         Organic Peroxides and Self-reactive substances under class 4.1


Class 6        – P600 series

P600 –         Tear gas candles and toxic ammunitions

P601 –         Certain highly toxic substances

P620, P621, P650 – Infectious Substances


Class 7

No packing instructions are assigned to radioactive materials. Packaging is as per IAEA guidelines.

Class 8       –

P800 –         Gallium and Mercury

P801 –         Batteries

P802 –         Highly corrosive substances

P803 –         Bombs, Smoke, Non-Explosive

P804 –        Bromine


Class 9       – P900 Series

P900  –        Fishmeal

P901  –        Chemical or First Aid Kit

P902  –        SAFETY DEVICES, Electrically Initiated (Airbags/Seatbelts)

P903 –             Lithium Batteries

P904    –           Genetically Modified Microorganisms

P905    –           Life-Saving Appliances, Self-Inflating/ Not Self-Inflating

P906    –           Polychlorinated Biphenyls


It is imperative that shippers look into the IMDG Code in force for packing of dangerous goods and adhere strictly to the type of packages authorized and quantity limitations in respective packing instructions.

Any noncompliance to packaging may result in accidents jeopardizing lives at sea