IMDG Code Volume – 1 Explained

January 31, 2026 Jack

IMDG Code Volume 1 – Detailed Explanation

The IMDG Code Volume 1 is a core part of the International Maritime Dangerous Goods (IMDG) Code, which sets out mandatory global rules for the safe carriage of dangerous goods by sea. It is adopted by the International Maritime Organization (IMO) and made legally binding under the SOLAS Convention. Volume 1 mainly focuses on general provisions, definitions, classification principles, packing instructions, tank provisions, stowage, segregation, and operational requirements. In simple terms, it explains how dangerous goods must be prepared, packed, marked, labeled, documented, stowed, and segregated on board ships to reduce risks to life, ship, cargo, and the marine environment.

1. Purpose and Scope of IMDG Code Volume 1

The primary purpose of IMDG Code Volume 1 is safety. Dangerous goods such as explosives, flammable liquids, toxic substances, gases, corrosives, and marine pollutants can cause fires, explosions, pollution, or loss of life if mishandled. This volume provides standardized international rules so that all ships, ports, and authorities follow the same safety framework.

The scope of Volume 1 covers:

Dangerous goods carried in packaged form
Dangerous goods in portable tanks
Dangerous goods in road tank vehicles, rail tank wagons, and bulk containers carried on ships
Limited quantities, excepted quantities, and marine pollutants

It applies to all vessels engaged in international voyages, including container ships, general cargo ships, Ro-Ro vessels, and passenger ships.

2. Structure of IMDG Code Volume 1

IMDG Code Volume 1 is systematically arranged into Parts 1 to 7, each dealing with a specific safety aspect:

Part 1 – General Provisions, Definitions, and Training

This part introduces:

Legal status of the IMDG Code
Definitions of terms like dangerous goods, marine pollutant, UN number, competent authority
Training requirements for shore staff and ship’s crew

Training is mandatory and divided into:

General awareness training
Function-specific training
Safety training

This ensures that everyone involved understands the hazards and emergency procedures.

Part 2 – Classification

Part 2 explains how dangerous goods are classified into hazard classes based on their properties. There are 9 main classes, such as:

Class 1 – Explosives
Class 2 – Gases
Class 3 – Flammable liquids
Class 4 – Flammable solids
Class 5 – Oxidizing substances and organic peroxides
Class 6 – Toxic and infectious substances
Class 7 – Radioactive material
Class 8 – Corrosives
Class 9 – Miscellaneous dangerous substances

Correct classification is critical because packing, labeling, stowage, and segregation rules depend on it.

Part 3 – Dangerous Goods List (DGL)

Although the full Dangerous Goods List is printed in Volume 2, Volume 1 explains how to use the DGL. Each dangerous substance is assigned:

A UN Number
Proper Shipping Name (PSN)
Hazard class
Packing group (I, II, or III)
Stowage and segregation instructions
Emergency response references

This part teaches users how to interpret the list correctly for safe transport.

Part 4 – Packing and Tank Provisions

Part 4 specifies:

Packing instructions for each class of dangerous goods
Types of approved packaging (drums, jerricans, boxes, IBCs)
Tank requirements for portable tanks and tank containers

Packing Groups indicate danger level:

PG I – High danger
PG II – Medium danger
PG III – Low danger

Incorrect packing can lead to leakage, reactions, or explosions, so strict compliance is essential.

Part 5 – Consignment Procedures

This part covers administrative and identification requirements, including:

Marking and labeling of packages
Placards on containers and vehicles
Proper Shipping Name and UN Number marking
Marine pollutant mark
Dangerous Goods Declaration and documentation

Accurate documentation ensures that ship staff and emergency responders know exactly what hazards are on board.

Part 6 – Construction and Testing of Packagings

Part 6 describes:

Design standards for packagings
Testing procedures (drop test, leakproof test, stacking test)
Certification marks on packagings

Only UN-approved packagings that pass these tests may be used for dangerous goods.

Part 7 – Transport Operations (Stowage and Segregation)

This is one of the most important sections for ship officers. It explains:

Where dangerous goods may be stowed (on deck or under deck)
Stowage categories (A, B, C, D, E)
Segregation rules between incompatible substances

For example:

Flammable liquids must be kept away from oxidizing agents
Explosives have strict separation distances
Toxic substances must be separated from foodstuffs

Correct stowage and segregation prevent dangerous chemical reactions and fire spread.

3. Special Provisions and Exceptions

Volume 1 also explains:

Limited Quantities (LQ) – reduced requirements for small amounts
Excepted Quantities (EQ) – minimal regulation for very small packages
Special provisions for temperature-controlled substances
Rules for marine pollutants to protect the marine environment

These provisions help balance safety with practical shipping needs.

4. Importance for Ship Officers and Shore Staff

For deck officers (especially Third Officers), IMDG Code Volume 1 is vital for:

Preparing stowage plans
Checking segregation compliance
Verifying labels, placards, and documents
Responding to emergencies involving dangerous goods

For shore staff, it ensures:

Correct classification and packing
Legal compliance with international regulations
Reduced risk during loading, transport, and discharge

5. Safety and Environmental Protection

The IMDG Code Volume 1 is not only about ship safety but also environmental protection. Spills of chemicals or pollutants can cause long-term damage to marine ecosystems. By enforcing strict packaging, marking, and stowage rules, the code helps minimize pollution risks.

6. Conclusion

IMDG Code Volume 1 is the foundation of safe maritime transport of dangerous goods. It explains the principles behind classification, packing, labeling, documentation, stowage, segregation, and training. Without proper understanding and application of this volume, the risks of fire, explosion, toxic exposure, and pollution increase significantly.

For seafarers, especially deck officers, mastering IMDG Code Volume 1 is not just a regulatory requirement—it is a professional responsibility that directly protects lives, ships, cargo, and the marine environment.

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