The maritime transportation is a vital artery of international trade, driving the exchange of goods and products that sustain our economy. However, this constant flow of goods is not without risk, especially when it comes to the transport of hazardous materials .

To ensure the safety of navigation, the protection of the environment and the health of people in ports and on board ships, the International Maritime Organization (IMO) has established a comprehensive set of regulations: the IMO Dangerous Goods Classification.

Throughout this comprehensive guide to the IMDG Code (International Maritime Dangerous Goods Code), we will explore the different categories of dangerous goods, labeling and packaging requirements, essential documentation and the responsibilities of the parties involved.

Get ready to acquire an in-depth knowledge of the IMO Dangerous Goods Classification, a fundamental tool to ensure safety and efficiency in the maritime transport of dangerous goods.


What is the IMDG code, the IMO Dangerous Goods Classification?

The IMO Dangerous Goods Classification, also known as the IMDG Code (International Maritime Dangerous Goods Code), is a set of international regulations established by the International Maritime Organization (IMO) for the safe transport of dangerous goods by sea.

Its main purpose is to prevent accidents and damages that may arise during the transportation of these goods, thus protecting human life, the environment and property.

The IMDG Code establishes strict criteria for the classification, labeling, packaging, stowage, handling and transport of a wide range of hazardous materials.


Scope of the IMDG Code

The IMDG Code applies to all dangerous goods carried by sea, including:

  • Explosive substances
  • Flammable gases
  • Flammable liquids
  • Flammable solids
  • Oxidizing substances and organic peroxides
  • Toxic and infectious substances
  • Radioactive materials
  • Corrosive substances
  • Miscellaneous hazardous substances


Organizations involved

The development and maintenance of the IMDG Code is a joint effort of IMO and several international organizations, including:

  • International Labor Organization (ILO)
  • World Health Organization (WHO)
  • Economic Commission for Europe (ECE)
  • International Civil Aviation Organization (ICAO)
  • International Hydrographic Organization (IHO)


Collaboration between these organizations ensures that the IMDG Code is kept up to date with the latest scientific and technical developments in the safety of the transport of dangerous goods by sea.


Dangerous goods categories: Navigating the diversity of hazards

The IMDG Code classifies dangerous goods into nine main classes, each with specific characteristics and hazards. Below is a summary of each class, including examples of products and their associated hazards:


Class 1: Explosives

Characteristics: Substances or devices that can explode under certain conditions.

Examples: Dynamite, fireworks, ammunition.

Hazards: Explosions, fires, projections of fragments.


IMDG Clase 1


Class 2: Gases

Characteristics: Compressed, liquefied or refrigerated gases.


2.1 Flammable gases.

2.2 Non-flammable and inert gases.

2.3 Toxic gases.

Examples: Propane gas, oxygen, chlorine.

Hazards: Asphyxiation, explosions, fire, poisoning.

IMDG Clase 2 - Gases


Class 3: Flammable liquids

Characteristics: Liquids that can easily ignite and give off flammable vapors.


3.1 Flammable liquids with low flash point.

3.2 Flammable liquids with medium flash point.

3.3 Flammable liquids with high flash point.

Examples: Gasoline, acetone, alcohol.

Hazards: Fires, explosions.

IMDG Clase 3 - Liquidos inflamables


Class 4: Flammable solids

Characteristics: Solid substances that can easily ignite and give off flammable gases.


4.1: Flammable solids susceptible to self-heating.

4.2: Substances liable to spontaneous ignition.

4.3: Substances that emit flammable gases when in contact with water.

Examples: Matches, phosphorus, magnesium.

Hazards: Fires, explosions.

IMDG Clase 4


Class 5: Oxidizing substances and organic peroxides

Characteristics: Substances that can easily release oxygen or that can decompose exothermically.


5.1: Oxidizing substances.

5.2: Organic peroxides.

Examples: Hydrogen peroxide, potassium nitrate, sodium chlorate.

Hazards: Fires, explosions, exothermic reactions.

IMDG Clase 5


Class 6: Toxic and Infectious Substances

Characteristics: Substances that can cause harm to human or animal health by ingestion, inhalation, contact with skin or mucous membranes.


6.1: Toxic substances.

6.2: Infectious substances.

Examples: Cyanide, arsenic, viruses, bacteria….

Hazards: Poisoning, infections, diseases.

IMDG Clase 6


Class 7: Radioactive materials

Characteristics: Materials that emit ionizing radiation.


7.1: Radioactive materials of limited activity.

7.2: High activity radioactive materials.

Examples: Uranium, plutonium, radioactive iodine.

Hazards: Radiation exposure, cancer, disease.

IMDG-Clase 7 - Material radiactivo


Class 8: Corrosive substances

Characteristics: Substances that can attack or destroy living tissues or materials by direct contact.


8.1: Substances corrosive to skin.

8.2: Substances corrosive to metals.

8.3: Corrosive substances that can attack other materials.

Examples: Sulfuric acid, sodium hydroxide, ammonia.

Hazards: Burns, eye damage, corrosion of materials.


Class 9: Miscellaneous hazardous substances

Characteristics: Substances which cannot be classified in any of the other classes, but which present specific hazards during transport.

Examples: Substances that give off heat, substances that can spontaneously combust, substances that can emit toxic gases in contact with water.

IMDG-Clase 7,8,9


Dangerous Goods Labeling and Marking: Speaking the Language of Safety

Correct labeling and marking of dangerous goods is a crucial aspect to ensure safety during their transport by sea. By providing clear and visible information on the nature of the risks associated with these goods, proper identification, handling and storage is facilitated, minimizing the possibility of accidents and damage.


Importance of labeling and marking

Clear identification of dangerous goods: Allows persons involved in the transport and handling of the goods to take the necessary precautions.

Communication of specific risks: Facilitates the adoption of appropriate safety measures for each type of dangerous goods.

Compliance with international regulations: The IMDG Code establishes specific labeling and marking requirements that must be met.


Types of labels and markings

Hazard labels: These are placed on the packaging of dangerous goods to indicate the hazard class to which they belong. Each class has a specific color label and symbol.

Handling marks: Indicate the precautions to be taken during handling and storage of dangerous goods. These markings may include instructions on stowage position, storage temperature and no smoking.

Danger panels: Used to indicate the presence of dangerous goods in containers or transport vehicles. These panels include information on the hazard class, the quantity of dangerous goods and the UN identification number.


Related content:


Dangerous goods packaging and stowage: Navigating a sea of requirements

Correct packing and stowage of dangerous goods is crucial to ensure safety during their transport by sea. These processes must comply with the regulations established in the IMDG Code for each class of dangerous goods, thus minimizing the risks of accidents, damage to the environment and human health.


Packaging requirements:

Material suitability: The packaging material must be compatible with the dangerous goods and resistant to their corrosive, flammable or toxic effects.

Structural strength: The packaging must have sufficient structural strength to withstand the weight and vibrations during sea transport.

Hermetic seal: The packaging must be airtight to prevent leakage or spillage of the dangerous goods.

Marking and labeling: The packaging must be properly marked and labeled according to the class of dangerous goods it contains.


Stowage requirements

Segregation: Dangerous goods of different classes must be segregated from each other to avoid dangerous reactions.

Ventilation: Dangerous goods that release gases or vapors should be stowed in well-ventilated areas.

Temperature control: Dangerous goods that are temperature sensitive must be stowed in temperature controlled areas.

Stowage compatibility: Dangerous goods must not be stowed together with incompatible materials that may generate dangerous reactions.


Packaging materials

Metals: Steel, aluminum, copper (for non-corrosive dangerous goods).

Plastics: Polyethylene, polypropylene, PVC (for non-flammable and non-corrosive dangerous goods).

Wood: Treated plywood (for non-flammable and non-corrosive dangerous goods).

Fiberglass: Glass fiber reinforced epoxy resin (for corrosive dangerous goods).

Tank containers: For bulk liquids and gases (must meet specific design and construction requirements).


Stowage techniques

Manual stowage: Used for small quantities of dangerous goods or in areas of difficult access.

Forklift stowage: Used for palletized or containerized dangerous goods.

Crane stevedoring: Used for heavy or large quantities of dangerous goods.


Potential hazards

Incorrect packaging or stowage: May cause leakage, spillage, hazardous reactions or damage to packaging.

Incompatibility of materials: May cause hazardous reactions, fires or explosions.

Lack of ventilation: May generate accumulation of toxic or flammable gases.

Unsuitable environmental conditions: May affect the integrity of the packaging or cause dangerous reactions in the goods.


Dangerous goods transport documentation: Navigating through a sea of paperwork

The Proper documentation is essential to ensure the safe transport of dangerous goods by sea. This documentation provides crucial information on the nature of the goods, their packaging, stowage and associated risks, enabling the competent authorities and the parties involved in the transport to take the necessary safety measures.


Required Documents

Dangerous Goods Declaration (DGD): The main document that provides detailed information on dangerous goods, including their classification, quantity, packaging, markings and labels, stowage and the name and address of the shipper and consignee.

Safe Stowage Certificate (SSC): Issued by the ship’s master, it certifies that the dangerous goods have been stowed in accordance with IMDG Code regulations and that the ship complies with the safety requirements for transport.

Other documents: In addition to the DGD and CSC, other specific documents may be required, such as the Dangerous Goods Emergency Plan (DMP), the Authorization for Stowage (ASE) or the Exemption Certificate.


Obtaining documentation

Dangerous Goods Declaration (DGD): The DGD must be prepared by the shipper of the dangerous goods and delivered to the ocean carrier. The ocean carrier should review the DGD for completeness and accuracy.

Safe Stowage Certificate (SSC): The SSC is issued by the ship’s master after the dangerous goods have been stowed on board and safety conditions have been verified.

Other documents: Requirements for obtaining other specific documents may vary depending on the type of dangerous goods, mode of transport and country of origin or destination. It is recommended to consult the competent authorities or an expert in the transport of dangerous goods to obtain precise information on the documents required in each case.


Importance of documentation

Compliance with regulations: Proper documentation demonstrates compliance with IMDG Code regulations and other international regulations applicable to the transport of dangerous goods.

Hazard communication: Documentation provides essential information on the risks associated with dangerous goods, enabling the parties involved to take appropriate precautionary and safety measures.

Facilitation of transport: Complete and accurate documentation facilitates the shipping process, streamlining procedures and reducing the risk of delays or problems.

Liability: In the event of an accident or incident, proper documentation can be crucial in determining liability and facilitating the investigation.

In the following section, we will address the responsibilities and obligations of the parties involved in the maritime transport of dangerous goods.


Responsibilities in the transport of dangerous goods: A coordinated dance for safety

The transport of dangerous goods by sea involves a complex web of responsibilities shared among various parties, each with a crucial role to play in ensuring a safe and incident-free voyage. Effective communication and coordination between these parties is essential to navigate the challenges and risks associated with this type of transportation.


Parties involved and their responsibilities

Shipper: Responsible for correctly classifying dangerous goods, packing them in accordance with regulations and providing accurate information on the Dangerous Goods Declaration (DGD).

Ocean Carrier: Responsible for accepting only dangerous goods that comply with regulations, ensuring safe transport on board the vessel, issuing the Safe Stowage Certificate (CSC) and complying with emergency procedures in the event of an incident.

Ship’s Master: Responsible for the overall safety of the ship and its crew, ensuring that dangerous goods are stowed and transported in accordance with the IMDG Code and relevant regulations, supervising loading and unloading operations, and taking the necessary measures in case of emergency.

Ship’s crew: Responsible for handling dangerous goods in accordance with established safety procedures, using appropriate personal protective equipment and following the captain’s instructions in case of emergency.

Competent authorities: Responsible for establishing and enforcing national and international regulations for the transport of dangerous goods, supervising shipping operations, investigating incidents and taking sanction measures in case of non-compliance.


Importance of communication and coordination

Effective communication and coordination between the different parties involved are essential to ensure the safe transport of dangerous goods. This involves:

Sharing accurate and complete information: Information on the nature of dangerous goods, their packaging, stowage and potential hazards must be communicated clearly and accurately between all parties.

Coordinate operations: Loading, unloading, stowage and transportation activities must be carefully coordinated to minimize risks and ensure safety.

Establish clear communication channels: Clear and effective communication channels should be established to allow for the timely exchange of information, especially in the event of an emergency.


International regulations and standards

The transport of dangerous goods by sea is regulated by an international framework of rules and regulations established by the International Maritime Organization (IMO). The IMDG Code is the main instrument that sets out the detailed requirements for the classification, packing, labeling, stowage and transport of dangerous goods by sea.

In addition to the IMDG Code, there are other relevant regulations, such as the MARPOL 73/78 Convention and its protocols, which address the prevention of marine pollution from ship operations, including the discharge of hazardous and noxious substances.

Compliance with these international regulations and standards is mandatory for all countries involved in the maritime transport of dangerous goods, ensuring a uniform and harmonized approach to safety in this area.


Across Logistics: Your partner for safe international dangerous goods logistics

At Across Logistics, we understand the complexity and challenges associated with dangerous goods shipping. That’s why we specialize in offering comprehensive international logistics solutions that ensure regulatory compliance, safety and efficiency at every stage of the process.

Our experience and expertise in the handling of dangerous goods allow us:

Correct classification of goods: Our experts identify the hazard class to which each good belongs and ensure its classification in accordance with the IMDG Code.

Proper packaging and labeling: We provide high-quality, heavy-duty packaging that meets the specific requirements of each type of dangerous goods.

Preparing the necessary documentation: We prepare the Dangerous Goods Declaration (DGD) and any other documents required for safe transport by sea.

Coordinate stowage and transport: We work closely with reliable ocean carriers to ensure safe on-board stowage and smooth transport.

Offer expert advice: Our team of professionals is available to provide personalized advice to our clients on regulations, procedures and best practices in the transportation of dangerous goods.


With Across Logistics, companies can:


Reduce risks: Minimize the possibility of accidents, environmental damage and penalties for non-compliance with regulations.

Optimize efficiency: Streamline transportation processes and reduce costs thanks to our experience and expertise.

Gain peace of mind: Be confident that your dangerous goods are transported safely and responsibly, meeting the highest industry standards.


At Across Logistics, we are committed to being your strategic partner in international dangerous goods logistics. We invite you to contact us to learn how we can help you navigate the complexities of this industry and ensure safe, efficient and worry-free transportation.