What Is the IMDG Code? A Practical Guide to Dangerous Goods by Sea
If your business ships hazardous materials by sea, the International Maritime Dangerous Goods (IMDG) Code isn’t just another set of regulations; it’s the rulebook that determines whether your shipment moves safely and legally or gets stopped at the port.
In our experience delivering dangerous goods training, many organisations first encounter the IMDG Code when something goes wrong: incorrect documentation, rejected shipments, or uncertainty over classification. The Code is designed to prevent exactly those situations by setting clear international standards for transporting dangerous goods by sea.
This guide explains what the IMDG Code is, what it covers, and why understanding it is essential for anyone involved in maritime logistics.
What Does IMDG Stand For?
IMDG stands for International Maritime Dangerous Goods.
The IMDG Code is published by the International Maritime Organisation (IMO) and forms part of the SOLAS Convention, which governs safety at sea worldwide. In practical terms, this means the Code isn’t optional; it’s a legal requirement for most dangerous goods transported by sea.
You can view official guidance from the IMO here:
https://www.imo.org/en/OurWork/Safety/Pages/DangerousGoods.aspx
Why Does the IMDG Code Exist?
From a training perspective, the IMDG Code exists for one simple reason: dangerous goods behave differently at sea than they do on land.
Ships operate in confined environments, cargo is stacked tightly, and emergency response options are limited once a vessel leaves port. A small error in packaging, labelling or segregation can quickly become a serious safety issue.
The Code is designed to:
- Prevent fires, leaks and chemical reactions during transit
- Protect crew members and port personnel
- Reduce environmental risks to marine ecosystems
- Ensure consistent international shipping standards
Without these controls, transporting hazardous materials by sea would be extremely high-risk.
What Does the IMDG Code Actually Cover?
One of the most common misunderstandings we see in training is that people assume IMDG only relates to labelling. In reality, it covers the entire process of preparing dangerous goods for sea transport.
Classification
Every shipment must be correctly classified under the UN hazard system. This determines how the goods are packaged, labelled and handled.
Packaging
The Code sets strict standards for packaging, ensuring it can withstand movement, vibration and environmental conditions during maritime transport.
Marking and Labelling
Packages must clearly display hazard labels and UN numbers so risks are immediately visible during handling and stowage.
Documentation
A Dangerous Goods Declaration must accompany the shipment. Incorrect or incomplete paperwork is one of the most common reasons goods are rejected at ports.
Segregation and Stowage
Certain dangerous goods cannot be stored near each other. The IMDG Code specifies how cargo must be separated on board vessels to prevent hazardous interactions.
Training Requirements
Anyone involved in preparing, handling or managing dangerous goods shipments must receive appropriate IMDG training.
Who Needs to Follow the IMDG Code?
In practice, the IMDG Code applies to far more people than just shipping companies.
We regularly train staff across a wide range of roles, including:
- Manufacturers shipping products overseas
- Freight forwarders and logistics planners
- Warehouse and packing teams
- Export coordinators
- Port handling personnel
If your role involves preparing or shipping hazardous materials by sea, the IMDG Code applies.
Is the IMDG Code Mandatory?
Yes. The IMDG Code is a legal requirement under international maritime law.
Non-compliance can lead to shipment delays, enforcement action, fines and, more importantly, serious safety risks. Government guidance confirms that compliance is required when transporting dangerous goods internationally.
Why Training Matters in Real-World Operations
The IMDG Code is detailed and updated regularly, which is why training is essential.
In training sessions, we often see experienced logistics staff who are very capable in their roles but have never received formal IMDG instruction. Without proper training, even small mistakes in classification or documentation can lead to rejected shipments or safety hazards.
Training helps ensure staff can:
- Identify dangerous goods correctly
- Apply appropriate packaging requirements
- Complete documentation accurately
- Understand segregation rules
- Work confidently within compliance requirements
IMDG Training Courses by Total Compliance
If your organisation ships dangerous goods by sea, staff must be properly trained under IMDG requirements.
Total Compliance delivers expert-led IMDG training designed to provide a practical, real-world understanding of the regulations.
You can explore our courses here:
IMDG Full Course – Onsite
https://shop.totalcompliance.co.uk/international-maritime-dangerous-goods-imdg-course-imdgtr1
IMDG Full Course – Remote Online
https://shop.totalcompliance.co.uk/international-maritime-dangerous-goods-imdg-course-imdgtr2
IMDG Refresher Course – Onsite
https://shop.totalcompliance.co.uk/imdg-refresher-course-private-in-house-10-candidat-imdgtr3
IMDG Refresher Course – Remote Online
https://shop.totalcompliance.co.uk/imdg-refresher-course-private-online-remote-10-can-imdgtr4
Courses are available onsite or online, with certification typically valid for two years.
Need Guidance on IMDG Requirements?
If you’re unsure how the IMDG Code applies to your operations, or need support with training, classification or compliance, our team can help.
Total Compliance provides practical advice and expert-led IMDG training to ensure dangerous goods are prepared, documented and handled safely in line with international regulations.
Contact us today to discuss your requirements or arrange IMDG training for your team.