Regulatory framework
The IMDG Code
The IMO code governing dangerous goods carriage by sea, its amendment cycle, and the segregation and stowage rules that shape a booking.
Last reviewed 2026-08-28
Read this as orientation, not as authority
This page summarises a regulatory position for planning purposes. It may contain errors or omissions, it is not legal, safety or regulatory advice, and the underlying rules are amended on cycles of their own. Nothing here states what hansa express holds or is approved for. Confirm the current requirement with the competent authority, or ask us about your actual consignment, before you act on it.
What the IMDG Code is
The International Maritime Dangerous Goods Code is the International Maritime Organization's instrument for the carriage of dangerous goods in packaged form by sea. It has been mandatory under Chapter VII of the SOLAS Convention since 1 January 2004, and it also gives effect to the marine pollutant provisions of MARPOL Annex III.
Mandatory status matters for how it is used. The Code is not carrier guidance that can be varied by agreement: it is given force through the flag state and enforced through port state control, and a consignment that does not conform is one a master is entitled to refuse and an inspector is entitled to detain.
It is amended on a two-year cycle, in step with the UN Model Regulations. Each amendment is normally available for voluntary application for a period before becoming mandatory, so — as with ADR — two editions can be validly in use at once and a booking should be documented against a stated amendment.
How the Code is arranged
- Volume 1 carries the general provisions: classification, packing and tank provisions, consignment procedures, construction and testing of packagings, and the provisions on transport operations.
- Volume 2 carries the Dangerous Goods List, the limited quantities schedules, the index, and the appendices. This is where an entry's stowage category, segregation group and special provisions are read from.
- The Supplement carries the material used when something goes wrong or when the cargo needs support: the Emergency Response Procedures for Ships Carrying Dangerous Goods (the EmS Guide), the Medical First Aid Guide, reporting procedures, and packing guidance for cargo transport units.
Segregation and stowage
Segregation is the Code's central operational concept and it is expressed in graded terms rather than as a single rule. The four levels run from “away from”, through “separated from” and “separated by a complete compartment or hold from”, to “separated longitudinally by an intervening complete compartment or hold from”. A segregation table pairs classes against each other, and segregation groups handle chemical families that need keeping apart for reasons the class alone does not capture.
Stowage category tells the ship where a consignment may go — on deck or under deck, and under what conditions. For Class 1 the stowage categories are specific to explosives, and they are the reason two explosive consignments that look commercially similar can have quite different implications for a vessel's cargo plan.
The practical effect for a shipper is that acceptance is not only about the box. It is about what else is already booked on that sailing. A consignment can be entirely compliant and still be declined for a particular vessel because the segregation it requires cannot be achieved alongside cargo already loaded.
Documentation, and the separate question of the port
The core documents are the dangerous goods declaration from the shipper and, where the goods are packed in a cargo transport unit, the container or vehicle packing certificate. Both are shipper responsibilities, both are checked, and an error in either is a routine cause of a consignment being stopped at the gate rather than at sea.
It is worth being clear about a distinction that catches people out. The IMDG Code governs carriage by sea. It does not decide what a port or terminal will handle. National port regulations, the harbour authority's own dangerous goods rules, explosives anchorages, notice periods, quantity thresholds and direct-delivery requirements are separate instruments administered by separate bodies.
A consignment can therefore be fully IMDG-compliant and still have nowhere to load, which is why port and terminal acceptance for Class 1 is settled before a sailing is booked rather than after.
Common questions
Is the IMDG Code voluntary guidance or law?
It is mandatory. The Code has been given effect under SOLAS Chapter VII since 1 January 2004, applied through flag state law and enforced through port state control. Individual amendments have a voluntary period before they become mandatory, but the Code itself is not optional.
Does IMDG compliance mean a port will accept the cargo?
No, and this is the most common misunderstanding in maritime dangerous goods. The Code governs carriage by sea. Port and terminal acceptance is governed separately, by national port regulations and the harbour authority's own rules, which set notice periods, quantity thresholds, permitted berths and sometimes a requirement that explosives are delivered direct to the ship without storage. Both questions have to be answered.
What is the difference between “separated from” and “away from”?
They are two of the four graded segregation levels. “Away from” requires effective separation such that incompatible goods cannot interact dangerously in an accident, and permits carriage in the same compartment or hold subject to a minimum horizontal distance. “Separated from” is stricter, generally requiring separation by a deck or an intervening space. The Code's segregation table sets which level applies to which pairing.
How often does the Code change?
On a two-year cycle, aligned with the UN Model Regulations. Each amendment normally has a period in which it may be applied voluntarily before it becomes mandatory, so it is worth agreeing with the carrier which amendment a shipment is documented against.
Sources and verification
Planning a movement like this?
Send the cargo, the two ends of the lane and the date. If we cannot move it ourselves we will tell you who can — same day.