ADR at sea – transport of dangerous goods by ferry
The transport of dangerous goods by sea is subject to much stricter regulations than land transport. For the freight forwarder and carrier, the key moment is when they pass through the port gates, where ADR regulations give way to the International Maritime Dangerous Goods (IMDG) Code.
In this article, we explain how to avoid the most common mistake in ports: a lack of proper multimodal documentation.
ADR vs. IMDG – A game-changer at the port
Many carriers assume that a correct ADR entry on the CMR consignment note is sufficient to board a ferry. This is a mistake. Whilst the ADR regulates transport by road, the IMDG Code (International Maritime Dangerous Goods Code) sets out the safety rules on board a ship.
The moment the truck’s wheels touch the ferry ramp, the transport is no longer subject solely to road traffic regulations. It comes under the scope of international maritime regulations. The main reason for these restrictions is the specific nature of the vessel. The ferry captain/fire officer must know how to separate flammable cargo from oxidising cargo and where to position the trailer (e.g. on the open deck) so that a rescue operation is possible in the event of a fire.
| Category | Road Transport (ADR) | Maritime Transport (IMDG) |
|---|---|---|
| Legal basis | ADR Agreement | IMDG Code (Chapter 5.4) |
| Main document | Consignment note / CMR, ADR declaration | DGN (Dangerous Goods Note)
MDGF (Multimodal Dangerous Goods Form) |
| Securing of goods | Land transport standards (e.g. EN 12642 XL) | Packing certificate |
| Markings | Orange plates | Placards on all four sides of the unit |
Multimodal Dangerous Goods Form – The key to smooth clearance
Although the term ‘Dangerous Goods Note’ (DGN) is often used in the industry, the standard recommended by Pol-Agent and accepted by global shipping companies is the Multimodal Dangerous Goods Form.
Why do we prefer the multimodal approach? It is universal and complies with Chapter 5.4 of the IMDG Code. It brings together all the information required by ports, customs authorities and the ship’s crew.
Differences between DGN and MDGF:
1. Dangerous Goods Note (DGN)
A term originating mainly from the UK market and standards developed by SITPRO.
Application:Most commonly found in UK ports and on routes to that market.
Characteristics:A highly formal document, often printed on specific paper forms.
Flaw:It may be less clear to shipowners in other parts of the world if it is not fully compliant with the UN standard.
2. Multimodal Dangerous Goods Form (MDGF)
A modern ‘multimodal’ standard developed by international organisations (UN, IMO, ADR).
Application:A single document for combined transport: road + sea, rail + sea, etc.
Compatibility:Fully compliant with Chapter 5.4 of the IMDG Code.
Advantage:Accepted worldwide (Finnlines, Stena Line, Polferries). It features a standardised field layout that is easy for any shipowner to understand.
Key sections of the document that you need to pay attention to:
1. UN Number
Why is it crucial?? The captain uses this to check the segregation tables. An error here could result in substances being placed next to one another which, if they come into contact, pose a risk of explosion.
2. Packing Group
It specifies the hazard level of the substance:
- I – High hazard
- II – Medium hazard
- III – Low hazard
Note: Class 2 (gases) does not usually have this.
Flash Point
For flammable liquids (Class 3): The shipowner must know at what temperature the cargo will start to evaporate and form an explosive mixture in the hold.
Marine Pollutant / EmS Code
A declaration of harm to the aquatic environment and details of the emergency procedure (e.g. F-E, S-E) are required, which significantly speeds up clearance at the port.
Please note that a Multimodal document without a UN number and Packing Group (PG) is invalid. Furthermore, for sea transport, you must specify the flash point for liquid substances. Failure to include this single piece of information on the form may result in the trailer being prevented from boarding the ferry at the port
Checklist: 5 steps before boarding the ferry
Follow these guidelines to ensure your ADR transport runs smoothly:
The shipowner must approve the ADR class before the vehicle arrives at the port.
In maritime transport, warning labels (placards) must be displayed on both sides, the front and the rear of the trailer.
Make sure that the trailer has fully functional ferry strap attachment points.
Labels must not be dirty or peeling – they must be visible to staff in all weather conditions.
The driver must have up-to-date Written Instructions (in accordance with ADR 5.4.3).
IMDG pitfalls – When does a cargo that is ‘safe’ on the road become dangerous at sea?
Many shippers are under the impression that if a consignment does not have a UN number under the ADR classification, it does not require any additional formalities. This is a dangerous misconception. Maritime regulations (the IMDG Code) are much stricter due to the risk of fire in a ship’s enclosed hold.
Although hay is classified as a standard agricultural cargo in road transport, in maritime transport it is subject to paragraph 954 of the IMDG Code’s special provisions.
Risk:
Spontaneous combustion in the event of excessive humidity.
Requirement:
In order for cargo to be loaded onto the ferry, it is necessary to have a cargo surveyor’s certificate. The document must confirm that the moisture content of the goods is less than 14%. Without this certificate, the shipowner has the right to refuse loading on the grounds of a fire hazard.
The year 2026 saw a significant tightening of regulations regarding the popular charcoal.
How it was:
Until recently ‘Self-heating test certificate’ was sufficient to certify that the cargo is safe for maritime transport.
What will the situation be like from 2026?:
There has been an end to the redundancies. A full dangerous goods (DG) declaration is now mandatory for UN 1361. Every consignment must be accompanied by a document Multimodal Dangerous Goods Form and be treated as a full ADR/IMDG consignment.
There is a category of goods that a driver may transport without orange plates, but will be stopped at the port:
- Some types of fish meal: Risk of self-heating (UN 2216).
- Waste cotton: It may be classified as dangerous goods (UN 1365) if it is not properly compressed and packed.
- Some mineral fertilisers: Which may benefit from exemptions on the road, but are subject to strict segregation rules at sea (e.g. UN 2067).
Failing to recognise the differences between ADR and IMDG is the most common cause of problems at ports. When you book ferry crossings through Pol-Agent, you can be sure that your cargo will be checked for maritime safety before it even reaches the quay.
Do you need help with the IMDG?
IMDG regulations are constantly changing. If you are unsure whether your goods require an additional declaration or certificate, our dangerous goods experts are here to help.