Dangerous Goods (IMDG) Shipping Reference
What the nine hazard classes cover, what each of the four segregation terms actually demands, and the documents, marks and deadlines a dangerous goods container booking needs. A plain-English orientation for exporters shipping DG for the first time.
Segregation between specific classes is decided by the IMDG Code's own segregation provisions, read together with the entry for each UN number, the stowage location and the type of container. Those requirements are safety-critical and we do not reproduce or approximate them here. Take the actual segregation decision from the Code itself, from your carrier's dangerous goods desk, or from a qualified DG advisor — never from a summary, including this one.
Classification of a particular product is decided by its entry in the Code's dangerous goods list, not by which description here sounds closest. Your supplier's safety data sheet should state the proper shipping name, UN number, class or division and packing group.
When a carrier tells you two consignments must be "separated from" each other, it is using one of four defined terms. Each demands a structurally different kind of separation on board, and they form a ladder: every step adds a physical barrier the one below it does not require.
The Code expresses each of these terms differently depending on whether the goods are in packages or in a container, whether the container is closed or open, and whether it is stowed on deck or under deck — and it sets the exact separations for each case. Quoting one figure out of that structure is how people end up applying an on-deck rule to an under-deck stow. Read the requirement that matches your actual stowage, or let the carrier's DG desk apply it.
A general orientation, not a compliance list for your shipment. Requirements vary with the UN number, the packing group, the country of loading and the carrier. Ticks are kept in this page only and are lost when you close it.
What makes a shipment "dangerous goods"
Far more cargo is regulated than most first-time exporters expect. Paint, adhesives, solvents, aerosols, lithium batteries in or with equipment, pool chemicals, fertiliser, machinery containing fuel, lighters, perfumes and many cleaning products are all regulated for sea transport. The test is not whether the goods feel hazardous; it is whether the substance has an entry in the dangerous goods list carried in the IMDG Code. The supplier's safety data sheet is where you find out, and section 14 of a properly prepared sheet gives the transport information directly.
Getting this wrong is not a paperwork problem. Undeclared dangerous goods are a leading cause of container ship fires, and carriers now screen bookings for suspicious descriptions. A misdeclared container can be rolled, discharged at an intermediate port at your cost, or referred to the authorities, and the liability sits with the shipper.
How the class system is organised
The nine classes group substances by the kind of hazard they present rather than by what they are used for, which is why a class can hold products that seem unrelated. Several classes are split into divisions that behave very differently: within class 4, for instance, a flammable solid, a substance that heats up on its own, and a substance that gives off flammable gas when it gets wet are three separate divisions with three different sets of handling rules. The class number on the label is only the start of the answer; the division and the packing group decide most of what follows.
Packing group indicates the degree of danger within a class: group I is the most dangerous, group III the least. It drives which packaging you may use and, often, how much you may ship under relaxed provisions. Some classes, such as radioactive material and most of class 2, do not use packing groups at all.
Why a dangerous goods booking has to start earlier
A DG booking is not confirmed when the booking system accepts it. The carrier's dangerous goods desk reviews the declaration, checks the goods against its own acceptance policy and the restrictions of every port on the rotation, and then approves or refuses. Allow working days for this, and expect it to take longer where a transhipment port has its own DG rules.
Terminals plan DG stowage before general cargo, so the documentation and gate-in deadlines for a dangerous container are usually earlier than for an ordinary one. Working to the standard cut-off is a common way to miss the vessel.
Carriers maintain their own lists of goods they will not carry at all, or will carry only on certain services, and individual ports and countries add restrictions of their own. A class that moves freely on one trade lane may be refused on another, so confirm acceptance before you commit to a delivery date.
Dangerous goods attract a surcharge that varies by class and trade and can be a significant share of the freight, and some classes also carry handling or stowage charges at the terminal. Price it into your quotation rather than discovering it on the invoice — our landed cost tool has a line for it.
If you are consolidating several products into one container, segregation applies inside the box as well as on the ship, and two of your own products may not be allowed to travel together. Establish that before you buy packaging and book, not while the container is being stuffed.
Lithium batteries deserve their own paragraph
Lithium batteries are the single most common reason an ordinary-looking shipment turns out to be regulated, and the rules differ depending on whether the cells travel alone, packed with equipment, or installed inside it. Each of those is a different UN entry with different marking and documentation. You will normally be asked for a test summary demonstrating the cells meet the required transport testing, and your supplier should be able to provide it; if they cannot, treat that as a warning about the shipment rather than a paperwork delay. Power banks, e-bikes, cordless tools and anything with a rechargeable battery all fall in here.
- Budget the DG surcharge and handling charges in the Landed Cost Estimator.
- Earlier DG cut-offs eat into free time: the Demurrage & Detention Calculator.
- Weight still has to be declared like any other container: the SOLAS VGM Calculator.
- Certification and inspection requirements that often travel with regulated goods: the Trade Standards Directory and the Marine Cargo Insurance & PSI Portal.
Frequently asked questions
Class 1 explosives, class 2 gases, class 3 flammable liquids, class 4 flammable solids and substances that ignite spontaneously or react with water, class 5 oxidizing substances and organic peroxides, class 6 toxic and infectious substances, class 7 radioactive material, class 8 corrosives, and class 9 miscellaneous dangerous substances and articles, which is where lithium batteries and environmentally hazardous substances sit.
They are two of four defined segregation terms, in ascending order of strictness. "Away from" requires the goods to be kept effectively apart but allows them in the same compartment; "separated from" requires them in different compartments or holds; the two stricter terms require an intervening complete compartment, and the strictest requires that intervening compartment to lie lengthways along the ship. The exact separation each demands depends on the stowage location and the type of container, and is set out in the IMDG Code.
At minimum a dangerous goods declaration signed by the shipper and a container packing certificate, which are often combined on one form, supported by the safety data sheet and, for lithium batteries, a test summary. The container itself needs placards and UN numbers on all four sides, plus any additional marks such as the marine pollutant mark. Your carrier will specify its own required set on top of this.
No, and that is deliberate. Segregation between specific classes comes from the IMDG Code's own provisions read together with each UN entry, the stowage location and the container type. It is safety-critical, so we explain what the terms mean without reproducing or approximating the requirements. Take the decision from the Code, your carrier's DG desk or a qualified DG advisor.
No. It is a free independent orientation written by IMPUTIX. The IMDG Code is published by the International Maritime Organization; this page is not published, endorsed or approved by IMO and does not reproduce the Code. Buy the current edition from IMO or an authorised distributor, and note that it is amended on a regular cycle.
General orientation for planning purposes only. It is not regulatory, legal or safety advice, and it must not be used to decide whether goods may be shipped, how they must be packed, or how they must be segregated. The current IMDG Code as implemented by the authorities of the countries concerned, and your carrier's own requirements, govern.