Last reviewed 11 July 2019

Richard Masters discusses the consequences of incorrect placarding and marking of CTUs when shipping by sea and how this can be prevented.

Despite the best efforts of the authors of the IMDG Code and ADR, and dangerous goods trainers, some shippers and forwarders persistently hold misconceptions about how to placard and mark dangerous goods containers, and who is responsible for paying for it to be put right if it is wrong. Because of these misconceptions, errors regularly occur, and correcting them takes money and resources.

When presenting containers for shipment by sea, incorrect placarding always creates delays at ports for the delivering road or rail carrier. This is because harbour authorities have a duty under the Dangerous Substances in Harbour Areas Regulations to ensure that all dangerous substances are correctly identified.

Furthermore, in many countries ships are routinely subject to on-board inspections, and if incorrect or missing placards are detected the ship is subject to a fine and the cost of correcting the placards. This may require discharging the container to the quay, correcting the placarding and reloading — an expensive and time-consuming affair called “restowing”.

Dock gate scrutiny helps to avoid this problem, and ensure that incorrect placarding is corrected by the shipper before the containers enter the mechanised port container handling system.

Whose responsibility is it to apply the placards?

The vast majority of sea freight is carried in general purpose freight containers, and one of the most problematic misconceptions is that “it is the haulier’s responsibility to correctly apply the placards”.

In most container operations the shipping line will deliver an empty container by road to the loader’s premises. The driver will be instructed to get out of the vehicle, hand over his vehicle keys and wait until loading has been completed. The container will be closed and sealed by the loader and only then will the driver be permitted back to his vehicle. It is unlikely that the driver will even see what goes into the container.

Under ADR .1(d) the “Loader” is responsible for ensuring that the container displays the correct placards, and in the IMDG Code it is the “Packer” — the party that signs the packing certificate (IMDG The lorry driver is very rarely involved in the loading, so it is unreasonable to consider him responsible for anything relating to it.

It may be useful to think of the container and lorry as separate entities — imagine the container is a parcel with the sender (loader) responsible for the correct stamps (marks and placards) and the lorry as the postman’s van simply delivering your parcel from A to B and handing it over to the next party. Just as you would not expect the postman to be responsible for the stamps, the driver is not responsible for applying the placards to a container; he or she is only responsible for the requirements that apply to the vehicle — such as the ADR orange plate.

The driver uses his or her ADR training to check that the placards match the details on the dangerous goods note, but as we shall see in the examples below, this is not always easy to work out, and it is not the driver’s responsibility. In practical terms, if the driver takes an incorrectly placarded vehicle on the road, he or she is protected from prosecution because while ADR (f) requires the carrier, among other things, to “ascertain that the danger warning labels and markings prescribed for the vehicles have been affixed”, ADR provides that “the carrier may, however, in the case of… (f) rely on information and data made available to him by other participants.”

If concerned, a responsible driver will contact his (or her) employer and request his DGSA to check before departing, but the driver is not ultimately responsible if the placards are incorrect and the container gets held up at the docks as a result.

There are exceptions. Drivers of tankers and tank containers are highly trained and frequently take a leading role in loading and may sign the “filling certificate”, and some specialised vehicle trailer operators require drivers to physically check cargo, and supervise its loading and securing in their vehicles. In these circumstances drivers can justifiably assume joint responsibility as “loaders” or “packers”, but these are outside the scope or mainstream of container shipping.

Points of guidance regarding container placarding and marking

The following general points should be borne in mind.

  1. The purpose of hazard placards

    Hazard placards are applied only to indicate from a distance what type of hazard(s) is inside a CTU, not how many substances, or in what quantity. A CTU with one Class 3 placard could be carrying one Class 3 substance or any number of different Class 3 substances, and some in limited quantity.

  2. Placard both hazard Classes and sub-risks

    A placard is required for each Class (Column 3 in the IMDG DG List) and each sub-risk (Column 4 in the IMDG DG List). In ADR the placarding requirements for both are shown in Column 5 of the DG List.

  3. Application of placards

    When placards and marks have to be applied to containers, always assume they have to be applied to both sides, front and back unless stated otherwise in this article.

  4. Positioning of placards

    There is no “wrong” sequence when applying more than one placard per side, nor a mandatory height up the container.

  5. Placards v. labels

    Placards are the hazard class warning signs that are displayed on the outside of containers, tanks and vehicles and must be at least 250mm x 250mm — hazard labels are designed identically to the placards and are fixed to individual packages, drums, IBCs, bags etc and are at least 100mm x 100mm

  6. Marks v. placards

    The term mark is used for any other item(s) of information that have to be shown regarding the dangerous goods — eg in some cases a UN Number, a diamond-shaped mark indicating that the goods involved are marine pollutants, or the fumigation warning sign.

  7. Adhesion of placards/marks

    Placards/marks must be capable of adhering to CTUs for at least three months immersed in seawater. Placards/marks are generally applied as pressure-sensitive adhesive stickers and in ideal conditions they will perform to this level, but it is surprising how many become detached between the load point and the dock gate. It is impossible to get the pressure-sensitive stickers to adhere to dirty or wet container surfaces. Many experienced loaders use industrial strength aerosol spray adhesive to ensure the stickers stay in place when attached in damp conditions. It is no defence for a loader to claim the stickers were in place when they left their warehouse — many forwarders try to hold the haulier responsible for costs for replacing detached placards, but in terms of IMDG responsibilities, the “three months under water” rule applies and the charges will always be passed back to the loader.

CTUs carrying packages

The following examples cover placarding and marking requirements of all the common combinations of dangerous substances (including dangerous articles) applicable to containers loaded for sea from inland load points.


For the carriage of dangerous goods in excepted quantity packages there is no requirement for any marking of the CTU.

Example 1: Single substance, less than 4000kg, no sub-risk

The requirement is for a single placard, in this example a Class 3 substance. There may be any quantity of other non-hazardous goods in the container — this will not affect the placarding requirements.

Example 2: Single substance, more than 4000kg, no sub-risks

The requirement is for a Class placard as in Example 1, but in addition, when there is more than 4000kg of a single dangerous substance, the UN Number should be added all round, in this case UN 1277. There are two ways of displaying the UN Number (see below).

There may be any quantity of other non-hazardous goods in the container — this will not affect the placarding requirements.


If the substance had a sub-risk, the sub-risk placard would also be displayed on all four sides.

Example 3: Two hazard Classes

A freight container loaded with two different hazard Classes must display placards for both Classes an all sides. The Class 3 and 6.1 placards shown here could represent various combinations:

  • a Class 3* substance that has a Class 6.1 sub-risk, or

  • a Class 6.1 substance that has a Class 3 sub-risk, or

  • a Class 3 substance loaded with a different Class 6.1 substance.

There is no way of telling from the placards which of the above applies — the documentation has to be consulted.


*If more than 4000kg of this single dangerous good then the UN number marking, as shown on example 2, is also required.

Example 4: Three hazard Classes

A freight container loaded with three hazard Classes requires three placards all round. The Class 3, 6.1 and 8 placards shown here could represent any of the following hazard combinations.

  • A Class 3 substance* that has a Class 6.1 sub-risk and a Class 8 substance.

  • A Class 3 substance that has a Class 8 sub-risk and a Class 6.1 substance.

  • A Class 8 substance that has a Class 6.1 sub-risk and a Class 3 substance.

  • A Class 8 substance that has a Class 3 sub-risk and a Class 6.1 substance.

  • A Class 6.1 substance that has a Class 8 sub-risk and a Class 3 substance.

  • A Class 6.1 substance that has a Class 3 sub-risk and a Class 8 substance.

  • A Class 3 substance, a Class 6.1 substance and a Class 8 substance.


*If there is more than 4000kg of this single dangerous good then the UN number marking, as shown on example 2, is also required.

Example 5: Single Class or multiple Classes all in Limited Quantities

If all the dangerous goods are in limited quantity (LQ) packages only a single LQ mark all round is required, regardless of how many Classes of LQ are in the container.

The amount of dangerous goods in limited quantities that can be packed into a CTU is restricted only by the maximum allowable cargo weight of the container.


If the dangerous goods are also classified as marine pollutants, see Example 10.

Example 6: Dangerous goods loaded together with dangerous goods in Limited Quantities

If dangerous goods in limited quantities are loaded into a CTU with dangerous goods that are not in limited quantities, then the limited quantity mark is not shown, but the placards for the Classes and sub-risks of dangerous goods not in limited quantities are shown.

In this example there are goods of Class 3, not in limited quantities, and if there were other dangerous goods in limited quantities* then the limited quantities mark must not be shown. The Class 3 hazard in standard packaging is considered to outweigh the hazard of any quantity of dangerous goods of any Class in any quantity.


*However, if the LQ goods are also classified as Marine Pollutants (see following), then the CTU shall be placarded/marked as Example 7 below.

Marine Pollutants

“Marine Pollutant” is a supplementary classification requirement that applies only to sea transport.

A substance classified into any Class may be also considered a marine pollutant if it meets the criteria in IMDG Chapter 2.10 of being harmful to the marine environment.

Since 1 January 2014 the criteria for determination as a Marine Pollutant have been the same as the ADR/RID/ADN and ICAO (IATA) Classification as an Environmentally Hazardous Substance (EHS), being based on the UN’s Globally Harmonised System of Classification and Labelling of Chemicals (known in short as GHS or Purple Book) (Rev 3 and later).

This is a self-classification requirement under all modes. However, certain substances (not mixtures) considered by IMO to be Marine Pollutants are positively identified by a “P” mark in the Code. These must be considered as MPs unless the consignor can get acceptance from the Competent Authority (CA) that the substance does not meet the criteria. This is not known to have happened so far. Were it to occur it is expected that the CA would propose the removal of the “P” mark from the Code.

However, IMDG Code and ICAO (IATA), but strangely not ADR/RID/ADN, also permit the UN3077 Environmentally hazardous substance, solid, n.o.s. and UN3082 Environmentally hazardous substance, liquid, n.o.s. entries to be used for goods that are wastes that are not otherwise dangerous (ie are not classifiable in any other class, or as MPs), but which are subject to control under the Basle Convention on the Control of Transboundary Movements of Hazardous Waste and their Disposal.

Example 7: Class 3 and also MP

In this example a Class 3 substance has been classified also as a marine pollutant, and the marine pollutant mark has been applied.

Example 8: UN 3077 & 3082 that are also marine pollutants

For a sea journey the following rules must be applied: If a substance is described on the dangerous goods transport document as UN3077 or UN3082 and as a “Marine Pollutant”, then the marine pollutant/environmentally hazardous mark must be shown alongside the Class 9 placard.

Example 9: UN30077 and UN3082 that are not also MP

These require Class 9 placards only, and no MP mark, even though the proper shipping name commences with “Environmentally Hazardous Substances”. These goods will not be dangerous goods for ADR/RID/ADN (see above).

Example 10: Limited quantities that are also marine pollutants

In cases where all the dangerous goods are in limited quantities and some or all are also declared as marine pollutants, the container should display the limited quantities mark and the marine pollutant mark. Under ADR/RID/ADN there is no requirement for any marking of the CTU.

Marking tank containers and dry bulk containers

Tank containers are required to be marked on all four sides with the Class (and any sub-risk) placards in the same way as for containers.

In addition:

  • the UN Number is also required on all four sides (IMDG, and

  • the Proper Shipping Name is required on at least both sides of the tank (IMDG

The lettering of the PSN shall be at least 65mm high.

Containers shipped “under fumigation”

Containers are frequently shipped under live fumigation to preserve the cargo, or to sterilise both the cargo and the timber packing to comply with phytosanitary regulations such as UN 3359, Class 9. The fumigation mark shown below is required to be shown on the doors only, and the Class 9 placard is not required. Placards should be applied all round for other hazard Classes in the normal way (IMDG

IMDG Code exceptions — when placards/marks are not required

There a few products for which placards may not be required on CTUs, provided certain provisions are met to enhance safety. These are indicated in Column 6 of the Special Provisions of the IMDG Code. Some common examples are:

  • vehicles, boats and equipment powered by internal combustion engines that have the batteries isolated and fuel tanks drained (IMDG SP 961)

  • non-spillable batteries with the terminals isolated (IMDG SP 238)

  • lithium batteries (various types) that meet certain design criteria (IMDG SP 188).