Safety at sea

Danish Maritime Authority

HNS receipt

HNS substances are a number of potentially dangerous and harmful substances that have occurred in connection with the carriage of dangerous and polluting substances by sea.

Who is required to report and when?

Companies that receive HNS substances by sea must every year before 15 March submit information about the quantity of HNS substances received the previous year. This applies in all cases where there is a reporting obligation. The information is forwarded to the IOPC Fund in anonymized form.

The information is of importance to the international entry into force date of the IMO HNS Convention.

When is there an obligation to report?

The reporting obligation applies only to HNS substances carried in bulk (and thus not to packaged goods). Furthermore, the reporting obligation applies only if a company has, within the calendar year concerned, received one or more of the following:

  • liquefied natural gas of light hydrocarbons with methane as the main constituent (LNG)

  • at least 150,000 tons of heavy oil

  • at least 15,000 tons of other HNS substances

Companies that already report heavy oil

A number of companies already report the receipt of heavy oil. They do this in accordance with the regulations on the obligation to report and contribute to the International Oil Pollution Compensation Fund. If the company already reports this, it is not required to make separate reports on HNS substances. This means that the company has no reporting obligation in this case.

Forward reporting form

The Secretariat of the International Oil Pollution Compensation Fund has drawn up a form to be used for companies' reports to the Danish Maritime Authority. Please forward the filled in and signed form to

The Danish Maritime Authority has issued more detailed regulations on the reporting obligation in order no. 1451 of 15 December 2014 on the reporting obligation of receivers of HNS substances carried in bulk by ship.

Carriage of dangerous goods

Bulk carriers or tankers at sea carry the major part of dangerous goods as bulk cargo in liquid or solid form. Another part is carried as packaged, dangerous goods by general cargo ships, container ships, passenger ships and the like.

Packed dangerous goods also include entire truckloads of goods in bulk or tank vehicles carried by sea on board ro-ro ships or passenger ships.

The carriage of dangerous goods by ship is, irrespective of size, regulated by the Danish Maritime Authority and can be divided into the following transport groups:

  • dangerous goods in packaged form

  • solid bulk cargoes

  • liquid chemicals in bulk

  • liquid gas in bulk

  • radiated nuclear fuel, plutonium and high-level radioactive waste.

Ships are generally required to be in possession of documents containing information about the specific cargo before the loading is initiated. Furthermore, in these transport groups there are special requirements for cargo documentation.

Construction and certification of ships

The construction and certification of ships for the carriage of dangerous goods in general

Notice B from the Danish Maritime Authority, chapter II-2, regulations 10 and 19, contains the requirements for the construction and equipment of ships. Ships with a gross tonnage above 500 built after 1 September 1984 and ships with a gross tonnage below 500 built after 1 June 1985 must be fitted with permanent fire-extinguishing systems in their cargo holds in order to carry dangerous goods in packaged form. Furthermore, there are special requirements for the ships' construction and equipment depending on the individual classes of dangerous goods.

The Administration is required to issue a certificate confirming that the ship's construction and equipment meet the requirements for the carriage of dangerous goods. This is valid for 5 years and annual inspections must be performed, which are endorsed onto the certificate. A certificate for the carriage of dangerous goods – with the exception of solid dangerous goods in bulk – is not required for the types of cargoes classified as belonging to classes 6.2 and 7. These two classes are not stated on the certificate, either.

Furthermore, a dangerous goods certificate is not required in connection with the carriage of goods in limited quantities.

Ships constructed before 1 September 1984 and 1 June 1985, respectively, need not meet these requirements, but the packaging, marking and stowage of the goods and training of personnel must be in accordance with the requirements of the IMDG Code.

Dangerous goods in packaged form

Dangerous goods in packaged form on board ships

Dangerous goods in packaged form must be carried in accordance with the provisions of the IMDG Code (International Maritime Dangerous Goods Code).

The IMDG Code contains a list of dangerous substances and requirements for the marking, packaging, separation from other dangerous substances and location on board of the dangerous substance. Packaged dangerous goods are carried by dry cargo carriers, general cargo ships, container ships and ro-ro cargo and passenger ships.

The IMDG Code stipulates requirements for the packaging, marking and stowage of dangerous goods. The goods are divided into nine classes, some of which are divided into sub-groups:

Class 1: Explosive substances and objects (Class 1 is divided into 6 sub-groups). Class 2: Gases. Compressed, liquefied or dissolved under pressure. Class 3: Flammable liquids. Class 4.1: Flammable solids. Class 4.2: Spontaneously combustible solids. Class 4.3: Substances liberating combustible gases when in contact with water. Class 5.1: Oxidizing agents. Class 5.2: Organic peroxides. Class 6.1: Toxic substances. Class 6.2: Biohazards. Class 7: Radioactive substances. Class 8: Corrosive substances. Class 9: Various dangerous substances and objects, i.e. any other substance which experience proves to be - or which turns out to be - of such a dangerous nature that it should be covered by the provisions of this part.

For certain types of ro-ro passenger ships, it is possible – as an alternative to the IMDG Code – to use the "Memorandum of understanding on the carriage of dangerous goods by ro-ro ships in the Baltic Sea area" (also referred to as the "Baltic Sea Memorandum"). This makes it possible for these ro-ro passenger ships to transport trucks carrying dangerous goods without having to change the marking and the transport documents for the dangerous goods from the road transport regulations (ADR) to the sea transport regulations (IMDG Code) within the areas given in the Memorandum of Understanding.

On 1 January 2018, a new Baltic Sea Memorandum entered into force. The Baltic Sea MoU has been completely restructured in order to align it with the equivalent provisions of the IMDG Code. The substantial amendments are limited to the following:

  • clarification as regards the carriage of batteries in bulk (UN 2984, UN 2795, UN 2800 and UN 3028)

  • updating of the provisions on stowage of dangerous goods of classes 2-9

  • the competent authorities' contact data.

Solid bulk cargoes

Bulk cargoes are characterized by solid products consisting of a combination of particles, granulates or large pieces of material that is normally homogeneously structured and which is loaded directly into the hold of a ship without any type of intermediate packaging. Such cargoes must be carried in accordance with the provisions of the IMSBC Code – The International Maritime Solid Bulk Cargoes Code.

The carriage of bulk cargoes may involve a number of risk elements that can be attributed to the dangerous properties of the products carried. They may be products with dangerous properties or products which:

  • can generate combustible, poisonous or harmful vapors during transport

  • are especially heavy and therefore can harm the structure of the ship

  • can "slide" in the hold and thereby affect the stability of the ship

  • change their character during transport, for example sphagnum which can transform from solid to liquid form, etc.

Such cargoes are carried by sea on board bulk carriers, dry cargo carriers, barges, etc.

Dangerous liquid chemicals in bulk

Dangerous, liquid chemicals are chemicals that are listed in chapter 17 of the IBC Code (International Bulk Chemical Code).

This list of chemicals states which type of ship is permitted carry the chemical. There are three types – 1, 2 and 3 – of which type 1 is permitted to carry the most dangerous substances.

Dangerous, liquid chemicals in bulk are carried by chemical tankers that meet the requirements of the IBC Code; however, oil tankers can be designed to transport a few type 3 chemicals; these products can be seen from their certification.

Liquefied gas in bulk

Any type of liquefied gas or other products listed in chapter 19 of the IGC Code (International Gas Carrier Code). This product list subdivides the products into four types – 1G, 2G, 2PG and 3G – where type 1G ships are permitted to carry the most dangerous products. Liquefied gas in bulk is carried on board gas tankers meeting the requirements of the IGC Code.

Radiated nuclear fuel, plutonium and high-level radiated waste

Class 7 material that is also covered by the International Code for the Safe Carriage of Packaged Irradiated Nuclear Fuel, Plutonium and High-Level Radioactive Wastes on board Ships (INF Code).

Ships carrying these cargoes must meet the provisions of Notice B from the Danish Maritime Authority and those of the INF Code. The ships are divided into three classes, where class 3 is the most dangerous one.

The cargoes are carried by dry cargo carriers meeting the requirements of the INF Code and holding an INF certificate.

Carriage of Bauxit and Ammonium Nitrate Based Fertilizer

The IMO has developed a circular (CCC.1/Circ.2/Rev.1) on the carriage of Bauxit which may liquefy. The circular concerns the risk that Bauxit may assume liquid form if carried in bulk. This circular will be incorporated into the IMSBC Code at the next revision.

Furthermore, the IMO has developed a circular (CCC.1/Circ.4) on the carriage of Ammonium Nitrate Based Fertilizer in bulk. Though it is possible to declare Ammonium Nitrate Based Fertilizer as non-hazardous, it can - if carried in bulk and under special circumstances where it undergoes a mechanical or chemical heat reaction - release hazardous gases.

The two circulars: 1.CCC.1/Circ.2/Rev.1, "Carriage of Bauxit which may liquefy" 2.CCC.1/Circ.4, "Carriage of Ammonium Nitrate Based Fertilizer (non-hazardous)"


On 1 July 2016, international regulations became effective requiring the shipper to establish the so-called verified gross mass (VGM) of packed sea containers.

There are two methods for establishing the VGM – either weighing the packed container or adding the individual items in the container to the container's own weight according to a certified method.

The regulations apply to ships that initiate an international voyage after 1 July 2016. The Danish Maritime Authority has – in close cooperation with a number of business organizations – drawn up three short guidelines describing how to implement the regulations.

Written by: Danish Maritime Authority Updated 18.11.2020