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Road transportation

Packaged goods transport labelling

Different regimes are used to placard and label dangerous goods transported in packages.

Following classification, the manufacturer or importer will be able to produce an appropriate label for the substance. For transport purposes, this label will include:

  • The designation of the product or its proper shipping name (PSN); this is the official description listed in the regulations for a particular UN number
  • The UN number
  • Appropriate hazard warning symbols

If a product is not specifically listed in the Regulations, or the hazardous properties and emergency response procedures for a solution or mixture differ significantly from those of the pure substance, then one of the generic (N.O.S.) entries must be used. In such cases, the PSN must be supplemented with the technical name of the goods. The technical name should be a recognised chemical name for the substance or substances which caused the product to be classified as hazardous. Normally not more than two ingredients are named (for example, gasoline and carbon tetrachloride mixture UN 1992 flammable liquid, toxic, N.O.S.  or trimethyl gallium UN 2003 metal alkyl, N.O.S.).

Image 8 Transportation label for packaged methanol

There are different requirements for labelling products for supply and use, which are covered separately. However, for some containers the labels for transport and supply can be combined.

Image 9 A combined label for transport and supply


Combination packages

Packaged goods are usually transported in a combination package consisting of inner packages of a size intended for supply (usage), packed into an outer box convenient for transport.

Packages for transporting hazardous goods are required to be fit for purpose and be tested and marked with a UN symbol to show this (for example: 4G/Y25/S/03/GB/PRL271). For further information regarding packaging see HSE Packaging.

The inner package will be labelled for supply purposes, while the outer package will be labelled for carriage. Because the regulations for transport and supply of hazardous goods cover different hazards, the labels that have to be provided on each layer of the package can be different for each.

This can cause some confusion, particularly where the inner containers of a package may be labelled as toxic because of their potential to cause adverse effects with long-term exposure, while the outer containers may not be labelled at all because the product does not have an effect with short-term exposure.

Image 10 Combination package



ADR hazard identification numbers (HIN) or ‘Kemler Code’

The hazard identification number consists of two or three figures indicating the following hazards:

Table 22 Hazard identification numbers
No. Hazard
2 Emission of gas due to pressure or chemical reaction
3 Flammability of liquids (vapours) and gases or self-heating liquid
4 Flammability of solids or self-heating solid
5 Oxidising (fire-intensifying) effect
6 Toxicity
7 Radioactivity
8 Corrosivity
9 Risk of spontaneous violent reaction

Duplication of a figure (e.g. 55) indicates an intensification of that particular hazard.

Where the hazard associated with a substance can be adequately indicated by a single figure, this is followed by a zero.

A hazard identification number prefixed by letter X indicates that the substance will react dangerously with water.

Table 23 below shows the meanings of hazard identification number combinations:

(*Water must not be used except by approval of experts

Table 23 Hazard identification number meanings
Number Meaning
20 Asphyxiant gas or gas with no subsidiary risk
22 Refrigerated liquefied gas, asphyxiant
223 Refrigerated liquefied gas, flammable
225 Refrigerated liquefied gas, oxidising (fire intensifying)
23 Flammable gas
238 Gas, flammable corrosive
239 Flammable gas, which can spontaneously lead to violent reaction
25 Oxidising (fire-intensifying) gas
26 Toxic gas
263 Toxic gas, flammable
265 Toxic gas, oxidising (fire-intensifying)
268 Toxic gas, corrosive
28 Gas, corrosive
285 Gas, corrosive, oxidisingFlammable liquid that reacts with water, emitting 30flammable gases
30 Flammable liquid (flash-point between 23°C and 60°C inclusive) or flammable liquid or solid in the molten state with a flash point above 60°C, heated to a temperature equal to or above its flash point, or self-heating liquid
323 Flammable liquid that reacts with water, emitting flammable gases
X323 Flammable liquid that reacts dangerously with water, emitting flammable gases
33 Highly flammable liquid (flash point below 23°C)
333 Pyrophoric liquid
X333 Pyrophoric liquid, which reacts dangerously with water*
336 Highly flammable liquid, toxic
338 Highly flammable liquid, corrosive
X338 Highly flammable liquid, corrosive, which reacts dangerously with water*
339 Highly flammable liquid that can spontaneously lead to violent reaction
36 Flammable liquid (flash point between 23°C and 60°C inclusive), slightly toxic or self-heating liquid toxic
362 Flammable liquid, toxic, which reacts with water, emitting flammable gases
X362 Flammable liquid, toxic, which reacts dangerously with water, emitting flammable gases*
368 Flammable liquid, toxic, corrosive
38 Flammable liquid (flash point between 23°C and 60°C inclusive), slightly corrosive or self-heating liquid, corrosive
382 Flammable liquid, corrosive, which reacts with water, emitting flammable gases
X382 Flammable liquid, corrosive, which reacts dangerously with water, emitting flammable gases*
39 Flammable liquid, which can spontaneously lead to violent reaction
40 Flammable solid, or self-reactive substance, or self-heating substance
423 Solid that reacts with water, emitting flammable gas, or flammable solid which reacts with water, emitting flammable gases or self-heating solid which reacts with water, emitting flammable gases*
X423 Solid that reacts dangerously with water, emitting flammable gases, or flammable solid that reacts dangerously with water, emitting flammable gases, or self-heating solid that reacts dangerously with water, emitting flammable gaseFlammable solid, in the molten state at an elevated temperatures*
43 Spontaneously flammable (pyrophoric) solid
X432 Spontaneously flammable (pyrophoric) solid that reacts dangerously with water, emitting flammable gases*
44 Flammable solid, in the molten state at an elevated temperature
446 Flammable solid, toxic in the molten state, at an elevated temperature
46 Flammable or self-heating solid, toxic
462 Toxic solid that reacts with water, emitting flammable gases
X462 Solid that reacts dangerously with water, emitting toxic gases*
48 Flammable or self-heating solid, corrosive
482 Corrosive solid that reacts with water, emitting corrosive gases
X482 Solid that reacts dangerously with water, emitting corrosive gases*
50 Oxidising (fire-intensifying) substance
539 Flammable organic peroxide
55 Strongly oxidising (fire-intensifying) substance
556 Strongly oxidising (fire-intensifying) substance, toxic
558 Strongly oxidising (fire-intensifying) substance, corrosive
559 Strongly oxidising (fire-intensifying) substance, which can spontaneously lead to violent reaction
56 Oxidising substance (fire-intensifying), toxic
568 Oxidising substance (fire-intensifying), toxic, corrosive
58 Oxidising substance (fire-intensifying), corrosive
59 Oxidising substance (fire-intensifying) that can spontaneously lead to violent reaction
60 Toxic or slightly toxic substance
606 Infectious substance
623 Toxic liquid, which reacts with water, emitting flammable gases
63 Toxic substance, flammable (flash point between 23°C and 60°C inclusive)
638 Toxic substance, flammable (flash point between 23°C and 60°C inclusive), corrosive
639 Toxic substance, flammable (flash point not above 60°C inclusive), which can spontaneously lead to violent reaction
64 Toxic solid, flammable or self-heating
642 Toxic solid, which reacts with water, emitting flammable gases
65 Toxic substance, oxidising (fire-intensifying)
66 Highly toxic substance
663 Highly toxic substance, flammable (flash-point not above 60°C inclusive)
664 Highly toxic substance, flammable or self-heating
665 Highly toxic substance, oxidising (fire-intensifying)
668 Highly toxic substance, corrosive
669 Highly toxic substance that can spontaneously lead to a violent reaction
68 Toxic substance, corrosive
69 Toxic or slightly toxic substance, which can spontaneously lead to a violent reaction
70 Radioactive material
78 Radioactive material, corrosive
80 Corrosive or slightly corrosive substance
X80 Corrosive or slightly corrosive substance, which reacts dangerously with water*
823 Corrosive liquid which reacts with water, emitting flammable gases
83 Corrosive or slightly corrosive substance, flammable (flash point between 23°C and 60°C inclusive)
X83 Corrosive or slightly corrosive substance, flammable (flash point between 23°C and 60°C inclusive), which reacts dangerously with water*
839 Corrosive or slightly corrosive substance, flammable (flash point between 23°C and 60°C inclusive), which can spontaneously lead to violent reaction
X839 Corrosive or slightly corrosive substance, flammable (flash point between 23°C and 60°C inclusive), which can spontaneously lead to violent reaction and which reacts dangerously with water*
84 Corrosive solid, flammable or self-heating
842 Corrosive solid which reacts with water, emitting flammable gases
85 Corrosive or slightly corrosive substance, oxidising (fire-intensifying)
856 Corrosive or slightly corrosive substance, oxidising (fire-intensifying) and toxic
86 Corrosive or slightly corrosive substance, toxic
88 Highly-corrosive substance
X88 Highly-corrosive substance, which reacts dangerously with water*
883 Highly-corrosive substance, flammable (flash-point between 23°C and 60°C inclusive)
884 Highly-corrosive solid, flammable or self-heating
885 Highly-corrosive substance, oxidising (fire-intensifying)
886 Highly-corrosive substance, toxic
X886 Highly-corrosive substance, toxic, which reacts dangerously with water*
89 Corrosive or slightly-corrosive substance, which can spontaneously lead to a violent reaction
90 Environmentally hazardous substance; miscellaneous dangerous substances
99 Miscellaneous dangerous substance carried at an elevated temperature

UK bulk vehicle placarding

Image 19 UK Hazchem hazard warning panel - single bulk load


Single bulk load              

Image 19 above shows the signage for a bulk single load (in excess of three cubic metres).  The detailed signage will be on the sides and rear of the vehicle.

Image 20 Single load in packages in a freight container

Image 20 above shows signage for a vehicle carrying dangerous goods in packages in a demountable freight container. In addition to orange panels on the front and rear of the vehicle, all sides of the container will have the standard warning symbols, according to the hazards posed by the load.

Image 21 Single load tanker

The image above shows a single load tanker. Note the variations in showing the key information.

Image 22 Multi load tanker

Image 22 above shows the signage for a multi load tanker. The main placard will state multi-load but the hazard symbol(s) will show the hazard(s) of the load. Each individual compartment of the tanker will have its own sign giving the UN number for the substance and the hazard symbol denoting its specific hazard.

European ADR vehicle bulk placarding

Image 23 Single bulk load showing ADR markings for a bulk single load

European ADR tanker or tank placarding

Image 24 Single load tanker showing ADR markings


Single load tanker

For tank vehicles carrying only one substance, as shown above, the identification numbers can be shown on the orange plates at the front and rear of the vehicle. Hazard warning symbols are located on each side of the vehicle and at the rear (as indicated).

Image 25 Bulk load tanker
Image 26 Tank vehicle carrying a multi load will display signage as shown above

Tank container

Vehicles carrying tank containers must display orange plates on each side of the tank, or tank compartments, giving hazard and substance identification numbers. A blank plate is displayed at the front and rear. Hazard warning symbols are located on each side of the compartment adjacent to each ADR placard.

Tank containers must have the identification numbers on the tank itself to remain in sight when the tank is offloaded from the vehicle.

Elevated temperature marking

Tank vehicles, tank containers, portable tanks, special vehicles or containers or specially-equipped vehicles or containers carrying elevated temperature substances are required under ADR to display an elevated temperature mark on both sides and at the rear for vehicles, and on both sides and at each end for  containers, tank-containers and portable tanks. Image 27 below shows the elevated temperature marking displayed according to ADR,

Image 27 Elevated temperature marking

Environmentally hazardous substances marking

When  required  to  be  displayed  in  accordance  with  the  provisions  of ADR, containers, tank-containers, portable tanks and vehicles containing certain environmentally hazardous substances are to be marked  with the environmentally hazardous substance mark shown below.

Image 28 Environmentally hazardous substances marking

Switch-loading of petrol and distillate fuels

Switch-loading is the terminology used to describe the practice of loading a distillate fuel (e.g. diesel or gas oil), into a tank compartment that has previously contained petrol. Switch-loading can also be practiced between petrol and kerosene but this practice is normally discouraged because of the risk of residual petrol (liquid or vapour) lowering the flash point of the kerosene.

In the UK the practice of switch-loading road tankers is very common, undertaken by perhaps as many as 95% of petrol/distillate fuel tankers to minimise unnecessary journeys (e.g. by discharging one load and returning with another). Compartments of tankers that have been switch-loaded will not only contain the liquid distillate product but also an amount of petrol vapour remaining from the previous load or loads.

Road tankers that transport petrol are designed and constructed for bottom loading with vapour recovery and in addition to the compartment ullage spaces, petrol vapour will be retained in the associated vapour manifold and pipework, together with small amounts of petrol in other associated pieces of equipment.

Distillate fuels have a greater density than petrol and in many cases a nominal full load of distillate will require a tanker to run with an empty or partially filled compartment, to ensure that the vehicle does not exceed its maximum authorised mass on the road.

Large volumes of petrol vapour will be retained in the empty and/or partially-filled compartments of a tanker carrying distillates in which petrol has been previously loaded. Even in compartments not previously loaded with petrol there is a risk that vapour will be present. This is due to the inter-compartment connection afforded by the vapour manifold and the vapour transfer valves, all of which are open during the bottom loading process. It is possible that a tanker may arrive at a site with a full load of diesel and leave with a full load of petrol vapour.

Where a mixed load of liquid products comprises petrol, diesel, kerosene or aviation fuels the tanker will be marked with the UN number of the product with the greatest hazard i.e. the lowest flashpoint. In the case of empty, uncleaned tanks, the tanker is marked as if it still contained the original product. However, there are no specific marking provisions where the transport of a single substance with the residual vapour of a product with a greater hazard (lower flashpoint) is undertaken, even though this may present a similar hazard to that of an empty uncleaned tanker.

Under the current regulations, a compartment that was previously filled with petrol and then refilled with diesel and subsequently emptied of the diesel would have to be marked UN 1202 (diesel) to reflect the last load in the uncleaned tank, but in fact could be filled with petrol vapour.

These hazards are recognised by the petroleum industry and as a result it has become widespread practice in the UK for road tanker operators to retain the petrol marking (UN 1203) on tankers for a number of full loads of diesel or gas oil (UN 1202) after carrying petrol, to reflect the presence of the retained petrol vapour and the greater danger this may pose.

Actions for fire and rescue services

Fire and rescue services should be aware that, when dealing with incidents involving petrol/distillate tankers, any of the tank compartments may contain mixtures of distillate and petrol vapour. Therefore, all the tanks should be treated as if they contained petrol vapour until information to the contrary is obtained.

This also means that tanks may contain diesel/gas oil as the main load but may still be marked as petrol to better reflect the greater danger from any residual petrol vapours.

The emergency action code (EAC) for all such tankers should therefore be taken to be 3YE (indicating a possible public safety hazard beyond the immediate area of the incident) even though the emergency action code for the distillates will be 3Y and some tankers may still be marked as such.

As there are no movements of petrol/distillate tankers to and from Europe this will not be an issue for non-UK registered tankers (i.e. those marked with ADR hazardous identification numbers).

Registration, evaluation, authorisation and restriction of chemicals (REACH) Regulations

Registration, evaluation, authorisation and restriction of chemicals (REACH) is a European Union regulatory framework for chemicals, which came into force on 1 June 2007. REACH has several aims and puts greater responsibility on industry to manage the risks from chemicals and to provide safety information that will be passed down the supply chain.

REACH will require some 30,000 chemical substances to be registered over a period of 11 years, excluding the following;

  • Radioactive substances
  • Substances under customs supervision
  • The transport of substances
  • Non-isolated intermediates
  • Waste
  • Some naturally occurring low-hazard substances

The registration process requires anyone manufacturing more than one tonne per year of these substances within the EU, or importing this amount into the EU, to generate data for all chemicals produced or imported, whether on their own or in one or more preparations. This information must be registered with the European Chemicals Agency. The registrants must also identify appropriate risk management measures and communicate them to the users.

In addition, REACH will allow the further evaluation of substances where there are grounds for concern and foresees an authorisation system for the use of substances of very high concern. This applies to substances that cause cancer, infertility, genetic mutations or birth defects, and to those that are persistent and accumulate in the environment. The authorisation system will require companies to switch progressively to safer alternatives where a suitable alternative exists. All applications for an authorisation need to include an analysis of alternatives and a substitution plan where a suitable alternative exists. Current use restrictions will remain under the REACH system.

Rail transportation

All classes of hazardous substances are carried on the UK rail network (except in Northern Ireland).  The carriage of dangerous goods regulations apply to rail transport, with detailed guidance coming from the Carriage of Dangerous Goods Manual (HSE).

The only exceptions to the regulations are:

  • Substances carried with the sole purpose of being used on, or by, the train (e.g. fuel)
  • Radioactive materials; these have their own Regulations (Packaging Labelling and Carriage of Radioactive Material by Rail Regulations)

The regulations require that sufficient information is supplied with the load to ensure that all involved with the transportation process can:

  • Identify what is being carried
  • Be aware of the potential hazards
  • In the case of the fire and rescue service, respond quickly and efficiently

The information is supplied to the train operator and the rail infrastructure controller, therefore if there is an incident and the information cannot be obtained from the train driver, it can be obtained from the operator. 

The information given includes:

  • Designation and classification of the dangerous goods
  • UN number
  • Packaging group
  • Compatibility and division for explosives
  • Consignor and consignee details
  • Specialist advice
  • Mass and volume of the:
    • Package
    • Tank, tank container, or tank wagon
    • Bulk load in container or wagon
    • Total consignment.

Containers, tank container, tank wagons and wagons must display relevant signage related to their contents, using the UK Hazchem system for UK-only journeys or the RID marking provisions for international journeys (these mirror those of ADR for road vehicles), as shown above.

Total operations processing system (TOPS)

The total operations processing system (TOPS) is a computerised system that enables Network Rail to keep a constant check on the position and availability of every rail vehicle on their system and provide specific information of the various loads that are being hauled.

It consists of a central computer system connected to regional control offices, marshalling yards and depots throughout the country. The system is based on a main computer, which is linked to input points at area freight offices throughout Network Rail.

From these control centres, details of all the wagon and freight details, whether they are loaded or unloaded, freight train movements and type of traffic conveyed are fed into the computer. On request by an incident commander via fire service control and Network Rail control office can obtain any specific information from the system, on any wagon or freight train and its cargo. Each wagon is clearly marked with an individual identification number on its side. This number will be recorded on the TOPS computer so that information on the load can be made readily available for operational staff in the event of an incident.

Image 29 Location of identification numbers and hazard warning plates on wagon


Additional tank wagon identification schemes

Tank wagons carrying certain classes of dangerous goods can be identified by specific colour schemes.  For example, tank wagons carrying Liquefied petroleum gas (LPG) will have a white barrel with a horizontal orange stripe round the barrel at mid height. Tank wagons carrying flammable liquids are painted dove grey and the sole bars are painted signal red (sole bars are the two horizontal metal bars on which the bottom of the tank rests).

In addition, all wagons containing dangerous goods will have a Network Rail dangerous wagon label displayed on each side. This label indicates the class of substance being carried and the principal hazard that could be encountered. Containers that are hauled by rail are exempt from being labelled in this manner.

The emergency code for the label consists of a six digit number. The first four numbers are the substance identification number for the substance carried or the class, division and compatibility group in the case of explosives. The remaining two letters are referred to as the alpha code. This code has been allocated to firms and enables Network Rail to ascertain the telephone number that should be used to request specialist assistance in the event of an emergency.

Image 30 Example of tank wagon designed to carry LPG

Information available from the rail vehicle crew

The rail vehicle crew holds information on the specific details of each wagon and the details of their individual loads. This is recorded on an information sheet known as the consist. It will contain the following information:

  • Position of every wagon from front to rear
  • Train identity number
  • Locomotive identity number
  • Wagon numbers
  • Dangerous goods emergency codes
  • UN number plus specialist advice contact code

It would be advisable for the incident commander to obtain the consist as it will provide immediate information on the type of loads being carried and give interim guidance on a course of action to follow until further information is secured either from TOPS or from a designated specialist adviser.

The 2018 Network Statement: Network Rail gives further information on Exceptional Transports and Dangerous Goods.

Irradiated fuel flasks

If an incident involving an irradiated fuel flask occurs, NAIR will be activated immediately. However, some operational priorities need to be considered whilst the NAIR scheme is instigated. For further information see National Operational Guidance: Health hazards.

Image 31 Irradiated fuel transport flask being loaded onto a train

Air transportation

Unlike road and rail transportation of hazardous materials, all air transport is classed as international and therefore is governed by international regulations and agreements.

The worldwide system used to control the transportation of dangerous goods by air is based on the same United Nation’s Emergency Response Guidebook (ERG) requirements placed on all other modes of transport. International requirements for the safe air transportation of radioactive material also relate to UN standards.  Because of the particular nature of air transportation, restrictions on the type and quantities of dangerous goods transported are strictly enforced.

Worldwide harmonisation

Worldwide harmonisation of the transportation of dangerous goods by air is overseen by an agency of the UN. The principles of the international requirements are contained in the International Civil Aviation Organisation (ICAO) technical instructions and include:

  • Classification
  • Identification (marking, labelling and documentation)
  • Acceptability for air transport
  • Packaging and packing
  • Loading and stowage
  • Information
  • Training
  • Reporting of incidents and accidents
  • Inspection and investigation

International agreement

The Convention on International Civil Aviation (Chicago Convention) and its annexes set out the international standards and principles for air transportation throughout the world. Annex 18 to the Convention contains the principles applied to dangerous goods. They require that:

  • States ensure compliance with the technical instructions
  • There must be inspection surveillance and enforcement procedures
  • Dangerous goods accidents and incidents must be reported
  • Dangerous goods accidents and incidents must be investigated
  • ICAO technical instructions and IATA dangerous goods regulations
  • The ICAO technical instructions are produced in English and are the source of the legal rules.

The International Aviation Transportation Association (IATA), the aviation trade organisation, publishes a set of Dangerous Goods Regulations that incorporate the ICAO technical instructions. The only real difference between the two documents is the order of the information, although the IATA document is more restrictive than the technical instructions. The IATA document is a field document and is more commonly referred to in aviation circles.

UK law

The UK’s legal obligations under the Chicago Convention are fulfilled by the following:

The Air Navigation Order 2016, which permits the making of regulations to control the carriage of dangerous goods by air.

The Air Navigation (Dangerous Goods) Regulations 2002 (As amended 2017) that contain detailed requirements and refer to the need for airlines to comply with the latest edition of the ICAO technical instructions.

The Air Navigation (Dangerous Goods) Regulations apply to:

  • Shippers
  • Freight agents
  • Handling agents
  • Couriers
  • The Post Office
  • Passengers
  • Operators

The regulations require the above operators and users to comply with the technical instructions and to have permission to carry dangerous goods from the Civil Aviation Authority (CAA).

Cargo aircraft

These aircraft are designed or modified for the carriage of cargo only, both in the under-floor hold and on the main deck.  Aircraft specifically designed to carry cargo may have nose-opening or tail-opening cargo doors to allow loading of large or specialist cargoes. Other cargo aircraft have large main-cabin freight doors, usually positioned aft of the nose area on the port side.

Dangerous goods can be carried on cargo aircraft either in the under-floor holds or on the main deck.  Those in the under-floor holds will be in passenger aircraft quantities, whereas those on the main deck will usually be cargo aircraft only items.

Passenger aircraft with under-floor holds (only)

These aircraft (examples include the Boeing 737, 747 and Airbus 3 series) are designed primarily for carrying passengers. Cargo (and baggage) will be carried in holds that are below the main deck (under floor). The introduction of wide-bodied passenger aircraft means there is a great deal of capacity in the under-floor holds for carrying cargo. Dangerous goods may be carried in the under-floor holds in passenger aircraft in limited quantities.

Passenger aircraft with holds on the same deck as passengers (combi-aircraft)

These aircraft have also been designed primarily for carrying passengers.  There are two types:

  • The holds are on the same deck as the passengers
  • The holds are on the same deck as the passengers and there are also under-floor holds

In aircraft with holds on the same deck as the passengers, the holds may be little more than areas of the cabin separated from the passengers by curtains. In others they may be surrounded by sealed bulkheads with access from outside the aircraft only or through doors in the cabin that are kept locked in flight. Aircraft with holds on the same deck as passengers have come to be known as combi-aircraft.

Dangerous goods in passenger aircraft quantities may be carried on combi-aircraft in under-floor holds and on the main deck holds. When dangerous goods are carried, the hold must be totally separated from passengers by a bulkhead. Some low-hazard dangerous goods (i.e. those that would not lead to a serious safety or health problem in the event of a leakage) may be carried in the main deck cargo hold on other types of combi-aircraft, with approval from the Civil Aviation Authority.

Convertible aircraft (quick change aircraft)

A number of aircraft are designed to be converted quickly so that during the day they can carry passengers and at night carry cargo; they are known as quick change (QC) aircraft. Dangerous goods can be carried on QC aircraft as permitted for passenger or cargo aircraft, depending on the configuration at the time

Principles of safe transportation of dangerous goods by air

According to the hazard posed by the substance, dangerous goods may be:

  • Carried on passenger and or cargo aircraft
  • Restricted to cargo aircraft only
  • Forbidden on both passenger and cargo aircraft (but exemption to carry may be possible)
  • Totally forbidden in all circumstances
  • Packaged: no bulk transportation
  • Carried in limited quantities per package for passengers and cargo

Dangerous goods integral to the aircraft

Many systems and items of equipment on board an aircraft are considered to be hazardous materials; these include:

  • Aircraft equipment:
  • Life rafts, aerosols
  • Fire extinguishers
  • Dry ice
  • Batteries
  • Alcohol
  • Oxygen generators
  • Perfumes and colognes
  • Fuel, matches and lighters
  • Passenger baggage

Packaging for transport by air

The requirements for packaging are similar to those required by ADR and the Chemicals (Hazard Information and Packaging for Supply) Regulations, except that packages must also take into account:

  • Temperature variations
  • Pressure differences
  • Vibration

Packages are therefore required to undergo the following tests:

  • Drop test
  • Stacking test
  • Leak-proof test (drums only)
  • Hydraulic (pressure) test (drums only)

Marking and labelling

Packaged goods are marked and labelled in accordance with UN recommendations. Both primary and secondary hazard symbols are displayed if appropriate.

Where goods are designated as being excluded from passenger aircraft, an aircraft-specific CAO (cargo aircraft only) orange label must be displayed.

Image 32 Cargo aircraft-only label

Shipper’s declaration

All dangerous goods must be accompanied by a shipper’s declaration. The shipper’s declaration for dangerous goods can be distinguished from other flight documents by the red and white hatching on each side of the document. The declaration should contain the following information:

  • Proper shipping name
  • UN number
  • UN class, division and subsidiary risk(s)
  • Packing group (if applicable)
  • Packing instructions and type of packaging
  • Net quantity and number of packages
  • Radioactive materials must additionally carry the:
    • Name or symbol of radionuclide
    • Activity
    • Package category and transport index

The image below shows an example of the shipper’s declaration, which is produced by the shipper. There should be one copy at the originating point with one other travelling with the dangerous goods.

Image 33 Shipper's declaration

Notification to the commander (NOTOC)

A special load form must be given to the commander of the aircraft, identifying the dangerous goods that have been placed on board in the cargo and where they have been loaded. This form is known as a notification to the commander (NOTOC) and must be on the aircraft in the possession of the commander. There should also be a copy of the NOTOC at the loading airport although, unlike the commanders copy, this is not a legal requirement.

Loading of dangerous goods

  • Packaged dangerous goods could be loaded into aircraft:
  • As individual packages
  • On pallets
  • Within transport loading units (known as unit load devices (ULD))


Image 34 Example of an air transport unit load device

Image 34 above illustrates a typical unit load device (ULD). This refers to any type of container with an integral pallet, or an aircraft pallet, whether or not owned by an IATA member, and whether or not considered to be aircraft-equipped. These units interface directly with an aircraft loading and restraint system. Such units become an integral part of the aircraft structure when loaded.

If the labels on packages are not visible when they are on pallets or in ULDs, a red hatched tag showing the hazard classes present must be displayed on the outside of the pallet or ULD. The cargo aircraft only (CAO) label must also be displayed or be visible where appropriate.

Loading restrictions

Packaged dangerous goods:

  • Must not be stowed in the passenger cabin or on the flight deck
  • Must not be on passenger aircraft if labelled 'cargo aircraft only' (CAO)
  • Cargo aircraft only (CAO) packages must be accessible in flight
  • Packages of liquids with orientation arrows must be upright
  • Packages must be secured to prevent movement
  • Damaged packages must not be loaded
  • Incompatible dangerous goods must not be stowed to allow interaction
  • Most explosives must be segregated from other dangerous goods
  • Some types of radioactive materials must be separated from persons
  • Magnetized material must be loaded so that the compass cannot be affected.


Incidents can be categorized into those:

  • On the ground
  • Occurring during flight

If an incident involving dangerous goods occurs during the flight, the aircraft’s commander will refer to Emergency Response Guidance for Aircraft Incidents Involving Dangerous Goods. This publication is produced by ICOA and provides emergency response details including an in-flight checklist for each dangerous substance category hazard. For incidents on the ground, the airport fire service will usually deal with the incident, supported by the airport’s local fire and rescue service.

As a requirement of Annex 18 to the Chicago Convention, all incidents must be investigated.

See National Operational Guidance: Transport.

Maritime transportation

Much of the cargo transported by sea may be classed as dangerous. Incidents involving dangerous substances at sea can be divided into two main areas:

  • Incidents off-shore
  • Incidents in harbour

The main difference between these two types of incident is that for an incident located in a harbour, the hazardous materials adviser (HMA) must liaise with the harbour master when advising on the operational plan.

Vessels carrying dangerous goods will display a red warning flag between sunrise and sunset. Between sunset and sunrise (and during the day in restricted visibility) vessels will display an all-round, uniform and unbroken red light visible for at least two nautical miles in good night time conditions when moored or anchored.

International Maritime Dangerous Goods Code (IMDG) code

Transporting dangerous goods by sea is an international industry and is governed by an international standard; the International Maritime Dangerous Goods Code (IMDG).

The Code is used by all areas of the shipping industry that carries dangerous goods, and covers all aspects of their transportation, from the construction of the vessels to limiting quantities of substances carried.

IMDG has three volumes:

  • Volume 1 includes general provisions such as definitions, training requirements, etc.
  • Volume 2 includes the dangerous goods list and limited quantities exceptions
  • The supplement contains the emergency schedules and medical first aid guidance; it also contains two sections that are of specific interest to the hazardous materials adviser (HMA)

Marine pollutants

A number of dangerous substances are also identified as substances harmful to the marine environment; these are known as marine pollutants. Substances classified as marine pollutants are carried in packages or transport containers identified with a marine pollutant symbol. Amendment 23 of the IMDG introduced a new marine pollutant symbol of a dead fish and a tree, which replaced the previous triangle containing a dead fish and crossed lines.

Image 35 New (right) and previously used (left) marine pollutant symbols

Emergency schedule (EMS)

This is the emergency schedule for dealing with incidents involving dangerous goods that are on fire or have been spilled.


A series of generic tables with the prefix F give guidance on the specific hazards of a substance when involved in fire and the firefighting tactics that should be employed in various locations on the ship.


A series of generic tables with the prefix S give guidance on the hazards associated with various spills, personal protection and tactics for different sized packages and spills in various locations on the ship.

Medical first aid guidance (MFAG)

This section contains a flow chart to assist in the initial assessment of a casualty and refers the reader to generic numbered tables for specific conditions. In each case, casualty signs and symptoms are described and detailed treatments given. In many cases the treatments are significantly more involved than for normal first aid and are designed to preserve life whilst at sea, using the vessel’s on board medical facilities. This information can prove to be of considerable value when attempting to assess whether the casualty has been exposed to a particular substance.

However, the guidance given under EMS and MFAG is designed for use when the vessel is at sea and to assist the survival of the ship and casualties whist awaiting help. As a result, some of the tactics and procedures outlined, such as ditching the material overboard, may not be appropriate when the ship is in port.

The EMS is reproduced as a section in Chemdata. When accessing Chemdata for incidents involving ships, the user should ensure they refer to the sections on emergency schedules. This information is not only essential when formulating a plan but also will give an understanding of the actions that may have been taken by the ship’s crew prior to the arrival of the fire and rescue service.

Bulk storage of hazardous substances

The bulk storage of hazardous substances presents fire and rescue service personnel with specific problems, which are:

  • Quantities of substances stored
  • Variety of substances being stored
  • Variety of storage media
  • Proximity of other bulk storage of hazardous substances (for example, at Buncefield there were approximately 29 bulk storage tanks and three pipelines)
  • Size of the consequence area in terms of the plume, firefighting media run off, potential proximity of residential areas, etc.

The Health and Safety Executive has issued regulations and approved codes of practice for aspects of the storage of hazardous substances. The regulations and approved codes of practice require that the owner/occupier carry out a detailed risk assessment on the premises storing hazardous materials, and subsequent safety systems be implemented. It is recommended that the hazardous materials adviser refers to these documents for details on safety systems.

The safety systems are based on the assessment of the risks from:

  • Release of dangerous substances
  • Ignition sources
  • Separation of product
  • Elimination or reduction of risks from dangerous substances through:
    • Ventilation
    • Control of ignition
    • Separation of product
    • Fire resistance of  the storage media
    • Fire reaction