RoadSafe Europe

Dangerous Goods & transport training and consultancy

Useful Information

This page is intended to provide links to information regarding the carriage of Dangerous Goods by all modes of transport. We've tried to keep it simple, and hope that what you find here to be useful and informative, whatever your level of interest.

Hazard Classes

An introduction to the nine classes of Dangerous Goods, and some properties of the materials you may encounter.


All industries have their own jargon, and the transportation of Dangerous Goods is no exception. Here you will find a collection of transport and chemistry terms explained in plain English.


A review of Dangerous Goods enforcement.

Tel: 02380 702576 or, [email protected]

Hazard Classes

Dangerous goods are assigned to different classes depending on their predominant hazard. The United Nations (UN) classifies Dangerous Goods in the following classes and, where applicable, divisions. The consignor - the person or business shipping the goods - is responsible for classifying, marking and packaging the Dangerous Goods.

The nine classes are:

Class Danger Division Main Hazard
1 Explosives 1.1 Mass explosion
1.2 Projection
1.3 Flammability
1.4 Insignificant
1.5 Mass explosion
1.6 Projection
2 Gases 2.1 Flammability
2.2 Non-toxic, non- flammable gas
2.3 Toxic
3 Flammable liquids Flammability
4 Flammable solids 4.1 Flammable solids
4.2 Spontaneously combustible
4.3 Water reactive
5 Oxidizers 5.1 Oxidizers
5.2 Organic peroxides
6 Toxins 6.1 Toxic materials
6.2 Infectious substances
7 Radioactive Ionising Radiation
8 Corrosives Corrosive
9 Miscellaneous substances and articles Various

ADR Load Thresholds

There are some concessions on ADR requirements where the total goods carried in a single transport unit do not exceed the "ADR Load Limits". These limits are based on the Transport category of the goods, effectively an indication of the degree of risk they pose. these limits are shown below:

For Packaged Dangerous Goods only
Transport Category Total Dangerous Goods load*
 0  0 - All amounts count
1  20
2  333
3  1000
4  Unlimited

* Nominal capacity (litres) - liquids and compressed gas cylinders. Net mass of product (kg) - solids and liquified gases. Gross mass (kg) - articles.

The Department for Transport has devised a database of Dangerous Goods, searchable by UN number that can be freely accessed for further information by clicking HERE.

Packaging rules

Packaging has to be designed and constructed to United Nations (UN) specification standards and must prove competence by passing practical transport related tests such as being dropped, held in a stack and subjected to pressure demands. It must also meet the needs of the substance it is to contain. Packagings must be certified by a national competent authority. The Vehicle Certification Agency Dangerous (VCA) Goods Office has responsibility for the certification of dangerous goods packaging within the UK.

UN approved packaging is marked with the prefix 'UN' and followed by codes that are listed in the relevant regulations relating to the national and international carriage of dangerous goods by road, rail, air and sea.

Suppliers of Dangerous Goods are required by law to label their products with hazard symbols, warnings and safety advice. A range of internationally recognised symbols have been developed so that people handling the goods know the nature of the hazard they present.

Safety labelling requirements can vary between countries. For example, the USA has different requirements from most European countries. This means that consignments from the USA marked as Dangerous Goods frequently need to be re-labelled once they are transported into the European Union.

Transport Documents

The ADR regulations require specific information to be included in a "Transport Document", and for this information to be shown in a specific format, as shown below:

A) The UN Number, preceded by the letters “UN”.

B) The Proper Shipping Name supplemented, when applicable, with the technical name. This is normally required when the proper Shipping name is an ‘N.O.S’ entry. Trade names alone must not be used.

C) The number shown in the bottom of the primary hazard class label followed by any subsidiary hazard label numbers shown in brackets.

D) The Packing Group, where assigned, for the substance which may be preceded with the letters “PG” (e.g. PG II).

E) The number and kind of packages (e.g. 5 x 200 ltr steel drums). There is no need to specify details of inner receptacles or inner packagings, although when shipping as Limited Quantities it is advisable to do so.

F) The total quantity of each item of dangerous goods bearing a different UN number, proper shipping name, or, when applicable, packing group (as a volume or as a gross mass, or as a net mass as appropriate).

G) The name and address of the consignor.

H) The name and address of the consignee(s), or the words "delivery sale" if there are multiple consignees who cannot be specified.

I) A declaration as required by the terms of any special agreement.

K) Where assigned, the tunnel restriction code shown in capitals enclosed within brackets.

The order of the data formulating the transport document description should be A), B), C), D) and K), with no information interspersed, except as provided for in ADR. For example:

  • UN 1230, METHANOL, 3,(6.1), PGII, (C/D)

NOTE – for combined sea and road/rail transport, consignments that fully meet the requirements of the IMDG code shall be accepted for carriage under ADR/RID, and a statement shall be included the transport document as follows: “Carriage in accordance with”. IMDG consignments are generally accompanied with a Dangerous Goods Note. A guide to completing these forms can be found by clicking HERE (opens in a new window).


On this page you will find definitions of some common chemistry, transport and technical terms. This is by no means an exhaustive list, so if you can't find the term you're after please feel free to contact us by clicking HERE, and we'll do our best to assist you.


  • Absorption
    • A process in which one substance, usually a liquid or gas, is taken into the body of another.
  • ACHS
    • Advisory Committee on Hazardous Substances
  • Acid
    • A substance with a pH reading of 0-7
  • ACOP
    • Approved Code Of Practice
  • ADR
    • "l'Accord relatif au transport international des marchandises Dangereuses par Route." The agreement concerning the carriage of Dangerous Goods by road
  • Adsorption
    • A process where materials stick to the surface of a solid body
  • Aerobic
    • Operating in the presence of Oxygen
  • Agrochemicals
    • Substances used for agricultural purposes, includes fertilizers, herbicides, insecticides, pesticides and plant growth regulators.
  • Alkali
    • A substance with a pH reading 0f 7-14
  • Anaerobic
    • Operating in the absence of Oxygen


  • BA
    • Breathing Apparatus
  • Becquerel (Bq)
    • A unit of radioactivity
  • Biodegradable
    • Having the ability to decompose through the action of bacteria
  • BOD
    • Biological/Biochemical Oxygen Demand


  • CAA
    • Civil Aviation Authority
  • Carcinogen
    • A substance which causes cancer
    • Conseil Europée d l’Industrie Chemique
  • CFCs
    • Chlorofluorocarbons
  • CHIP
    • Chemicals (Hazard Information and Packaging) Regulations
  • CIA
    • Chemical Industries Association
  • Clinical waste
    • Any waste which consists wholly or partly of human or animal tissue, blood or other body fluids, excretions, pharmaceuticals, dressings, sharps etc
  • COD
    • Chemical Oxygen Demand
  • Consignee
    • The receiver of the Dangerous Goods
  • Consignment Note
    • The Transport document used for the carriage of Hazardous Wastes in the UK
  • Consignor
    • The sender of the Dangerous Goods
  • Contaminated Land
    • Land which because of it’s current or previous use has substances under, on or in it which may be hazardous to life or the environment
  • Controlled Waste
    • Wastes from households, industry and commerce, excluding mines, quarries, sewage and some radioactive wastes.
    • Control Of Substances Hazardous to Health
  • COTC
    • Certificate Of Technical Competence
  • CPC
    • Certificate of Professional Competence (for transport managers and drivers)
  • Cryogenic gas
    • A gas liquefied by super-cooling to below -100 degC
  • CWC
    • Chemical Weapons Convention


  • DfT
    • Department for Transport
  • DGN
    • Dangerous Goods Note
  • DGSA
    • Dangerous Goods Safety Adviser
  • Dioxins
    • Collective name for a group of compounds called dibenzo-p-dioxins.


  • EA
    • Environment Agency
  • Ecotoxics
    • Substances or preparations, which present an immediate risk to the environment.
  • Effluent
    • Any waste liquid from an industrial process
    • European Inventory of Existing Commercial Chemical Substances
  • Element
    • A substance that cannot be reduced chemically into a simpler substance.
  • ELVs
    • End-of-Life Vehicles
  • Emergency Action Code
    • Code shown on UK tankers and bulk vehicles giving safety information for the Emergency Services
  • EmS
    • Emergency Schedules (for fire, spillages and first aid, found in the IMDG code)
  • EPA
    • Environmental Protection Agency (USA)
  • EWC
    • European Waste Catalogue
  • Exotherm
    • A chemical reaction which causes heat to be given out


  • Fauna
    • The animals of a region
  • Flash Point
    • The lowest temperature of a liquid at which its vapour may form a flammable mixture with air, abbreviated by Fpt.
  • Flora
    • The plants and trees of a region
  • Fly-tipping
    • The illegal depositing of waste


  • Half-Life
    • The time taken for half the atoms of a radioactive isotope to disintegrate.
  • Hazard class
    • Nine divisions of dangerous goods determined by their primary risk
  • Hazardous Waste
    • Wastes identified in the Hazardous Waste and List of Wastes Regulations 2005
  • Heavy Metals
    • Generally refers to Arsenic, Antimony, Cadmium, Chromium, copper, Lead, Mercury, Nickel, Selenium and Zinc.
  • HSE
    • Health and Safety Executive
  • Hydrocarbons
    • Organic compounds consisting of Carbon and Hydrogen


  • IATA
    • International Air Transport Association
  • IBC
    • Intermediate Bulk Container
  • ICAO
    • International Civil Aviation Organisation
  • IMDG Code
    • International Maritime Dangerous Goods Code
  • IMO
    • International Maritime Organisation
  • Inert
    • Inactive or unreactive
  • Inorganic
    • A material based on any chemical element other than carbon
  • ISPS code
    • International Ship and Port facilities Security code
  • IWM
    • Institute of Wastes Management


  • Kemler Code
    • A similar system to the UK’s Emergency Action Code, used throughout Europe to identify the primary hazard of liquids or solids in tankers


  • Label
    • A diamond shape indicating a UN hazard class
  • Landfill tax
    • Announced in the Budget of Nov. 1994 as a tax intended to encourage recycling and discourage landfilling of waste.
  • LC50
    • Lethal concentration of a gas or vapour that will kill 50% of all organisms exposed to it.
  • LD50
    • Lethal dose of a substance that will kill 50% of all organisms exposed to that dose.
  • Leachate
    • Contaminated waters running off of, or percolating through a landfill site
  • LEL
    • Lower Explosive Limit.
  • Limited Quantities
    • A method of carrying Dangerous Goods that are exempted from most legislation by virtue of the small volumes in each package.
  • Load Limit
    • The quantity of dangerous goods that must be loaded onto a vehicle at which the ADR regulations will be fully applied.
  • LPG
    • Propane or Butane (or a mixture of the two) which has been liquefied for transport


  • Marks
    • Information attached to a package or vehicle other that a label or placard
    • International Convention for the Prevention of Pollution from Ships (MARine POLlutant)
  • MEL
    • Maximum Exposure Limit
  • MFAG
    • Medical First Aid Guide (in IMDG)
  • Mutagen
    • An agent capable of modifying the DNA in the genes, causing mutations.


  • NOS
    • Not Otherwise Specified


  • OEL
    • Occupational Exposure Limit
  • Organic
    • Pertaining to carbon
  • Oxidizer
    • A material that has the ability to provide oxygen to a chemical reaction


  • Packing Group
    • A method of indicating varying risks posed by different substances within a single UN class. PGI- most dangerous, PGII – medium danger, PGIII – Least danger
  • PCB
    • Polychlorinated Biphenyls (see Class 9 substances)
  • Petrochemicals
    • Chemicals derived from petroleum, hydrocarbon liquids or natural gas.
  • Phytotoxic
    • Poisonous to plants
  • Placard
    • Essentially a large chemical hazard diamond attached to a vehicle or tank
  • PSN
    • Proper Shipping Name
  • Putrescible Wastes
    • Wastes, which consist of plant or animal residues which undergo bacteriological degradation when landfilled.


  • Registered Carrier
    • A person registered to transport controlled waste
  • RID
    • The European agreement for the carriage of Dangerous Goods by rail - Reglement concernant le transport International ferroviare des merchandises Dangereuses
  • Ro/Ro
    • Roll On-Roll Off, a design of ferry
  • Rollonoff
    • A Roll On-Roll Off waste container, usually of 11- 28M3 capacity


  • SADT
    • Spontaneous Auto-Decomposition Temperature
  • SIN
    • Substance Identification Number – As UN number
  • SLF
    • Secondary Liquid Fuel: Waste flammable liquids used to fire cement kilns
    • Safety Of Life At Sea
  • Solvent
    • Liquid that has the ability to dissolve other substances


  • Teratogenic
    • Capable of causing abnormal development of the embryo and congenital  malformations (From terato = monster (Greek))
  • TLV
    • Threshold Limit Value
  • TOC
    • Total Organic Carbon
    • Tanker Owners Voluntary Agreement Concerning Liability for Oil Pollution
  • Transfer Note
    • A document which identifies waste that is transported
  • Transport Category
    • Materials are assigned to a category of 0-4 in order to determine the Load Limits at which ADR regulation is applied


  • UEL
    • Upper Explosive Limit.
  • UN Number
    • An internationally recognised four-digit identification number for an item of Dangerous Goods


  • VOC
    • Volatile Organic Carbon
  • VTC
    • Vocational Training Certificate (a.k.a. ADR licence)


    • Waste Management Industry Training Advisory Board

Tunnel Restrictions

On 1st January 2010, new restrictions on the types and quantities of Dangerous Goods that are allowed to enter the UK's larger road tunnels came into force.

Each regulated tunnel is assigned to a particular category, A to E, A being the least restrictive (shown by a "" in the ADR manuals), and E being the most. These are based on a risk assessment conducted by the DfT of the tunnel characteristics, availability and suitability of available alternative routes and other traffic management considerations.

The categorization was based  on the assumption that in all tunnels there are three major dangerers that may cause serious damage to the tunnel, or loss of life - explosions, release of toxic gas or volatile toxic liquid, and fires.

Tunnel categories (ADR 2021,


  • No restrictions for the transport of Dangerous Goods;


  • Restriction for Dangerous Goods which may lead to a
    • very large explosion


  • Restriction for Dangerous Goods which may lead to a
    • very large explosion,
    • large explosion or a
    • large toxic release;
    • Dangerous Goods restricted in tunnel category B,


  • Restriction for Dangerous Goods which may lead to a
    • very large explosion,
    • large explosion,
    • large toxic release or
    • large fire;
    • Dangerous Goods restricted in tunnel category C,


  • Restriction for all Dangerous Goods other than UN Nos. 2919, 3291, 3331, 3359 and 3373.

Tunnel restrictions (ADR 2011, 8.6.4)

Tunnel restriction code
of total load
 ─ Passage allowed through all tunnels
(an "A" Tunnel)
B Passage forbidden through tunnels of category B, C, D & E
B1000C Carriage where the total net explosive mass per vehicle:

  • exceeds 1000kg, passage forbidden through tunnels of category B, C, D & E
  • under 1000kg, passage forbidden through tunnels of category C, D & E
B/D Tank carriage: Passage forbidden through tunnels of category B, C, D & E;
Other carriage: Passage forbidden through tunnels of category D & E
B/E Tank carriage: Passage forbidden through tunnels of category B, C, D & E;
Other carriage: Passage forbidden through tunnels of category D & E
C Passage forbidden through tunnels of category C, D & E
C5000D Carriage where the total net explosive mass per vehicle:

  • exceeds 5000 kg: passage forbidden through tunnels of category C, D & E;
  • under 5000kg: passage forbidden through tunnels of category D & E
C/D Tank carriage: Passage forbidden through tunnels of category C, D & E;
Other carriage: Passage forbidden through tunnels of category D & E
C/E Tank carriage: Passage forbidden through tunnels of category C, D & E;
Other carriage: Passage forbidden through tunnels of category E
D Passage forbidden through tunnels of category D & E
D/E Bulk or tank carriage: Passage forbidden through tunnels of category D & E
Other carriage: Passage forbidden through tunnels of category E
E Passage forbidden through tunnels of category E


In the UK, the carriage of Dangerous Goods by inland waterway is subject to the Dangerous Substances in Harbour Areas Regulations 1987, or British Waterways by-laws. The amount of such goods moved by this mode within the UK is small. What movement there is tends to be petroleum products, and is centred on the Thames, Trent and Humber waterways.

ADN (L'Accord europeen relatif au transport international des merchandises Dangereuses par voies de Navigation interieures) is the European Agreement concerning the International Carriage of Dangerous Goods by Inland Waterways. It was adopted in May 2000 by a Diplomatic Conference held in Geneva, and entered in to force on 29th February 2008.

The ADN is to water transport what ADR is to road.

It is important to note the distinction between open sea transport (which is IMO's responsibility, the IMDG Code) and inland waterways (such as the rivers Rhine, Rhone, Waal, Danube, etc).

The two-volume ADN manuals explain all the exceptions and particulairities concerning the shipping procedures and preparations, documents, etc. Under the agreement, all European countries agree to adhere to the same methods of training, control and activities of security agents in this field. But, as the UK has no international inland waterways, it is not a signatory to the agreement, and ADN is therefore not used here.

ADN only applies in the UK in relation to the training and examination system for safety advisers and the connected issuing and renewal of vocational training certificates. It does not apply to the carriage of dangerous goods by inland waterways within the UK, as there is no physical connection between them and the European inland waterways.

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