Last reviewed 11 May 2022

In this feature article, Caroline Raine provides an introduction to the transport regulations, explaining the different modes and some of the relaxations available.

Modes of Transport

There are five modes of transport:

  • Road — ADR

  • Rail — RID

  • Air — IATA

  • Sea — IMDG

  • Inland waterways — ADN.

The Department for Transport (DfT) is ultimately responsible for all modes.


The Agreement Concerning the International Carriage of Dangerous Goods by Road (ADR) was published in 1957 and came into force in 1968. Modelled on the UN Orange Book model regulations and published in two volumes, the ADR Agreement is also revised and republished every two years, and comes into force on 1 January of each odd numbered year. The edition is referred to by the year in which it comes into force.


The Regulations concerning the International Carriage of Dangerous Goods by Rail (RID) have been long in development. Like the ADR Agreement, they are now modelled on the UN Orange Book Model Regulations on the transport of dangerous goods.


Aviation safety is highly regulated and the International Civil Aviation Organisation (ICAO) prepares international provisions for moving dangerous goods by air. ICAO was established by the International Convention on Civil Aviation (Chicago Convention) 1944. Based on the UN Orange Book Model Regulations, it publishes the Technical Instructions for the Safe Transport of Dangerous Goods by Air. The ICAO Technical Instructions (TIs) are revised and published every two years and come into force on 1 January of every odd numbered year. The edition is known by the years in which it will remain applicable (eg 2017–2018).

In addition, each year the International Air Transport Association (IATA) publishes the IATA Dangerous Goods Regulations (DGR). They constitute a manual of rules to be followed by all IATA member airlines and include all the requirements of the ICAO TIs, plus additional terms and conditions applied by IATA. While not having the same legal force as the ICAO TIs, to have dangerous goods accepted for carriage by air, consignors must meet the provisions of the IATA Dangerous Goods Regulations. These are referenced by the edition number, eg 63rd for the edition applicable in 2022.

Sea and Inland Waterways

The International Maritime Dangerous Goods Code (IMDG Code) sets out the conditions applicable for the safe transport of dangerous goods and marine pollutants by sea in packaged form (including tanks/tank containers) and solids in bulk. Vehicles carrying dangerous goods travelling on ferries (whether on international journeys or within UK waters, eg to and from islands) must meet the requirements of the IMDG Code.

Based on the UN Orange Book Model Regulations, the IMDG Code is published by the International Maritime Organisation (IMO), is revised every two years, and comes into optional operation on 1 January in odd-numbered years with mandatory application from 1 January of the following even-numbed year. It is known by the year of publication (ie the even-numbered year prior to its first use), rather than by the year when it can be first applied. In Britain, the Maritime and Coastguard Agency (MCA) oversees the implementation and enforcement of the IMDG Code.

Similarly based on the Orange Book Model Regulations, and developed in conjunction with ADR and RID, the European Agreement Concerning the International Carriage of Dangerous Goods by Inland Waterways (ADN) is revised and published every two years, with new additions coming into force on 1 January of odd-numbered years.

The UN Orange Book

The UN Recommendations and Model Regulations are often referred to as the “Orange Book” due to the colour of the cover. The book is updated biennially, in December of even numbered years, although it is not published until the following year. It is known by its revision number, eg 21st, and not by any year.

Although not directly applicable to shippers, the Orange Book is of considerable interest as changes to the Model Regulations are likely to be adopted by the international and national authorities in due course. The Model Regulations have, without doubt, reached the pre-eminent position in dangerous goods “legislation” and their use as a basis for worldwide modal regulations contributes both to safety and to the facilitation of trade.

The following are the basic concepts of the UN Model Regulations:

  • classification rules

  • nine danger Classes (some split into Divisions)

  • the allocation of proper shipping names and UN numbers which enable dangerous goods to be identified anywhere in the world

  • packaging provisions

  • intermediate bulk container provisions

  • multi-modal tank provisions

  • labelling, marking and placarding requirements

  • rules for documentation.

The other regulations use the detail in the orange book.


Exemptions for the transport of dangerous goods by road can be found in Chapter 1.1.3 of ADR and the current UK Carriage of Dangerous Goods Approved Derogations document.

A few examples of applicable exemptions by road are:

  • a maximum of 60 litres can be carried in fuel containers such as Jerri cans in a vehicle

  • moving goods between private premises across a public road

  • small quantities of substances and articles can be carried with relaxation to the regulations

  • <5 kg/litres of environmentally hazardous substances is exempt from all modes

  • machinery which contains dangerous goods, ie fuel, provided that leaks are prevented

  • dangerous goods packaged and carried in limited quantities provided conditions are met.

Please note that this list is not exhaustive.

ADR — exemptions related to the nature of the transport operation

The provisions laid down in ADR do not apply to the carriage undertaken by enterprises which is ancillary to their main activity, such as deliveries to or returns from building or civil engineering sites, or in relation to surveying, repairs and maintenance, in quantities of not more than 450 litres per packaging, including intermediate bulk containers (IBCs) and large packagings, and within the maximum quantities specified in Measures shall be taken to prevent any leakage of contents in normal conditions of carriage. These exemptions do not apply to Class 7.

Carriage undertaken by such enterprises for their supply or external or internal distribution does not fall within the scope of this exemption.

Limited Quantities (LQ)

Under the Carriage of Dangerous Goods Regulations, LQ goods can be carried without having to meet the usual requirements. Dangerous goods are assigned an LQ value, the maximum volume per inner package that can be used. The maximum mass of combination packaging and substance or article cannot be more than 30kg which includes the inner packaging and strong outer packaging. Shrink- and stretch-wrapped trays cannot be more than 20kg.

UN-approved packaging does not have to be used for LQ goods, although general packaging rules do apply. Each LQ category has specific packaging limits and particular labelling requirements, depending on the category they are in. LQ goods may be packed together with other articles or substances, as long as they will not react dangerously if leakage occurs.

Transport Categories — Small Load Thresholds

Transport categories are used to determine the amount of packaged dangerous goods that can be carried under small quantity load relaxations to the regulations before the full ADR requirements apply. Chapter of ADR and Table A column 15 for the Transport Category for each substance or article.

Small Quantity Loads — Exemptions: for dangerous goods at or below the small load quantity thresholds, the following general exemptions apply and some requirements still apply.

  • No ADR Driver Training Certificate or license required, but basic training in carriage of dangerous goods is required.

  • No orange warning plates required.

  • No need to carry driver Instructions in writing.

  • The vehicle must carry a minimum of a 2kg fire extinguisher in cab of vehicle.

  • Smoking is not permitted.

  • Applicable stowage, parking and supervision rules apply.

  • Packaging, marking and labelling requirements apply.


The transport of dangerous goods is heavily regulated to ensure the safety of all involved in the process. There are agreements in place to reduce the onerous requirements where the risk is lower, so rather than assuming the load must be fully regulated, always check to see if any of the exemptions, derogations, limited quantities, small load thresholds or special provisions can make the load easier and cheaper to transport.

If you are unsure of the Regulations always seek advice from your Dangerous Goods Safety Advisor (DGSA).