European Agreement concerning the International Carriage of Dangerous Goods by Road

ADR (formally, the European Agreement concerning the International Carriage of Dangerous Goods by Road (ADR)) is a 1957 United Nations treaty that governs transnational transport of hazardous materials. "ADR" is derived from the French name for the treaty: Accord européen relatif au transport international des marchandises Dangereuses par Route).

Concluded in Geneva on 30 September 1957 under the aegis of the United Nations Economic Commission for Europe, it entered into force on 29 January 1968. The agreement was modified (article 14, paragraph 3) in New York City on 21 August 1975, though these changes only took effect on 19 April 1985. A new amended ADR 2011 entered into force on 1 January 2011. Annexes A and B have been regularly amended and updated since the entry into force of ADR. Consequently, to the amendments for entry into force on 1 January 2015, a revised consolidated version has been published as document ECE/TRANS/242, Vol. I and II.

As of 2016, 49 states are party to ADR.

The agreement itself is brief and simple, and its most important article is article 2. This article states that with the exception of certain exceptionally dangerous materials, hazardous materials may in general be transported internationally in wheeled vehicles, provided that two sets of conditions be met:

The appendices consist of nine chapters, with the following contents

The classes of dangerous goods according to ADR are the following:

Each entry in the different classes has been assigned a 4 digit UN number. It is not usually possible to deduce the hazard class(es) of a substance from its UN number: they have to be looked up in a table. An exception to this are Class 1 substances whose UN number will always begin with a 0. See List of UN numbers

ADR pictograms for chemical hazards are based on GHS Transport pictograms and Non-GHS transport pictograms

1-Explosives

2.1-Flammable gases

2.2-Non-toxic and non-flammable gases

2.3 Poison gases

3-Flammable liquids

4.1-Flammable solids

4.2-Spontaneously combustibles

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