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Vol. 31 No. 2
March-April 2009

Customs, Chemistry, and IUPAC: An Old Story

by Hervé Schepers

A 1788 sign describing customs, tolls, and duties of the Corporation of Kinsale, a town in County Cork, Ireland.

For many people, mention of a customs authority or agency brings to mind those annoying officials at the border who inspect your luggage and confiscate your travel souvenirs. Obviously, this is only a partial view of what customs does. Customs is responsible for collecting and safeguarding customs duties and for controlling the flow of goods, including animals, personal effects, and hazardous items, in and out of a country. Depending on local legislation and regulations, the import or export of some goods may be restricted or forbidden, and the customs agency enforces these rules.

Customs authorities have existed in some form since the earliest civilizations. Archaeologists and historians have discovered many artifacts and documents related to ancient customs operations, including numerous, sometimes very detailed, catalogs of goods subject to tariffs. In the past, tariffs formed a much larger part of government revenue than they do today. Modern customs authorities are more involved in the protection of the economy, health, environment, and security. In particular, customs authorities are responsible for controlling the flow of illegal drugs, chemical weapons, ozone-depleting substances, and many other dangerous chemicals. Customs can be seen as an interface with the rest of the world: Everything coming in or going out passes through customs offices.

Customs authorities and chemistry have been linked for hundreds if not thousands of years. In all likelihood, officials in antiquity controlled the quality of wine or olive oil. In Europe, modern customs chemistry labs trace their origins back at least 150 years ago. The Austrian Customs laboratory was founded in 1848. Jacobus H. van’t Hoff, winner of the Nobel Prize in Chemistry in 1901, led the Dutch Customs laboratory. Today, European Customs includes an impressive network of 81 well-equipped and mostly accredited laboratories.

Customs and IUPAC are deeply linked in three ways: legislation, translation, and identification.

The European Commission’s Taxation and Customs Union produces legislation and procedures for customs, including the calculation of customs duties. An essential part of its function is the publication of a “customs nomenclature” or Combined Nomenclature (CN)1
for customs, which lists all traded goods. This nomenclature is based on the Harmonized Commodity Description and Coding System of the World Customs Organization and serves as a basis for other regulations, such as autonomous suspension of customs duties and the pharmaceutical–General Agreement on Tariffs and Trade agreement. The CN code is one of the most important elements in the customs declaration and in customs control.

One extract of the Combined Nomenclature
CN code
Conventional rate of duty (%)
2933 99 20 Indole, 3-methylindole (skatole), 6-allyl-6,7-dihydro-5H-dibenz[c,e]azepine (azapetine), phenindamine (INN) and their salts; imipramine hydrochloride (INNM)

Because customs operations require a precise and clear international language for chemicals, the European Customs Union and the World Customs Organization decided long ago to use the IUPAC nomenclatures in their Combined Nomenclature and, subsequently, in all legislation. Especially in the customs field, precision is important, because customs duties, preferential duties, and prohibitions are often applied according to a specific name. When the name in the legislation and the name on the customs declaration or on the invoice do not correspond, it can have important consequences for businesses in terms of money or time.

For customs officials, different names mean different products; they cannot be blamed, they are not chemists. For example, o-cresol, ortho-cresol, and 1,2-cresol might be considered three different products, or “acetic acid, ethyl ester” as a group of two products.

But, IUPAC names are not a perfect solution either. Creating a good name is not necessarily easy, even for a chemist with the “recommended,” “accepted,” or “discarded” options to choose among. And customs officials do not like names like methyl (1R,4Z,8S,13E)-13-[2-[[2-[[[p-(3-carbamoylpropoxy)-α-methylbenzylidene]hydrazino]carbonyl]-1,1-dimethylethyl]dithio]ethylidene]-8-[[4,6-dideoxy-4-[[[2,6-dideoxy-4-S-[4-[(6-deoxy-3-O-methyl-α-L-mannopyranosyl)oxy]-3-iodo-5,6-dimethooxy-o-toluoy]-4-thio-β-D-ribo-hexopyranosyl]
-3-O-methyl-α-L-threo-pentopyranosyl]-b-D-glucopyranosyl]oxy]-1-hydroxy-11-oxobicyclo[7.3.1]trideca--4,9-diene-2,6-diyne-10-carbamate (ozogamicin (INN)).

If the creation of a chemical name is difficult, the translation can be a real nightmare. To start, all European Union legislation must be translated into 22 languages (the customs tariff is not yet translated into Irish). Regularly, new member states join the EU, adding new languages to the translation list.

Example of the modifications needed in the translation of a chemical name into some of the European languages.

Clearly, customs is a legal domain in which the difference of one letter or number is important. The translation of chemical names into 22 languages involves numerous modifications to concatenation, inversion, letters, word endings, alphabetical order of substituents, and first capital letters. The sources for mistakes are numerous.

An example of a simple chemical name in all the current EU languages follows:

Калциев хлорид
Chlorid vápenatý
Χλωριούχο ασβεστίου
Calcium chloride
Cloruro de calcio
Chlorure de calcium
Cloruro di calcio
Kalcio chloridas
Kalcija hlorīds
Klorur tal-kalċju
Chlorek wapnia
Cloreto de cálcio
Clorură de calciu
Chlorid vápenatý
Kalcijev klorid

The Customs Union typically uses specialized translators, normally chemists, for this work, but they may not be specialized in organic chemistry, certainly the biggest and the most difficult part of the IUPAC nomenclatures. Moreover, the time pressure involved increases the difficulty of the work. Even for a trained translator, an “o-cresol” can easily be mistyped “p-cresol.” But for a customs official, this is clearly another product.

The opposite situation can also occur because of a too-clever translator. He/she may be an organic chemist who understands clearly what he/she is translating. However, problems can arise if this translator recognizes a mistake in the customs regulations and writes down the correct name. This issue is compounded if his/her 21 colleagues follow the original text.

The very clever translator:


Malonylurea (barbituric acid) and its salts
Barbitūro rūgštis (2,4,6(1H, 3H, 5H)-pirimidintrionas) ir jos druskos
instead of Malonilkarbamidas (barbitūro rūgštis) ir jos druskos

The amount of trade passing through European borders is enormous, yet everything has to be declared and often controlled. About 200 million customs declarations are made per year in the EU. Chemicals and pharmaceuticals represent an important part of this trade. Needless to say, businesses don’t like to waste time with burdensome controls, so customs officials face increasing pressure to do their jobs quickly. The decision time for customs officials can be as small as a few seconds or a few minutes. Moreover, the description of a chemical is often not an IUPAC name or not necessarily a good IUPAC name, and it may be in German or Danish or possibly in another alphabet, such as Greek or Bulgarian. Customs officials are helped by risk analysis data, but, faced with such a large number of synonyms and languages, they might accidentally release for free circulation or export a dangerous chemical.

Some of the 80 or more names of DDT (ISO):
Clofenotane (INN)
α,α-Bis(p-chlorophenyl)-β, β,β-trichlorethane
Pentachlorin, pp’-DDT, para,para’-DDT
Zeidane, pp’-zeidane
Agritan, Gesapon, Gesarex, Gerasol, Guesapon, Neocid

The European Customs Inventory of Chemical Substances
To remedy these problems and facilitate customs operations and world trade, the European Commission’s Taxation and Customs Union launched the European Customs Inventory of Chemical Substances (ECICS)2
in the early 1970s. The ECICS is an inventory of chemicals that includes their customs classification and their IUPAC names whenever possible.

The database currently contains 30 000 traded or controlled chemicals, in particular INN pharmaceuticals, ISO pesticides, drugs and precursors, chemical weapons and precursors, and chemicals harmful to the ozone layer, human health, and the environment. The goals of the database are twofold: to provide the correct customs classification, in order to find easily the correct rate of duty; and to identify dangerous chemicals, even if they are hidden behind another name or another language. It is interesting to note that ECICS is used worldwide: the first six digits of the customs classification are common to the whole world, and the database is freely accessible on the Internet.
Given the difficulty of translating chemical names, especially with an increasing number of languages, EU customs officials created an “automatic” translator of IUPAC names into all EU languages. The current translation module, built in the 1980s, has been useful over the years, but utilizes old technology, is quite manual, and only works in 11 languages.

New Developments
New translation software named ECICS-2 is in development, which will include more products, more synonyms, more data, and more features. For example, it creates links between customs and transport (United Nations Dangerous Good numbers), health, and environment. It also includes the very interesting InChI and InChI Key identifiers.3

Two projects involve the IUPAC nomenclatures: the complete revision of ECICS names according to the latest nomenclatures, and construction of a new translation module, based on the latest nomenclatures and including all EU languages. The chemical software company ACD UK Ltd. is assisting with these projects. The database will include all nomenclatures: organic, natural products, biochemicals, inorganic, and polymers.

Of special interest to the IUPAC community is whether ECICS will list on its website all examples listed in the nomenclatures and indicate whether they are “recommended,” “accepted,” or “obsolete” names. In this framework, the “preferred IUPAC names” (PIN) used in organic and inorganic chemistry would be especially helpful. Use of these PINs would make the work of customs officials easier, because regular IUPAC names can be difficult, especially for nonchemists. Likewise, work performed for this new translation module could help in the translation of the “IUPAC color books.”

Another project will be to update the Harmonized Commodity Description and Coding System Explanatory Notes with up-to-date IUPAC names and improved chemical structures based upon the new recommendations on graphical representation standards for chemical structure diagrams. Even if this project is performed under the authority of the World Customs Organization, the European Customs will strongly support the update.

As this summary of customs laboratories shows, IUPAC nomenclature reaches more broadly than many might expect.

1. Commission Regulation (EC) No 1031/2008 of 19 September 2008 amending Annex I to Council Regulation (EEC) No 2658/87 on the tariff and statistical nomenclature and on the Common Customs Tariff,


3. The IUPAC International Chemical Identifier, <>

Hervé Schepers <[email protected]> European Commission, DG Taxation and Customs Union.

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