EC number

The EC number comes from European inventories. The oldest, EINECS, lists substances that were on the market in the European Community between 1 January 1971 and 18 September 1981. ELINCS lists new substances notified after 18 September 1981, and the NLP (No-Longer Polymers) list covers substances that stopped counting as polymers when the polymer definition changed in 1992. All of these numbers fall under the umbrella name EC number.

It serves a similar purpose to a CAS number but is maintained by the EU rather than by a private registry. A single Substance normally has one of each, though the systems do not always match one for one, and some substances have an EC number but no CAS number, or the reverse.

You will see EC numbers in Section 3 of a European SDS alongside CAS numbers, and on the substance list under the CLP Regulation. They also appear in REACH registration dossiers and in the list of substances of very high concern.

North American users might see EC numbers less often, but they matter when you import or export, buy from European suppliers, or compare documents produced for the EU market.

Like CAS numbers, EC numbers identify substances, not mixtures.