EC numbers are used to identify specific chemical substances, and are valid for identifying chemical substances in CLP and on the Safety Data Sheet.
EC numbers are issued by the European Community (EC, now the European Union, EU), and have been in use since the early 1980s, when the EINECS list was collated.
EC numbers comprise:
- EINECS numbers, form 2XX-XXX-X and 3XX-XXX-X (the EINECS list of substances existing on the EEC market in 1981, excluding polymers)
- ELINCS numbers, form 4XX-XXX-X (new substances added to the EEC/EU market since 1981 which have gone through the NONS process)
- NLP numbers, form 5XX-XXX-X (substances not initially given an EINECS number in 1981, but which have been declared not to be polymers since that time, so this is an equivalent to an EINECS number)
However, the same format of number is also used for administrative numbers called “list numbers”, which are also issued by the EC/EU.
List numbers include:
- Substances pre-registered with a CAS number and no EC number, 6XX-XXX-X and 8XX-XXX-X
- Substances assigned a number after an Inquiry at ECHA 7XX-XXX-X (already placed on EU market before 2008 but without an EC number)
- Substances pre-registered without a CAS number or EC number, 9XX-XXX-X
As you can see, both EC numbers and list numbers take the form of XXX-XXX-X, however only EC numbers have legal status, and list numbers are used for administrative purposes by the EU. It is very important to distinguish between the two types.
EC numbers are valid for use as substance identification numbers on CLP labels and associated Safety Data Sheets, but list numbers are not valid.
A short-hand way to remember the difference is that 2 to 5 prefix numbers are valid EC numbers, but 6 to 9 prefix numbers are list numbers.
Like CAS numbers, there can occasionally be more than one EC number (or list number) for a unique chemical substance. Many chemicals on the European market have a single CAS number, and a single EC number; or a single CAS number and a single list number.