EC Number

What is the EC number and what is it used for in the identification of chemical substances?

The EC number is a numerical identifier used in the European Union to unequivocally recognise a chemical substance within different regulatory processes.

This identifier, assigned by European authorities, is used in official databases and technical documentation to facilitate the management, control and communication of information related to the use, classification and safety of chemical substances throughout their life cycle.

What does EC mean and how is the number structured?

The initials CE stand for European Community. It is a purely identificative code, with no chemical meaning in itself. It is usually presented in the following format:

XXX-XXX-X

In current European systems, identifiers associated with chemical substances are not necessarily limited to exclusively numerical formats and may include alphanumeric formats depending on the type of identification used.

Historically, when EC numbers were expressed only using numerical characters, the irst digit of the identifier indicated the origin of the substance in European reference inventories or lists. This criterion helps to understand where the information associated with a substance comes from, although the EC number remains, in all cases, a purely technical identifier.

In general terms, the first number could indicate:

• 2XX-XXX-X y 3XX-XXX-X: substances included in the EINECS inventory (European Inventory of Existing Commercial Chemical Substances).
• 4XX-XXX-X: substances included in ELINCS (European List of Notified Chemical Substances).
• 5XX-XXX-X: substances included in the NLP list (List of substances No Longer considered Polymers).
• 6XX-XXX-X, 7XX-XXX-X, 8XX-XXX-X AND 9XX-XXX-X: identifiers originating from lists managed by the European Chemicals Agency (ECHA), assigned according to different technical criteria.

Identifiers that already existed with these formats retain their original meaning, as updates introduced in European systems are not applied retroactively and can be consulted in official tools such as ECHA CHEM.

What is the EC number used for?

The EC number is mainly used to:

• Identify chemical substances in European databases.
• Facilitate the regulatory management of substances.
• Ensure consistent identification in technical and regulatory documentation.
• Support the classification and communication of hazards.

Its use helps to avoid confusion arising from the existence of multiple chemical names or synonyms for the same substance.

Where is the EC number used?

The EC number commonly appears in different areas related to the management of chemical substances, such as:

• Safety Data Sheets (SDS).
• Documentation associated with Regulation (EC) Nº1907/2006 (REACH).
• Labelling and communication of chemical substances.
• European databases managed by ECHA.
• Internal substance identification systems in industrial environments.

Its use is particularly relevant in the European context, where it acts as a common reference for companies, users and competent authorities.

Are the EC number and the CAS number the same?

Although both are systems for identifying chemical substances, the EC number and the CAS number are not equivalent.

• The CAS number is an internationally widely used identifier.
• The EC number is an identifier specific to the European regulatory framework.

In practice, both numbers often appear together in the technical documentation of a substance, as they fulfil complementary functions and allow cross-identification in different databases.

What happens with new substances?

Not all substances automatically have an EC number, especially those that were not included in the original European inventories.

In these cases, the identification of the substance is managed within the corresponding regulatory procedures, and the EC number is assigned when appropriate, depending on its incorporation into European reference systems.

Why is the EC number important in SDS and in the classification of chemical substances?

The EC number plays a relevant role in the preparation and management of Safety Data Sheets, as it contributes to the correct identification of the substance, facilitates consistency between different regulatory documents and enables clear communication between suppliers, users and authorities.

In addition, its use is linked to the processes of classification and communication of hazards, as it allows a specific substance to be associated with its regulatory, toxicological and environmental information within European systems, thus promoting more effective chemical safety management.