Substance identification

To clearly identify the substances that you are registering, you need to include the following information in your registration dossier:

  • Substance name and related identifiers. These include the IUPAC name, EC number, and the CAS name and number. 
  • Molecular and structural formula.
  • Information on the composition and purity of the substance.
  • Spectral data and other analytical information to verify the identity and composition of the substance.

As a registrant, you are responsible for ensuring that you register your substance as part of the correct joint submission, and provide the correct substance identification information in your dossier. You must not copy or rely on information provided by the lead registrant (such as analytical or compositional information) but you need to make sure that the identification included in your dossier is specific for your substance. 

ECHA performs technical completeness checks to verify that substance identification information is correctly reported in Sections 1.1, 1.2 and 1.4 of IUCLID. 

Further manual verification is carried out for the following areas:


IUPAC name of the registered substance

When you submit your registration to ECHA, it needs to include the IUPAC name of your substance. The IUPAC name refers to the chemical nomenclature established by the International Union of Pure and Applied Chemistry (IUPAC).

If you cannot apply the IUPAC nomenclature to your substance, a chemical name of the substance must be provided. As part of the completeness check ECHA manually verifies that a IUPAC name or chemical name is provided in the submitted dossier.

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Composition of well-defined substances

Well-defined substances refer to:

  • mono-constituent substances in which one constituent is present at a concentration of at least 80 % and the impurities make up no more than 20 % (w/w);
  • multi-constituent substances in which several constituents are present at a concentration level between 10 % and 80 % (w/w).

You need to report the legal entity compositions of your well-defined substances in respect to these principles. If you need to exceptionally deviate from these principles, you must provide a scientifically fully-substantiated justification. ECHA will manually verify your justification as part of the completeness check.

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Manufacturing process description for UVCB substances

UVCB stands for unknown or variable composition, complex reaction products or of biological materials. Since it can be difficult to fully identify a UVCB substance, you need to include a description of its manufacturing process in your dossier for each legal entity composition reported in IUCLID.

The manufacturing process information typically consists of:

  • The identity and ratio of starting materials; 
  • a description of the relevant manufacturing steps in the order they occur (including information on the reaction steps or mechanisms); 
  • the relevant plant operating parameters applied to control the composition (for example, temperatures or pressures; solvents; catalysis types); 
  • extraction or isolation steps (if applicable); 
  • clean-up or purification steps (if applicable). 

If your substance is a petroleum substance, the following information must be reported in the manufacturing process description:

  • The source material from which the petroleum stream is obtained. 
  • The refinery processes applied to the source materials. This may include blending processes (blending to specification), for which specification described by an international standard (for example EN228, EN590) should be provided.
  • The description as to how the final fraction is collected (for example atmospheric distillation, distillate or residue fraction; vacuum distillation, distillate or residue fraction; solvent extraction, extract or raffinate phase).
  • Specification of the registered substance. Measured typical values of boiling point range and carbon number range need to be provided. If a stream is defined in its EC description by other parameters, for example viscosity, they also need to be provided. 

ECHA manually checks if the above elements are correctly included in the manufacturing process description.

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Composition of UVCB substances

The constituents for each reported composition of your UVCB substance must be provided in IUCLID Section 1.2. 

All constituents present at ≥10 % and constituents relevant for classification and labelling or assessing persistent, bioaccumulative or toxic (PBT) properties must be reported individually. Other constituents must be reported as far as possible as groups of constituents according to their chemical nature. 

In very rare cases in which it is not possible to report constituents or groups of constituents separately, you much include a scientifically fully-substantiated justification in your dossier.

ECHA manually checks your justification.

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Analytical information

To fulfil the REACH requirement on the analytical data, you must provide analytical information that enables your substance to be identified.

Analytical information that is relevant for both the identification and quantification purposes must be provided. Identification establishes the chemical identity of the constituents of the substance, while quantification is carried out to determine the concentration of the constituents in the composition.

In very rare cases, the quantification analysis may not be necessary for verifying the composition required to be reported in your dossier. If your substance belongs to these very rare cases, a justification must be provided for not submitting any quantification. The justification must be scientifically fully substantiated.

ECHA manually verifies that the justification is scientifically substantiated.

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