There is no explicit legal obligation for registrants to update their registration dossier every time an import is made from a new non-EU source. However, according to Article 22(1)(b) of REACH, there is a legal obligation to update the composition of the substance as given in Section 2 of Annex VI. The registrant has to assess the sameness of the substance every time an import of the substance is made from a new source, according to Guidance for identification and naming of substances available on the ECHA website.
There are three possible outcomes of this assessment:
1. Registrants find that the substance has the same impurity profile as previous imports and is already registered by them. They do not have to update the registration dossier for the substance.
2. Registrants find that the substance has a different impurity profile from previous imports. They then have to update the relevant sections of the registration dossier (e.g. concentration ranges or changes in C&L) with the new composition of the substance.