ECHA will update their list number format from a numerical to an alphanumerical format in early summer 2025.

This list number format is used for the list numbers that are used to identify registered or notified substances that don’t possess an EC-number. These list numbers will be assigned automatically by REACH-IT and are technical identifiers without any legal significance.

List numbers that were assigned before the format change will not be affected by this change.

Further information is available on ECHA’s press release.