The unique formula identifier (UFI) is used for the identification of mixtures in the CLP Regulation, Annex VIII. At least one UFI is required for every mixture for which a harmonised notification for the Poison Information Centres has to be carried out. A mixture can have several UFIs, but a UFI cannot be associated with several mixtures. If a mixture is changed too much (exact definition: Annex VIII, Part B, 4.1), then the mixture requires a new UFI / new UFIs. UFIs can already be created and assigned. However, they will only be mandatory for European notifications from 2020.