1. The supplier shall ensure that the label is updated, without undue delay, following any change to the classification and labelling of that substance or mixture, where the new hazard is more severe or where new supplemental labelling elements are required under Article 25, taking into account the nature of the change as regards the protection of human health and the environment. Suppliers shall cooperate in accordance with Article 4(9) to complete the changes to the labelling without undue delay.
2. Where labelling changes are required other than those referred to in paragraph 1, the supplier shall ensure that the label is updated within 18 months.