The United Kingdom is progressing with significant regulatory changes to the Great Britain Mandatory Classification and Labelling (GB MCL) system for hazardous chemicals. The proposed approach aims to ensure that the classification and labelling of chemicals placed on the United Kingdom market are regularly reviewed in light of new scientific information and regulatory developments.
Following Brexit, chemical classification and labelling in the United Kingdom (England, Scotland and Wales) is governed by the GB CLP Regulation, which operates separately from the EU CLP Regulation. The Health and Safety Executive (HSE) acts as the GB CLP Agency, while Northern Ireland continues to follow the EU CLP framework.
Under the new system, the introduction of a new GB MCL or revision of an existing classification will follow a structured process. This includes a GB MCL proposal, public consultation, scientific and technical assessment, impact and policy assessment, an HSE Agency Opinion, ministerial recommendation and final decision. Once approved, the relevant classification is incorporated into the legally binding GB MCL List.
Particular attention is given to priority hazards such as carcinogenicity, germ cell mutagenicity, reproductive toxicity and respiratory sensitisation. Where new scientific information indicates that an existing mandatory classification may need to be revised, United Kingdom-based manufacturers, importers and downstream users may be required to submit a new or revised GB MCL proposal to HSE.
In parallel, the UK introduced further changes to its GB CLP framework in 2026. As of 21 May 2026, the requirement to notify HSE of classification and labelling information for substances placed on the United Kingdom market was removed. However, businesses remain responsible for ensuring that substances and mixtures are correctly classified, labelled and packaged before being placed on the United Kingdom market.
One important consequence of the new system is the possibility of increasing divergence between the UK and EU classification systems. HSE has confirmed that the United Kingdom may establish its own mandatory classifications based on scientific evidence and wider policy considerations. As a result, the same substance may eventually have different mandatory classifications under the EU CLP and GB CLP frameworks.
This development is particularly relevant for companies supplying chemicals or chemical-containing products to the UK market. Monitoring EU harmonised classifications alone may no longer be sufficient, as businesses must also monitor the GB MCL List and GB CLP requirements. Changes to mandatory classifications may have downstream implications for product labels, Safety Data Sheets (SDS), packaging and supply-chain communication. The classifications included in the GB MCL List are legally binding.
For the cosmetics and personal care sector, these developments further underline the importance of regularly reviewing the GB CLP status of substances used in formulations. Where the hazard classification of an ingredient changes, companies may need to reassess relevant safety and labelling documentation.
As the UK continues to develop its own GB MCL framework independently from the EU CLP system, companies operating across both markets should ensure that EU and UK requirements are assessed separately to maintain regulatory compliance.