GB CLP REGULATORY UPDATE
The UK Health and Safety Executive (HSE) has published the Seventh Edition of the GB Mandatory Classification and Labelling List, introducing new or revised legally binding classifications for 30 chemical substances. The entries took effect on 23 September 2025, with a final compliance date of 23 March 2027. Suppliers placing affected substances or mixtures on the Great Britain market should review product classifications and prepare any necessary Safety Data Sheet and label updates.
Quick Navigation
Jump to the key sections of this article.
Seventh Edition GB MCL List at a Glance
| Item | Seventh Edition update | What suppliers should consider |
|---|---|---|
| Regulatory scope | New or revised mandatory classifications for 30 substances | Screen substance and mixture portfolios against the updated list |
| Entry into force | 23 September 2025 | Use the transition period to assess affected products and supply chains |
| Compliance date | 23 March 2027 | Complete required classification, SDS and label changes before the deadline |
| Other revisions | Corrections, duplicate removal and updates to certain SCLs and ATEs | Do not limit the review to newly listed substance names |
What Is the GB Mandatory Classification and Labelling List?
Since 1 January 2021, following Brexit, Great Britain—England, Scotland and Wales—has operated an independent classification and labelling framework under the GB CLP Regulation rather than directly applying the EU CLP Regulation.
The GB Mandatory Classification and Labelling List, managed by HSE as the GB CLP Agency, contains legally binding classifications and accompanying hazard labelling for substances placed on the Great Britain market. Where a substance has a GB MCL for one or more hazard classes, suppliers must apply that mandatory classification. Other hazard classes not covered by an MCL may still require self-classification.
The Seventh Edition GB MCL requirements should be distinguished from the later administrative changes introduced by SI 2026/484. From 21 May 2026, affected suppliers no longer need to submit standalone C&L notifications to HSE, but the mandatory classifications in the GB MCL List remain legally binding. See what the 2026 GB CLP update means for chemical suppliers.
Key Updates in the Seventh Edition GB MCL List
The Seventh Edition incorporates new or revised GB mandatory classifications for 30 substances included in the fifth recommendation made to ministers by the GB CLP Agency and subsequently accepted in September 2025. The update also corrects editorial issues and classification inconsistencies in earlier entries, removes duplicates and revises certain Specific Concentration Limits (SCLs) and Acute Toxicity Estimates (ATEs).
Examples of Substance Classification Updates
Sodium perborate and disodium perborate: Classified as reproductive toxicants, Repr. 1B, requiring the corresponding mandatory hazard communication.
Ozone: Classified as Oxidising Gas Category 1 and Acute Toxicity Category 1, with additional hazard classifications relating to the nervous and respiratory systems.
Pigment Red 83 and Solvent Violet 13: Substances used in applications including tattoo inks and cosmetics, classified as Skin Sensitisation Category 1B.
Corrections and Technical Adjustments
Editorial corrections: Spelling errors and classification inconsistencies in earlier entries were corrected.
Duplicate removal: Duplicate entries were removed to improve the accuracy and consistency of the list.
Technical values: Certain SCLs and ATEs were updated to better reflect the substances’ hazard profiles.
What the Seventh Edition Means for Chemical Suppliers
The updated classifications may affect substances and mixtures supplied across sectors including cosmetics, general chemicals, plant protection products, coatings, pharmaceuticals and industrial manufacturing. Businesses should determine whether affected substances are present in their portfolios and whether the revised entries change existing mixture classifications or hazard communication.
Classification and Supply Chain Review
Where an affected substance has a new or revised GB MCL, suppliers must apply the legally binding classification for the hazard classes covered. Formulators should also assess whether the change affects the classification of mixtures containing that substance and communicate relevant changes across the supply chain.
Safety Data Sheet and Label Updates
Affected companies may need to revise Safety Data Sheets and labels to reflect updated hazard categories, hazard statements, signal words, pictograms and precautionary measures. REACH24H’s Global GHS, SDS/MSDS and Label Compliance support can assist companies with market-specific hazard communication reviews.
Ongoing GB MCL Developments
The GB MCL List continues to evolve independently from EU harmonised classification and labelling. Companies should therefore monitor HSE decisions in addition to EU developments. A subsequent proposal covering 60 substances illustrates the continuing pace of change; see the REACH24H analysis of the proposed GB MCL revisions for 60 chemical substances.
Recommended Compliance Actions Before March 2027
Companies supplying substances or mixtures to Great Britain should use the transition period to complete the following actions:
Screen substance inventories: Compare raw materials and product formulations against the Seventh Edition GB MCL List, including both new and revised entries.
Reassess mixture classifications: Determine whether revised component classifications, SCLs or ATEs change the classification of any mixtures.
Update Safety Data Sheets: Revise applicable hazard classifications, hazard statements, exposure controls and other affected SDS sections.
Review labels and packaging: Confirm whether pictograms, signal words, hazard statements, precautionary statements or packaging measures require adjustment.
Coordinate supply chain implementation: Communicate changes to suppliers, importers, downstream users and distributors, and manage existing stock and relabelling plans.
Complete the transition on time: Ensure affected products comply with the Seventh Edition requirements by 23 March 2027.
How REACH24H Can Help
REACH24H can support companies in assessing the effects of GB MCL updates on substance portfolios, mixture classifications and hazard communication documents.
Substance scope screening: Identify products potentially affected by new or revised GB MCL entries.
Classification assessment: Review the implications of mandatory classifications, SCLs and ATEs for substances and mixtures.
SDS and label compliance: Prepare or review Great Britain-specific Safety Data Sheets and labels.
Regulatory monitoring: Track further GB CLP and GB MCL decisions, transition periods and implementation dates.
Related market access support: Coordinate classification work with relevant UK REACH compliance obligations.
Need support preparing for the Seventh Edition GB MCL deadline?
REACH24H can help screen affected substances, assess classification changes and prepare compliant Safety Data Sheets and labels for the Great Britain market.
Recommended Reading
2026 GB CLP Update Removes C&L Notification: What Chemical Suppliers Need to Know
UK Proposes GB MCL List Revisions for 60 Chemical Substances
