GB CLP REGULATORY UPDATE
The UK Health and Safety Executive (HSE) submitted WTO TBT notification G/TBT/N/GBR/113, proposing new or revised entries in the GB Mandatory Classification and Labelling List for 60 hazardous chemical substances. The proposal covers industrial chemicals, pesticide active substances and metal compounds, with particular attention to CMR and environmental hazard classifications. Companies supplying substances or mixtures to Great Britain should monitor the proposal and assess possible effects on classifications, Safety Data Sheets and labels.
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Key GB MCL Proposal Details at a Glance
| Area | Proposal | Business relevance |
|---|---|---|
| Regulatory instrument | WTO TBT notification G/TBT/N/GBR/113 | Proposes revisions to the GB Mandatory Classification and Labelling List |
| Substance scope | 60 hazardous chemical substances | Includes industrial chemicals, pesticide active substances and specific metal compounds |
| Classification focus | CMR, aquatic environmental hazards and other health hazards | May affect classifications, labels, SDSs and downstream regulatory controls |
| Proposed timeline | Expected adoption in Q2 2026 and mandatory application from Q4 2028 | Companies should monitor the final decision before implementing classification changes |
Regulatory Background
Since the UK officially left the EU on January 1, 2021, Great Britain—including England, Scotland and Wales—no longer directly applies the EU CLP Regulation. Instead, it implements the independent Regulation on Classification, Labelling and Packaging of Substances and Mixtures (GB CLP Regulation).
To ensure the proper functioning of the domestic market and safeguard human health and environmental safety, the UK established its own GB Mandatory Classification and Labelling List (GB MCL List).
Separately, SI 2026/484 revised the GB CLP administrative framework. From 21 May 2026, the standalone classification and labelling notification requirement for substances placed on the Great Britain market was removed. This administrative change does not remove suppliers' obligations to classify, label and package chemicals or apply legally binding GB MCL entries. Read more about the 2026 GB CLP notification changes.
Proposed GB MCL Implementation Timeline
This proposal is the result of a routine review under the UK's independent regulatory framework. According to the proposal, the new classification standards were expected to be officially adopted in the second quarter of 2026, with a transitional period provided for enterprises, and are scheduled for mandatory enforcement starting from the fourth quarter of 2028.
Key Revisions Affecting 60 Hazardous Substances
According to the technical document published by the HSE, this adjustment involves 60 substances, covering various industrial chemicals, pesticide active substances and specific metal compounds. The core changes focus primarily on the reclassification of Carcinogenicity, Reproductive toxicity and Mutagenicity (CMR), as well as hazards to the aquatic environment.
The following is a summary of some key substances and their proposed classifications.
CMR Substances (Carcinogenic, Mutagenic, Reprotoxic)
Trimethyl phosphate (CAS: 512-56-1): Proposed to be classified as Carcinogenicity 1B (Carc. 1B), Germ cell mutagenicity 1B (Muta. 1B), and Reproductive toxicity 1B (Repr. 1B).
Barium chromate (CAS: 10294-40-3): Proposed to be classified as Carcinogenicity 1B (Carc. 1B).
Boron compound series: Including sodium bromide, potassium bromide, magnesium metaborate and various other boron/bromine compounds, which are generally proposed to be classified as Reproductive toxicity 1B (Repr. 1B), accompanied by specific concentration limits.
2,3-epoxypropyl isopropyl ether (CAS: 4016-14-2): Proposed to be classified as Reproductive toxicity 1B (H360F).
Environmental Hazard Substances
Copper compound series: A large number of copper compounds, such as cuprous oxide, copper hydroxide and copper carbonate, are included in the list, mainly involving acute toxicity and serious hazards to the aquatic environment (Aquatic Acute 1 / Aquatic Chronic 1), with M-factors established for some substances, such as M=10 or M=100.
Other Substances of Concern
Industrial and agricultural chemicals: Isophorone diisocyanate (IPDI, CAS: 4098-71-9) and Folpet (CAS: 133-07-3) are also included in the adjustment, involving classifications for skin sensitisation, respiratory sensitisation and specific target organ toxicity.
Compliance Advice for Chemical Companies
In response to this GB CLP Regulation update, REACH24H suggests that relevant enterprises take the following measures:
Check product inventory: Compare product formulas to confirm whether they contain any of the 60 substances in the notification. Enterprises dealing with copper-based fungicides, boron-based flame retardants and phosphate additives should pay particular attention.
Review the public consultation record: The deadline for public comments on this notification was March 27, 2026. Companies should continue monitoring HSE and WTO updates concerning the proposal and subsequent decisions.
Update technical documentation in advance: For products confirmed to be affected, it is recommended to start updating SDSs and labels for the Great Britain market as early as possible after the regulation is officially adopted, to avoid logistical backlogs or compliance risks as the mandatory effective date approaches.
What the Proposal Means for GB Chemical Compliance
The independent operation of the UK GB CLP Regulation means that enterprises can no longer rely solely on EU ECHA classification data but must independently monitor the regulatory dynamics of the UK HSE.
The classification adjustment of these 60 substances is one of the key compliance tasks for 2026. REACH24H reminds industry colleagues to closely follow the subsequent legislative process to ensure the completion of all compliance transitions before mandatory enforcement in the fourth quarter of 2028.
How REACH24H Can Help
REACH24H can support companies in assessing the potential impact of GB MCL changes on substance portfolios, classification decisions, Safety Data Sheets and labels.
Regulatory monitoring: Track GB CLP and GB MCL proposals, decisions and implementation dates.
Substance scope screening: Review product compositions and identify substances potentially affected by new or revised GB MCL entries.
Hazard communication review: Assess classification, SDS and label implications through REACH24H's Global GHS, SDS/MSDS and Label Compliance support.
Great Britain market compliance: Coordinate related obligations through REACH24H's UK REACH compliance services.
Need support assessing the impact of proposed GB MCL changes?
REACH24H can help companies screen affected substances, review classification evidence and prepare compliant SDS and label updates for the Great Britain market.
Recommended Reading
2026 GB CLP Update Removes C&L Notification: What Chemical Suppliers Need to Know
UK Seventh Edition GB Mandatory Classification and Labelling List Released
