25 new substances added to Great Britain Mandatory Classification and Labelling List

On 12 March 2024, the UKs Health and Safety Executive (HSE) announced that 25 chemical substances have been added to the Great Britain Mandatory Classification and Labelling List (GB MCL). These additions came into force on 2 March 2025 and summaries have been published in the GB CLP publication table. The compliance date for the 25 substances is 2 September 2025. The additions were made after the Secretary of State accepted HSE’s recommendations, with the agreement of the Scottish and Welsh Ministers. The GB MCL list now contains a total of 123 entries.

Scientific Basis

The inclusion of these substances is based on the scientific and technical evaluations that identified the intrinsic hazards of these 25 substances. Whilst the HSE’s technical reports highlighted these intrinsic hazards, the impact and policy assessments set out in the Agency's opinions did not identify any significant impacts.

Post-Brexit Additions to the GB MCL

This is the second batch of substances to be added to the GB MCL after Brexit. The first batch of 98 substances was added on 20 October 2023. The HSE notified the World Trade Organization (WTO) of its intention to add this second batch on 24 August 2023. A list of the substances can be found here.