The United Nations has adopted the 11th revision of the Globally Harmonised System of Classification and Labelling of Chemicals (GHS), introducing a new hazard class for global warming and major labelling changes. Adopted in December 2024 and effective globally from September 2025, GHS Rev. 11 affects all sectors handling chemicals—particularly manufacturers, transporters, and downstream users—by expanding hazard definitions and compliance duties.
New Climate Hazard Class Targets Global Warming Potential
A key feature of GHS Rev. 11 is the inclusion of a new classification: “Hazardous by contributing to global warming”. Substances or mixtures containing at least 0.1% of an ingredient listed under the Montreal Protocol with a Global Warming Potential (GWP) must now be classified and labelled accordingly.
This follows growing global policy alignment on climate risk, and marks a shift towards recognising environmental hazards beyond ozone depletion. Label elements include the signal word Warning and hazard statement “Harms public health and the environment by contributing to global warming”.
New Guidance on Non-Animal Testing for Skin Sensitisation
Chapter 3.4 has been substantially updated to support non-animal methods for classifying skin sensitisers. The revised guidance covers in vitro, in chemico, and defined approaches for both substances and mixtures, backed by OECD protocols. These developments reflect regulatory and ethical pressure to reduce animal testing in chemical safety.
The guidance details acceptable use cases for defined approaches and human data sources, from patch testing to epidemiological studies, offering greater flexibility in proving sensitisation potential.
Aerosols, Asphyxiants, and Precautionary Labelling Overhaul
GHS Rev. 11 refines classification rules for aerosols and chemicals under pressure, addressing sector-specific interpretations in areas such as transport. It also introduces a new Annex 11 section on *simple asphyxiants*—gases that displace oxygen in confined spaces.
Precautionary labelling has been restructured with updated statements (e.g., P320–P323) to improve usability. These changes support faster hazard recognition and more effective first-aid response.
Who Is Affected and What Comes Next?
The changes in GHS Rev. 11 apply globally and affect anyone involved in the production, handling, import, export, or regulation of chemicals. Stakeholders include not only chemical manufacturers but also logistics firms, retailers, regulators, and EHS professionals.
Implementation begins in September 2025. Compliance planning—including label and SDS updates—should begin now to avoid supply chain disruptions and regulatory penalties.
