ECHA Opens Organic Anhydride Hazard Classification Consultation

Organic Anhydride Classification Proposals Cover Nine Consultation Entries

The European Chemicals Agency (ECHA) has opened an organic anhydride classification consultation covering nine substance/group entries under the Classification, Labelling and Packaging (CLP) Regulation. Comments opened on 21 September and close on 20 November 2026.

The consultation entries are:

• 1,2,3,6-tetrahydromethyl-3,6-methanophthalic anhydride and individual isomers or combinations thereof, including CAS 25134-21-8, 828-66-0 and 53584-57-9
• chlorendic anhydride, CAS 115-27-5
• 4-chloroformylphthalic anhydride, CAS 1204-28-0
• 4,4'-biphthalic dianhydride, CAS 2420-87-3
• 4,4'-oxydiphthalic anhydride, CAS 1823-59-2
• 5,5'-sulfonyldi(2-benzofuran-1,3-dione), CAS 2540-99-0
• benzophenone-3,3':4,4'-tetracarboxylic dianhydride, CAS 2421-28-5
• ethylene bis[1,3-dihydro-1,3-dioxo-isobenzofuran-5-carboxylate], CAS 1732-96-3
• tetrabromophthalic anhydride, CAS 632-79-1

Respiratory and skin sensitisation are open for comment for all nine. Additional hazard classes open for comment include acute oral or inhalation toxicity, skin corrosion or irritation, serious eye damage or irritation, carcinogenicity, germ-cell mutagenicity and specific target organ toxicity after single exposure. An endpoint being open for comment does not establish that the submitter proposes classification for that endpoint.

No Immediate CLP Label Change Follows From Consultation

The consultation does not amend Annex VI to the CLP Regulation. Current harmonised classifications and suppliers' self-classification duties remain in force. After consultation, ECHA's Committee for Risk Assessment may adopt opinions. The European Commission may then adopt a delegated act, subject to European Parliament and Council scrutiny, with its own legal dates.