3a-methyl-5,6,7,7a-tetrahydro-4H-isobenzofuran-1,3-dione

Methylhexahydrophthalic anhydride is an epoxy hardener, irritant to skin and mucous membranes. It is included in nondiglycidyl-ether-of-bisphenol-A epoxy resins. It can induce both allergic contact dermatitis and immunologic contact urticaria. It is structurally close to methyltetrahydrophthalic anhydride, which can also cause sensitization.