Methylenedianiline and Its Dihydrochloride

4,4′-Methylenedianiline (MDA) (CAS 101-77-9) and its dihydrochloride (CAS 13552-44-8) are synthetic compounds used in different industrial processes. The main way of exposition occurs during their production and during their use in the polyurethane industry (occupational exposure), with dermal absorption after contact with contaminated surfaces being the most important route of exposure. Most of the toxic effects of these compounds are associated with metabolic intermediates formed after enzymatic N-oxidation that react with DNA, RNA, and proteins. Concerning carcinogenicity, MDA is included in Group 2B (possibly carcinogenic to humans).