AZO Pigments: Azo pigments consist of colorless particles (typically earths or clays) colored using an azo compound. Azo pigments are important in a variety of paints including artist’s paints. They have excellent coloring properties, mainly in the yellow to red spectrum.
Many azo pigments are non-toxic, although some, such as dinitroaniline orange, ortho-nitroaniline orange, or pigment orange 1, 2, and 5 have been found to be mutagenic. Several case studies have linked azo pigments with basal cell carcinoma.
Azo dyes derived from benzidine are carcinogens; exposure to them has classically been associated with bladder cancer. The production of benzidine azo dyes was discontinued in the 1980s “in the most important western industrialized countries”.
Consumer goods which contain listed aromatic amines originating from azo dyes were prohibited from manufacture and sale in European Union countries in September 2003.