Question: are azo dyes safe to use?
Answer: Safety and regulation Many azo pigments are non-toxic, although some, such as dinitroaniline orange, ortho-nitroaniline orange, or pigment orange 1, 2, and 5 are mutagenic and carcinogenic. Azo dyes derived from benzidine are carcinogens; exposure to them has classically been associated with bladder cancer.