para-PhenyleneDiamine (PPD) is a widely used chemical in almost all hair dye formulations. This compound is also used as a photographic developing agent and as an intermediate in the manufacture of azo dyes, antioxidants, and accelerators for rubber vulcanization.
Acute (short-term) exposure to high levels of p-phenylenediamine may cause severe dermatitis, eye irritation and tearing, asthma, gastritis, renal failure, vertigo, tremors, convulsions, and coma in humans.