Topic summary
Hair dye

Extracted from the Wikipedia article Hair coloring.
Legal restrictions
Hair dyes are cosmetic compounds that make contact with the skin during application. Because of this skin contact, there exists some health risk associated with use of hair dyes. Thus, hair dyes are regulated in the commercial marketplace and, as new toxicity data is generated for some hair dyes and health risks are discovered, some of these hair dyes are being legally restricted from the cosmetic marketplace.