Summary: About 33 million women use hair dyes to temporarily or permanently change their hair color. Most dyes marketed for use by women are known as coal tar hair dyes because initially coal tar was the only commercially practical source of material needed to synthesize the colors used in them. Most coal tar hair dyes contain colors derived from petroleum rather than coal tar. Because a color chemically identical to the petroleum-derived color could be derived from coal tar, the Food and Drug Administration (FDA) classifies petroleum-derived colors as coal tar colors and regulates hair dyes containing them accordingly. Coal tar hair dyes whose labeling contains a prescribed statutory warning concerning possible skin irritation and blindness are exempt from Federal Food, Drug, and Cosmetic Act provisions concerning adulteration, but they are not exempt from misbranding provisions of the act.
Exemptions in the act do not permit FDA to regulate coal tar hair dye products effectively; they bar the agency from banning or restricting the use of cancer-causing coal tar hair dyes. Although coal tar hair dyes are subject to FDA labeling requirements, the agency has not used this authority to require a cancer warning on labels of dyes containing known human or animal carcinogens. Colors known to cause or suspected of causing cancer reportedly are being used in all three types of coal tar hair dyes. Data indicate that the cancer-causing coal tar hair colors may be absorbed through the skin and scalp. Colors that may be used in some temporary and semipermanent hair dyes are derived from benzidine, a known carcinogen; they may be a significant cancer risk because the colors may break down to benzidine in the human body. Nine color additives banned for use in cosmetics other than coal tar hair dyes are listed in the Cosmetic Ingredient Dictionary as available for use in coal tar hair dyes.
