Members of the 40-plus generation are not the only ones who change their hair color. The Cosmetic, Toiletry, and Fragrance Association estimates that close to two out of every five American women and a smaller number of men dye their hair. The decision to change hair color has recently become more complicated because some recent studies have linked hair coloring with an increased risk of contracting certain cancers. To make matters more confusing, other studies do not support those findings. Most hair dyes also don't have to go through pre-market testing for safety that other cosmetic color additives do before hitting store shelves.
Consumers are often on their own, consequently, when deciding whether hair dyes are safe.
Although the adulteration provision of the Food, Drug, and Cosmetic Act enables FDA to seek removal of a cosmetic from the market if it is shown to be harmful under conditions of use, hair colorings made from coal tar were given special exemption from such bans when the act was passed in 1938. The main ingredient in the coal-tar hair dyes manufactured at the time prompted an allergic reaction in some susceptible individuals. Fearing FDA would ban the sale of the hair dyes because some users might develop a rash or have other allergic reactions, the industry successfully lobbied before the act passed to get coal-tar hair dyes exempted from the adulteration provision. Manufacturers were required, however, to include a warning in the labels that the products can cause skin irritation in certain allergic individuals. Most hair dyes in use today derive their ingredients from petroleum sources, but have been considered coal-tar hair dyes by FDA because they contain some of the same compounds found in these older dyes.