Look for P-PHENYLENEDIAMINE in hair dyes and colors identified as “C.I.” followed by five digits in other products. Potential to cause cancer and can be contaminated with heavy metals toxic to the brain.
Coal tar-derived colors are used extensively in cosmetics, generally identified by a five-digit Color Index (C.I.) number. The U.S. color name may also be listed (“FD&C” or “D&C” followed by a color name and number). P-phenylenediamine is a particular coal tar dye used in many hair dyes. Darker hair dyes tend to contain more phenylenediamine than lighter colors.
Health and Environmental Hazards
Coal tar is a mixture of many chemicals, derived from petroleum, Coal tar is recognized as a human carcinogen and the main concern with individual coal tar colors (whether produced from coal tar or synthetically) is their potential to cause cancer. These colors may as well be contaminated with low levels of heavy metals and some are combined with aluminum substrate. Aluminum compounds and many heavy metals are toxic to the brain. Some colors are not approved as food additives, yet they are used in cosmetics that may be ingested, like lipstick. (In the U.S. color naming system, “FD&C” indicates colors approved by the U.S. Food and Drug Administration for use in foods, drugs, and cosmetics. “D&C” colors are not approved for use in food.)
P-phenylenediamine has been linked to tumours in laboratory tests conducted by the U.S. National Cancer Institute. A review of the epidemiologic literature confirmed statistically significant associations between hair dye use and development of several types of cancer although the authors concluded that the evidence was insufficient to determine that the hair dyes had caused the cancers. A separate study found that women who used hair dyes — especially over extended periods — had an increased risk of developing non-Hodgkin’s lymphoma (cancer of the lymph system). However, there is conflicting evidence, with other research suggesting no strong association between cancer and hair dye use. The International Agency for Research on Cancer therefore concluded that personal use of hair dyes is currently “not classifiable as to its carcinogenicity in humans.” The European Union classifies p-phenylenediamine as toxic (in contact with skin, by inhalation, or if swallowed), and as very toxic to aquatic organisms, noting that it may cause long-term adverse effects in the aquatic environment.
Several coal tar dyes are prohibited on Health Canada’s Cosmetic Ingredient Hotlist and Canada’s Cosmetic Regulations prohibit all but seven of these colors in eye makeup and other products used in the area of the eye. However, dozens of coal tar-derived colors are still widely used in other cosmetics. Some have been flagged for future assessment under the government’s Chemicals Management Plan.