Abstract
The aromatic amine HC Blue No. 1 is a hair colorant intended exclusively for use in hair dyes. While this colorant had previously been used in concentrations up to 1.6%, current information indicates it is not presently used in any hair dyes. Animal studies indicate this ingredient is absorbed slowly through the skin. Short-term and subchronic animal toxicity studies show a dose-dependent reduction in weight gain. HC Blue No. 1 was mutagenic in some, but not all, test systems, and was associated with fetal bone malformations when given orally to pregnant rats at levels that were maternally toxic. In a National Toxicology Program feeding study, dosed male rats had a positive trend in incidence of hepatic neoplastic nodules, but not in hepatic carcinomas; dosed female rats showed a positive trend in the incidence of alveolar/bronchiolar neoplasms; and mice of both sexes showed an increase in hepatocellular carcinomas. Although it is recognized that further dermal carcinogenicity data would help clarify the different findings in the current data, such information is not expected, and it is concluded on the basis of the data that are available in this report that HC Blue No. 1 is unsafe for use in cosmetic formulations (hair dyes).