Final Report On the Safety Assessment of Hc Orange No. 11

HC Orange No. 1 is used as a colorant in semipermanent hair dyes. The highest concentration reported to be used is 0.15%, but information from manufacturers suggested that higher concentrations may be used in the future. Skin penetration through cadaver skin was 1.28% at 24 hours. In studies using rats, acute oral exposure studies produced little toxicity, and short-term toxicity studies produced reduced body weight and increased liver and kidney weights, relative to controls in animals fed 0.5% HC Orange No. 1. There was no evidence of reproductive or developmental toxicity in rats fed up to 1.25% HC Orange No. 1 or in a multigeneration study using rats in which 0.15% HC Orange No. 1 was painted on the skin. While evidence suggests this ingredient is a mild ocular irritant, no skin irritation, sensitization, or photosensitization was seen in animal or clinical tests. The preponderance of data (four out offive studies) indicate that this ingredient is not genotoxic. Hepatocellular and parathyroid hyperplasia were noted in the dermal carcinogenicity study, but the overall findings were clearly negative. Because the highest concentration tested that produced no significant sensitization in clinical tests was 3%, the Expert Panel concluded that safety could be assured only at levels ≤3%. The Expert Panel recognized that this concentration may be greater than that currently used in hair dye formulations.