Gentian violet, leucogentian violet, malachite green, leucomalachite green, and CI Direct Blue 218

Abstract

This volume of the IARC Monographs provides evaluations of the carcinogenicity of three dyes and their two leucometabolites: gentian violet, leucogentian violet, malachite green, leucomalachite green, and CI Direct Blue 218.Gentian violet and malachite green are cationic triphenylmethane dyes widely used for textiles, paper, and acrylic products, as biological stains, and in some hair dyes and other cosmetics. Because of their antibacterial and antifungal properties, they have had various medical, veterinary, and aquaculture applications, including the treatment of livestock, animal feed, ornamental fish, and farmed fish and shellfish.Leucogentian violet and leucomalachite green are used as precursors in the production of their parent compounds and have direct applications as chromogenic reagents in analytical chemistry and as radiochromic indicators in dosimeters.CI Direct Blue 218 is a copper-chelated dimethoxybenzidine-based azo dye used for cellulose, acetate, nylon, silk, wool, tissue, fine papers, and textile goods.For all agents, data were sparse regarding exposure levels, but indicated that exposures can occur in occupational settings and in the general population.An IARC Monographs Working Group reviewed evidence from cancer bioassays in experimental animals and mechanistic studies to assess the carcinogenic hazard to humans of exposure to these agents and concluded that:Gentian violet, leucomalachite green, and CI Direct Blue 218 are possiblycarcinogenic to humans (Group 2B)Leucogentian violet and malachite green are not classifiable as to theircarcinogenicity to humans (Group 3).