Survey on hazardous non-regulated aromatic amines as cleavage products of azo dyes found in clothing textiles on the Swiss market

Azo dyes represent the most widely used chemical class of dyes in textiles. They may be biotransformed into aromatic amines by human skin bacteria. These aromatic amines might then enter the body through dermal absorption. Twenty-two aromatic amines are known carcinogens. Therefore, azo dyes are banned for the use in textiles for clothing in the European Union. Non-regulated aromatic amines with suspected toxic properties might also be released by azo dyes. For this survey, 58 aromatic amines of toxicological concern were selected, including the 22 regulated as well as aromatic amines suspected of being mutagenic and some of their positional isomers. Their occurrence and content after the reductive cleavage of the azo bond were investigated in 150 random textile samples from Swiss retail outlets and online shops. Substances suspected of being mutagenic, including potential reduction derivates of nitro compounds were detected in relevant concentrations (> 30 mg/kg) in 25% of the analyzed samples. This survey clearly shows that a substantial percentage of the azo dyes used in today’s textiles for cloth are made up of aromatic amines possessing mutagenic and/or other hazardous properties.