Acid Dye - Health and Safety

Health and Safety

Any dyes including acid dyes have the ability to induce sensitization in humans due to their complex molecular structure and the way in which they are metabolized in the body. This is extremely rare nowadays as we have a much greater understanding through experience and knowledge of dyestuffs themselves. Some acid dyes are used to color food. We wear fabrics every day exposing our skin to dyes.

The greatest risk of disease or injury due to dyes is by ingestion or exposure to dye dust. These scenarios are normally confined to textile workers. Whereby the dye itself is normally nontoxic, the molecules are metabolized (usually in the liver) where they may be broken back down to the original intermediates used in manufacture. Thus many intermediate chemicals used in dye manufacture have been identified as toxic and their use restricted. There is a growing trend among governments to ban the importation of dyes synthesized from restricted intermediates. For example: the dye CI Acid red 128 is banned in Europe as it was found to metabolize in the body back to ortho-toluidine, one of its chemical intermediates. Many intermediates used in dye manufacture such as ortho-toluidine, benzidine etc. were found to be carcinogenic. All the major chemical companies have now ceased to market these dyes. Some, however, are still produced but they are found to be totally safe when on the fiber in its final state. The use of these dyes is declining rapidly as cheap and safer alternatives are now easily available.

The incident concerning the dye Sudan 1 is an example of a suspected toxic dye finding its way into the food chain. Such incidents are extremely rare.