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Benzidine Dyes

What chemicals are addressed in the action plan?

This Benzidine Dyes Action Plan (PDF)(12 pp., 85 KB, About PDF), released August 18, 2010, addresses 48 dyes derived from benzidine and its congeners, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine, and 3,3'-dimethoxybenzidine.

Why is EPA concerned about these chemicals?

Benzidine and its congeners are important precursors in the synthesis of dyes. Some of these dyes have the potential to metabolize to aromatic amines that are considered to be carcinogenic. Benzidine and dyes metabolized to benzidine are classified as known human carcinogens. Benzidine's congeners, 3,3'-dichlorobenzidine, 3,3'-dimethylbenzidine, and 3,3'-dimethoxybenzidine and dyes metabolized to the latter two congeners have all been classified as "reasonably anticipated to be human carcinogens."

Benzidine-based and congener-based dyes are used in the production of textiles, paints, printing inks, paper, and pharmaceuticals. These dyes have the potential to be leached from textiles, such as clothing, that are in prolonged contact with human skin. They are also used as reagents and biological stains in laboratories, are used in the food industries, and have more recent uses in laser, liquid crystal displays, ink-jet printers, and electro-optical devices.

Because these dyes have the potential to metabolize to carcinogenic amines both in and on the human body, EPA is concerned about the potential risk from exposure, including exposure of children, from using products containing benzidine and congener-based dyes.

EPA also reviewed benzidine congener-based pigments, but determined that the presence of the pigments in such consumer products as printing inks, paints, plastics and textiles was unlikely to present an exposure concern because the pigments are not bioavailable and are not absorbed into the body.

What action is EPA taking?

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