What are benzidine dyes?

Benzidine and its congeners are important precursors in the synthesis of dyes. 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.

Where benzidine dyes are found?

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.

Why is EPA concerned?

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

What EPA is doing?

• Current actions
  • December 17, 2014: EPA issued a final Significant New Use Rule under the Toxic Substances Control Act (TSCA) for nine benzidine-based dyes. This SNUR requires manufacturers (including importers) and processers of these nine benzidine-based chemical substances to notify EPA at least 90 days before starting or resuming new uses of these chemicals in any products, except for certain limited laboratory uses. This notification allows EPA the opportunity to evaluate the intended use and, if necessary, to prohibit or limit that activity.
    • Read the final SNUR
    • Fact sheet on benzidine-based dyes
    • Read the press release
• Previous actions
  • March 26, 2012: EPA issued a proposed SNUR to add nine benzidine-based substances.
    • Access the public comment docket for the Significant New Use Rule (SNUR) adding nine benzidine-based substances to the existing SNUR (Docket ID EPA-HQ-OPPT-2010-0573) on Regulations.gov
  • Download the complete Benzidine Dyes Action Plan
    • Access the public comment docket for the Benzidine Dyes Action Plan (Docket ID EPA-HQ-OPPT-2010-0570) on Regulations.gov
  • October 7, 1996: EPA issued a Significant New Use Rule for Benzidine-based Chemical Substances