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Benzidine Dyes Action Plan Summary

What chemicals are addressed in the action plan?

This action plan, 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?

On the basis of existing information, EPA included the the following actions in its action plan:

  1. Initiate rulemaking to add four benzidine-based dyes to an existing TSCA section 5(a)(2) significant new use rule (SNUR) for benzidine-based substances at 40 CFR 721.1660. A SNUR requires manufacturers who intend to use a chemical for the identified significant new use to submit an application to the Agency for review prior to beginning that activity.


    • March 26, 2012: EPA issued a proposed SNUR to add nine benzidine-based substances (the four noted in the action plan plus five others found on the agency’s Confidential Business Information Inventory of Chemicals) to the existing SNUR for benzidine-based substances. EPA will accept comments on the proposal until 60 days after publication in the Federal Register. Read the press release.

  2. Initiate rulemaking to establish a new TSCA section 5(a)(2) SNUR for benzidine congener-based dyes, including 44 specific such dyes.


  3. Consider proposing to eliminate the article exemption applied to SNURs to address potential concerns for exposure to these dyes on imported finished textiles.


  4. Consider initiating action under TSCA section 6, if EPA learns that these dyes are present in imported finished textiles. EPA has proposed eliminating the article exemption as part of the proposed SNUR for benzidine-based substances (61 p., 221 kb.) About PDF) issued on March 20, 2012 .


  5. Consider additional regulatory action, if EPA determines that there are other ongoing uses for these dyes and needs to obtain information necessary to determine whether those uses present concerns which need to be addressed.

Download the complete Benzidine Dyes Action Plan (PDF), (12 pp., 85 KB, About PDF)

Access the public comment docket for the Benzidine Dyes Action Plan (Docket ID EPA-HQ-OPPT-2010-0570) on Regulations.gov.

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.


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