International Agency for Research on Cancer (IARC) - Summaries & Evaluations

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 57 (1993) (p. 235)
CAS No.: 2429-74-5
Chem. Abstr. Name: 3,3'-[(3,3'-Dimethoxy[1,1'-biphenyl]-4,4'-diyl) bis(azo)]bis[5-amino-4-hydroxy-2,7-naphthalenedisulfonic acid], tetrasodium salt

5. Summary of Data Reported and Evaluation

5.1 Exposure data

CI Direct Blue 15, a bis-azo dye derived from 3,3'-dimethoxybenzidine, is used mainly for dyeing textiles and paper. The technical grade contains about 50% of pure dye, in addition to inorganic salts and a mixture of about 35 organic compounds, including 3,3'-dimethoxybenzidine.

5.2 Human carcinogenicity data

No data were available to the Working Group.

5.3 Animal carcinogenicity data

Technical-grade CI Direct Blue 15 was tested for carcinogenicity in one study in rats by administration in the drinking-water. It produced benign and malignant tumours of the skin, Zymbal gland, liver, small intestine and oral cavity as well as leukaemia in animals of each sex, of the large intestine and preputial gland in males and of the uterus and clitoral gland in females.

5.4 Other relevant data

CI Direct Blue 15 caused renal and hepatic toxicity in rats. Reductive cleavage of the azo bonds to yield 3,3'-dimethoxybenzidine was demonstrated in vivo.

CI Direct Blue 15 induced mutation in bacteria under conditions that favour reduction. Neither sister chromatid exchange nor chromosomal aberrations were induced in cultured mammalian cells.

5.5 Evaluation

There is inadequate evidence in humans for the carcinogenicity of CI Direct Blue 15.

There is sufficient evidence in experimental animals for the carcinogenicity of technical grade CI Direct Blue 15.

Overall evaluation

CI Direct Blue 15 is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.


Last updated 08/22/1997

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       Toxicological Abbreviations