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

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 63 (1995) (p. 431)
CAS No.: 271-89-6
Chem. Abstr. Name: Benzofuran

5. Summary and Evaluation

5.1 Exposure data

Benzofuran is produced by isolation from coal-tar oils, which are obtained as by-products of coking coal. Its major use is in the production of coumarone-indene resins. Human exposure can occur during coke production, coal gasification, the production of coumarone-indene resins or the combustion of coal and from tobacco smoke.

5.2 Human carcinogenicity data

No data were available to the Working Group.

5.3 Animal carcinogenicity data

Benzofuran was tested for carcinogenicity by oral administration in one study in mice and in one study in rats. In mice, benzofuran increased the incidence of hepatocellular adenomas in animals of each sex and of hepatoblastomas and forestomach papillomas and carcinomas in males; the incidence of alveolar-bronchiolar adenomas was increased in both males and females. Female rats had an increased incidence of renal-cell adenocarcinomas, which occur rarely in animals of this sex.

5.4 Other relevant data

No data were available on the toxicokinetics of benzofuran. Repeated administration of benzofuran to rats and mice caused renal toxicity; rats also developed slight hepatic toxicity.

Induction of gene mutation, sister chromatid exchange and chromosomal aberrations was seen in cultured rodent cells treated with benzofuran in single studies. Benzofuran was not mutagenic to bacteria.

5.5 Evaluation

There is inadequate evidence in humans for the carcinogenicity of benzofuran.

There is sufficient evidence in experimental animals for the carcinogenicity of benzofuran.

Overall evaluation

Benzofuran is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.


Last updated 05/27/1997

    See Also:
       Toxicological Abbreviations
       Benzofuran (ICSC)