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

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 71 (1999) (p. 629)

CAS No.: 106-88-7
Chem. Abstr. Name: Ethyloxirane

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Exposure to 1,2-epoxybutane may occur in its production and use as a monomer, chemical intermediate and stabilizer.

5.2 Human carcinogenicity data

No data were available to the Working Group.

5.3 Animal carcinogenicity data

1,2-Epoxybutane was tested for carcinogenicity by inhalation exposure in one study in mice and in one study in rats, producing nasal papillary adenomas in rats of both sexes and pulmonary alveolar/bronchiolar tumours in male rats. It did not induce skin tumours when tested by skin application in one study in mice.

5.4 Other relevant data

1,2-Epoxybutane induced morphological transformation, sister chromatid exchanges, chromosomal aberrations and mutation in cultured animal cells; however, in a single study, it did not induce unscheduled DNA synthesis in rat primary hepatocytes. It induced sex-linked recessive lethal mutations and translocations in Drosophila melanogaster, mitotic recombination in yeast, and mutations in yeast and fungi. 1,2-Epoxybutane induced DNA damage and mutations in bacteria.

5.5 Evaluation

No epidemiological data relevant to the carcinogenicity of 1,2-epoxybutane were available.

There is limited evidence in experimental animals for the carcinogenicity of 1,2-epoxybutane.

Overall evaluation

1,2-Epoxybutane is possibly carcinogenic to humans (Group 2B).

In making the overall evaluation, the Working Group took into consideration that 1,2-epoxybutane is a direct-acting alkylating agent which is mutagenic in a range of test systems.

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluation: Vol. 47 (1989)


Last updated: 13 April 1999

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       Toxicological Abbreviations