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

For definition of Groups, see Preamble Evaluation.

VOL.: 52 (1991) (p. 213)

CAS No.: 75-25-2

5.1 Exposure data

Bromoform has a limited number of industrial uses. It is also found in chlorinated drinking-water as a consequence of the reaction between chlorine, added during water treatment, and natural organic substances in the presence of bromide ion. Bromoform has been detected in chlorinated drinking-water in many parts of the world; it has also been detected in untreated water, but at lower levels. Bromoform is the major organohalide produced by chlorination of seawater during desalination. It is a major component of the organohalides produced by marine algae.

The major route of human exposure to bromoform is from drinking-water, although ambient air is also an important source of exposure in some areas.

5.2 Experimental carcinogenicity data

Bromoform was tested for carcinogenicity in a two-year study by oral gavage in male and female B6C3F₁ mice and Fischer 344 rats. It induced adenomatous polyps and adenocarcinomas of the large intestine in male and female rats. Bromoform did not increase the proportion of mice with tumours. In a screening test by intraperitoneal injection, there was a slight increase in the average number of lung tumours in strain A mice given the middle dose of bromoform.

5.3 Human carcinogenicity data

No relevant data were available to the Working Group.

5.4 Other relevant data

In experimental animals, bromoform induced liver and kidney damage and decreased the immune response.

There is some evidence of developmental toxicity in the absence of maternal toxicity in rats.

Mutagenic effects of bromoform were observed occasionally in bacteria. In single studies, bromoform induced mitotic arrest in plants, mutations in insects and in cultured mammalian cells and sister chromatid exchange in human lymphocytes. Chromosomal aberrations were induced in cultured mammalian cells. In single studies in rodents in vivo, bromoform did not bind to DNA or cause chromosomal aberrations. Sister chromatid exchange was induced in rodents in vivo.

5.5 Evaluation

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

There is limited evidence for the carcinogenicity of bromoform in experimental animals.

Overall evaluation

Bromoform is not classifiable as to its carcinogenicity to humans (Group 3).

For definition of the italicized terms, see Preamble Evaluation.

Subsequent evaluation: Vol. 71 (1999)

Synonyms

• Methenyl tribromide
• Methyl tribromide
• Tribromomethane

    See Also:
       Toxicological Abbreviations
       Bromoform (ICSC)
       Bromoform  (IARC Summary & Evaluation, Volume 71, 1999)