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


VOL.: 30 (1983) (p. 207)

CAS No.: 52-68-6
Chem. Abstr. Name: Phosphoric acid, (2,2,2-trichloro-1-hydroxyethyl)-, dimethyl ester

5. Summary of Data Reported and Evaluation

5.1 Experimental data

Trichlorfon was tested for carcinogenicity by oral administration in mice and rats, by intraperitoneal administration in mice, rats and hamsters, by dermal application in mice and by intramuscular administration in rats. The studies in mice and two of the studies in rats were considered inadequate for evaluation. The other studies in rats and that in hamsters were not indicative of a carcinogenic effect.

Trichlorfon was teratogenic to mice, rats and hamsters when given at dose levels which also caused reductions in maternal food intake and maternal body weight gain.

There is sufficient evidence that trichlorfon or its degradation products is mutagenic in bacteria, mammalian cells and mice. Inconsistent results have been reported with many systems, however, and the instability of trichlorfon may be an important consideration in interpreting these data.

5.2 Human data

Trichlorfon was introduced in 1952. Its use as an insecticide in agricultural applications is a potential source of exposure, both of workers and of the general population. Its use in human medicine as an anthelmintic is another possible source of human exposure.

No data were available to evaluate the teratogenic effects of trichlorfon in humans. The available data were insufficient to evaluate the chromosomal effects of trichlorfon in humans.

No case report or epidemiological study of the carcinogenicity of trichlorfon alone was available to the Working Group. (See, however, the section 'Cancer Epidemiology of Pesticide Manufacturers, Users and Formulators', in this volume.)

5.3 Evaluation

The available data, while providing no evidence that trichlorfon is carcinogenic to mice or rats, were considered inadequate to evaluate the carcinogenicity of this compound to experimental animals. In view of its mutagenicity, confirmed in several experimental systems, further studies on the carcinogenicity of this compound are warranted. The Working Group was aware that a long-term bioassay was in progress.

No data on humans were available.

The available data are insufficient to evaluate the carcinogenicity of trichlorfon to humans.

Subsequent evaluation: Suppl. 7 (1987) (p. 73: Group 3)


Last updated: 16 April 1998

    See Also:
       Toxicological Abbreviations
       Trichlorfon (EHC 132, 1992)
       Trichlorfon (HSG 66, 1991)
       Trichlorfon (JECFA Food Additives Series 51)
       Trichlorfon (WHO Food Additives Series 45)
       TRICHLORFON (JECFA Evaluation)
       Trichlorfon (WHO Pesticide Residues Series 1)
       Trichlorfon (WHO Pesticide Residues Series 5)
       Trichlorfon (Pesticide residues in food: 1978 evaluations)