1. Exposure Data

1.1. Chemical and physical data

1.1.1. Nomenclature

• Chem. Abstr. Serv. Reg. No.: 868-85-9
• Chem. Abstr. Name: Dimethyl phosphonate

1.1.2. Structural and molecular formulae and relative molecular mass

1.1.3. Physical properties (for details, see IARC, 1990)

• (a) Boiling point: 170–17°C at 2.6 kPa
• (b) Conversion factor: mg/m³ = 4.52 × ppm

2. Studies of Cancer in Humans

No data were available to the Working Group.

3. Studies of Cancer in Experimental Animals

Dimethyl hydrogen phosphite was tested for carcinogenicity by oral administration in one strain of mice and in one strain of rats. In rats, it caused an increase in the incidence of alveolar/bronchiolar carcinomas in animals of each sex and of squamous-cell carcinomas of the lung and of papillomas and carcinomas of the forestomach in males (IARC, 1990).

4. Other Data Relevant to an Evaluation of Carcinogenicity and its Mechanisms

4.4. Genetic and related effects

4.4.1. Humans

No data were available to the Working Group.

4.4.2. Experimental data (see Table 1 for references)

Table 1

Genetic and related effects of dimethyl hydrogen phosphite.

In single studies, dimethyl hydrogen phosphite induced sister chromatid exchanges and chromosomal aberrations in Chinese hamster ovary cells in culture and mutations in mouse cells in culture but did not induce sex-linked recessive lethal mutations in Drosophila melanogaster. It was not mutagenic to bacteria in the presence or absence of an exogenous metabolic system.

Dimethyl hydrogen phosphite has been reported to induce unscheduled DNA synthesis in hepatocytes of rats that had been treated with Aroclor or 3-methylcholanthrene.

5. Evaluation

No epidemiological data relevant to the carcinogenicity of dimethyl hydrogen phosphite were available.

There is limited evidence for the carcinogenicity of dimethyl hydrogen phosphite in experimental animals.

6. References

• IARC (1990) IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 48, Some Flame Retardants and Textile Chemicals, and Exposures in the Textile Manufacturing Industry, Lyon, pp. 85–93. [PMC free article: PMC7682352] [PubMed: 2374288]
• McGregor D.B., Brown A., Cattanach P., Edwards I., McBride D., Caspary W.J. Responses of the L5178T tk⁺/tk⁻ mouse lymphoma cell forward mutation assay. II: 18 coded chemicals. Environ. mol. Mutag. 1988;11:91–118. [PubMed: 3338442]
• Shaddock J.G., Robinson B.Y., Casciano D.A. Effect of pretreatment with hepatic mixed-function oxidase inducers on the genotoxicity of four rat carcinogens in the hepatocyte/DNA repair assay. Mutagenesis. 1990;5:387–391. [PubMed: 2169015]
• Tennant R.W., Margolin B.H., Shelby M.D., Zeiger E., Haseman J.K., Spalding J., Caspary W., Resnick M., Stasiewicz S., Anderson B., Minor R. Prediction of chemical carcinogenicity in rodents from in vitro genetic toxicity assays. Science. 1987;236:933–941. [PubMed: 3554512]
• United States National Toxicology Program (1985) Toxicology and Carcinogenesis Studies of Dimethyl Hydrogen Phosphite (CAS No. 868-85-9) in F344/N Rats and B6C3F₁ Mice (Gavage Studies) (Technical Report No. 287; HIN Publ. No. 86-2543), Research Triangle Park, NC, United States Department of Health and Human Services. [PubMed: 12748716]
• Woodruff R.C., Mason J.M., Valencia R., Zimmering S. Chemical mutagenesis testing in Drosophila. V. Results of 53 coded compounds tested for the National Toxicology Program. Environ. Mutag. 1985;7:677–702. [PubMed: 3930237]