For definition of Groups, see Preamble Evaluation.
VOL.: 60 (1994) (p. 445)
Chem. Abstr. Name: 2-Methyl-2-propenoic acid, methyl ester
Methyl methacrylate is produced mainly by a process based on the reaction of acetone with hydrogen cyanide. It is an important monomer used mainly in the production of acrylic sheeting, moulding powders and resins and surface coatings. Occupational exposures have been measured during its production and during its use in polymers, as a component of surgical bone cement, in denture fabrication and during the preparation of artificial fingernails.
A large mortality study was conducted of workers in acrylic sheet manufacture in two US plants. A significant increase in mortality from colon cancers was seen in one plant and a nonsignificant increase in the other; a nonsignificant increase in mortality from rectal cancer was found in the first plant. The increases were most evident among workers employed during the earliest production period and in jobs entailing the highest exposure. Exposure was predominantly to methyl methacrylate, but workers were also exposed to ethyl acrylate and to volatile by-products of the polymerization process.
Another US study examined the mortality of workers employed in methyl methacrylate manufacture and polymerization and found no significant increase in the number of cancer deaths.
Methyl methacrylate was tested for carcinogenicity in one experiment in mice and one experiment in rats exposed by inhalation. No significant treatment-related increase in tumour incidence occurred. One study in rats by oral administration was inadequate for evaluation.
Methyl methacrylate can be absorbed through the skin and is rapidly metabolized in man. In rats, it is first hydrolysed, and the dominant metabolic pathway is to fully oxidized carbons which are exhaled as carbon dioxide; a very small proportion is excreted as thioethers in the urine. Methyl methacrylate produces a number of toxic effects in man and experimental animals.
Exposure of mice and rats to methyl methacrylate by inhalation had no adverse reproductive effects.
No data were available on the genetic and related effects of methyl methacrylate in humans.
It caused chromosomal aberrations in rat bone marrow but did not induce micronuclei in mouse bone marrow in vivo. Gene mutation, sister chromatid exchange, micronuclei and chromosomal aberrations were induced in mammalian cells in vitro. Methyl methacrylate did not cause reverse gene mutation in bacteria but induced forward gene mutation in Salmonella typhimurium in a single study in the presence of an exogenous metabolic activation system.
There is inadequate evidence in humans for the carcinogenicity of methyl methacrylate.
There is evidence suggesting lack of carcinogenicity of methyl methacrylate in experimental animals.
Methyl methacrylate is not classifiable as to its carcinogenicity to humans (Group 3).
For definition of the italicized terms, see Preamble Evaluation.
Previous evaluation: Suppl. 7 (1987) (p. 66)
See Also: Toxicological Abbreviations Methyl methacrylate (ICSC) Methyl methacrylate (CICADS 4, 1998)