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Toxicological information

Carcinogenicity

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Description of key information

inhalation
rat, 2 years: negative (NTP, 1986)
mouse, 2 years: negative (NTP, 1986)
oral
rat, 2 years: negative (Borzelleca et al. 1964)

Key value for chemical safety assessment

Additional information

inhalation

Groups of 50 male F344/N rats were exposed to methyl methacrylate (purity >99%; containing 0.04 mg/1 equivalent to 10 ppm monomethylethyl ether of hydroquinone as an inhibitor of polymerization) by inhalation at ca. 0, 2.05 and 4.1 mg/L (equivalent to 500 or 1000 ppm), female F344/N rats at ca. 0, 1.03 or 2.05 mg/L (equivalent to 250 or 500 ppm) and male and female B6C3F1 mice at ca. 2.05 or 4.1 mg/L (equivalent to 500 or 1000 ppm), 6 hours a day, 5 days a week for 102 weeks (NTP, 1986).

No significant differences of the survival rates were observed between any groups of rats and mice. Reductions in mean body weights of high dosed animals were considered as secondary effects based on the observed inflammations and degenerations of the olfactory epithelium in all MMA treatments. The marginal increase in the incidence of mononuclear-cell leukaemia observed in female rats (control 11/50; low-dose 13/50; high-dose 20/50) fell within the range of values seen in historical controls. Both in mice and rats no treatment-related tumours were observed.

No treatment-related increases in tumour incidence occurred in Golden hamsters with groups of 53-56 males and 56-59 females exposed to ca. 0, 0.103, 0.41 and 1.64 mg/L (0, 25, 100 or 400 ppm) MMA 6 h/d, 5 d/wk for 78 weeks (no interim sacrifice). At the high-dose, body weight decreased and mortality increased in high dose males (Rohm and Haas, 1979). There were no clinical signs or haematological effects attributable to exposure to methyl methacrylate at either the 52- or 78-week sampling times. No gross haematological changes indicative for a possible exposure-related effect were observed.

oral

An early 2-year chronic study on rats treated orally with MMA revealed no adverse effect other than slightly elevated kidney weights in high-dose female rats (Borzelleca et al., 1964) . A similar 2 -year study in dogs suffers from a low number of animals per dose and short study duration, but revealed also no adverse effect other than a lower body weight gain in high-dose animals (Borzelleca et al., 1964).

Justification for classification or non-classification

No carcinogenic potential was detected in reliable inhalation studies in rats, mice, dogs and hamsters. Therefore, methyl methacrylate has not to be classifed as carcinogen according to 67/548/EEC and UN-GHS requirements, respectively.