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Key value for chemical safety assessment

Additional information

Mutagenic data of methylal are shown in Table below. The only positive mutagenic effect was reported on 2 strains of S. typhimurium by Sam & Kruel (1989) whereas Kitching (1996) stated the negative genotoxicity of methylal. At more, negative results/predictions of Bacterial reverse mutation assay was denoted for methylal with Toxicity Prediction by Komputer Assisted Technology (TOPKAT), Deductive Estimation of Risk from Existing Knowledge (DEREK) for Windows (DfW) and CASETOX, 3 of the most widely used commercial toxicity prediction programs models fort the prediction of Ames test mutagenicity (White et al., 2003). In vitro mammalian chromosome aberration test and Micronucleus assay are both negative.

Test method (genotoxic endpoint measured)

Positive result

Negative result


Bacterial reverse mutation assay (gene mutation)

Positive in S. typhimurium strains TA98, TA100 without activation

Negative in S. typhimuriumstrains TA1535, TA1537, TA1538 with and without activation and strains TA98, TA100 with activation

Sam & Kruel, 1989

Bacterial reverse mutation assay (gene mutation)


Negative in S. typhimuriumTA 1535, TA 1537, TA 98 and TA 100 with and without activation

Negative inE. coliWP2 uvr A with and without activation

Kitching, 1996

In vitro mammalian chromosome aberration test (chromosome aberration)


Negative in Chinese hamster ovary (CHO) with and without activation

Young, 1990

Micronucleus assay (chromosome aberration)


Negative in mouse (in vivo) with and without activation

Ivet, 1990

Short description of key information:

Only one positive result was obtained in bacterial reverse mutation assay with 2 strains of S. typhimuriums without activation. Other results were negative.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

According to CLP Regulation, methylal is not genotoxic and is not classified as mutagenic.

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