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Key value for chemical safety assessment

Additional information

In vitro:

An OECD guideline study (471) showed a weakly mutagenic effect in bacteria when tested in concentrations ranging from 20 - 7500 ug/plate with and without S-9 mix. Several Salmonalle typhimurium strains were used (BASF, 1989).

DOW (1980) reported an Ames test equivalent or similar to OECD guideline 471. A positive effect with and without metabolic activation was found for the bacterial strains TA100 and TA 1535. Concentrations used in this report were 39, 75, 149, 298, 599 or 1198 ppm.

In a bacterial gene mutation assay using S. typhimurium strains TA1535, TA1537 and TA1538 positive results were found using TA 1535 (plate test and suspension test). A negative result was shown for TA 1537 and TA1538 in the plate test and suspension test. Concentrations ranged from 0.05 - 0.2%. This test was done with and without metabolic activation.

Anderson et al. (1990) reported a positive result without S-9 mix at the highest dose (500 ug/ml), and an equivocal result with S-9 mix in an chromosomal aberration test with Chinese hamster ovary cells. Concentrations tested were 16 - 500 ug/ml.

In a mammalian gene mutation assay with mouse lymphoma L5178Y cells, McGregor et al. (1987) found a positive result with and without S-9 mix. Concentrations tested were 50 - 800 ug/ml.

With Saccharomyces cerevisiae the test substance was not active in producing frameshift mutations or mitotic gene conversions. Concentrations used were 0.25, 0.5 and 1%; this test was done with and without metabolic activation.

In vivo:

Negative results were seen in an chromosome aberration assay (OECD guideline 475). The test substance was given via inhalation (7 single exposures for 5 consecutive days) to male and female rats (NIOSH, 1981). Concentrations used were 250 and 1000 ppm.

In a dominant-lethal test (NIOSH, 1981) according to OECD guideline 478, butylene oxide had no identifiable effect on male rats when given in doses of 250 and 1000 ppm to male rats via inhalation (vapour).

Endpoint Conclusion:

Justification for classification or non-classification

The mutagenic effects found in vitro could not be confirmed in in vivo studies and the test compound appears to exert genetic effects only on the local and not the systemic level. Gonadic tissues do no seem to be affected. Hence, classification is not warranted.