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Administrative data

Key value for chemical safety assessment

Additional information

Choice of key study: the most recent reliable study was chosen as key study. The results of the in vitro assays were in agreement, and an in vitro unscheduled DNA study also gave positive results. When tested in vivo, no evidence of clastogenicity was found. The interprepation of the in vitro results is complicated because the purity of the test substance was sometimes questionable. The strains of bacterial cells giving positive results when CHPTAC is tested is the same as that found when EPTAC is assayed. Technical grade CHPTAC contains 2 -3% EPTAC as an impurity, and purified CHPTAC converts to the more reactive epoxy (EPTAC) depending on pH: at the typical test pH of 7.5 approximately 50% conversion of the CHPTAC could occur.

Short description of key information:

In vitro:

Gene mutation (Bacterial reverse mutation assay / Ames test): positive with and without activation (OECD TG 471)

Cytogenicity in mammalian cells: positive with and without activation in human lymphocytes (EEC 79/831, B10)

Gene mutation (Mammalian forward mutation CHO/HGPRT assay assay): positive with and without activation in CHO cells (similar to OECD TG 476)

In vivo: negative in mouse micronucleus assay (OECD TG 474)

Justification for classification or non-classification

The in vitro evidence for mutagenicity is not supported by the in vivo result available. It is though that the positive results in vitro may result from the conversion from CHPTAC to EPTAC. It is therefore considered that non-classification is justified.