“…It was also negative in one assay on TA102 with or without metabolic activation (up to 5,000 lg/plate) (McGregor et al, 2005) but was positive in another assay in TA102 in the presence of an exogenous metabolic system at (750 lg/plate) and equivoval in the absence of metabolic activation (Williams-Hill et al, 1999) TBA. It was also negative in a gene mutation assay in mouse lymphoma L5178Y cells at the tk locus up to 5,000 lg/mL (McGregor et al, 1988;NTP, 1997), a chromosomal aberration test in CHO cells up to 5,000 lg/mL (Galloway et al, 1987;NTP, 1997) and a sister chromatid exchange (SCE) test in CHO cells up to 5,000 lg/mL (Galloway et al, 1987;NTP, 1995) in the presence or absence of metabolic activation. A positive result was noted in a Comet assay in human HL-60 leukaemia cells in the absence of metabolic activation at a concentration of 1 mM (Tang et al, 1997).…”