Fig. 1

Relative survival and mutant frequency in TK6 assay for the 10 chemicals conducted by each laboratory. According to the OECD guidelines (TG490), dose finding tests were conducted before the main TK6 assays. The short- and long-term treatments were conducted for 4 h (+/−S9mix) and 24 h (−S9mix), respectively. The main tests were conducted so that the highest concentration was set at a concentration where the RS was from 10 to 20%. Experiments and statistical analysis were conducted as described in Materials and Methods. (a) indicates the data of MF were excluded from the statistical judgment because RS was below 10%