Data analysis. The data in the text, figures and tables are mean
±SD. Each N for the rat data represents an individual animal. Each N
for the human data represents an individual donor. However, for the
24-h study, two skin samples from each donor were used for each
dose and 4 skin samples from each donor were used for the 48-
h exposure and the tape-stripping experiments. The data for these
latter experiments were averaged for each individual.