Number of chromosomal aberrations (excluding gaps) per 100 lymphocytes scored associated with occupational exposure to cancer chemotherapy agents. Two studies reporting no difference between exposed and unexposed subjects do not appear on the figure because the authors did not report the data values in the publication (Krepinsky et al., 1990) or the reported data were log-transformed and thus could not be included on the same graph with remainder of the data (Cooke et al., 1991).