ERRATUM George R. Hoffmann, Genetic effects of dimethylsulfate, diethylsulfate, and related compounds, Mutation Res., 75 (1980) 63--129. Page 75, Paragraph 2. The correct literature citation after the sentence, "Isopropyl methanesulfonate, an agent of low s-value, is reported to be a less efficient mutagen than EMS" is [59,226], not [54,226].