Seven chemicals commonly found at industrial waste sites were tested with the Tradescantia-micronucleus (Trad-MCN) assay to evaluate their clastogenic potential. They were: Aldrin, arsenic trioxide, 1,2-benz(a,h)anthracene, dieldrin, heptachlor, lead tetraacetate, and tetrachloroethylene. Results of repeated tests for clastogenicity yielded the minimum effective dose (MED) of 0.44 ppm for lead tetraacetate, 3.81 ppm for dieldrin, and 1.88 ppm for heptachlor. Arsenic trioxide and 1,2-benz(a,h)anthracene yielded positive responses at the MED of 3.96 ppm and 2.28 ppm, respectively. Aldrin and tetrachloroethylene were considered to be immiscible with water, and the test yielded negative responses. Results of tetrachloroethylene fume treatment yielded a positive response at the MED of 30 ppm/min in 2-hr exposures. Five chemicals determined to be clastogens by the test were ranked according to their MED in the descending order of potency as follows: Lead tetraacetate, heptachlor, 1,2-benz(a,h)anthracene, dieldrin, and arsenic trioxide. Results of the study indicate that Trad-MCN bioassay could be effectively utilized for assessing the genetic hazard from the leachates and volatile compounds emanating from uncontrolled industrial waste sites. (Copyright (c) 1989 Elsevier Science Publishers B.V. (Biomedical Division.)