In this study, we used the multiple toxicity characteristic leaching procedure to test the long-term leaching behavior of bottom ash, scrubber residue, and baghouse ash from a municipal solid waste incinerator (MSWI). We used the short-term viability percentage of African green monkey kidney cells (Vero cells) as a bioindicator to investigate the cytotoxicity of the leachates from the MSWI ash wastes. We found that strontium was a significant contributor to the cytotoxicity of the bottom ash. (C) 2009 Elsevier B.V. All rights reserved.