In this study, a novel chemical fixation agent, colloidal aluminate oxide (CAO), has been synthesized and characterized in detail. CAO does not require cementitious additives, and can be used as a stabilizer of lead in the fly ash from municipal solid waste incineration (MSWI) plants. CAO reveals a high reduction ratio for the leachability of Pb of 94.8% when compared with three commercial fixation agents, MF-103, BTS-03 and POCAT and two fine chemicals, ethylene diaminetetracetic acid (EDTA) and thiodiglycolic acid (TGA). A possible mechanism for CAO stabilization of lead is formulated based on the results of Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) spectra. (C) 2004 Elsevier B.V. All rights reserved.