Inorganic ash chemistry and petrology was investigated in coal-combustion by-products from the burning of tire-derived fuel (TDF) with a 1: 1 blend of Colorado and Utah high volatile C bituminous coal and Powder River Basin subbimminous coal. Both coal components had high vitrinite contents. With the exception of Sr and Ba, the trace-element contents of the coals were not high. The fly ash was enriched in Zn, known to be a constituent of both the rubber and the wire in tires. Cu, also a constituent of the brass coatings of bead wire, was enriched in the same fractions with high Zn concentrations. Zn and Cu, along with several other elements, increased in concentration in the back, cooler row of the electrostatic precipitator. The enrichment of other elements, such as Se, As, and Pb, was more problematical. It is possible that the latter elements have more of a coal source than a tire source. (C) 2003 Elsevier B.V. All rights reserved.