The By-Product Utilization Team at the National Energy Technology Laboratory (NETL) of the US Department of Energy has conducted column leaching tests to characterize the release of various cations from coal utilization by-products (CUB). The release of metals from the nine samples of residues generated in three coal integrated gasification combined cycle (IGCC) installations was determined. Cations tended to be more soluble than from PC fly ash samples. Except for Hg, total cation solubility was due to the relatively high concentration in a few leachate samples. For several IGCC by-product samples generated from a mixture of coal and pet coke, the amount of As, Ni. and Zn extracted from the IGCC residues exceeded primary or secondary drinking water standards in the early leachate samples. Published by Elsevier Ltd.