Two incineration test programs were conducted at EPA's Incineration Research Facility to evaluate the suitability of incineration as an option to treat contaminated Superfund site soils. The soils from the Purity Oil Sales site in Region 9 are contaminated with lead, up to several percent sulfur, and, to a lesser extent, hazardous organic constituents. The soil from the Baird and McGuire Superfund site in Region 1 is contaminated with pesticides, arsenic, and, to a lesser extent, lead. Incineration could be considered applicable to the treatment of the three Purity Oil Sales site soils tested based on effective semivolatile organic decontamination, in-compliance (with federal standards) particulate emissions, and low SO2/SO3 emissions. However, these tests results suggest that the resulting kiln ash would be a toxicity characteristic hazardous waste due to its leachable lead content. Similarly, for the Baird and McGuire site soils, organic decontamination of the tested materials was effective. Between 36 and 76 percent of the measured arsenic and between 69 and 94 percent of the measured lead were discharged in the kiln bottom ash depending on kiln temperature. The low TCLP leachability of the lead in the kiln bottom ash was not affected by the test variables kiln temperatures and kiln exit flue gas O2. However, the ash arsenic resulting from high excess air operation was significantly less leachable than that from low excess air operation, and was somewhat more leachable at high temperature than at low temperature.