A comprehensive test program was developed to determine the ratios of hexavalent to total chromium and nickel subsulfide to total nickel for a typical municipal wastewater sludge incinerator under normal combustion conditions and improved combustion conditions. Emissions of metals, hexavalent chromium, nickel subsulfide, polychlorinated dibenzodioxins and furans (PCDD/PCDFs), semi-volatile and volatile organic compounds, carbon monoxide (CO), and total hydrocarbons (THCs) from two multiple hearth incinerators and a fluidized bed incinerator were measured. The emissions were controlled at each unit with venturi scrubbers and, on two of the units, emissions from wet electrostatic precipitators (ESPs) were determined. Flue gas sampling was conducted at the inlet and outlet of the air pollution control devices at three separate sites. Gas concentrations, mass emission rates, metals-to-particulate ratios, and emissions factors were reported. Analytical results for the process samples were reported.