The paper gives results of an evaluation of a 0.6 MW precombustion chamber burner, designed for in-furnace NOx control, high combustion efficiency, and retrofit applications, for use with high nitrogen content fuel/waste mixtures. The 250- to 750-ms residence time precombustion chamber burner mounted on a prototype watertube package boiler simulator used air staging and in-furnace natural gas reburning to control NOx emissions. The paper reports results of research in which the low NOx precombustor was used to examine the co-firing characteristics of a nitrogenated pesticide, containing dinoseb (2-sec-butyl-4,6 dinitrophenol) in a fuel-oil/xylene solvent. The dinoseb formulation as fired contained 6.4% nitrogen. NO emissions without in-furnace NOx control exceeded 4400 ppm (at 0% O2). When NOx controls in the form of air staging and natural gas reburning were used, these emissions were reduced to < 150 ppm (96% reduction). Average CO and total hydrocarbon emissions were typically < 15 and 2 ppm, respectively. No dinoseb was detected in any emission sample, and the destruction efficiency was determined to be > 99.99%. Mutagenicity studies of the dinoseb emissions showed that reburning (used for NOx control) reduced the mutagenic emission factor about 60-70% from that with air staging alone.