The report gives results of a full-scale utility demonstration of Combustion Engineering's Low-NOx Concentric Firing System (LNCFS), conducted at Utah Power and Light's 400 MWe Hunter No. 2 boiler. This program was implemented to investigate and evaluate the effectiveness of using concentric (offset) firing to reduce NOx emission levels from tangentially coal-fired utility boilers. The tests covered the period from August 1981 to March 1984 and included six short-term boiler characterization test series and four long-term (30-day) continuous emissions monitor (CEM) tests. A total of 384 characterization tests were conducted during the six test series, analyzing boiler performance and emissions as functions of excess air, load, fuel elevations in service, burner tilt, overfire air (OFA) flow, OFA tilt, offset angle, and fuel-air flow. Additionally, furnace wall corrosion was monitored, both short- (with corrosion coupons) and long-term (with wall thickness measurements), by another contractor. Overall program results have shown NOx emissions levels of about 0.4 lb NOx per million Btu for the 30-day continuous monitoring periods and about 0.3 lb NOx per million Btu for the short-term optimization tests. These levels represent 33 and 50% reductions in NOx emissions levels, respectively, from baseline standard operating procedures.