New coal reaction technology called ReEngineered Feedstock (ReEF), consisting of post-recycled paper and plastics, was evaluated for combustion emissions control when cofiring with pulverized coal. Experiments were conducted with four types of ReEF in a 2 in. diameter laboratory-scale fluidized bed combustor system heated to 1200, 1400, and 1600 °C. Flue gas emission was continuously monitored with an online infrared multigas analyzer and mass spectrometer. The results indicate that co-firing ReEF with coal provides SO2 emission reduction in flue gas up to 85% and moderate decrease in NO emissions, as well as higher carbon conversion than pure coal combustion. ReEF, slag and fly ash solids were were analyzed by X-ray diffraction; identification of sulfates in the product ash conclusively supports the mechanism of in situ sulfur capture.