The paper describes and discusses key design features of the retrofit of EPA's Limestone Injection Multistage Burner (LIMB) system to an operating, wall-fired utility boiler at Ohio Edison's Edgewater Station, based on the preliminary engineering design. The full-scale demonstration is expected to prove the effectiveness and cost of the LIMB concept for use on large-scale utility boilers. To date, a preliminary engineering design for the Edgewater unit has been prepared incorporating the technology developed in smaller-scale studies. EPA is engaged in a multi-year program to develop an improved control technology for emission of sulfur and nitrogen oxides (SOx and NOx) from the combustion of fossil fuels. The technology, called LIMB, involves staged-flow coal burners and injection of a reactive sorbent into the furnace to reduce emissions.