The paper describes the use of an EPA LIMB cost model, in conjunction with cost and performance models for flue gas desulfurization (FGD), to compare these two technologies under similar premises. (NOTE: The performance goals of LIMB, EPA's acronym for Limestone Injection/Multistage Burners for use in SO2/NOx control for coal-fired boilers, are 50-60% reduction of SO2 and NOx for retrofit systems, and achievement of New Source Performance Standards (NSPS) for SO2 and NOx for application on new utility boilers. These performance requirements, furthermore, are to be achieved at significantly lower cost than that for FGD, the major control technology alternative.) For a new 500 MW unit burning 1.92% S coal and achieving control to meet NSPS, costs per ton of SO2 removed are estimated to be $1377, $771, and $921 for limestone FGD, lime spray drying, and LIMB using calcitic hydrate, respectively. At 0.48% S in the coal, these costs are estimated at $3715, $1954, and $1134 for limestone FGD, lime spray drying, and LIMB, respectively. For a 300 MW retrofit system, costs per ton of SO2 removed for wet limestone FGD and LIMB using calcitic hydrate on a 1.92% S coal application are $1359 and $844, respectively.