This report describes the results of a survey of operational flue gas desulfurization (FGD) systems on coal-fired utility boilers in the United States. The FGD systems installed on Units 4 and 5 at the Lawrence Energy Center of the Kansas Power and Light Company is described in terms of design and performance. The FGD system installed on each unit consists of two parallel two-stage scrubber modules, each of which includes a rectangular, variable-throat rod-deck venturi scrubber arranged in series with a spray tower absorber. Each system is also equipped with slurry-hold tanks, mist eliminators, and in-line reheaters, as well as isolation and bypass dampers. The two systems share a common limestone storage and preparation facility and waste-disposal facility. These FGD systems represent a second generation design replacement of limestone furnace-injection and tail-end scrubbing systems which were originally installed on Units 4 and 5 in 1968 and 1971, respectively. The original systems operated approximately 27,000 hours and 23,000 hours on coal-fired flue gas for Units 4 and 5, respectively. The redesigned FGD system on Unit 4 went into service in early January 1977. The Unit 5 FGD system went into service on April 14, 1978.