From October 18 to November 2, 1973, the Environmental Protection Agency held a national public hearing in the Washington, D.C. area to review the status of power plant compliance with sulfur oxide (SOx) air pollution emission limitations. Regulations limiting emissions of SOx have been imposed because excess quantities of SOx seriously affect human health through increased incidences of respiratory disease and damage many types of materials. The national hearing was called because power plants are the largest source of SOx emissions in the U.S., because large numbers of power plants were not yet in compliance with SOx emission limitations, and because, in most cases, only 1 1/2 years remained under the established implementation plans for these plants to achieve compliance. It was generally agreed at the hearing that FGD systems, when operating properly, would reduce SOx emissions by 85 to 90%, the levels required by most states. Questions were, however, raised by many utilities as to whether FGD systems could be made to operate reliably and as to whether an environmentally acceptable method existed to dispose of the sludge produced by some types of FGD systems. The panel additionally found that technology was available to reclaim sludge waste as landfill and that regenerable systems that do not produce any appreciable waste were available for use where throwaway systems could not be used.