Residuals are a problem of gargantuan size as well as complexity. The Office of Solid Water Waste Management Programs has presented testimony to the U.S. House of Representatives concerning the quantity and composition of the non-hazardous and hazardous discarded materials stream. This includes 1,783 billion tons of mining waste, 687 million tons of agricultural wastes, 135 million tons of municipal wastes, 260 million tons of industrial wastes, and 7.3 million tons of sewage sludges. This imposing number of three to four billion tons of solid waste must be disposed of predominantly on land. EPA has further documented over 23 million tons of potentially hazardous waste produced by eight groups of industries. The growth of sludges as a result of air and water pollution controls standards may take dramatic jumps if the 1977 and 1983 mandates of Public Law 92-500 are met. We also expect an increase in potentially hazardous waste by 1983 of 31 million tons by dry weight, an increase of over 33 percent in nine years; and, the growth of all solid wastes are increasing between 2.5 and 4.5 percent per year. We must examine the technical issues on residuals management and to help narrow the gap between what we know and what we need to know.