The U.S. Bureau of Mines has investigated the treatment of arsenic- containing copper industrial bleed streams by sulfuric acid leaching of metal values and subsequent metal recovery stages. The primary objectives were to recover valuable metals, particularly copper, and to remove arsenic into a nonhazardous, storable or salable product. Acid leaching of an arsenic-containing flue dust solubilized arsenic, cadmium, molybdenum, zinc, copper, iron, and bismuth in decreasing order. Insoluble lead remained in the leach residue. Bleed electrolyte from a copper refinery was determined to be a viable source of sulfuric acid for leaching, and coprocessing the flue dust with bleed electrolyte provides an option for treating both bleed streams with a single process. Several metal-recovery options were considered, including (1) copper removal as copper sulfate with so2 reduction and precipitation of arsenic, (2) removal of arsenic by selective precipitation with calcium and iron with subsequent copper cementation and stabilization of arsenic in a sulfide or vitrified form, and (3) solvent extraction of arsenic and molybdenum followed by copper cementation.