In 1976, the Industrial Environmental Research Laboratory at Cincinnati sponsored a research program at the Mineral Research Center, Montana Tech Alumni Foundation, to investigate a variety of approaches to the fixation of arsenic bearing wastes, particularly smelter flue dusts, to render them harmless to the environment. The enclosed document reports the findings of this work. A comprehensive program was undertaken to investigate various methods of fixing arsenic bearing flue dust wastes produced in smelting of nonferrous metal concentrates. The program was comprised of three principal elements: (1) separation of the arsenic from metal values by leaching; (2) incorporation of the arsenic into a fixation matrix; and (3) leach testing of samples of the fixed product to determine suitability for environmental protection. Stabilization of the arsenic by incorporation in slag matrices and in cements, mortars, clays, and concrete was investigated. The most promising technique found was stabilization by dissolution in the slag matrix to form a solid solution upon cooling.