Liquid industrial wastes of the rolling operations are roll-cooling water, descaling water, and waste pickle liquor. The principal pollutional features of these wastes are suspended solids, oil, grease, acid, and soluble iron. The suspended solids are fine particles of iron oxide (mill scale) which are removed from the surface of the product in the process. A description is presented of the processes with emphasis on operations producing liquid wastes is presented. Information on the volume and character of the wastes is given. Measures which remedy or abate the liquid waste problems of the industry are discussed.