The report discusses the control of odorous emissions from iron foundries. The main process sources of odors in iron foundries are mold and core making, casting, and sand shakeout. The odors are usually caused by chemicals, which may be present as binders and other additives to the molding sand, or as breakdown products when these chemicals are subjected to molten iron as it is poured into molds. There are many binder formulations; typical formulations are based on using some form of an oil, urethane, formaldehyde, phenol, or furan. Common additives include coal, cereals, and starches, clays, and refractory minerals such as silica. A great many possible compounds can be formed when these chemicals are exposed to molten iron. Common particulate removal technologies may also reduce odors, although the odors are probably caused by vapor-phase compounds which are not well controlled by cyclones and bag filters. Carbon adsorption may be effective, but might also be very expensive. Wet scrubbers with special additives in the water may be more effective, but may have drawbacks such as generating a waste water treatment requirement and the potential for corrosion. Another technology, reportedly used in Europe, is biofiltration.