The problems of local exhaust ventilation and air recirculation in foundries are discussed. Most foundries are small with fewer than 100 employees, for which the investment and monitoring costs of pollution control will be high. The design of foundries and their use of a large number of materials, and hence decomposition products, makes individual attention essential. The major hazard is silica dust, but the organic compounds in binders have unknown effects. Air recirculation should be treated as a materials handling problem, since, due to ventilation, foundries handle more air than castings and sand.
Recirculation of Exhaust Air, Division of Physical Sciences and Engineering, NIOSH, HEW Publication No. (NIOSH) 76-186