An iron blast furnace casting cage is provided comprising an enclosure for substantially surrounding a blast furnace tap hole and auxiliary equipment and having means defining an upper wall portion disposed above said tap hole and auxiliary equipment and a side wall portion extending generally downwardly from said upper wall portion, an access means in said side wall, an exhaust opening formed in one of said wall portions, said upper and side wall portions adapted to be disposed in a closely surrounding relation to said tap hole, auxiliary equipment and the floor of the cast house, and exhaust means extending from said exhaust opening for withdrawing pollutants generated in said cage.