This rulemaking will establish emission limits for hazardous air pollutants (hydrogen flouride (HF), hydrogen chloride (HCl) and metals) emitted from brick and clay ceramics kilns, as well as dryers and glazing operations at clay ceramics production facilities. The brick and structural clay products industry primarily includes facilities that manufacture brick, clay, pipe, roof tile, extruded floor and wall tile, and other extruded dimensional clay products from clay, shale, or a combination of the two. The manufacturing of brick and structural clay products involves mining, raw material processing (crushing, grinding, and screening), mixing, forming, cutting or shaping, drying, and firing. Ceramics are defined as a class of inorganic, nonmetallic solids that are subject to high temperature in manufacture and/or use. The clay ceramics manufacturing source category includes facilities that manufacture traditional ceramics, which include ceramic tile, dinnerware, sanitary ware, pottery, and porcelain. The primary raw material used in the manufacture of these traditional ceramics is clay. The manufacturing of clay ceramics involves raw material processing (crushing, grinding, and screening), mixing, forming, shaping, drying, glazing, and firing.