The main sectors are flat glass, container, pressed ware, art glass, and special glass (optical and electronic). The main processes are melting, fining, mixing, annealing, and forming. Art glass production still involves manual batch handling and glass blowing. Flat glass and container glass production has become increasingly automated. Potential exposures in glass production include silica, asbestos, metals, and PAHs. Workers are exposed to lead (crystal), arsenic, and antimony in art glass manufacturing. There is limited evidence of increased cancer risk in studies of workers who manufactured art glass, glass containers and pressed ware. There is inadequate evidence of increased cancer risk for workers manufacturing flat glass and special glass. [IARC: Exposures in the Glass Manufacturing Industry] Arsenic and antimony are fining agents used to eliminate bubbles during melting. Hydrofluoric acid is used in etching and sulfuric acid in polishing glass. [Kanerva, p. 956-7] Studies of batch mixers and oven chargers in the art glass industry found arsenic levels always higher than the current TLV-TWA. Arsenic trioxide and antimony trioxide are used as fining agents. [Multiple Exposure to Arsenic, Antimony, and Other Elements in Art Glass Manufacturing. PMID 9617389] See the Activity, "Glassblowing."