Explains what steps to take to prevent noise-induced hearing loss, which is permanent and irreversible once it has occurred. Sound vibrations are analyzed and their effect on the human hearing system explained. Protection devices are described as to efficiency, cost, ease of wear. Muffs and foam hear plugs are rated best. It is important for the wearer to select a type that will not make him feel confined. The placement of machines, the use of acoustical tiles, padding, are other measures described to reduce noise levels. -- AATA