People employed in libraries do a wide range of automated and manual jobs. In large libraries these jobs may be assigned to one person or a group of persons. In smaller libraries the same person may do several different tasks. Library work has a number of health and safety hazards. These hazards include psychological stress, risk of slips, trips and falls, back injury, personal safety concerns, inadequate workstations, inadequate lighting, dusts, molds and poor indoor air quality.