According to the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA), a confined space is large enough for a person to fit in and perform tasks, and is limited in the ways a person can enter or exit. A confined space is not designed for a person to occupy for an extended amount of time. Confined spaces include manholes, storage bins, tanks, vessels, vaults, tunnels, ductwork, pipelines, silos, and pits.