Confined spaces pose dangers due to restricted entry and exit, difficult escape, and invisible hazards. Confined spaces are areas not designed for human occupancy like storage tanks, bins, vaults, ventilation shafts, and silos. They may contain lack of oxygen, fires, explosions, toxic gases, and physical hazards such as heat, falls, and machinery. Even empty confined spaces can be risky, so it is important to understand the dangers to work safely in them.