Poor lighting in parking lots, hallways, and other areas can cause a number of accidents. Dark areas can also pose a security threat and raise the risk of crime. Potholes and oil spills in parking lots can cause slip and fall accidents. Swimming pool accidents are also quite common at resorts when the property managers fail to post rules and warnings; schedule an adequate number of lifeguards; clean up spills; or remove glass and other debris that can cause injury. Slips and falls can occur almost anywhere if the property manager is negligent and does not warn patrons or clean up the spill. Visitors can also suffer injury due to negligent hiring practices, when inexperienced or poorly trained staff causes them personal injury.