Never enter a trench unless you are trained to recognize the hazards and it has been inspected by a competent person. Trench collapses, or cave-ins, can be prevented by taking the following steps:SLOPE or bench trench walls at an angle inclined away from the excavation. SHORE trench walls by installing aluminum hydraulic or other types of supports to prevent soil movement. SHIELD trench walls with trench boxes or other types of supports to prevent soil cave-ins. Employers may contact their local OSHA area office for assistance or take advantage of OSHA’s free and confidential On-Site Consultation Program.