Cave-In Protection

Cave-ins are the leading cause of fatalities in excavation work, and OSHA requires protective systems for all excavations 5 feet deep or greater unless the excavation is made entirely in stable rock. The three accepted methods of cave-in protection are sloping (cutting the excavation walls back at an angle of repose), shoring (bracing the walls with structural supports), and shielding (using trench boxes to protect workers).

Hydrovac excavations have an inherent safety advantage over traditional trenching because workers typically remain at ground level during the excavation process. The operator directs the water wand and vacuum from above, eliminating the need to enter the excavation during the digging phase. This significantly reduces cave-in exposure compared to conventional excavation methods.

However, when workers must enter a hydrovac excavation for utility repair, inspection, or installation, all OSHA cave-in protection requirements apply. The competent person must evaluate the soil conditions and select an appropriate protective system. Even in situations where workers will only briefly enter the excavation, protection is required if the depth exceeds 5 feet.