Key requirements: Underground utilities must be located before excavation begins. Utility companies must be contacted and utility locations marked. Employees exposed to vehicular traffic must wear warning vests. Structural ramps used for employee access shall be designed by a competent person. Employees shall not work in excavations where water has accumulated unless precautions are taken. Employees must be protected from loose rock or soil by scaling, benching, shoring, or other means. Daily inspections by competent person required. Protective systems required for excavations deeper than 5 feet (1.5m). All excavations 20 feet or deeper require design by a registered professional engineer.