Subpart P: Excavations. 1926.651: General requirements — underground utility locations before digging (811 call). Access (ladder/ramp) within 25 ft of travel in trenches ≥4 ft deep. Daily inspections by competent person. 1926.652: Protective systems required for excavations ≥5 ft (unless competent person determines soil is stable rock). Four options: Sloping — cut sides back to stable angle. Type A soil: 3/4:1. Type B: 1:1. Type C: 1.5:1. Benching — Type A and B only, Type C not permitted. Shoring — hydraulic, pneumatic, or timber. Tabulated data in Appendix C/D. Trench shields/boxes — min rated for soil depth. Soil classification: Type A (unconfined compressive >1.5 tsf — clay, cemented sand), Type B (0.5-1.5 tsf — angular gravel, silt, previously disturbed soils), Type C (<0.5 tsf — gravel, sand, submerged soil, fissured material). Testing: thumb penetration, pocket penetrometer, vane shear. Surface water diversion. Spoils ≥2 ft from edge. No workers under loads being lifted by excavating equipment.