Final answer:
OSHA standards generally apply to all excavations, regardless of depth, to prevent worker hazards. However, excavations less than 5 feet deep may not require the same safety systems unless a cave-in risk or other hazard exists
Step-by-step explanation:
The question asks which instance the OSHA soil's standard does not apply to, among four given options. According to OSHA standards designed to protect workers from various hazards, these standards apply regardless of the excavation depth and include safety measures for preventing trenching cave-ins and dealing with unstable or water-saturated soils. Hence, all the provided options usually fall under OSHA's purview for worker safety. However, in some instances, excavations less than 5 feet deep may not necessarily require the same extensive protective systems as deeper excavations, unless there is a potential for a cave-in or other recognized hazard present.