When should a trench be shored or supported?

The correct choice indicates that a trench should be shored or supported whenever there is a risk of collapse. This requirement is crucial for the safety of workers who may be in or near the trench. Trench collapses can occur for various reasons, including the soil type, moisture content, and the length of time the trench has been open. Therefore, assessing the risk factors associated with each specific trench scenario is vital for ensuring safety.

This approach goes beyond just the depth of the trench or the presence of workers, addressing the inherent dangers that exist under various conditions. Relying solely on criteria like the depth exceeding 5 feet or considering only wet conditions does not encompass all potential hazards. Similarly, the presence of workers is not the only factor that necessitates shoring; the nature of the soil and environmental conditions must be monitored continuously to protect those who may be at risk. Thus, ensuring that a trench is shored or supported based on the overall risk of collapse is the most comprehensive and safety-conscious approach.