What is the main requirement for workers at higher levels in sloped excavations?

The main requirement for workers at higher levels in sloped excavations is rooted in the need to ensure safety for those working below. When employees are working on slopes or elevated areas, there is a significant risk of materials or tools falling. Protecting lower-level employees from these potential hazards is paramount in maintaining a safe work environment. This requirement highlights the importance of implementing fall protection measures and ensuring that any items used or moved at higher elevations do not pose a risk to those below.

While other options pertain to safety measures, such as wearing protective gear or having a safety harness, the specific focus of the question is on the obligation to protect workers below from falling objects. Therefore, the correct answer emphasizes the necessity of implementing procedures that safeguard all employees on site, particularly those working at lower levels of a sloped excavation.