According to OSHA, which area must be barricaded to prevent employees from entering?

The correct choice emphasizes the importance of safety in the vicinity of cranes during operation. Barricading the accessible areas within the swing radius of the crane's superstructure is crucial because this is where the risk of injury is highest. The swing radius represents the space around the crane's boom that can be affected by its movement. If employees enter this area when the crane is in operation, they are at significant risk of being struck by the crane or its load, leading to potentially severe injuries or fatalities.

By implementing barricades in this area, employers can effectively minimize access and, consequently, reduce the likelihood of accidents. The barricades serve as a physical reminder to employees of the dangers associated with crane operation and aid in maintaining a safe working environment. Recognizing the critical nature of this safety measure aligns with OSHA's guidelines, which prioritize protecting workers by controlling access to high-risk areas around heavy machinery.