Which of the following is a guideline when working on, around, or under apparatus?

Having a second person present while working on, around, or under apparatus is a critical safety guideline that enhances overall safety and ensures support in case of an emergency. This practice is rooted in the concept of buddy systems, which help to monitor each other's safety and provide immediate assistance if an accident occurs. The presence of a second person can also facilitate better communication and decision-making during the tasks at hand, offering support and reducing the risk of accidents.

In the context of this guideline, having a second person can be especially important when working in potentially hazardous conditions where movement around heavy equipment or under vehicles is involved. With a partner present, there is an added layer of safety, as one person can focus on the task while the other remains vigilant to any unforeseen dangers.

Other choices may include practices that provide added safety but do not encompass the comprehensive support system that having a second person offers. For instance, having maintenance personnel or notifying someone about your location may enhance communication but do not provide the immediate assistance that a second person can offer. Carrying a hand-held radio is useful for communication, yet it cannot replace the vital presence and support of another individual actively engaged in the work environment.