Which of the following is an example of a fixed hazard?

The correct answer, conveyor belts in a factory, exemplifies a fixed hazard because it is a stationary piece of equipment that is permanently installed in an operational area. Fixed hazards are typically part of the infrastructure and remain in place during operations, representing a constant potential risk to workers if proper safety measures and precautions are not taken.

In contrast, vehicles used for operations are mobile and can change location, thus not fitting the definition of a fixed hazard. Mobile scaffolding is designed for flexibility and can be moved or relocated, which also excludes it from being classified as fixed. Similarly, portable generators are designed to be moved as needed for various tasks and do not remain in a single location, reinforcing the distinction from fixed hazards. Therefore, while all the other options involve equipment that can pose hazards, only the conveyor belt's stationary nature classifies it as a fixed hazard.