When is it appropriate to remove your lock from the machine controls?

The correct choice emphasizes the importance of safety protocols in machine operation. It is crucial to remove your lock from the machine controls only after ensuring that all safety measures, including replacing machine guards and covers, have been completed. This step is vital because it prevents accidental operation of the machinery while it is still in a potentially hazardous state. By ensuring that all protective devices are in place, one significantly reduces the risk of injury to oneself or others who may be working nearby.

Considering the context of the other choices, removing the lock after completing a routine check, waiting for equipment to cool down, or obtaining permission from a supervisor, while important actions in their own right, do not have the same immediate safety implications as ensuring that guards and covers are appropriately replaced. These other actions can be part of the overall safety procedure, but they should not precede the critical placement of safety features on the machinery. Prioritizing the integrity of machine safety components is essential in any work environment dealing with potentially dangerous equipment.