The training exercise shall be stopped immediately when the __________ determines a potential hazard.

The training exercise must be halted when the instructor in charge identifies a potential hazard because this person has the overall responsibility for the safety and conduct of the training. The instructor in charge is typically the individual with the most direct authority to make immediate safety decisions during training scenarios. Their training and experience empower them to recognize situations that could compromise safety, ensuring that all participants remain safe and that the training environment is managed appropriately.

In this context, while other roles such as the safety officer or AHJ (Authority Having Jurisdiction) representative also play critical roles in maintaining safety, the instructor in charge has the ultimate authority to pause or stop activities. This authority is essential in preventing accidents or injuries, reflecting a key principle in safety management during live fire training exercises.