Which of the following is NOT a hazard category at the operational level?

The correct choice reflects that "Latent" is not recognized as a hazard category at the operational level. In the context of operational hazard categories, expected hazards pertain to those anticipated based on routine operations, imminent hazards are those that present a clear and immediate danger requiring quick action, and environmental hazards refer to risks that arise from the surrounding environment impacting safety and operational effectiveness.

Latent hazards, however, refer to situations where the potential for harm exists but may not be immediately observable or active. They often require a deeper analysis to recognize, as they can be ingrained in processes or systems but do not pose an immediate threat. In safety operations, understanding the difference between latent hazards and more immediate threats is crucial for effective risk management and prioritizing safety measures. Thus, "Latent" does not fit within the primary categories when assessing immediate operational hazards.