What phrase indicates an imminent fire ground hazard?

The phrase that indicates an imminent fire ground hazard is "Emergency Traffic." This term is used in the context of fire incidents to alert all personnel that there is a critical situation that requires immediate attention or action. "Emergency Traffic" is typically called over the radio when a situation is so severe that it may endanger lives or compromise the safety of the operation. It instructs all responders to cease other communications and focus on the emerging hazard, ensuring that everyone is aware of the urgency and can respond appropriately.

While the other phrases are also used in emergency services, they do not convey the same immediate urgency as "Emergency Traffic." For instance, "Firefighter Down" refers specifically to a situation where a firefighter has become incapacitated, prompting life-saving interventions. "Code Red" is often associated with building fires within certain organizations, indicating a fire emergency but does not necessarily imply imminent danger for all personnel. "Possible Explosion" suggests a risk but does not communicate the immediate urgency that "Emergency Traffic" does when on-scene.