An event where the initial response assignment is 100% committed and additional resources are required is termed:

The term used to describe an event where the initial response assignment is fully engaged and additional resources are required is "working incident." In this context, a working incident indicates that the situation is active and demanding more resources than originally anticipated. This is often recognized in emergency services when responders on the scene assess that the initial units are unable to completely manage the incident, thereby necessitating the call for more support.

A working incident signifies a heightened level of activity and intensity, often leading to a structured command response where additional teams and equipment are required to effectively control the situation. It reflects an acknowledgment that the situation is beyond the capabilities of the current resources, which is crucial for ensuring safety and effective management of the scene. This concept is central to the incident command structure, as it facilitates the organized deployment of necessary assets to address the emergency efficiently.