Which Incident Type requires all Command and General Staff positions to be activated and may exceed 500 personnel?

In the context of the Incident Command System (ICS), the highest complexity and resource demand is characterized by Incident Type 1. This type necessitates that all Command and General Staff positions be activated due to the scale and complexity of the incident. As it often involves extensive coordination, Type 1 incidents can engage more than 500 personnel. These incidents typically require significant management structures, including multiple functional groups dealing with various aspects of the response, such as operations, planning, logistics, finance, and administration.

Understanding this, it's crucial to recognize that lower types, such as Type 2, Type 3, and Type 4, have fewer complexities and may not require the full activation of all Command and General Staff positions. Type 2 incidents might still be large but can often be managed with a less extensive structure, and Types 3 and 4 deal with smaller incidents that usually involve fewer personnel and simpler management requirements. Thus, Type 1 stands out as the type that mandates full activation and is capable of exceeding 500 personnel.