Final answer:
The Incident Commander should include a Public Information Officer (PIO) once the span of control grows past three to handle communications effectively.
Step-by-step explanation:
Once the span of control grows past three, the Incident Commander (IC) should include a Public Information Officer (PIO). A span of control refers to the number of subordinates or tasks that a supervisor can manage effectively and efficiently. The Incident Command System (ICS) structure often incorporates several specific roles once this limit is exceeded to ensure clear communication and effective management. The PIO is responsible for communicating with the public, media, and other agencies regarding incident operations. This inclusion ensures that information dissemination is handled by a specialized individual, thus preventing misinformation and freeing up the IC to focus on managing the incident.