Which action is critical during the overhaul stage of firefighting?

During the overhaul stage of firefighting, determining the origin of the fire is critical because it helps to understand what caused the fire and how it spread. This information is vital for several reasons: it allows investigators to gather evidence that can help prevent future incidents, indicates potential safety hazards present in the environment, and ensures that all fire sources have been completely extinguished to mitigate the risk of rekindling.

Identifying the fire's origin facilitates a comprehensive investigation, which is necessary for effective fire prevention strategies. Beyond just extinguishing the flames, this phase ensures that all areas have been thoroughly checked and analyzed. Understanding the cause can also provide insights into building vulnerabilities or compliance issues that might need addressing in future operations.

The other options do not address the critical aspects necessary for ensuring thorough fire investigation and prevention.