What is the primary role of the second arriving Engine Company?

The primary role of the second arriving Engine Company is to secure the water supply and lay supply lines. This is crucial because the first Engine Company may have already engaged the fire, and the second company ensures that an adequate water source is available for sustained firefighting operations. By laying supply lines, they facilitate efficient water delivery to the fire scene, which is vital for effective suppression efforts.

In addition to establishing water supply, the second Engine Company can also take on tasks such as supporting other firefighting operations, but their immediate responsibility is focused on ensuring that water is readily accessible. This foundational work allows the first arriving units to concentrate on firefighting activities without interruption.

The other roles listed, while important, generally fall to different incoming units or may occur at subsequent stages of the incident management. For instance, conducting a size-up is typically the responsibility of the first engine or officer on the scene to assess conditions and develop a strategy. Similarly, rescue operations are often prioritized by the first or additional units as situations dictate, and assuming command might only be necessary if the initial Incident Commander becomes incapacitated or needs support.