What should firefighters not do if they see signs of a backdraft during an interior attack?

During an interior attack, if firefighters observe signs of a backdraft, entering the structure can be extremely dangerous and is not advisable. A backdraft occurs when a confined space has accumulated flammable gases, and the introduction of oxygen can lead to an explosive combustion. Signs of a backdraft include smoke being pushed out of the building through cracks or openings, a heavy layer of smoke pooling at the ceiling, and a sudden change in the fire's intensity.

In this context, choosing to enter the structure could expose firefighters to severe hazards, including the potential for an explosive event. Instead, it is vital for firefighters to recognize these signs and implement strategies like initiating ventilation before entry to allow built-up gases to escape and to stabilize the situation to enhance safety.

The other actions mentioned could be appropriate under certain conditions. For example, initiating vertical ventilation can help release heat and gases, reducing the chances of a backdraft upon entry. Using master streams can be effective for addressing the fire from a distance, and checking for gas leaks can help ensure the safety of personnel and prevent further hazards. Therefore, avoiding entry when signs of a backdraft are present is crucial for firefighter safety.