At an incident involving flammable liquids or gases, firefighters should immediately retreat to a safe location:

• A. When the wind shifts suddenly.
• B. If the sound of escaping gas starts to get louder.
• C. After the fire reaches ignition source.
• D. Only after all other teams have evacuated.

Answer: (B)

At incidents with flammable liquids or gases, the priority is to avoid exposure to evolving vapor and the risk of a rapid ignition. The sound of escaping gas getting louder is a clear, time-sensitive warning that a larger amount of gas is being released and vapors may be accumulating in the area. That combination greatly raises the chance of a flash fire or explosion if an ignition source is present, so retreating to a safe location immediately minimizes exposure and danger.

Wind shifts and other signs matter, but they do not by themselves indicate an immediate, escalating release the way a growing audible gas leak does. Waiting for ignition, or for others to evacuate first, is risky—each responder should move to safety promptly when a worsening gas release is detected.