To effectively overhaul a class B fire, which step should be taken first?

To effectively overhaul a Class B fire, the first step should involve securing the source and covering it with Aqueous Film-Forming Foam (AFFF). This is because Class B fires involve flammable liquids, and simply removing the fuel source may not be feasible or safe if the fire is actively burning. AFFF works by creating a barrier between the fuel and the air, suppressing the fire and preventing reignition.

By applying AFFF, you are directly addressing the burning material, which is essential in controlling and extinguishing the fire swiftly and safely. This approach can prevent the fire from spreading and allows firefighters to manage the situation more effectively before considering surrounding cooling or removal of fuel sources.

In comparison, while cooling the surrounding area and removing the fuel source are also important phases in fire management, these steps are more effective when the immediate fire threat is controlled. Allowing the fire to burn out is not a safe or advisable strategy, as it poses risks of escalation or collateral damage. Prioritizing the application of AFFF ensures that the fire is contained as quickly as possible, aligning with best practices for handling Class B fires.