How can a Class "B" fire be most effectively extinguished?

To effectively extinguish a Class "B" fire, which involves flammable liquids such as oils, gasoline, and solvents, the best method is to smother the burning liquid. This action deprives the fire of oxygen, which is one of the essential elements needed for combustion. When a fire is smothered, the flames are suppressed because the supply of oxygen is cut off, preventing the fire from continuing to burn.

Using methods that focus on cooling, like lowering the temperature of the burning liquid, may not be as effective since many flammable liquids can reignite even after cooling. Similarly, attempting to lower the temperature of burning materials like wood or paper pertains more to Class "A" fires, which involve ordinary combustibles. Creating a chain reaction between molecules is not a viable fire suppression technique within this context.

Therefore, smothering the burning liquid is the most efficient and effective way to extinguish a Class "B" fire and prevent its spread.