What is the main hazard of using water on a Class B fire?

Using water on a Class B fire, which involves flammable liquids such as gasoline, oil, or solvents, poses a significant hazard because water can cause the burning liquid to spread. When water is applied to a Class B fire, it can mix with the flammable liquid, leading to an increase in the surface area of the burning material and allowing the flames to extend further. This spreading effect exacerbates the situation, making the fire larger and more difficult to control.

In contrast, while water can cool flames and decrease fire intensity, this is not only ineffective on Class B fires but also dangerous as it increases the likelihood of fire spread. Additionally, while water is a common and effective extinguishing agent for Class A fires, it is not suitable for Class B fires, where specific extinguishing agents are required to safely suppress the blaze without causing further hazards. Understanding these principles is vital for fire safety and effective fire suppression strategies.