What is the primary hazard of using water on a grease fire?

Using water on a grease fire is particularly hazardous because it can create a steam explosion. When water is poured onto a grease fire, it can rapidly evaporate due to the extreme heat of the burning oil. This rapid conversion of water to steam expands significantly, often causing the burning grease to splatter and spread the fire in an unpredictable manner.

In contrast, the other options do not accurately reflect the consequences of using water on a grease fire. While someone might think that water could extinguish the fire quickly, it actually exacerbates the situation. Cooling down the area is also not effective because the heat from the burning grease can easily reignite or continue to burn, negating any cooling effort. Thus, understanding the specific reaction between water and grease, and recognizing that it leads to the potential for a steam explosion and fire spread, is critical for fire safety and proper fire extinguisher techniques.