Which extinguisher type is specifically designed for cooking oils (Class K)?

• A. Water extinguisher is not designed for cooking oils.
• B. Class K extinguisher is specifically designed for cooking oils.
• C. CO2 extinguisher is designed for cooking oils.
• D. Dry chemical ABC is the only option for cooking oils.

Answer: (B)

Cooking oil fires demand an extinguisher that can both cool the hot fat and prevent it from reigniting. Class K extinguishers are designed for this exact scenario. They use a wet chemical agent (potassium acetate) that reacts with fats to form a soapy, gelatinous layer on the oil’s surface. This saponification creates a barrier between the oil and the air, cools the oil, and helps stop vapor release, which together extinguish the fire and reduce the chance of re-ignition. That specialized action is why Class K is the best choice for cooking oils.

Other options aren’t as effective for grease fires. Water extinguishers can cause the hot oil to splatter and spread the fire, or even cause a dangerous steam explosion. CO2 can displace oxygen but doesn’t reliably cool or blanket the greasy surface, so it often fails to suppress a grease fire. A dry chemical ABC extinguisher is versatile for many fire types, but it doesn’t provide the targeted saponification and barrier needed for fats, making it a less suitable choice for cooking-oil fires.