What is the recommended suppression approach for a small kitchen grease fire when a Class K agent is available?

• A. Use water to smother the grease.
• B. Ignore the fire and wait for it to burn out.
• C. Use a Class K wet chemical extinguisher; if not available, a Class B extinguisher with caution; never use water on a grease fire.
• D. Use a Class A extinguisher.

Answer: (C)

Using the right extinguishing agent for kitchen oil fires is essential because fats and cooking oils behave differently from other fuels. A Class K wet chemical extinguisher is designed for this exact scenario; its agent, typically potassium acetate, saponifies the oil, turning a burning fat into a soapy layer that cools, blankets the surface, and seals the fuel from air. This not only knocks down the flame efficiently but also helps prevent reignition in a kitchen environment where heat and oil can keep re-igniting.

If a Class K is not available, a Class B extinguisher for flammable liquids can be used as a backup, but with extra caution and proper technique—aim at the base of the flames and sweep, not at the top or from a risky distance. It’s not as ideal because oils can splatter and spread when using certain dry chemical or foam agents, increasing the risk of a larger flare-up.

Never use water on a grease fire. Water is denser than oil and will sink below the flame, rapidly turning to steam and causing the oil to explode outward, spreading the fire instead of controlling it. For very small fires, if safe, you can also smother with a metal lid or fire blanket and turn off the heat, but if the fire grows, evacuate and call emergency services.