Which fire extinguisher type is not recommended for flammable liquid fires?

Water is not recommended for extinguishing flammable liquid fires because it can cause the fire to spread rather than extinguish it. When water is applied to a flammable liquid fire, it may not effectively cool the burning liquid or remove the heat necessary to extinguish the flame. Instead, water can cause the burning liquid to float on top and potentially spread to other areas, thus exacerbating the fire hazard.

In contrast, carbon dioxide, foam, and dry chemical extinguishers are effective for flammable liquid fires. CO2 works by displacing oxygen, which is essential for combustion, thereby suffocating the fire. Foam creates a barrier between the flammable liquid and the air, preventing re-ignition while smothering the flames. Dry chemical extinguishers interrupt the chemical reaction of the fire by coating the fuel with a powder that prevents combustion. This makes the other options suitable for handling flammable liquid fires, as they target and mitigate the fire safely and effectively.