What does the letter “K” signify on a fire extinguisher label?

The letter "K" on a fire extinguisher label specifically signifies that the extinguisher is designed for kitchen fires, particularly those involving cooking oils and fats, which are classified as Class K fires. These types of fires require extinguishing agents that can effectively cool and smother the flames, preventing them from reigniting. Class K extinguishers utilize special wet chemical agents that can break down the oils in these fires, making them highly effective in a kitchen environment where such flammable materials are present.

The other options pertaining to the intended use of the extinguisher do not accurately reflect the purpose of a Class K extinguisher. Extinguishers designed for flammable liquids are typically labeled with the letter "B," and those labeled for general purpose will be indicated as such rather than a specific class. The reference to chemical hazards does not apply to a Class K extinguisher, as they are specifically focused on the types of fires that arise in cooking scenarios.