Maine Maritime USCG Firefighting Practice Test

The appropriate type of fire extinguisher for fires involving grease, oil, chemicals, and gas is classified as Class B. Class B fire extinguishers are specifically designed to tackle flammable liquid fires, which include those caused by combustible materials such as oils, gasoline, solvents, and various chemicals. When deployed, these extinguishers work by smothering the flames and cutting off the supply of oxygen to the fire, which is crucial for extinguishing fires fueled by liquids that can easily spread and reignite.

Class A extinguishers are meant for ordinary combustible materials like wood, paper, and cloth, while Class C extinguishers are used for electrical fires. Class D extinguishers are tailored for combustible metals, which are not relevant in the context of grease, oil, or gas fires. Therefore, Class B is the correct choice for handling situations involving flammable liquids.