Ignite Your Future with the 2025 NFPA Certified Fire Inspector I Test – Blaze Through It!

The correct response is carbon dioxide (CO2) because it effectively extinguishes fires by displacing oxygen in the environment around the fire, thus smothering it. When carbon dioxide is released from a fire extinguisher, it forms a gaseous blanket that envelops the flames, reducing the availability of oxygen that is crucial for combustion. This smothering action is particularly effective on class B and C fires, which involve flammable liquids and electrical equipment, respectively.

In contrast, water is primarily effective by cooling the fire and reducing the temperature below the ignition point. Foam also serves to smother fires, but it works primarily by forming a film over the burning material rather than creating a gaseous blanket. Dry chemical agents extinguish fires through a combination of interrupting the chemical reaction of combustion and forming a barrier between the fuel and the oxygen; however, they do not provide the smothering action associated with a gaseous blanket like carbon dioxide does. Thus, carbon dioxide is distinct in its method of extinguishing fires through oxygen displacement, making it the correct answer.