What is one reason that oxygen is critical in the context of fire?

Oxygen is essential in the context of fire because it fuels the combustion process. Fire requires three components to ignite and sustain: fuel, heat, and an oxidizing agent. In most fires, that oxidizing agent is oxygen. When oxygen is present, it reacts with the fuel (which can be wood, paper, or other combustible materials) at a sufficient temperature to produce heat and light – the very essence of fire.

Without adequate oxygen, the combustion reaction cannot occur efficiently, and the fire cannot sustain itself. Thus, the presence of oxygen is critical not only for the initiation of fire but also for its ongoing ability to burn. This understanding is fundamental in both fire safety and firefighting strategies, where controlling or reducing the level of oxygen can help extinguish fires.