Which stage occurs when the fire has used up much of its fuel or oxygen and begins to spiral toward extinction?

• A. Incipient Stage
• B. Decay Stage
• C. Growth Stage
• D. Fully Developed

Answer: (B)

As a fire begins to wind down after its peak energy release, it enters the stage where the available fuel or oxygen has been largely used up. In this decay stage, combustion slows significantly because there isn’t enough fuel to sustain rapid growth or enough oxygen to keep flames strong. The fire tends to lose intensity, heat release drops, and smoke can become more pronounced as hot gases linger. Because conditions are cooling and fuels are dwindling, this is the time when extinction is likely, though introducing air can still trigger dangerous re-ignition if hot, unburned gases are present (a backdraft risk). The other stages describe growth and full involvement of fuels, leading up to maximum intensity, so they don’t fit the description of a fire spiraling toward extinction.