The smoldering phase of fire progression is characterized by which of the following?

The smoldering phase of fire progression is primarily characterized by a slow, low-temperature combustion. During this phase, the flames have typically died down, and combustion takes place at a temperature lower than what is seen in the active burning phase. This low-temperature combustion occurs without visible flames, and combustion mainly takes place in a solid or liquid state, often producing smoke and a significant amount of carbon monoxide as by-products.

It is a critical phase as it can last for extended periods, and if the conditions are right (such as an increase in available oxygen), it can reignite into an active flame. Understanding this phase is essential for fire officers because it influences decisions on fire suppression tactics and safety protocols, particularly in scenarios where hidden fires can flare back to life unexpectedly.