Which fire is often categorized as an unusual or uncontrolled incident?

An illegal fire is often categorized as an unusual or uncontrolled incident because it typically signifies a fire that is intentionally set without legal permission. These fires can include arson or other unauthorized burning activities that do not meet safety regulations or standards. Such incidents pose a greater risk to public safety, the environment, and property as they may occur in locations where management and control are absent. Illegal fires are unpredictable and can rapidly escalate due to their unregulated nature, which makes them distinct from more controlled or expected fire scenarios, such as structure fires, trash fires, or car fires. Each of these types of fires typically occurs within a specific context where some level of control or regulation exists, which is not the case with illegal fires.