What is a potential hazard of a plane crash?

A potential hazard of a plane crash is a structure fire. This occurs because the impact of a plane crash can cause significant damage to nearby buildings or structures, leading to fires that may spread to the surrounding area. The fuel from the aircraft can ignite upon impact, creating intense flames that can easily catch nearby structures on fire, especially those made of combustible materials. The resulting structure fires can pose a substantial risk not just to the integrity of the building itself but also to any individuals in the vicinity.

The other options do not directly relate to the primary hazards associated with a plane crash. For example, a car fire typically pertains to a vehicle incident and isn't a direct consequence of an aircraft accident. A fire alarm, while potentially activated by a fire following a crash, is more of a safety measure than a hazard itself. An illegal fire does not have a clear connection to the scenarios surrounding an aviation accident, as it refers to unlawful actions rather than a direct result of the crash.