Which property is critical to assess when sourcing fuel from outside the military supply system?

When sourcing fuel from outside the military supply system, flashpoint is critically important because it indicates the minimum temperature at which the fuel can vaporize to form an ignitable mixture in air. This property is vital for ensuring safety during handling, storage, and transportation of fuel. A fuel with a low flashpoint poses significant fire hazards, especially in military operations where conditions may not be controlled.

In contrast, while density can affect fuel efficiency and performance, it is not as critical for safety. Color and odor may provide some information about the quality or condition of the fuel, but they do not directly indicate safety risks related to combustion. Thus, assessing the flashpoint helps prevent potential accidents and ensures compliance with safety regulations when integrating external fuel sources into military logistics.