What color is 100LL aviation fuel?

100LL aviation fuel, known as low-lead aviation gasoline, is dyed blue to distinguish it from other types of aviation fuel and automotive gasoline. The blue color helps pilots and refueling personnel quickly identify the fuel type, ensuring that they use the correct fuel for piston-engine aircraft. This is particularly important to prevent the potential for fuel contamination or incorrect fueling, which can lead to engine performance issues or even aircraft accidents. The distinct coloration system for aviation fuels is a key safety feature in aviation operations.