JP-4, or JP4 (for "Jet Propellant") was a jet fuel, specified in 1951 by the U.S. government (MIL-J-5624E). It was a 50-50 kerosene-gasoline blend. It's lower flash point than JP-1, but was preferred because of its greater availability. It was the primary U.S. Air Force jet fuel between 1951 and 1995. Its NATO code's F-40. It's also known as avtag. JP-4's a mixture of aliphatic and aromatic hydrocarbons. It's a flammable transparent liquid with clear or straw color, and a kerosene-like smell. I… (More on Jp-4)