Just my amateur observation but usually HE gives a smokey grey explosion while fuel will give you the “Hollywood” orange fire ball.
HE usually has a large fireball but on the ground dust often obscures it from view. If you have seen some of the video of the IDEs used in Iraq and Afghanistan, you’ll usually see large fireballs from the large quantities of explosives used. That explosion says “HE” to me and I have been on both ends of that stuff much of my life.