It's not oil, its molten aluminum judging from how bright and white the flame is and the fact that the machine is an aluminum bar extruder. People don't generally realize how insanely flammable aluminum can be when it is reduced to a fine enough powder. Powdered aluminum mixed with an oxidizer is what makes fire crackers go bang. It's also one of the two main ingredient in thermite.

I thought it might be oil or coolant. It pops off like a geyser and it was all over in seconds.