The driver's father said it was a mechanical malfunction of the truck. I first thought the pyrotechnics must have ignited the fuel in the truck, but apparently that wasn't the case. I found a better video that shows flames erupting from the truck and the truck going into a right power slide before reaching the pyrotechnic fireball.
https://www.youtube.com/watch?v=VkmBndIVKY0Looks like the same thing happened 14 years ago, also to Shockwave:
https://www.youtube.com/watch?v=TKNAc9pN-U0
