http://www.youtube.com/watch?v=yN8j0jmMA_g
This occured during the Daytona 500, NASCAR's Monaco Grand Prix basically.
Basically everyone was doing the thing they were supposed to do, JPM was trying to catch up with the field after he had pitted under caution when something broke on his car and he hit a jet engine that's used to clean up the track.
The person driving the truck was okay but was taken to the hospital for further evaluation
The race was red flagged for two hours while safety crews put out the fire and cleaned up the leftover fuel and repair the damaged part of the track.