Explosives
A truck overturned near Salt Lake City in August, 2005. Other drivers went over to the truck to help and the crew got out OK. But the driver quickly shouted to the bystanders that his load was 35,000 lbs. of explosives, so everybody ran. About 3 minutes later, the truck exploded creating a 30-foot deep crater in the road, blasting chunks out of the canyon wall, setting brush fires, and damaging a Union Pacific rail line.
Originally from the Salt Lake Tribune