There have been instances where the engine of a tractor trailer begins to run away, eventually resulting in an explosion. In one case that ARCCA was involved with, the explosion occurred at a petrochemical handling facility. Our expert conducted a site inspection and found that the environment next to the truck contained hydrocarbons. Since hydrocarbon fumes hover at roughly 36 inches or below, he determined that the diesel engine breathed in the hydrocarbons, causing it to go full throttle and eventually explode.