A fire burned at a biodiesel complex after an explosion that was felt kilometers away in northern Mississippi on Wednesday, a police official said, and while there were no reports of injuries, it was unclear whether all workers were accounted for.The fire began early Wednesday after an explosion, a dispatcher for the sheriff of Union County said. The Mississippi Highway Patrol said the fire was so hot, firefighters could not get close enough to fight it.Biodiesel refineries make fuel from a variety of non-petroleum products such as vegetable oil or animal fats.