At least 15 people have been killed and more than 100 injured when a thunderous explosion tore through a BP oil refinery in Texas. The blast shot flames and billowing smoke into the sky and showered the area with ash and chunks of charred metal. Workers searched into the night through rubble for survivors or bodies, several hours after the blast. An undetermined number of workers were unaccounted for; most of the injured suffered broken bones, cuts, concussions and other injuries. The blast left a gaping hole in the earth, mangled nearby offices, and was so powerful that witnesses said it rattled homes as far as five miles away. Cars and trucks in an employee car park were coated with soot and debris.