Oil jumps after explosion in massive fire at one of the largest U.S. oil refineries. An explosion in large plumes of smoke at the Valero refinery in Port Arthur prompted officials to order Westside residents to shelter in place, according to 12 News Now. A fire broke out in a diesel hydro treater with the unit suffering severe damage, according to people familiar with the incident. The fire was near the plant's fluid catalytic cracker, and part of the refinery has been shut down, according to the people who said a decision has not yet been made whether to shut the entire plant.