Four people have been confirmed dead following an explosion on Thursday when a barge collided with a natural-gas pipeline off the Louisiana coast, the U.S. Coast Guard said Friday. Rescue workers were still searching for two people who were listed as missing. The accident occurred when a tugboat and two barges ruptured a natural-gas pipeline belonging to Gulfport Energy near the company's West Cote Blanche Bay oil and natural-gas field. Gulfport announced Thursday that the field, which pumps about 4,000 barrels of oil equivalent per day of oil and gas, was shut down.