The largest oil refinery in the U.S. prepared to shut down production Tuesday following damage from Tropical Storm Harvey. The Port Arthur refinery, owned by Motiva Enterprises, is home to more than 15 percent of the nation’s refining capacity and processes more than 600,000 barrels per day. By Tuesday night, the refinery was running at 40 percent of normal production. A nearby Valero facility, Exxon Mobil’s refinery in Beaumont and Marathon Petroleum’s refinery in Galveston Bay were also operating at reduced capacity and planned to shut down temporarily, according to reports. With about 3.9 million barrels of refining capacity offline due to Harvey, gasoline futures prices surged a two-year high in New York trading. Analysts have warned drivers to prepare for a 15-cent per gallon jump at the pump, with increases as high as 30 cents in some Gulf Coast areas.