(Updates with fire still burning, adds details, byline, changes dateline to Wynnewood, previous CORPUS CHRISTI) By Ben Fenwick WYNNEWOOD, Oklahoma, April 28 (Reuters) - A massive fire that shut Gary Williams Energy Corp.'s 50,000 barrel per day (bpd) refinery in Wynnewood, Oklahoma, continued to rage late on Saturday, raising a thick column of black smoke visible for 25 miles (40.2 km). Wynnewood Police Chief Ken Moore said firefighters were waiting for the 20,000 barrels of diesel fueling the blaze to burn before they would attempt to extinguish any burning structures near a giant storage tank that exploded on Friday at 8:30 p.m. CDT (0130 Saturday GMT). "It should burn out a foot an hour and there was 25 feet in it, so it should be 24, 25 hours," Moore said at a road block outside the refinery 66 miles (106 km) south of Oklahoma City. Refinery managers decided on Friday night to perform a controlled shutdown of the refinery's production units as the fire threatened to burn through power lines providing electricity to the plant, said Sally Allen, Gary Williams' vice president of administration. "We don't know when it will restart," Allen said. "We really don't know. We are starting to plan for it." None of the process units were thought to have been damaged in the explosions, fire or in the shutdown, she said. The fire, which started with a lightning strike on a storage tank shortly before noon Friday, igniting 50,000 barrels of naphtha, will have to die before the restart will be attempted, Allen said. Burning naphtha spread to the diesel storage tank on Friday night. No one was injured in either explosion or in the fire, which was sending flames 60 feet into the air on Saturday. Emergency monitoring teams for the U.S. Environmental Protection Agency have been checking for pollution from the fire since Friday afternoon and have not detected any pollution spreading beyond the refinery grounds, she said. Firefighters from communities near Wynnewood have been assisting the city's and refinery's firefighters, she said. Firefighters from Valero Energy Corp.'s Ardmore, Oklahoma, are among those assisting with firefighting efforts. The Wynnewood refinery provides gasoline, diesel and jet fuel to mid-North America markets. It draws oil from the Cushing, Oklahoma, hub, which has developed a glut of West Texas Intermediate crude following the Feb. 16 fire that shut Valero's <VLO.N> 170,000 bpd McKee refinery in Sunray, Texas.
