A 10,000-gallon diesel fuel storage tank exploded in western Pennsylvania Monday afternoon, killing one worker, authorities said. The 5:27 p.m. EDT blast and fire occurred in the Reynolds Industrial Park near Greenville, about 80 miles northwest of Pittsburgh, the Pittsburgh Tribune-Review reported. The tank belonged to Brownies Oil Co., a division of Reed Oil Co., the Pittsburgh Post-Gazette said. Mary Kress, 54, told the Post-Gazette she heard the explosion and saw a \"ball of flames.\" She said the tank hit a tree, bounced and landed near her home. Gary Clark, a spokesman for the state Department of Environmental Protection, said investigators were trying to determine whether the explosion may have been sparked by a welder working about 300 feet away from the above-ground tank. He said victim was believed to have been the welder. The Tribune-Review said company officials could not be reached for comment.