An Oakfield man was seriously injured in a fiery one vehicle rollover crash in Fond du Lac County. The crash happened at about 1am Thursday on County Highway I near Marsh Road. A preliminary investigation shows a car was south on I when it failed to negotiate a curve and struck a power pole and rolled over in a corn field. When deputies arrived the vehicle was engulfed in flames. The driver, a 35 year old Oakfield man, wasn’t wearing a seatbelt and was ejected from the vehicle. He was flown by helicopter to Theda Care Regional Medical Center in Neenah with serious injuries. Speed and alcohol are believed to be factors in the crash.