 According to CSX, which operates the rail system, two boxcars loaded with paper derailed near Mattawamkeg. One of the spills sideswiped the fuel tank of the engine, rupturing it and causing the spill. Maine's Department of Environmental Protection says cleanup crews managed to safely transfer about 2,500 gallons from the fuel tank and worked to clean up the 1,200 gallons that had spilled onto the ground. No oil entered the nearby Penobscot River.