On May 18, 2021, about 0653 local time, the towing vessel Mary Lynn, with a crew of six, was pushing two barges, transiting upbound near mile 176 on the Upper Mississippi River near St. Louis, Missouri, when a fire broke out in the engine room. A nearby Good Samaritan towing vessel and a St. Louis Fire Department fire boat helped put out the fire, which was extinguished at 0810. There were no injuries or pollution reported. Damage to the Mary Lynn was estimated at over $700,000.
The probable cause of the engine room fire on board the towing vessel Mary Lynn was the overpressurization of the fuel day tank (which did not have an independent vent) and a main engine fuel return system when the fatigued chief engineer inadvertently left the day tank overflow valves to the storage tanks closed, which ultimately led to ignition of spraying diesel fuel from a main engine’s fuel system onto an uninsulated engine component.
