On February 18, 2025, a fire broke out in the engine room of the towing vessel Thor while it was pushing two barges down the Delaware River. The incident occurred at approximately 09:25 when the vessel was located 1.5 nautical miles (2.8 kilometres) downriver from New Castle, Delaware.
Four crewmembers, including a captain, mate, engineer, and deckhand, were on board the Allegiant Tug Company vessel at the time of the emergency.
According to the National Transportation Safety Board, the captain first detected smoke billowing from a stack and noticed a metallic smell shortly after the vessel passed under the Delaware Memorial Bridge. The engineer and mate were ordered to investigate the engine room, where they discovered the space was filled with heavy black smoke.
Following the discovery, the crew sealed hatches and ventilation to the engine room in an attempt to contain the blaze. The captain issued a mayday call and successfully manoeuvred the tow outside the Delaware River channel.
As the fire intensified, the captain lost steering because the associated cabling was damaged by the heat. Before abandoning the 71-foot-long (21.6-metre) tug to the barges, the captain and engineer pulled emergency fuel stops for the main engines and generators.
The crew was rescued by the towing vessel Wye River at approximately 10:00. Allegiant Tug Company reported that there were no injuries and no pollution resulted from the accident.
The Wilmington Fire Department brought the fire under control by 12:00, though damage to the vessel was estimated at $1.5 million.
A post-casualty examination by the National Transportation Safety Board and the Bureau of Alcohol, Tobacco, Firearms and Explosives identified that the fire likely originated in the port corner of the engine room's upper level. Investigators found a paint locker in the area, along with a boot warmer plugged into an extension cord.
The National Transportation Safety Board determined that the probable cause of the fire was an undetermined ignition source in the upper level of the vessel’s engine room. Although investigators noted that an electrical fault could have produced sufficient heat to ignite nearby combustibles, the exact cause was officially classified as "undetermined" due to the extent of the damage.