JUNE 17, 2013 — Coast Guard Sector Mobile has released preliminary findings from its continuing investigation into the cause of the April 24, 2013 explosions and fire on board two Kirby tank barges while moored at the Oil Recovery Company Marine Terminal in Mobile. (See earlier story).

On the evening of April 24, Oil Recovery Company personnel were conducting tank-cleaning operations on both tank barges. The barges previously held natural gasoline, a flammable liquid and a first distillation of crude oil. The tank-cleaning processes involved pumping as much cargo residue as possible from the cargo tanks and using mechanical blowers to ventilate and dry the tanks of remaining oil and flammable vapors. During this process, Oil Recovery Company personnel discovered a malfunctioning mechanical blower, which required them to shut down all the blowers to effect repairs. In shutting down the blowers, flammable vapor from the cargo tanks accumulated around the tank barges and settled on the water's surface next to the barges.

At this time, the towing vessel Safety Runner pulled into the same pier at the Oil Recovery Company facility. As the towing vessel approached in close proximity to the tank barges and the cleaning operation, the flammable vapor traveled through the engine room's ventilation and into its main engines and engine space. Flammable vapors accumulated in the engine room, ignited, and caused a brief fire. The resulting fire spread across the accumulated flammable vapors from the towing vessel and back to the adjacent tank barges. This chain of events caused the flammable vapors within the tank barge's cargo tanks to explode and engulf the barges in fire.

The City of Mobile Fire Department, local harbor tugs fitted with fire monitors, and the Coast Guard responded to the scene. The fire department contained the fire to the tank barges and later extinguished the fire by early the next morning.

The resulting explosions and fire critically injured three persons (an Oil Recovery Company worker, and two persons aboard the towing vessel), created a 30-gallon oil spill in the Mobile River, caused fire damage to the tug and destroyed the two tank barges.

The purpose of the Coast Guard's investigation is to identify contributing factors that led to the incident and take appropriate measures to assist in preventing future marine accidents.

The Coast Guard is leading the marine casualty investigation on behalf of the National Transportation Safety Board. Using Coast Guard factual material and evidence gathered in this major marine casualty, the NTSB will develop an accident report establishing probable cause.