A Coast Guard report says a passing tugboat helped spark the massive explosions that rocked the Mobile River and injured three people in April.
A preliminary report says workers were cleaning fuel storage tanks on two barges moored at Oil Recovery Co. in Mobile on April 24.
The report says flammable vapors from the barges entered the engine room of the towing boat Safety Runner, causing a brief fire. Investigators believe the flames traveled back to the barges and resulted in the explosions.
The blast injured three workers and caused a 30-gallon oil spill in the Mobile River. Seven separate explosions occurred after the accident.
One of the injured workers filed suit days after the explosion, and that lawsuit is pending in Mobile.