The explosion triggered a fire that blew off one of the oil storage tanks metal lid. The blaze was quickly put out, said Commander Charlie Rances, a Coast Guard operations officer.
"The tanker was already empty and they were just cleaning remnants of oil so we need to find out if someone smoked or what it was that caused the explosion," Rances added.
He said the MT Hagonoy with 497 gross tonnage was moored in Binondo when the explosion occurred. The blast shook several nearby buildings.
Four crewmen cleaning the tank were taken to a hospital for second and third-degree burns, Rances said. The explosion occurred shortly after the tanker had unloaded its cargo of 1.1 million liters of gasoline. Edu Punay, AP