Fifty-one rail wagons carrying petrol, sulphur and fertilisers came loose and rolled out of control, eventually catching fire. As firefighters fought to control the blaze some five hours after the initial incident, the wagons exploded.
An estimated 450 people were injured in the blast and it is feared there are more victims buried in the rubble. Many of the dead were rescue workers. The government is demanding to know why the train was carrying such a lethal mixture of substances.