The sewers did n't cope to large quantities of water , thus several streets were flooded Catastrophe .

Four days before the explosion Catastrophe , residents started Process_start complaining Judgment_communication of a strong gas-like smell coming from the sewers which became Becoming progressively more pungent over the course of those days .

City workers were dispatched Sending to check Scrutiny the sewers and found Know dangerously high levels of gasoline fumes .