Witnesses said the middle-aged man wearing black pants and carrying a backpack set the fire with a bunch of newspapers after pouring volatile liquid at Cholsan Sation. The man allegedly fled the scene while other passengers evacuated the train car at Kwangmyung Station.

The subway train was stopped at Kwangmyung Station three minutes after the fire was first reported to the head office of the Seoul Metropolitan Rapid Transit Corp., which runs subway lines 5, 6, 7 and 8. Passengers evacuated immediately while subway station officials put out the fire with fire extinguishers.

However, as the empty subway train was heading to its final station at 7:25, the fire, which was believed to be extinguished, started up again and burned the last three rail cars of the train.