The fire started Process_start under a wooden escalator serving the Piccadilly line and , at 19:45 , erupted Process_start in a flashover into the underground ticket hall , killing 31 people and injuring 100 .

The investigators reproduced Creating the fire twice , once to determine Deciding whether grease under the escalator was ignitable , and the other to determine Deciding whether a computer simulation of the fire—which would have determined the cause of the flashover—was accurate .

The inquiry determined Deciding that the fire had started Process_start due to a lit match being dropped onto the escalator .