COLUMBUS, OHIO ? An overheated extension cord sparked a house fire early Friday that killed a teenager and her three young children in an upstairs room, authorities said. The youngest victim was 2 weeks old.

The teen’s father and five other people escaped.

Investigators determined the fire was accidental, caused by the extension cord that ran downstairs from a space heater on the second floor, according to the fire department. Firefighters found no working smoke detector in the house.

Ten people were inside the four-bedroom home when the fire started around 5:30 a.m.

The teenager’s father, Paul Sadler Sr., said he smelled smoke and tried to save his daughter and her children, but it was too difficult.

Fire officials identified the dead as Mindy Hanners, 19; Katelynn, 4; Austin, 1; and Nevaeh, 2 weeks.

Two firefighters were treated for burns.