The Duluth Fire Department responded to a structure fire in the Endion neighborhood early Thursday morning. Crews responded to reports of an apartment fire around 3:45 a.m. on the 1900 block of Jefferson Street. Flames could be seen coming from a ground-floor window of the building. Fire crews knocked down the flames quickly and contained the fire to one room. No injuries were reported. Two residents are displaced as a result of the fire. Damage is estimated at $7,000. The cause of the fire is under investigation.