UPDATE (10:30 PM) - Peoria firefighters said Tuesday night the fire on West Willowlake Drive was accidental.
One of the residents was taken to the hospital for treatment of heat exhaustion. No firefighters were hurt.
The American Red Cross was called in to help find places to stay for residents of seven of the 12 apartments.
A dollar estimate of damage is not available.
PEORIA (HOI) -- Fire at a multi-story apartment complex in the 2700 block of West Willowlake Drive necessitated a call for extra units Tuesday.
Peoria Fire Department Battalion Chief Michael Hughes said first-arriving units stated they had heavy fire coming from the third floor back of the apartment complex.
Because of the occupancy level inside the three-story building, Hughes called for extra units.
"All three floors had to be checked, we had two crews just doing a search, we had two crews going in for suppression, we had a crew securing utilities," he said. "We have multiple crews and it is very hot also, but we're here for any amount of time we're going to be so we will start rotating crews just because of the heat."
Hughes said it sounded like the fire was contained to one apartment along with the attic. He said there was nobody found inside the apartment and it was unknown whether someone was inside at the time of the fire.
He said investigators were already on scene. The fire was put out and firefighters were doing ventilation and salvage and overhaul on the lower floors.
Damage and living conditions have yet to be assessed.