A four-flat apartment building was declared uninhabitable after a fire at about 7:30 on Wednesday night scorched the top floor and left the middle two severely water damaged.

Nobody was hurt in the blaze, as a neighbor and an off duty Chicago firefighter who was in the area managed to knock on doors and alert residents of the danger.

The neighbor, Teresa Garcia, was taking a cigarette break while watching the White Sox game on television when she discovered the fire.

“I came out to smoke and I saw flames coming out the back window,” said Garcia, who ran back inside to dial 911 before pounding on doors to help evacuate the burning building. She woke up a resident who was asleep in his apartment on the building’s bottom floor.

The top floor, which was most severely damaged, was unoccupied and nobody was home on the middle two floors. Forest Park Fire Chief Steve Glinke said the fire started on the back porch of one of the middle floors, but the cause is still under investigation.

“The whole building is going to require some level of restoration ” the top floor is completely gutted,” said Glinke.

Another witness, Ken Hartmann, who lives two blocks east on Hannah, was walking his dog in the alley behind Beloit when he saw the flames.

“The two rear windows were just gone,” said Hartmann. “The top of the roof, half way (to the front) was on fire.”

The top of a tall tree in the back yard was also engulfed in flames, he said.

All the residents who were displaced were able to find family members or friends to stay with, according to Glinke. Once it is determined to be safe, he said, the residents will be able to walk through the building accompanied by firefighters to recover any valuables that are still intact.

Glinke said the residents most likely will be displaced permanently, as renovations to the building, which was constructed in the 1950s, will have to comply with current village codes requiring each apartment to have two exits.

“They would have to retrofit the third floor with a second exit and de-convert one apartment on the middle floor,” he said.

The garden unit on the bottom floor is compliant with village code, said Glinke.

Glinke said firefighters from Forest Park, Oak Park, River Forest, North Riverside, Cicero, Berwyn, Stickney and Maywood responded after the officer in charge of the response, Mario Tricoci sent an elevated alarm.

He said that Forest Park’s department was fortunate enough to have 10 extra firefighters at the station because of a union meeting. If the response had not been as swift as it was, he said, damage could have been much worse.

“Certainly the body of fire was significant enough that if left unchecked it could have gone to properties on the north and south (of the building),” he said.

Garcia agreed, marveling at the speed with which the flames spread. “”It was like watching a napkin catching on fire,” she said. “The flames were so huge. It just went so fast.”

“I could feel the heat standing (four houses away),” said Hartman.

“Bill Dwyer contributed to this article