A two-alarm fire swept through a Kansas City, Kan., apartment building late Tuesday, injuring five people and displacing 20 residents.

Firefighters pulled two of the injured people from their upper-floor apartment — one critically hurt and the other seriously injured.

“Firefighters thought everyone had escaped and were looking for the fire when they heard a female yell,” said Deputy Chief Craig Duke, a spokesman for the Kansas City, Kan., Fire Department. The noise led them to the injured residents, he said.

Two injuries came from medical complications, while the fifth injury involved someone falling down the fire escape, Duke said.

The fire was reported about 11:10 p.m. in the four-story building at 1215 Central Ave. Arriving firefighters saw heavy smoke and soon found all floors engulfed in fire, with flames burning through the roof.

As a precaution, firefighters left the building and fought the blaze in a defensive mode out of fear that the building would collapse.

William Way, who lived in an upper-floor apartment, said he was lying on his sofa watching television when someone started pounding on his door.

“When I opened the door, I saw smoke everywhere,” Way said. “I grabbed my phone and headed to the fire escape.”

The smoke was so thick, Way said, that he had to feel his way to where he remembered the fire escape was.

“I know I have nothing left in there,” Way said. “I don’t know if fire reached my apartment, but there is going to be a lot of water damage. I didn’t even remember to grab my wallet.”

Anna Hilt, who lived in an apartment with her son, Anthony Ortiz, his wife, Brittney Self, and their two children — Siarra, 15 months, and Alayna, 3 months — said they were just settling down for the night.

“We were lying down when we heard someone pounding on our door,” Self said.

It was a neighbor, Franklin Andrew Todd, who told them that they had to get out.

Self said they hadn’t smelled anything, but when they opened the door they saw the hallway was filled with smoke.

“I told them to grab the babies and you get out,” Hilt recalled, referring to her son and daughter-in-law. “I told them I would be right behind them. I grabbed what I could and exited the apartment.”

Once Hilt was in the hallway, the smoke was so thick she had to crawl to the fire escape.

“I thought I was going to die,” she said, beginning to tremble with tears welling.

On the way down the fire escape, people were throwing belongings. Something struck Ortiz, knocking him off balance and sending him tumbling down several steps.

He was taken to a hospital with injuries to ribs and an ankle, but the baby he was carrying was not harmed.

The structure is a former retail building that had been converted to apartments. It has two floors on the street level and a lower walk-out level on the back.

The building consists of 11 apartments and is home to 20 people. The Red Cross was called to assist them.

Investigators think the fire started in the rear of the building and quickly spread up and to the front. The city’s dangerous building department was called to begin tearing down the structure, which was a total loss of $250,000.

Fire officials were not aware of any working smoke detectors in the building.