The fire started around 1 p.m. Sunday at an apartment building on Van Ness and Voorman in Downtown Fresno.
Fire officials say the 19-year-old is awake and alert but suffered smoke inhalation.
The building was destroyed in the fire. At one point fire fighters thought parts of the building would collapse.
Cell phone video captured the huge flames shooting out of this structure. Fire investigators say the flames first burned downstairs.
Kevin Linder recorded the video.
"It was just a scary feeling for the people that live there. Losing their homes like that is pretty sad," Linder said.
Witnesses say fortunately they didn't lose more.
The owner of Barr Brothers, a dress shop across the street, ran to the burning building to warn the family inside.
Seeing the fire, she wanted to get people out of there. The heroic owner was too shaken up to be interviewed on camera but Kandy Mendoza says she's proud of her boss.
"She's a very brave lady. It would take so much for a person to go over there and save people's lives," Mendoza said.
The family living in the apartment didn't want to talk on camera either. They told Action News they're grateful they were not injured.
But their 19 year old cousin was. He ran out and told officials the fire started in his apartment.
"Then he returned to the apartment through the backdoor and succumbed, in the fire, to the smoke. Fire fighters then found him in the apartment unconscious," Deputy Chief Tim Henry of the Fresno Fire Department said.
Now he's said to be doing fine. Firefighters say the flames and heat at one point became too intense for them to stay in the roughly 100-year-old building.
So they sprayed water from a ladder truck.
"It was not designed as a multi-family house. So the add-ons and the changes made it difficult to get to where the fire is at," Henry said.
The Red Cross is here assisting those who lost their home. Investigators say they have not yet determined a cause for the fire since they have not yet interviewed the teenager who said it started in his apartment.