TULSA, Oklahoma - A 1-year-old boy died in a Tulsa apartment fire and 7-year-old is in critical condition.

Whole walls were eaten up by the flames and the back stairwell is gone at the Sand Dollar Apartments near 61st and Riverside. It's a stark reminder of the tragedy that hit the complex overnight.

Don Pearce was asleep in his recliner when someone started pounding on his front door. He woke up to a room full of smoke.

"You could smell it, I couldn't breathe," he said. "We got out of there."

Pearce went outside and found his building on fire and dozens of first responders rushing to the scene.

"That's all you could smell and see was smoke," said Pearce. "If I had been alone I probably would've slept through it."

But not everyone made it out safely.

Six people were taken to the hospital - firefighters believe five of them were living in one unit hit hardest by the flames.

It took just four minutes for the first firetruck to get to the scene; several other stations, plus police and ambulances followed.

Neighbors said it didn't take long for first responders to start knocking on doors warning residents nearby to be aware that the fire could spread.

At least eight apartment units were evacuated as firefighters fought the flames for more than two hours.

Four units have fire damage and four others have smoke damage. Residents are now dealing with the aftermath.

"It could've taken the whole building," Don Pearce’s wife said.

But, thankfully, it didn't - a firewall in the Pearce's building helped stop the flames from spreading.

The Fire Marshal is investigating what caused the fire.