McALESTER, Oklahoma - Investigators are trying to figure what caused a McAlester apartment building to go up in flames.

Friday morning there were several things going on: an electric company worked  to restore the power in the area, the Fire Marshal was on scene investigating the cause of the fire, and firefighters had been out at the scene for nearly 20 hours putting out hotspots.

The top part of the building has six apartments and the bottom half is a shopping area.

Fire crews said four people were home when the fire started.

Thankfully, everyone was able to get out alive.

Main Street is currently closed from Wyandotte to Comanche.

A bystander shared video with News On 6 that showed the building is engulfed in flames.

Firefighters said people nearby jumped in to rescue people from the building, by getting them out through the windows. 

Officials said rescuers were backing trucks up to the building trying to reach the four people inside the apartments. 

Crews said everyone living in the apartments was accounted for, but two people were taken to the hospital by an ambulance. 

They said there were some others who took themselves to the hospital. 

Assistant Fire Chief Bent Brooks said when he first pulled up, he saw the flames and just hoped for the best. 

"This was a pretty big deal especially pulling up and seeing people hanging out windows. It's pretty traumatic seeing that. It's not something you see everyday and deal with" Brooks said. 

The plan now is to bring out heavy equipment to start knocking down the walls. 

Crews said no one is able to get inside right now because it is a safety hazard with the walls leaning over the rubble.