CHICAGO (CBS) — Flames broke out at a suburban condo complex, burning home after home for several hours Wednesday.

Fire officials have been working for eight hours to put out the blaze. They say they will continue working throughout the night.

“I just been standing here, watching my house burn down ever since,” said Monika Alvarez, a resident of the complex. “I never thought it would happen to me and my kids. Never.”

Alvarez, like so many others Wednesday, were forced to watch their Prospect Heights apartment complex burn before their eyes.

Chopper 2 was at the scene. From up above, smoke and flames could be seen ripping through the apartment complex.

The fire spread and destroyed three out of the four adjoining apartment buildings, each three-stories high. The Fire Chief says 96 units were completely destroyed in the fire.

Over 150 firefighters from more than 50 departments were called to the scene to try and contain the fire.

The flames started around 1:30 Wednesday afternoon and continued well into the night.

Fire officials say the building’s old construction created major challenges.

“It’s basically a glorified toothpick design. It’s structurally sound, except if there’s a big fire, it doesn’t perform well because it has no mass and fire resistance,” said Fire Chief Drew Smith of the Prospect Heights Fire Department.

The cause of the fire is unknown, but the Fire Chief says they’re looking into reports of a young boy home alone playing with matches or a lighter.

“We heard those reports and we will substantiate them or deny them as part of our comprehensive investigation,” stated Chief Smith.

“My son was home alone. Me and my husband were at work. I got the call from him that he had just jumped out of a window into an officer’s arms,” said Ashley Appleby through her tears. “It was my apartment. They don’t fully know what happened. But they said they know it started in my apartment.”

Two residents and a firefighter were treated for minor injuries.

Fire officials will be on scene dumping water on the site throughout the night.

Two residents and a firefighter were treated for minor injuries. Firefighters are continuing to battle this fire.

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The American Red Cross responded to the incident, as well. 15 volunteers immediately began setting up a reception center and canteen service to provide assistance, food, water, health services, and emotional support to people displaced by the fire.

A shelter has been opened for residents affected by the fire at Lakewood Chapel located at 1307 E. Palatine Road in Arlington Heights, IL. The shelter will provide for the immediate needs of the people involved and will remain open until all of the residents can be relocated.

The cause of the fire is under investigation.

CBS 2’s Dana Kozlov and Charlie De Mar contributed to this report.