CHICAGO (CBS) — An extra-alarm fire in Kankakee early Wednesday left two boys in critical condition, and several other people injured.

When firefighters arrived at the two-story building in the 800 block of West Station Street around 1:50 a.m., some people living in the apartments over two storefronts were trapped inside, because the flames had blocked access to the rear stairwell.

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Kankakee Fire Chief Ron Young described the chaos when firefighters arrived.

“One civilian pulled his van next to the building, and tried to assist people out the window on the van, and one person jumped out of the window, so it was very chaotic,” he said.

Fire officials said more than half of the 22 people who lived in the building were rescued from the second floor using ladders.

Two boys, ages 2 and 4, were badly burned and were unresponsive when ambulances rushed them to hospitals in Kankakee. They were then airlifted to other hospitals in critical condition. The 2-year-old was taken to Loyola University Medical Center in Maywood, and the 4-year-old was breathing on a ventilator when he was flown was taken to Comer Children’s Hospital at the University of Chicago.

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Two women and a man were taken to Riverside Medical Center in Kankakee with injuries from the fire. A 25-year-old man suffered burns to his face, and a fracture from jumping out a window; a 22-year-old woman suffered burns to her hands, and a 55-year-old woman suffered from smoke inhalation.

One firefighter was treated at the scene for minor burns to his face, and went back to work.

Young said the fire was put out about 90 minutes after it started. It appeared to have started in a rear stairwell, near a laundry room and a store room, he said. The cause of the fire has not yet been determined.

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The American Red Cross was helping the two dozen residents who were displaced by the fire.