CHICAGO (CBS) — A fire chief said he discovered a frightening and dangerous lack of working smoke detectors in homes in a suburban neighborhood after a fire left several people homeless last week.

Four brothers and sisters escaped a house fire on Dec. 20 in the 300 block of Division Street. They were treated for burns, smoke inhalation, and frostbite. Afterward, their mother said the children told her the smoke detectors in their apartment did not go off.

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Authorities said the landlord of the building had installed smoke detectors in the home, but they were not properly maintained.

Two days later, firefighters returned to the neighborhood to check whether other nearby homes had working smoke detectors. Crews found, of the 45 families they spoke to, 75 percent had either a non-functional smoke detector or no smoke detector at all. Firefighters installed 30 smoke detectors and provided 14 sets of batteries. In some cases, they installed multiple smoke detectors or provided batteries for multiple units.

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Elgin Fire Department Battalion Chief Terry Bruce said it was a sobering discovery.

“We are shocked to find that number of smoke detectors not working, yes,” he said. “I think people just get complacent, just like this family here. We know that they had working smoke detectors at one time. We don’t know what happened during the fire, but people just get complacent and don’t think that anything’s going to happen to them until it does.”

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Bruce said it’s a reminder to renters and homeowners to check that smoke and carbon monoxide detectors are not only installed, but working properly.