Chicago authorities said Thursday that a deadly fire in a high-rise apartment building was caused by someone smoking in a bedroom.

In a brief statement, the Chicago Fire Department called the fire accidental and said investigators traced the cause to "careless use of smoking materials." Investigators also found that a smoke detector in the unit where the blaze broke out was not working.

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Chicago high-rise fire

A Wednesday fire that killed one person as it tore through a Chicago high-rise is believed to be accidental (AP Photo/Charles Rex Arbogast)

Wednesday's fire in the Kenwood neighborhood on Chicago's South Side killed one person and sent eight more to the hospital. Authorities have not released any information yet on the person who died.

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Fire Commissioner Annette Nance-Holt said Wednesday that fire detectors inside the building's apartments were battery-operated while those in the hallways were hard-wired.

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More than 300 fire and Emergency Medical Service workers responded to the blaze, which began on the 15th floor and traveled up to the 24th level as crews worked to contain it.