CHICAGO (CBS) — Part of the Cook County Jail has been without heat for days.

CBS 2’s Dorothy Tucker reports one tier in Division 4 – the women’s division – lost heat on Saturday, so the 10 inmates housed there were moved to other areas of the jail.

The night the heat went out on that tier, the outside temperature dropped to as low as 12 degrees in Chicago.

According to the Cook County Sheriff’s office, the 10 inmates on the tier were given extra blankets right away, after the heating unit malfunctioned. The tier was shut down and those inmates were moved to other tiers with heat, while county engineers worked on repairing the broken heating unit.

The sheriff’s office said a heating vent was obstructed, preventing that tier from getting heat. It was unclear when heat would be restored to the affected tier, but the sheriff’s office said no inmates would be housed there until the problem is solved.