CHICAGO — Authorities in Chicago are trying to determine if carbon monoxide killed two women and sent six other people to the hospital.

The Chicago Fire Department responded to the building in the city's West Rogers Park neighborhood Sunday and rushed the two women to a hospital, where they died. Autopsies are planned on 77-year-old Rasheeda Akhter and 18-year-old Zanid Ahmed.

Emergency crews didn't find carbon monoxide in their initial tests. But the crews were called to the building again hours later when another person fell ill.