Police car lightsAuthorities say four Waterloo residents had a very close call late last night.

Reports say the power went off in the house and one resident hauled a gas-powered generator into the laundry room and fired it up.

A door and a window were left open, but within a half-hour, the fumes became overpowering.

One resident called 911 about 11 PM and when firefighters arrived, they found one person unconscious in a doorway.

That woman, her two roommates and a 15-month-old child were rushed to University Hospitals in Iowa City for carbon monoxide poisoning.

All four are expected to survive.