UPDATED 09/05/12 2:48 p.m.

CHICAGO (CBS) — A condo building on the city’s Northwest Side was evacuated Wednesday afternoon, after carbon monoxide levels rose into the danger zone.

The Fire Department just before noon called a Level 2 Hazardous Materials response at the condo building at 4106 N. Narragansett Ave., in the Dunning neighborhood.

LISTEN: WBBM Newsradio’s John Waelti reports

The source of the leak was a cleaning crew that left a truck idling in the basement garage of the building.

Firefighters as of 1 p.m. were knocking on doors and evacuating residents. The response was quickly, said spokesman Larry Langford.

“We didn’t have people complaining of injuries. The level was grabbed before it got that bad,” Langford said.

Langford called it all a simple case of negligence.

The building had to be force-ventilated before neighbors could be let back in.

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