HazMat situation prompts evacuation of Near North Side building
![firetruck_1446223471282.jpg](https://images.foxtv.com/static.fox32chicago.com/www.fox32chicago.com/content/uploads/2019/08/764/432/885cb028-firetruck_1446223471282_415272_ver1.0_640_360.jpg?ve=1&tl=1)
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CHICAGO (Sun-Times Media Wire) - A hazardous materials situation prompted the evacuation of a Near North Side office building early Thursday afternoon.
The Chicago Fire Department responded to a Level One HazMat situation at 770 N. LaSalle, Fire Media Affairs tweeted at 12:14 p.m.
The carbon monoxide was initially measured at 200 ppm and the HazMat was elevated to a Level Two, according to Fire Media.
The building was evacuated, according to Fire Media. The source of the carbon monoxide was a gasoline-operated air-conditioning generator being used on the first floor of the building by a construction crew.
About 12:50 p.m., air quality returned to normal and crews were released from the scene.
CTA buses were also temporarily rerouted in the area.