All flights in and out of Chicago's O'Hare International and Midway airports were grounded because of smoke inside a regional air traffic radar facility serving northeastern Illinois, the Federal Aviation Administration (FAA) said Tuesday.
The FAA said in a brief statement that all FAA personnel were evacuated from the Terminal Radar Approach Control Facilities, or TRACON, in Elgin, Illinois, at 11:30 a.m., Xinhua reported.
The FAA said that the cause of the smoke had not yet been determined, and all operational capacity has been transferred to a facility called the "enroute centre" in Aurora Illinois.
More than 350 fights have been canceled and about 700 flights delayed at the O'Hare International airport, the second busiest in the US and a major transit hub, with about half of passengers there connecting to other flights, according to Flightstats, which tracks airline operations.
The ground stop resulted in less severe disruptions at Midway airport, with about 20 flights canceled and around 110 delayed, according to Flightstats.
