Limited flights in and out of O'Hare and Midway international airports are resuming after a ground halt was ordered due to the local radar facility was evacuated because of smoke inside the building, CBS Chicago reported.
The Elgin TRACON (Terminal Radar Approach Control) facility was evacuated at about 11:30 a.m., according to a statement from the FAA. Elgin police said there was smoke coming from a faulty motor in an HVAC (Heating, Ventilation and Air Conditioning) unit at the facility.
As a result of the evacuation of the Elgin TRACON, a ground stop was issued at O'Hare International Airport and Midway International Airport, meaning all flights in and out of the airports were halted.
More than 600 flights at O'Hare and 75 at Midway with both airports still reporting significant delays as of 3 p.m.
All TRACON operations were transferred to the Chicago En Route Center in Aurora.
TRACON workers were allowed to return to the building around 1 p.m. after firefighters deemed the building was safe and there was no fire, but it was unclear how soon air traffic would resume at O'Hare and Midway.
Long lines of airplanes could be seen sitting on the taxiways at O'Hare as they waited to take off. Flights that have been waiting to land at the airports were being diverted to other airports as needed.
"This is both airports, so it's a big problem," said Joe Schwieterman, an aviation expert with DePaul University.
He said if the ground stop continues much longer, it could be major issue for airports across the country.
"We have a lot of flights going out to the East Coast, so once that backs up, it could ripple through the day, and if this goes on a couple hours, of course, it will be a bit of a meltdown situation," Schwieterman said.
Heidi Werner was one of many passengers stuck on a plane because of the ground stop in Chicago. She was flying home after several months in Brazil, but her flight to O'Hare was diverted to Milwaukee. Her father was at O'Hare waiting to pick her up. Ironically, he works near the Milwaukee airport, but drove to Chicago on Tuesday to pick her up at O'Hare.