Updated: 6:45 p.m. | Posted: 7:19 a.m.
All flights in and out of Chicago's two airports were halted Friday after a fire at a suburban air traffic control facility sent delays and cancellations rippling through the nation's air travel network.
The Chicago shutdown has forced the cancellation of at least two dozen flights from the Minneapolis-St. Paul International Airport.
• MSP airport: Check your flights
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MSP airport spokesperson Pat Hogan said about 9,000 people on about 80 flights a day normally travel between the Twin Cities airport and Chicago.
"People who are just going to connect through Chicago to other cities can often find other routes to get to their destination," Hogan said. "But if you're flying to Chicago, or from Chicago to MSP, it's not going to be a good day."
Hogan said flights in and out of Chicago will likely be affected for at least a few days as airlines deal with the passenger backlog created by today's cancellations.
As of 4 p.m. Friday, Delta Air Lines reported nearly 300 mainline and Delta Connection flight cancellations across the carrier's network as a result of the fire.
Both O'Hare and Midway Airports in Chicago have yet to return to full service. It is unclear when they will.
Delta says it is evaluating how many of its flights will go through Chicago.
The carrier will allow customers with tickets for travel Friday or Saturday and itineraries involving a dozen Midwestern cities to re-book and travel by Oct. 1 with no fee.
• For updates: @DeltaNewsroom on Twitter
Service to several cities in Illinois, Iowa, Wisconsin and Michigan were affected, and eligible for the waiver, because the damaged FAA facility controls high-altitude airspace there, as well:
• Bloomington, Ill.(BMI)
• Cedar Rapids, Iowa (CID)
• Chicago-Midway (MDW)
• Chicago-O'Hare (ORD)
• Fort Wayne, Ind. (FWA)
• Grand Rapids, Mich. (GRR)
• Kalamazoo, Mich. (AZO)
• Madison, Wis. (MSN)
• Milwaukee (MKE)
• Moline, Ill. (MLI)
• Peoria, Ill. (PIA)
• South Bend, Ind. (SBN)
Authorities said the blaze in Chicago was intentionally set by a contract employee of the Federal Aviation Administration and had no ties to terrorism. More than 850 flights had been canceled in Chicago alone and many more were expected.
The early morning fire forced the evacuation of the control center in Aurora, about 40 miles west of downtown Chicago. Emergency crews found the man suspected of setting the fire in the basement, where the blaze began, with a self-inflicted wound. He was taken to a hospital.
Aurora Police Chief Gregory Thomas said the fire was not a terrorist act. The FBI, the Bureau of Alcohol, Tobacco, Firearms and Explosives, and local police and fire departments were investigating.
When the center was evacuated, management of the region's airspace was transferred to other facilities, according to FAA spokeswoman Elizabeth Cory.
Authorities said it was unclear how long the stoppage would last.
Aurora spokesman Dan Ferrelli gave no details on the suspect's injury, but said in an emailed statement that it was not from a gunshot.
Another employee of the facility was treated at the scene for smoke inhalation. The flames were extinguished by 7 a.m., according to Ferrelli's email.
Online radar images showed a gaping hole in the nation's air traffic map over the upper Midwest.
At O'Hare's Terminal 3, long lines formed at ticket counters as airlines continued to check in passengers.
Waiting by an American Airlines counter, Jon Sciarrini said his homebound flight to Dallas had been delayed, and he didn't know whether he should wait or try to arrange another flight.
"It's pretty frustrating -- a little like being in purgatory," the IT specialist said.
It was the second time since May that a problem at one of the Chicago area's major control facilities prompted a ground stop at O'Hare and Midway international airports.
In May, an electrical problem forced the evacuation of a regional radar facility in suburban Elgin. A bathroom exhaust fan overheated and melted insulation on some wires, sending smoke through the facility's ventilation system and into the control room.
That site was evacuated for three hours, and more than 1,100 flights were canceled.
The Aurora facility, known as an enroute center, handles aircraft flying at high altitudes, including those approaching or leaving Chicago airports. Air traffic closer to the airports is handled by a different facility and by the control towers located at the airfields.
A computer glitch at a similar facility on the West Coast in April forced a 45-minute shutdown at Los Angeles International Airport.
MPR News reporter Jon Collins contributed to this report.