This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

CHICAGO — The air traffic control tower at Midway International Airport remains closed Wednesday after three technicians tested positive for COVID-19.

As of 9 a.m., at least 297 flights were reported to be canceled. Midway officials are asking travelers to call ahead and check in with your airline before coming to the airport.

The FAA said the airport remains open and operations will continue at a reduced rate until the situation is resolved.

Multiple backups are reportedly in place to support the air traffic system.

“The safety of our staff and the traveling public is the FAA’s top priority. Our controllers, inspectors and others with critical safety or security sensitive roles are essential components of our national airspace,” the FAA said.

Tuesday evening, Midway tweeted that flight operations will shift to “one-in-one-out.” A ground delay program has also been implemented by the FAA.