All New York City-area and Philadelphia-area airports were briefly shut down by the Federal Aviation Administration on Saturday afternoon over concerns about their staff being infected with the coronavirus.

The shutdown was over an air traffic controller testing positive for coronavirus. The full suspension of flights lasted approximately one hour, but there have been some delays in getting operations at all of the airports back on track.

At 2:21 PM NY Center is beginning “a slow process” reopening. “This is a very fluid process, dynamically changing as ZNY is attempting to stabilize operations and re-staff positions,” according to A4A guidance to planners. — Jon Ostrower (@jonostrower) March 21, 2020

Jon Ostrower, the Editor in Chief of The Air Current tweeted that at 2:21p.m. New York Center was beginning a “slow process” of reopening.

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BREAKING: FAA stops all departures at ALL New York City area airports, Philadelphia, and others due to staffing issues related to Corona Virus. pic.twitter.com/mypwysnfww — Sam Sweeney (@SweeneyABC) March 21, 2020

Flight Radar tweeted a statement from the Federal Aviation Administration saying that an air traffic controller at New York Air Route Traffic Control Center in Ronkonkoma had tested positive for COVID-19 earlier in the day.

“The trainee has not been at the facility since March 17. We have contacted local health authorities and we are developing a plan to quickly sanitize/clean the affected areas. The center remains open and operational. The FAA has initiated traffic management initiatives for sectors closed during the sanitization process. Flights will be rerouted as part of a longstanding contingency plan to ensure continued operations,” the statement said.

Operations moving toward normal in New York ARTCC airspace, but delays are likely as controllers figure out how best to accommodate the traffic. 📡 https://t.co/1GI1i8HJ1h https://t.co/V4TyltKapi — Flightradar24 (@flightradar24) March 21, 2020

On Friday, the air traffic control tower at John F. Kennedy International Airport in New York City was temporarily closed for cleaning after a technician tested positive for the coronavirus.

The New York Daily News reports that the grounding was expected to be lifted by 3 p.m. although other temporary shut downs could happen in the future, officials said.