Air traffic controllers lost contact with planes flying in and out of New Jersey’s Newark Liberty International Airport last week for around 90 seconds, Bloomberg reported Monday, providing critical insight into what has become a second week of delays at one of the nation’s busiest hubs for air travel.

The New York Times confirmed with the National Air Traffic Controllers Association that the outage affecting radar and communications occurred April 28. The disruption meant that air traffic controllers in Philadelphia who supervise Newark planes were “unable to see, hear or talk to” the aircraft for which they are responsible, the two outlets reported.

In the immediate aftermath of the incident, Newark saw hundreds of delays and cancellations that have continued to affect travelers at the airport this week.

United Airlines cited nonspecific technology failures on Friday when its CEO, Scott Kirby, issued a statement announcing the company would be canceling 35 daily flights out of Newark, which is a hub for the airline. Kirby said the technology problems were “compounded as over 20% of the FAA controllers for EWR” — the three-letter code for Newark — “walked off the job.”

But NATCA, the air traffic controllers’ union, pushed back on the suggestion that its members abruptly chose to abandon their posts.

It was the stress of losing all communications and radar that pushed some employees over the edge into needing time to recover from what is already a high-stress job, NATCA spokesman Galen Munroe told The New York Times.

Bloomberg also reported that the outage left a few controllers “visibly shaken” as some teared up and at least one experienced “stress-induced heart palpitations.”

The Federal Aviation Administration confirmed to HuffPost that “some controllers at the Philadelphia TRACON who work Newark arrivals and departures have taken time off to recover from the stress of multiple recent outages.”

“While we cannot quickly replace them due to this highly specialized profession, we continue to train controllers who will eventually be assigned to this busy airspace,” the agency continued.

“When staffing or equipment issues occur, the FAA will ensure safety by slowing the rate of arrivals into the airport.”

Details of the incident follow an eyebrow-raising report from NBC News correspondent Tom Costello, who said on MSNBC that an air traffic controller had explicitly told him Newark airport was not safe.

“Really an incredible statement, unsolicited,” Costello recounted on Friday. “He just said that to me, and separately: ‘Don’t fly into Newark. Avoid Newark at all costs.’”

HuffPost did not receive an immediate response from NATCA on Monday.

The FAA moved Newark’s air traffic control operation to Philadelphia last year to address staffing shortages.

For years, federal aviation officials and industry experts have been in agreement that the nation’s air traffic control systems are in dire need of upgrade — both in terms of computer power and people power.

“The technology that we are using is old. That’s what is causing the outages and delays we are seeing at Newark,” Transportation Secretary Sean Duffy said Friday.

“We use floppy discs,” he went on. “We use copper wires.”

Persistent nationwide staffing shortages have also put the U.S. approximately 3,000 air traffic controllers short of ideal levels.

Duffy promised to unveil a plan for a new “state-of-the-art, gold-plated” air traffic control system this week.