John Kelly, a Port Authority of New York and New Jersey spokesman, said the camera at a security checkpoint was streaming live images but wasn't recording them.
That made it impossible for Transportation Security Administration personnel to check an image of a man seen walking in through an exit door Sunday evening until it could view tapes from a nearby Continental Airlines surveillance camera.
It was not known how long the camera at the TSA security checkpoint had stopped storing footage because archived images are only retrieved if an incident has occurred or is suspected, TSA spokeswoman Ann Davis said Tuesday. According to Davis, TSA will check the cameras' archiving daily.
The cameras were installed by the Port Authority about two years ago, and the agency maintains and operates them.
The incident shut down an entire terminal at the airport and stopped flights for six hours. The man, who has not been identified or located, leaving the terminal about 20 minutes after the security breach.