Three checkpoints were closed and officers reviewed security footage from all three exits.
The videotapes showed that no one entered the secure area through the exit while it was unguarded. /*TSA*/ authorities are reviewing how long the exit was left unattended.
Airport spokesman Marshal Lowe says all terminals are now open. He says five arrivals and three departures were slightly delayed.
Officials said the incident will be investigated.
The Associated Press contributed to this report.