Operations have returned to normal at Hartsfield-Jackson International Airport after two firefighters were slightly hurt fighting a predawn fire that sent smoke pouring into a concourse.

The smoke, which was detected around 5:20 a.m. near the train level of the “T” concourse, apparently came from an escalator motor, according to airport spokesman Reese McCranie.

“The incident was contained within 30 minutes, but it did have operational impacts in the beginning,” McCranie said.

“As of now, the trains are running and all gates are operational,” McCranie said just before 9 a.m.

Atlanta fire spokeswoman Janet Ward said the firefighters were hurt when they slipped in water.

“There was heavy smoke in the area and passengers were being re-routed to other concourses,” Ward told The Atlanta Journal-Constitution in an e-mail. She said the firefighters were not badly hurt, and did not need to be transported to the hospital.

The fire forced airport customer service personnel to re-route security lines, which snaked through the baggage claim area just before 8 a.m. The airport’s website was reporting security wait times of 30 to 40 minutes at all three domestic terminal checkpoints at 8 a.m.

McCranie said the incident led to longer-than-usual security waits on an already “busy travel day because of yesterday’s holiday.”

By 9 a.m., the wait times had dropped to less than 10 minutes at the main checkpoint and 10 to 20 minutes at other checkpoints. “All lanes are open and all security checkpoints are open,” McCranie said.

McCranie said one flight was delayed by the early-morning fire.

In February, the airport's people-mover system was shut down because of smoke in a tunnel. The smoke apparently came from an electric motor on a train car.

In June, an explosion in a maintenance shed outside Concourse D prompted the evacuation of the concourse.

No injuries were reported in either incident.