UPDATE: Georgia Power said late Sunday that they believe that a piece of switchgear in an underground electrical facility failed and started a fire.


What caused the power to go out at the world's busiest airport on Sunday? That's the question on the minds of people across the world after the outage that grounded planes and halted incoming traffic at Hartsfield-Jackson Atlanta International Airport.

So far, we don't have many answers.

The outage, which was initially reported just after noon, was the subject of much speculation. Rumors spread on social media that a construction crew cut a line. The airport said that had not been confirmed.

Georgia Power believes that the issue may have involved a fire which caused extensive damage in an underground electrical facility.

"The fire was safely extinguished by fire crews before we could enter the area to assess damage and begin repairs," the company said. "The event impacted not only the underground facilities, but also substations serving the Airport and, while the cause is not yet known, Georgia Power’s system responded by isolating areas where equipment wasn’t operating correctly to ensure safety and minimize damage."

By 8 p.m., power had been restored to Concourse F (the international terminal).

The company said it hoped to have power restored to the entire facility by midnight.

RELATED: Atlanta's airport goes dark: Videos from inside the terminal

AND: Atlanta airport blackout plays out on social media