Travellers at the busiest airport in the US were met with more than delays after foul-smelling brown water burst from the terminal’s ceiling, sending people scrambling for cover.

Passengers waiting to board their flights on Monday afternoon filmed as the water gushed from above, catching many by surprise.

The unpleasant incident prompted a wave of nose pinching as people realised the brown liquid appeared to be sewage.

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Footage taken by Jamaal Carlos Jr. shows liquid erupting through a ceiling panel at Hartsfield-Jackson Atlanta International Airport, splashing onto the terminal floor and prompting some passengers to cover their faces in disgust.

Mr Carlos, who was waiting to board a delayed flight to Dallas, said the smell was overwhelming.

“As we’re waiting, we see water just pouring from the ceiling. It had been pouring consistently for maybe 10 to 15 seconds,” the Daily Mail reported.

“And it just progressively got worse. The ceiling fell through and it stinks so bad.”

He claimed it took five to ten minutes for crews to respond and rope off the area with caution tape.

In the meantime, some passengers were left walking through the mess.

“Even after it poured... I thought they would get buckets or do something, but people were walking through it,” Mr Carlos said.

Airport officials eventually shut down the lower north checkpoint and rerouted passengers.

“It’s crazy,” he said.

“So they moved our gate... we were just so close to it, so they moved us a little bit further, but you could still smell it two or three gates down.”

Officials have not confirmed whether the fluid was sewage, but said they are investigating the cause of the leak.

“The affected area has been contained and remediation crews are actively working to clean and sanitise the space,” a spokesperson told 11 Alive.

Customer service representatives were deployed to redirect passengers, and emergency medical teams were sent in as a precaution.

“There is no impact to overall airport operations,” the airport said in a statement.