The fire started shortly after 8 a.m. The escalator fire in the pedestrian tunnel between concourses B and C in Terminal 1 was caused by an electrical issue.
Sprinklers went off, and the tunnel was closed and electricity turned off. Power was restored around 9:30 a.m.
People are being shuttled around the tunnel, CFD said.
No injuries were reported.
The cause of the fire is under investigation.
Officials with United Airlines reported that some flights were delayed due to the incident, but regular operations had resumed by noon.
