More than 40 flights were diverted from Sky Harbor International Airport after a fire alarm in the control tower was activated Sunday morning.
Airport officials say the air traffic control tower was evacuated as a precaution.
During the incident, more than 40 inbound aircraft were diverted to nearby airports including Tucson and Mesa Gateway, according to airport officials.
Phoenix fire said the issue in the control tower stemmed from a malfunction in an air handler that was off-gassing steam, which caused a sensor to set the alarms off.
— PHX Sky Harbor (@PHXSkyHarbor) September 24, 2017
Airport officials said tower employees are now returning.
Click here to check flight statuses at Sky Harbor.