SAN FRANCISCO—A fire broke out at a maintenance building at San Francisco International Airport, which lead to evacuations on Wednesday, July 31. ABC 7 San Francisco first reported that the fire transpired around 7:30 a.m.

The San Francisco Fire Department tweeted “2nd ALARM FIRE AT @flySFO SFO UNITED MAINTENANCE OPERATIONS CENTER UNK INJURIES AT THIS TIME – BUILDING BEING EVACUATED-THIS IS NOT AT A TERMINAL AND AIRPORT IS OPEN MEDIA CONTACT DOUG.YAKEL@FLYSFO.COM.”

Fire officials tweeted the cause of the fire was a heating and air conditioning unit on the top of the building. 

Photo of smoke at SFO building.

Passengers at the airport posted photos via Twitter of what they saw, showing how much smoke was coming from the building.

At 8:20 a.m., the SFFD indicated via social media that there were no injuries from the fire or evacuation. Workers were allowed to return to the building and flights were not impacted by the fire. All operations at the airport have returned to their regular schedule.