A fire broke out Wednesday morning at a United Airlines maintenance facility at San Francisco International Airport, forcing the building to be evacuated as a large plume of smoke soared into the air.

The fire, which began around 7:30 a.m., was apparently caused by a rooftop HVAC unit, said Doug Yakel, an airport spokesman. The blaze was extinguished by 8:21 a.m.

San Francisco firefighters responded to the maintenance facility, which is located on the north end of the airport, and safely evacuated people from the fifth floor.

United Airlines officials are reviewing the damage, which appears to be contained to the roof.

No flights or terminals were affected.

Ashley McBride is a San Francisco Chronicle staff writer. Email: [email protected] Twitter: @Ashleynmcb

———

©2019 the San Francisco Chronicle

Visit the San Francisco Chronicle at www.sfchronicle.com

Distributed by Tribune Content Agency, LLC.