A blaze broke out at an United Airlines maintenance facility at San Francisco International Airport Wednesday morning, according to officials.
No one was hurt, and flights were not impacted, officials said.
The San Francisco Fire Department said the two-alarm blaze burned on the fifth floor of the facility, which is located north of the terminals.
The terminals were not affected, SFO spokesman Doug Yakel said.
Preliminary information indicates that the blaze may have been caused by a heating, ventilation and air conditioning unit on the roof, according to the fire department.
Further information was not immediately available.