SAN FRANCISCO INT’L AIRPORT (CBS SF) – A fire that broke out at a maintenance facility at San Francisco International Airport on Wednesday morning has been contained.

According to San Francisco fire officials, the fire started burning at the United Airlines facility located north of the terminals shortly after 7:30 a.m. A second alarm has been called and the facility has been evacuated.

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Airport officials told KPIX 5 that the fire had originated from a rooftop HVAC unit at the facility.

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As of 8:20 a.m., the fire had been contained. No injuries were immediately reported and evacuated workers have since been allowed to return.

Multiple people on social media posted pictures of smoke coming from the area, which was visible for miles.

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Flights at SFO were not impacted during the fire and the airport remains open Wednesday.