A large power outage leaves over 90,000 customers without power in San Francisco on April 21, 2017.
Media: jtucker@sfchronicle.com / sfchronicle.com
A massive power outage in San Francisco caused a blackout Friday morning in neighborhoods across the city, from the Financial District to the Presidio, forcing the closure of businesses, a BART station and a federal courthouse, officials said.
A spokesman for Pacific Gas and Electric Co. said at least 90,000 customers lost power and that there had been a fire at a substation on Larkin Street. It wasn’t immediately clear whether the fire caused the outage, which swept through the city after 9 a.m., or was ignited as a result of the outage.
The San Francisco Fire Department was responding to numerous calls for service, including people stuck in elevators, but reported no injuries as of 10 a.m. Everywhere, sirens blared as engines maneuvered along jammed streets.
  • Benjamin W. Feldman took this photo in the Montgomery BART Station during a power outage that hit large areas of San Francisco on April, 21, 2017. Photo: Courtesy Benjamin W. Feldman / Twitter @BWFeldman

Photo: Courtesy Benjamin W. Feldman / Twitter @BWFeldman
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Benjamin W. Feldman took this photo in the Montgomery BART Station during a power outage that hit large areas of San Francisco on April, 21, 2017.
Traffic lights were out in scores of intersections, and traffic was backing up on downtown streets as drivers grew frustrated and honked at each other.
BART’s Montgomery Station was closed due to the outage, and trains were running through the station without stopping. All cable cars were down, as were several Muni bus lines that typically run on electricity from overhead wires, including the 30, 45, 22, and 24. Shuttles were put in place to provide service, according to the Municipal Transportation Agency.
Muni trains, however, were still running both underground and above ground, though delays were expected due to the extensive problems with traffic lights. The subway stop at Montgomery Street was closed, with Muni trains — like BART trains — running through without stopping.
A number of schools in San Francisco were struck by the outage, including Spring Valley Science School, Sutro Elementary, Civic Center Secondary School, Alamo Elementary, Galileo Academy of Science and Technology and Cobb Elementary.

The Phillip Burton Federal Building and U.S. Courthouse at 450 Golden Gate Ave. was among the many buildings closed down by the outage.
A PG&E spokesman said the company was trying to determine the cause of the outage, as well as how long it would take to restore power.
Daisy Prado, a 23-year-old South Bay resident, said she was sitting at her desk on the 14th floor of an office building on the 200 block of Montgomery Street in the Financial District when the power suddenly dropped out. She looked out the window and saw the buildings across the street go dark.
“They told us on an intercom to just stay calm,” Prado said. “People are hanging out the side of their buildings waiting to see what’s going to happen.”
Prado said she left work, looking for a coffee shop with power and Wi-Fi, but hadn’t had any luck.
Aaron Trzesniewski was in a cable car near Sutter and Powell streets when the electricity cut out.
“It’s huge,” Trzesniewski said. “All the retailers are down, all the businesses, Starbucks, everybody.”
All around Union Square, the lights were out in the boutiques and restaurants, and rows of shuttered businesses extended into the Tenderloin and Chinatown. Workers stood outside, waiting, or in some cases they stood inside, with the doors closed.
A lot of people just milled about, drinking coffee or staring at their phones.
Check back for updates.