SAN FRANCISCO (CBS SF) – A power substation fire triggered a massive outage in San Francisco Friday, forcing the closure of a downtown BART station during rush hour and leaving some customers without power until it was finally restored after 5 p.m.

The outage left people stuck in elevators, shut down hospital operating rooms and halted service on city’s famed cable car lines.

Pacific Gas and Electric spokesman Barry Anderson said the power outage began with the failure of a circuit breaker at the large substation at Larkin and Eddy streets.

“We had equipment failure, the catastrophic failure of a circuit breaker,” said Anderson. “When it failed, it created a fire in the insulation surrounding the breaker … Something went wrong with the breaker to cause it to explode.”

A city transportation official said that at its height, the outage knocked out a third of San Francisco’s traffic signals.

Mayor Ed Lee said of the 88,000 customers who lost power, 58,000 has been restored by 2 p.m. The remainder would be restored by 5 p.m.

21 schools were among the customers who lost power. At its worst, approximately 300 or about one quarter of the city’s stoplights were out.

PG&E said the equipment was old. From a PR standpoint, the meltdown couldn’t have had worse timing.

Just a few days ago, reports revealed that PG&E had given all its executives substantial raises. With customers paying higher rates, some are understandably concerned the utility is spending the money in the wrong place.

“The Larkin substation was one we identified to be redone in 2017-18 and needed to be modernized,” said PG&E spokesperson Barry Anderson.

What was likely going to be a $100 million job for that substation alone now could cost much more.

As of 4 p.m., the number of customers who still did not have power had been reduced to less than 3,000. Power was restored to all customers shortly after 5 p.m.

Lee said there were no reports of major injuries during the outage.

The city’s Department of Emergency Management said the outages were concentrated in the northern part of San Francisco. The fire department responded to at least 20 reports of people stuck in downtown elevators.

During the height of the outage, California Pacific Medical Center forced to go on backup power and shut down its operating rooms.

The outage began 9:15 a.m., Anderson said. Almost immediately BART sent out an alert advising passengers of the closure at Montgomery St. Station “due to a technical problem with PG&E.” Commuters were told to take buses to their destinations in the downtown area.

The transit agency brought in a generator and parked it outside the station in an effort to get it back online. The generator was able to bring the station online at 11:32 a.m.

The Montgomery station is a key stop all BART lines coming into the city. San Francisco Muni underground lines and cable car lines were also knocked out of service.

The San Francisco Office of Emergency offices in the Fillmore District was knocked offline by the outage, officials said.

Meanwhile, the power outage caused traffic chaos on the streets of San Francisco.

SF #poweroutage seems to start around Grant & Market. Traffic free-for-all, but not too chaotic. @CBSSF pic.twitter.com/X1isQKkCtu — Wilson Walker (@Wilson_Walker) April 21, 2017

Mon Alicia took to Twitter to comment: “I always thought The Big One would throw San Francisco into mass chaos. I’m learning a large scale downtown power outage does the same.”

I always thought The Big One would throw San Francisco into mass chaos. I'm learning a large scale downtown power outage does the same. — Mon Alicia (@ohgeezthatone) April 21, 2017

Brandon Bradford tweeted: “Huge power outages in NYC and SF right now. In a movie people would be freaking out.”

Power was also out from San Francisco’s Union Square to the Marina District. Union Square shops were closed because of the outage. Power was also out at the Presidio.

#poweroutage no shops open in Union Sq. No street lights. Avoid area pic.twitter.com/dF2iAy9Paw — Louisa Pickering (@loulousfo) April 21, 2017

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