At least 30,000 Southern California Edison customers lost power Thursday after an underground vault explosion in downtown Long Beach.
No injuries resulted from the blast, which was reported about 4:15 p.m. in the area of 10th Street and Pine Avenue, Susan Cox of SCE said. Crews were at the scene making repairs, she said.
By 8 p.m., all but around 1,000 utility customers had their service restored, said Long Beach Mayor Robert Garcia said. By 11 p.m., 400 customers remained without power.
The Southern California Edison outage website showed 254 customers remained without power early Friday. Some customers weren't expected to have service restored until Friday, Cox had said earlier.
"Southern California Edison continues to work diligently on identifying the problem to restore services as soon as possible," SCE said in a news release. "There is no estimated time frame for restoration of services until Southern California Edison crews can conduct an adequate assessment."
Southern California Edison added they planned to send over 100 crews to the area to "conduct detailed inspections on more than 300 underground vaults," Friday morning.
City officials have activated the Emergency Operations Center. The Long Beach Community Emergency Response Team and Long Beach search and rescue program were also activated. Anticipating that the power outage may extend through the evening, city officials said they plan to open a shelter.
It's unclear what caused the blast, but Cox said the problem was similar to underground electrical vault fires that knocked out power to 4,800 customers on July 15.
In that case, service wasn't restored until July 19. No injuries were reported as a result of the fires, but some cast-iron manhole covers were deformed as they blasted into the air with explosive force and came down amid midday traffic in the city's downtown streets.
Residents were frustrated.
"That was the first thing on my mind ... 'Oh, no not again!'" said Vivek Chandru Padmanaban, a resident.
Paul Grigaux, of Southern California Edison, said it was unexpected.
"We don't expect it to happen again but it's too early to tell," he said.
The force of the explosion was so strong it tore the wall off an apartment building.
"A big boom!" said Venus Allen, a resident. "It just scared me."
Barbara Healy has medical issues.
"Oh no, not again," she said. "I forgot to refill all of my emergency supply of tanks of oxygen."
Long Beach Mayor Robert Garcia was frustrated.
"I'm very concerned," he said. "Clearly there's an issue with Edison's system and they just started their investigation for the last outage on what was going on."
City News Service contributed to this report.