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Southern California Edison employees planned to “take an unprecedented step to inspect 300 vaults” Friday after a massive explosion that was caught on cellphone video caused some 30,000 customers to lose power just two weeks after a series of underground vault fires resulted in a three-day outage for some customers in the area.

About 260 customers remained without power Friday after a vault explosion Thursday afternoon near West 10th Street and Pine Avenue (map) impacted some 30,000 customers, officials said.

Cellphone video of the explosion showed smoke coming from the vault before it apparently blew up, sending flames into the air.

“We are going to take an unprecedented step to inspect 300 vaults today,” Edison’s Steve Conroy said Friday morning. “There’ll be two-man crews and they’re going to inspect those vaults to ensure they’re safe and that they can perform the way they’re supposed to, which is safe and reliably.”

Edison planned to deploy the crews around 10 a.m., and expected power to be fully restored by 6 p.m. as long as the crew did not find any additional problems.

Those still without power were mostly located near East Ninth street and Locust Avenue (map), the Long Beach Police Department stated around 6:30 a.m.

The Civic Center, including City Hall, the main library and Police Department headquarters were expected to remain open Friday, and employees “should report to work,” police stated.

Thursday’s explosion came two weeks after a series of underground vault fires in the downtown Long Beach area on July 15 left more than 4,800 customers without power.

In that incident, people were urged to stay indoors because falling debris from manhole covers that blew into the air caused a safety hazard. It took three days for power to be fully restored.

When asked if it was safe to walk around Long Beach on Friday, Conroy said “yes.”

“We believe that, yes, it is safe to walk around,” he replied. “We are glad and hopeful and happy that no one was injured, but right now our focus will be on inspecting those vaults and getting the lights on to those 260 customers.”

The cause of Thursday’s explosion was unknown, Conroy said.

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