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Almost two months after a power outage that left several million residents in the region in the dark, officials said at a public hearing Wednesday they still don’t know why the blackout occurred, reports the North County Times.

The head of the California Independent System Operator, which is one of the regulators for San Diego Gas & Electric Co., said they would have a report on it by early January, the paper reported.

Officials said the Sept. 8 outage was due to a series of events and not solely caused by one utility worker in Arizona as was first reported. Last month we reported that SDG&E never anticipated what happened during the blackout:

Because SDG&E never planned for it, (Jim Avery, SDG&E’s senior vice president of power supply) said, the safeguards to prevent a system-wide collapse didn’t work. San Diego has three substations where grid managers and utility officials can stop a surge from turning off local power plants, too. They closed none before the blackout. If they had, the whole system wouldn’t have failed.

Avery said the new conditions arrived too fast for humans to act and the computer sensors that could have automatically closed the gateways didn’t because the scenario had never been planned for.

The power outage also caused the spill of millions of gallons of sewage. Here’s a video explaining how that happened:

You can watch video of the whole hearing here. The panel on wastewater begins around the 2:32:30 mark.

Dagny Salas is the web editor at You can contact her directly at or 619.550.5669.

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Dagny Salas

Dagny Salas was web editor at Voice of San Diego from 2010 to 2013. She was an investigative fellow at VOSD from 2009 to 2010.

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