“This was not a deliberate act. The employee was just switching out a piece of equipment that was problematic.”-Daniel Froetscher, Arizona Public Service

At least 2.5 million people in the U.S. and Mexico, lost power because of maintenance at a Yuma, Arizona, substation.

Around 15:30 September 8, monitoring equipment was replaced.  That caused power to go out for about 56,000 customers.  Ten minutes later, after an attempt to restore power, the lights went out for 2.5 million customers from Yuma, Arizona, to San Diego, California, to Tijuana, Baja California.

Apparently circuits were shorted out.  Power company officials are trying to find out why such actions would have created a “cascade” effect along the power grid.

The power outage also shut down the San Onofre nuclear plant, and caused a 3.2-million gallon sewage spill San Diego beaches.