Residents of San Diego can turn their lights back on. The San Diego Gas and Electric Company says it has restored power to all 1.4 million customers in its service area after a utility worker set off a massive electrical failure while doing maintenance work near Yuma, Ariz. The accident knocked out power for almost five million people. Offices closed, but workers were stuck in gridlock because traffic lights went out. Sewage pumps failed, sending waste into the San Diego Bay. People were stuck in elevators and on rides at Sea World and Legoland. APS, Arizona's largest electric utility, says it is investigating why the accident cascaded across the power grid instead of remaining isolated in the Yuma area.