SAN DIEGO (AP) - Regulators have told six utilities and grid operators that they violated reliability standards during a 2011 blackout that left millions without power in Southern California and Mexico.
The preliminary findings by Federal Energy Regulatory Commission staff could lead to penalties or requirements to upgrade systems.
The Imperial Irrigation District says it is in settlement talks that would result in $9 million for upgrades and $3 million in penalties.
The California Independent System Operator, which operates the state power grid, says it doesn't believe it violated any reliability standards.
Others cited are Arizona Public Service; Southern California Edison; the Western Electricity Coordinating Council; and the Western Area Power Administration.
A maintenance procedure at a switching station near Yuma, Ariz., caused the blackout, which lasted up to 12 hours in some areas.
Copyright 2014 The Associated Press.