OROVILLE, Calif. (AP) — A fire continues to burn at a Northern California plant that supplies electricity to pump water as part of a major water delivery system in the state.

California Department of Water Resources spokesman Ted Thomas says firefighters were pushed out of the Ronald B. Robie Thermalito Pumping-Generating plant near Oroville by collapsing equipment and poor visibility after responding to the fire Thursday morning. But they were planning on going back in on Friday.

The cause of the blaze remains under investigation.

Thomas said water deliveries will not be affected since water from nearby Lake Oroville — a major state reservoir — can be diverted around the damaged plant. The state, however, will have to purchase additional power to pump water.

The plant is part of the State Water Project, which supplies water to farmland and more than 25 million residents.

Copyright 2012 The Associated Press.