A five-story structure fire at the Department of Water Resources Ronald B. Robie power plant in Oroville broke out early Thursday morning.
CAL FIRE said the fire was expected to last several days but was controlled by Friday afternoon.
Due to the collapse of power plant heavy equipment within the structure and life-threatening hazards within the power plant, fire crews were repositioned to the exterior.
Fire officials said the blaze started around 7:30 a.m. Thursday. The power plant is five stories in size, four stories below ground and one story above ground.
On Friday, fire crews made their way into the burning building to fight the fire and assess the damage. Two floors underground and one floor above ground have heavy smoke damage.
CAL FIRE along with other multiple fire agencies helped assist the fire. Crews will remain at the power plant until Saturday afternoon.
The cause of the fire is still under investigation.