Power is being restored for tens of thousands of people in California's Bay Area.

FOX's Jessica Rosenthal reports:

More than 90,000 customers were without power for much of Friday morning. The fire department responded to a fire at a substation and they're investigating to see how that's connected to the outage.

At one point that about 20 people were stuck in elevators, but everyone was rescued.

The Bay Area Rapid Transit System said they were still able to operate, but they had to install generators at one station before using it again. The outage temporarily made it too dark for people exiting the trains there.

Jessica Rosenthal, FOX News.

Follow Jessica Rosenthal on Twitter: @JessicaFOXNews