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Los Angeles crews worked overnight and into Sunday to fully restore power to 94,000 customers left without electricity after an explosion at a Los Angeles Department of Water and Power plant in Northridge on Saturday night.

The high voltage explosion occurred around 6:53 p.m. at Receiving Station J in the 18900 block of Parthenia Street. Power was fully restored just before 9 a.m. Sunday to more than 144,000 customers originally affected by the fire and outage.

The 230 Kilovolt equipment, which carries high voltage electricity and distributes it to customers in the surrounding area, caught fire, according to a LADWP press release.

As much as 60,000 gallons of mineral oil was heavily involved with fire and was believed to be “fully energized,” officials said.

The fire only affected one portion of the station but power to and from the facility was shut off while LAFD personnel work to put the fire out, the Department added.

Residential and commercial customers in the areas of Northridge, Winnetka, Reseda, Lake Balboa, Tarzana, North Hills, Granada Hills, Chatsworth, West Hills, Canoga Park, and Woodland Hills were without power and the blackout extends for 15-square miles, according to the LADWP.

“Firefighters arrived on scene and found heavy black smoke and an active fire burning in the center of this complex,” said Asst. Chief Patrick Butler. “Currently our operation involves putting foam and cooling the area with water.”

Seventy-four firefighters battled the flames and extinguished the fire in two hours. No injuries were reported.

Parthenia Street was temporarily closed in both directions between Vanalden Avenue and Yolanda Avenue.

Crews began reenergizing affected areas after the fire was extinguished and restored power to nearly 50,000 residents by 10 p.m.

Sunday morning a hazardous material crew was on scene working on a clean up in an attempt to keep the oil from making its way into the L.A. River.

The cause of the fire was considered accidental, and utility officials attributed it to a mechanical malfunction.

KTLA’s Nisha Gutierrez-Jaime contributed to this story.