A transformer reportedly exploded at a Southern California Oktoberfest celebration on Saturday night, resulting in injuries to two firefighters and two civilians, according to reports.

A fireball could be seen ballooning near the Old World Village restaurant in Huntington Beach around 8 p.m.

Witnesses reported hearing at least three explosions, according to The Los Angeles Times.

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The restaurant was evacuated.

The Huntington Beach Fire Department said all of the injuries were minor.

Officials said an underground electrical vault exploded, but they were still investigating the cause.

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Hundreds of customers were left without power after the explosion, The Times reported.

Huntington Beach is about 37 miles south of Los Angeles.