After blasts injure five at Oktoberfest in Huntington Beach, many ask: What caused it?

Southern California Edison is still investigating what caused a transformer to explode Saturday night, tearing off a 50-pound door from an underground vault, and injuring five, including two firefighters.

from California https://www.latimes.com/california/story/2019-10-06/oktoberfest-huntington-beach-transformer-blast-injured
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