ABC News October 6, 2019

Series of explosions rock California Oktoberfest celebrations

WATCH: A transformer explodes at California Oktoberfest celebration

A series of explosions rocked an Oktoberfest celebration in Huntington Beach, California, injuring five people.

Authorities on Saturday responded to the scene at 8:10 p.m. local time to reports of multiple explosions that caused a transformer fire at the Old World Village complex. The complex had been hosting the Old World Village Oktoberfest festival.

Koray Kircaoglu via Reuters
Smoke and fire are seen following an explosion during California Oktoberfest celebration in Huntington Beach, Calif., Oct. 5, 2019, in this picture obtained from social media video.

Staff at a festival restaurant noticed an odor coming from an underground vault just outside the facility, Jeff Lopez of the Huntington Beach Fire Department told reporters Sunday. The underground vault contained three transformers but only one exploded. At one point the vault's 50-lb. metal lid flew off during the explosion, Lopez said.

Emily Rasmussen/The Orange County Register/SCNG via AP)
Emergency personnel respond to explosions where multiple people were injured at the Old World Village, Oct. 5, 2019, in Huntington Beach, Calif.

Two firefighters at the scene were injured and treated at a local burn center. Both have been released. A third person is still hospitalized with moderate to severe injuries, Lopez said. Damages to the restaurant were minimal.

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The area was immediately evacuated and a HAZMAT team was called on to investigate the explosions.

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Koray Kircaoglu via Reuters
Emergency services are seen following an explosion during California Oktoberfest celebration in Huntington Beach, Calif., Oct. 5, 2019, in this picture obtained from social media video.

Witness Kyle Nelson told a local television station that he heard and saw three large explosions in rapid succession coming from the festival, according to the AP.

ABC News' Matt Fuhrman contributed to this report.