When a series of electrical explosions rattled an Oktoberfest celebration in Huntington Beach Saturday night, it sent some people screaming and running through the streets, witnesses say. The explosions came quickly, one after the other. Some witnesses described power outages as the first fireball shot up over the crowded Old World Village’s Oktoberfest celebration on Center Drive. Authorities initially said four people suffered minor injuries in the incident, but later said five people were hurt, including an unidentified civilian who suffered moderate to severe injuries, according to Huntington Beach Fire Department Battalion Chief Jeff Lopez. Firefighters were called to Old World German Restaurant shortly after 8 p.m. to respond to a transformer fire. As an employee led them to the transformers in the vault room, an explosion suddenly erupted, knocking the employee and firefighters down, according to Lopez. Two firefighters were injured and taken to a local burn center for treatment and later released, officials said. As firefighters got up, they noticed the employee that led them in was missing, Lopez said. They were searching for the person when another explosion followed about a minute later. The employee’s condition is unclear. A preliminary investigation found that one of the restaurant’s three transformers exploded in an underground vault, authorities said. The chief described the fire that resulted from the explosions as minimal, and said crews were able to extinguish the flames quickly. Hundreds of people are believed to have been at the event at the time. The chief described a “dazed” crowd standing outside as crews were trying to manuever through to get to the fire. Witness Kyle Nelson said he saw three large explosions in rapid succession coming from the festival Saturday. Another witness said she was standing in line waiting to get in to one of the venues when she saw “a ball of flame that came up,” followed by two more. “Every one just panicked and just started running every which way,” Glenis Peters said. “It was just chaos.” She described her friend grabbing her hand, and the two running away together, fearing everything would go up in flames. “It was really scary, you can feel the heat from it,” Peters said. “It was a huge ball of flame.” One employee working at the event told KTLA she smelled what she thought was gas shortly before the blasts. On Sunday morning, crews could be seen outside the restaurant, working around what appeared to be an electrical transformer. SoCal Edison is expected to continue the investigation to determine what went wrong with the transformer, Lopez said. The blasts knocked out power for at least 300 customers in the area, but it was expected to be restored at around noon, authorities said.