Hundreds of people are without power, and seven people remain missing after a violent explosion at a fireworks facility in Yolo County, California, early Tuesday evening.

At least two people were injured in the explosion, which happened just before 6 p.m. local time at a facility housing commercial fireworks in Esparto.

During a news conference on Wednesday, Esparto Fire Chief Curtis Lawrence confirmed firefighters initially entered the building, but were later pulled out due to “the severity and the risks that were there.”

“Our agency, being here in the local in a small community, we are primarily volunteer agencies,” Lawrence said. “I would be remiss if I didn’t add that I’m really thankful and proud of all of our responders that stepped up yesterday, and even today, and came out here. … We appreciate all the responders and the mutual aid partners that came and assisted us.”

A large plume of smoke rose from a fireworks building in Yolo County, Calif., on Tuesday. (CAL Fire)

CAL FIRE confirmed the building was owned by an active pyrotechnic license holder, though the owner’s identity has not yet been released.

The Office of the State Fire Marshal, which is leading the investigation, sent an arson and bomb investigation team to the area, according to Gov. Gavin Newsom‘s office.

As of Wednesday afternoon, 78.3 acres had burned with 0% containment, according to CAL FIRE.

Officials have not yet released the cause of the fire.