The fiery blast occurred at a Yolo County property used by Devastating Pyrotechnics, a company known for staging large-scale fireworks displays.

People were urged to avoid the area after the blast, which set off a barrage of fireworks and caused a massive blaze.

Seven people are still "unaccounted for" in Yolo County's town of Esparto after several explosions at a fireworks warehouse resulted in a fire, officials said.