LOS ANGELES, July 2 (Xinhua) -- Seven people are unaccounted for after a series of explosions at a fireworks warehouse sparked a wildfire on Tuesday in Northern California, the United States, local authorities said Wednesday.

The explosions occurred at a facility in Yolo County, northwest of Sacramento, igniting the fire around 6 p.m. Tuesday local time (0100 GMT Wednesday) in the town of Esparto.

The fire was not contained as of Wednesday noon, according to an update of the California Department of Forestry and Fire Protection (Cal Fire).

Yolo County officials issued mandatory evacuation orders for a one-mile radius surrounding the site. The County Sheriff's Office advised residents to avoid the area for several days while investigations into the cause of the explosions continue.

As of late morning Wednesday, Cal Fire reported that seven individuals remained missing. Emergency personnel are actively working to determine their whereabouts.

The accident also caused power outages affecting nearly 2,200 customers of Pacific Gas and Electric in the surrounding area. ■