A pyrotechnics business in Northern California has confirmed that an unspecified number of its employees were "lost" when a warehouse full of fireworks exploded earlier this week, sparking a wildfire and days-long evacuation for nearby communities.

Seven people are missing after a warehouse holding fireworks caught fire and set off a series of massive explosions in Northern California late Tuesday.

The company indicated that multiple people died in the incident three days before the Fourth of July, but officials have not issued a determination.