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.

Rescue crews are searching for seven people still missing days after an explosion at a fireworks warehouse in Northern California shook a tiny farming community and forced the cancellation of nearby July Fourth celebrations.

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