Two people were hospitalized in critical condition after illegal fireworks being manufactured inside a home in Hayward exploded Thursday, authorities said.

California has seen a spate of accidental fireworks explosions leading up to the Fourth of July with a Thursday morning detonation killing 1 in a Simi Valley home and a similar incident critically injuring two people in a Bay Area residence.

Police and firefighters responded to reports of a large explosion followed by a series of smaller explosions on July 3.