Fire officials are trying to determine if a firework thrown from Highway 580 set off a blaze at that burned part of a home in Castro Valley on Friday.
Someone reported sounds of an explosion and then reportedly saw smoke, according to officials.
Crews responded to a residence at 2234 Lobert Street and found a fire in the backyard of the home. A portion of the back of the house was partially burned.
There have been no reported injuries.
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