Several cases of illegal fireworks were found in the garage of the home on Los Positos Drive. At least one spent rocket was found on the roof, and several other used, illegal fireworks were found in the yard, said Battalion Chief Scott Brown.
Neighbors were also being questioned, but no suspect has been identified, Brown said.
When firefighters arrived at the house after the 5:44 p.m. call, they found heavy smoke and fire coming from the wood shake roof of the two-story residence, where two adults and three children live.
The Milpitas Fire Department said people inside the home were not aware of the fire until a neighbor told them their roof was ablaze. They got out of the house on their own and without injury. When firefighters went inside, they learned that the whole attic was on fire, too.
The home sustained an estimated $400,000 in damage.
Twenty-two firefighters and four engine companies got the blaze under control in about 50 minutes, with mutual aid provided by the Fremont Fire Department.
