A grass fire damaged about 10 homes and consumed about 10 acres in Vallejo Monday night.
The blaze started at around 9 a.m. in the open space between Swanzy Court and Novone Street, prompting evacuation orders in the area, firefighters said.
Witnesses said wind was blowing hard and the cause was "definitely fireworks."
“We heard what sounded like gunshots and then we heard the sparkling so we knew that it was fireworks coming from down that way and we were wondering ourselves 'this is the craziest thing to do in a dry season,'" said said Jean Smotkin of Vallejo. "So fireworks were going off for maybe not even 10 minutes and then we heard the fire trucks and then when I look down there there was a blazing fire."
Engines as far away as Vacaville reported to the scene and warned about the dangers of fireworks.
"Officers are heading down now to try to figure out what the initial address was as well as a fire investigator coming in to determine who the suspects were,” said Vallejo Battalion Chief Cliff Campbell.
He added that it is ironic that a fire started in such a cool day, but shows how dry the grass is and urges people not to play with fireworks.
Evacuation orders were lifted around 10:30 p.m.
No additional information was immediately available.