Displays of illegal fireworks sparked small blazes on July 4 from Oakland to Vallejo.
No one was seriously injured in the blazes, although some charred grass was discovered near a home on Redwood Road in the Oakland Hills. Neighbors said people were setting off fireworks illegally about midnight.
Another grassfire started in Vallejo from illegal fireworks about 9:30 p.m.
KTVU's Rob Malcom contributed to this report.