Firefighters across the state will be on alert due to high fire danger this lengthy holiday weekend.
In the Bay Area, some places have dry grass vulnerable to any fireworks.
"We're already getting reports of people lighting off illegal fireworks," Santa Clara Fire Department Battalion Chief Drew Miller said.
Fire departments are increasing staff through the Fourth of July. Cal Fire has every firefighter in the state on call as well.
In the East Bay, fireworks are illegal in every city in Contra Costa County, but the county's fire department activated its mobile command unit in preparation of having to respond to a large fire.
"People will take Monday off so the party starts here Friday night," Contra Costa County Fire Marshal Robert Marshall said.
In Alameda County, "safe and sane" fireworks are allowed in Newark, Union City and Dublin, but all other fireworks are illegal and will be seized by authorities.
More than 3,200 pounds of illegal fireworks were seized Friday in San Leandro. This week alone, more than 5,000 pounds of illegal fireworks have been apprehended from various spots in Alameda County.
The hope among fire officials is that seizing illegal fireworks will prevent potentially catastophic fires from breaking out.
On Thursday, firefighters responded to five small fires near Mount Hamilton in Santa Clara County. All five fires sparked around the same time Thursday and firefighters still do not have a cause.
A fire Thursday afternoon in San Jose near Penitencia Creek spread the department thin. But firefighters said they will be ready once fireworks light up the sky.