CONCORD, Calif. - The fireworks canister began crackling after ending up on a roof.
"Just a small firework that lands in someone's gutter," said Lon Goetsch, assistant chief of training at the Contra Cotsa County Fire Protection District.
But within a few minutes, that little canister caused a big fire.
"That's all it takes, is that small firework and that small amount of fire can extend into your home and it can quickly escalate into a structure fire," Goetsch said.
Thankfully, the blaze was just a demonstration, a stark reminder of how dangerous fireworks can be.
But a devastating fire on Memorial Day in Antioch was no simulation. A man threw fireworks into a field, which nearly destroyed two apartment buildings, authorities said.
"Up to 30 residents lost their homes, lost their apartments as a result of this one act of use of illegal fireworks," said Fire Chief Lewis Broschard.
James Sossaman, a convicted felon was arrested and charged with arson.
Contra Costa County District Attorney Diana Becton said the Board of Supervisors passed a new ordinance this week.
"Property owners can now be held accountable if illegal fireworks are used on their property," Becton said.
Sheriff's deputies can issue tickets that come with fines.
"They start at $100 and they can increase from there depending on the number of incidences."
In Richmond, the city is offering a $2,500 reward for every report that leads to an arrest or a fine for illegal fireworks.
Law enforcement has already made sizable fireworks busts, with seizures reported by Oakland, Menlo Park, East Palo Alto and South San Francisco police.
Authorities are girding for more "kabooms" this year, if last July Fourth was any indication.
"There was an unprecedented level of use of almost commercial-grade fireworks," Broschard said.
And with the specter of losing limbs and agitating pets and those with PTSD, fire officials say it's just not worth it.
"It happens. It's real. These fireworks are dangerous and they should not be used, period," Broschard said.
Residents are encouraged to sign up for the Contra Costa County Community Warning System to get emergency alerts online.