Yolo County Officials Ignored Illegal Fireworks Site Before Deadly Blast
A civil grand jury report finds Yolo County officials knew about an illegal fireworks operation in Esparto for years before an explosion killed seven men.
Seven men died in a fireworks explosion last July that a civil grand jury says county officials could have stopped years before it happened.
The 32-page report, titled “Esparto Fireworks Explosion: Officials Knew, None Acted,” lands amid a criminal investigation by the Yolo County District Attorney’s Office and a separate Cal Fire inquiry. Its conclusions are blunt: multiple elected officials and law enforcement personnel knew about an illegal fireworks storage operation in the small Sacramento Valley town of Esparto, and nobody did anything about it.
“Inexplicably, no code enforcement occurred, even though all dangerous fireworks had been banned by ordinance throughout rural Yolo County since 2001,” the report states. “In the absence of official oversight and enforcement, unmitigated expansion of the fireworks businesses operating at the site in Esparto led directly to death and destruction from the Esparto Fireworks Explosion.”
The facility belonged to a company called Devastating Pyrotechnics, a name that reads differently after July 1, 2025. The business grew out of a hobby. Jerry Matsumura, a longtime Esparto farmer and local figure in a town of about 3,500 people, had for decades staged informal fireworks displays from his property. The spring show tested new products from his sideline operation selling professional-grade fireworks to local municipalities. The fall show burned off whatever inventory remained after summer sales. Residents knew about it. Apparently, so did county officials.
After Matsumura died in 2015, the business transferred to his partner Kenneth Chee, identified as a San Francisco resident. The property went to Matsumura’s daughters, Rieko Matsumura and Tammy Machado, along with Tammy’s husband Sam Machado. All three were employed by the Yolo County Sheriff’s Office at the time of the explosion. Rieko Matsumura has since retired from the department.
That employment connection sits at the heart of what the grand jury describes as potential conflicts of interest and “blind eye” policies. The report points to a June 2022 tip given to a county Building Services department official as one example of a moment when enforcement could have happened and didn’t.
The explosion killed seven men. Their families have filed wrongful death suits against the county, and the grand jury’s findings are likely to strengthen those cases considerably. When a report with a title this direct concludes that government officials knew about a code violation for more than two decades and chose not to act, it becomes difficult for the county to argue it had no knowledge of the risk.
What happened in Esparto fits a pattern that shows up in communities across California, where informal arrangements, personal relationships, and local familiarity create an atmosphere where rules bend for some people and not others. A fireworks ban on the books since 2001 apparently meant nothing when the people sitting on the land had family working for the Sheriff’s Office. That is not a system malfunction. That is the system working as designed for the people with the right connections.
The criminal investigation by the DA’s office is still active, which means charges against individuals could follow. Cal Fire’s separate probe adds another layer of potential liability. But the civil suits from victim families may ultimately produce more accountability than any criminal proceeding. Wrongful death litigation has discovery. It has depositions. It forces officials to answer questions under oath about what they knew and when they knew it.
Esparto is not a tech story. But the dynamics here, who gets oversight and who gets looked past, cut across every beat. Yolo County is close enough to Sacramento and the Bay Area that its governance failures ripple outward. And for seven families now living with the consequences of decisions officials made and didn’t make over more than two decades, the proximity of institutions that failed them is not an abstraction.
The grand jury report is a public document. The county will be required to respond to its findings. That response, when it comes, will be worth reading closely.