Fireworks blast victim's mom shocked by Grand Jury's scathing report: "Officials Knew, None Acted"

OAKLAND, Calif. - Stunning new details were laid out in the Yolo County Civil Grand Jury's report Thursday about the fireworks warehouse explosion that killed seven people in Esparto in Yolo County on July 1, 2025.

The report's scathing title "Officials Knew, None Acted," states that the County Building Services Department received a tip in June 2022, that the agricultural building in Esparto contained illegal fireworks for two pyrotechnic companies.

Conflicts of interest 

The report says building services officials went to inspect the site, but emails said they would "'tread lightly' as the property was owned by sheriff's deputies" including deputies they work with.

The report noted potential conflicts of interest involving Kenneth Chee, owner of Devastating Pyrotechnics, and the property owners, Tammy Machado, who worked in the Yolo County Sheriff's office legal department, and her husband Sam Machado, a lieutenant in the Sheriff's office. Tammy's sister, Rieko Matsumura, was also a deputy in Esparto, on disability leave prior to the explosion "retired from the department in September 2025."

The report said following the inspection, there were no enforcement actions or citations.

Knowledge of illegal fireworks

A chart in the report, highlights county groups "with knowledge of illegal fireworks businesses operating at the site."

Those include: the Sheriff Coroner Public Administrator, County Counsel, Community Services, Community Development Division, Hazardous Materials, Building Division, Inspections and Plan Review, Planning, and Code Enforcement departments.

Victims' families grieving

That came as a shock to families of the seven victims killed in the blast.

Lupe Mendoza-Melendez, the mother of Joel Melendez Jr., said her son was a father of two babies who would grow up never knowing her son. She choked up with tears as she spoke about the pain her family has endured since the blast, and was upset that county officials within the fire department, sheriff's office and other departments appear to have ignored the law.

"I didn't know it was going to be that deep, that many people could have prevented it. I didn't know that many people could have saved my son, saved me, because part of me died with him," Mendoza-Melendez said, in tears.

Attorney Kyle Tambornini is representing Maria Melendez, wife of Joel Jeremias Melendez, 28, of Sacramento. He also represents Maria Soriano, partner of Christopher Goltiao Bocog, 45, of San Francisco.

The other victims were identified as: 

• Angel Mathew Voller, 18, of Stockton
• Carlos Javier Rodriguez-Mora, 43, of San Andreas
• Neil Justin Li, 41, of San Francisco
• Jesus Manaces Ramos, 18, of San Pablo
• Jhony Ernesto Ramos, 22, of San Pablo

The victims' families filed a civil claim with the county board of supervisors, which was denied last month. They are now pursuing a civil lawsuit.

"I didn't know that many people had a chance to do something and didn't do nothing," Mendoza-Melendez said.

"They had this building being built," Tambornini said. "They chose to look the other way and could have prevented this from occurring by simply enforcing the rules that had been on the books since 2001."

The victims' attorneys say the report shows a problem with the county's culture of favoritism, and a tolerance for grave conflicts of interest.

"As we understand it, there was a fundraising event that was put on yearly. One of the owners was a volunteer firefighter for the fire district," Tambornini said.

Yolo County officials refused a request for an interview, and said they stood by what they said to the grand jury.

What's next:

The report recommended more than 30 changes to the county's policies.

It also said the district attorney is pursuing potential criminal charges.