SAN FRANCISCO (KRON) -- A grand jury released a scathing report detailing what led up to an explosion that killed seven workers "instantly" inside a warehouse in Yolo County. Many of the victims were San Francisco Bay Area residents, including the youngest victim, Jesus Manaces Ramos, 18, of San P ablo, who was working his first day on the job. On the evening of July 1, 2025, massive explosions and fires obliterated the property in Esparto, Calif. Officials with Cal Fire named the incident the "Oakdale Fire." The blast site was used by two fireworks companies, San Francisco-based Devastating Pyrotechnics and Blackstar Fireworks, for storing and manufacturing explosives, "even though all dangerous fireworks had been banned by ordinance throughout rural Yolo County since 2001," the grand jury found. Jesus Manaces Ramos, right, and his brother, Jhony Ernesto Ramos, left, were killed in the Yolo County fireworks warehouse explosion. (Photos courtesy GoFundMe) A Yolo County Sheriff's Office lieutenant, Sam Machado, and his wife, who also worked for the sheriff's office, owned the property and lived there, the report released Thursday states. They allegedly allowed the agricultural-zoned land to shift from a family farm with homes to a commercial explosives facility. The civil grand jury's investigation found, "Various top Yolo County officials were aware of illegal fireworks operations at the site for at least three years prior to the incident. Inexplicably, no code enforcement occurred. 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." "A massive explosion of dangerous stockpiled fireworks shook the surrounding community and damaged nearby properties. It was felt or heard by residents in Winters, Woodland and Davis, approximately 20 miles away. Seven employees of a company called Devastating Pyrotechnics were killed instantly," the report states. An investigation by the State Fire Marshal cited "illegal activities" as a root cause of the explosions. Lt. Machado's wife, Tammy Machado, worked in the county sheriff's legal department, and her sister was a deputy, according to the grand jury. "Over the years, Kenneth Chee, owner of Devastating Pyrotechnics ... expanded his use on the property owned and occupied by Sam Machado and Tammy Machado. Additional containers to hold explosives gradually appeared on the Machado property. Devastating Pyrotechnics obtained permits from State and Federal agencies to operate, although no local use permit or business license was ever obtained," the report states. When the landowners applied with the county for a permit to build a new 4,500-square-foot building, they said its purpose was to stole almonds harvested from a nearby orchard. Smoke and flames rise from a fireworks warehouse explosion, July 1, 2025, in Esparto, Calif. (Hudson Sheats via AP) Craig Cutright, the producer of shows for Devastating Pyrotechnics and resident on the Machado property, contacted county officials to see if he could establish a new fireworks business, the report states. The grand jury did not find any evidence that county officials advised Cutright that fireworks businesses were illegal in the area. "Later, he started his own business, Blackstar Fireworks, which also operated on the Machado property. Throughout this process, he was working as a volunteer firefighter with the Esparto Fire District," the report writes. In the summer of 2022, a Yolo County Building Services Department official reported receiving a tip that the property was being used by the two pyrotechnics businesses. "County Building Services Department officials, in a series of emails, said they were going out to the site to conduct an inspection, noting that they would 'tread lightly' as the property was owned by sheriff’s deputies," grand jurors discovered. Building officials later found that there were, in fact, pyrotechnic businesses operating at the site, even though they had been told it would be used for agricultural purposes. "Within days, this conversation about the site -- at least in email records provided by the County -- abruptly ceased. The department failed to take any action, and the fireworks business continued to quietly operate and even expand. The Grand Jury interviewed numerous County officials, but no one could recall any further conversations or meetings about the site," the report states. Grand Jury Esparto Fireworks ExplosionDownload Grand jurors titled their investigation report, "Esparto Fireworks Explosion: Officials Knew, None Acted." The report states that county employees may have been reluctant to "antagonize some sheriff’s officials," and decided against initiating any enforcement action on a property owned by sheriff’s department employees. The Oakdale Fire burned for six days before investigators could enter the charred disaster zone and recover the seven victims’ bodies. A coroner determined that the workers, including a trio of brothers, died from "multiple blast and thermal injuries." A coroner identified the workers killed as: Neil Justin Li, 41, of San Francisco Christopher Goltiao Bocog, 45, of San Francisco Jesus Manaces Ramos, 18, of San Pablo Jhony Ernesto Ramos, 22, of San Pablo Angel Mathew Voller, 18, of Stockton Carlos Javier Rodriguez-Mora, 43, of San Andreas Joel Jeremias Melendez, 28, of Sacramento In response to the grand jury's report, Yolo County officials wrote in a statement, "Yolo County recognizes that this incident had a profound impact on the Esparto community. The County extends its deepest condolences to the families and loved ones of the seven individuals that lost their lives. The Board of Supervisors understands why residents are seeking answers and is committed to the safety of our community, to fully understanding what occurred, and to ensuring accountability moving forward." The county's statement continued, "The Board of Supervisors respectfully disagrees with the report’s suggestion that the County does not take code enforcement seriously. While funding levels have varied historically, the Board has consistently supported and funded the County’s code enforcement program in recent -- compared to previous -- years and continues to recognize the essential role it plays in protecting community health and safety." CAL/OSHA issued 15 citations to Devastating Pyrotechnics. ...read more read less