The Benicia Bridge, By Laura López González & Monica Vaughan, April  18, 2026

Valero delayed reporting the March 26 flare-tower “material release,” which remains under investigation by several agencies. The plant may not have reported the flaring to state authorities at all, had it not been for Solano County officials’ urging.

A distinctive black plume from one of Valero’s three flare stacks made local headlines in March. Unsure of what was being spilled into the air, Benicia Fire Chief Josh Chadwick issued a voluntary shelter-in-place warning for the city, as previously reported by The Benicia Bridge. NBC News reported that about two dozen Valero workers were sent to the hospital with chemical burns caused by cleaning chemicals involved in the incident. Company officials denied that happened.

Earlier this week, General Manager Lauren Bird said the black plume was a composition of steam and rust. Bird was speaking April 14 at the final meeting of the refinery’s community advisory panel.

And although Bird said that about a dozen contractors were given first aid onsite, he says no one was taken to hospitals. He and other Valero officials faced tough questions from the refinery’s community advisory panel about why the company waited a day to report the incident to state monitors. Valero reported the flare to the California Office of Emergency Services, but only after calls from Solano County environmental health officers.

Valero said emission was non-toxic

March’s incident, Bird said, occurred after crews, using a mixture of steam and industrial cleaner to clear pipes, released too much steam into the system, blowing a seal and sending water and rust into the air via the plume.

“There were some odors associated with it, likely from the corrosion products that are being cleaned out of the system,” said Bird, who added the release went on for about six minutes before it was brought under control. “We pulled a sample of the material. The actual constituent analysis indicates the material was non-hazardous, it was not an irritant, it was non-toxic… it was not a carcinogenic.”

Valero sampled 14 sites in Benicia for possible contamination.

Bird said that workers nearby who were sprayed with the mixture accessed emergency safety showers before accessing first aid.

Solano County officials urged Valero to report the incident

California regulations require companies to immediately report any significant release or threatened release of a hazardous material to the California Office of Emergency Services.

State public records show Valero had an open hazardous materials spill report February and March related to ongoing flaring and sulfur dioxide releases. On March 26, Valero informed state officials of “no additional release.” A March 27 note says, “For yesterdays update report …the correct update is that there was a release of water with residual cleaning material and residual iron sulfide, at an unknown quantity.”

Refinery community advisory panel member Cara Bateman is an environmental manager. During the meeting Tuesday, she questioned why Valero did not report the event to the state that day.

Bird responded that the plant chose not to report initially because they knew the substance was non-toxic.

“Initially, even as of that evening, it hadn’t been reported to the state,” Bateman said. “You go through the [Office of Emergency Services’] database, and there are scores of reports every year from us because it caused some sort of public nuisance.”

She continued: “You had kids who got picked up from school to go home and people with crap on their cars.”

Solano County Supervising Hazardous Materials Specialist Chris Ambrose interrupted discussions to say that his team called Valero to urge the plant to report the emissions.

“Given that there were odors and potential off-site consequences, the next day, we got on the phone with [Valero] and asked, ‘Why wasn’t this reported?’ Ambrose told Tuesday’s community advisory meeting. “I’m not sure what discussions took place off the phone… [but Valero] called into the state.”

Although Bird apologized for the emission, he reiterated that the plant had conducted sampling and downwind monitoring, which showed the release was non-toxic.

Valero, others under investigation

Several agencies are investigating the incident for potential illegal actions.

Cal/OSHA received complaints from workers about the incident and launched an investigation into potential worker safety violations. Valero and contracting companies are named in the investigation, including Refined Technologies, USA Debusk, T.R.S.C., and Specialty Welding and Turnarounds. The investigation is ongoing.

In addition, the Bay Area Air District is investigating and has already issued a notice of violation that states the March 26 incident was a “public nuisance caused by emissions.”

The March incident marked the eighth public notification issued by the City of Benicia regarding public impacts from refinery shutdown operations.

The plant has officially stopped refining, meaning that flaring is over, Bird said. Valero plans to continue importing, storing, and distributing gas and diesel at the location before likely exiting within the next two years.

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Reposted with permision, The Benicia Bridge
Excellent reporting from Benicia’s newest award-winning journalism duo, Monica Vaughan and Laura López González. – Roger Straw
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