Approximately 74,000 pounds of sulfur have been released into the atmosphere since the Valero Benicia Refinery shutdown on May 5, according to a report the company submitted to the California Office of Emergency Services.
On May 5, a disruption at the refinery led to a power outage. After power was restored, a large plume of black smoke was released for several hours, resulting in the Industrial Park being placed on lockdown and nearby Robert Semple and Matthew Turner elementary schools establishing shelters-in-place. The lockdown was lifted around 5 p.m. that afternoon.
Since then, The Bay Area Air Quality Management District (BAAQMD) has been investigating the incident and reviewing all the flareup reports submitted by the facility.
For the past few weeks, the refinery has been testing equipment and trying to bring things back up to speed, according to Tom Flannigan, BAAQMD’s public information officer. A week ago, the refinery was operating again, but there were some issues with the startup. These issues lead to some flaring at the refinery, and the air district has been investigating those issues and flareups, Flannigan said.
“Flaring is a normal process when a facility has gone through an upset,” he said. “That’s what happened on May 5 when they lost all power. The facility went through an upset, and they have to bring themselves back to a steady state.”
The gases released from flareup rises to the highest parts of the atmosphere and dissipates, according to Flannigan. It is a normal requirement for facilities to reduce impacts of pollution and emergency situations should they arise, the public information officer said.
“When upsets like these happen, facilities review their equipment, they do some maintenance, they make fixes, they make upgrades so that they adjust the processes so that they can bring the facility back up safely,” he said. “All the flaring that they have done, they have to report it to us. We have been trying to work with them to work through these issues. They have a flare minimization plan that they are required to take steps to mitigate this from happening again.”
Flannigan says the district only has regulations they can enforce, but the air district has been working with the refinery to come up with plans so it does not have a repeat of the shutdown incident. According to Flannigan, the air district will be working with the refinery to put new procedures in place to prevent another shutdown from happening, and both parties may collaborate in installing safety mechanisms as fail safes in order to stop another power outage-caused shutdown from occurring at the facility again.
“The air district is committed to making sure that this facility operates safely and that they are commited to the requirements of limiting the amount of flaring,” Flannigan said. “We’re working with them to make sure the impacts on our air quality is limited and within the regulations.”

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