Valero’s 149,000 b/d Benicia refinery in Northern California experienced flaring on Saturday following an unplanned unit shutdown, according to a Hazardous Materials Spill Report filed with the California Governor’s Office of Emergency Services.
Investigation Underway
Chemical Composition and Odor
The spilled material, referred to as “slop,” had a chemical composition similar to light oil and was emitting hydrogen sulfide and sulfur dioxide, resulting in an unpleasant odor experienced by surrounding residents, according to CalEMA and the Benicia Fire Department. The incident reached the threshold for a Level-3 incident, as stated by a press release from the City of Benicia’s website. Valero is obligated to submit a 72-hour report to the city.
Response and Mitigation
The Benicia Fire Department responded by assessing and mitigating the impact on public health in coordination with Solano County Public Health and Air District staff. Portable air monitors were deployed throughout the city to track air quality.
Efforts to Clean Up Spill at Valero Benicia Refinery Underway
Flaring Continues as Investigation Into Incident Progresses
Efforts to clean up the spill on the tank lids commenced promptly, while intermittent flaring continued due to the ongoing unit shutdown. It’s estimated that over 1,000-lbs of sulfur dioxide was released during the flare event, according to a Hazardous Materials Spill Report filed with the California Governor’s Office of Emergency Services.
Valero Benicia confirmed the cessation of flaring activity and that the odor has dissipated, according to a press release from the City of Benicia’s website.
Ongoing Investigation and Reports
The investigation of the incident is ongoing, and Valero is required to submit a 30-day report with root cause analysis. Separately, Solano County Environmental Health will work with the City of Benicia to perform a full incident investigation that will also be released publicly.
Representatives for Valero’s Benicia, California refinery did not immediately respond to requests for comment.