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.

During the flaring incident, complaints of strong odors arose, leading to an investigation.

"A unit at the refinery went down...which caused the product to need to be moved between two tanks. It was discovered that in the process of moving the product, some of it got on the lid of a tank and that was the source of the strong odor," according to a post from the Benicia Fire Department.

The spilled material, which had a chemical composition similar to light oil and generically referred to as "slop," was emitting hydrogen sulfide and sulfur dioxide, causing an unpleasant odor experienced by surrounding residents, according to CalEMA and the Benicia Fire Department. The odor incident at Valero's refinery "reached the threshold for a Level-3 incident," according to a press release from the City of Benicia, California's website, and Valero is required to submit a 72-hour report to the city.

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 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.

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.


This content was created by Oil Price Information Service, which is operated by Dow Jones & Co. OPIS is run independently from Dow Jones Newswires and The Wall Street Journal.


--Reporting by My Nguyen, mynguyen@opisnet.com; Editing by Bayan Raji, braji@opisnet.com


(END) Dow Jones Newswires

02-28-24 1814ET