2 Chevron Refinery Malfunctions May Have Caused Mysterious SF Stink

Chevron has released information that may explain why many San Francisco residents reported a sulfuric, rotten egg stench wafting through the city for two days in a row last December.

After PG&E received numerous calls from San Francisco residents on December 28th and 29th, air quality officials began investigating two separate incidents at the Chevron refinery in Richmond that may have sent large amounts of toxic gas into the city.

As KQED reports, the company has given Contra Costa County officials two reports that reveal that the incidents were caused by clogged pump line in the refinery and a communication breakdown between plant workers. However, the county's chief environmental health and hazardous materials officer maintains that neither report actually explains why high levels of hydrogen sulfide were measured near the facility.

The first malfunction started at 11:45pm December 27th when a line that empties a tank, also known as a "liquid knockout drum," became clogged. KQED reports that the company has not disclosed what caused the clog and doesn't appear to be investigating the cause.

The second incident, the result of an human error, occurred 16 hours later. A compressor that was restarted after a maintenance shutdown began malfunctioning because it had nothing to compress. The compressor was then shut down again for more than three days.

Both occurrences activated the refinery’s flaring system.

PG&E received 54 calls from San Francisco residents after the first incident, and 15 calls after the second. Most of the calls came from neighborhoods near the waterfront, including Bayview, the Marina, the Outer Sunset and Richmond, as well as SoMa.

In a recent interview with KQED, Randy Sawyer, Contra Costa County’s chief environmental health and hazardous materials officer, noted that despite the reports, Chevron officials told his office that they are still investigating what caused the company's air monitors in Point Richmond to detect an "abnormally" high amount of hydrogen sulfide.

Contra Costa County officials aren't the only ones investigating December's stink. In January, District 2 Supervisor Mark Farrell called for a series of hearings with Chevron executives. The Bay Area Air Quality Management District is also conducting its own investigation.

In the meantime, Chevron's reports say that the company has asked contract workers to better stick to company standards when installing devices at the refinery. The company also plans to look into possible upgrades to the Richmond refinery's alarm systems.

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2 chevron refinery malfunctions may have caused mysterious sf stink