Odor across Richmond and San Pablo traced to Chevron refinery

A smell drifted across Richmond and San Pablo Thursday night, with residents describing it as anything from rotten eggs and sulfur to sewage. Today, the Bay Area Air District traced the hydrogen sulfide odor to an area of the Chevron refinery just downwind of its flares.

The district’s incident report, released Friday morning, said the exact source within the refinery had not been identified and the investigation was ongoing.

By Friday evening, Chevron said it believed it had found the source but did not say what it was or confirm the refinery caused the odor. The company has been investigating conditions at the refinery since Thursday night, according to Caitlin Powell, a spokesperson for Chevron, who released a statement late Friday afternoon.

“We recognize that a recent odor has been disruptive and concerning for our community,” the statement said. “We believe we have identified the source and are working to mitigate it. We will continue to engage with the City of Richmond, Bay Area Air District and County Health and will share more information as it becomes available.”

The district began receiving complaints at 6:09 p.m. October 22 and had received more than 130 by Friday. Staff traced the odor to the Castro Street and Richmond Parkway area by about 8:30 p.m. The smell was strongest near Vernon Avenue and Seventh Street.

The district’s Seventh Street monitor recorded a peak one-hour average above 200 parts per billion at 7 p.m. The state’s acute health guideline for one-hour exposure is 30 parts per billion. Readings at the station exceeded that level for six of the nine hours between 5 p.m. Thursday and 1 a.m. Friday.

Chevron’s monitors also recorded hydrogen sulfide levels above the guideline, from North Richmond to Atchison Village. At 7:05 p.m., a Chevron fenceline monitor on the refinery’s east side near Castro Street read 30.7 parts per billion while winds blew from the west across the refinery, according to the company’s air monitoring website. Levels in Point Richmond later rose to about 10 parts per billion. All monitors returned to typical background levels by 4 a.m. Friday.

Air District staff arrived at the refinery at 10:45 p.m. and worked with Chevron staff on the investigation.

Chevron issued a Level 1 Community Warning System alert at 12:19 a.m. Friday. The alert reported an ongoing hydrogen sulfide release that had moved offsite and listed the release as beginning at 12:10 a.m. The Air District disputed that time.

“While the alert lists the date and time of release at 12:10 am on October 23, community complaints and Air District staff observations suggest the release occurred hours earlier, during the evening of October 22,” the district’s incident report says.

This is a developing story and will be updated as more information becomes available.