A rotten egg or sulfur odor in Richmond was traced to air pollution from the Chevron Refinery that reached more than six times above state standards, the Bay Area Air District said Friday.
The chemical hydrogen sulfide was measured at more than 200 parts per billion (ppb) at 7 p.m. Thursday, the district said.
That is more than six times above the safe baseline of 30 ppb set by California’s Office of Environmental Health Hazard Assessment, the district said. Average concentrations at one monitoring station exceeded the baseline for six out of nine hours, it said.
The release “had serious consequences for our community (including nausea) and impacted residents in the Greater Richmond area, including El Cerrito, San Pablo and Pinole,” District 1 Supervisor John Gioia said in a news release.
“This needs to be investigated as part of the full investigation now underway.”
Supervisor John Gioia
More than 130 complaints were filed with the air district starting at 6:09 p.m. Thursday. Chevron and air district staff who arrived at the refinery about 10:45 p.m. were able to trace the odor to an area of the refinery just downwind of the refinery flares.
The exact source wasn’t immediately identified, the district said. Air district and Contra Costa Fire Protection District Hazmat members were on scene investigating through the evening, according to Gioia.
Chevron released a Level 1 Community Warning System alert at 12:19 a.m. Friday, one step below a public health advisory. It listed the date and time of the release as 12:10 a.m., hours after the complaints began, the district said.
“I am very concerned about the four-hour gap between when the odors were traced to the refinery and when Chevron’s CWS alert went out,” Gioia said. “This needs to be investigated as part of the full investigation now underway.”