Investigation into rotten egg smell in SF, Richmond narrows

Air quality experts continue to investigate the source of the rotten egg stench that wafted over San Francisco and Richmond for two days in December, ruling out sources on the San Francisco Bay including ships and oil spills.

Officials from the Bay Area Air Quality Management District and Contra Costa Health Services said they are focusing their joint efforts on flaring incidents at the Chevron refinery, landfills, and the wastewater treatment plant in Richmond as possible culprits for the foul odor that surrounded the cities on Dec. 28 and 29.

PG&E officials in December ruled out the possibility that the nearly 70 reports of sulfur smells received in San Francisco over the two days were caused by a gas leak.

In order to eliminate other sources and pinpoint the origin of the odor, the air district is currently reviewing all flaring records, in-stack monitor data, sampling data and air monitoring data for all industrial facilities in Richmond.

“Contra Costa Health Services staff are in discussions with Chevron on their notifications of the two flaring incidents and the high readings of hydrogen sulfide from a ground level monitor located in Point Richmond,” Randy Sawyer, Chief Environmental Health and Hazardous Materials Officer said in a statement.

Braden Reddall, a spokesman for Chevron, said the company sent a 72-hour report to the air district following the two flaring events, which showed the emission levels were well within applicable limits.

Reddall said Chevron would continue to cooperate with the investigation.

In a statement, air district executive officer Jack Broadbent said the Air District would continue to build a case for potential violations against the responsible facility.

As the joint investigation continues, which will likely be for several weeks, air quality officials will release results and possible violations against the facility at fault.

If you find our journalism valuable and relevant, please consider joining our Examiner membership program.
Find out more at

Just Posted

Lowell High School is considered an academically elite public school. (Kevin N. Hume/S.F. Examiner)
Students denounce ‘rampant, unchecked racism’ at Lowell after slurs flood anti-racism lesson

A lesson on anti-racism at Lowell High School on Wednesday was bombarded… Continue reading

Scooter companies have expanded their distribution in neighborhoods such as the Richmond and Sunset districts. (Kevin N. Hume/S.F. Examiner)
SFMTA board signs off on changes to scooter permit program

Companies will gete longer permits, but higher stakes

A health care worker receives the Moderna COVID-19 vaccine. (Go Nakamura/Getty Images/TNS)
City sets ambitious goal to vaccinate residents by June

Limited supply slows distribution of doses as health officials seek to expand access

U.S. President-elect Joe Biden and Jill Biden arrive at Biden's inauguration on the West Front of the U.S. Capitol on January 20, 2021, in Washington, DC.  (Win McNamee/Getty Images/TNS)
Joe Biden issues call for ‘unity’ amidst extreme partisan rancor

‘I will be a president for all Americans,’ he says in inauguration speech

MARIETTA, GA - NOVEMBER 15: Democratic U.S. Senate candidates Jon Ossoff (R) and Raphael Warnock (L) of Georgia taps elbows during a rally for supporters on November 15, 2020 in Marietta, Georgia. Both become senators Wednesday.  (Jenny Jarvie/Los Angeles Times/TNS)
Vice President Harris swears in senators Padilla, Warnock, Ossoff

New Democratic senators tip balance of power in upper legislative house

Most Read