More than 50 reports of mystery rotten egg smell in SF

The San Francisco Fire Department responded to more than 30 calls about a mysterious smell of rotten eggs or sulfur overnight, officials said. The San Francisco Fire Department responded to more than 30 calls about a mysterious smell of rotten eggs or sulfur overnight, officials said. Photo: Bill Hutchinson / The Chronicle / / Photo: Bill Hutchinson / The Chronicle / / Image 1 of / 1 Caption Close More than 50 reports of mystery rotten egg smell in SF 1 / 1 Back to Gallery

Crews responded to more than 50 calls Wednesday from San Francisco residents complaining of the smell of rotten eggs or sulfur — and while the odor eventually dissipated, the cause and origin of the foul scent remained a mystery.

Pacific Gas and Electric Co. and the San Francisco Fire Department began receiving calls about the smell of gas across the city around 2 a.m. Wednesday, PG&E spokesman J.D. Guidi said.

The majority of the calls came from neighborhoods around the bay coastline like the Bayview and the Marina, with other reports coming from South of Market, the Outer Richmond and Sunset neighborhoods, said Lt. Jonathan Baxter, a San Francisco Fire Department spokesman.

PG&E crews investigated 54 reports of the rotten egg smell, but found no leaks or gas readings, Guidi said. No customers reported losing gas service.

“This does not appear to be related to PG&E facilities,” he said.

By 7 a.m. Wednesday, the odor had dissipated and there was no threat to public health or safety, Baxter said.

Investigators did not immediately find a cause or origin of the smell, Baxter said.

The Fire Department was working with other city agencies to pinpoint what caused the mysterious odor while PG&E continued to monitor the air.

A spokeswoman for the Chevron Richmond Refinery said the plant had done some flaring around midnight Wednesday, but that their investigation showed it was not the cause of the odor.

The U.S. Coast Guard, meanwhile, said it did not receive reports of any spills that may have been a source of the odor.

Officials with the Bay Area Air Quality Management District said they were looking into the matter but so far have not received any complaints.

Evan Sernoffsky is a San Francisco Chronicle staff writer. Email: esernoffsky@sfchronicle.com Twitter: @EvanSernoffsky