A strong rotten egg smell had Southern Californians plugging their noses and crying foul as air quality experts scrambled to determine if the sulphurous scent was coming from the Salton Sea.
Investigators from the South Coast Air Quality Management District were in the field tracking the stench after being flooded with 200 complaints since midnight from across much of the district’s 10,000 square miles, said Sam Atwood, spokesman for the agency.
The odour could be coming from the Salton Sea, a 376-square-mile salt water lake about 150 miles south east of Los Angeles. Another source could be a wastewater treatment plant, Mr Atwood said, but officials have not found any indication that’s the case.
“The odour was extremely intense,” said Janis Dawson of the Salton Sea Authority. “We actually thought that somebody had an accident, a broken sewage main, that’s how strong it was.”
The dying sea, a major resting stop for migrating birds on the Pacific Flyway, has been plagued by increasing salinity. It was created in 1905 when floodwaters broke through a Colorado River irrigation canal.
It is expected to shrink significantly by 2018 and become saltier, severely impacting fish and bird habitats.
The sea had a fish die-off within the past week and that, combined with strong storms in the area late Sunday, could have churned up the water and unleashed bacteria from the sea floor that caused the stench, said Dawson. Gusts reached 55mph during the windstorm and accompanying downpour, she said.
The smell does not pose any health hazards, but it generated an explosion of quips on social media, as people from Riverside County to the San Fernando Valley north of Los Angeles complained and sought information.
Jose Chavez, a 28-year-old comedian who lives in San Fernando, tweeted: “The Valley is starting to smell like rotten eggs. In an unrelated note, Febreeze sales are through the roof in the San Fernando Valley.”
Chavez was leaving the grocery store when he was overwhelmed by the odour, he said.
“My first thought was that maybe one of the eggs I bought was rotted and I got back home and the smell was still there so then I started to think it was me so I changed my clothes,” he said. “It was very pungent.”
The Los Angeles Fire Department said residents did not need to make emergency calls to report the stink and at least one primary school cancelled break time.
Jack Crayon, an environmental scientist at California’s Department of Fish and Game, said he recognised the smell as the typical odour when winds churn up the sea’s waters and pull gases from the decomposition of fish or other organisms up to the surface.
He said the phenomenon typically occurs a few times a year in the area surrounding the lake, but it was unusual for the smell to spread so far.
Julie Hutchinson, battalion chief at California Department of Forestry and Fire Protection in Riverside, said heavy cloud cover lingering over the area had trapped the smell in the suburbs east of Los Angeles.
The smell was reported as far away as Palmdale and Lancaster, more than 150 miles north of the Salton Sea.
“It’s just not able to evaporate up into the atmosphere,” Ms Hutchinson said. “The moisture and thick heavy air is keeping it in the lower ends of the valleys.”
The smell was starting to dissipate yesterday as winds picked up speed, she said.
The Salton Sea is about one-third saltier than the ocean and sits 200ft below sea level.
It relies on water that seeps down from nearby farms, and it has been plagued with fish die-offs that result from low oxygen levels in the water and receding shorelines.