People in Santa Fe Springs, Norwalk, Whittier and Pico Rivera reported smelling ammonia, sewage, garbage, gas and rotten eggs, among other things.
"It's nothing new in this area," said Everett Muhammad. "This area has a bad, putrid smell all the time, I don't know if it's poisonous gas."
The strong stench is from a wastewater facility at the south end of the city that has left a stink in the neighborhood before.
According to the Air Quality Management District, the smell is due to non-toxic hydrogen sulfide coming from Ridgeline Energy Services U.S.A. The Santa Fe Springs-based facility processes non-hazardous industrial water for treatment and discharge into sewers.
The city of Santa Fe Springs confirmed the source Monday afternoon.
In a statement the city said the odor comes from a former oil refinery located on Lakeland Road. The removal of wastewater tanks has aggravated the situation, according to the city. Water in the tanks has remained untreated and has not been discharged, changing the chemical composition inside to produce strong sulfur odor. The city said the marine layer outside exacerbated the problem by preventing the smell from dissipating in the air as normal.
The city said the smell is due to one remaining un-repaired tank. The repair of that tank was expected to be completed "over the next few days."
The city said the water was being treated to increase pH levels to suppress further sulfur odors.
In July, Ridgeline Energy Services U.S.A. made headlines for the same reason. More than 100 emergency calls were made then about a stench of rotten eggs in the air.
It was determined then that a wastewater tank on the property had a leak in its roof and that's what was causing called hyrdrogen sulfide to spread through the area. Deemed a nuisance by the AQMD, the city was then cited for the smell seeping through holes in its water tanks.
The haunting smell has returned two months later and inundated the city again, leaving people furious.
"Today is the probably one of the worst I've ever smelled it since we've been here," said Brad Simmons. He runs B & G Millworks across the street from the Santa Fe Springs faciilty and says the smell is so bad his employees have been forced to wear gas masks.
"It's been bad for about a year or so. From time to time, the smell just overwhelms us," said Simmons.
Christine Makshanoff is sick of the smell.
"I haven't been able to open my windows for six months in a senior complex," said Makshanoff. "I'm getting burning of the throat and nausea."
It was not immediately known if the AQMD has cited the company for the newest incident. Ridgeline Energy Services U.S.A. has to present AQMD with a status report on the issue Wednesday.