SANTA ANA, California — After a day of "odor surveillance" and other scent-based sleuthing, Southern California air quality investigators confirmed Tuesday what they had already expected — that a pungent, rotten-egg aroma that stretched across the region came from the Salton Sea.
Investigators from the South Coast Air Quality Management District collected air samples, modeled weather patterns and measured hydrogen sulfide levels to determine that Monday's stench came from the saltwater lake 150 miles (240 kilometers) southeast of Los Angeles, as strong winds from a storm churned the water and stirred up foul-smelling gasses from the lake bottom, where they normally are trapped.
A recent fish die-off was likely a contributing factor, said Andrew Schlange, general manager at the Salton Sea Authority.
Modeling showed that a massive thunderstorm could have churned up bacteria and released the stench into the air, where it became trapped by low-hanging clouds.
Investigators also ruled out other possible causes like landfills or oil refineries.