An odor advisory has been issued for the Coachella Valley area of Southern California because of naturally occurring processes in the Salton Sea that produce a gas with a rotten egg smell.
The South Coast Air Quality Management District issued the advisory Sunday due to elevated levels of hydrogen sulfide detected immediately downwind of the huge desert lake.
The agency says over the past week concentrations of the gas have been elevated when winds are blowing out of the south, and that wind condition is expected to continue during daylight hours through Tuesday.
The Salton Sea, about 160 miles southeast of Los Angeles, was formed by an engineering project accident in 1905 that sent water from the Colorado River to the sea bed. It became the state's biggest lake.
Billed as the Salton Riviera, developers saw an opportunity and built hotels, yacht clubs and residences. The mid-20th-Century tourist resort of Bombay Beach was on the northeast lake shore.
The ecosystem rapidly began to deteriorate by the 1970s, due in part to the lack of a drainage outlet for the sea's polluted and de-oxygenating water.
NBC4's Jonathan Lloyd contributed to this report.
