Technicians with the South Coast Air Quality Control District said they believe the stink is an ocean-based natural occurrence blowing ashore from the Santa Monica Bay.
Santa Monica hazmat crews found unusual concentrations of odorless methane gas in the air.
Officials believe either a pocket of stinky algae, or a bubble of methane laced with sulfurous gas, surfaced in the ocean.
The Los Angeles Fire Department said they received many calls about the smell.