Exxon Mobil Corp's 149,500 barrel per day (bpd) Los Angeles-area refinery in Torrance, California, reported a breakdown on Saturday that triggered flaring, according to a notice the company filed with state pollution regulators.

The breakdown triggered the released of over 500 pounds of sulfur dioxide into the atmosphere, according to the notice filed with the California Emergency Management Agency.

The notice did not say which unit or units broke down.