BENICIA, CA — Personnel with the Benicia Fire Department were monitoring an oil sheen reported Tuesday by the Valero Benicia Refinery in Sulphur Springs Creek.

The refinery notified the fire department that at 2:50 p.m. Tuesday, a sheen from an unknown type of oil was spotted in the waters of the creek, Benicia Fire Department officials said.

“Valero Benicia Refinery commenced mitigation efforts at 3:20 p.m.,” fire officials said. “The sheen has been contained and proper clean up, notification and mitigation procedures were underway.”

The incident was not a threat to drinking water or public safety although fire personnel will continue to monitor the situation and will update the public if conditions change, fire officials said.

According to a hazardous materials spill report issued by the Governor’s Office of Emergency Services at 3:45 p.m. Tuesday, Valero Energy discovered the sheen at 2:50 p.m. Tuesday. The cause of the Petroleum sheen was not known, nor had the source been determined. Refinery personnel contained the sheen by deploying a boom; cleanup was underway and an investigation was ongoing.