The Unified Command concluded its response to an oil sheen observed offshore of Huntington Beach, California on Monday, but the source of the oil remains unclear.
Over the weekend, cleanup crews recovered approximately 85 gallons of product from offshore recovery efforts and removed roughly 1,050 pounds of oily waste/sand and tar balls from the shoreline.
The U.S. Coast Guard and the California Department of Fish and Wildlife, Office of Spill Prevention and Response (CDFW-OSPR) collected samples from the offshore sheen and tar balls along the shoreline to help determine the source of the oil. Analyses by CDFW-OSPR's Petroleum Chemistry Lab were unable to definitively identify the oil source.
However, the preliminary laboratory results of the oil samples collected confirm that the release is lightly weathered crude oil and not a refined product like gasoline or diesel. They also indicate that the samples are consistent with local crude oil with characteristics of the Monterey Formation and not imported crude oil that may be brought by ship to California.
The preliminary laboratory results indicate that the oil samples analyzed from this incident are more characteristic of freshly produced oil than heavily weathered oil, which is associated with typical natural seeps. The lab results were also inconsistent with archived samples from oil platforms in the area. While a discharge of produced water from Platform Elly was reported on the morning of March 8, the characteristics of the produced water do not align with what was observed from the sheen.