Oil sheen off California remains a mystery with no definitive source pinpointed

Samples from an offshore sheen and tar balls along the shoreline have been gathered to help uncover the source of an oil sheen observed off the coast of California’s Huntington Beach, but the exact match remains undetected.

In response to the oil sheen spanning 2.5 miles in length and 0.5 miles in width, roughly 2.8 miles off Huntington Beach near the Emmy and Eva platforms, representatives from the U.S. Coast Guard (USCG), California Department of Fish and Wildlife’s Office of Spill Prevention and Response (CDFW-OSPR), and Orange County Sheriff’s Department established a Unified Command, which concluded its activities on March 11.

The Coast Guard confirmed that cleanup crews recovered around 85 gallons of product from offshore recovery efforts and removed roughly 1,050 pounds of oily waste/sand and tar balls from the shoreline during the weekend. However, the official product quantification collected throughout the response is ongoing.

Capt. Ryan Manning, federal on-scene coordinator for the response, commented: “In the face of this environmental challenge, the strength of our partnerships has once again proven to be our greatest asset. The Coast Guard, the California Department of Fish and Wildlife’s, Office of Spill Prevention and Response, and our local Orange County agencies and departments mobilized swiftly to mitigate the impact of the oil sheen off Huntington Beach.

“This operation underscores the importance of readiness, collaboration, and a shared dedication to preserving the natural beauty and health of our environment. As we conclude this response, we remain vigilant and prepared to respond to future incidents, ensuring the protection of our marine and coastal resources for generations to come.”

While samples from the offshore sheen and tar balls along the shoreline were collected to help determine the source of the oil, analyses by CDFW-OSPR’s Petroleum Chemistry Lab were “unable to definitively identify the oil source,” according to the U.S. Coast Guard.

Despite not being able to zero in on the exact source, the preliminary laboratory results of the collected oil samples still confirm that the release is lightly weathered crude oil and not a refined product like gasoline or diesel, indicating 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.

Furthermore, the preliminary laboratory results also 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. These lab results were inconsistent with archived samples from oil platforms in the area.

Although a discharge of produced water from the Elly platform was reported on the morning of March 8, the Coast Guard is adamant that the characteristics of the produced water do not align with what was observed from the sheen. The USCG underlines that samples will be taken for additional analysis if another release is observed while Huntington Beach Lifeguards will continue to monitor the beach for tarball conditions that exceed characteristics associated with natural seeps in the area.

After the 2021 oil spill off the coast of Orange County, California put more gumption into its efforts to end offshore drilling, as demonstrated by Senator Dave Min’s Senate Bill (SB) 559, which overcame its first legislative stumbling block in January. The bill will require the California State Lands Commission to take immediate steps to end the remaining leases for offshore oil drilling in California waters.

This follows Governor Newsom’s support for a lawsuit filed in San Francisco County Superior Court last year against ExxonMobil, Shell, Chevron, ConocoPhillips, BP, and the American Petroleum Institute (API).