california local news

Cause of oil sheen off California coast still undetermined, but contained, Coast Guard says

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By Yosi Yahoudai
Founder and Managing Partner

What caused a 2-mile long oil sheen spotted offshore of Huntington Beach late last week is still unclear, but enough has been cleaned up for the emergency response effort to come to an end, United States Coast Guard officials announced Monday afternoon.

The sheen spotted March 7 prompted quick response from the United Command, a group of several agencies that combine efforts to contain oil off the coast, formed following the 2021 oil spill in the same area that reached shore and impacted everything from beach access to businesses along the coastline.

Preliminary laboratory results of samples of the oil analyzed by the Office of Spill Prevention and Response – part of the Department of Fish and Wildlife – confirmed the release is lightly weathered crude oil and not a refined product, such as gasoline or diesel, but the Petroleum Chemistry Lab was unable to definitively identify the oil source, the Coast Guard said in its announcement Monday.

Clumps of tar lay among the other debris on Huntington Dog Beach in Huntington Beach on Saturday morning, March 9, 2024. The United States Coast Guard received a report on Thursday evening, March 7, from the National Response Center about a 2-mile-long oil sheen off Huntington Beach’s coast. (Photo by Mark Rightmire, Orange County Register/SCNG) 

The samples are consistent with local crude oil, officials said, with characteristics of the Monterey Formation, and not imported oil that may have been brought by ship to California.  The lab results were also inconsistent with archived samples from oil platforms in the area.

Earlier in the day, US Coast Guard public affairs specialist Richard Uranga said samples were thought to be from natural sources of seepage. But later in the day, a Coast Guard update said lab results were also inconsistent with archived samples from the area of both refinery oil and naturally released oil.

The samples do not match any in the CDFW database that covers the past 25 years, said Coast Guard Petty Officer Richard Brahm.

“That’s really where we’re at. They’ll keep taking samples of all this stuff until maybe they get a hit, or maybe they don’t,” he said. “I wish we had an answer. It’s definitely from the area, but we can’t pinpoint where it came from.”

The Coast Guard received a report about 7 p.m. on Thursday, March 7, from the National Response Center about the sheen on the ocean’s surface off Huntington Beach’s coast. It was first spotted about 2.8 miles off Huntington Beach near two oil platforms, Emmy and Eva.  It was visually confirmed at first light the next day and containment efforts began.

Operations are now complete, currently in the “decontamination phase” cleaning booms and boats, Uranga said.

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, according to the USCG statement.

According to the National Oceanic Atmospheric Administration, crude oil entering the ocean is known as “seeps” and add about five million gallons of oil into the ocean each year.

While seeps are from a natural source, they can appear similar appearance and behavior and have similar effects as oil released during drilling and other human activities.