Southern California oil sheen is unlikely to stem from leakage, tests show

An oil sheen that surfaced in the Pacific Ocean off the coast of Southern California last week does not appear to have been caused by an oil spill, U.S. Coast Guard officials said Monday.

Oil samples collected from the sheen, which was about 2.5 miles (4 km) long and 2,600 feet (800 meters) wide, did not match anything that might have leaked from any of the oil rigs or ships into the water near Huntington Beach, California, according to preliminary tests. by the State Leakage Prevention and Control Bureau.

The samples had characteristics of “freshly produced oil” from the local Monterey geological formation and were more consistent with oil that seeps naturally from the seabed, although tests could not definitively determine their origin, the Coast Guard said.

“We have many samples from all the rigs and their products, as well as the oil that was in the oil sheen,” said Petty Officer Richard Uranga, a Coast Guard spokesman. “The oil does not appear to be related to the oil rigs.”

The sheen was first spotted Thursday evening about 1.5 miles offshore of Huntington Beach, where there is significant offshore oil activity.

The discovery raised concerns that equipment from those operations was leaking oil into the Pacific Ocean — a particularly alarming prospect in the wake of a major oil spill in the same area in 2021, in which 25,000 gallons of crude oil gushed from a crack in a pipeline and into the sea. The leak resulted in federal charges against three companies.

The Coast Guard, as well as state and local agencies, investigated the new shine this weekend. Crews cleaned up about 20 gallons of oil off the coast and removed about 1,050 pounds of oily sand and tar balls from the coast, the Coast Guard said. The various agencies have completed their response to the incident.

In Huntington Beach, colloquially known as Surf City, beaches remained open through the weekend and into Monday despite what appeared to be an increase in the appearance of tar balls, said Jennifer Carey, a city spokeswoman.

She said tar balls have been washing up regularly since the 2021 oil spill. Still, the city continued to monitor the situation, Ms. Carey said, adding that if beachgoers see tar on the beach they should avoid it. If visitors see an area with heavy contamination, she added, they should report the situation to a lifeguard.