HOUSTON (Reuters) -According to the agency, the U.S. shore Guard was attempting to locate the cause of an oil spill off the shore of Huntington Beach, California, on Friday.

A Coast Guard helicopter flying over the site around sunrise noticed the sheen, which was believed to be 2.5 miles (4 km) long and 0.5 miles (800 metres) wide.

The Coast Guard said that although it was unknown which of the two oil drilling rigs was the source of the spill, it was around 2.8 miles (4.5 km) off Huntington Beach.

According to a regulatory filing, Beta Offshore, a division of Amplify Energy (NYSE: AMPY) Corp., reported a possible produced water spill on Friday from its offshore Platform Elly off Huntington Beach. As a result, the firm had to shut down a pipeline.

It was unclear if the incident was related to the huge oil sheen that the Coast Guard observed on Friday.

Amplify Energy said, “At this time, we do not indicate that this sheen is related to our operations.”

Following a massive crude oil spill in October 2021, Amplify Energy Corp agreed in September 2022 to pay approximately $5 million in penalties and fines and to plead not guilty to six criminal counts.

Around 588 barrels (24,696 gallons) of oil seeped from an undersea pipeline that connected the company’s Elly platform in Long Beach to the Huntington Beach coast during that same disaster.

Since the 1980s, the Elly platform has been in operation.

Brady Bradshaw, Senior Oceans Campaigner at the Centre for Biological Diversity, stated, “It’s time for state and federal regulators to take tough, urgent action to get this decrepit infrastructure out of the ocean.”

California’s oil production has been steadily declining for almost 40 years, and this year, Exxon Mobil (NYSE: XOM) and Chevron (NYSE: CVX) wrote down a combined $5 billion worth of its Californian properties.

Exxon claimed that the regulatory framework hindered its operations in the state.