The California Department of Justice is investigating the oil spill off the coast of Huntington Beach.
The agency said it would work with state, local, and federal authorities to determine the cause of the spill if anything could have been done to prevent the disaster.
"The oil spill off the coast of Huntington Beach is an environmental disaster with far-reaching consequences for our fish and wildlife, for our communities, and for our economy," said Attorney General Rob Bonta, in a news release.
The cleanup continued a week after the spill. To date, 5,544 total gallons of crude oil have been recovered by vessel. Some 13.6 barrels of tar balls were recovered Saturday. About 250,000 pounds of oily debris has been recovered from shorelines. Some 11,400 feet of containment boom have been deployed.
Contracted cleanup teams were cleaning locations from Seal Beach to San Onofre Beach, while officials were conducting water and soil sampling along San Onofre Beach.
Meanwhile, the Oiled Wildlife Care Network reported that its responders had recovered 58 species impacted by the spill as of Sunday, 50 birds and eight fish. Twenty-six of the birds were recovered alive, but all eight of the fish were dead.
The leak was reported on the morning of Oct. 2 a few miles off the Huntington Beach coast, although some boaters reported smelling something in the water Friday.
Authorities initially estimated that as much as 144,000 gallons of oil may have leaked from the damaged pipeline, but officials said Thursday the actual amount is likely much lower, although there is still no firm number. At a news conference Thursday afternoon, USCG Capt. Rebecca Ore estimated that roughly 588 barrels of oil had spilled, which would equate to about 24,700 gallons. That's being considered a minimum amount leaked, but officials were unsure of a possible maximum number.
Crews responded to the leak last Saturday morning, and beaches were quickly closed as authorities realized the size and scope of the oil slick.
Amplify CEO Martyn Willsher insisted the company was unaware of any release of oil into the ocean until about 8 a.m. Saturday, adding that the firm responded and reported the incident immediately.
The Coast Guard's lead investigator said the ruptured underwater pipeline might have been damaged several months to a year ago, adding that it's unclear when the crack occurred or when oil began seeping into the water.