California's Justice Department is now investigating the cause of the oil spill

The California Department of Justice has opened an investigation into the oil spill that occurred off the coast of Huntington Beach this month.

California Attorney General Rob Bonta announced Monday that authorities from his office will work to determine the cause of the spill and what, if anything, could have been done to prevent or minimize it.

"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," Bonta said in a statement.

Investigators for the U.S. Coast Guard so far have determined that the underwater oil pipeline was likely struck by a large ship's anchor. But this hit likely happened several months to even a year before it was discovered on Oct. 1 that tens of thousands of gallons of oil had spilled into the ocean.

The Coast Guard said the anchor of one large ship, or possibly multiple ships, may have hit the pipeline, cracking the concrete casing, but may not have caused the large crack that was discovered last week. The pipeline was also dragged along the sea floor more than 100 feet, according to the Coast Guard.

Amplify Energy has been identified as the company responsible for the pipeline leak, according to Bonta's office.

About 5,500 gallons of crude have been recovered from the ocean so far, the Coast Guard said.

The oil has spread along the California coast with reports of oil coming ashore in San Diego County, some 50 miles from the original site.

Cleanup crews and investigators have found dozens of dead birds and other wildlife, but experts have said the impact on the environment could have been far worse.

On Monday, things were looking up for Huntington Beach and its residents.

Officials there reopened its shoreline after testing of the water showed there were no detectable amounts of oil-associated toxins in the ocean.

"The health and safety of our residents and visitors is of the utmost importance. We understand the significance our beaches have on tourism, our economy, and our overall livelihood here in Huntington Beach," Huntington Beach Mayor Kim Carr said in the announcement. "It is important that our decision to reopen our shoreline and water be based on data and that we continue to monitor the water quality going forward."

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