In early October, a crack in a pipeline off the coast of Huntington Beach, California spilled some 3,000 barrels (126,000 gallons) of crude oil into the Pacific Ocean. On Saturday, the US Coast Guard announced that it had determined that the container ship MSC Danit had dragged its anchor in heavy weather on January 25, 2021, “in close proximity to a subsea pipeline, which was subsequently discovered to be the source of the Orange County oil spill on October 2, 2021.”

Coast Guard and National Transportation Safety Board (NTSB) marine casualty investigators boarded the container ship MSC Danit in the Port of Long Beach on Saturday.

The environmental monitoring group Skytruth was able to pull up AIS tracks of the container ship as its anchor dragged across the pipeline during the storm.

Investigators believe its anchor dragged for an unknown distance before striking the 16-inch steel pipe, Coast Guard Lt. j.g. SondraKay Kneen said Sunday.

The impact would have knocked an inch-thick concrete casing off the pipe and pulled it more than 100 feet, bending but not breaking the line, Kneen said.

Still undetermined is whether the impact caused the October leak, or if the line was hit by something else at a later date or failed due to a preexisting problem, Kneen said.