Leaking pipeline likely was hit before

HUNTINGTON BEACH, Calif. — An underwater oil pipeline off the Southern California coast was likely damaged by a ship’s anchor several months to a year before it ruptured and sent oil spewing into the ocean and then onto some of the area’s best-known beaches, investigators said Friday.

Coast Guard Capt. Jason Neubauer, chief of the office of investigations and analysis, said after the first strike it’s possible other ships’ anchors subsequently struck the steel pipe that brings oil to shore from three platforms out at sea. Investigators previously said a large section of the pipe was bowed after being struck and dragged along the seabed.

It remains unknown when the slender, 13-inch crack began leaking oil, and investigators will pore over a year of data on ship movements near the area of the break. No ships have been identified as suspects at this point.

“We’re going to be looking at every vessel movement over that pipeline, and every close encroachment from the anchorages for the entire course of the year,” Neubauer said.

The accident scene is outside the Long Beach-Los Angeles port complex that is the largest in the country and handles some 4,000 vessels a year. Many of them are from overseas and that could complicate the process of boarding ships of interest in the investigation to get information.

The disclosure that the damage to the pipe could have occurred so long ago dramatically reshaped what was known about the leak that sent tens of thousands of gallons of crude into the Pacific. A search that initially appeared to focus on the hunt for one vessel now could send investigators to ports around the country to inspect many ships.

Neubauer said investigators have narrowed their search to large cargo vessels that would be powerful enough to move a 4,000-foot section of pipeline 105 feet across the ocean floor. He also said investigators have zeroed in on a windy storm Jan. 24-25 that could have caused problems for ships trying to anchor in the vicinity of the twin ports.

Investigators believe the initial anchor strike occurred sometime after a survey of the pipeline a year ago that showed the line was in its original location. The extended timeline was partly based on visible marine growth on the damaged length of the pipe that was revealed in an underwater survey.

A crack suggests the pipe, which was installed in 1980, perhaps withstood an initial impact, but had been weakened over time by corrosion and became more prone to fail, said Ramanan Krishnamoorti, a petroleum engineering professor at the University of Houston.