HUNTINGTON BEACH, Calif. — A Southern California underwater oil pipeline was likely struck by an anchor several months to a year before a leak spilled tens of thousands of gallons of crude, the U.S. Coast Guard announced Friday.
A large vessel of some kind may have struck the massive pipeline, shattering the concrete casing but not necessarily causing the slender crack from which oil spewed last weekend, said Capt. Jason Neubauer, chief of the Coast Guard’s office of investigation and analysis.
The longer timeline was partly based on marine growth that was spotted on the pipe in an underwater survey. The pipe, which was found to be intact last October, may also have been struck several other times by other ships’ anchors over the course of the period, he added. No ships have been identified, however.
“We’re going to be looking at every vessel movement over that pipeline, and every close encroachment from the anchor just for the entire course of the year,” the captain said.
The pipeline was dragged along the sea floor as much as 105 feet, Neubauer said.
That indicates a large vessel was involved, he said. Cargo ships with multiton anchors routinely move through the area from the ports of Los Angeles and Long Beach.
At least 17 accidents on pipelines carrying crude oil or other hazardous liquids have been linked to anchor strikes or suspected anchor strikes since 1986, according to an Associated Press review of more than 10,000 reports submitted to federal regulators.
According to federal records, in some cases an anchor strike is never conclusively proven, such as 2012 leak from an ExxonMobil pipeline in Louisiana’s shallow Barataria Bay, where a direct strike by a barge or other boat also were considered possibilities.
In others the evidence of an anchor strike was obvious. During 1992’s Hurricane Andrew, a 30,000-pound anchor was dragged by a drifting drilling rig over a Texaco pipeline in the Gulf of Mexico, causing a dent that broke open when the line was later re-started.