The federal government said its preliminary report of the May 2015 oil spill at Refugio Beach in southern California found pipeline corrosion to be the culprit.
A pipeline system operated by Plains All American, which has headquarters in Houston, leaked up to 3,400 barrels of oil in Santa Barbara County in mid-May. The company in November indicated the spill volume was around 2,960 barrels and was still working to reconcile the difference. About 30 percent was recovered during remediation efforts.
Migrating to Refugio Beach near Los Angeles and into the ocean, the Environmental Protection Agency characterized the spill as the worst in California in the last 25 years.
The federal Pipeline and Hazardous Materials Safety Administration released their preliminary findings of the integrity of the pipeline system last year. PHMSA said it found "extensive" corrosion, with walls degraded by up to 74 percent of their original thickness in some locations.