More than seven years after a spill was first discovered, oil giant Conoco-Phillips has agreed to excavate and clean up the 300-foot oil spill from the Nipomo Creek Pipeline near the Dana Adobe.
The spill was discovered in the subsurface of the creek in May 2003, the result of a leak in a crude oil transport pipeline running to the company’s Nipomo refinery and parallel to the creek. A 2006 investigation confirmed petroleum hydrocarbons released during the leak had entered the groundwater; however, the contaminants are blocked by a clay layer beneath the creek bed and haven’t yet entered the creek, according to soil samples collected by the Central Coast Water Quality Control Board.
“That’s a pretty good-sized spill,” said Scott Milner, inspector for the Environmental Health Services Division of San Luis Obispo County’s Public Health Department. “We don’t see many that big.”
The pipeline was formerly owned by Unocal and is currently operated by Conoco-Phillips, which repaired the pipeline and investigated the spill area for soil contamination in 2005.
The Central Coast Water Board, which is the lead agency handling the case, approved a Corrective Action Plan (CAP) for the site in July of this year. As a result of the agreement, Conoco-Phillips will excavate a 300-foot-by-4-foot-deep area at the bottom of the Nipomo Creek channel, transporting the impacted soil to an authorized waste disposal site.
After being cleared out, the excavated area will be backfilled with clean dirt and the removed vegetation replaced with native plants and trees. The creek banks will also be contoured to prevent erosion.
The cleanup project will require Conoco-Phillips to secure permits from San Luis Obispo County, the California Department of Fish and Game, and the U.S. Army Corp of Engineers, among others.
According to the Water Board, the cleanup could begin as soon as summer of 2011 or 2012, depending on the speed of the permitting process.