The Harbert Oil Company facility is located in a remote area about two hours northeast of Redding, California. The client retained VESTRA in 2005 after a previous consultant failed to reduce onsite contaminant levels after nearly five years of remedial activities. Contaminants already forced destruction of an onsite supply well and threatened a domestic production well located 400 feet downgradient from the site at a community medical center.

To characterize the contaminant plume and fill in essential data gaps quickly, VESTRA implemented an extensive field investigation in June 2006. VESTRA defined the constituents, magnitude, and extent of soil and groundwater contamination and the remedial design necessary to achieve compliance with regulatory cleanup requirements and standards for leaking underground storage tanks. As part of the investigation, 19 continuous core soil borings were installed to a depth of about 80 feet below the ground surface. Geotechnical analyses were conducted on samples from representative lithologies to more accurately determine fate and transport characteristics such as retardation, intrinsic permeability, adsorbed mass, and degradation rates.