Following the successful pattern established at the former Aliso Street MGP, Tetra Tech has been successfully conducting environmental investigations, risk assessments, and soil removal actions at this approximately 9 acre site for the past 10 years by working in close coordination with the regulatory agencies involved. Evaluation of the soil and groundwater at this site has been made more challenging, because part of the site was redeveloped as an oil tank farm and there was a large leak that resulted in a deep groundwater plume extending beneath the area where the major MGP facilities were located.