ERAS performed a Phase 1 project for a medical office building. Review of city records indicated the Property contained a Shell Oil Company service station that closed in approximately 1965. No plans showing the former station improvements could be found so ERAS performed a detailed review of historical aerial photographs. The photographs enabled ERAS to determine the location of the former station building, USTs and pump island. With this information, ERAS could design an appropriate Phase 2 investigation with borings in the proper location to sample and analyze groundwater samples down-gradient of the areas of most concern.
The Phase 2 investigation included the drilling of three borings down-gradient of the former USTs and pump island. The work was approved by the Marin County Department of Health. Analysis of the groundwater samples indicated high concentrations of petroleum hydrocarbons in the middle boring, while the other two contained much lower concentrations. The report of results were submitted to the Regional Water Board for them to provide direction to Shell Oil Company for additional investigation and remediation as required.
(Client: Hal Moorehead, Grubb & Ellis)