This Phase II ESA was conducted to investigate potential petroleum contamination from two above ground storage tanks and three underground storage tanks located on the property of the former London Psychiatric Hospital. Soil and groundwater samples were collected around the storage tanks and analyzed for petroleum compounds. Elevated levels of benzene were detected in soil samples near one of the underground storage tanks. Additional sampling found petroleum contamination limited to an area of approximately 133 square meters around the underground storage tanks at depths of 6-8 meters. Remediation is recommended to meet environmental standards for potential future residential, institutional or parkland use of the property.