VERTEX performed Phase I Environmental Site Assessments (ESAs) and oversaw underground storage tank (UST) removal activities for an 850-acre vineyard and winery property located in Napa County, California. An initial Phase I ESA assessed the property, buildings, and facilities including USTs, aboveground storage tanks (ASTs), water supply wells, water storage cisterns, and maintenance areas. VERTEX oversaw the removal of two 550-gallon USTs used to store gasoline and diesel fuel. Discolored soil observed on the northern and western sidewalls of the excavation was excavated and analyzed. Following removal of the discolored soil, soil samples were collected from each sidewall, two soil samples were collected from the floor of the excavation, and two stockpile samples were collected to document soil conditions. Analysis of the excavation samples did not reveal the presence of total petroleum hydrocarbons (TPH) quantified as gasoline (TPH-g), diesel (TPH-d), volatile organic compounds (VOCs) and oxygenates at concentrations at or above their respective laboratory reporting limits. One stockpile soil sample indicated low levels of TPH-d at concentrations below residential screening levels in effect at the time. Based on this information, this soil was replaced into the excavation and covered with soil exhibiting no detectable concentrations of TPH. VERTEX was informed by the Napa County Planning, Building, and Environmental Services that they had no requirements to remove or close USTs on agricultural properties. VERTEX prepared subsequent Phase I ESAs which identified residual contamination associated with the former USTs a de minimis condition. No Recognized Environmental Conditions were identified at the site.
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