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b. Free product has been removed to the Free product has not been a concern at the site, and Is not known to maximum extent practicable, may still be present Yes currently exist beneath the site. below the site where the release originated, but does not extend off-site. c. The plume has been stable or decreasing for a Monitoring data from the past five years indicates the dissolved - minimum of five years. Yes phase plume is stable. TPHg concentrations In wells BH -2, BH -3, and BH -16 remain high, however. d. The nearest existing water supply well or The nearest groundwater production well is greater than 2,500 feet surface water body is greater than 1,000 feet from Yes from the site. the defined plume boundary. e. The property owner is willing to accept a land If necessary, this issue will have to be discussed with Tesoro's legal use restriction if the regulatory agency requires a department. land use restriction as a condition of closure. Unknown Class 5 a. The regulatory agency determines, based on The plume meets most of the conditions for closure under Class 3, an analysis of site specific conditions that under including not posing a threat to human health and safety under current current and reasonably anticipated near-term and reasonably anticipated near-term future scenarios. future scenarios, the contaminant plume poses a low threat to human health and safety and to the Yes environment and water quality objectives will be achieved within a reasonable timeframe. 2. Vapor Intrusion to Indoor Air To evaluate If the media -specific criteria for petroleum vapor intrusion to indoor air are considered a low -threat for the vapor -intrusion - to -indoor -air pathway at the site, a site specific soil vapor survey will need to be conducted and the data compared to Scenario 1: Unweathered LNAPL in Groundwater of the LTCCP document. The required characteristics are as follows: The site is a retail gasoline service station and will remain as a gasoline service station for the foreseeable future. It is not anticipated that the site will house residential buildings. A soil vapor survey and health risk assessment conducted In 2013 determine insignificant impacts to workers at the site or nearby residences. 1. The bioaltenuation zone shall be a continuous The groundwater table is approximately 10 feet below ground surface zone that provides a separation of at least 30 feel at the site. LNAPL has not been encountered in groundwater vertically between the LNAPL in groundwater and monitoring wells in recent sampling events. TPHg is dissolved In the foundation of existing or potential buildings. As groundwater up to 3,200 pg/I, based on data collected in April 2017, used in this context, unweathered LNAPL is generally understood to mean petroleum product Yes that has not been subjected to significant volatilization or solubilization, and therefore has not lost a significant portion of its volatile or soluble constituents (e.g., comparable to recently dispensed fuel). 2. Total TPH (TPH-g and TPH-d combined) are In confirmation borings advanced in March 2012, residual TPHg in soil less than 100 mg/kg throughout the entire depth of No was detected up to 2,600 mg/kg at 10 feet bgs in boring CSB -1. the bioaltenuation zone. 3. Direct Contact and Outdoor Air Exposure The maximum concentrations of petroleum The maximum concentrations reported for benzene, ethylbenzene, constituents in soil should be compared to the naphthalene, and PAHs in the 5 and 10 foot samples are below the RWQi commercial and utility worker RW QCB's commercial and utility worker thresholds, as indicated in thresholds, as indicated in Chart 1 , taken from the Table 1 below, taken from the LTCCP. The reported maximum LTCCP to indicate soil will have no significant risk concentrations from soil evaluations after remedial action are: of adversely affecting human health. • The maximum benzene concentration detected in soil was 9.0 mg/kg in soil boring CSB -1-10 collected from 10 feet bgs on 3/16/12 Yes • The maximum ethylbenzene concentration detected in soil was 59 mg/kg in soil boring CSB -1-10 collected from 10 feet bgs on 3/16/12 • Naphthalene concentrations have not been reported/detected at the site • Polyaromatic hydrocarbons (PAHs) concentrations have not been reported/detected at the site