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Pimlico Drive Turnout and Pipeline Project Er:vironurental CJu~cklist During operation of the facilities a potential upset or accident could release hydrofluorosilic acid used in the fluoridation process at the fluoridation building and at the City of Pleasanton's injection vault. As described in the project description, the fluoridation building is designed with secondary containment under the chemical tank so that in the unlikely event that an upset or accident were to occur, any release is contained onsite. Injection of the hydrofluorosilic acid into the transmission pipeline at the City of Pleasanton injection vault will be remotely monitored as is done at other fluoridation facilities throughout the City and, if there is an accidental release, an alarm is sent to the City's operations control center and personnel are sent out immediately to inspect the facility and take corrective actions as necessary. Accidental release of chemicals during filling of the chemical tank could occur. The chemical is delivered by a commercial company, and the tank is filled to 450 gallons per the City's direction providing a 50 gallon freeboard to minimize potential for spills during filling personal communication Dan Smith, Utilities Superintendent, City of Pleasanton, April 19, 2006). In addition, all handling procedures and traffic routes to the fluoridation building will be approved by the Livermore Pleasanton Fire Department as are operations at all fluoridation facilities throughout the City. Therefore, a) and b) would be less than significant impacts. c) Less than Significant Uses allowed in residential and commercial development adjacent to the project facilities are not associated with substantial use, storage, or transportation of hazardous substances. A private day care school is located within one- quarter mile of the pipeline alignment south of the intersection of Pimlico Drive and Brockton Drive on Brockton Drive. However, the pipeline will only transmit potable water, and there are no hazardous substances that would pose a risk to this school or proposed schools near this project Therefore, this would be less than significant. d) Less than Significant. The area of the project facilities is not included on the list of hazardous materials sites compiled pursuant to Government Code 65962.5 (Cortese List) A leaking underground storage tank was identified south of the project area during a records search for the project and areas within one-half mile of the project area (EDR 2006). The Santa Rita Shell gas station at 6750 Santa Rita Road is located immediately south of Pimlico Drive (and downgradient of the project pipeline) near the intersection with Santa Rita Road. Groundwater remediation activities involving pumping and treating contaminated groundwater were begun in 2003 and are ongoing under the direction of the Alameda County Department of Environmental Health Leaking Underground Storage Tank (LUST) oversight program. The contamination is limited to the Santa Rita Shell gas station site and adjacent shopping center. Gasoline concentrations are at 50 parts per billion. Groundwater flow in the vicinity of the leaking underground storage tank varies from southwest to southeast and the groundwater level is at about 25 feet below the ground surface (personal communication, Jerry Wickham, Alameda County Department of Environmental Health, Hazardous Materials Specialist and project manager for the remediation project, April 1 I, 2006). 17~e Santa Rita control valve vault is located approximately 650 feet southwest of the underground storage tank and gas station. It is unlikely that during excavation of the Santa Rita valve vault site that groundwater contaminated with hydrocarbons from the City of Pleasanton 33 Wmzler & Kelly Draft Initial Study/Proposed Negative Declaration August 2006 04263501