TA500 - Reservoir Facilities 1514 and 1518 Site TA500 is located near the northern base boundary and includes Facilities 1514, 1515, and 1518 (Reservoir 3). Reservoir 3 is one of three water storage facilities that provides drinking water to Travis AFB. Hydrofluorosilicic acid is used onsite in the fluoridation process. Leaks and spills of hydrofluorosilicic acid occurred, resulting in fluoride in soil and groundwater. In 1992, soil associated with a hydrofluorosilicic acid spill was excavated and disposed of offsite. Based on human health and ecological assessments of the potential risks posed by the fluoride detected in the soil, no action for the soil at this site was selected in the West/Annexes/Basewide Operable Unit Soil Record of Decision. Investigation of the nature and extent of fluoride contamination in groundwater was performed in 2009 and 2015. These data will be used to support selection of a groundwater remedy. Groundwater monitoring is ongoing.