Reso PC16-23 PC 0116 Reso CEQA - Sandpiper

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Section 4.0— Enilronmental Selling and Discussion oflnnpacts 4.8 HAZARDS AND HAZARDOUS MATERIALS The following discussion is based, in part, upon a Phase I Environmental Site Assessment and a Hazardous Pipeline Memo that were prepared in September 2014 by Cornerstone Earth Group, and an Asbestos Soil Analysis by Forensic Analytical Laboratories. The documents are included as Appendix B, C, and D, respectively. 4.8.1 Existing Setting 4.8.1.1 Overview Hazardous materials encompass a wide range of substances, some of which are naturally -occurring and some of which are man-made. Examples include motor oil and fuel, metals (e.g., lead, mercury, and arsenic), asbestos, pesticides, and herbicides. A substance may be considered hazardous if, due to its chemical and/or physical properties, it poses a substantial hazard when it is improperly treated, stored, transported, disposed, or released into the environment in the event of an accident. Determining if such substances are present on or near project sites is important because exposure to hazardous materials above regulatory thresholds can result in adverse health effects on humans, as well as harm to plants and wildlife. 4.8.1.2 Historical Use A review of available historical aerial photographs and documentation indicate that Sandpiper Elementary School was historically part of the marshland adjacent to San Francisco Bay. Levees were constructed in the general site vicinity by the early 1940s and a Press Wireless Radio Station building was constructed on adjacent property to the south in approximately 1946. Salt evaporation ponds operated in the general vicinity during the 1950s and 1960s. During the mid-1980s, the adjacent radio station building was demolished and fill was placed on-site and in the general vicinity to raise ground surface elevations. Residential neighborhoods were subsequently constructed on adjacent and nearby properties. The site was developed with Sandpiper Elementary School in 1997. 4.8.1.3 Groundwater Soil borings and cone penetration tests completed on the project site as part of the geotechnical investigation encountered groundwater at depths ranging from 4.5 to seven feet below the ground surface (bgs). The groundwater flow direction is expected to be variable and tidally influenced. 4.8.1.4 Ott,.Site Sources of Contamination Chemical Storage and Use Based on a 2014 site reconnaissance by Cornerstone Earth Group, small quantities of cleaning supplies, gasoline, and other potentially toxic substances are stored on the project site for use during typical daily maintenance and upkeep operations at the project site. Two electrical transformers were observed on the site. The transformers were on concrete pads and located within fenced areas. No City of Redwood City 49 Initial Study/Mitigated Negative Declaration Sandpiper Elementary School Facilities Expansion November 2016