Precision Metal Products, Inc. Corrective Measures Proposal

Precision Metal Products, Inc. Corrective Measures Proposal

The project involves the installation of a Sub-Slab Depressurization (SSD) system, implementation of a Land Use Covenant {LUC)/deed restrictions to prohibit the use of the property as a residence, hospital, school, daycare, and limit the property use to industrial purposes; the LUC will also prohibit interference with the SSD system, and activities that may disturb the soil at the Precision Metal Products Site (Project Site) without a soil management plan. The cleanup decision document, referred to as a Corrective Measures Proposal (CMP) summarized the evaluation of remedial alternatives and concluded that the selected remedial measures are required to protect human health and the environment. The Department of Toxic Substances Control (DTSC) approved the CMP prepared by Advantage Environmental Consultants, LLC, pursuant to Chapter 6.5, Division 4.5, Sections 25187 and 5200.14 of the Health and Safety Code. Background: The Project Site is located on a 4.67-acre property in an industrial/commercial zoned area in the City of El Cajon and is situated north of Bradley Avenue, south of Gillespie Field and east of North Marshall Avenue. The Project Site has a single-story slab on-grade structure of approximately 92,000 square-feet with the remainder of the property covered with asphalt paving. The Project Site was formerly occupied by Fairchild Camera in the early 1960's until 1968 when it was purchased by PMP. PMP manufactures closed die forged and machined metal products for the medical field and aerospace/defense industries. The manufacturing process includes forging, mechanical milling, welding, chemical milling, and electric discharge machining of metals such as aluminum, titanium, cobalt, chrome, stainless steel and steel alloys. In 2007, HBO Industries purchased the sissets of PMP and currently continues its operation. Hazardous materials used at the facility include acids, petroleum hydrocarbons (primarily hydraulic oil), and chemicals containing various volatile organic compounds (VOCs). Previous Investigations: Previous investigations conducted at the Project Site include sampling and analysis of metals, semi-volatile organic compounds (SVOCs), VOCs, Polychlorinated Biphenyls (PCBs) and Total Petroleum Hydrocarbons (TPHs) in soil and groundwater, and VOCs in soil gas and indoor air. The concentrations of chemicals in soil at the Project Site re limited and will not result in adverse .health risks to on-site workers. The investigation results determined that although contamination does not exceed the acceptable risk nor Regional Screening Level for commercial workers, there exists a potential exposure pathway for indoor air through vapor intrusion of VOCs. The San Diego Regional Water Quality Control Board is the lead agency that will continue to assess groundwater impacts in the project area. Project Activities: Project activities involve implementation of a LUC/deed restrictions and installation of an active SSD system to mitigate potential on-site worker exposure to VOCs vapor intrusion into Indoor air. Indoor air sampling will be performed to evaluate the effectiveness of the SSD system. Although VOCs will be extracted at a rate to concentration ratio below acceptable discharge permit limits, an air emissions permit from the San Diego Air Pollution Control District may be required and will be considered in the remedial design document. The current property owner and DTSC will sign a LUC and record with the San Diego County's Recorder's Office. The LUC will prohibit disturbance of soil and cap/cover and restrict the current and future use of the property to commercial/industrial use only.

San Diego