Removal Action Workplan for the Former Production Plating Facility, Huntington Beach, CA

Removal Action Workplan for the Former Production Plating Facility, Huntington Beach, CA

DTSC approved a Removal Action Workplan (RAW) for the Former Production Plating Facility pursuant to Chapter 6.8 of the California Health and Safety Code. The RAW includes the following activities: 1. The excavation of VOC- and lead-impacted soil from identified areas within and around site building. Approximately 1,800 tons of soil is expected to be generated from excavation of a 3,000 sf area to 12 ft below the ground surface. 2. The excavation will proceed approximately 4 ft below the water table; therefore, the RAW includes over-excavation of saturated soil and groundwater. Once the excavation is complete, to further reduce VOC concentrations in groundwater, groundwater will be pumped for up to 24 hrs, to remove an estimated 10,000 gallons of groundwater. 3. The excavated impacted soil will be transported off-site to a permitted facility. 4. To determine the completeness of the RAW, soil confirmation sampling of the excavation flood and sidewalls will be performed to verify that soil exceeding cleanup objectives has been satisfactory removed. If concentrations of COCs exceeding the Site remedial goals are detected in the confirmation samples, additional excavation will be performed. 5. To determine that the groundwater remediation goals have been achieved, following the 24-hr pumping period, groundwater will be sampled. If groundwater concentrations remain above remedial goals, the groundwater will be sampled. If groundwater concentrations remain above remedial goals, the groundwater will be pumped for an addition 24 hrs and resampled again for confirmation. 6. At the completion of the remedial excavation and confirmation sampling, the excavation will be backfilled with either native materials taken from other areas of the property or from an approved borrow site. The contractor grader is required to meet the standards established for the surrounding development and the excavated area will be returned to grade and to suitable standards of completion. 7. To address naturally occurring methane present in the site area, the future improvements that will be constructed on the site and surrounding parcels will include the installation of a sub-slab methane-mitigation barrier and venting system. Although the over-excavation of soil and groundwater planned as part of the RAW is expected to remedy VOCs to the applicable standards, the methane mitigation system will also serve as additional protection from potential VOC intrusion to future site occupants. The excavation will take less than one month to complete and will be performed concurrent with demolition of the existing site building and grading of the site and surrounding properties to facilitate the planned redevelopment. The sub-slab system will be installed beneath the new multi-family residential building that will occupy the site and surrounding properties.

Huntington Beach

Orange