3815_PGSF WMVD Pkg 2_Vol 4-2_03.03.2026_BXWA_Certified

ASPECT CONSULTING PROJECT NO. AS190583A-08  MAY 21, 2025 FINAL 43 conducted during the March 2017 groundwater monitoring event. Water level measurements were also collected in selected wells during 16 other monitoring events between 2012 and 2017, as described in Section 2.4.4.2. Section 6.1 describes the collective analytical data set evaluated to document the current (post-IA) contaminant nature and extent in this RI/FS, which includes data from the Phase 2 ESA, both IAs, RCRA closure, and RI characterization work. Appendix B includes the boring/well construction logs for the collective explorations. Table B-1 in Appendix B includes the collective water level data collected from 2012 through 2017. A discussion of the RI activities is provided in the following sections. 4.1 First Interim Action (2013-2014) In accordance with the Agreed Order, an IA was conducted between August 2013 and May 2014, following mill demolition activities. The IA represented a proactive early cleanup of contaminated soils identified from the Upland Area Phase 2 ESA and RI sampling and analysis, with the goal of expediting the overall Upland Area cleanup process. The IA did not conflict with or eliminate reasonable alternatives for the Upland Area final cleanup action in accordance with WAC 173-340-430(3)(b). The IA involved excavation and proper off-Site disposal of contaminated soil with the goal of meeting IA soil cleanup levels (IACLs) to the maximum extent practicable. In late September 2013, shortly after the IA excavation program began, K-C contracted to sell the property to a maritime shipbuilding company, with a planned water-dependent industrial redevelopment consistent with City zoning and meeting MTCA requirements to qualify as an industrial property. In light of the anticipated future use as an industrial shipyard with no public access, K-C communicated to Ecology on October 7, 2013, requesting use of industrial-based IACLs, which Ecology agreed to – with the understanding that additional cleanup may be required in these areas (based on unrestricted cleanup levels) if the sale did not go through. From that point forward, the IAs were conducted applying industrial- use IACLs 14. The IA Plan (Aspect, 2012c), which is included as Exhibit C of the Agreed Order, presents the general IA approach. The IA methods and results are detailed in the IA Report (Aspect, 2015a), and are summarized below, followed by a discussion of the IA confirmational groundwater monitoring program. The IA Report is included in Appendix A. 4.1.1 Soil Removal during First Interim Action The IA was conducted in the 15 discrete areas of the Site, which are identified on Figure 2-4. In total, the IA achieved permanent removal of approximately 38,450 tons of contaminated material from the Upland Area (Aspect, 2015a). 14 The soil IACLs identified for industrial use at the K-C site accounted for both human-direct contact and the protection of groundwater beneficial uses (i.e., soil leaching protective of the marine environment).