Acronyms and Abbreviations... v. 1.0 Introduction Chemical Use Areas, Chemical Use Area Clusters, and Corrective Measures Study Areas...

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2 Contents Section Page Acronyms and Abbreviations... v 1.0 Introduction Chemical Use Areas, Chemical Use Area Clusters, and Corrective Measures Study Areas Comprehensive Data Quality Objectives Evaluation Unaffiliated Areas CUA Confirmation and Conditional NFA Area Documentation Unaffiliated Areas Media specific DQO Evaluation Response to DTSC Comments on Draft RFI Reports Sampling and Analysis Plan Sampling and Analysis Plan Schedule References... 4 Appendices A B C Tables Unaffiliated Areas Comprehensive Data Quality Objectives Evaluation Responses to DTSC Comments Relevant to the Unaffiliated Areas Unaffiliated Areas Data Gap Sampling and Analysis Plan 1a Current Status of DQO Evaluation for Unaffiliated Areas Soil, Sediment, Soil Vapor, and Surface Water 1b Data Summary Table for Exceedances for Detected Results 1c Data Summary Table for Exceedances for Nondetect Results 2 Summary of Proposed Samples by Matrix within the Unaffiliated Areas 3 Schedule for Unaffiliated Areas Data Gap Work Plan Activities Figures 1 Boeing RFI Subareas for Data Gap Categorization 2 Boeing Subarea 5/9 South Unaffiliated Areas SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC. iii

3 Acronyms and Abbreviations Boeing CMS CNFA CUA DQO DTSC mg/kg MRL NASA RBSL RCRA RFI RI SAP SCL SMOU SSFL SVCL Unaffiliated Areas The Boeing Company corrective measures study conditional no further action chemical use area data quality objectives California Environmental Protection Agency, Department of Toxic Substances Control milligrams per kilogram method reporting limit National Aeronautics and Space Administration risk based screening level Resource Conservation and Recovery Act RCRA facility investigation remedial investigation sampling and analysis plan soil characterization level Surficial Media Operable Unit Santa Susana Field Laboratory soil vapor characterization level Subarea 5/9 South Areas Unaffiliated with RFI sites SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC. v

4 Addendum to Master RCRA Facility Investigation Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California 1.0 Introduction This addendum to the Master Resource Conservation and Recovery Act Facility Investigation Data Gap Work Plan, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California (Master RFI Data Gap Work Plan) was prepared for The Boeing Company (Boeing) (CH2M HILL, 2013a) and relates to the areas within Boeing RFI Subarea 5/9 South that are unaffiliated with any Resource Conservation and Recovery Act (RCRA) facility investigation (RFI) site in Boeing RFI Subarea 5/9 South at the Santa Susana Field Laboratory (SSFL). The Areas Unaffiliated with RFI Sites within Boeing RFI Subarea 5/9 South (Unaffiliated Areas) consist of open space located outside the RFI site buffer boundaries within Boeing RFI Subarea 5/9 South. As presented in Figures 1 and 2, Boeing RFI Subarea 5/9 South includes: The eastern portion of Group 5 located in Administrative Area III (includes the Systems Test Laboratory IV RFI site, Area III Sewage Treatment Plant RFI site, Compound A RFI site, and the southeast portion of the Environmental Effects Laboratory RFI site). The southern portion of Group 9 located between Administrative Areas II and IV and south of Administrative Areas II, III, and IV. Separate addenda to the Master RFI Data Gap Work Plan address the remaining portions of Boeing RFI Subarea 5/9 South. The Master RFI Data Gap Work Plan presents the overall framework and procedures to complete characterization of the nature and extent of contamination and to obtain necessary data to support corrective measures study (CMS) and conditional no further action (CNFA) recommendations 1 for all portions of SSFL that are not subject to either the December 6, 2010 United States Department of Energy Administrative Order on Consent for Remedial Action or the December 6, 2010 National Aeronautics and Space Administration (NASA) Administrative Order on Consent for Remedial Action. The purpose of this addendum to the Boeing Master RFI Data Gap Work Plan is to: Summarize the site characterization within the Unaffiliated Areas that has been completed to date. Document the comprehensive data quality objective (DQO) evaluation for the Unaffiliated Areas (in Appendix A). Respond to California Environmental Protection Agency, Department of Toxic Substances Control (DTSC) comments, when received (in Appendix B). Present the proposed data gap work plan for the Unaffiliated Areas, which presents the plan for addressing data gaps, if any, identified through the DQO evaluation process (in Appendix C). 2.0 Chemical Use Areas, Chemical Use Area Clusters, and Corrective Measures Study Areas To date, no chemical use areas (CUAs), CUA clusters, or CMS areas have been identified within the Unaffiliated Areas. All sampling locations within the Unaffiliated Areas were compared to the most recent soil characterization 1 A CNFA recommendation is based on current site information and weight-of-evidence documentation but is considered conditional pending resolution of Senate Bill 990, findings from future building demolition, and determination of background concentrations, analytical method reporting limits (MRLs), and final regulatory requirements. SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

5 ADDENDUM TO MASTER RCRA FACILITY INVESTIGATION DATA GAP WORK PLAN, BOEING RFI SUBAREA 5/9 SOUTH, AREAS UNAFFILIATED WITH RFI SITES, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA levels 2 (SCLs) and soil vapor characterization levels (SVCLs). Table 1a presents a summary of the nature and extent of contamination and the contaminant fate and transport evaluations that have been performed to date within the Unaffiliated Areas. Tables 1b and 1c present summaries of exceedances for detected and non detect results, respectively, within the Unaffiliated Areas. Two sampling locations (CABS0514 and CABS0515) are associated with the NASA Coca RFI Site but are within the Unaffiliated Areas. Since the Coca area is being investigated by NASA, it is not assessed further in this Work Plan. The portion of the Unaffiliated Areas that is currently being investigated by NASA is shown on Figure 2. Because CUAs, CUA clusters, or CMS areas have not been identified within the Unaffiliated Areas, media specific DQO evaluations are not applicable. 3.0 Comprehensive Data Quality Objectives Evaluation Data gaps for the Unaffiliated Areas were identified by evaluating the DQOs identified in Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California (DQO Report) (CH2M HILL, 2013b) relative to the data and information specific to the Unaffiliated Areas. The data gaps that were identified within the Unaffiliated Areas through this process are presented in Appendix A. 3.1 Unaffiliated Areas CUA Confirmation and Conditional NFA Area Documentation In accordance with the DQO Report (CH2M HILL, 2013b) and the Master RFI Data Gap Work Plan (CH2M HILL, 2013a), Appendix A to this document includes Tables A 1 and A 2, which contain the CNFA Area Weight of Evidence Documentation for the Surficial Media Operable Unit (SMOU) and the CUA Confirmation Status for newly identified features within the Unaffiliated Areas. Table A 1 presents a comprehensive summary of the weight of evidence assessment of any potential release of any chemical within the Unaffiliated Areas for each of the activities listed in DQO Report Figure 2. Any potential release that has not already been identified, investigated, and documented in the Group 5 Central Portions of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California (Group 5 RFI Report) (CH2M HILL, 2008) or in the Draft Group 9 Remedial Investigation Report (Group 9 RI Report) (NASA, 2009) is identified in Table A 1 (highlighted yellow in Table A 1) and carried forward into Table A 2. The information presented in Table A 1 for portions of the Unaffiliated Areas where a potential release of any chemical is not identified (highlighted magenta in Table A 1) will be used to support a future CNFA recommendation for those portions of the Unaffiliated Areas. Table A 2 presents specific information on the newly identified releases and potential releases within the Unaffiliated Areas and the planned approach for addressing these potential releases. In accordance with DQO Report Figure 2, each new potential release identified in Table A 2 is identified as a potential CUA and is subjected to a screening level investigation in accordance with DQO Report Table 2 (for suspect features). Table A 2 presents the one potential CUA (highlighted yellow in Table A 2) that requires a screening level investigation to determine whether a new release or potential release 3 exists and to determine if the potential CUA should be carried forward as a new CUA and subjected to the media specific DQO evaluation. Appendix A also includes Figure A 1, which presents the locations of the newly identified features and the potential CUA identified within 2 The SCLs used to prepare this work plan are the 2005 background levels, the suburban residential risk-based screening levels (RBSLs) included in the May 2012 Gold Copy hard-drive deliverable, and the low-toxicity-reference-value-based ecological RBSLs for soil included in the May 2012 Gold Copy hard-drive deliverable. The background levels and select RBSLs were updated in 2012 while this work plan was in development. The updated background levels and RBSLs will be used in future evaluations of data gaps for the Unaffiliated Areas in accordance with the comprehensive DQO process. The background levels for aluminum, arsenic, and orthophosphate have changed significantly since Consequently, the most recent background levels for these three chemicals (37,900 milligrams per kilogram [mg/kg], 24.2 mg/kg, and mg/kg, respectively) were considered during the evaluation of soil data gaps. The SVCLs used to prepare this work plan are the residential SVCLs presented in Recommended Approach for Assessing the Vapor Intrusion Pathway, Boeing RFI Project, SSFL (CH2M HILL, 2013c) and the low-toxicity-reference-value-based ecological RBSLs for soil vapor included in the May 2012 Gold Copy hard-drive deliverable (CH2M HILL, 2012). 3 A new release or potential release is one that has not already been identified, investigated, and documented in the Group 5 RFI Report (CH2M HILL, 2008) or in the Group 9 RI Report (NASA, 2009). A new release or potential release can result in identification of a new CUA or can represent a new source and/or new chemical(s) associated with an existing CUA. 2 SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

6 ADDENDUM TO MASTER RCRA FACILITY INVESTIGATION DATA GAP WORK PLAN, BOEING RFI SUBAREA 5/9 SOUTH, AREAS UNAFFILIATED WITH RFI SITES, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA the Unaffiliated Areas. Proposed samples to investigate the newly identified release or potential release are identified in Table C 1, Unaffiliated Areas Data Gap Sampling and Analysis in Appendix C. 3.2 Unaffiliated Areas Media-specific DQO Evaluation Based on the approach presented in the DQO Report (CH2M HILL, 2013b), the media specific DQO evaluation is conducted for each new and existing CUA, which are grouped into CUA clusters based on similarities in geographic proximity, operational history, analytical parameters, and related factors. The CUA clusters are then subject to the media specific DQO process for surface water, soil and sediment, vadose zone, and groundwater and seeps. As described in Section 2.0, no CUAs or CUA clusters have been identified within the Unaffiliated Areas. Therefore, the media specific DQO evaluation is not required at this time. As described in Section 3.1, one potential CUA has been identified in the Unaffiliated Areas that requires a screening level investigation. The outcome of the screening level investigation will help determine if the potential CUA should be identified as a new CUA. If a new CUA is identified, media specific DQO evaluations will then be performed. It is also important to recognize that there may be media impacts in the Unaffiliated Areas that are associated with CUA clusters in adjacent or nearby RFI sites. These impacts may include contaminant transport (e.g., air, surface water, groundwater, vapor intrusion) from the RFI site into the Unaffiliated Areas. Per the DQO process, the nature, extent, fate, and transport of contaminants are evaluated for the RFI site where the source is located. This evaluation may result in the identification of CMS areas that extend from the RFI site into the Unaffiliated Areas, or will provide further evidence supporting CNFA for the Unaffiliated Areas. 4.0 Response to DTSC Comments on Draft RFI Reports No comments that were received from the California Environmental Protection Agency, Department of Toxic Substances Control (DTSC) Geological Services Unit on the Group 5 RFI Report (CH2M HILL, 2008; DTSC, 2009, 2010) or the Group 9 RI Report (NASA, 2009; DTSC, 2011a b) pertained directly to the Unaffiliated Areas. Any comments that are received in the future that pertain to the Unaffiliated Areas, along with the corresponding responses to those comments, will be provided in Appendix B. 5.0 Sampling and Analysis Plan This data gap work plan consists of a field SAP to address the RFI analytical data gaps that have been identified for the Unaffiliated Areas. 5.1 Sampling and Analysis Plan The Unaffiliated Areas Data Gap sampling and analysis plan (SAP) to address the data gaps identified in Appendix A is presented in Appendix C. Appendix C includes a table that lists the sample media, sample depth, and analytical groups for each proposed sample (Table C 1) and a table that lists the analytical method proposed for each analytical group (Table C 2). In addition, the rationale and the specific DQOs that the proposed sample are intended to satisfy are identified in Table C 1 for each sample. Figure C 1 in Appendix C presents the locations of the proposed samples. A summary of the samples proposed for collection within the Unaffiliated Areas is presented in Table Schedule The schedule for implementing the Unaffiliated Areas Data Gap Work Plan is presented in Table 3. The table also presents the activities and associated performance periods that are anticipated to collect all data necessary to support the final CMS area and NFA area conclusions for the Unaffiliated Areas. SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

7 ADDENDUM TO MASTER RCRA FACILITY INVESTIGATION DATA GAP WORK PLAN, BOEING RFI SUBAREA 5/9 SOUTH, AREAS UNAFFILIATED WITH RFI SITES, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA 7.0 References CH2M HILL Group 5 Central Portions of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California. November. CH2M HILL Site wide Debris Removal and Documentation Summary, Santa Susana Field Laboratory, Ventura County, California. October. CH2M HILL SSFL Sitewide Gold Copy GIS Mapping and Analytical Geodatabase System (hard drive deliverable). May. CH2M HILL. 2013a. Master Resource Conservation and Recovery Act Facility Investigation Work Plan. March. CH2M HILL. 2013b. Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California. March. CH2M HILL. 2013c. Recommended Approach for Assessing the Vapor Intrusion Pathway, Boeing RCRA Facility Investigation Project, Santa Susana Field Laboratory. March. (Appendix A to DQO Report). California Environmental Protection Agency, Department of Toxic Substances Control (DTSC) Memorandum from Laura Rainey/DTSC to Gerard Abrams/DTSC. Comments on Group 5 Central Portion of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California. December 9. California Environmental Protection Agency, Department of Toxic Substances Control (DTSC) Memorandum from Thomas M. Seckington/DTSC to Gerard Abrams/DTSC. Group 5 RFI Report. January 25. California Environmental Protection Agency, Department of Toxic Substances Control (DTSC). 2011a. Memorandum from Mark Malinowski/DTSC to Allen Elliott/NASA. DTSC Comments on Group 9 Remedial Investigation Report, Santa Susana Field Laboratory, Ventura County, CA. March 30. California Environmental Protection Agency, Department of Toxic Substances Control (DTSC). 2011b. Memorandum from Mark Malinowski/DTSC to Randy Ueshiro/Boeing. DTSC Comments on Group 9 Remedial Investigation Report, Santa Susana Field Laboratory, Ventura County, CA. March 30. Montgomery Watson Harza International (MWH) Site Wide Groundwater Remedial Investigation Report. National Aeronautics and Space Administration (NASA) Draft Group 9 Remedial Investigation Report. November. 4 SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

8 Tables

9 TABLE 1A Current Status of DQO Evaluation for Unaffiliated Areas Soil, Sediment, Soil Vapor, and Surface Water Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California Are all releases and potential releases of chemicals in the Unaffiliated Areas identified in soil, sediment, soil vapor, and surface water? a Releases, Potential Releases, and Physical Characteristics Potential Chemicals Used/Stored Are the nature and extent of chemical distributions characterized to required characterization levels within Unaffiliated Areas? b Based on concentrations detected in soil, sediment, soil vapor, and surface water, do the Unaffiliated Areas meet the criteria for a CNFA recommendation? Subarea 5/9 South Unaffiliated Areas Yes. A summary of the releases, potential releases, and physical characteristics based on currently available information is provided below. The Unaffiliated Areas consist of open space located outside the RFI site buffer boundaries within Boeing RFI Subarea 5/9 South. There are no CUAs located within the Unaffiliated Areas. There is one potential CUA (A) within the Unaffiliated Areas. Potential CUA A is located near the western boundary of Boeing RFI Subarea 5/9 South. Potential CUA A includes two vegetation clearance areas that were identified during the 2010/2011 aerial photograph review. There are no structures present within the Unaffiliated Areas. The depth to bedrock varies throughout the Unaffiliated Areas but is approximately 5 feet bgs in the north and approximately 10 feet bgs in the south and east. Surface water runoff from Administrative Areas II, III, and IV drains through the Boeing RFI Subarea 5/9 South Unaffiliated Areas to Boeing RFI Subarea 10 (north to south). Surface water in the eastern portion of the Unaffiliated Areas drains to the west, while the surface water in the western portion of the Unaffiliated Areas drains to the east into a central drainage feature. The central drainage feature flows to the south into Boeing RFI Subarea 10. VOCs SVOCs No. As described in Table A 2 in Appendix A and as detailed in Appendix C, additional soil and soil vapor sampling is proposed to evaluate newly identified features and elevated MRLs. A summary of the nature and extent of VOCs in soil and soil vapor based on currently available information is presented below. Refer to Tables 1b and 1c for details on the detect results and nondetect results, respectively, that exceed SCLs and SVCLs. Soil Matrix: Three samples were collected from three locations from 0 to 1 foot bgs between 1995 and 1998; VOCs were not detected. Soil Vapor: No soil vapor samples have been collected. No. As described in Tables A 2 in Appendix A and as detailed in Appendix C, additional soil sampling is proposed to evaluate newly identified features and elevated MRLs. A summary of the nature and extent of SVOCs in soil based on currently available information is presented below. Refer to Tables 1b and 1c for details on the detect results and nondetect results, receptively. Soil: Three samples were collected from three locations from 0 to 1 foot bgs between 1995 and 1998 and were analyzed for SVOCs; SVOCs were detected in two of these samples at concentrations below the SCLs. TBD. To be completed after the Subarea 5/9 South Unaffiliated Areas data gap work plan implementation and data evaluation. Additional data are required at Potential CUA A to assess if the vegetation clearance areas should be carried forward as a CUA, or if they meet the criteria for CNFA. TPH PCBs Metals and Inorganics No. As described in Tables A 2 in Appendix A and as detailed in Appendix C, additional soil sampling is proposed to evaluate newly identified features. A summary of the nature and extent of TPHs in soil based on currently available information is presented below. Soil: One sample was collected from 0 to 1 foot bgs in 1998 and analyzed for TPH; TPH was not detected. SCLs have not been developed for TPH. No. Based on the available data for PCBs in soil, additional soil sampling is proposed to address elevated MRLs. A summary of the nature and extent of PCBs in soil based on currently available information is below. Soil: One sample was collected from one location at a ground surface in 1998 and was analyzed for PCBs; PCBs were not detected. No. As presented in Table A 2 in Appendix A and as detailed in Appendix C, additional soil sampling is proposed to evaluate newly identified features and elevated MRLs. A summary of the nature and extent of metals and inorganics in soil based on currently available information is below. Refer to Tables 1b and 1c for details on the detect results and nondetect results, respectively. Soil: Five samples were collected from three locations from 0 to 1 foot bgs between 1995 and 2005 and were analyzed for metals; metals were not detected at concentrations above their SCL. Three samples were collected from three locations from 0 to 1 foot bgs between 1998 and 2005 and were analyzed for inorganics; inorganics were not detected above SCLs. Dioxins and furans Yes. Based on the available data for dioxins and furans in soil, no further characterization of dioxins and furans is required. A summary of the nature and extent of dioxins and furans in soil based on currently available information is provided below. Refer to Tables 1b and 1c for details on the detect results and nondetect results, respectively. Soil: Three samples were collected from three locations from 0 feet bgs in 1995 and 1998 and were analyzed for dioxins and furans. Dioxins and furans were not detected at concentrations that were greater than the SCLs. Energetics No. Based on the available data for energetics in soil, additional soil sampling is proposed to address elevated MRLs. A summary of the nature and extent of energetics in soil based on currently available information is below. Soil: One sample was collected from one location at 0 feet bgs in 1998 and was analyzed for energetics; energetics were not detected. Notes: This table only applies to those portions of the Boeing RFI Subarea 5/9 South outside the area being addressed by NASA, shown on Figure 2. a The questions presented in this table are modified from the questions presented in other Work Plan addenda for Boeing RFI sites on the basis that no CUAs have been identified in the Unaffiliated Areas. Fate and transport, risk assessment, and remedial planning evaluations are not warranted for areas that do not have CUAs. b Only primary samples are counted for purposes of calculating the number of samples, number of detections, or number of detections that exceed characterization levels in this table (duplicate and split samples are not counted as separate samples). Conversely, all analytical results for primary, duplicate, and split samples that exceed characterization levels are shown in Tables 1b and 1c for detect and non detect results, respectively. Acronyms: bgs = below ground surface CUA = chemical use area SCL = soil characterization limit TPH = total petroleum hydrocarbons CMS = corrective measures study PCB = polychlorinated biphenyl SVCL = soil vapor characterization limit VOC = volatile organic compound CNFA = conditional no further action RFI = RCRA facility investigation SVOC = semivolatile organic compound SFO\ PAGE 1 OF 1 ES BAO

10 TABLE 1b Data Summary Table for Exceedances for Detected Results No CC Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California CUA Cluster No CC No CC No CC No CC No CC No CC No CC Stats Chem > Characterization Level # samples analyzed # samples detected Excavation Status VOCs - Soil (ug/kg) - None detected SVOCs - Soil (ug/kg) - No exceedances for detected results PCBs - Soil (ug/kg) - None detected Energetics - Soil (ug/kg) - None detected Dioxin_Furans - Soil (pg/g) - No exceedances for detected results Metals - Soil (mg/kg) - No exceedances for detected results Inorganics - Soil (mg/kg) - None detected Collection Date Residential Characterization Level Comparisons 1 Sample ID for detects > Res RBSL Concentration Ratio to Res RBSL Bottom Depth (ft bgs) Ecologic Characterization Level Comparisons 2 Ecological CMS Level Comparisons 2 Ratio to Bottom Ratio to Sample ID for detects > Sample ID for detects > Concentration Eco Low Depth (ft Concentration Eco High Eco Low RBSL Eco High RBSL RBSL bgs) RBSL 1 For Residential and Ecological screening, chemicals with a DTSC-approved background value undergo a two-tiered screening. Each result is first screened against the background threshold value (BTV) to identify data potentially related to site operations, and then those data are compared to RBSLs. The ratio is calculated as the data result divided by the RBSL. 2 Low and High Ecological RBSLs are used for data comparison. Low ecological comparisons are based on low toxicity reference value (TRV) RBSLs and are used for data gap analysis and sampling recommendations; high ecological comparisons are based on high TRV RBSLs and are used in conjunction with other lines of evidence for CMS and remedial planning recommendations Bottom Depth (ft bgs) Acronyms: µg/kg = micrograms per kilogram BTV = background threshold value CC = CUA cluster CUA = chemical use area ft bgs = feet below ground surface mg/kg = milligrams per kilogram MRL = method reporting limit PCB = polychlorinated biphenyl RBSL = risk based screening level SVOC = semivolatile organic compound VOC = volatile organic compound No CC Detects Page 1 of 5

11 TABLE 1c Data Summary Table for Exceedances for Non Detect Results No CC Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California CUA Cluster No CC No CC No CC Chem w/ Result > Characterization Level VOCs - Soil (ug/kg) # samples analyzed # samples not detected Detected? Detected > RBSLs? 2 Chloroethylvinyl ether 1 1 FALSE FALSE SVOCs - Soil (ug/kg) Stats Benzo(a)pyrene 3 3 FALSE FALSE Dibenzo(a,h)anthracene 3 3 FALSE FALSE Hexachlorobutadiene 3 3 FALSE FALSE Di-n-butyl phthalate 3 1 TRUE FALSE Acenaphthylene 3 3 FALSE FALSE bis(2-ethylhexyl) phthalate 3 1 TRUE FALSE PCBs - Soil (ug/kg) Aroclor FALSE FALSE Aroclor FALSE FALSE Aroclor FALSE FALSE Aroclor FALSE FALSE Excavation Status Collection Date Residential Characterization Level Comparisons 1 Sample ID for MRL > Res RBSL MRL Ratio to Res RBSL Bottom Depth (ft bgs) # Samples > Res RBSL Res RBSL BTV In Place 6/15/1998 BCSS10S Ecologic Characterization Level Comparisons 2 Ecological CMS Level Comparisons 2 Ratio to Bottom Ratio to Sample ID for MRL > Sample ID for MRL > MRL Eco Low Depth (ft MRL Eco High Eco Low RBSL Eco High RBSL RBSL bgs) RBSL # Samples > Res RBSL Res RBSL BTV In Place 6/15/1998 BCSS10S In Place 7/25/1995 BKND In Place 7/25/1995 BKND # Samples > Res RBSL Res RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low Eco Low # Samples > Eco High Eco High RBSL RBSL BTV RBSL RBSL BTV In Place 6/15/1998 BCSS10S BCSS10S In Place 7/25/1995 BKND BKND In Place 7/25/1995 BKND BKND # Samples > Eco Low Eco Low RBSL RBSL BTV In Place 6/15/1998 BCSS10S In Place 6/15/1998 BCSS10S # Samples > Eco Low Eco Low RBSL RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low Eco Low RBSL RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low RBSL Eco Low RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low Eco Low RBSL RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low Eco Low # Samples > Eco High Eco High RBSL RBSL BTV RBSL RBSL BTV In Place 6/15/1998 BCSS10S BCSS10S # Samples > Eco Low Eco Low RBSL RBSL BTV In Place 6/15/1998 BCSS10S Bottom Depth (ft bgs) No CC Non-detects Page 2 of 5

12 TABLE 1c Data Summary Table for Exceedances for Non Detect Results No CC Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California CUA Cluster No CC No CC No CC No CC Chem w/ Result > Characterization Level Stats # samples analyzed # samples not detected Detected? Detected > RBSLs? Aroclor FALSE FALSE Energetics - Soil (ug/kg) 2-Amino-4,6-Dinitrotoluene 1 1 FALSE FALSE RDX 1 1 FALSE FALSE Dioxin_Furans - Soil (pg/g) - No exceedances for non-detected results Metals - Soil (mg/kg) Thallium 5 5 FALSE FALSE Mercury 3 3 FALSE FALSE Selenium 3 3 FALSE FALSE Antimony 3 3 FALSE FALSE Boron 3 1 TRUE FALSE Molybdenum 3 1 TRUE FALSE Inorganics - Soil (mg/kg) - No exceedances for non-detected results Excavation Status Collection Date Residential Characterization Level Comparisons 1 Sample ID for MRL > Res RBSL MRL Ratio to Res RBSL Bottom Depth (ft bgs) Ecologic Characterization Level Comparisons 2 Ecological CMS Level Comparisons 2 Ratio to Bottom Ratio to Sample ID for MRL > Sample ID for MRL > MRL Eco Low Depth (ft MRL Eco High Eco Low RBSL Eco High RBSL RBSL bgs) RBSL # Samples > Eco Low Eco Low RBSL RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low RBSL Eco Low RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low Eco Low # Samples > Eco High Eco High RBSL RBSL BTV RBSL RBSL BTV In Place 6/15/1998 BCSS10S BCSS10S # Samples > Res RBSL and BTV Res RBSL BTV # Samples > Eco Low RBSL and BTV Eco Low RBSL BTV In Place 6/15/1998 BCSS10S BCSS10S In Place 7/25/1995 BKND BKND In Place 7/25/1995 BKND # Samples > Eco Low Eco Low RBSL and BTV RBSL BTV In Place 6/15/1998 BCSS10S In Place 7/25/1995 BKND In Place 7/25/1995 BKND # Samples > Eco Low Eco Low # Samples > Eco High Eco High RBSL and BTV RBSL BTV RBSL and BTV RBSL BTV In Place 6/15/1998 BCSS10S BCSS10S In Place 7/25/1995 BKND BKND In Place 7/25/1995 BKND BKND # Samples > Eco Low Eco Low # Samples > Eco High Eco High RBSL and BTV RBSL BTV RBSL and BTV RBSL BTV In Place 6/15/1998 BCSS10S BCSS10S # Samples > Eco Low Eco Low RBSL and BTV RBSL BTV In Place 6/15/1998 BCSS10S # Samples > Eco Low Eco Low # Samples > Eco High Eco High RBSL and BTV RBSL BTV RBSL and BTV RBSL BTV In Place 6/15/1998 BCSS10S BCSS10S For Residential and Ecological screening, chemicals with a DTSC-approved background value undergo a two-tiered screening. Each result is first screened against the background threshold value (BTV) to identify data potentially related to site operations, and then those data are compared to RBSLs. The ratio is calculated as the data result divided by the RBSL. 2 Low and High Ecological RBSLs are used for data comparison. Low ecological comparisons are based on low toxicity reference value (TRV) RBSLs and are used for data gap analysis and sampling recommendations; high ecological comparisons are based on high TRV RBSLs and are used in conjunction with other lines of evidence for CMS and remedial planning recommendations Bottom Depth (ft bgs) No CC Non-detects Page 3 of 5

13 TABLE 1c Data Summary Table for Exceedances for Non Detect Results No CC Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California CUA Cluster Chem w/ Result > Characterization Level Acronyms: µg/kg = micrograms per kilogram BTV = background threshold value CC = CUA cluster CUA = chemical use area ft bgs = feet below ground surface mg/kg = milligrams per kilogram MRL = method reporting limit PCB = polychlorinated biphenyl RBSL = risk based screening level SO = soil SVOC = semivolatile organic compound VOC = volatile organic compound Stats # samples analyzed # samples not detected Detected? Detected > RBSLs? Excavation Status Collection Date Residential Characterization Level Comparisons 1 Sample ID for MRL > Res RBSL MRL Ratio to Res RBSL Bottom Depth (ft bgs) Ecologic Characterization Level Comparisons 2 Ecological CMS Level Comparisons 2 Ratio to Bottom Ratio to Sample ID for MRL > Sample ID for MRL > MRL Eco Low Depth (ft MRL Eco High Eco Low RBSL Eco High RBSL RBSL bgs) RBSL Bottom Depth (ft bgs) No CC Non-detects Page 4 of 5

14 General Notes for Tables 1b and 1c: This table only lists chemicals for which a characterization level exists. The soil characterization levels used in preparing these summary tables are the 2005 background levels, the suburban residential RBSLs included in the May 2012 Gold Copy hard drive deliverable, and the low toxicity reference value based ecological RBSLs for soil included in the May 2012 Gold Copy hard drive deliverable. The background levels and select RBSLs were updated in 2012 while this work plan was in development. The updated background levels and RBSLs will be used in future evaluations of data gaps for the STL IV RFI site, in accordance with the comprehensive DQO process. The background levels for aluminum, arsenic, and orthophosphate have changed significantly since Consequently, the most recent background levels for these three chemicals (37,900, 24.2, and milligrams per kilogram, respectively) were considered during the evaluation of soil data gaps. The SVCLs used in preparing this work plan are the residential SVCLs presented in Recommended Approach for Assessing the Vapor Intrusion Pathway, Boeing RFI Project, SSFL (CH2M HILL, 2013c) and the low toxicity reference value based ecological RBSLs for soil vapor included in the May 2012 Gold Copy hard drive deliverable. Chemicals listed as VOC in Vapor Screens represent the total VOCs concentration measured using a field screening method. For non detect results, chemical characterization levels are compared against the practical quantification limits (PQL) as the method reporting limits. If PQL values were not available, the method detection limits were used for the comparisons. SO = Soil

15 TABLE 2 Summary of Proposed Samples by Matrix for the Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California RFI Site No. Soil Samples (including samples on hold) No. Soil Vapor Samples No. Rock Samples No. Groundwater Samples Total No. Proposed Samples Unaffiliated Areas SFO\ PAGE 1 OF 1 ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

16 TABLE 3 Schedule for Unaffiliated Areas Data Gap Work Plan Activities Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California Activity Submittal of Addendum for Unaffiliated Areas March 2013 DTSC Review/Comment on Draft Master RFI Data Gap Work Plan Addendum for Boeing RFI Subarea 5/9 South Unaffiliated Areas Boeing revises Draft Master RFI Data Gap Work Plan Addendum for Boeing RFI Subarea 5/9 South Unaffiliated Areas in response to DTSC comments Conduct Public Meeting for Draft Master RFI Data Gap Work Plan Addendum for Boeing RFI Subarea 5/9 South Unaffiliated Areas Boeing prepares Final Master RFI Data Gap Work Plan Addendum for Boeing RFI Subarea 5/9 South Unaffiliated Areas and submit to DTSC for final review/approval DTSC approves Final Master RFI Data Gap Work Plan Addendum for Boeing RFI Subarea 5/9 South Unaffiliated Areas Boeing RFI Subarea 5/9 South Unaffiliated Areas Data Gap Work Plan Implementation Field Work and Data Validation Boeing prepares Draft Boeing RFI Subarea 5/9 South Data Summary and Findings Report; submits to DTSC for review Estimated Performance Period April 2013 April 2013 May 2013 May 2013 June 2013 June 2013 December 2013 a November 2013 April 2014 Notes: a Boeing will confer with DTSC during this period to verify that all outstanding data gaps have been identified and filled and to verify that all DQOs have been achieved. SFO\ PAGE 1 OF 1 ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

17 Figures

18 VICINITY MAP UNDEVELOPED LAND NASA UNDEVELOPED LAND AREA III AREA II AREA I AREA IV UNDEVELOPED LAND UNDEVELOPED LAND UNDEVELOPED LAND AREA IV EEL STP-3 Compound A STL-IV ECL AREA III Boeing RFI Subarea 5/9 North Silvernale AREA II Boeing RFI Subarea 1B North CTL-V CTL-III R-1 Pond LF AREA I Bowl Area A1 AF APTF Impoundment 1 CN Boeing RFI Group 1A North HVN BS IL HVS B1 Boeing RFI Group 1A South Boeing RFI Subarea 1A South Boeing RFI Subarea 1A North Boeing RFI Subarea 1A Central LEGEND DOE AOC Boundary NASA AOC Boundary RFI Group Boundary Administrative Boundary Ponds Boeing RFI Site Paved Road Dirt Road Unpaved trail Boeing RFI Subarea 5/9 South Area I Burn Pit Boeing RFI Subarea 1B Southwest Perimeter Pond Boeing RFI Subarea 1B Southeast UNDEVELOPED LAND Boeing RFI Subarea 10 $ ,500 Feet 1 in = 1,500 ft FIGURE 1 Boeing RFI Subareas for Data Gap Characterization Addendum to Master RFI Data Gap Work Plan Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California SCO K:\BOEING\362070\MAPFILES\2013\DQO\SUBAREA5_9_SOUTH\REPORTFIGURES\SUB59S_FIGURE1_SUBAREAS.MXD RANHORN 5/17/2013 9:52:32 AM

19 VICINITY MAP UNDEVELOPED LAND NASA UNDEVELOPED LAND AREA III AREA II AREA I AREA IV UNDEVELOPED LAND BASEMAP LEGEND Boeing RFI Site RFI Group Boundary Administrative Boundary Chemical Use Area (CUA) Dirt Road Paved Road Rock Outcrop Pond 1 CUA Reference Number CUA Cluster (CC) Transformer Pad Structure!!!!!!!!!!!!!!! Boeing RFI Subarea 5/9 South Area being investigated by NASA as part of the Coca RFI site Soil CMS Area Soil Vapor CMS Area Features ' Debris Point! Transformer Pole Pipeline Leach Field Line Debris Line Drainage Channel Operational Channel Aboveground Storage Tank Underground Storage Tank Not Yet Determined Storage Yard Debris Area Disturbed Soil Vegetation Clearing Excavation Area U U U U U U U U U U Undefined Feature U U U U U Spray Field Leach Field Area Septic Tank Sumps $ Feet 1 in = 600 ft FIGURE 2 Subarea 5/9 South Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California SCO K:\BOEING\362070\MAPFILES\2013\DQO\SUBAREA5_9_SOUTH\REPORTFIGURES\SUB59S_FIGURE2_UNAFFILIATEDAREAS.MXD RANHORN 5/17/2013 9:46:08 AM

20 Appendix A Unaffiliated Areas Comprehensive DQO Evaluation

21 Appendix A Contents CUA Confirmation and Conditional NFA Area Weight of Evidence Documentation Table A 1: Conditional NFA Weight of Evidence Documentation for the Boeing RFI Subarea 5/9 South Unaffiliated Areas Table A 2: Potential CUA Confirmation and Supplemental Conditional NFA Area Weight of Evidence Documentation for the SMOU, Boeing RFI Subarea 5/9 South Unaffiliated Areas Figure A 1: New Identified Features and Potential CUA within the Boeing RFI Subarea 5/9 South Unaffiliated Areas Figure A 2: Comparison of Analytical Results to Characterization Levels for Soil from 0 to 2 Feet Below Ground Surface, Subarea 5/9 South Unaffiliated Areas Figure A 3: Comparison of Analytical Results to Characterization Levels for Soil from 2 to 10 Feet Below Ground Surface, Subarea 5/9 South Unaffiliated Areas Figure A 4: Comparison of Analytical Results to Characterization Levels for VOCs (Soil and Soil Vapor) from 0 to 10 Feet Below Ground Surface, Subarea 5/9 South Unaffiliated Areas SFO\ A-1 ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

22 TABLE A 1 Conditional No Further Action Weight of Evidence Documentation for the Boeing RFI Subarea 5/9 South, Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California Activities to Support CNFA Area Recommendations for the SMOU a Method 1: Document and Record Review RFA Activity completed and Assessment and documentation supporting recommendation that no release or potential release of any chemical previously used, stored, handled, or disposed was identified within the all relevant information Boeing RFI Subarea 5/9 South Unaffiliated Areas, other than the potential releases identified in Table A 2 and data reviewed? Review of all available historical RCRA Facility Investigation related reports and documents that might contain information relevant to the RFI. RFA ( ) historical and current operational chemical use information was reviewed, a site inspection was performed, and previous sampling data were evaluated to determine the Yes likelihood of a potential release to environmental media. One hundred and twenty five areas of SSFL that used, stored, or handled hazardous waste were identified for designation as SWMUs or AOCs by the USEPA. By definition, no SWMUs or AOCs are located in the Boeing RFI Subarea 5/9 South Unaffiliated Areas. CNFA Weight of Evidence Documentation, Question 1: Was a release or potential release b newly identified? No RFI Program Report Subsequent to the RFA, 10 additional AOCs were identified during the SSFL RFI program report preparation, for a total of 135 SWMUs and AOCs at the entire SSFL. These 135 SWMUs and AOCs were grouped into 51 RFI sites. Boeing, DOE, NASA, and DTSC subdivided the SSFL into 11 RFI groups for the purposes of RFI reporting work activities, each containing 0 to 17 RFI sites. By definition, no SWMUs, AOCs, or RFI sites are located in the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Yes No 2008 Group 5 RFI Report and 2009 Group 9 RI Report and DTSC and Stakeholder Comments on these Reports The 2008 and 2009 RFI reports considered all historical reporting and documentation available at the time of report preparation. Six soil samples have been collected in the Boeing RFI Subarea 5/9 South Unaffiliated Areas between 1995 and No CUAs have been identified for the Boeing RFI Subarea 5/9 South Unaffiliated Areas. DTSC did not provide comments that specifically pertain to the Boeing RFI Subarea 5/9 South Unaffiliated Areas. However, the comments received on other RFI reports were taken into consideration, as appropriate, during the DQO evaluation for the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Yes No Sitewide Groundwater RI Report The sitewide groundwater RI report (2009) presents an assessment of the nature and extent of SSFL site related chemicals in groundwater and the vadose zones bedrock. The groundwater RI report was reviewed to identify information relevant to the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Groundwater well RD 67 is installed within the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Methyl tert butyl ether was detected in RD 67 at concentrations that exceed the MCL. Groundwater inpacted with chlorinated solvents that originate at or near STL IV extend south, into the northern portion of the Unaffiliated Areas. No additional soil investigations are required based on the review of the groundwater RI report (MWH, 2009). Yes No Review of Historic Documentation Review of historical documentation was performed, including but not limited to reports, maps, inventories, spill records, notes, and correspondence to identify areas of chemical use not already identified during the prior RFA or RFI activities. Approximately 70,000 historic documents related to Group 5 and approximatly 20,000 documents related to Group 9 were reviewed for identification of information potentially relevant to the Boeing SSFL RFI, and findings were included in the Group 5 RFI report (CH2M HILL, 2008) and the Group 9 RI report (NASA, 2009). Electronic copies of these historical documents were previously provided to DTSC on external hard drives. Subsequently, additional historical documents that became available were reviewed using the same process to identify RFI relevant information. Electronic copies of these historical documents were provided to DTSC in January The review of historical documentation did not result in the identification of new features beyond those presented in the 2008 and 2009 RFI Reports in the Unaffiliated Areas. No, currently under review TBD Review of historical documents is ongoing. Additional releases or potential releases that may be identified during the review of additional historical documents will be addressed during future evaluations of data gaps for the Boeing RFI Subarea 5/9 South Unaffiliated Areas, in accordance with the comprehensive DQO process. Method 2: Sitewide Inventories Compilation and evaluation of sitewide inventories of infrastructure or features with potential chemical storage, distribution, use, or disposal history Building Inventory and Feature Survey No buildings are known to have existed in the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Not Applicable No Tank Inventory A SSFL sitewide tank inventory was prepared by Boeing, DOE, and NASA. This inventory identifies all known information regarding the location, size, composition, contents, use period, and regulatory status of all underground storage tanks, aboveground storage tanks, and undetermined tanks. No tanks were identified in the Boeing RFI Subarea 5/9 South Unaffiliated Areas during the tank inventory process. The documentation for the entire Boeing SSFL tank inventory was provided with the Central Key Document Repository deliverable to DTSC in April 2011 (and subsequently in May 2012). No other features were identified during the tank inventory compilation that require investigation for the Unaffiliated Areas. Yes No Sewer System Survey The SSFL sitewide sewer system survey was performed in to visually inspect sewer manholes and pipeline inlets and outlets and to identify manholes that are in poor condition and may have resulted in impacts to environmental media. CH2M HILL inspected the 33 sanitary sewer system manholes located in Group 5 in August The manholes were observed to be active and intact in the Boeing RFI Subarea 5/9 South Unaffiliated Areas, and no sediment was observed inside these manholes at the time of the inspection. No fractures or deterioration of the concrete manhole structure, including the inlet and outlet pipelines, was observed. All nearby soil and soil vapor data collected from within 100 feet of the manholes and sewer pipeline located within the reporting area were reviewed. There is no evidence of a release or potential release from the sewer system located within the Boeing RFI Subarea 5/9 South Unaffiliated Areas based on this information. No, currently under review TBD Further evaluation of potential impacts to environmental media resulting from potential releases from the sewer system in the Boeing RFI Subareas is being performed. Recommendations for additional investigation of the sewer system in the Boeing RFI Subareas, if needed, will be presented in a future report. Reclaimed Water System Inventory A comprehensive sitewide evaluation was performed by Boeing, DOE, and NASA to identify and document the locations and operational history of all features associated with the reclaimed water system. The documentation for the Boeing SSFL reclaimed water system was provided with the Central Key Document Repository deliverable to DTSC in May No features were identified in the Boeing RFI Subarea 5/9 South Unaffiliated Areas during the 2010/2011 water conveyance system inventory activities. No, currently under review TBD Further evaluation of potential impacts to environmental media resulting from potential releases from the reclaimed water system in the Boeing RFI Subareas is being performed. Recommendations for additional investigation of the reclaimed water system in the Boeing RFI subareas, if needed, will be presented in a future report. ES BAO PAGE 1 OF 3

23 TABLE A 1 Conditional No Further Action Weight of Evidence Documentation for the Boeing RFI Subarea 5/9 South, Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California Activities to Support CNFA Area Recommendations for the SMOU a Pipelines with Mastic Tape Documentation Assessment and documentation supporting recommendation that no release or potential release of any chemical previously used, stored, handled, or disposed was identified within the Boeing RFI Subarea 5/9 South Unaffiliated Areas, other than the potential releases identified in Table A 2 A comprehensive sitewide evaluation was performed by Boeing, DOE, and NASA to identify and document the locations of natural gas pipelines wrapped with mastic tape (that potentially contains PCBs and/or SVOCs). A summary of the natural gas pipeline system at SSFL was provided with the Central Key Document Repository deliverable to DTSC in May In addition, other pipelines wrapped with mastic tape have been identified elsewhere at SSFL. No natural gas pipelines wrapped with mastic tape have been identified within the Boing RFI Subarea 5/9 South Unaffiliated Areas, as documented in the Natural Gas Pipeline GIS Feature Class Technical Memorandum (MWH, 2012a). In addition, no other types of pipelines wrapped with mastic tape have been identified within the Boing RFI Subarea 5/9 South Unaffiliated Areas. Activity completed and all relevant information and data reviewed? Yes CNFA Weight of Evidence Documentation, Question 1: Was a release or potential release b newly identified? No Primary Fuel oil and Chemical Pipeline inventory A review of available documentation has been performed. No fuel oil or chemical pipelines extending within, to, or from the Boeing RFI Subarea 5/9 South Unaffiliated Areas were identified. Yes No GIS Gold Copy Data Management Tool The GIS Gold Copy Data Management Tool is a comprehensive GIS and analytical database that was compiled for SSFL and contains current and complete Boeing, NASA, and DOE chemical and radiological data for surficial media and groundwater. The GIS Gold Copy Data Management Tool was submitted to DTSC in May This tool was reviewed to identify any features potentially associated with a release to environmental media that are not included in the 2008 Group 5 RFI Report and the 2009 Group 9 RI Report and not identified elsewhere in this table. No other new features potentially associated with a release in the Boeing RFI Subarea 5/9 South Unaffiliated Areas were identified through this process. Yes No Method 3: Sitewide Inspections Debris Survey and Sampling SSFL Sitewide comprehensive inspections and documentation Boeing, DOE, and NASA performed a sitewide debris survey in 2008/2009 to systematically identify surficial evidence of solid waste disposal through visual inspections of the SSFL. The Debris Survey was conducted on 50 foot transects across all of SSFL to document the types and locations of debris. The survey was performed in accordance with the Onsite Debris Survey and Sampling Methodology SOP (CH2M HILL and MWH, 2008). No debris areas were identified in Boeing RFI Subarea 5/9 South Unaffiliated Areas. Yes No Biological Survey and Mapping Aerial Photograph Review A sitewide survey of biological and ecological site conditions was performed in The results of the survey were mapped and included in the Boeing RFI Reports. No conditions were observed in the Boeing RFI Subarea 5/9 South Unaffiliated Areas in 2008 that warrant additional investigation. No further evaluation is recommended for the Boeing RFI Subarea 5/9 South Unaffiliated Areas with respect to the biological survey and mapping. Review of historical aerial photographs was performed, commencing in 1997 (U.S. EPA) and continuing through 2010 (Boeing, DOE, and NASA) to identify areas of chemical use not previously identified. Boeing, DOE, and NASA reviewed historic aerial photographs representing 17 photo coverage years that span the life cycle of SSFL facility operations, from 1953 to Features identified in the aerial photograph review were documented in GIS. The documentation for the entire Boeing SSFL aerial photograph review was provided with the GIS Gold Copy Data Management Tool to DTSC in May New features in the Boeing RFI Subarea 5/9 South Unaffiliated Areas were identified during the aerial photograph review. These new features are listed Table A 2. Aside from the newly identified features listed Table A 2, no other features were identified during the aerial photograph review that require investigation for the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Yes No Yes Yes, see Table A 2 Method 4: Boeing RFI Subarea 5/9 South Unaffiliated Areas Inspections Topography and Physical Accessibility Boeing RFI Subarea 5/9 South Unaffiliated Areas specific inspections and documentation The topography was evaluated to identify areas of the site for which historic chemical use, storage, handling, or disposal activities would have been prohibitively difficult. No areas were identified as being prohibitively difficult to access. Therefore, all portions of the Boeing RFI Subarea 5/9 South Unaffiliated Areas were subject to evaluations regarding the historic use, storage, handling, or disposal of chemicals. Proximity to Roadways and Operations The roadways located within the Boeing RFI Subarea 5/9 South Unaffiliated Areas were evaluated in the context of the Field Sampling Methodologies for CUA or CNFA Determination for the Yes No SMOU (Table 2 of the Comprehensive DQO Report). No roadways were identified as requiring further investigation based on the sampling strategy presented in DQO Report Table 2 for roads. Geophysical Survey A geophysical survey has not been performed in the Boeing RFI Subarea 5/9 South Unaffiliated Areas on the basis that there are no significant underground features (for example, USTs) that Not Applicable Not Applicable have been identified in the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Demolition Documentation and Sampling No demolition activities have been performed in the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Not Applicable Not Applicable Interim Removal Actions No interim removal actions have been performed in the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Not Applicable Not Applicable Method 5: Chemical Migration Assessment Vapor Intrusion Pathway Evaluation Evaluation of potential chemical migration from any CUA to Boeing RFI Subarea 5/9 South Unaffiliated Areas thought to be unimpacted (Group 5/9 South Unaffiliated Areas CNFA areas) The vapor intrusion pathway will be evaluated in accordance with Appendix A of the Comprehensive DQO Report: Recommended Approach for Assessing the Vapor Intrusion Pathway, No, currently under Boeing RCRA Facility Investigation Project (CH2M HILL, 2013a). Additional soil gas data will be collected where required to complete characterization of the nature and extent and fate and review transport of impacts from potential source areas. The areas of the Boeing RFI Subarea 5/9 South Unaffiliated Areas where the vapor intrusion pathway might be complete will be spatially delineated by considering the known or suspected vapor sources, the nature and extent of impacts, and the fate and transport of VOC constituents. Yes No TBD Vadose Zone Mass Flux to Groundwater Modeling Air Deposition Modeling Vadose zone mass flux to groundwater modeling will be performed to identify potential sources of groundwater impacts. The evaluation will be performed in accordance with Appendix D of the Comprehensive DQO Report: Recommended Approach for Evaluating Vadose Zone Mass Flux of Contaminants to Groundwater (MWH, 2012b). The vadose zone mass flux to groundwater approach includes evaluating the need for additional field data (i.e., drilling of deep borings); evaluating the need to model vadose zone mass flux to groundwater; modeling; and determining if the vadose zone should be recommended for the CMS or CNFA. It is not expected the vadose zone mass flux to groundwater modeling will be required for the Boeing RFI Subarea 5/9 South Unaffiliated Areas. Air dispersion modeling is currently being performed for sources identified in Appendix B of the DQO Report: Recommended Approach for Air Dispersion Modeling, Boeing RCRA Facility Investigation Project (CH2M HILL, 2013b). The need to model potential sources and to collect soil samples in impacted and unimpacted areas will be determined after the completion of modeling identified in Recommended Approach for Air Dispersion Modeling, Boeing RCRA Facility Investigation Project (CH2M HILL, 2012b). No, currently under review No, currently under review TBD TBD ES BAO PAGE 2 OF 3

24 TABLE A 1 Conditional No Further Action Weight of Evidence Documentation for the Boeing RFI Subarea 5/9 South, Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California Activities to Support CNFA Area Recommendations for the SMOU a Surface Water Drainage Documentation Assessment and documentation supporting recommendation that no release or potential release of any chemical previously used, stored, handled, or disposed was identified within the Boeing RFI Subarea 5/9 South Unaffiliated Areas, other than the potential releases identified in Table A 2 A comprehensive sitewide evaluation was performed by Boeing, DOE, and NASA to identify and document the locations of all surface water drainage features and the direction of surface water flow at RFI sites. The results of this comprehensive evaluation were included in the GIS Gold Copy Data Management Tool submitted to DTSC in May No new surface water drainages were identified in the Boeing RFI Subarea 5/9 South Unaffiliated Areas through this process. Surface water drainage channels in the Boeing RFI Subarea 5/9 South Unaffiliated Areas have been investigated, the results of which were included in the 2008 Group 5 RFI Report and RI Report. Activity completed and all relevant information and data reviewed? Yes CNFA Weight of Evidence Documentation, Question 1: Was a release or potential release b newly identified? No NPDES Surface Water Data Seeps and Springs Data Analytical Data Collected for Purposes Other than the RFI Surface water runoff at the SSFL is regularly monitored as part of the NPDES monitoring program under the oversight of the California Regional Water Quality Control Board, Los Angles Region. One monitoring location is monitored downgradient of Boeing RFI Subarea 5/9 South Unaffiliated Areas: Outfall 002 at the south end of Group 10. This discharge point is the ultimate discharge point for a large portion of the western half of SSFL. Ongoing monitoring and evaluation is being conducted under the NPDES program. NPDES data will be considered during preparation of future Boeing RFI documentation. Ongoing seeps and springs investigation and evaluation is being conducted under the Chatsworth Formation Operable Unit RI program and will be incorporated into groundwater DQO evaluations for the Unaffiliated Areas. Review of analytical data, field notes, and field logs from all prior field investigations were reviewed. Based on a review of field notes and records, no observations have been made during field activities that suggest a chemical release may have occurred other than those documented in the Group 5 RFI Report (CH2M HILL, 2008) and Group 9 RI Report (NASA, 2009). No, currently under review No, currently under review Yes TBD TBD No Notes: a Activities presented in this table are consistent with the activities presented in Figure 2 of the DQO Report ( CH2M HILL, 2013c). b A "Yes" response to this question indicates a release or potential release that has not already been identified, investigated, and documented in the CH2M HILL 2008 Group 5 RFI Report was identified. A release or potential release can result in identification of a new CUA (if constituent concentrations in the screening level sample exceed characterization levels or if there is clear documentation that release of chemicals to the environment has occurred) or can represent a new source and/or new chemical(s) associated with an existing CUA. The status of each activity is designated by a color. The colors represent the following: DQO activity complete, no additional work required, no new CUA or existing CUA relevant new information identified. Additional investigation is required to determine if a new release or potential release is identified. See Table A 2. After evaluation of data collected during the proposed investigation, recommendations of CNFA or a new CUA will be made. Acronyms: CMS = corrective measures study CNFA = conditional no further action CUA = chemical use area DOE = United States Department of Energy DQO = data quality objectives DTSC = California Environmental Protection Agency, Department of Toxic Substances Control GIS = geographic information system NASA = National Aeronautics and Space Administration NPDES = National Pollutant Discharge Elimination System RFA = RCRA facility assessment RFI = RCRA facility investigation RI = remedial investigation SMOU = Surficial Media Operable Unit SOP = standard operating procedure SSFL = Santa Susana Field Laboratory SWMU = Solid Waste Management Units USEPA = United States Environmental Protection Agency Sources: CH2M HILL Group 5 Central Portions of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California. November. CH2M HILL. 2013a. Recommended Approach for Assessing the Vapor Intrusion Pathway, Boeing RCRA Facility Investigation Project, Santa Susana Field Laboratory. March. CH2M HILL. 2013b. Recommended Approach for Air Dispersion Modeling, Boeing RCRA Facility Investigation Project, Santa Susana Field Laboratory. (Appendix B to the DQO Report). March. CH2M HILL. 2013c. Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California. March. CH2M HILL and MWH Standard Operating Procedure, Onsite Debris Survey and Sampling Methodology, Santa Susana Field Laboratory, Ventura County, California. Prepared for The Boeing Company, United States Department of Energy, National Aeronautics and Space Administration. November. Montgomery Watson Harza (MWH). 2012a. Natural Gas Pipeline GIS Feature Class Technical Memorandum. Montgomery Watson Harza (MWH). 2012b. Recommended Approach for Evaluating Vadose Zone Mass Flux of Contaminants to Groundwater. National Aeronautics and Space Administration (NASA) Draft Group 9 Remedial Investigation Report. November. ES BAO PAGE 3 OF 3

25 TABLE A 2 Potential CUA Investigation and Supplemental Conditional NFA Area Weight of Evidence Documentation for the SMOU, Boeing RFI Subarea 5/9 South Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California Activities to Support CNFA Area Recommendations for the SMOU a Aerial Photograph Review Description of the newly identified suspect feature or area of interest associated with the release or potential release Two vegetation clearance areas were identified near in the southwestern portion of Boeing RFI Subarea 5/9 South during the 2010/2011 review of aerial photographs (see Figure A 1). CNFA Weight of Evidence Documentation, Question 2: Is the feature or area of interest located within a CUA that has previously been identified? CNFA Weight of Evidence Documentation, Question 3: Was a release of any chemical previously used, stored, handled, or disposed documented at the feature or area of interest? CUA Reference ID or, if not located within previously identified CUA and does not meet criteria for new CUA, identify new potential CUA ID Data Gap Screening Samples to be collected in accordance with DQO Report Table 2 (Field Sampling Methodologies for CUA or CNFA Determination for the SMOU)? b No No A Yes. Samples will be collected and analyzed consistent with DQO Report Table 2. See Table C 1 in Appendix C for details on the proposed samples. CNFA Weight of Evidence Documentation, Question 4: Were chemicals detected at concentrations that exceed characterization levels in screening level samples? To be determined after the Boeing RFI Subarea 5/9 South Unaffiliated Areas data gap work plan is implemented. Notes: a All tasks and activities in Figure 2 of the DQO Report (CH2M HILL, 2013) have been reviewed and all available and relevant information was confirmed to either be presented in the 2008 Group 5 RFI Report (CH2M HILL, 2008), presented in the 2009 Group 9 RI Report (NASA, 2009), or is included in the table above. Refer to Figure A 1 for the locations of features identified in this table. b Analytical methods and sample depths for proposed data gap samples are presented in Tables C 1 and C 2 in Appendix C. Color designation represents: Additional investigation is required to determine if a new release or potential release is identified. After evaluation of data collected during the proposed investigation, recommendations of CNFA or a new CUA will be made. Acronyms: CNFA = conditional no further action COPC = chemical of potential concern CUA = chemical use area DQO = data quality objective RFI = RCRA facility investigation SMOU = Surficial Media Operable Unit Sources: CH2M HILL Group 5 Central Portions of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California. November. CH2M HILL Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California. March. National Aeronautics and Space Administration (NASA) Draft Group 9 Remedial Investigation Report. March. ES BAO PAGE 1 OF 1

26 VICINITY MAP UNDEVELOPED LAND NASA UNDEVELOPED LAND AREA III AREA II AREA I AREA IV UNDEVELOPED LAND LEGEND Newly Identified Features (For a complete list of newly identified features, see Tables A-1 and A-2)! Proposed Soil Vapor Sample Location # Proposed Soil Sample Location BASEMAP LEGEND Boeing RFI Site Dirt Road RFI Group Boundary Paved Road Administrative Boundary Rock Outcrop Chemical Use Area (CUA) Pond 1 CUA Reference Number Transformer Pad!!!!!!!!!! CUA Cluster (CC) Structure!!!!! Boeing RFI Subarea 5/9 South Area being investigated by NASA as part of the Coca RFI site Potential CUA A Potential CUA ID Soil CMS Area Soil Vapor CMS Area Features ' Debris Point! Transformer Pole Pipeline Leach Field Line Debris Line Drainage Channel Operational Channel Aboveground Storage Tank Underground Storage Tank Not Yet Determined Storage Yard Debris Area Disturbed Soil Vegetation Clearing Excavation Area U U U U U U U U Undefined Feature U U U U Spray Field Leach Field Area Septic Tank Sump # # #!( *! ( * * A!(!( ## **!! (( $ Feet in = 600 ft FIGURE A-1 Newly Identified Features and Potential CUAs, Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California SCO K:\BOEING\362070\MAPFILES\2013\DQO\SUBAREA5_9_SOUTH\REPORTFIGURES\SUB59S_FIGUREA-1_NEWFEATURES.MXD RANHORN 5/17/2013 9:47:31 AM

27 VICINITY MAP UNDEVELOPED LAND NASA UNDEVELOPED LAND AREA III AREA II AREA I AREA IV UNDEVELOPED LAND A ## ** # * Notes: 1) For the purpose of this figure, Soil Characterization Levels are the lowest of applicable Suburban Residential RBSLs and Ecological RBSLs, or are the background level if the background level is greater than one or more RBSLs 2) All chemicals for which a screening level exists are presented on this figure. LEGEND Soil Detect, <= Soil Characterization Levels Detect, > Soil Characterization Levels but <= 2x Soil Characterization Levels Detect, > 2x Soil Characterization Levels but <= 10x Soil Characterization Levels Detect, > 10x Soil Characterization Levels but <= 100x Soil Characterization Levels Detect, > 100x Soil Characterization Levels Non-detect # Proposed Soil Sample Location BASEMAP LEGEND Boeing RFI Site Dirt Road RFI Group Boundary Paved Road Administrative Boundary Rock Outcrop Chemical Use Area (CUA) Pond 1 CUA Reference Number Transformer Pad!!!!!!!! CUA Cluster (CC) Structure Boeing RFI Subarea 5/9 South Area being investigated by NASA as part of the Coca RFI site Potential CUA A Potential CUA ID Soil CMS Area Soil Vapor CMS Area Features ' Debris Point! Transformer Pole Pipeline Leach Field Line Debris Line Drainage Channel Operational Channel Aboveground Storage Tank Underground Storage Tank Not Yet Determined Storage Yard Debris Area Disturbed Soil Vegetation Clearing Excavation Area U U U U U U U U U UUndefined Feature U U U U U Spray Field Leach Field Area Septic Tank Sump Feet FIGURE A-2 Comparison of Analytical Results to Characterization Levels for Soil from 0 to 2 Feet Below Ground Surface, Subarea 5/9 South Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California $ 1 in = 600 ft SCO K:\BOEING\362070\MAPFILES\2013\DQO\SUBAREA5_9_SOUTH\REPORTFIGURES\SUB59S_FIGUREA-2_0_2.MXD RANHORN 5/21/ :42:12 AM

28 VICINITY MAP UNDEVELOPED LAND NASA UNDEVELOPED LAND AREA III AREA II AREA I AREA IV UNDEVELOPED LAND A ## ** SCO K:\BOEING\362070\MAPFILES\2013\DQO\SUBAREA5_9_SOUTH\REPORTFIGURES\SUB59S_FIGUREA-3_2_10.MXD RANHORN 5/21/ :48:36 AM Notes: 1) For the purpose of this figure, Soil Characterization Levels are the lowest of applicable Suburban Residential RBSLs and Ecological RBSLs, or are the background level if the background level is greater than one or more RBSLs 2) All chemicals for which a screening level exists are presented on this figure. LEGEND Soil Detect, <= Soil Characterization Levels Detect, > Soil Characterization Levels but <= 2x Soil Characterization Levels Detect, > 2x Soil Characterization Levels but <= 10x Soil Characterization Levels Detect, > 10x Soil Characterization Levels but <= 100x Soil Characterization Levels Detect, > 100x Soil Characterization Levels Non-detect # Proposed Soil Sample Location BASEMAP LEGEND Boeing RFI Site Dirt Road RFI Group Boundary Paved Road Administrative Boundary Rock Outcrop Chemical Use Area (CUA) Pond 1 CUA Reference Number Transformer Pad!!!!!!!! CUA Cluster (CC) Structure Boeing RFI Subarea 5/9 South Area being investigated by NASA as part of the Coca RFI site Potential CUA A Potential CUA ID Soil CMS Area Soil Vapor CMS Area Features ' Debris Point! Transformer Pole Pipeline Leach Field Line Debris Line Drainage Channel Operational Channel Aboveground Storage Tank Underground Storage Tank Not Yet Determined Storage Yard Debris Area Disturbed Soil Vegetation Clearing Excavation Area U U U U U U U U Undefined Feature U U U U Spray Field Leach Field Area Septic Tank Sump Feet in = 600 ft FIGURE A-3 Comparison of Analytical Results to Characterization Levels for Soil from 2 to 10 Feet Below Ground Surface, Subarea 5/9 South Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California $ 1

29 VICINITY MAP UNDEVELOPED LAND NASA UNDEVELOPED LAND AREA III AREA II AREA I AREA IV UNDEVELOPED LAND LEGEND A!(!(!(!(!! (( Notes: 1) For the purpose of this figure, Soil Characterization Levels are the lowest of applicable Suburban Residential RBSLs and Ecological RBSLs; Soil Vapor Characterization Levels are the lowest of applicable Vapor Intrusion Characterization Levels and Ecological Low Toxicity Reference Values. 2) All chemicals for which a screening level exists are presented on this figure. ") Detect, <= Soil or Soil Vapor Characterization Levels Detect, > Soil or Soil Vapor Characterization Levels ") but <= 2x Soil or Soil Vapor Characterization Levels Detect, > 2x Soil or Soil Vapor Characterization Levels but <= 10x Soil or Soil Vapor Characterization Levels Detect, > 10x Soil or Soil Vapor Characterization Levels but <= 100x Soil or Soil Vapor Characterization Levels ") ") ") Detect, > 100x Soil or Soil Vapor Characterization Levels ") Non-detect * Soil ( Soil Vapor! Proposed Soil Vapor Sample Location # Proposed Soil Sample Location BASEMAP LEGEND Boeing RFI Site Dirt Road RFI Group Boundary Paved Road Administrative Boundary Rock Outcrop Chemical Use Area (CUA) Pond 1 CUA Reference Number Transformer Pad!!!!!!!!!! CUA Cluster (CC) Structure Boeing RFI Subarea 5/9 South Area being investigated by NASA as part of the Coca RFI site Potential CUA A Potential CUA ID Soil CMS Area Soil Vapor CMS Area Features ' Debris Point! Transformer Pole Pipeline Leach Field Line Debris Line Drainage Channel Operational Channel $ 1 Aboveground Storage Tank Underground Storage Tank Not Yet Determined Storage Yard Debris Area Disturbed Soil Vegetation Clearing Excavation Area U U U U U U U U U U Undefined Feature U U U U U Spray Field Septic Tank Leach Field Area Sump Feet in = 600 ft FIGURE A-4 Comparison of Analytical Results to Characterization Levels for VOCs (Soil and Soil Vapor) from 0 to 10 Feet Below Ground Surface, Subarea 5/9 South Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California SCO K:\BOEING\362070\MAPFILES\2013\DQO\SUBAREA5_9_SOUTH\REPORTFIGURES\SUB59S_FIGUREA-4_0_10.MXD RANHORN 5/22/ :43:35 PM

30 Appendix B Responses to DTSC Comments Relevant to the Unaffiliated Areas

31 Appendix B Contents No comments have been received to date that specifically relate to the Boeing RFI Subarea 5/9 South Unaffiliated Areas. SFO\ B-1 ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

32 Appendix C Unaffiliated Areas Data Gap Sampling and Analysis Plan

33 Unaffiliated Areas Data Gap Sampling and Analysis Plan, Santa Susana Field Laboratory, Ventura County, California Prepared for The Boeing Company May 2013 Prepared by COPYRIGHT 2013 BY CH2M HILL, INC.

34 Contents Section Page Acronyms and Abbreviations... v 1.0 Introduction Summary of Proposed Samples for the Unaffiliated Areas Field Sampling Procedures Sampling Guidelines Soil Soil Vapor Analytical Guidelines Criteria for Contingent Analyses Criteria for Contingent Samples Quality Assurance/Quality Control Sampling Requirements Step out and Step down Samples References... 4 Tables C 1 Boeing RFI Subarea 5/9 South Unaffiliated Areas Proposed Data Gap Sampling and Analysis C 2 Unaffiliated Areas Soil and Soil Vapor Analyses Figure C 1 Proposed Sample Locations for the Subarea 5/9 South Unaffiliated Areas SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC. iii

35 Acronyms and Abbreviations bgs DQO DTSC MRL QA/QC QAPP RCRA RFI SAP SOP SSFL Unaffiliated Areas VOC below ground surface data quality objective California Environmental Protection Agency, Department of Toxic Substances Control method reporting limit quality assurance/quality control Quality Assurance Project Plan Resource Conservation and Recovery Act RCRA facility investigation sampling and analysis plan standard operating procedure Santa Susana Field Laboratory Subarea 5/9 South Areas Unaffiliated with RFI Sites volatile organic compound SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC. v

36 Unaffiliated Areas Data Gap Sampling and Analysis Plan, Santa Susana Field Laboratory, Ventura County, California 1.0 Introduction This document presents the data gap sampling and analysis plan (SAP) for the areas not affiliated with Resource Conservation and Recovery Act (RCRA) facility investigation (RFI) sites in Boeing RFI Subarea 5/9 South at the Santa Susana Field Laboratory (SSFL) in Ventura County, California. The purpose of this SAP is to present the plan for addressing data gaps identified within the Boeing RFI Subarea 5/9 South Areas Unaffiliated with RFI Sites (Unaffiliated Areas) through the comprehensive data quality objective (DQO) evaluation. The data gaps identified for the Unaffiliated Areas are presented in the Addendum to Master Resource Conservation and Recovery Act Facility Investigation Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Areas Unaffiliated with RFI Sites, Santa Susana Field Laboratory, Ventura County, California (Master RFI Data Gap Work Plan) (CH2M HILL, 2013a). The SAP presented herein describes how and where data will be collected to address the data gaps identified within the Unaffiliated Areas. 2.0 Summary of Proposed Samples for the Unaffiliated Areas Table C 1 presents the sample media, sample depth, and analytes for each sample proposed for collection within the Unaffiliated Areas. In addition, Table C 1 presents the rationale and the specific DQOs that each proposed sample are intended to satisfy. Table C 2 presents the laboratory analytical methods proposed for the analytes listed in Table C 1. Figure C 1 presents the locations of the proposed samples. The proposed samples presented in Table C 1 and on Figure C 1 were identified based on the characterization sampling and analysis strategy presented in the Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California (DQO Report) (CH2M HILL, 2013b) for surface water bodies, soil and sediment, and the vadose zone. Samples will be collected from the locations presented in Table C 1 and Figure C 1. However, field staff will field check proposed sample locations relative to site drainage patterns, surface slope, and topography and will use professional judgment to modify sample locations accordingly. In addition, field staff will field check proposed sample locations relative to existing structures, rock outcrops, above and belowground utilities, or other obstacles and adjust the sample locations accordingly. The final locations of each sample will be recorded using handheld global positioning system equipment. Soil sample depths may also be adjusted from the depths shown in Table C 1 based on observed staining, discoloration, or elevated volatile organic compound (VOC) levels recorded with a photoionization detector during drilling. Sample location identifications were developed using the two digit code that indicates the RFI site associated with the sample (U5 [for samples within Group 5] and U9 [for samples within Group 9] were used for samples within the Unaffiliated Areas), followed by the two digit code that indicates the sample/matrix type (for example, BS was used for soil boring samples and SV was used for soil vapor samples), followed by four numerical digits (starting with 2000 at each site). For example, a sample numbered U5BS2002 would be a soil boring sample (BS) and is the third consecutively numbered sample (2002) collected at within Group 5 in the Unaffiliated Areas. 3.0 Field Sampling Procedures Samples will be collected in accordance with the SSFL standard operating procedures (SOPs) (Boeing, 2013), which were submitted to and approved by DTSC in March Prior to sample collection, sample locations will be cleared of vegetation, SSFL utility diagrams will be reviewed, sample locations will be staked, third party utility surveys will be performed, and DigAlert will be contacted. The sample locations may be adjusted based on SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

37 UNAFFILIATED AREAS DATA GAP SAMPLING AND ANALYSIS PLAN, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA information regarding subsurface utilities or other subsurface structures provided by the third party utility survey company and DigAlert. The final locations of each sample will be recorded using handheld global positioning system equipment. 3.1 Sampling Guidelines Samples will be collected in accordance with the DQO Report and field SOPs. However, additional guidelines for soil and soil vapor sample collection are outlined in Sections and Soil In cases where all the planned soil samples at a specific location cannot be collected due to the presence of bedrock, a soil sample will be collected just above the depth where the rig encountered refusal. However, the soil sample will not be collected from the refusal depth if the following two criteria are satisfied: A more shallow sample(s) was collected at the same location and The bottom depth of the shallower sample(s) would be less than 2 feet above the top of the refusal depth sample. In accordance with DQO Report Table 6, step out samples are typically collected at the same depth as the original sample with concentrations that exceed characterization levels. However, VOC step out soil samples will not be collected from a more shallow depth than 1.5 feet (bottom sample depth). For example, if the original sample that contained VOCs at concentrations that exceed the corresponding characterization levels was collected from 0.5 feet below ground surface (bgs), the step out sample for that location would be collected from 1.5 feet bgs Soil Vapor Soil vapor samples will be collected from a minimum depth of 5 feet bgs. In cases where a soil vapor sample cannot be collected from at least 5 feet bgs due to refusal on bedrock or inadequate air flow, a soil sample will be collected in lieu of the soil vapor sample and analyzed for VOCs. This soil sample will be collected to support an evaluation of the vapor intrusion pathway. The soil sample will be collected from the maximum depth possible at that location, but no shallower than 3 feet bgs. The soil sample will not be collected if refusal on bedrock is encountered shallower than 3 feet bgs. In addition, the soil sample will not be collected if previous soil samples collected from greater than 3 feet bgs at that location were analyzed for VOCs. At locations where a soil vapor sample may be collected from a minimum depth of 5 feet bgs but deeper samples cannot be collected from the proposed sample depths due to the presence of bedrock, a soil vapor sample will be collected just above the depth where the rig encountered refusal. However, the soil vapor sample will not be collected from the refusal depth if the bottom depth of the shallower soil vapor sample(s) would be less than three feet above the top of the refusal depth soil vapor sample. 4.0 Analytical Guidelines Table C 1 presents the chemicals that are proposed for analysis in each sample. Table C 2 presents the analytical methods that are proposed for use during implementation of this SAP. The Surficial Media Operable Unit Quality Assurance Project Plan (QAPP) (MECx, 2012] presents the specific chemicals that will be analyzed and reported under each method. Soil samples will be homogenized by the analytical laboratories in accordance with Boeing SSFL SOP 21, Soil Sampling. Analytical guidelines that were followed during preparation of this SAP include: For features where the historical uses are not known (and therefore, the chemical uses are also unknown), a screening for total petroleum hydrocarbons, VOCs, semivolatile organic compounds, and metals will be performed. Soil at these features also might be analyzed for other chemical groups based on the chemical uses of adjacent features/rfi sites. 2 SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

38 4.1 Criteria for Contingent Analyses UNAFFILIATED AREAS DATA GAP SAMPLING AND ANALYSIS PLAN, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA In some cases, the need for performing select analytical methods is contingent on the results of performing other analytical methods on a particular sample. In these cases, the laboratory will be notified to hold the sample for analysis of select constituents until CH2M HILL has the opportunity to review the results of other analyses performed on the sample. CH2M HILL will notify the laboratory if analysis for the held constituents is necessary based on these results (based on a comparison of the analytical results to characterization levels). Table C 1 identifies the constituents that will be held for analysis by the laboratory pending the results of other analytical methods. Examples of contingent analyses include: In accordance with DQO Report Table 2, for newly identified features for which VOCs are listed for analysis in soil and soil vapor, the VOCs in soil samples will only be collected if the VOCs in soil vapor sample cannot be collected (either due to refusal on bedrock at a depth more shallow than 5 feet bgs or due to poor air flow in the soil vapor probe). 4.2 Criteria for Contingent Samples In some cases, the need for collecting a sample is contingent on the analytical results of other samples. Table C 1 identifies the samples that will be held for collection or analysis pending the analytical results of other samples. Examples of contingent samples include: In cases where the 10 foot bgs sample is collected in the field, lab analysis of that sample will sometimes be held by the lab until CH2M HILL provides direction to analyze the sample. CH2M HILL will evaluate the need for lab analysis based on the results of samples above the proposed sample (generally based on analytical data for the 6 foot bgs sample). The 10 foot bgs sample will generally be analyzed by the lab (following direction from CH2M HILL) if constituents are detected above characterization levels in the 6 foot bgs sample. The need to analyze the 10 foot bgs sample is also dependent on the site conceptual model. In some cases, samples will be recollected to address previous method reporting limits (MRLs) that exceed characterization levels. One instance in which samples may be recollected to address elevated MRLs is for analytes with previous elevated MRLs that have never been detected in the reporting area. If an analyte was never detected in the reporting area, data for that analyte would generally not be included in the risk assessment for that reporting area. Therefore, greater assurance that the analyte is not present above characterization levels is desired. Soil and soil vapor samples are proposed for collection in Table C 1 to address this uncertainty. However, if the specific analytes that have not been detected previously are detected in one or more of the other samples planned for collection, the samples proposed to address this issue will not be collected. 5.0 Quality Assurance/Quality Control Sampling Requirements Laboratory analysis will be performed in accordance with the QAPP (MECx, 2012). The QAPP describes the quality assurance/quality control (QA/QC) requirements for SSFL and identifies the analytical methods, method detection limits, and analyte lists for the constituents used at SSFL. In accordance with the QAPP, QA/QC samples will be collected and analyzed at the following frequency: Field Duplicate: Collected on a 5 percent frequency for each matrix and for each type of analysis. Laboratory Split: Collected on a 5 percent frequency for each matrix for each type of analysis. Split samples are analyzed by a laboratory other than the primary laboratory. Matrix Spike/Matrix Spike Duplicate: Collected on a 5 percent frequency for each matrix and for each type of analysis. Equipment Blanks: One sample collected per day for each equipment type that is decontaminated. Trip Blank: One sample per cooler containing samples for analysis of VOCs. SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

39 UNAFFILIATED AREAS DATA GAP SAMPLING AND ANALYSIS PLAN, SANTA SUSANA FIELD LABORATORY, VENTURA COUNTY, CALIFORNIA 6.0 Step-out and Step-down Samples Following the collection of the proposed samples identified herein, the need to collect step out (to define lateral extent to required characterization levels) and step down (to define vertical extent to required characterization levels) samples will be assessed. If the samples proposed herein are found to contain constituents at concentrations that exceed the required characterization levels and the extents of the elevated concentrations are not defined by concentrations in existing samples, step out and step down samples will be collected using the characterization sampling and analysis strategy presented in the DQO Report (CH2M HILL, 2013b). For soil and sediment, step down samples will be collected to the maximum depth possible using a hand auger or direct push rig. Step down samples will not be re attempted at locations that have previously been drilled to (and characterized at) the maximum depth that may be accessed with a hand auger or direct push rig. The vadose zone is addressed by DQO Report Table 8. The results of all data gap sampling within the Unaffiliated Areas will be presented in a future data summary and findings report for Boeing RFI Subarea 5/9 South. 7.0 References The Boeing Company (Boeing) Standard Operating Procedures for Areas I and III of the Santa Susana Field Laboratory, Ventura County, California. March. CH2M HILL Group 5 Central Portions of Areas III and IV RCRA Facility Investigation Report, Santa Susana Field Laboratory, Ventura County, California. November. CH2M HILL. 2013a. Addendum to Master RCRA Facility Investigation Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California. March. CH2M HILL. 2013b. Comprehensive Data Quality Objectives, RCRA Facility Investigation, Santa Susana Field Laboratory, Ventura County, California. March. MECx Quality Assurance Project Plan, Santa Susana Field Laboratory (SSFL) RCRA Field Investigation, Surficial Media Operable Unit, Revision 5. November. 4 SFO\ ES BAO COPYRIGHT 2013 BY CH2M HILL, INC.

40 Tables

41 TABLE C 1 Boeing RFI Subarea 5/9 South Unaffiliated Areas Proposed Data Gap Sampling and Analysis Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California Analytical Suite Chemical Use Area No. Location ID Location Matrix Within Vegetation Clearance Area Sample Depth (feet bgs) A U9BS2000 Soil 0.5 X X TPH (ext.) VOCs (Full) VOCs (Soil Vapor) SVOCs Metals ph PCBs Energetics DQO Cross Reference Figure 2 and Table 2 DTSC Comment No. Cross Reference A U9BS2000 Soil 1.5 X X A U9BS2000 Soil 6 b X VH X X A U9BS2000 Soil 10 H H H A U9SV2000 Soil Vapor 5.5 X A U9SV2000 Soil Vapor 10.5 c H A U9BS2001 Within Vegetation Clearance Area Soil 0.5 X X Figure 2 and Table 2 N/A A U9BS2001 Soil 1.5 X X A U9BS2001 Soil 6 b X VH X X A U9BS2001 Soil 10 H H H A U9SV2001 Soil Vapor 5.5 X A U9SV2001 Soil Vapor 10.5 c H A U9BS2002 Within Vegetation Clearance Area Soil 0.5 X X Figure 2 and Table 2 N/A A U9BS2002 Soil 1.5 X X A U9BS2002 Soil 6 b X VH X X A U9BS2002 Soil 10 H H H A U9SV2002 Soil Vapor 5.5 X A U9SV2002 Soil Vapor 10.5 c H A U9BS2003 Downstream from Vegetation Soil 0.5 X X Figure 2 and Table 2 N/A A U9BS2003 Clearance Area Soil 1.5 X X X A U9BS2003 Soil Base of Alluvium a X X X X A U9BS2004 Downstream from Vegetation Soil 0.5 X X Figure 2 and Table 2 N/A A U9BS2004 Clearance Area Soil 1.5 X X X A U9BS2004 Soil Base of Alluvium a X X X X A U9BS2005 Within Vegetation Clearance Area Soil 0.5 X X Figure 2 and Table 2 N/A A U9BS2005 Soil 1.5 X X A U9BS2005 Soil 6 b X VH X X A U9BS2005 Soil 10 H H H A U9SV2005 Soil Vapor 5.5 X A U9SV2005 Soil Vapor 10.5 c H A U9BS2006 Within Vegetation Clearance Area Soil 0.5 X X Figure 2 and Table 2 N/A A U9BS2006 Soil 1.5 X X A U9BS2006 Soil 6 b X VH X X A U9BS2006 Soil 10 H H H A U9SV2006 Soil Vapor 5.5 X A U9SV2006 Soil Vapor 10.5 c H A U9BS2007 Within Vegetation Clearance Area Soil 0.5 X X Figure 2 and Table 2 N/A A U9BS2007 Soil 1.5 X X A U9BS2007 Soil 6 b X VH X X A U9BS2007 Soil 10 H H H A U9SV2007 Soil Vapor 5.5 X A U9SV2007 Soil Vapor 10.5 c H N/A Rationale/Objectives Newly identified vegetation clearance area observed during the 2010/11 aerial photograph review. Newly identified vegetation clearance area observed during the 2010/11 aerial photograph review. Newly identified vegetation clearance area observed during the 2010/11 aerial photograph review. First surface migertation sample downstream from vegetation clearance area. Second surface migertation sample downstream from vegetation clearance area. Newly identified vegetation clearance area observed during the 2010/11 aerial photograph review. Newly identified vegetation clearance area observed during the 2010/11 aerial photograph review. Newly identified vegetation clearance area observed during the 2010/11 aerial photograph review. ES BAO PAGE 1 OF 2

42 TABLE C 1 Boeing RFI Subarea 5/9 South Unaffiliated Areas Proposed Data Gap Sampling and Analysis Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California Analytical Suite Chemical Use Area No. Location ID Location Matrix Within Vegetation Clearance Area Sample Depth (feet bgs) A U9BS2008 Soil 0.5 X X A U9BS2008 Soil 1.5 X X A U9BS2008 Soil 6 b X VH X X A U9BS2008 Soil 10 H H H A U9SV2008 Soil Vapor 5.5 X A U9SV2008 Soil Vapor 10.5 c H A U9BS2009 Downstream from Vegetation Soil 0.5 X X A U9BS2009 Clearance Area Soil 1.5 X X X A U9BS2009 Soil Base of Alluvium a X X X X A U9BS2010 Downstream from Vegetation Soil 0.5 X X A U9BS2010 Clearance Area Soil 1.5 X X X A U9BS2010 Soil Base of Alluvium a X X X X U9BS2011 At previous sampling location Soil 0.5 X X X U9BS2011 BCSS10 Soil 1.5 X X TPH (ext.) VOCs (Full) VOCs (Soil Vapor) SVOCs Metals ph PCBs Energetics DQO Cross Reference Figure 2 and Table 2 Figure 2 and Table 2 Figure 2 and Table 2 N/A DTSC Comment No. Cross Reference N/A N/A N/A Review of Draft Rationale/Objectives Newly identified vegetation clearance area observed during the 2010/11 aerial photograph review. First surface migertation sample downstream from vegetation clearance area. Second surface migertation sample downstream from vegetation clearance area. Re sample at BCSS10 because of MRL exceedances. Total Soil Samples for Analysis Total Soil Samples on Hold Total Soil Vapor Samples for Analysis Total Soil Samples to be Collected 42 Total Soil Vapor Samples to be Collected 14 Total Number of Locations Proposed for Sampling 19 For features for which VOCs are listed for analysis in soil and soil vapor, the VOCs in soil samples will only be collected if the VOCs in soil vapor sample cannot be collected (either due to refusal on bedrock at a depth more shallow than 5 feet bgs or due to poor air flow in the soil vapor probe). ES BAO PAGE 2 OF 2

43 TABLE C 2 Unaffiliated Areas Soil and Soil Vapor Analyses Addendum to Master RFI Data Gap Work Plan, Boeing RFI Subarea 5/9 South, Unaffiliated Areas, Santa Susana Field Laboratory, Ventura County, California Analytical Suite Analytical Method Soil Volatile Organics (VOCs) 8260B Semivolatile Organics (SVOCs) (including Polynuclear Aromatic Hydrocarbons and phthalates) 8270C SIM* Dioxin/Furans 1613B Metals 6010B/ 6020 Mercury 7471A Hexavalent Chromium 7196A Formaldehyde 8315A Perchlorate 6850 Pesticides 8081A Polychlorinated Biphenyls (PCBs) 8082 Herbicides 8151A n Nitrosodiphenylamine (NDMA) 8270C SIM* Energetics 8330A Inorganics 9056A ph 9045C Total Petroleum Hydrocarbons (TPH) 8015B Ammonia Total Kjeldahl Nitrogen SM4500 Cyanide 9012B Alcohols 8015B Soil Vapor VOCs a 8260B a Soil vapor samples will be analyzed on site by a mobile laboratory using Method SW8260B. In addition, at least one confirmation sample will be collected each day, or one per every 10 samples collected, and sent to a fixed laboratory to be analyzed by Method TO 15. Note: See Quality Assurance Project Plan for details on analytical suite and methods ES BAO PAGE 1 OF 1

44 Figure

45 VICINITY MAP U9SV2000!( U9BS2000 U9SV2001 U9SV2002!(!( U9BS2001 A U9BS2003 U9BS2002 U9BS2004 U9SV2005!( U9SV2006 U9BS2005 U9BS2006!(!( U9SV2007 U9BS2007 Sample Locations Detail U9SV2008!( U9BS2008 U9BS2009 U9BS Feet UNDEVELOPED LAND AREA IV BASEMAP LEGEND Boeing RFI Site Dirt Road RFI Group Boundary Paved Road Administrative Boundary Rock Outcrop Chemical Use Area (CUA) Pond 1 CUA Reference Number Transformer Pad!!!!!!!! CUA Cluster (CC)!!!! Structure Boeing RFI Subarea 5/9 South Area being investigated by NASA as part of the Coca RFI site Potential CUA A Potential CUA ID Soil CMS Area Soil Vapor CMS Area Features ' Debris Point! Transformer Pole Pipeline Leach Field Line Debris Line AREA III Drainage Channel UNDEVELOPED LAND Operational Channel AREA II NASA UNDEVELOPED LAND AREA I LEGEND! Proposed Soil Vapor Sample Location # Proposed Soil Sample Location Proposed Soil Vapor Sample Location on hold!( until further evaluation of sample results Proposed Soil Sample Location on hold until further evaluation of sample results Aboveground Storage Tank Underground Storage Tank Not Yet Determined Storage Yard Debris Area Disturbed Soil Vegetation Clearing Excavation Area U U U U U U U U Undefined Feature U U U U Spray Field Septic Tank Leach Field Area Sump # # #!( *! ( * * A!(!( ## **!! (( U9BS2011 $ Feet in = 600 ft FIGURE C-1 Proposed Sample Locations for the Subarea 5/9 South Unaffiliated Areas Addendum to Master RFI Data Gap Work Plan Boeing RFI Subarea 5/9 South, Unaffiliated Areas Santa Susana Field Laboratory, Ventura County, California SCO K:\BOEING\362070\MAPFILES\2013\DQO\SUBAREA5_9_SOUTH\REPORTFIGURES\SUB59S_FIGUREC-1_PROPSAMPLES.MXD RANHORN 5/17/2013 9:54:09 AM