1. Area I Burn Pit Santa Susana Field Laboratory RCRA Facility Investigation Work Plan February 19, 2008 Laura Rainey, P.G. Senior Engineering Geologist California Environmental Protection Agency Department of Toxic Substances Control

2. Today’s Discussion Discuss status and scope of DTSC’s review Review questions previously raised regarding Area I Burn Pit investigation Describe additional work proposed to complete the Burn Pit’s RFI 2

3. RFI objectives Identify sources of chemical contamination, what chemicals are involved, and the extent of their occurrence Evaluate where chemical contaminants are, where they go, and how they get there Gather data needed to make decisions on interim or final cleanup measures Obtain sufficient info to complete a risk assessment 3

4. Scope of Review: RFI Work Plan Site History and Chemical Use Site Conditions Nature and Extent of Chemical Impacts – review data for all media (soil, sediment, soil vapor, surface water, groundwater) Screening for radioactive waste 4

5. Previous Questions What is the Area I Burn Pit? Do we have adequate historical documentation that describes past Burn Pit activities? What was burned or disposed of there? What chemicals are left behind? Was radioactive waste burned or disposed of there? Are we looking at all relevant pathways for potential contaminant migration? 5

6. What was the Area I Burn Pit? Established 1958 through 1971. Discontinued in 1971 due to “air pollution considerations”. Operated intermittently from 1971 through 1990. Used for burning, dilution, destruction of various materials. Six acres, six pits ranging in volume from 200 to 10,000 gallons. Burn Pit also had burial/disturbed areas, drum & equipment storage areas, above ground storage tanks and other structures. 6

7. Site Location Map 7

8. Burn Pits 1961 8

9. Burn Pit Modifications 1963 9

10. Historical Soil Sampling Locations 10

11. Proposed Sampling Locations 11

12. Historical Documentation Boeing was required to provide certified compilation of relevant historical documents. These documents are included in Appendix C of the Work Plan These documents include: Inventory logs, records, and available invoices; Operations files Site/facility investigation files Regulatory compliance correspondence, audits, permits, monitoring reports, sampling reports, etc. Deposition testimonies from former workers 12

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17. What was Burned or Disposed of at the Burn Pit? Wastes included: –450,000 gallons of fuels –6,924 igniters –21,300 gallons of process chemicals –13,810 pounds of reactive metals –31,717 gallons of organic solvents –5,121 pounds of explosives –32,932 cubic feet of toxic gases –191 gallons of heavy metal toxics 17

18. Sources of Waste Materials On-site sources (site-wide, including Area IV) Off-Site sources (i.e., Canoga, Vanowen, Desoto & Science Center) 18

19. What Chemicals Were Left Behind? Chemicals identified during previous investigations: 1981-1982 Geophysical surveying, remedial excavations, soil sampling & analysis 1990 soil sampling and analysis 1993 removal of structures, geophysical surveying, metallic-anomaly excavations, soil sampling & analysis 1994 soil sampling & analysis 2003 soil leachate & suface water sampling & analysis 2005 soil sampling & analysis 2006 soil sampling 19

20. What Chemicals Were Left Behind? Need to consider initial materials that were burned, destroyed, or diluted in order to evaluate potential by- products Example – waste burned will potentially result in residual thermal decomposition (i.e., burned) products Table 2-1 (in QAPP, Appendix A) lists potential analytical parameters & their potential thermal decomposition products and associated analytical methods Table 2-2 lists potential analytical parameters & analytical methods that will be used to determine the presence of original waste materials 20

21. Examples – What Chemicals Were Left Behind? From Table 2-1: For acids, screen for total anions (chloride, fluoride, sulfate, nitrate, nitrite, phosphate), pH using USEPA Method 300.0, EPA Method 150.2 For perchlorate-containing propellants, screen for perchlorate using USEPA Method 314.0 21

22. Was Radioactive Waste Burned or Disposed of at Burn Pit? Based on review to date, no definitive information suggests it has, but questions remain… Examples: cesium from Canoga & Desoto (7 pounds in early 1960’s) Na, K, NaK, and Li from Area IV sites Materials from radiological buildings in Area IV (i.e., 4003, 4009, 4023, 4020) Materials from non-radiological buildings in Area IV (i.e., 4057, 4065) 22

23. Are We Looking At Relevant Pathways for Contaminant Migration? Yes. Work Plan addresses the following potential pathways: Air dispersion migration from past burning activities Groundwater migration Surface water and sediment migration Soil Vapor migration 23

24. How do we deal with the uncertainties? Utilize geophysical surveys Utilize radiological materials screening survey Conduct air dispersion modeling with field validation sampling Conduct additional sampling and analyses 24

25. Proposed Work for Addressing Deficiencies Utilizes relevant historical information to better describe & delineate former chemical use areas Conduct air dispersion modeling w/field validation sampling to evaluate potential pathway of airborne particulates from past burning activities Will conduct additional multi-media sampling to complete characterization and determine site- related chemicals of concern Conduct radiological materials screening survey to address uncertainties 25