Department of Toxic Substances Control Deborah O. Raphael, Director 8800 Cal Center Drive Sacramento, California 95826-3200 Matthew Rodriquez Secretary for Environmental Protection Edmund G. Brown Jr. Governor November 2, 2012 Mr. Peter Zorba National Aeronautics and Space Administration Santa Susana Field Laboratory 5800 Woolsey Canyon Road Canoga Park, California 91304 CLOSURE CERTIFICATION ACKNOWLEDGMENT FOR THE AREA II GROUNDWATER TREATMENT UNITS, SANTA SUSANA FIELD LABORATORY, CANOGA PARK, VENTURA COUNTY, CALIFORNIA, EPA ID NUMBER CA1800090010 Dear Mr. Zorba: On July 14, 2011, the Department of Toxic Substances Control (DTSC) approved a revised Closure Plan (CP) for the following three (3) Hazardous Waste Management Units (HWMUs): the Bravo Groundwater Treatment Unit (GWTU), the Delta GWTU, and the RD-09 GWTU, including the associated pipelines between the groundwater extraction wells and the GWTUs. DTSC received the Groundwater Treatment Units Closure Report for Bravo, Delta, and RD-09, Santa Susana Field Laboratory, Ventura County, California, (Closure Report) dated June 2012. The GWTUs are described in Section 3 and their locations shown on Figure 7 of the CP and Figures 3-1 to 3-6 in the Closure Report. On July 2, 2012, DTSC received a closure certification, dated June 28, 2012, and signed by both the owner and an independent professional engineer registered in California certifying that the HWMUs were closed in accordance with the approved CP. This letter is to inform you that DTSC now considers these three HWMUs and the associated pipelines at your facility closed and acknowledges the Closure Certification submitted on June 29, 2012. Any contamination above background levels are in areas soon to be investigated under the Remedial Investigation Work Plan submitted by the National Aeronautics and Space Administration in compliance with the Administrative Order on Consent. On the basis of the investigation results, these areas might develop into a preliminary remediation area and may require removal of the soils. This acknowledgment is based on the representation that the information submitted, as well as any other information provided to DTSC to use as basis for this decision, is true and Mr. Peter Zorba November 2, 2012 Page 2 accurate. Any inaccuracies found in such information may be grounds for subsequent nullification of the Closure Certification and potential enforcement action. The owner and/or operator must inform DTSC of any deviations from, or changes in, the information provided, which would affect the Closure Certification for these units. Please be advised that this acknowledgment of the above-referenced HWMU closures is not a certification that your facility does not pose any environmental or public health threat. This letter does not remove any liabilities associated with past hazardous waste management practices which occurred at the facility. This Closure Certification does not limit or preclude any future investigations of any other on-site operation by any agency, nor any resulting corrective action, deemed necessary for closure and remediation of any solid waste management units at the facility. This Closure Certification does not constitute termination of a permit or interim status nor is it a determination that corrective action has been terminated. If you have any questions regarding this letter, please contact Paul Ruffin at (916) 255-6677 or via email at Paul.Ruffin@dtsc.ca.gov. Sincerely, Edward Nieto, P.E. Supervising Hazardous Substances Engineer Office of Permitting cc: (via email) Allen Elliott NASA Allen.elliott@nasa.gov Arthur Lenox The Boeing Company Arthur.j.lenox@boeing.com Mohinder S. Sandhu Department of Toxic Substances Control Mohinder.sandhu@dtsc.ca.gov Mr. Peter Zorba November 2, 2012 Page 3 cc: (cnt'd) Mark Malinowski Department of Toxic Substances Control Mark.malinowski@dtsc.ca.gov Roger Paulson Department of Toxic Substances Control Roger.paulson@dtsc.ca.gov Thomas Seckington Department of Toxic Substances Control Tom.seckington@dtsc.ca.gov Paul Ruffin Department of Toxic Substances Control Paul.ruffin@dtsc.ca.gov