1. Vapor Intrusion Guidance Comments & Database USEPA’s (OSWER) 11/03 Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils Presentations of Comments by: Henry Schuver, US EPA Michael Sowinski, DPRA Robert Truesdale, RTI For: 2003 RCRA National Meeting, Wash.DC - Aug. 12, 2003

2. Background on Henry Schuver MS Geology, ASU 17 yrs. Experience: State of NJ, Consultant, EPA Region 2, EPA-HQ OSW since 1997 EI Guidance (2/99) Human & Groundwater Vapor Summit (1/00), Issue kick-off mtg. EIForum2000 Mtg (8/00) w/ 2-days of Vapor experts RCRA EI Vapor Intrusion Guidance (10/01) EIVapor2002 Mtg (1/02) w/ 3-days of Vapor experts Participant OSWER Vapor Intrusion Guidance(11/02) Identified as lead to OSWER Response to Comments Epidemiology- DrPH candidate

3. This presentation is about the Comments Received It is NOT presenting Responses to Comments Quick Review of VI Guidance, H. Schuver, 10 min Overview of Comments, Michael Sowinski, 20 min Comments on Comments, Henry Schuver 20 min Vapor Intrusion Database, Robert Truesdale, 20 min Panel for Q&A and Comments, 20 min

4. Status of OSWER’s draft-Subsurface Vapor Intrusion Guidance Signed Nov. 22, 2002 (for use) By OSWER Assist. Admin. (AA) Marianne Horinko Published in Federal Register Nov. 29, 2002 90-day Comment Period (Nov. 29 - Feb. 27) Guidance, Comments, & Training available at: http://www.epa.gov/correctiveaction/eis/vapor.htm http://www.epa.gov/edocket RCRA-2002-033 http://www.epa.gov/edocket http://www.clu-in.org/conf/tio/vapor_021203/ www.iavi.rti.org (should have these slides + audio) www.iavi.rti.org Response to Comments on-going (latest is here)

5. VI Guidance Workgroup [& contributors] OSWER ’s draft-Vapor Intrusion Guidance Paul Johnson, ASU Todd McAlary, GeoSyn Ian Hers, UBC/Golder Andrew Fan, R3David Bennett, OERRDave Mickunas, ERT Debbie Newberry, OSWERDiane Groth, NJDEPDom. Digiulio, ORD Craig Dukes, SCEdgar Ethington, COFrank Kover, ORD Helen Dawson, R8Henry Schuver, CAPBJeff Crum, MI John Boyer, NJDEPJim Weaver, ATHMatt Hale, OSW Matt Straus, OSWER Paul Locke, MADEPRay Cody, R1 Richard Mattick, OUST Ronald Mosley, RTPSheila Gaston, CO Stiven Foster, ORDTom Aalto, R8 Robbie Ettinger, ShellLeslie Hay-Wilson, SageRDavid Folkes, Env-Grp Blayne Hartman, HP LabsMarcia Bailey, R10Pat Vanleeuwen, R5 A. Guiseppi-Elie, DupontElsie Patton, CTDEPVic Kremsec, BP Tom McHugh, APIBill Wertz, NYDECCraig Mann, EQM

6. Intent? OSWER ’s draft-Subsurface Vapor Intrusion Guidance Tool For assessing if pathway is “complete”: Subsurface contributions only Single pathway (single chemical) – not cumulative at all For screening in (or out) For further consideration (or not) (I.e., potential) Whole facilities/sites (Not for delineating extent) Use changes = reevaluation Not regulation Only guidance – based on current understanding Not requirements or obligations

7. Tier 1- Primary Screening OSWER ’s draft-Subsurface Vapor Intrusion Guidance “quickly identify … any potential exists” Q1 Volatiles? Q2 Buildings? Q3 Immediate concerns? If … not … “incomplete” … proceed to Secondary Screening

8. Tier 2- Secondary Screening OSWER ’s draft-Subsurface Vapor Intrusion Guidance Compare concentrations to numerical criteria Measured or “reasonably estimated” conc. (GW, SG, IAQ) Three risks levels 10-4, 10-5, 10-6 cancer (all HI = 1) Q4 - Generic criteria Based on empirical observations to date (0.1, 0.01, 0.001) ‘Dawson’ VI database, media conc. as shown in Table 2 Q5 – Semi-site-specific criteria Canned J & E model (w/ EPA inputs & site Depth & Soil type Read predicted attenuation off graph & shown Table 3 If … not … incomplete … proceed to Site-Specific

9. Secondary Screening (Q4 & Q5) OSWER Vapor Intrusion Guidance Not applicable if ‘Precluding Factors’ : - Shallow sources (< 5ft below bldg foundation) - Crawlspace homes (w/o liners*) - Very permeable geology - Significant preferential pathways - Sources in unsaturated zone (above the water table fringe?) - Mobile gas plumes (Landfill gas, ‘vapor clouds’) - Very low air exchange rates or v. high (neg.) pressure differentials If there: Proceed to Tier 3 (Q6 Site-Specific Pathway)

10. Calculation of Soil Gas and Groundwater Target Screening Levels Select indoor air target screening level. AF = 0.1 AF = 0.001 AF = 0.01 Shallow soil gas screening level (SGSL shallow ) is 10 times indoor air target screening level. SVSL shallow = IASL * 10 Deep soil gas screening level (SGSL deep ) is 100 times indoor air target level. SVSL deep = IASL * 100 Groundwater screening level (GWSL) is the aqueous concentration corresponding to a soil gas concentration 1000 times greater than the indoor air target level. GWSL = IASL * 1000/Hc Slide by Dr. H. Dawson

11. Conceptual Site Model for Vapor Intrusion Draft-RCRA VI Guidance, 2001 1/10 1/1 1/10 1/100 1/1,000 ‘deep’ groundwater (>5’ bf) 1-/1 (-) Ques. 4 VI Guidance Attenuation Factors

12. Q4 Generic Screen

13. Secondary Screening (Q5) OSWER Vapor Intrusion Guidance Q5: Do media concentrations exceed semi-site specific criteria? (Table 3 (a, b,c)) ‘canned’ J&E model-based conservative model input parameters (all, but) Soil type: sand – loam Depth to contamination: 1 – 30 meters Attenuation factor: (SG & GW specific)

14. Tier 3 – Site-Specific Assess. OSWER ’s draft-Subsurface Vapor Intrusion Guidance Modeling (site-specific) Only to identify ‘most-likely-to-be-impacted’ buildings Combining complex factors, e.g., soil, depth, & building factors If no problem predicted there – (by approp. site-specific model) Interim (EI) determinations don’t need samples to confirm that Direct measurement (confirmation, even if no problem expected) Building-specific foundation and/or indoor air from Subset of potentially affected buildings Before a final decision for vapor intrusion If using indoor air – need more than one + “background”

15. Appendices OSWER ’s draft-Subsurface Vapor Intrusion Guidance A: Data Quality B: Conceptual Site Model C: Flow Charts D: Tables 1, 2, & 3 E: Methods & Techniques F: Empirical Attenuation Factors G: J&E Model “Considerations” H: Community Involvement I: “Background”

16. Thank You for Comments VanCantfort, PhDWisconsin, DNR New Jersey, DEP C. Public En. OversightRCAPAPI Alabama, DEMMichigan, DEQCalf. DTSC Indiana, DEMSchmidt, PhDMcAlary, GeoSyn USWAGDOEMontana, DEQ Penn., DEPCalf. RWQCBOhio, EPA ACCGeyer, SCSOklahoma, DEQ ASTSWMOAlabama, DOTDOD Maine, DEPKaminsky, EarthtechCasabo, Environ. Op. Sheldon, PhDNavy Dept., DODWashington, D.Ecol. Supporting Documents: US EPA Regions, 10, 3, 8 (all Risk Assessors), 2, 9, & Indoor Environ. Div.

17. Next: Overview of Comments By: Michael Sowinski of DPRA MS-Environ. Eng. (UM), J.D. (Vermont) 12 yrs. Environmental Consulting Manages DPRA San Diego Office For OSW Manager of Comment Review Manager Indoor Air Vapor Intrusion db Moved from MD to San Diego 2 yrs ago