1. VI Draft Guidance: Overview of Comments to November, 2002 OSWER VI Guidance Michael Sowinski DPRA, Inc.

2. Presentation Overview  Overview the Major Points By Commenters  Comments Organized By: –Generally Applicable Comments –Tier I Comments –Tier II Comments –Tier III Comments –Appendices  Summarize Primary Issues Raised

3. Overview of Comments Provided  30 Commenters –18 Government (Federal & State) –4 Industry Trade Associations –7 Consultants –1 Public Interest Group  6 EPA Supporting Documents  Widely Ranging Comments  Available on E-Docket

4. Generally Applicable Comments  Many Praises for the Effort  Guidance is Overly Conservative  Guidance is Overly Complex  Guidance is Over/Under Prescriptive  VI Guidance will Cause Cleanup Delays  VI Guidance will Delay EI Attainment

5. Generally Applicable Comments: Risk Assessment/Risk Management Issues  Use of Phrase “Pathway Incomplete” vs. “Complete w/Acceptable Risk” is Confusing  Use of OSHA PELs for Occupational Setting!  Appropriateness of the MCL Floor  Incremental vs. Cumulative Risk  Hazard Quotient of 0.2 vs. 1.0.

6. Generally Applicable Comments: Risk Assessment/Risk Management Issues (cont.)  Indoor Sources & Background Contamination! –Procedures to Discriminate Needed –Generic AFs Do Not Account for Background –Guidance Should Provide Citations for Available Background Data (Background Floor)  Tables 2 and 3 –Acceptable Risk? (10-4 – 10-6) –Ever-Changing Toxicology Demands Living Tables. –Extrapolated vs. Non-Extrapolated Values  Short Term vs. Long Term Exposure  Detection Levels vs. Risk Targets for Air and Groundwater

7. Generally Applicable Comments: Scope of Guidance  Applicability to Petroleum Hydrocarbons –Citing Biodegradation, Deal with Petroleum Hydrocarbons Separately –UST Sites vs. Petroleum Hydrocarbon Sites –Do Not Endorse RBCA Guidance  Table 1 COC List –Inclusion of Additional COCs –COC List vs. CAA Hazardous Air Pollutants –COC List vs J & E Spreadsheets  Retroactive Application at CERCLA/VCP Sites  Relation to CERCLA Risk Assessment

8. Generally Applicable Comments: Purpose of Guidance  Need for Guidance on Additional Items –More Advice on Air Sampling –Prepare a Background Source Study –Advice on Delineating Risk, Cumulative Risk, and Triggers for Cleanup Actions –How to Measure for Model Inputs  Guidance Should be Less Prescriptive  Risk Management vs. Risk Assessment

9. Tier 1 Comments  Precluding Factors –Ask Once –More Justification Needed/Suggestions Provided  CSM Should Include Breakdown Products  Should Consider Presence of Vapor Barriers During Tier 1  The Use of Existing vs. New Data – Need Clarity –What Qualifies as Reasonable Estimate of GW

10. Tier 1 Comments  100 Foot Lateral and Vertical Limits  Future Development Issues –Design and Enforcement of Institutional Controls –Guidance Lacks Direction on This  Immediate Action –Focus on Background Contamination –Use of Engineering Controls – Needs Clarity

11. Tier 2 Comments: General  Use of Bulk Soil Samples  Joint Use of Soil Gas & Groundwater Samples – Need Clarity.  Generic vs. Chemical Specific AFs

12. Tier 2 Comments: Empirical AFs  Generic AFs are Over Conservative –Utilize Max. vs. Mean IA Data –Site Selection Bias Exists –Does Not Adequately Account for Background –Henry’s Law Based Equilibrium Assumption  Suggestions Provided for Alternative AFs  More Field Data Required (Data Quality Guidelines Should Be Imposed On Submitting Agency)  Same Database to Create & Validate Data

13. Tier 2 Comments: JEM Inputs for Figure 3  More Details Needed to Support Figure 3 Development  Figure 3 Should Assume 10C not 25C  Figure 3’s 5L/min Assumption Conflicts w/Diffusive Transport Assumption  Figure 3 Should Consider More Soil Types  Construction Characteristics Not Properly Accounted For – Commercial Building AFs Vary Greatly from Residential AFs

14. Tier 3 Comments JEM Model  Requires Sophisticated Expertise  Need Better Rationale for Input Parameters –Critical Parameters for JEM  JEM Use Considerations –Effects of Soil Sorption –Transport Across Capillary Fringe –Aqueous Phase Diffusion –Presence of NAPL

15. Appendix A: Data Quality Assurance Considerations  Appropriateness of the Use of the Visual Sampling Plan  Practical Experience Shows That PDLs are Higher Than Appendix A Lists  Explain That Entire Analyte List for Listed Methods Need Not Be Tested  For TO-15, List Costs for SCAN and SIM Mode.

16. Appendix B: Development of A CSM  Provide Hypothetical Site to Illustrate CSM Development  Need Clarity on How To Identify and Deal With Sensitive Populations

17. Appendix D: Development of Tables 1, 2, and 3.  Calculations for Acceptable Indoor Air Levels Do Not Match With Those Used by Region III and Region VI.  Table D-1 Should List Solubility, Henry’s Law, and Maximum Calculated Vapor Concentration  Table D-1 Should Exclude Contaminants That Do Not Meet the Two-Pronged Toxicity and Volatility Test  Table 2 Should Include Screening Values for Non- Residential Scenarios

18. Appendix E: Relevant Methods and Techniques  Appropriateness of Sub-Slab Sampling  Sampling Recommendations Are Not Technically Defensible (indoor air!, soil gas, gw, sub-slab, soil)  Include “Post Sampling” Survey Form

19. Appendix G: Relevant Methods and Techniques (cont.)  More Advice Needed on Sampling for Model Inputs (i.e., soil moisture, bldng. characteristics)  Need More Careful Accounting of Background Contamination  Water Table vs. Water Column Sampling

20. Summary of Comments Steps to Success