1. Former DuPont Barksdale Works Project Update June 07, 2006 Great Lakes Visitors Center DuPont CRG

2. June 7, 2005Former DuPont Barksdale Works2 DuPont Company Representatives n Brad Nave: Project Director – DuPont Corporate Remediation Group n Cary Pooler: Project Manager – URS Corporation

3. June 7, 2005Former DuPont Barksdale Works3 Purpose of Meeting n Barksdale: – Reaffirm site priorities and public commitments. – Provide an update on work completed since the December 2005 public meeting. – Provide an overview for planned work for 2006. n Chequamegon-Nicolet National Forest: – Provide a status update on activities.

4. Barksdale Project Priorities and Commitments Review Brad Nave

5. June 7, 2005Former DuPont Barksdale Works5 Project Priorities Four Project Priorities: 1. Continue to provide drinking water that meets appropriate Wisconsin regulatory standards for all site-related compounds to residents with impacted wells. 2. Develop plan for long-term drinking water supply and implement as appropriate. 3. Evaluate for potential off-site surface water issues and take appropriate action. 4. Identify priority source areas and take appropriate action.

6. June 7, 2005Former DuPont Barksdale Works6 Project Priorities Other Commitments: – Continue to work with WDNR in the investigation/cleanup of site impacts. – Continue to be available and communicate with neighbors. – Fulfill commitments on Home Value Protection Plan.

7. June 7, 2005Former DuPont Barksdale Works7 Home Value Protection Plan Home Value Protection Program has expired. – Last municipal water connection was in June 2005. – Eligibility expired for the final group of residents in 4Q2006. – A single vacant lot is the only residential property currently in the program and sale of the property is pending.

8. June 7, 2005Former DuPont Barksdale Works8 Work Completed in 2006 n Alternative Water Supply – Managing invoices, supply, and maintenance with Washburn. – To date, DuPont has paid $93,620.86 in related water supply costs to Washburn. – Well abandonment documentation sent to homeowners and WDNR.

9. June 7, 2005Former DuPont Barksdale Works9 Work Completed in 2006 n Georgia Tech Bio-Pilot – DNT isomers not currently detected in aqueous phase. – System was operated for 5 months and a 90% reduction was observed. – Soil from system taken back to lab to further determine limits of degradation.

11. June 7, 2005Former DuPont Barksdale Works11 Work Completed in 2006 n Site Investigation Work – 2006 Work plan submitted to WDNR in March. n Preliminary approval has been received from WDNR.

12. Planned 2006 Site Investigation Cary Pooler

13. June 7, 2005Former DuPont Barksdale Works13 2006 Site Investigation n 2006 Site Investigation – Investigation has two geographic focus areas: n Northern Area – Investigation multi-faceted. n Southern Area – Investigation focusing on surface soils. – Investigation to begin this month. – Estimated completion of field work is September 2006. – Reporting by the end of the year.

14. June 7, 2005Former DuPont Barksdale Works14 Northern Area Investigation Planned Work n Determine distribution of site-related constituents. – Trenching. – Grid sampling in select aeas. n TNT recovery and disposal as part investigation efforts. n Debris identification and recovery. n Perchlorate distribution in groundwater.

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23. June 7, 2005Former DuPont Barksdale Works23 n Insert maps/pictures of issues/findings.

24. June 7, 2005Former DuPont Barksdale Works24 n Insert maps/pictures of issues/findings.

25. June 7, 2005Former DuPont Barksdale Works25 Southern Area Investigation Grid Sizes

26. June 7, 2005Former DuPont Barksdale Works26 Southern Area Investigation Preliminary Findings n With the exception of one occurrence of benzo(a)pyrene at the residential screening level, arsenic and lead are the only constituents that exceed residential or recreational screening levels. n The extent of contamination is generally limited to soils along historic roadways in the central portion of the parcel. (The one exception being at select samples in the northeastern corner of the parcel.)

27. June 7, 2005Former DuPont Barksdale Works27 n The levels of lead and arsenic observed do not represent an acute health risk, and as such, use of this area for an additional season of occasional recreational activities would not be expected to result in unacceptable exposures. n A waste disposal area (1970s berm) was identified. Waste materials primarily consist of building rubble. Southern Area Investigation Preliminary Findings

28. June 7, 2005Former DuPont Barksdale Works28 n Insert maps/pictures of issues/findings.

29. June 7, 2005Former DuPont Barksdale Works29 Southern Area Investigation Planned Work n Conduct additional sampling for the purposes of delineating specific areas along historic roadways and railways.

30. Chequamegon-Nicolet National Forest Update Brad Nave

31. June 7, 2005Former DuPont Barksdale Works31 Chequamegon National Forest n National Forest Service contacted DuPont in April 2006. – Requested DuPont work with Forest Service to develop a framework for future actions within the National Forest. – DuPont met with USDA-FS on June 7, 2006 to discuss path forward. – Future work will address both the Cabin Lake and Clover sites.

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33. June 7, 2005Former DuPont Barksdale Works33 Questions or comments?

34. June 7, 2005Former DuPont Barksdale Works34 Perchlorate Overview n Why are we looking for perchlorate at Barksdale? – A historical document identified in February of 2005 indicated that the former Barksdale plant manager was corresponding with a chemist in Chile about staffing. – This letter may indicate a that sodium nitrate from Chile was used for as a raw material for nitric acid production at Barksdale.

35. June 7, 2005Former DuPont Barksdale Works35 Perchlorate Overview n At this time, most naturally occurring sources of perchlorate appear to be geographically limited to arid environments. High natural perchlorate concentrations are found in Chilean caliche and some potash ores. – Sodium nitrate is leached from Chilean caliche to make fertilizers, among other products. n Chilean nitrate derived fertilizers were the primary fertilizers used in the United States until the 1960s. – Sodium nitrate (“soda nitre” or “Chilean saltpeter”) was formerly an important raw material for the production of nitric acid in the United States and elsewhere.

36. June 7, 2005Former DuPont Barksdale Works36 Perchlorate Overview n Preliminary results: – Preliminary laboratory results indicate that concentrations in groundwater surrounding the former nitric acid production area range between 0.033 to 150 parts per billion (ppb). – Perchlorate was not detected in the two potable wells sampled on-site.

37. June 7, 2005Former DuPont Barksdale Works37 Perchlorate Overview n EPA has established a 24.5 ppb limit in drinking water for perchlorate. – Perchlorate inhibits iodide uptake.