Former DuPont Barksdale Works Project Update December 14, 2006 Great Lakes Visitors Center DuPont CRG

December 14, 2006Former DuPont Barksdale Works2 DuPont Company Representatives n Brad Nave – Project Director, DuPont Corporate Remediation Group n Jon Hammerberg – Senior Project Engineer, URS Corporation

December 14, 2006Former DuPont Barksdale Works3 Purpose of Meeting n Provide an update on site priorities and public commitments n Provide an update on work completed in 2006 and preliminary results n Discuss next steps

Barksdale Project Priorities and Commitments Review Brad Nave

December 14, 2006Former 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

December 14, 2006Former 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

December 14, 2006Former DuPont Barksdale Works7 Alternative Water Supply n Alternative Water Supply – To date, DuPont has been billed $115.6M and paid over $114.3M in related water supply costs to Washburn n Managing invoices, supply, and maintenance with Washburn

December 14, 2006Former DuPont Barksdale Works8 Home Value Protection Plan Home Value Protection Program has expired. – DuPont fulfilled all commitments and obligations n Last property (vacant lot) sold on June 23, 2006

2006 Site Investigation Jon Hammerberg

December 14, 2006Former DuPont Barksdale Works Site Investigations n Purpose of investigations: – Evaluate suitability of selected site areas for recreational use – Continue characterizing former production areas – Prioritize areas for future activities

December 14, 2006Former DuPont Barksdale Works Site Investigations n 800 samples from 4 geographic focus areas – Northern Production Area: (274 acres) site of former manufacturing and support operations – Northern Grid Area: (305 acres) lightly or undeveloped grounds inside the plant fence – Southern Area: (443 acres) product storage and undeveloped grounds inside the plant fence – Off Site Areas: (117 acres) residential and undeveloped grounds outside the plant fence

December 14, 2006Former DuPont Barksdale Works Site Investigation Map

December 14, 2006Former DuPont Barksdale Works13 Northern Area Investigation n Continued site characterization via – Trenching in former production areas – Discrete soil sampling at biased locations – Grid sampling generally in undeveloped areas – Geophysical survey of waste sites – Clearing (4.3 miles of new roads, 17 miles cleared) – Installation of 6 wells and interior groundwater sampling – Surface water and sediment sampling n Recovered and disposed TNT during investigation – ~2,000 pounds of TNT recovered to date – ~500 pounds recovered in 2006 n Evaluated perchlorate distribution in groundwater and soils

December 14, 2006Former DuPont Barksdale Works14 n Insert. Northern Area Investigation Maps

December 14, 2006Former DuPont Barksdale Works15 Southern Area Investigation n Continued site characterization – Supplemental sampling in areas where elevated concentrations of inorganic constituents were detected in 2005 n Discrete soil sampling at biased locations n Grid sampling

December 14, 2006Former DuPont Barksdale Works16 n Insert. Southern Area Investigation Map

December 14, 2006Former DuPont Barksdale Works Investigations Findings n Findings in undeveloped areas: – Large portions of the northern and southern undeveloped areas are acceptable for current recreational use n Approximately 438 of the 443 acres in the southern area are below site-specific recreational screening levels n Grid locations that exceed site-specific screening levels are principally confined to roadways and railroad beds n Arsenic responsible for most of the risk in the south n Area-wide cumulative risks within frequently used southern transportation corridors are in acceptable range for current use n Explosive compounds do not significantly contribute to overall risk in the southern area n Approximately 300 of the 305 acres within the northern gridded area appear to be acceptable for the current recreational use based on preliminary data evaluation

December 14, 2006Former DuPont Barksdale Works18 n Insert map 2006 S Risk & Corridor

December 14, 2006Former DuPont Barksdale Works19 n Insert maps/pictures of issues/findings. Draft Northern Area Undeveloped Area Investigation Results 1.Does not include biased samples 2.Results compared to site-specific recreational RCLS

December 14, 2006Former DuPont Barksdale Works Investigations Findings n Findings in production or waste areas – 18 of 21 areas on site have been investigated; the 3 yet to be evaluated potentially contain nitroglycerin and require different sampling procedures. – Products visible at the surface in 2/3rds of the areas evaluated and in the subsurface (> 2ft bgs) in half of the areas evaluated – Products are generally encountered along former process buildings and ditches; some located beneath building slabs – Product found in five buried waste and debris deposits (0.5 to four acres in size) located across the site – Potential asbestos containing material visible in 5 of the 18 areas evaluated

December 14, 2006Former DuPont Barksdale Works21 Perchlorate n Concentrations in groundwater onsite range between non-detect (at 0.01) to 1,200 parts per billion n The majority of the boundary groundwater results were less than 1 ppb – Three exceptions are observed downgradient of former burning ground south of Barksdale Village and north of Boyd’s Creek. East of HWY 13 perchlorate was detected at 250 ppb in groundwater n Perchlorate was not detected in the two potable wells sampled on-site n Concentrations in soil (ranged from non-detect to 2.2 mg/Kg) are below the residential screening value (55 mg/Kg)

December 14, 2006Former DuPont Barksdale Works22 n Insert maps/pictures of issues/findings.

Path Forward Brad Nave

December 14, 2006Former DuPont Barksdale Works24 Near Term Path Forward n Complete Current Conditions Report n Continue investigation – Production areas n Follow-up in previously investigated areas n Characterization of areas previously not investigated – Three dynamite/ nitroglycerine areas n Continue to understand NX distribution and contribution to risk – Northern Undeveloped Areas n Continued investigation and risk screening as determined by output of 2006 data evaluation n Meet commitments regarding municipal water supply n Research at GA Tech and on-site n Share results with WDNR and community members

Chequamegon-Nicolet National Forest Update Brad Nave

December 14, 2006Former DuPont Barksdale Works Chequamegon National Forest Work n National Forest Service contacted DuPont in April 2006 regarding two reported former detonation cladding sites n DuPont and the Forest Service developed a framework for future actions and the technical approach for a geophysical investigation at both sites n Field work begun in October to delineate the extent of metallic debris at the Clover and Cabin Lake sites n Delineation of debris completed at the Cabin Lake site n Debris delineation partially complete at the Clover site, work will resume in 2007 when weather allows

December 14, 2006Former DuPont Barksdale Works27

December 14, 2006Former DuPont Barksdale Works Cabin Lake Work n Insert map CABIN LAKE

December 14, 2006Former DuPont Barksdale Works Clover Results n Insert map OPERATORS STATION North Pad South Pad

December 14, 2006Former DuPont Barksdale Works Chequamegon National Forest Work n Continue delineating metal at the Clover site n Report 2006 findings for both sites n Work with the Forest Service to develop and execute a soil sampling program at both sites

December 14, 2006Former DuPont Barksdale Works31 Questions or comments?