1. Review of Work Plan for Leaded Gasoline Tank Bottom Disposal Pit Assessment and Interim Stabilization Measures Presented by The Great Plains/Rocky Mountain Technical Outreach Services for Communities

2. Report Organization n 1. Introduction n 2. Identification of LGTB disposal pit locations n 3. Remedial objectives n 4. Corrective measures n 5. Remediation n 6. Soil sampling procedures n 7. Documentation and reporting

3. Introduction n elements of the Site Remediation Program and RCRA Corrective Action Program combined to satisfy the intent of RCRA n assessment and remediation of groundwater not addressed in this report (will be addressed on a facility wide basis) n actions are voluntary in advance of Permit

4. Introduction n LGTB pits are identified as SWMUs n exact location of the pits have been difficult to find n a 1974 map found in Texaco archives in 1999 plots locations of 25 pits –preliminary testing shows that map appears to be correct

5. LGTB Disposal Pit Locations n location of 16 disposal pits is confirmed –by sampling and testing for high lead content in soil in suspected areas –sometimes corroborated by electromagnetic survey results n more investigation needed to determine location of 9 disposal pits

6. LGTB Disposal Pit Locations n example—Tank 19507 (pg. 2-6) –pit identified in 1984 report as west of tank; soil and electromagnetic investigations did not confirm –late 1999, confirmed exact location using the 1974 map and a backhoe; soil was different than surrounding soil –pit was excavated to bedrock; soil put in lined roll-off bins; 420 tons soil removed –sampling of soil from sidewalls of pit indicate no high lead levels remain –soil sent to EQ Landfill in Romulus, Michigan (records in Appendix I)

7. Remedial Objectives (pg. 3-1) n lead is the reason the LGTB disposal pits are SWMUs in the facility permit –lead is the chemical that will drive the cleanup of the pits

8. Remedial Objectives (pg. 3-1) n “Removal of all of the lead impacted soil from the LGTB pit areas will ensure that all of the organic constituent impacts which are associated with the LGTB pits have also been removed.” –Not necessarily true. Different compounds move through the soil at different rates. The organic constituents may have spread beyond the lead impacted area. (TOSC opinion)

9. Remedial Objectives (pg. 3-1) n observed organic compounds will be noted, investigated, and cleaned up as hydrocarbon impacted soil, as necessary n organic compounds will be addressed in area specific plans –These planned activities should cover any organics left in soil surrounding the pit excavations and alleviate TOSC concerns expressed in previous slide.

10. Corrective Measures n Options (pg. 4-1) –in-situ stabilization –excavation and onsite stabilization, thermal desorption and disposal –excavation and offsite stabilization/disposal –capping and natural attenuation n All options technically feasible –excavation and offsite stabilization/ disposal is the selected remedy

11. Remediation n Procedures (pg. 5-1) –backhoe to remove soil –impacted soil placed directly into roll-off bins –labeled as K052-impacted media –placarded, manifested, shipped offsite for treatment and disposal

12. Soil Sampling Procedures Describes n sampling locations –grid system for large excavations –bottom and sides of smaller excavations –minimum of 4 samples per excavation n sampling methods –containers, chain of custody, decontamination of equipment

13. Soil Sampling Procedures Describes n field screening –may screen for total organic vapor concentrations n laboratory analysis –excavation confirmation samples will be analyzed for modified Skinner List (Table 3) –standard analysis techniques

14. Documentation and Reporting Will include... n maps showing location of each pit n summary of assessment and cleanup procedures n figures and tables showing sample locations, screening and laboratory results n laboratory reports n description of procedures followed n manifests and land disposal certificates