1. Hillcrest Community Environmental Investigation No Conflict of Interest Geo Strata is not affiliated with and does not hold contracts with the oil & gas refining industry. Geo Strata is not affiliated with and does not hold contracts with the oil & gas refining industry. March 25, 2010 Texas Commission on Environmental Quality Geo Strata Environmental Consultants, Inc.

2.  Founded in San Antonio, Texas in 1991  Certified Woman-Owned Small Business  Main Offices are located in San Antonio  TCEQ Registered Corrective Action Specialist and Texas Licensed Geoscience Firm  TCEQ PST Contractor for 8+ years  70% of current workload - Government Entity clients  30% of current workload – Private Clients (primarily small business) Geo Strata Geo Strata Staff Includes: Geologists Hydrogeologists Environmental Scientists Field Technicians Support Staff

3. Project Organization Chart Michael Honeycutt TCEQ Project Sponsor Neeraja Erraguntla TCEQ Project Toxicologist Omar Valdez TCEQ Project Manager Cheri Krieg Geo Strata H&S Officer Suzanne Green Geo Strata Project Manager Steve Thornley Beacon Environmental Services Laboratory Manager Taryn Scholz Quality Assurance Associates QA Specialist

4. Hillcrest Phase 1 Conduct Passive Soil Vapor Survey Goal: To identify optimal locations for permanent monitor wells Typical Installation Set-up

5. Quality Assurance - Installation & Removal Activities All samples will be installed and collected by experienced Scientist(s) and Technician(s) All samples will be installed and collected by experienced Scientist(s) and Technician(s) Using standard methods and procedures specified in the Field Sampling Plan (FSP). Using standard methods and procedures specified in the Field Sampling Plan (FSP). Custody records and custody seals will be used. Custody records and custody seals will be used. Show control during sample transfer and to maintain the security and integrity of samples. Show control during sample transfer and to maintain the security and integrity of samples. Each sample will be collected in duplicate. Each sample will be collected in duplicate. In the event that any problem is encountered with the first analysis. In the event that any problem is encountered with the first analysis. Non-disposable equipment will be decontaminated between each sample. Non-disposable equipment will be decontaminated between each sample.

6. Independent Data Review Two partners (Dr. Donald A. Flory and Ms. Taryn G. Scholz) in business since 1984 Two partners (Dr. Donald A. Flory and Ms. Taryn G. Scholz) in business since 1984 Hired as a subcontractor through Geo Strata, but does not answer to Geo Strata, TCEQ, or the laboratory Hired as a subcontractor through Geo Strata, but does not answer to Geo Strata, TCEQ, or the laboratory Experience includes review and validation of data for over 10,000 samples from all types of sites (federal Superfund, Texas Superfund, TRRP, Louisiana RECAP, various EPA Regions) Experience includes review and validation of data for over 10,000 samples from all types of sites (federal Superfund, Texas Superfund, TRRP, Louisiana RECAP, various EPA Regions) Performed by QAA, L.L.C. (Quality Assurance Associates) www.qaallc.com

7. Quality Control Samples - Field Ambient field blanks (minimum two for the event) – PSG sampler exposed to air just like samples during installation and retrieval. Used to determine if samples are affected by exposure to ambient air during installation or retrieval Equipment rinsate blanks (one per day) – laboratory grade water poured over the borehole drilling equipment. Used to determine if the decontamination of borehole drills was adequate to avoid cross contamination between samples

8. Quality Control Samples – Field Trip blanks (one per shipment) – PSG sampler (unopened) stored and transported with samples during installation and retrieval. Used to assess the potential introduction of contaminants from sample containers or during the transportation and storage procedures Field duplicates (one per 10 samples) – second set of adsorbent cartridges collected simultaneously with a sample and transported in same sample vial Used to assess the precision of the sample collection and analytical procedures

9. Quality Assurance - Sample Analysis All samples will be analyzed by an experienced laboratory, dedicated to PSG analyses, that has a quality assurance program and proficiency testing program that meets NELAC requirements. All samples will be analyzed by an experienced laboratory, dedicated to PSG analyses, that has a quality assurance program and proficiency testing program that meets NELAC requirements. Beacon Environmental Services www.beacon-usa.com Beacon Environmental Services www.beacon-usa.com A rigorous, EPA-approved analytical method (SW-846 8260) will be used that uses GC/MS instrumentation, internal standard quantitation, and five-point calibration to produce definitive data with low detection levels (1-5 ng) A rigorous, EPA-approved analytical method (SW-846 8260) will be used that uses GC/MS instrumentation, internal standard quantitation, and five-point calibration to produce definitive data with low detection levels (1-5 ng) A full target analyte list of approximately 40 VOCs will be reported including BTEX, chlorinated hydrocarbons, and PAHs (Naphthalene and 2-Methylnaphthalene) A full target analyte list of approximately 40 VOCs will be reported including BTEX, chlorinated hydrocarbons, and PAHs (Naphthalene and 2-Methylnaphthalene) A complete data package including all required reportable data plus laboratory review checklists and necessary exception reports will be submitted. A complete data package including all required reportable data plus laboratory review checklists and necessary exception reports will be submitted.

10. Quality Control Samples - Laboratory Laboratory blanks (one per 20 samples) – clean adsorbent cartridges that are prepared and analyzed just like the samples Laboratory blanks (one per 20 samples) – clean adsorbent cartridges that are prepared and analyzed just like the samples Used to determine if samples are affected by any contamination introduced in the laboratory Used to determine if samples are affected by any contamination introduced in the laboratory Laboratory control samples (one per 20 samples) – clean adsorbent cartridges that are spiked with a known amount of target analytes and then prepared and analyzed Laboratory control samples (one per 20 samples) – clean adsorbent cartridges that are spiked with a known amount of target analytes and then prepared and analyzed Recoveries are used to determine accuracy of analysis on a clean sample matrix Recoveries are used to determine accuracy of analysis on a clean sample matrix

11. Quality Control Samples - Laboratory Matrix spike/matrix spike duplicate samples (one per 20 samples) – Samples that are spiked with a known amount of target analytes and then prepared and analyzed. Matrix spike/matrix spike duplicate samples (one per 20 samples) – Samples that are spiked with a known amount of target analytes and then prepared and analyzed. Recoveries are used to determine accuracy of analysis on the site sample matrix Recoveries are used to determine accuracy of analysis on the site sample matrix Surrogates (three used for every sample) – Deuterated compounds that are added to each sample. Surrogates (three used for every sample) – Deuterated compounds that are added to each sample. Recoveries are used to determine accuracy and validity of each analysis Recoveries are used to determine accuracy and validity of each analysis Internal standards (four used for every sample) – Deuterated compounds that are added to each sample and used to provide standardized quantitation. Internal standards (four used for every sample) – Deuterated compounds that are added to each sample and used to provide standardized quantitation. Recoveries are used to monitor matrix effects and show any loss in instrument sensitivity Recoveries are used to monitor matrix effects and show any loss in instrument sensitivity

12. Independent Data Review Review includes: Verifying that laboratory data package includes all required data Verifying that laboratory data package includes all required data Assuring that proper custody procedures and sample handling procedures have been used Assuring that proper custody procedures and sample handling procedures have been used Confirming that appropriate analytical methods and reporting procedures have been used Confirming that appropriate analytical methods and reporting procedures have been used Verifying that all QC samples (blanks, spikes, duplicates, etc.) have been included at the required frequency Verifying that all QC samples (blanks, spikes, duplicates, etc.) have been included at the required frequency Evaluating the results of the QC samples against criteria established in the FSP Evaluating the results of the QC samples against criteria established in the FSP Determining the effect of any QC deficiencies on the data quality Determining the effect of any QC deficiencies on the data quality Qualifying the data to indicate potential biases (if minor QC issues) or rejection (if significant QC issues) Qualifying the data to indicate potential biases (if minor QC issues) or rejection (if significant QC issues)

13. Thank You We look forward to assisting the TCEQ and the Hillcrest Community during this phase of assessment.