1. A New Risk-Based Approach to Establish Clean-up Levels for TPH David Nakles and Stephen Geiger ThermoRetec Consulting and Engineering Sara McMillen and Renae Magaw Chevron Research and Technology Company Jill Kerr Exxon Production Research Company Robert Sweeney Unocal

2. Acknowledgments §Nancy Comstock - Department of Energy: National Petroleum Technology Office §Harley Hopkins - American Petroleum Institute §John Harju - Gas Research Institute §George Deeley/ Ileana Rhodes - Equilon Enterprises, LLC §Michele Emerson - Chevron Research and Technology Company

3. Acknowledgments (Con’t) §H. Rodger Melton and Maged Hamed - Exxon Production Research Company §Paul Lundegard - Unocal §Deborah Edwards - Exxon Biomedical Sciences, Inc. §Greg Douglas and George Naughton - A.D. Little

4. Regulation of Environmental Impacts in the United States Evolving Risk-Based Approach §Using state-of-the-art science Goal: To protect human health and the environment by: §Developing cleanup standards based on: 1. Risk to human health 2. Expected land use

5. Benefits of the Change §Incorporates new science and methods

6. Form 4 Form 3 Form 2 Form 1 Benefits of the Change §Provides standardized but flexible approach

7. Benefits of the Change §Provides more effective site management

8. Benefits of the Change §Ability to use alternatives to aggressive remedial technologies in all types of settings

9. Presentation Objectives Describe risk-based method for determining acceptable concentrations of crude oil in soil §Describe elements of environmental risk §Present methods to assess risk of non-cancer health effects §Demonstrate application of methods to hypothetical E&P site l Identify range of acceptable concentrations for crude oil in soil l Confirm ability to use conventional measurement techniques

10. Elements of Environmental Risk Risk is the possibility that something bad might happen Risk  Hazard * Exposure * People Hazard Exposure People Risk

11. Assessing and Managing Risk at Crude Oil Sites Risk  Hazard * Exposure * People Hazard Exposure People Risk Ingestion Inhalation Skin Contact

12. l TPH measurement is not sufficient for hazard evaluation l Need method for understanding the composition of crude oil and its products Hazard Evaluation of Crude Oil l Estimated that over 100,000 individual compounds exist in crude oil l Toxicity of these compounds varies widely — no one compound can represent mixture

13. TPH Results Are Method Specific TPH Methods: Approximate Carbon Ranges Purgeable/Volatile/Gasoline Range, Modified 8015, Purge and Trap, GC Diesel Range, Modified 8015, Extraction, GC 418.1, Modified 418.1: Extraction, IR C2C2 C4C4 C6C6 C8C8 C 10 C 12 C 14 C 16 C 18 C 20 C 22 C 24 C 26 C 28 C 30 Gasoline Diesel Fuel/Middle Distillates Lube/Motor Oil, Grease

14. Problems with Using TPH for Assessing Risk TPH can be measured throughout nature…. …..and not all TPH is the same Dried Oak Leaves 18,000 mg/kg (1.8%) Crude Oil 618,000 mg/kg (61.8%) Grass 14,000 mg/kg (1.4%) Pine Needles 16,000 mg/kg (1.6%) Petroleum Jelly 749,000 mg/kg (74.9%)

15. Problem with Existing Cleanup Goals for TPH Different States 1 10 100 1,000 10,000 100,000 1,000,000 TPH Cleanup Level (mg/kg) Cleanup Levels Petroleum Jelly Gasoline Crude Oil

16. §Determine TPH composition §Determine risk-based screening levels (RBSLs) of hydrocarbon mixtures in soil §Has been implemented by several states (e.g., Louisiana, Michigan, Alaska,Texas, Ohio) Solution: Conservatively Estimate Human Health Risk Using Chemical Composition of TPH New methodology derived from the TPH Criteria Working Group (TPHCWG) — Established in 1995 by the USAF 2345

17. Preferred Option Risk Assessment Approaches for Petroleum Hydrocarbons C5C35 Indicator Approach BenzeneAnthracene Fraction Approach C5 58101216 35 21 6 C5-C8 C8-C16 C16-C35 Whole Product Approach C5C35 GasolineDiesel

18. Determining TPH Composition: Separate TPH into Fractions Separate based on chemical structure AromaticsAliphatics Toluene (C 7 H 8 or C 7 ) Octane (C 8 H 18 ) H|CH|C H — C C|C|HC|C|H C — H H — — H H — C — C — C — C — C — C — C — C — H H|H| H|H| H|H| H|H| |H|H |H|H |H|H |H|H H|H| |H|H H|H| |H|H H|H| |H|H H|H| |H|H

19. Determining TPH Composition: Further Separate TPH into 14 Fractions Further separate based on movement in the environment AromaticsAliphatics >C 6 -C 7 >C 7 -C 8 >C 8 -C 10 >C 10 -C 12 >C 12 -C 16 >C 16 -C 21 >C 21 -C 44 >C 5 -C 6 >C 6 -C 8 >C 8 -C 10 >C 10 -C 12 >C 12 -C 16 >C 16 -C 44 H|CH|C H — C C|C|HC|C|H C — H H — — H H — C — C — C — C — C — C — C — C — H H|H| H|H| H|H| H|H| |H|H |H|H |H|H |H|H H|H| |H|H H|H| |H|H H|H| |H|H H|H| |H|H

20. Why Did The TPHCWG Go To All This Trouble? Not all chemicals in crude oil........ move the same in the environment Mobility Carbon Number

21. Adapting the TPHCWG Method for Crude Oil §Crude oils can have 60 to 70% >C 35 §Modified extraction, separation, and GC detection method l GC extended to C 44 compounds l Determined C 44+ fraction

22. Analytical Capability Now Exists to Categorize >85% of Crude Oil Compounds into Fractions 123456789101112131415 0 10 20 30 40 50 60 70 80 90 100 Mass Balance % GC <C6 >C44 Different Crude Oils Diesel

23. Comparison of Composition of Different Crude Oil Products 0 100,000 200,000 300,000 400,000 500,000 600,000 700,000 800,000 900,000 Concentration (mg/kg) TPH Fractions Aliphatics Aromatics Gasoline Mineral Oil Vaseline Crude Oil >C 6 -C 7 >C 7 -C 8 >C 8 -C 10 >C 10 -C 12 >C 12 -C 16 >C 16 -C 21 >C 21 -C 44 >C 5 -C 6 >C 6 -C 8 >C 8 -C 10 >C 12 -C 16 >C 16 -C 44 >C 44

24. Assignment of Toxicity to TPH Fractions §Toxicity data assigned to each fraction of TPH based on available animal toxicity studies §Animal toxicity studies are the same as used by the U.S. EPA

25. Representative Fraction Toxicity: C 5 to C 44+ (Non-Carcinogens) AromaticAliphatic 5.0 — Oral 18.4 — Inhalation0.04 — Oral 0.02 — Inhalation 0.1 — Oral 1.0 — Inhalation 0.03 — Oral2.0 — Oral Fraction-Specific RfDs/RfCs (mg/kg/day) 0.03 — Oral2.0 — Oral0.03 — Oral0.8 — Dermal Range >C 5 to C 6 aliphatic >C 8 to C 10 >C 10 to C 12 >C 12 to C 16 >C 16 to C 21 >C 21 to C 35 >C 35 to C 44 >C 44+ >C 6 to C 8 aromatic 0.2 — Oral 0.4 — Inhalation

26. Potential Routes of Exposure for Crude Oil Release at Typical E&P Sites Groundwater Impacted shallow soil Drinking water well Vapors Hazard People Exposure

27. Limiting pathway = surface soil for Vaseline ®, diesel, & crude oil Limiting pathway = soil leaching to groundwater for gasoline Non-Carcinogenic TPH RBSLs for Hydrocarbon Mixtures 0 20,000 40,000 60,000 80,000 100,000 RBSL, TPH (mg/kg) Vaseline ® Crude Oil 1800 mg/kg Non-Residential Sites Vaseline ® = 1,000,000 mg/kg Diesel Gasoline

28. 3 10 9 1 8 2 2 3 3 1 2 1 3 Non-Residential TPH RBSLs for Crude Oil in Soils Around the World 05101520253035404550 API Gravity 0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 TPH Non-Residential Surface Soil RBSL, mg/kg soil Upper Limit of Existing State Clean-Up Levels

29. Comparison of Crude Oil Composition of Study Samples to World-Wide Sample Set 50% 100% Saturates 50% 100% Resin + Asphaltenes Aromatics 100% Study Samples PERF 97-08 51 Oils and 6 Soils World-Wide Sample Set 636 Crude Oils Frequency Distribution World Oils

30. Conclusions Regarding Risk-Based Approach to E&P Site Management §Protects human health §Uses a rigorous state-of-the-art scientific process §Provides standardized approach §No need to analyze all sites using new analytical technique, but can rely on existing conventional TPH measurement techniques

31. Commonly Asked Questions §Why have cancer health effects not been addressed? §Why have ecological risks not been addressed? §Do we need to analyze more oils produced in our state?