RECEIVED Apri14, 2019 APR 0 5 2019 Ben Haller BUREAU OF Kansas Department of Health and Environment ENVIRONMENTAL REMEDIATION Bureau of Environmental Remediation Remedial Section/Site Remediation Unit I 000 SW Jackson Street, Suite 420 Approved with Comments Topeka, Kansas 66612-1367 Date(s) /3 1-J '1-12.. ~ 2..D/1 RE: STF Suspected Waste Area Characterization Report Former Coastal Refinery, El Dorado, Kansas Dear Mr. Haller: On behalf of El Paso Merchant Energy-Petroleum Company (EPME-PC), Stantec Consulting Services, Inc. (Stantec) submits this South Tank Farm (STF) Suspected Waste Area Characterization report presenting data to further delineate and characterize a waste-like material reported in the September 2009 Third Phase Environmental Investigation Report (Third Phase Investigation Report) for the former Coastal Refinery (Site) located in El Dorado, Kansas (Figure I). This work is being conducted as part of the Corrective Action Plan (CAP) called for in the Site Final Corrective Action Decision (CAD, November 20 16). In addition, during soil grading/earthwork completed in December 2018 to improve surface water drainage from a former STF bermed area, a second suspected waste are.a was discovered. Both areas are identified on Figure 2, they were investigated, and the findings are presented in this letter report. NORTH STF SUSPECTED WASTE AREA The North STF suspected waste area was identified in 2008 during the Third Phase Investigation. History Sixteen shallow borings were advanced (STFPSB-0 I through STFPSB-16) as part of the Third Phase Investigation to assess the extent of the buried material during pipeline removal activities. The borings shown on Figure 3 were installed using a Geoprobe® rig to a maximum depth of eight feet, transecting the area. Soil samples were collected continuously at each boring location, logged, and screened with a photoionization detector (PID) at one-foot intervals. One sample of the material from the most impacted boring, STFPSB-02, was collected and submitted for laboratory analysis for the Modified Skinner List volatile organic compounds (VOCs), semi­ volatile organic compounds (SVOCs), and metals; and total petroleum hydrocarbons - gasoline range organics (TPH-GRO) and TPH - diesel range organics (ORO). Elevated lead (2,020 milligrams per kilogram [mg/kg]), TPH-DRO (27,000 mg/kg), TPH-GRO (2,900 mg/kg) were detected. An excerpt of the Third Phase Investigation Report table that includes the STFPSB-02 Kinder Morgan, Inc., Environmental Remediation Department 2 orth Nevada Aven ue, Co lorado Springs, CO 80903 Mr. Ben Haller KDHE - BER April 4, 2019 Page 2 of5 laboratory data is included as Attachment I. The area of concern was estimated to have a possible aerial extent of approximately 2,000 square feet and a depth of approximately 5 feet (370 cubic yards). Based on this Third Phase Investigation Report, the July 2014 Final Corrective Action Study (CAS) and the November 2016 CAD selected alternative included further investigation and delineation of the area followed by removal and proper disposal of any waste-like material. As part of the Site CAP, the August 31 , 2018 STF Suspected Waste Area Characterization Work Plan was prepared. The Stantec field staff who conducted the investigation were interviewed and boring logs (Attachment 2) were reviewed. Areas of moderate soil vapor concentrations were encountered; however, only one location, STFPSB-02, had elevated concentrations of some petroleum hydrocarbons and metals of concern, and no soil boring logs indicated a waste-like material. Given this information, the area of concern was suspected to be significantly smaller than previously believed and/or not a waste, but rather impacted soil. 2019 Soil Boring and Field Screening Kansas One-Call notification and utility locates were completed and borings were advanced on January 3 and 4, 2019 using a hollow stem auger (HSA) to refusal. Samples were continuously cored and descriptions of the soil and material logged (Attachment 2). A sample was collected from every !-foot interval and field-screened using a PID. A sample for laboratory analysis was collected from the highest PlD or most visually impacted zone within each boring. Sample Locations Eight borings were installed, STFPSB-17 through STFPSB-24, as shown in Figure 3. STFPSB-17 was advanced near STFPSB-02, and the remaining borings were located 5 to I 0 feet away in an attempt to locate any nearby buried waste-like material. Photographs I and 2 (Attachment 3) show the STFPSB-17 core from 5 to 8 feet. Laboratory Analysis and Methods Based upon STFPSB-02 analytical results from 2008, all samples were analyzed for the Skinner List of volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), inductively coupled plasma (ICP) metals, TPH-Iow range hydrocarbons (LRH), TPH mid-range hydrocarbons (MRH), and TPH high-range hydrocarbons (HRH). In addition, one composite sample was submitted for waste determination, testing for: • Ignitability: Flash point (USEPA SWP846 Method I 0 lOA) • Corrosivity: pH less than 2 or greater than 12.5 (USEPA 9045C) • Reactivity: Reactive cyanide (USEPA SWP846 Method 9014) and sulfide (USEPA SWP846 Method 9034) Mr. Ben Haller KDHE-BER April 4, 2019 Page 3 of5 • Toxicity: Toxicity Characteristic Leaching Procedure (TCLP) Resource, Conservation, and Recovery Act (RCRA) metals (USEPA SWP846 Method 6010C), VOCs (USEPA SWP846 Method 8260C), and SVOCs (US EPA S WP846 Method 8270C) Laboratory soil analytical results are summarized in Table I and reports are included as Attachment 4. Waste characterization results by the Toxicity Characteristic Leaching Procedure (TCLP) are summarized on Table 2, and other waste characteristics (i.e. ignitability, corrosivity, and reactivity) are summarized on Table 3. Boring Abandonment and IDW Management All soil borings were completed on property owned by EPME-PC and did not intersect the groundwater; therefore, the sha ll ow soil borings were abandoned by placing soi l cuttings back into the hole. Bentonite was used at the top of the soi l borings to finish filling the open holes, no excess cuttings were piled near each boring. Data Evaluation No waste-like material was observed during the additional investigation work. Zones of elevated photoionization detector (PJD) readings were described as silty or clayey soil or weathered limestone with dark gray and black hydrocarbon staining and odor, a mid-range to heavy-end hydrocarbon. This is consistent with the 2008 soil boring logs, field observations, and laboratory data. Table I results show no RSK exceedances with the exception of lead, naphthalene, and TPH-MRH. (WC-02-COMP is a composite sample from the other study area). A composite sample, WC-0 1-COMP, from the each of the highest PID-intervals was submitted for hazardous waste determination. TCLP toxicity results in Table 2 are below standards, including lead, and most are below method detection limits (MDLs). This confirms the lead is not significantly leachable even under the extreme test conditions, and hence not a threat to groundwater under Site neutral pH conditions. Other hazardous characteristic results summarized in Table 3 are well within acceptable ranges. Recommendation The North STF material is impacted soil and shallow weathered limestone, not waste-like material. Lead is not readily leached, and the zone of impact is at least two feet below ground surface, limiting the risk of exposure. Remaining risk can be addressed through the Soil Waste Management Plan (SWMP) soil handling requirements and the Environmental Use Controls (EUCs). The material is otherwise similar to other impacted soil being managed in accordance with the CAP through natural source zone depletion (NSZD), long term monitoring (LTM) , and monitored natural attenuation (MNA). No additional action is proposed for this area. Mr. Ben Haller KDHE - BER April 4, 2019 Page 4 of5 SOUTH STF SUSPECTED WASTE AREA As previously discussed, during December 2018 soil grading/earthwork to improve surface water drainage from a former STF bermed area, a second suspected waste area was discovered as shown on Figure 2. An excavator was mobilized to investigate the depth and confirm the limits of the material. Photographs of the area and excavation are included in Attachment 3. The area of interest is approximately 12 feet across on the north end, tapering to 6 feet across on the south end, and approximately I 00 feet long. A test pit dug by the excavator uncovered a mix of soil, petroleum, and some concrete/metal/wood debris continuing to bedrock approximately 6 feet below the top of the material. (The former tank dike exists to the east and the waste pit dike continues around the remaining sides, so depths from top of dikes are greater). Using an average width of 9 feet, the area contains approximately 200 bank cubic yards (bey) of mixed soil-petroleum. The material is not identical to the Main Process Area (MPA) asphaltic materials but is a similar blend of heavy-end hydrocarbons and soil. When dry and cold, the material was found to be stable, supporting the weight of a person, but the presence of tar-like surface materials suggests the petroleum portion may be a viscous fluid when warmed and deeper material was a wet, thick slurry-like when excavated. Analytical Data Collection, Analysis, and Evaluation On January 8, 2019 a composite sample, WC-02-COMP, of 3 aliquots collected from the south, middle, and north sections of the area, was submitted for laboratory analysis like the North STF samples, including a sample for hazardous waste determination. Laboratory soil analytical results are summarized in Table I, and reports are included as Attachment 5. Waste characterization results by the TCLP are summarized on Table 2, and other waste characteristics (i.e. ignitability, corrosivity, and reactivity) are summarized on Table 3. Similar to the north area, Table I WC-02-COMP results indicate no RSK exceedances with the exception of benzene (instead of lead), naphthalene, and TPH-MRH.