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Site Report: Alyeska PS 09 Tank 190


Site Name: Alyeska PS 09 Tank 190
Address: Mile 258 Richardson Highway; Pump Station 9, Delta Junction, AK 99737
File Number: 330.38.122
Hazard ID: 25634
Status: Cleanup Complete
Staff: ,
Latitude: 63.930750
Longitude: -145.766253
Horizontal Datum:WGS84

We make every effort to ensure the data presented here is accurate based on the best available information currently on file with DEC. It is therefore subject to change as new information becomes available. We recommend contacting the assigned project staff prior to making decisions based on this information.

Problems/Comments

On 5/25/2010, during a scheduled maintenance shutdown of the pump station, a loss of power caused a command circuit to open the system relief valve and close the station blocking valves, which allowed crude oil to overflow through vapor vents at the top of Tank 190. The entire release involved an estimated 5,175 gallons of crude but was contained within the lined, secondary containment system, which has a total capacity of 104,500 barrels (4,389,000 gallons). Excavation of contaminated material was limited by concerns about tank foundation integrity, so contaminated soil was left in place. This material was found to contain gasoline range (GRO), diesel range (DRO), residual range organics (RRO), and benzene, toluene, ethylbenzene, and xylenes (BTEX) above Migration to Groundwater cleanup levels. A Soil Vapor Extraction (SVE) system was installed as close to the edge of the tank as possible. The configuration uses screened, 2" diameter Poly Vinyl Chloride (PVC) pipes layed out in six concentric circles (20' apart).

Action Information

Action Date Action Description DEC Staff
3/3/2011 Report or Workplan Review - Other Date of receipt of Pump Station 9 Tank 190 Crude Oil Release Contamination Assessment and Remediation Report. Report documents product recovery, contaminated soil delineation and characterization, removal of contaminated fill material above liner, and installation of a SVE. Additional SVE installation work is planned for 2011 with SVE startup scheduled for 2012. Appendix D contains the laboratory data and is available only electronically. Keather McLoone
3/30/2011 Spill Transferred from Prevention Preparedness and Response Program Spill transferred by PERP staff John Ebel. Spill no. 10309914501; spill date = 5/25/10; substance = crude oil; quantity = ~2,580 barrels / ~191,562 gallons; PERP file no. 140.02.055. Mitzi Read
4/1/2011 Site Added to Database A new site has been added to the database Mitzi Read
4/4/2011 Exposure Tracking Model Ranking Initial ranking with ETM completed for source area id: 79066 name: Alyeska PS 09 Tank 190 Mitzi Read
7/26/2011 Report or Workplan Review - Other Date of receipt of Pump Station 9 Tank 190 Remediation Work Plan and telephone communication with Alyeska regarding work planned for 2011. The tank work will be conducted prior to the work covered in the work plan. The area is on top of containment liners, will be "capped" by the tank, and will also be treated by the SVE system. There is inaccessible residual contamination below the north, east, and west perimeter of the tank. Contamination extends beneath the tank wall but the extent is unknown. Inside the tank, the wall base plate extends two or three feet inside the wall and cannot be undermined. The project will remove 24 inches of soil from the entire footprint of the tank beneath the base plate. This is approximately 3,000 cubic yards. This soil will be evaluated for contamination based on visual and odor. If there is any evidence of contamination, it will be stockpiled and remediated in accordance with the Contaminated Soil Stockpile Management Plan. It will also be sampled prior to stockpiling if the degree of contamination appears to represent potential hazardous waste. Soil without evidence of contamination, will be spread within the secondary containment or returned beneath the tank (i.e. it will not be used outside of the containment area). During the tank work, Alyeska will also hand excavate 10 locations within the tank down to the liner to verify the liner's integrity. The liner integrity work is being conducted in relation to compliance with 18AAC75.075 (Secondary Containment requirements…) rather than specifically in relation to contamination. However, it will provide another check for extent and degree of potential contamination. Unless significant/separate-phase contamination is encountered (i.e. has migration potential and/or will degrade the liner), the project will not excavate further toward the liner. Excavating deeper than 24” below the existing grade under the tank floor significantly increases the risk of damaging the liner, which will significantly delay the project and increase the risk of damaging the liner, which would then require more excavation to patch. This would also increase the likelihood of contaminant migration to the soil beneath the liner. SVE activity will include: testing soil vapor concentrations and air flow from the six SVE circuits; installing the aboveground portion of the system; and testing and balancing the system to determine optimal system operating configuration in preparation for the 2012 operating season. Keather McLoone
1/23/2012 Report or Workplan Review - Other Date of receipt of Contamination Assessment Report. During October 2011, Alyeska replaced the tank bottom as a corrosion prevention measure, which provided an opportunity for sampling. Field screening conducted every 10 feet along the tank's sidewall revealed a limited amount of conatamination under the tank. Analytical samples indicated that remaining contamination is below human health levels at concentrations up to 451 mg/kg GRO, 5,500 mg/kg DRO, 4,800 mg/kg RRO, 0.933 mg/kg benzene, 13.1 mg/kg toluene, and 9.55 mg/kg ethylbenzene. Alyeska plans to operate the SVE during 2012 to treat contamination along the tank's exterior. This work did not completely fall under the previous workplan. However, circumstances changed and the opportunity arose. PAHs were not included in the analytical suite, because these were not found above the most conservative criteria in the release assessment report. Keather McLoone
5/4/2012 Report or Workplan Review - Other Date of receipt of 2012 Remediation Work Plan. Activities planned include powering the SVE, repairing components as needed, and measuring soil vapor. A conditional approval with comment letter was sent in response. Keather McLoone
7/10/2012 Offsite Soil or Groundwater Disposal Approved Approved Alyeska to transport 25 cubic yards of contaminated soil generated during the May 2010 release event to OIT in Fairbanks for thermal treatment/remediation. Caveats include: post-treatment testing and reporting to ADEC for GRO/DRO/RRO/BTEX concentrations, restrictions against use as a base layer in wetlands or environmentally sensitive areas, and restrictions against disposal into surface waters. Richard Bernhardt
1/7/2013 Update or Other Action Updated coordinates based on Google Earth Imagery. Richard Bernhardt
2/13/2013 Report or Workplan Review - Other Reviewed the 2012 work report. On behalf of Alyeska, SLR retrieved two portable SVE blowers that were previously used at PS06 and PS09 and attached them to the SVE system that was already in place at this site. This configuration allowed 316.9 pounds of TPH-G to be recovered while operating between June 26 and October 8, 2012. Recovery rates decreased markedly as the season progressed until vapors only contained 5,400 mg/m^3 TPH-G on October 8, 2012. QA sheets included in work report. Richard Bernhardt
2/14/2013 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for Alyeska PS 09 Tank 190. The highest exposure category is now "De Minimis Exposure," and this site will be evaluated for closure. Richard Bernhardt
2/27/2013 Cleanup Complete Determination Issued By law, DEC is required to recover expenses incurred during cleanup, including staff oversight time. Current and former landowners may be liable for state cleanup expenditures. Alyeska's remediation efforts have successfully reduced contaminant levels below ADEC's most stingent cleanup levels, and no further characterization or remediation will be required. Richard Bernhardt

Contaminant Information

Name Level Description Media Comments
Benzene < Method 2 Most Stringent Soil

Control Type

Type Details
No ICs Required

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.

Missing Location Data

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