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Site Report: Tesoro Northstore #5

Site Name: Tesoro Northstore #5
Address: 9220 Lake Otis Pkwy, Anchorage, AK 99507
File Number: 2100.26.081
Hazard ID: 23719
Status: Cleanup Complete
Staff: No Longer Assigned, 9074655229 dec.icunit@alaska.gov
Latitude: 61.137214
Longitude: -149.834863
Horizontal Datum:NAD83

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

Benzene and BTEX contamination was encountered during the testing of the suitability for upgrading the UST's using cathodic protection in October of 1996. Another release was reported in April of 1997 caused by damage to the overfill catchment basin. During the removal of the two 8,000 gallon gasoline tanks, soil and groundwater contamination was encountered. Approximately 275 cubic yards of contaminated excavated soil was thermally remediated at Anchorage Soil Recycling. Groundwater monitoring was done quarterly with a continual decline in concentration levels. Updated 11-22-06 Alyce Hughey.

Action Information

Action Date Action Description DEC Staff
11/27/1996 Leaking Underground Storage Tank Release Confirmed - Petroleum LUST Site created in CSP for source area ID 77812 ADD; Gasoline contamination. Former Staff
11/27/1996 Site Added to Database Former Staff
2/11/1997 Leaking Underground Storage Tank Cleanup Initiated - Petroleum LCAU; Former Staff
11/20/1997 Update or Other Action ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: TESORO NORTHSTORE Former Staff
11/24/1997 Release Investigation Dept received the Phase I Release Investigation from RP's consultant. Former Staff
1/20/1998 Update or Other Action Had meeting with RP and consultant. Former Staff
2/17/1998 Leaking Underground Storage Tank Corrective Action Underway Dept received Workplan for 1998 actions. Former Staff
2/23/1998 Update or Other Action Dept received request from consultant for direct haul of contaminated soils-- approved same day. Former Staff
3/3/1998 Long Term Monitoring Established Dept received monitoring report for Nov 97 event. Former Staff
3/5/1998 Update or Other Action Dept reviewed and responded to Phase I RI, 98 Workplan and Nov Monitoring Reports. Former Staff
4/8/1998 Long Term Monitoring Established Dept received Feb 98 Monitoring Report. Former Staff
4/15/1998 Update or Other Action Dept reviewed and responded to Feb 98 Monitoring Report. Former Staff
5/4/1998 Update or Other Action Dept received and responded to, approving workplan amendments. Former Staff
5/6/1998 Update or Other Action Dept received SA/Closure Report. Former Staff
5/13/1998 Update or Other Action Dept reviewed SA/Closure Report and responded to consultant. Former Staff
7/20/1998 Update or Other Action Paul Pinard sent a letter approving the treated 377 tons of excavated and treated soils at Alaska Soil Recycling. Alyce Hughey
8/21/1998 Release Investigation Paul Pinard sent a review comments letter after reviewing the Phase II Release Investigation from Gilfilian Engineering, dated July 20, 1998. Alyce Hughey
12/23/1998 Update or Other Action Paul Pinard sent a letter commenting on the groundwater monitoring events, and did not approve the workplan dated December 14, 1998 for a CAP to be performed, felt it was not necessary. Alyce Hughey
1/28/1999 Update or Other Action Paul Pinard sent a letter with comments after reviewing the 1999 Workplans for the Tesoro Contaminated Sites. Alyce Hughey
3/25/1999 Update or Other Action Paul Pinard sent a conditional approval letter for the proposed 1999 Work Plan. Alyce Hughey
6/25/1999 Update or Other Action Paul Pinard sent a review comments letter after reviewing the March 1999 Monitoring Event. Alyce Hughey
9/15/1999 Update or Other Action Paul Pinard sent a review comments letter after reviewing the June 1999 Monitoring Report and the Well Search Report. Alyce Hughey
2/28/2000 Long Term Monitoring Established Received December 1999 Monitoring Event report. (also received monitoring report for Sept. 1999 earlier in year). Monica English
12/11/2000 Long Term Monitoring Established Received October 2000 Monitoring Event report. (previously rec'd April 2000 monitoring report) Monica English
9/25/2001 Underground Storage Tank Site Characterization or Assessment Received Confirmation Soil Boring Investigation report. Monica English
1/29/2002 Long Term Monitoring Established Received November 2001 Monitoring Event report. (previously rec'd April 2001 monitoring report) Monica English
6/13/2002 Update or Other Action ADEC SVE System Installation Workplan approval. Monica English
7/24/2002 Long Term Monitoring Established Received May 2002 Monitoring Event report. Monica English
11/1/2004 Document, Report, or Work plan Review - other April 2004 Monitoring event report. GW contaminant trends consistent with previous sampling. MW1 exceeds GCL for benzene. SVE remediation system continues to operate. Monica English
11/15/2004 Update or Other Action Staff attends annual environmental planning meeting with Tesoro and MWH to discuss potential work plan for 2005. Monica English
11/18/2004 Update or Other Action File number 2100.26.081 assigned and entered into the Fileroom DB and LUST DB. Alyce Hughey
2/18/2005 Update or Other Action ADEC issues conditional approval for the 2005 calendar year Corrective Action work plan. Monica English
11/15/2005 Update or Other Action Annual Environmental Planning meeting attended by ADEC, Tesoro, and MWH. Monica English
11/17/2005 Update or Other Action Approval issued for the 2006 calendar year work plan. Continued ground water monitoring will be conducted to track migration and trends of contaminants. Installation of confirmation soil borings are proposed. Pending the results from analyticals obtained from the confirmation soil borings a No Further Action determination may be requested. Monica English
7/12/2006 Document, Report, or Work plan Review - other Monica English sent a review comments letter after reviewing the Supplemental Work Plan for Confirmation Soil Borings. Alyce Hughey
10/9/2006 Update or Other Action Project manager changed from Monica English to Paul Horwath, per Paul Horwath. Alyce Hughey
11/22/2006 Update or Other Action Using Figure 1 from the April 2006 Monitoring Event Report, from Montgomery Watson Harza, dated August 2006, in conjunction with TopoZone Pro and Anchorage Live Maping, entered the coordinates for this site. Metadata includes No Topo Basemap, Black and White Aerial Photo, TopoZone Pro Street Maps, on a Medium Size Map, View Scale 1:9,840, Coordinate Datum NAD83. High degree of confidence in accuracy of location. Alyce Hughey
4/10/2007 Leaking Underground Storage Tank Corrective Action Underway Reviewed and approved MWH's Supplemental Work Plan for Chemical Oxidation Treatment, dated February 21, 2007. Paul Horwath
4/10/2007 Document, Report, or Work plan Review - other Reviewed MWH's October 2006 Confirmation Soil Boring Report Final, dated March, 2007. Nine soil borings were drilled and sampled. Benzene continues to exceed ADEC "migration to groundwater" soil cleanup levels, but the residual concentrations are now quite low, approaching the soil cleanup level. Low levels of benzene remain in one onsite GW monitoring well also, exceeding ADEC groundwater cleanup levels. Paul Horwath
8/6/2008 Document, Report, or Work plan Review - other Reviewed the MWH August 2007 Monitoring Event Report dated May 2008. MW-1 had a decrease in Benzene from the March 2007 monitoring event from 0.00426 mg/L to nondetect. The SVE system has been operating within normal limits and will remain in operation. Site conditions continue to improve. The areas of residual soil contamination identified in 2006 will be treated by calcium peroxide injections in September of 2007, and a report covering this treatment effort will be submitted to ADEC. Oversight review conducted by PHorwath 8/20/08. Alyce Hughey
9/24/2008 Document, Report, or Work plan Review - other Reviewed the April 2008 Monitoring Event Report, prepared by MWH, dated July 2008 for Paul Horwath, and provided a summary of the report for his review. With a slight increase in Benzene concentrations, below the ADEC groundwater cleanup levels that was found during this monitoring event, site conditions continue to improve with a consistent trend of undetected levels of Toluene, Ethylbenzene, Xylenes, and GRO since 2004. Alyce Hughey
9/26/2008 Document, Report, or Work plan Review - other Review MWH's April 2008 Monitoring Event Report and generate an e-mail to MWH requesting an explanation as to why the elevation of MW-6 would be 2.6' lower now than it was during the previous MW casing elevation survey. Possible error in elevation survey. Paul Horwath
10/22/2008 Document, Report, or Work plan Review - other Reviewed the July 2008 Confirmation Soil Boring Report, Final, dated August 2008, from MWH for Paul Horwath and provided him a summary of the report for his review and oversight. Low to moderate levels of benzene was detected above the ADEC soil cleanup level in all samples collected, except in SB-1 and SB-5. A considerably higher concentration of benzene was detected in Sample SB-5 at 9 ft bgs. The 2007 chemical oxidation treatment was not effective at bringing contamination below the soil cleanup levels at this site. Due to the type of soils, and the amount of material injected, along with the number of injections might be a contributing factor as to why the chemical oxidation treatment was not effective. If the technique is to be use again, a larger volume of peroxide injected over multiple events might yield better results. Alyce Hughey
10/22/2008 Document, Report, or Work plan Review - other Reviewed and discussed with Paul Horwath MWH's April 2008 Monitoring Event Report(Revised)from MWH's response to e-mail requesting explanation as to why the elevation of MW-6 would be 2.6' lower now than it was during the previous MW casing elevation survey. Response from MWH was MW-7 was erroneously surveyed and labeled as MW-6 during the April 2008 monitoring event. The data was removed from the report and the corrected sheets were provided. Alyce Hughey
8/12/2009 Document, Report, or Work plan Review - other Reviewed the May 2009 Monitoring Event Report, dated July 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. Site conditions are remaining stable with a slight detection of Benzene being detected in MW-1 that is below the groundwater cleanup levels. All monitoring wells tested since February of 2006 have remained below the groundwater cleanup levels. Residual soil contamination does remain above the soil cleanup levels according to the confirmation soil samples performed in 2008. MWH is drafting a work plan to be submitted to ADEC for approval to address the remaining soil contamination at the site. Alyce Hughey
8/25/2009 Document, Report, or Work plan Review - other Reviewed and approved the August 12, 2009 Work Plan for Excavation of Contaminated Soil, at the Former Tesoro Northstore #5, from MWH. Paul Horwath
9/15/2009 Offsite Soil or Groundwater Disposal Approved Approved the September 15, 2009 4:00 PM e-mail stating modifications to the original work plan approved by ADEC on August 25, 2009. The modifications to the original work plan are that the excavated soil that is determined by field screening methods to be "clean (uncontaminated)" will be hauled directly to Tesoro Northstore #11 for temporary storage. Once the test results are found to be below soil clean-up standards the soil will be landspread at Tesoro Northstore #11. However, if the test results indicate the soil is contaminated above SCL's then the soil will be hauled directly to ASR for Thermal Remediation. the excavated soil that is determined to be "contaminated" will be sent to ASR for Thermal Remediaiton. The estimated amount of anticipated soils to be excavated is 50 cubic yards. Paul Horwath
9/18/2009 Offsite Soil or Groundwater Disposal Approved Approved for approximately 30 cubic yards of soils to be excavated on 9-20-09 to be transported to ASR in Anchorage for thermal remediation. Paul Horwath
12/17/2009 Document, Report, or Work plan Review - other Reviewed the September 2009 Excavation Report, dated November 2009, from MWH for Paul Horwath. The excavation of approximately 68.51 tons of contaminated soil performed on September 20, 2009 in the area of the high benzene concentration detected in CSB-5 obtained in July of 2008 was successful. Benzene soil contamination does remain from 6.5 to 11 feet below ground surface in the area of the east, west and south sidewalls of the excavation, at concentrations of 0.0363 mg/Kg to 0.713 mg/Kg. Based on the findings of the excavation the remaining residual soil contamination appears to be confined to the dense, compact, silty soil associated with the glacial and stream deposits common to the site. A fourth quarter 2009 groundwater sampling event is planned for the site, and based on the findings of the sampling event, the site will be evaluated for cleanup complete with institutional controls in 2010. Alyce Hughey
3/11/2010 Conceptual Site Model Submitted ADEC received the March 4, 2010 Request for Cleanup Complete with Institutional Controls, prepared by MWH consultants, including a narrative-style conceptual site model. Paul Horwath
6/25/2010 Final Cleanup Report Reviewed Reviewed the September 2009 Excavation Report prepared by MWH, dated November 2009, involving the excavation and removal of approximately 68 tons of gasoline contaminated soil. This soil was all transported to Alaska Soil Recycling for thermal treatment and disposal. Paul Horwath
6/30/2010 Long Term Monitoring Complete As a condition of the Corrective Action Complete decision document, the groundwater monitoring wells must now be decommissioned, and no further groundwater monitoring will be necessary. Paul Horwath
6/30/2010 Cleanup Complete Determination Issued A corrective action comlete decision letter was issued. No formal institutional controls were required. Paul Horwath
11/3/2010 Document, Report, or Work plan Review - other Reviewed the Monitoring Wells and In-situ Remediation System Decommissioning Report, dated September 20, 2010, from MWH. MW/SVE-1, MW-2, MW-3, MW-4, MW-5, MW-6, MW-7, soil vapor extraction system and associated piping was decommissioned on August 22, 2010 according to ADEC guidance and approved monitoring well decommission plan. Alyce Hughey

Contaminant Information

Name Level Description Media Comments
BTEX Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Residual benzene concentrations are present between 2 and 15 feet below ground surface.

Control Type

Type Details
No ICs Required

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.
Document name File Size Document Date
Tesoro Northstore 5 Corrective Action Complete 6-30-10 285 KB

No associated sites were found.

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State of Alaska Department of Environmental Conservation

P.O. Box 111800
Juneau, AK 99811-1800
Phone: 907-465-5066
Fax: 907-465-5245
TDD: 800-770-8973
Physical Location: 410 Willoughby