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Site Report: Tesoro - Northstore #53 USTs 1 & 2

Site Name: Tesoro - Northstore #53 USTs 1 & 2
Address: 1601 East Parks Highway, Wasilla, AK 99687
File Number: 2265.26.007
Hazard ID: 23539
Status: Cleanup Complete
Staff: No Longer Assigned, 9074655229 dec.icunit@alaska.gov
Latitude: 61.577700
Longitude: -149.410300
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

Soil contamination of 9,700 mg/kg GRO, 140.0 mg/kg Benzene, and 4,240.0 mg/kg BTEX was encountered during a site investigation/assessment, after one of the two 10,000 gallon underground storage tank failed a tank tightness test done in 1994. Approximately 355.94 tons of contaminated soil was excavated and treated at Clean Soils Alaska. Long term monitoring was established, and a Soil Vapor Extraction System was installed and utalized for treatment of contaminated soil, and Oxygen Releasing Compound Injection System was utalized for groundwater. Updated 1-17-07 Alyce Hughey.

Action Information

Action Date Action Description DEC Staff
8/3/1994 Leaking Underground Storage Tank Release Confirmed - Petroleum LUST Site created in CSP for source area ID 77807 ADD; Former Staff
8/3/1994 Site Added to Database Former Staff
9/15/1994 Update or Other Action RPL3; Issued a Responsible Party Determination and Action Request letter to FDIC. Former Staff
12/10/1994 Leaking Underground Storage Tank Cleanup Initiated - Petroleum LCAU; LUST corrective action underway. Former Staff
8/30/1995 Leaking Underground Storage Tank Corrective Action Underway CAPR; Reviewed an UST Release Investigation. The boring/ monitor well locations may be slightly adjusted due to the presence of buried utilities. The site plan is approved provided that the locations are approximately the same (to provide adequate spacing to determine water table gradient). If contamination has migrated off-site, additional monitor wells will have to be installed. Former Staff
10/11/1995 Release Investigation RELR; Reviewed a Phase 2 Site Assessment Plan. The well to be located between MW-2 and MW-3 is in the upgradient direction and is not specifically needed at this time. A desire to install the well anyway was expressed and the department does not object to its installation. Former Staff
1/26/1996 Underground Storage Tank Site Characterization or Assessment SA1A; Reviewed a site assessment report. GW flow direction ambiguous. Need more refined information on GW monitoring as well as a schedule. Former Staff
3/12/1996 Release Investigation SA2A; Reviewed a TTT site assessment. The benzene level in well S1 was above allowable limits. Further assessment efforts are required. Submit a site assessment plan. Former Staff
3/22/1996 Leaking Underground Storage Tank Corrective Action Underway CAPA; Reviewed and approved, with provisions, a corrective action plan. GW treatment in the vicinity of monitor well #1 is OK. Former Staff
5/10/1996 Update or Other Action RI; Reviewed an UST Dispenser Release Site Investigation report. Former Staff
6/17/1996 Update or Other Action Mike Krieber sent a review comments letter after reviewing the Ground Water Monitoring Report from Hart Crowser, dated April 9, 1996. Alyce Hughey
7/8/1996 Long Term Monitoring Established Long Term groundwater monitoring began in 1996. Paul Horwath
7/24/1996 Update or Other Action UPD; Reviewed a site monitoring report. Higher reported contamination levels could be an indication of a continuing release into GW or a sign of seasonal water table fluctuation. Former Staff
3/5/1997 Update or Other Action Steve Bainbridge sent a letter with a brief synopsis of the status of the site after the Annual Meeting. Alyce Hughey
3/24/1997 Update or Other Action Mike Krieber sent a letter with review comments after reviewing the November 1996 Monitoring Report from Gilfilian Engineering, dated January 8, 1997. Alyce Hughey
7/8/1997 Offsite Soil or Groundwater Disposal Approved ADEC approval to transfer soils to Clean Soils in Anchorage was approved two different times in the late 1990s. Paul Horwath
7/31/1997 Update or Other Action Paul Pinard for Mike Krieber sent a letter with review comments after reviewing the March 1997 Monitoring Report, from Gilfilian Engineering, dated May 23, 1997. Alyce Hughey
8/25/1997 Update or Other Action Mike Krieber sent a conditional approval letter for the Soil Excavation, Transportation, and Treatment Plan during the UST Closure. Alyce Hughey
11/20/1997 Update or Other Action ADEC sends Notification of Intent to Cost Recover Letter to Current Owner: TESORO NORTHSTORE Former Staff
2/17/1998 Update or Other Action Dept completed review and responded to SA Report, received from the consultant on 12/18/97. 357 tons of contam. soils were excavated and hauled to Clean Soils for treatment. Two 10,000 gal tanks were removed and piping for an SVE system was installed. A pilot test on this system is planned. Former Staff
3/9/1998 Update or Other Action Dept completed review and issued a conditional approval of the proposed workplan for 1998, submitted by consultant on 2/13/98. Former Staff
4/16/1998 Update or Other Action Dept completed review of report on SVE pilot study and approved system design. Former Staff
5/4/1998 Update or Other Action Paul Pinard sent an approval letter for the 1998 Workplan, after reviewing the April 28, 1998 letter of response. Alyce Hughey
6/24/1998 Update or Other Action Paul Pinard sent a letter of response after reviewing the May 26, 1998 Well Search, from Gilfilian Engineering. Alyce Hughey
10/6/1998 Update or Other Action Paul Pinard sent a review comments letter after reviewing the June 1998 Monitoring Event Report, dated September 14, 1998, from Gilfilian Engineering. Alyce Hughey
12/28/1998 Update or Other Action Paul Pinard sent a review comments letter after reviewing the March 1998 and September 1998 Monitoring Events Report, dated October 9, 1998 from Gilfilian Engineering. Alyce Hughey
3/9/1999 Update or Other Action Paul Pinard sent a review comments letter after reviewing the 1998 Annual Monitoring Report, dated February 17, 1999, from Gilfilian Engineering. Alyce Hughey
4/26/1999 Update or Other Action Paul Pinard sent a review comments letter after reviewing the February 1999 Monitoring Event Report dated March 16, 1999 from Gilfilian Engineering. Alyce Hughey
7/22/1999 Update or Other Action Paul Pinard sent a review comments letter after reviewing the May 1999 Monitoring Event Report, dated June 29, 1999 from Gilfilian Engineering. Alyce Hughey
8/26/2002 Update or Other Action Monica English sent an approval letter to install an air sparge system after reviewing the May 2002 Monitoring Event & Air Sparge Pilot Testing Report, dated June 14, 2002 from Gilfilian Engineering. Alyce Hughey
1/14/2004 Leaking Underground Storage Tank Corrective Action Underway Approval for 2004 Work plan. Monica English
11/3/2004 Document, Report, or Work plan Review - other April 2004 Monitoring Event Report. GW contaminant trend consistent with previous sampling. Monitor well SVE2 exceeds GCL for benzene. The SVE/AS remediation system was restarted following a 90-day rebound period. Contaminant levels in SVE2 documented. Monica English
11/22/2004 Update or Other Action July 2004 Groundwater Monitoring Event report received. Benzene levels continue to exceed the groundwater cleanup levels in SVE-1 and SVE-2. Monica English
11/22/2004 Update or Other Action File number 2265.26.007 assigned and entered into the Fileroom DB and LUST DB. Alyce Hughey
1/25/2005 Update or Other Action ADEC issues approval for the 2005 calendar year Corrective Action work plan. Monica English
11/22/2005 Leaking Underground Storage Tank Corrective Action Underway Monica English sent an approval letter for the proposed Corrective Action Work Plan for 2006. Alyce Hughey
10/9/2006 Update or Other Action Project manager changed from Monica English to Paul Horwath, per Paul Horwath. Alyce Hughey
1/17/2007 Update or Other Action Using Figure 1 from the May 2006 Monitoring Event Report, dated August 2006, from Montgomery Watson Harza, in conjunction with TopoZone Pro and the Matsu Web Site, entered the coordinates for this site. Metadata includes USGS Topo Map 1:24/K/25K, TopoZone Pro Street Maps, on a Medium Size Map, View Scale 1:25,000, Coordinate Datum NAD83. High degree of confidence in accuracy of location. Alyce Hughey
4/5/2007 Exposure Tracking Model Ranking Initial ETM ranking completed. Paul Horwath
9/27/2007 Update or Other Action ADEC issued approval to transport 110 gallons of petroleum contaminated soil from this site to ASR in Anchorage. ASR post-treatment analyses include BTEX. Paul Horwath
10/15/2007 Leaking Underground Storage Tank Corrective Action Underway Reviewed MWH's Supplemental Work Plan for Installation of Additional Sparge Wells, dated June 5, 2007. Two additional air sparge wells are to be installed to enhance groundwater treatment. Issued work plan approval e-mail. Paul Horwath
10/30/2007 Update or Other Action Provide a written response to ASR's request for a closure letter for contaminated soils received from this site. Paul Horwath
8/8/2008 Document, Report, or Work plan Review - other Reviewed the MWH October 2007 Monitoring Event and Air Sparge System Expansion Report dated May 2008. Groundwater concentrations remained the same in MW-1 (undetect for GRO & BTEX) compared to the last monitoring event. In SVE-1 Xylenes were detected below GCL's. Last monitoring event of SVE-1 detected levels of Benzene and GRO above GCL's and detected levels of Toluene and Zylenes below GCL's. Concentrations did not improve in SVE-2, (detected levels for Benzene below GCL's were detected in this monitoring event were levels showed undetect for BETX and GRO in the last monitoring event. Two additional Air Sparge wells were installed with the anticipation that the groundwater concentrations will improve. ADEC staff Paul Horwath checked this action entry on 8/15/08 for purposes of QA/QC. Alyce Hughey
11/6/2008 Document, Report, or Work plan Review - other Reviewed the April 2008 Monitoring Event Report, dated October 2008 from MWH for Paul Horwath and provided him a summary of the review for is oversight. Site conditions remain stable other than a change in the groundwater flow direction. Polynomial Regression and Kriging Techniques was used to confirm the groundwater flow direction, which showed groundwater bulges within the vicinity of the air sparge wells. Two additional air sparge wells were installed on October 30, 2007. Further monitoring events are needed to see if the groundwater flow direction remains the same after the addition of the two new air sparge wells. Alyce Hughey
1/30/2009 Document, Report, or Work plan Review - other Reviewed the October 2008 Monitoring Event Report, dated December 2008, from MWH for Paul Horwath and provided a summary of his review and oversight. Site conditions remain stable. There was detection of Benzene and Toluene in SVE-1 during this monitoring event, but remain below the groundwater cleanup levels. The groundwater flow direction is flowing with an easterly flow direction, which is more consistent with previous monitoring events. During the past two monitoring events the Soil Vapor Extraction System has been off upon arrival at the site, and further investigation into why the system may need to be performed. The pressure of the Air Sparge System was operating higher than normal and further investigation is planned to check into it during the next scheduled operation and maintenance of the remediation system. Alyce Hughey
3/25/2009 Conceptual Site Model Submitted Conceptual Site Model submitted within the Summary Report and Request for Clean-up Complete with Institutional Controls, from MWH, dated March 19, 2009. Paul Horwath
4/30/2009 Document, Report, or Work plan Review - other Reviewed the Summary Report and Request for Clean-up Complete with Institutional Controls, from MWH, dated March 19, 2009 for Paul Horwath, and prepared a summary for his review and oversight. Based on the data submitted additional information was requested for the soil sample data in the October 2007 Monitoring Event and Air Sparge System Expansion Report, and that the treatment systems be shut off for a period of 6 months prior to collecting a round of confirmatory groundwater quality samples from the treatment wells and the surrounding groundwater monitoring wells. Alyce Hughey
5/1/2009 Update or Other Action Performed an updated ETM ranking of the site in the Contaminated Sites database. Alyce Hughey
7/31/2009 Document, Report, or Work plan Review - other Reviewed the April 2009 Monitoring Event Report, dated June 2009, from MWH for Paul Horwath and prepared a summary for his review and oversight. Site conditions have remained stable. SVE-2 had a detection of Benzene above the groundwater cleanup levels after five years of it remaining either below the groundwater cleanup levels or non-detected. All other wells sampled have remained below the groundwater cleanup levels for the past couple of years. MWH is performing a 180 day rebound test starting May 7, 2009. They are planning on performing an intermittent sampling after 90 days to mitigate the risk of an extended shutdown during prime summer remedial season, and allow for the system to be restarted should the intermediate results indicate poor groundwater quality. Alyce Hughey
5/13/2010 Document, Report, or Work plan Review - other Reviewed the August / November 2009 Monitoring Events and Rebound Test Report, dated March 2010, from MWH for Paul Horwath. The groundwater quality has shown some minor decreases and increase after the 180 day rebound test performed; with Benzene being the only analyte being detected just above the groundwater cleanup levels at 0.00598 mg/L. The remediation systems were turned back on after the last sampling event and air samples taken contained GRO at 33.7 ppm and Toluene at 0.590 ppm indicating that a low amount of hydrocarbons are being removed from the remediation systems. Alyce Hughey
5/25/2010 Final Cleanup Report Reviewed Reviewed the August / November 2009 Monitoring Events and Rebound Test Report, dated March 2010, prepared by MWH. Paul Horwath
5/27/2010 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 77807 UST Systems. An additional ETM ranking update was performed by Paul Horwath on 7/7/10. Alyce Hughey
7/8/2010 Cleanup Plan Approved Various cleanup plans approved in 1998, 2002, 2003, 2005, etc. Paul Horwath
7/8/2010 Cleanup Complete Determination Issued A Corrective Action Complete decision letter was issued for this site. All remaining wells and underground treatment piping must be decommissioned and reported to ADEC. Paul Horwath
7/8/2010 Long Term Monitoring Complete Long Term Monitoring complete with the ADEC receipt and review of the August / November 2009 Monitoring Events and Rebound Test Report, dated March 2010, from MWH consultants. Paul Horwath
1/5/2011 Document, Report, or Work plan Review - other Reviewed the Monitoring Wells and In-situ Remediation System Decommissioning Report, dated November 18, 2010, from MWH. The remaining eight monitoring wells, (MW-1 through MW-8), three air sparge wells (AS-1 through AS-3), two soil vapor extraction wells (SVE-1 and SVE-2) and the associated remediation system piping were decommissioned according the ADEC “Monitoring Well Guidance” dated February 2009. Alyce Hughey

Contaminant Information

Name Level Description Media Comments
BTEX Between Method 2 Migration to Groundwater and Human Health/Ingestion/Inhalation Soil Benzene contamination may remain in soils 15 or more feet in depth, at these concentrations.
GRO < Method 2 Most Stringent Soil
BTEX < Table C Groundwater Benzene at less than 6 ug/L.
GRO < Table C Groundwater

Control Type

Type Details
No ICs Required

Requirements

Description Details
Advance approval required to transport soil or groundwater off-site.
Hazard ID Site Name File Number
26641 Tesoro Northstore #53 Surface Release 2265.26.038

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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