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Site Report: UNOCAL - Portage Bulk Plant 0604

Site Name: UNOCAL - Portage Bulk Plant 0604
Address: Mile 78.8 Seward Highway, Portage, Girdwood, AK 99587
File Number: 2113.38.001
Hazard ID: 2008
Status: Cleanup Complete
Staff: No Longer Assigned, 9074655229 dec.icunit@alaska.gov
Latitude: 60.818327
Longitude: -148.975013
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

In 1993, petroleum contamination of soil and groundwater was documented during a preliminary assessment adjacent to the site property. Up to 520 mg/kg GRO, 610 mg/kg DRO, and 1.2 mg/kg benzene was found in the soil samples collected. Up to 18 mg/l GRO, 9.8 mg/l DRO, and 0.17 mg/l benzene was found in the groundwater. The on-property drinking water well was sampled and found to be non detect for contamination. In 2001, nine soil borings were sampled and completed as monitoring wells at the site to help determine the nature and extent of the contamination. Up to 9,840 mg/kg DRO, 2,110 mg/kg GRO, and 2.19 mg/kg benzene was found in the soil. Up to 24 mg/l GRO, 8.54 mg/l DRO and 0.0241 mg/l benzene was detected in the groundwater. In 2002, thirteen test pits were sampled which had up to 5,840 mg/kg DRO, 4,090 mg/kg GRO, and 2.99 mg/kg benzene. Later in 2002, approximately 1,308 tons of contaminated soil was excavated and transported off site for thermal treatment. Confirmation sampling documented that only one small area near the cafe building foundation had contamination (1,590 mg/kg DRO) left above the most stringent (i.e., migration to groundwater) 18 AAC 75.341 clean up levels. Three monitoring wells were installed to replace the monitoring wells that were removed during the 2002 excavation of the contaminated soil. On October 13, 2003, a no further remedial action letter was issued by ADEC, that required long-term groundwater monitoring. On October 22, 2008 four soil borings were sampled to assess current soil contamination concentrations. These samples were all non-detect for DRO, GRO and benzene. On March 31, 2009 ADEC approved suspending groundwater monitoring at the site. On June 11, 2010, ADEC received documentation that the remaining onsite monitoring wells had been decommissioned in accordance with the approved plan.

Action Information

Action Date Action Description DEC Staff
1/21/1994 Site Characterization Report Approved (Old R:Base Action Code = SA1R - Phase I SA Review (CS/LUST)). Review of preliminary site investigations report by R&M Consultants for ADOT proposed upgrade and channelization project. Bill Petrik
2/14/1994 Site Added to Database DRO, GRO and BTEX. Bill Petrik
6/1/1994 Update or Other Action (Old R:Base Action Code = RPL1 - Initiate Dialog with RP). AG's office sent first of PRP letter series with information request to Gregory and Elaine Anderson (owners of Tidewater Cafe property) and Jerry Mason (UNOCAL Sales and Property Manager). Response requested within 30 days of receipt. Bill Petrik
4/30/1996 Site Ranked Using the AHRM Ranked by Shannon and Wilson. S&W
8/27/1998 Update or Other Action Date of letter from CSRP to Unocal requesting review of information as a PRP. Jim Frechione
5/10/2000 Site Ranked Using the AHRM Changed the GW Usage Value from 0.1 to 0.8. Eileen Olson
11/9/2000 Update or Other Action File review: visit GeoEngineers to view better air photo copies; visit Aeromap to view air photo negatives Eileen Olson
11/17/2000 Update or Other Action ADEC letter requesting site investigation, based on site history research and other file info; requested that Unocal respond within 30 days, and provide a schedule to complete site investigation as soon as possible and no later than the 2001 field season. Eileen Olson
3/16/2001 Update or Other Action Letter sent requesting site investigation within specific time frames, including notification to the department by April 23rd of whether Unocal will comply with requirements of the letter. Letter requires plan submittal by May 15, with characterization work complete by June 30, 2001. Eileen Olson
4/19/2001 Update or Other Action Received letter on April 23rd, dated April 19th, from Unocal agreeing to do site investigation, and requesting guidance regarding point of compliance and use of 10 times rule. Eileen Olson
4/27/2001 Update or Other Action Sent letter responding to Unocal's 4/19/01 letter and including the requested guidance. Eileen Olson
5/30/2001 Site Characterization Workplan Approved Staff approved a site characterization work plan. The plan proposes to investigate former fuel storage, piping and dispensing areas by drilling six borings to approximate depths of 10 to 15 feet, and collecting at least two soil samples from each boring for analysis, and completing the borings as 2-inch monitoring wells. An additional 5 to 7 drive point wells will be installed at locations to be determined by the consultant, based on the observations made during and after completion of the six monitoring wells. Eileen Olson
8/29/2001 Site Characterization Report Approved Received GeoEngineers report "Subsurface Site Investigation" documenting groundwater contamination by GRO and DRO above cleanup levels near a former gasoline dispenser island. Eileen Olson
9/24/2001 Site Characterization Report Approved Sent letter commenting on "Subsurface Site Investigation, Former Unocal Bulk Plant 0604, Portage, Alaska” dated August 24, 2001, which documented the installation of 9 monitoring wells and 6 Geoprobe implant wells. Soil and groundwater sampling were conducted as part of this project. Report focused on 10 times rule cleanup levels with out documenting that the requirements are fulfilled. Contamination was documented in the area around the former dispenser island, the former bulk tanks and by monitoring well MW-9. Requested a work plan be submitted by March 1, 2002 for work to be completed during the 2002 field season. Elizabeth Stergiou
2/6/2002 Meeting or Teleconference Held Met with Scott Widness and Liz Shen of GeoEngineers and Mark Brearly of Unocal to discuss the possibility of alternative cleanup levels for the site. Elizabeth Stergiou
3/5/2002 Update or Other Action Sent letter commenting on "Groundwater Use Survey" which requested to rule out groundwater as a drinking water source under 18 AAC 350 and use the 10X rule for soil cleanup levels. The request was not approved at this time due to lack of landowner consultation and lack of documentation to rule out groundwater as a drinking water source. Elizabeth Stergiou
4/2/2002 Update or Other Action Review of “Results of Ground Water Monitoring and Sampling, December 2001" dated March 15, 2002. The report documented the December 2001 groundwater monitoring event and January 2002 depth to groundwater measurements. The Department had no comments to offer at that time. Elizabeth Stergiou
5/20/2002 Update or Other Action Request remediation work plan based on conversation with the landowner, Elaine Anderson, who will not accept alternative cleanup levels. Unocal was given a deadline of June 31, 2002 to submit a workplan. Elizabeth Stergiou
7/10/2002 Update or Other Action Conditional approval of Supplemental Site Characterization Plan which was submitted July 8, 2002. Unocal was directed to submit a remediation work plan by June 31, 2002 as per the Department's May 20, 2002 letter. Elizabeth Stergiou
8/27/2002 Site Characterization Report Approved Supplemental Site Characterization report and Results of Ground Water Monitoring dated August 15, 2002 were received August 15, 2002. The Results of Ground Water Monitoring and Sampling report documented sampling of monitoring wells MW-1 – MW-9 for GRO, DRO and BTEX. Sample results identified remaining groundwater contamination in wells MW-1, with 0.071 mg/L benzene, 13.3 mg/L GRO and 3.60 mg/L DRO, MW-2 with 4.91 mg/L DRO and MW-3 with 1.73 mg/L DRO. The Department approved the transport of approximately 28 gallons of contaminated purge water to Alaska Pollution Control for treatment. The Supplemental Site Characterization report documented the excavation of thirteen test pits and analysis of soil samples for GRO, DRO and BTEX. Analysis of soil samples from test pits TP-8 and TP-9 showed fuel contamination remains in place to groundwater at a depth of 9 feet below ground surface. Maximum contaminant concentrations in the soil are 2.99 mg/kg benzene, 70.3 mg/kg ethylbenzene, 256 mg/kg toluene, 373 mg/kg xylenes, 4,090 mg/kg GRO and 5,840 mg/kg DRO. These reports, in addition to the previously submitted reports, have satisfied the requirements for site characterization in accordance with 18 AAC 75.335(c) and are approved. Elizabeth Stergiou
8/27/2002 Cleanup Plan Approved The Work Plan for Site Remediation proposes excavation and sampling of soil in three areas of this site and the installation and sampling of three groundwater monitoring wells with the objective of reaching site closure. An estimated 700 cubic yards of petroleum contaminated soil will be removed from the area surrounding MW-1, TP-8 and TP-9, approximately 25 cubic yards will be removed from the area surrounding MW-3, and approximately 20 cubic yards will be removed from the area surrounding MW-9. Contaminated soil will be temporarily stored on site in accordance with 18 AAC 75.370 until soil analysis results are completed and Alaska Soil Recycling (ASR) is able to accept the soil. The work plan has been approved with the following conditions: 1. Additional field screening to adequately characterize each wall and collect at least two analytical samples from each excavation, with one being collected from the floor of the excavation, at the locations with the highest field screening result. 2. Submit a diagram with the proposed location of the monitoring wells and location and results of confirmation field screening samples collected for each excavation. The transfer of approximately 700-1,200 cubic yards of contaminated soil to ASR’s soil treatment facility has been approved. Elizabeth Stergiou
10/29/2002 Cleanup Plan Approved Approved the Revised Work Plan Addendum for Soil Treatment October 28, 2002. The plan proposes treating approximately 1,535 cubic yards of petroleum contaminated soil with a Hot Air Vapor Extraction System (HAVE) at the Shelley Homestead, located at Mile 1.7 of the Portage Glacier Highway. Elizabeth Stergiou
9/23/2003 Update or Other Action Project Manager changed to Egbejimba. Beatrice Egbejimba
10/21/2003 Record of Decision A ROD containing site information, remedial activities, approved cleanup level and ADEC's decision was signed on 10/13/03. Beatrice Egbejimba
10/21/2003 Update or Other Action ADEC sent letter to Robert Shipley of UNOCAL with approval of reports entitled Remedial Activities and Soil Treatment. Both reports were received 4/24/2003. Beatrice Egbejimba
10/21/2003 Conditional Closure Approved ADEC reviewed the site information collected to date and evaluated the soil cleanup activities. Based on the information presented above, it is the Department’s determination that no further remedial action is required at this site. This determination is based on the following conditions: 1. The soil above the 18 AAC 75.341 Table B1 and B2 migration to groundwater cleanup levels has been removed except for one area near the building foundation. The soil (1,590 mg/kg DRO) exceeded the site cleanup levels of 230 mg/kg DRO but it is considered minor in extent and would be impracticable to remove because of its location. It does not pose a risk to human health because it is less than the ingestion and inhalation standards for this area and the groundwater does not appear to be impacted. 2. A ground water monitor plan in accordance with 18 AAC 75.345(h) should be developed that identifies the wells and frequency of sampling. The plan should be prepared and submitted to ADEC for review and approval. It should include a groundwater monitoring event in July 2004 to verify current water quality conditions and evaluate any trend in contaminant concentrations. If the monitoring indicates an increasing trend in contaminant levels, ADEC may require continued monitoring and assess the need for additional cleanup. However, a stable or decreasing trend may allow the monitoring frequency and locations to be reduced or discontinued. 3. An institutional control (established on the ADEC database) will identify the nature and extent of contamination remaining on site. This information is intended to inform any future owners/operators of the environmental status of the property so they are aware of environmental and/or safety requirements. 4. If future information indicates that contamination is present at levels that may pose a risk to human health or the environment, then additional investigative and/or cleanup action may be required. 5. The transport of soil or groundwater from this site requires prior ADEC approval in accordance with 18 AAC 75.325(i). Beatrice Egbejimba
10/24/2003 Institutional Control Record Established Soil containing up to 1,590 mg/kg DRO and 0.0311 mg/kg benzene at 7 feet below ground surface is still present beneath the Tidewater Cafe building in a one foot thick sand seam. Based on field observations an estimated 6 foot wide section of that sand seam is contaminated. A sample was collected from the soil layer at 7.5 below ground surface and it met cleanup levels. Soil may be limited in extent. This information is intended to inform any future owners/operators of the environmental status of the property so they are aware of environmental and/or safety requirements. Beatrice Egbejimba
10/24/2003 Long Term Monitoring Established Long-Term Monitoring is one of the conditions for the NFRAP decision. A ground water monitoring plan in accordance with 18 AAC 75.345(h) should be developed that identifies the wells and frequency of sampling. The plan should be prepared and submitted to ADEC for review and approval. It should include a groundwater monitoring event in July 2004 to verify current water quality conditions and evaluate any trend in contaminant concentrations. If the monitoring indicates an increasing trend in contaminant levels, ADEC may require continued monitoring and assess the need for additional cleanup. However, a stable or decreasing trend may allow the monitoring frequency and locations to be reduced or discontinued. Beatrice Egbejimba
12/9/2003 Update or Other Action ADEC approved groundwater monitoring plan received November 34, 2003. The plan proposes to monitor MW-1 and MW-3 annually for gasoline-range organics (GRO), diesel-range organics (DRO), and total benzene, toluene, ethylbenzene, and xylenes (BTEX). Groundwater monitoring will take place annually in July for two consecutive years. If analytical results are below the Table C levels, the monitoring frequency will be reduced. Beatrice Egbejimba
1/20/2004 Update or Other Action ROD and NFRAP letter sent to property owner-Elaine Andersen's Hawaii address was returned to ADEC. Staff tried to contact Bob Shipley of UNOCAL for current address but he was not available. A message was left for Bob Shipley and the letter has been returned to the UNOCAL Portage file pending new contact information. Beatrice Egbejimba
2/10/2004 Update or Other Action Mail returned from Girdwood address with a new possible address from postmaster. Mail was resent to P.O.Box 1081, Naalehu, HI 96772-1081 based on new information. Beatrice Egbejimba
3/3/2004 Update or Other Action ADEC received phone call from Elaine Anderson regarding ROD. Property owner complained that she was not informed about the ROD and had not received a copy. She wanted no restrictions placed on the use of her groundwater. ADEC explained that the letter had been sent and returned twice. Property owner provided e-mail, home phone number and address. A copy of the ROD was faxed and e-mailed to the number and address provided. Beatrice Egbejimba
3/5/2004 Update or Other Action ADEC received phone call from land owner and consultant regarding ADEC’s NFRAP decision. In a follow-up e-mail land owner via consultant requested that ADEC specifically indicate that condition 5 does not in any way limit the use of groundwater from the Anderson's domestic well. Condition 5 requirement states that the transport of soil or groundwater from this site requires prior ADEC approval in accordance with 18 AAC 75.325(i). Land owner also requested copies of the ROD as they had not yet seen the document. ADEC sent a fax copy as well as an e-mail copy. Three previous attempts at sending document had failed. See previous entries for more information. Beatrice Egbejimba
9/29/2004 Meeting or Teleconference Held Contacted Scott Thursall requested July 2004 GW montioring report. David Allen
3/8/2005 Document, Report, or Work plan Review - other Received groundwater monitoring report. Analyticals indicate that most wells are non-detect. One well contained low levels of GRO which was below Table C cleanup levels. Eric Henry
10/27/2005 Document, Report, or Work plan Review - other Reviewed groundwater monitoring report, which was conducted in July 2005. The levels of GRO, DRO, and BTEX in monitor wells MW-1R and MW-3 did not exceed 18 AAC 75.345 Table C values. A letter will be constructed and submitted to responsible party requesting a meeting in order to evaluate groundwater monitoring frequency. Todd Blessing
4/11/2008 Exposure Tracking Model Ranking Initial ranking with ETM completed. Todd Blessing
5/1/2008 Document, Report, or Work plan Review - other June 24, 2007 groundwater monitoring event. Up to <0.01 mg/l GRO, 0.082 mg/l DRO, and <0.001 mg/l benzene in the groundwater. The levels of GRO, DRO, and BTEX in the two monitor wells sampled (MW-1R and MW-3R) did not exceed 18 AAC 75.345 Table C values. Groundwater was between 5.13 to 8.53 feet below ground surface. Robert Weimer
7/2/2008 Site Characterization Workplan Approved ADEC conditionally approves workplan to drill an angle boring near the building to assess the current contaminant concentrations in the area identified as having 0.0311 mg/kg benzene and 1590 mg/kg DRO at 7 feet below ground surface in a sand seam that ended at 7.5 feet below ground surface in a silty layer. The silty layer was sampled at 7.5 feet and that sample met site cleanup levels. The impacted layer is estimated to be 1 foot thick and 6 feet wide. Robert Weimer
8/12/2008 Meeting or Teleconference Held RP's consultant called and stated that they may not be able to do the angle boring proposed due to buried electrical line near foundation. They will look at other options to collect a confirmation soil sample from that area. Robert Weimer
9/12/2008 Site Characterization Workplan Approved ADEC conditionally approves revised workplan to drill an angle boring near the building to assess the current contaminant concentrations in the area identified as having 0.0311 mg/kg benzene and 1590 mg/kg DRO at 7 feet below ground surface in a sand seam that ended at 7.5 feet below ground surface in a silty layer. The silty layer was sampled at 7.5 feet and that sample met site cleanup levels. The impacted layer is estimated to be 1 foot thick and 6 feet wide. The condition in the approval is that the DRO results are reported without silica gel cleanup. Robert Weimer
11/21/2008 Cleanup Plan Approved Review and approve treatment of one drum of contaminated drill cuttings generated during the October 2008 confirmation sampling. Robert Weimer
12/11/2008 Document, Report, or Work plan Review - other April 14, 2008 groundwater monitoring event. Up to <0.05 mg/l GRO, <0.391 mg/l DRO, and <0.0005 mg/l benzene in the groundwater. The levels of GRO, DRO, and BTEX in the two monitor wells sampled (MW-1R and MW-3R) did not exceed 18 AAC 75.345 Table C values. Groundwater was between 4.35 to 8.09 feet below ground surface. Robert Weimer
2/25/2009 Meeting or Teleconference Held Meeting with Chevron and their consultants. ADEC is to review subsurface investigation report and request for cleanup complete status. Robert Weimer
3/16/2009 Document, Report, or Work plan Review - other June 4, 2008 groundwater monitoring event. Up to <0.05 mg/l GRO, <0.397 mg/l DRO, and <0.0005 mg/l benzene in the groundwater. The levels of GRO, DRO, and BTEX in the two monitor wells sampled (MW-1R and MW-3R) did not exceed 18 AAC 75.345 Table C values. Groundwater was between 4.42 to 8.04 feet below ground surface. Robert Weimer
3/17/2009 Document, Report, or Work plan Review - other August 7, 2008 groundwater monitoring event. Up to <0.05 mg/l GRO, <0.40 mg/l DRO, and <0.0005 mg/l benzene in the groundwater. The levels of GRO, DRO, and BTEX in the two monitor wells sampled (MW-1R and MW-3R) did not exceed 18 AAC 75.345 Table C values. Groundwater was between 5.72 to 8.35 feet below ground surface. Robert Weimer
3/17/2009 Document, Report, or Work plan Review - other October 29, 2008 groundwater monitoring event. Up to <0.05 mg/l GRO, <0.40 mg/l DRO, and <0.0005 mg/l benzene in the groundwater. The levels of GRO, DRO, and BTEX in the two monitor wells sampled (MW-1R and MW-3R) did not exceed 18 AAC 75.345 Table C values. Groundwater was between 4.09 to 7.81 feet below ground surface. Robert Weimer
3/31/2009 Document, Report, or Work plan Review - other ADEC approves suspending groundwater monitoring pending review of cleanup complete request. Robert Weimer
12/3/2009 Site Characterization Report Approved Review Subsurface Investigation Report and Cleanup Complete Request report. On October 22, 2008 four soil borings were advanced to 4 to 8.5 feet below ground surface. Up to <21.0 mg/kg DRO, <2.91 mg/kg GRO, and <0.0117 mg/kg benzene in the soil samples collected. All samples meet default cleanup levels. The report recommends this site for closure. Robert Weimer
12/18/2009 Meeting or Teleconference Held Left message with RP's consultant. The monitoring wells are approved for decommissioning, and request documentation of that prior to site closure. Robert Weimer
5/25/2010 Document, Report, or Work plan Review - other DEC approves workplan to decommission the remaining two monitoring wells at the site (MW-1R and MW-3R) in accordance with the DEC's February 2009 Monitoring Well Guidance. They are to provide a copy of the field notes when the work has been completed. Robert Weimer
6/11/2010 Document, Report, or Work plan Review - other DEC receives notification of the decommissioning of the remaining two monitoring wells at the site (MW-1R and MW-3R) in accordance with the DEC's February 2009 Monitoring Well Guidance. Robert Weimer
12/21/2010 Update or Other Action ETM updated to reflect recent soil and groundwater data. All soil and groundwater meet default cleanup levels. Robert Weimer
12/21/2010 Exposure Tracking Model Ranking A new updated ranking with ETM has been completed for source area 72986 Diesel Contaminated Soil. Robert Weimer
11/23/2011 Institutional Control Record Removed Cleanup Complete letter issued on 11/22/2011. Robert Weimer
11/23/2011 Cleanup Complete Determination Issued Robert Weimer
11/23/2011 Institutional Control Record Removed Institutional Controls have been removed. Robert Weimer
11/23/2011 Long Term Monitoring Complete Administrative action on 5/1/2013. Kristin Thompson
8/7/2015 Update or Other Action This file has been archived. Barcode 896956 Box 390 Susan Carberry
8/7/2015 Update or Other Action This file has been archived at Alaska Archives Barcode: 896956 Box 390 and 795760 Box 389 Susan Carberry

Contaminant Information

Name Level Description Media Comments
DRO < Method 2 Most Stringent Soil
DRO < Table C Groundwater
GRO < Method 2 Most Stringent Soil
GRO < Table C Groundwater
BTEX < Method 2 Most Stringent Soil
BTEX < Table C Groundwater

Control Type

Type Details
No ICs Required

Requirements

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

No associated sites were found.

Missing Location Data

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