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Updated: Mar. 23, 2017

Site Investigation and Remediation

 

Soil and groundwater at the North Pole Refinery have been affected by petroleum spills that occurred throughout the duration of refinery operation, beginning in the late 1970s. A large portion of the refinery’s land (approximately 24 acres) still contains fuel product trapped in the soil and groundwater. Some of the fuel components have also dissolved into the groundwater, creating a large area, or “plume,” of groundwater contamination. In addition to typical fuel components, the chemical sulfolane was identified in groundwater under the refinery in 2001. Sulfolane is used in the refining process.

(See pdf Introduction to Groundwater fact sheet.)

 

In 2009, groundwater containing dissolved sulfolane was found in wells beyond the refinery property. The groundwater sulfolane plume is approximately 2 miles wide, 3.5 miles long and over 300 feet deep and has impacted approximately 350 drinking water wells in the area. No other chemicals have migrated beyond the refinery property.

 

While Alaska regulations contain cleanup levels for fuel components, sulfolane is a less common chemical, and there is currently no cleanup level established for it in Alaska. The August 2015 newsletter describes the sulfolane cleanup level situation. pdf August 2015 newsletter (1.5MB)

 

This page includes information on:

 

 

Site Characterization


Under Alaska regulations, the extent of contamination is to be characterized before proceeding with cleanup at a contaminated site. The site characterization requirements are laid out in regulation (18 AAC 75.335) and generally include investigation activities to determine the types of contaminants present, the source areas, possible risk to people and the environment, the possible need for interim cleanup actions, and the extent of the contamination, both horizontally and vertically.

 

Site characterization includes:

    • Preparing a detailed work plan of the intended activities for DEC approval,
    • Performing the investigation,
    • Reporting the results.

 

The site characterization reports include an evaluation of potential cleanup activities that may be appropriate at the site. More information on the State of Alaska cleanup process is available at the links below:

 

On the North Pole Refinery, multiple site investigations have been performed since the 1980s. Past site characterization efforts have included installing groundwater monitoring wells as well as collecting soil and groundwater samples to determine the contamination extent and track plume movement. New monitoring wells were installed as needed to monitor progress of cleanup efforts.

 

The 2009 discovery of sulfolane beyond the refinery property initiated a new round of very detailed characterization efforts. Investigations were performed onsite to evaluate the source of the sulfolane contamination. Offsite investigations assessed the size and boundaries of the sulfolane contamination. Contamination was found to be distributed over a large area across the refinery and to the north-northwest of it, both above and below areas of permafrost.

 

As a result of the complicated contaminant distribution, more specialized characterization tools have also been used at the North Pole Refinery site. A geophysical investigation was used to estimate the extent of the discontinuous permafrost, and a groundwater model was developed to simulate groundwater flow and contaminant transport.

 

Current monitoring efforts include periodic sampling of selected onsite and offsite groundwater monitoring wells to evaluate performance of onsite treatment and track plume migration.

 

The most recent and complete characterization reports are listed below:

 

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Interim Cleanup - Onsite

 

Actions to clean up the spilled petroleum at the refinery have been ongoing since the 1980s.  Recovery wells have been used to remove accumulations of fuel from the water table. Contaminated groundwater has been pumped out of the ground and processed through a treatment system located at the refinery. The treated water is returned to onsite gravel pits and ultimately flows back into the groundwater. The remediation systems have been periodically updated over the years to improve the treatment effectiveness. In 2011, the systems were upgraded to add granulated activated carbon (GAC) filtration specifically to remove sulfolane from the water.

 

A series of Interim Remedial Action Plans documented the interim cleanup actions. The most recent is listed below:

 

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2014 Onsite cleanup Plan


In October 2014, DEC approved an Onsite Cleanup Plan to address contamination on the North Pole Refinery property. Under the Plan, the existing groundwater extraction and treatment system was expanded in an effort to capture all sulfolane above a performance standard of 15 parts per billion, before it migrates off the refinery. Petroleum accumulations on the groundwater table continue to be pumped out and treated. The Plan also includes protection of workers through engineering and administrative controls and removal of some contaminated soil. Soil excavation and treatment took place during the summer 2015. Referenced documents are listed below:

 

Under the terms of the Onsite Cleanup Plan, Flint Hills performs groundwater sampling quarterly to monitor treatment system performance. Details regarding operation, maintenance, and monitoring of the groundwater extraction and treatment system and fuel recovery operations are provided in the document listed below:

 

Also under the terms of the Plan, Flint Hills performs long-term groundwater sampling to evaluate changes in the groundwater plume. Groundwater samples are collected quarterly, semi-annually, and annually from selected locations. Details regarding the long-term monitoring are provided in the document listed below.

 

The performance and long-term monitoring results are compiled into two semi-annual reports every year. Reports are available below.

 

Sulfolane that has migrated beyond the refinery boundary is not addressed in the Onsite Cleanup Plan.

 

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Offsite Sulfolane Plume, Monitoring and Other Issues


Much has been done so far to characterize the off-site plume (see Site Characterization above). To date there is no cleanup plan for sulfolane beyond the refinery property. People living in the area impacted by sulfolane contamination are being provided with alternative drinking water (see below).


Under the Onsite Cleanup Plan, the groundwater extraction and treatment system was expanded in an effort to capture all sulfolane above the performance standard of 15 parts per billion, before it migrates off the refinery. The resulting decrease in sulfolane migrating from the refinery has brought about decreasing sulfolane concentrations in groundwater just north of the refinery.


Although sulfolane concentrations near the refinery are decreasing, the offsite sulfolane plume continues to migrate towards the north-northwest. The plume is expanding into previously-uncontaminated areas. The rate of migration of the sulfolane plume is fairly slow and is being monitored by sampling of groundwater monitoring wells and private drinking water wells. Under DEC oversight, Flint Hills collects groundwater samples from selected monitoring and private wells at intervals ranging from quarterly to annually. The monitoring results are compiled into two semi-annual reports every year. Reports are available below.

 

Excavations within the Plume

Releases of sulfolane at the North Pole Refinery (NPR) have resulted in a contaminated groundwater plume that extends throughout much of the City of North Pole, Alaska, and beyond the city boundaries. The potential exists for development as well as utility maintenance projects within North Pole and beyond to be severely impacted by the logistics for managing excavations that require dewatering within the sulfolane plume boundary. A plan for managing excavation dewatering fluids in compliance with applicable regulations is necessary to reduce impacts on projects in North Pole and surrounding impacted areas.

 

An Interim Excavation Dewatering Management Plan finalized in 2014 provides guidance for managing excavation water generated during construction dewatering activities in the vicinity of the North Pole sulfolane groundwater plume. The overarching management goals are to minimize the volume of contaminated water to be discharged and to manage the discharge so that it does not cause sulfolane contamination in areas that were previously uncontaminated.

 

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Alternative Water Solutions


People living in the area impacted by sulfolane groundwater contamination (to the north-northwest of the refinery) are being provided with alternative drinking water supplies to protect them from exposure to sulfolane in the groundwater. Flint Hills is providing residents with either sulfolane-free drinking water or point-of-entry treatment systems for their well water. Flint Hills is obligated to continue to provide alternative water for anyone whose water is impacted by sulfolane at any detected concentration until a cleanup level is set. The alternative water solutions program and recent monitoring results are described in the documents listed below.

 

See also the page on Drinking Water Private Wells 

 

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Site Investigation and Remediation:
Project Documents and Reports

 

Categories of documents

    Site Characterization Documents
    Posted
    Download

    2013 DRAFT Onsite Site Characterization Addendum Report, December 20, 2013, Arcadis, submitted to DEC by Flint Hills Resources Alaska, LLC.

     

    This document presents site characterization data collected in 2013 and the results of technical analyses based on these data. The technical analyses and discussions in this Onsite Addendum are informed by the full data set collected over the total site history and by historical findings.

     

    For copies of Figures and Tables or other help with this report, please contact DEC.

     

    6/22/16

    2013 DRAFT Offsite Site Characterization Addendum Report, December 20, 2013, Arcadis, submitted to DEC by Flint Hills Resources Alaska, LLC.

     

    This Offsite Addendum outlines results from field activities conducted in 2013. It also presents additional interpretations and conclusions based on ongoing private and monitoring well sampling and a review of the full data set for the site.

     

    For copies of Figures and Tables or other help with this report, please contact DEC.

     

     

    6/22/16

    2013 Onsite Site Characterization Work Plan, submitted to DEC by Flint Hills Resources Alaska, LLC, February 2013, Arcadis

    This work plan addresses recommendations presented in previous Site Characterization Reports and DEC's requests for additional site assessment on the refinery property.

     

    5/10/13

    2013 Offsite Site Characterization Work Plan, submitted to DEC by Flint Hills Resources Alaska, LLC, March 2013, Arcadis

    This work plan addresses recommendations presented in previous Site Characterization Reports and DEC's requests for additional site assessment. "Offsite" is the area located outside the refinery's property boundary in the downgradient north-northwest direction, based on the approximate extent of the dissolved phase sulfolane plume.

     

    For copies of Appendix items or other help with this report, please contact DEC.

     

    5/10/13

    Site Characterization Report - 2012 Addendum, submitted to DEC by Flint Hills Resources Alaska, LLC, Jan. 25, 2013, Arcadis

    Describes additional site characterization activities that ARCADIS and Shannon and Wilson, Inc. conducted during the second and third quarters of 2012. This is an addendum to the"Revised Site Characterization Report, March 2012, Barr Engineering" found below.

     

    For copies of Appendix items or other help with this report, please contact DEC.

     

    5/10/13

    Site Characterization Report, through 2011 - FINAL, submitted to DEC by Flint Hills Resources Alaska, LLC, December 2012, Barr Engineering

    Description of site characterization work completed through 2011 by Flint Hills Resources Alaska, LLC.

     

     

    8/11/14

    December 2009 Monthly Groundwater Remediation Status Report, from Flint Hills Resources to DEC. Includes historical benzene sampling from 1987 and sulfolane concentrations from 2006.  References two maps of the current groundwater concentrations from shallow (water-table) monitoring wells.

     

    1987-
    2006
    pdf Fig2-3M

    DEC's approval letter of 2002 Corrective Action Plan, Jan. 24, 2006, setting sulfolane cleanup level.

     

    1/24/06

    pdf icon 96K

    June 2002 Site Characterization and Corrective Action Plan, submitted to DEC for Williams Alaska Petroleum, Inc. (formerly MAPCO Alaska Petroleum, Inc.). and approved by DEC in January 2006 after Flint Hills Resources Alaska, LLC. acquired the refinery.

     

    June 2002

    pdf icon 3.3MB

    Contaminant Characterization Study, for Williams Alaska Petroleum, Inc., by Shannon and Wilson, 2001. Identified sulfolane as a contaminant; has monitoring results.

     

    2001
    pdf icon2MB
    Interim Cleanup Documents
    Posted
    Download

    Interim Remedial Action Plan Addendum, July 31, 2013 - Arcadis, submitted to DEC by Flint Hills Resources Alaska, LLC

     

    This plan Addendum proposes additional interim remedial actions to address light nonaqueous phase liquid (LNAPL) and groundwater impacts at the North Pole Refinery. This Addendum focuses on constituents of concern identified in the 2012 Revised Draft Final Human Health Risk Assessment and data collected during site characterization activities.

     

    6/22/16

    DEC's approval letter of 2002 Corrective Action Plan, Jan. 24, 2006, setting sulfolane cleanup level.

     

    1/24/06

    pdf icon 96K

    June 2002 Site Characterization and Corrective Action Plan, submitted to DEC for Williams Alaska Petroleum, Inc. (formerly MAPCO Alaska Petroleum, Inc.). and approved by DEC in January 2006 after Flint Hills Resources Alaska, LLC. acquired the refinery.

     

     

    June 2002

    pdf icon 3.3MB

    Onsite Cleanup Plan Documents, 2014 and later
    Posted
    Download

    2015 Operation, Monitoring, and Maintenance (OMM) Plan, Groundwater Remediation System, December 2015, Barr Engineering

     

    2015 Long-Term Groundwater Monitoring Plan, 2015 Update, December 14, 2015, Arcadis

     

     

    6/22/16

    pdf 3.4MB OMM Plan

     

     

    pdf 6.9MB Long-term Groundwater Monitoring Plan

     

    2015 Onsite Excavation Report, North Pole Terminal, North Pole, Alaska, November 30. 2015, Arcadis

     

    This report summarizes excavation activities completed during 2015 within Lagoon B,
    the Southwest Former Wash Area, and the Fire Training Area. The scope of the soil
    excavation work is defined in Section 5.3 of the Final Onsite Cleanup Plan (Arcadis 2014).

     

    6/22/16

    pdf11.5MB

    Final Onsite Cleanup Plan, North Pole Refinery, October 2014, Arcadis

    Final Long-Term Monitoring Plan, October 2014, Arcadis

     

    Operations, Maintenance, and Monitoring Plan, Groundwater Remediation System, October 2014, Barr Engineering

     

    Alternative Water Solutions Program - Management Plan, October 2014, Barr Engineering. (Large file size prevents us from posting Figures and/or Appendices; to see them, please contact DEC)

     

    10/20/14

    pdf Cleanup Plan 259K

     

    pdf Long-Term Mon. Plan 5.7M

     

    pdf OM&M Plan 9.1M

     

    pdf AWS Mgmt Plan 1.4M, minus Figures and Appendices

    Ongoing Monitoring
    Posted
    Download

    2016 Groundwater Monitoring Reports - submitted to DEC by Flint Hills Resources Alaska, LLC, Arcadis

    Onsite (on refinery property) monitoring):

    • First Semiannual 2016 Onsite Groundwater Monitoring Report, North Pole Terminal, July 2016
    • Second Semiannual 2016 Onsite Groundwater Monitoring Report, North Pole Terminal, January 2017

    .

    Offsite monitoring (of plume beyond the refinery):

    • First Semiannual 2016 Offsite Groundwater Monitoring Report, North Pole Terminal, July 2016
    • Second Semiannual 2016 Offsite Groundwater Monitoring Report, North Pole Terminal, January 2017.

     

    For copies of Appendix items or other help with this report, please contact DEC.

     

    3/23/17

     

     

    2015 Groundwater Monitoring Reports - submitted to DEC by Flint Hills Resources Alaska, LLC, Arcadis

    Onsite (on refinery property) monitoring:

    • First Semiannual 2015 Onsite Groundwater Monitoring Report, North Pole Terminal, July 2015
    • Second Semiannual 2015 Onsite Groundwater Monitoring Report, North Pole Terminal, January 2016

    .

    Offsite monitoring (of plume beyond the refinery):

    • First Semiannual 2015 Offsite Groundwater Monitoring Report, North Pole Terminal, July 2015
    • Second Semiannual 2015 Offsite Groundwater Monitoring Report, North Pole Terminal, January 2016.

     

    For copies of Appendix items or other help with this report, please contact DEC.

     

    6/22/16

     

     

    Additional Offsite Plume Documents
    Posted
    Download

    Final Interim Management Plan for Excavation Dewatering in the North Pole Sulfolane Plume, July 2014, ERM

    Provides guidance for managing excavation water generated during construction dewatering activities in the vicinity of the North Pole sulfolane groundwater plume.

     

    7/25/14

    pdf 6.8MB

    Report: Garden Soil Sampling, March 2014, ERM

    Results of soil samples from lawns and flower gardens in the North Pole area watered with sulfolane-laden water. No sulfolane was detected, indicating that the use of sulfolane-contaminated water at these locations did not leave residual sulfolane in the soil.

    6/5/14

    pdf Report, Tables 378K

     

    pdf Report with all Attachments 4MB

    Report: North Pole Gravel Pond and Slough Sampling, November 2013, ERM

    Results of sulfolane in surface water and sediment from several water bodies located within the sulfolane-affected area in North Pole. No sulfolane was detected above the reporting limit in gravel or surface water.

    6/6/14

    pdf Report, Maps, Tables 666K

     

    pdf Attachments A&B 6.3MB

     

    pdf Attachments C&D 3MB

    Third-party review of lab analysis of North Pole city water: "Assessment of Sulfolane Split-Sample Data Associated with the Flint Hills Resources Fuel Refinery in Fairbanks, Alaska," Dec. 9, 2009, Environmental Standards Inc.

     

    12/9/09
    pdf icon154K
    Reference Materials
    Report on groundwater flow in the Fort Wainwright area: "Estimate of Aquifer Properties by Numerically Simulating Ground-Water/Surface-Water interactions, Fort Wainwright, Alaska," by Allan S. Nakanishi and Michael R. Lilly for the U.S. Geological Survey, 1998.
    This study used a model to mimic the flow of water between the aquifer and the Chena River at Fort Wainwright. The USGS collects groundwater and surface-water data to understand the movement of water through the ground in the area. Data was collected monthly and sometimes more frequently to document short-term changes in groundwater caused by rapid changes in the Chena and Tanana Rivers. This document is in part used to guide DEC's conclusions about how groundwater moves in the area of North Pole.
    1998
    pdf icon 5.3MB

    Groundwater levels in an Alluvial Plain Between the Tanana and Chena Rivers
    Latest USGS report describing the regional groundwater flow in the Fairbanks North Star Borough.

     

     

    1996
    pdf icon 4MB
    Alternative Water Solutions
    Posted
    Download
    Alternative Water Solutions Program 2015 Annual Report, North Pole, Alaska - February 2016 - Barr Engineering Co.
    6/22/16
    pdf icon 4MB
    Alternative Water Solutions Program 2014 Annual Report, North Pole, Alaska - February 2015, - Barr Engineering Co.
    6/22/16
    pdf icon 4MB

     

    Alternative Water Solutions Program - Management Plan, October 2014, Barr Engineering. (Large file size prevents us from posting Figures and/or Appendices; to see them, please contact DEC)

     

    10/20/14

    pdf AWS Mgmt Plan 1.4M, minus Figures and Appendices