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Division of Spill Prevention and Response Contaminated Sites

Project History: Technical Activity and Public Outreach

Updated: November 20, 2024

Table of Contents

1970 - 2008

View more information on the site history of the North Pole Refinery in DEC's Database of Contaminated Sites

1977
Refinery begins production using crude oil from the Trans-Alaska Pipeline.
1970s to early 1980s
Petroleum product leaks from above-ground storage tanks; consequently these tanks are taken out of service.
1980
MAPCO purchases the refinery.
1985
Sulfolane unit installed.
1986
DEC issues a Compliance Order by Consent, which outlines a cleanup and monitoring strategy for the petroleum contamination.
Mid to late 1980s
Monitoring well data indicates that groundwater on the refinery is contaminated with petroleum compounds, such as benzene, ethylbenzene, toluene, xylenes, (BTEX) trimethylbenzenes and naphthalene, above DEC’s regulatory maximum contaminant levels for drinking water. The drinking water used at the refinery is tested and found to be unaffected, as is the city water system. At this time, the refinery begins treatment and monitoring of the groundwater and performs further site characterization.
1989
The U.S. Environmental Protection Agency (EPA) issues two Resource Conservation and Recovery Act (RCRA) Administrative Orders to MAPCO. The orders outline a cleanup and monitoring strategy for the RCRA hazardous waste violations.
1998
MAPCO merges with The Williams Companies.
2004
The Williams Companies sells the facility to Flint Hills Resources.

2009

October to November

  • Sulfolane is discovered in wells north of the refinery property boundaries: Flint Hills (FHR) begins testing groundwater in monitoring wells outside of its property, near private homes with drinking water wells. Sulfolane concentrations in the monitoring wells are higher than expected, although below the 350 micrograms per liter cleanup level previously established for onsite wells.
  • Flint Hills, as the responsible party, notifies DEC with the results and with a plan to immediately supply alternate water and begin testing residential wells. Bottled water is provided to those impacted.
  • DEC asks the Alaska Department of Health and Social Services (DHSS) for assistance in reviewing the sulfolane cleanup level for its protectiveness of human health.

View more detailed information on the site history of the North Pole Refinery in DEC's Database of Contaminated Sites.

2009 Outreach

November 20
  • A comprehensive DEC website on the sulfolane investigation is established.
November 23
  • DEC holds its initial public meeting in North Pole. Representatives from DEC, Flint Hills Resources and DHSS participate.

2010

  • FHR continues to provide bottled water to those impacted.
  • Flint Hills completes a comprehensive search for drinking-water wells and sampling effort.
  • City of North Pole municipal wells are tested weekly from October 2009 through February 2010.
February
  • The federal Agency for Toxic Substances and Disease Registry (ATSDR) publishes a health consultation recommending a public health action level of 25 parts per billion of sulfolane in drinking water.
March
  • DEC forms a collaborative Technical Project Team (TPT) to provide comprehensive and coordinated oversight for the investigation. The team consists of government and industry representatives and multidisciplinary experts.
April
  • Flint Hills installs new wells for the City of North Pole public water system, even though sulfolane concentrations in the former City wells were consistently below 10 parts per billion.
  • Rigorous inspections of the refinery are conducted to identify any potential ongoing sources of sulfolane contamination.
  • DEC and FHR develop a site characterization work plan to investigate the extent contamination and evaluate exposure.
  • The TPT completes a garden sampling project involving several local gardeners to investigate if sulfolane accumulates in plant tissues.
September
  • FHR begins a pilot study of a granular activated charcoal (GAC) technology for removing sulfolane from groundwater.

2010 Outreach

January
February
April
May
  • Community open house is held.
August
October
  • DEC holds its second community open house to review the Technical Project Team’s current work and findings on the sulfolane investigation.

2011

  • The sulfolane plume is found to extend 3 miles downgradient from the refinery and approximately 2 miles wide at its widest area (off-site). Sulfolane is detected in private wells above and below permafrost.
January
  • New North Pole public drinking water system wells begin operation.
  • DHSS issues the final results of the North Pole garden sampling (PDF), recommending that North Pole gardeners in the plume area use an alternative water source to grow fruits and vegetables until more information is known.
February
  • Flint Hills submits a feasibility study to build home treatment systems to treat sulfolane using granulated activated carbon filters.
May
  • ATSDR develops action levels for sulfolane in drinking water, with the most protective level being for infants, at 20 parts per billion, in its Health Consultation – Sulfolane (PDF)
  • DEC issues guidelines for the groundwater analysis of sulfolane, creating specific procedures that all laboratories analyzing water for sulfolane must meet.
August
  • The groundwater monitoring network continues to be expanded on and off the refinery property for horizontal as well as vertical delineation of contamination.
  • FHR's point of entry water treatment systems receive certification from the Water Quality Association (PDF).
  • Available private well records and logs are reviewed to enhance the understanding and interpretation of the private well sampling data.
  • FHR identifies past spills and releases through a records review, which indicates that sulfolane releases into groundwater were mostly from subsurface wastewater containment systems.
  • FHRA inspects and tests the refinery sump systems, correcting weaknesses, encouraging plant-wide spill prevention and control, and initiating preventative maintenance programs.
  • Surface water samples collected from the refinery gravel pits and the Badger Slough do not contain sulfolane.
  • FHRA and its contractors continue work to provide an alternate water supply to the homes outside the City of North Pole limits with wells impacted by sulfolane: The residential and commercial locations have one of the following permanent solutions: an in-home water treatment system, a bulk water tank or long-term bottled water delivery services. Bulk tanks are provided to home for gardening water, if requested.

2011 Outreach

January
April
May
October

2012

January
May
  • FHRA submits a draft risk assessment, which includes calculations of different alternative cleanup levels based on different assumptions.
July
  • DEC sets a site-specific cleanup level for sulfolane of 14 parts per billion (as of 2014 this level has been appealed and is under review).
August
  • EPA announces completion of a Preliminary Assessment of the refinery.
  • FHRA submits Feasibility Studies that do not meet the established requirements.

2012 Outreach

January
April
May
  • A community open house is held to update the community.
September

2013

  • FHRA conducts an additional door-to-door survey of homes on City water in the affected area to ensure people are aware of the DHSS recommendation to use non-impacted water to water vegetable gardens.
Summer
  • FHRA conducts a permafrost mapping survey to better understand permafrost formations, improving understanding of groundwater movement and aiding in predicting plume behavior.
  • About 80 additional monitoring wells are installed and about 240 soil and water samples collected over the summer and fall.
  • UAF continues working with DEC conducting research on the degradation of sulfolane and transport of sulfolane through discontinuous permafrost.
  • Soil and surface water from gravel pits are sampled for sulfolane.
  • Soil is sampled from lawns and flower gardens watered with sulfolane-containing water.
November
  • DEC's Spill Prevention and Response Division gives conditional approval to FHRA’s Human Health Risk Assessment and establishes a cleanup level of 14 parts per billion (ppb) for sulfolane at the North Pole Refinery.
  • Gravel pit study results (PDF) show that the surface water in gravel pits does not contain sulfolane, and there's no danger in moving gravel to other areas.
December

2013 Outreach

February
June
  • The seventh newsletter (PDF) is published.
  • DEC letter and survey mailed to all property owners in affected area, living in- and out-of-state, expands communication with those affected.
  • DHSS issues a fact sheet Health Recommendations and Next Steps (PDF), summarizing recommendations to date.
  • State Agency open house, at North Pole City Hall, with DEC staff and team, and DHSS representatives.
August through September
  • Responses sent to property owners who responded to the June survey with questions or issues.
December

2014

January
March
  • The State files a lawsuit against the current and former owners of the North Pole Refinery. DEC continues oversight of the site investigation and cleanup.
  • DEC issues a garden soil study report from testing indicating that using sulfolane-contaminated water on gardens does not leave residual sulfolane in the soil.
April
  • DEC's Commissioner “vacates” the Spill Prevention and Response Division’s 14 parts per billion cleanup level decision. This decision meant no cleanup level number was in effect. He also gave instructions for the Division’s further consideration and explanation in a setting a new cleanup level.
June
  • FHRA submits a supplement to its Human Health Risk Assessment, proposing a cleanup level of 362 ppb.
Summer
  • FHRA expands the groundwater extraction system at the refinery as part of their proposed interim remedial actions.
  • UAF continues working with DEC conducting research on the degradation of sulfolane and transport of sulfolane through discontinuous permafrost.
July
  • DEC develops an interim best management practices plan to assist with the management of dewatering activities near or within the sulfolane plume. See June 2014 newsletter (PDF) for summary.
  • The sulfolane plume's approximate size to date is 3.5 miles downgradient (northwest) from the refinery, 2 miles wide and over 300 feet deep.
September 16 to 17
  • At SPAR Division’s request, an independent, expert peer review of the available reference doses for sulfolane is conducted in Fairbanks by the non-profit organization Toxicology Excellence for Risk Assessment (TERA). This is part of the division’s detailed analysis ordered by the Commissioner. A reference doses is one of a number of factors used in calculating a cleanup level.
October
December
  • TERA report is released, concluding that none of the reference doses (or toxicity values) aligned perfectly with the recommendations of the expert panel. Although the report concluded that the value proposed by FHRA most closely aligns with the panel’s conclusions, the experts identified a number of uncertainties about the toxicity of sulfolane, including lack of reliable, long-term studies on the health effects of long-term exposure to sulfolane. (See the report).
  • DEC meets with the National Toxicology Program and learns they plan to begin long-term studies to address the remaining uncertainties about the health effects of exposure to sulfolane.

2014 Outreach

January
April
June
September
October

2015

May
  • The National Toxicology Program (NTP) initiates a 2-year study to address important data gaps regarding sulfolane exposure, including the effects of long-term exposure to this chemical. The NTP studies are expected to provide a clearer picture of the risks associated with sulfolane exposure. (See the NTP fact sheet for more details (PDF) (Fact sheet revised Nov. 2018)
June
June/July

2015 Outreach

June
August
  • DEC issues the tenth community newsletter (PDF).
  • DEC holds a public open house at North Pole Branch Library, with representatives from DEC, DHSS, and Flint Hills.

2016

August
  • The 2014 Onsite Cleanup Plan is modified to cease operation of the western groundwater extraction and treatment system, due to low levels of influent contamination. Operation of the original (eastern) onsite treatment system and groundwater monitoring continues.
September

2017

February
  • Flint Hills Resources Alaska and the State of Alaska announce on February 7th, 2017, that they will be working with the City of North Pole to significantly expand their piped public water system to provide sulfolane-free drinking water to residents impacted by the sulfolane groundwater plume. 
  • A Revised 2017 Onsite Cleanup Plan is released.
July
  • Under the 2017 Revised Onsite Cleanup Plan, operation of the onsite groundwater recovery and treatment system is replaced by intensive groundwater monitoring. Contingencies are in place to resume active treatment if the plan goals are not met. (See fact sheet on the Revised Onsite Cleanup Plan (PDF).
October-December
  • Stantec, an international engineering firm with a local office in Fairbanks, completes design of the piped water system expansion. The project is put out for proposals, and the City of North Pole selects Exclusive Paving to construct the main water lines.

2017 Outreach

February
December

2018

February
  • Surveying and land clearing begin in Zones 1 and 2 to prepare for the main water line installation.
March
  • Pipe installation begins in Zones 1 and 2 along the City’s northern boundary. Construction of the main water lines is scheduled to occur in two phases in 2018 and 2019.
Summer-Fall
  • DEC takes advantage of an existing monitoring program and samples some water wells in the North Pole area for PFAS. DEC has been aware that fire-fighting foams containing PFAS were historically used on the former North Pole Refinery property. Test wells for this sampling are selected to look for PFAS across a wide range of groundwater conditions and to evaluate whether the POE systems provided to some residents for removal of sulfolane from their well water also effectively remove PFAS. DEC also collects samples from Kimberly Lake, located to the northwest of the former refinery, and from three locations in Badger Slough. Sample results show a PFAS plume emanating from the former refinery.
August
  • DEC sets action levels for six PFAS compounds, including PFOS and PFOA. The action level is 70 parts per trillion (ppt) – for the sum of PFOS, PFOA, PFNA, PFHxS, and PFHpA.
Fall
  • City of North Pole contractor completes installation of water mains in Zones 1 and 2.
  • The Alaska Department of Fish and Game (ADF&G) collect three fish from Kimberly Lake for PFAS analysis. PFAS are detected at levels of concern, and the Alaska Department of Health and Social Services issues interim advice to not consume surface water or fish from Kimberly Lake.

2018 Outreach

January
  • Exclusive Paving develops a project Facebook page.
  • The City of North Pole creates a project website.
February
  • DEC updates website with new Frequently Asked Questions (FAQs) (PDF).
  • On February 24th 2018, a Community Open House is held at the North Pole Plaza to provide updated information and an opportunity to discuss the project with representatives of the City of North Pole, FHRA, and the State of Alaska, as well as Stantec, Inc. - the water expansion design consultant - and Exclusive Paving - the contractor to construct the main water lines. Community members view large-size maps. Small maps are available as handouts, along with fact sheets explaining the most current information on the project, including: 2018 Update on the North Pole Public Water System Expansion Project (PDF).
November
  • DEC issues a Contaminated Groundwater Advisory to all property owners within the North Pole piped water expansion area where many private water wells contain sulfolane, and/or per- and poly-fluoroalkyl substances (PFAS). The advisory assists residents in avoiding unintentional contact with, or spreading of, the chemicals.
December

2019

April
  • DEC publishes a revised Technical Memorandum on Action Levels for PFAS that supersedes the 2018 action levels memorandum and aligns the action levels with EPA’s Lifetime Health Advisory (LHA) levels for PFOS and PFOA. Action levels serve as thresholds for determining when responsible parties need to provide water treatment or alternative water sources for impacted water supplies.
October
  • A trial is held in Fairbanks Superior Court for litigation between the State of Alaska, Flint Hills Resources Alaska and Williams Alaska Petroleum Inc.
Fall
  • City of North Pole contractor completes installation of water mains in Zones 3 and 4. Most of the Zone 1 and 2 properties were connected to the city’s piped water system by the end of 2019.
December

2019 Outreach

February 26
  • DEC gives notice to the sulfolane email group that PFAS are present in Kimberly Lake near the former refinery and updates the main page (Project Home) of this website with Kimberly Lake PFAS information. Links are provided to a fact sheet on PFAS by the Alaska Department of Health and Social Services.
  • The City of North Pole creates a project website.
March 27
  • DEC posts to the website an update to the October 2018 fact sheet on the department’s PFAS investigation in the North Pole area. The update provides results of the two phases of 2018 water testing. The second round of sampling included additional water wells as well as surface water.
December 4

2020

January 3
  • The Alaska Department of Law announces the court decision in the trial to settle the litigation between the State of Alaska, Flint Hills Resources Alaska and Williams Alaska Petroleum Inc. The Fairbanks superior court decision holds Williams Alaska Petroleum, Inc. liable for releasing large quantities of sulfolane and PFAS into the groundwater under the North Pole Refinery, polluting hundreds of residents’ drinking water wells.
March 23
  • Final Judgement issued by the Fairbanks Superior Court, with requirements for sulfolane monitoring and reporting, addressing PFAS in soil and groundwater at the former refinery, and complying with DEC’s site cleanup rules.
April
  • Alaska Department of Fish and Game issues an Emergency Order 3-R-U-02-20 to close Kimberly Lake to sport fishing due to PFAS found in fish in Kimberly Lake.
July 13
  • Williams Alaska Petroleum Inc. appeals the Fairbanks Superior Court ruling and judgement.
August 19
  • Williams submits a 2020 Annual Offsite Sulfolane Plume Monitoring Plan, outlining the 2020 annual monitoring of sulfolane in groundwater located downgradient of the former refinery.
September - December
  • Williams prepares an Onsite Groundwater and Surface Water PFAS Characterization Workplan, outlining the 2020 PFAS characterization activities planned for groundwater and surface water on the former refinery. A work plan addendum was submitted in December 2020.
December
  • By the end of 2020, all eligible property owners were offered connection to the service and able to phase out the use of contaminated groundwater wells. Most property owners were eligible to connect at no cost, depending upon the land’s location and improvement status. The expanded system provides permanent protection from contamination in drinking water.

2020 Outreach

September-October

2021

August
  • Williams submits a 2021 Site Characterization Report that presents the results of focused characterization activities on the former refinery property to assess the horizontal and vertical extent of per-and polyfluoroalkyl substances (PFAS) in groundwater and surface water and to identify potential areas for future evaluation.

2022

August
  • Williams prepares submits a 2022 Site Characterization Work Plan Addendum for additional PFAS characterization activities on the former refinery property. The final addendum was approved by DEC in August.

2023

January 24
  • Flint Hills submits a 2022 Annual Onsite Groundwater Monitoring and Five-Year Periodic Review, of onsite (on the former refinery property) monitoring, summarizing onsite field activities completed during the first and third quarters of 2022 as well as a review of activities over the past five years.

2023 Outreach

May
  • DEC updates the website with information on completion of the City of North Pole’s expanded public water system. FAQs and other key pages are updated. Annual monitoring reports, along with maps of the extent of contamination are added.
  • A May 2023 fact sheet is sent to its electronic mailing list to update North Pole residents and others interested in the state’s response to groundwater contamination at and north of the former North Pole Refinery. Recent project milestones are discussed. Copies are provided to the City of North Pole offices.

2024

January
  • Williams submits a 2022 Annual Monitoring and Five-Year (2017-2021) Offsite Sulfolane Plume Monitoring Report, of offsite (off the former refinery property) monitoring, summarizing offsite field activities completed during 2022 as well as a review of activities over the past five years (2017-2021).
July
  • DEC approves Williams’ work plan to evaluate properties near the former refinery for possible alternative water supplies. Although eligible and willing property owners were connected to the City of North Pole’s expanded piped water system by 2020, iIt is possible that other properties may now be eligible to receive water.
October
  • DEC approves Williams’ evaluation of potential remedies to address PFAS remaining in soil and groundwater on the former refinery property and a work plan for interim remedial actions to address some of the contamination. Williams also submits work plans for long-term PFAS groundwater monitoring, additional soil and groundwater characterization, and fish sampling on the former refinery.

2024 Outreach

November

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Location:  410 Willoughby Avenue, Juneau