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Division of Spill Prevention and Response Contaminated Sites

North Pole Refinery

Site Location

DEC Contaminated Sites contact: Jim Fish, 907-451-2117  

  • Click on photos or maps for larger versions.
  • Contacts updated: 11/7/2024
  • Summary updated: 11/7/2024

Site Narrative

Current Status

Estimated boundary of sulfolane groundwater plume, showing municipal water lines

Map of North Pole Municipal Water Supply Lines and Sulfolane Plume (2017-2023) See the most recent maps on the Maps page

The former North Pole Refinery is currently being operated as the Marathon Terminal. Contamination from historical oil refining activities at the former refinery, located about 15 miles southeast of Fairbanks, has affected groundwater used as a source of drinking water in the North Pole area. Chemicals that have migrated beyond the former refinery property include sulfolane, a solvent used in the refining process, and per- and polyfluoroalkyl substances (PFAS), chemicals used in fire-fighting foams on the former refinery

As of summer 2024, a number of new and ongoing response activities address contamination remaining at the former North Pole Refinery and in the groundwater in the greater North Pole area.

Alternative Water Supply (AWS): In July 2024, DEC approved former refinery owner Williams Petroleum Alaska (Williams’) work plan to evaluate properties near the former refinery for possible alternative water supplies (AWS). Owners of properties that are not connected to municipal water are being contacted by Williams or their consultants. Properties with sulfolane in their well water may be eligible for connection to municipal water or alternative water. Although eligible and willing property owners were connected to the City of North Pole’s expanded piped water system by 2020, it is possible that other properties may now be eligible to receive water. The approved work plan and a map of the sulfolane plume may be found at the links below.

Interim Response to per- and polyfluoroalkyl substances (PFAS) on the former refinery: In July 2024, DEC approved Williams’ evaluation of potential remedies to address PFAS remaining in soil and groundwater on the former refinery property. Sampling performed in 2022 showed PFAS above DEC’s soil cleanup level on the refinery and PFAS in groundwater above DEC’s action level migrating off the former refinery property. In August 2024, DEC also received a work plan for interim remedial actions to address the contamination. The work plan was finalized in early October 2024 and promptly approved by DEC. The interim remedy is to be initiated in October 2024. The approved remedial evaluation, interim remedy work plan, recent sampling report, and map of recent groundwater results may be found at the links below.

In summer 2024, Williams also submitted work plans for long-term PFAS groundwater monitoring, additional soil and groundwater characterization, and fish sampling on the former refinery. The approved work plans may be found at the links below.

Offsite PFAS: In 2023 and early 2024, Williams sampled some offsite monitoring wells, a few private wells, and surface water in the first offsite PFAS sample event since DEC’s 2018 sampling. PFAS were found in groundwater above the DEC action level in some monitoring wells north of the former refinery. PFAS were also detected in the area’s lakes and ponds at concentrations below the DEC action level, and Badger (Chena) Slough samples contained low-level parts per trillion PFAS. The DEC action levels apply to groundwater and surface water used as drinking water. See below for a map of the 2023 offsite sample results; the report will be posted to the website when it is finalized.

Ongoing Groundwater Monitoring: Annual long-term groundwater monitoring continues both on and off the former refinery property under DEC oversight.

  • In summer 2024, Williams also submitted a work plan for 5 years of long-term sulfolane groundwater monitoring off the former refinery. Work plans will be posted to the website when finalized.
  • Onsite Sulfolane and Petroleum: Groundwater monitoring through 2023 has shown no indications of contamination migrating off the former refinery property above allowable limits. In samples from wells near the property boundary, petroleum (benzene, diesel-range organics, and gasoline-range organics) concentrations are below Alaska cleanup levels, and sulfolane concentrations are below the allowable limit. The 2023 onsite monitoring report and maps of most recent monitoring results may be found at the links below.

Municipal Water: The City of North Pole now provides a permanent source of sulfolane-free water to residents, landowners and businesses in the areas where groundwater has been contaminated by sulfolane. If you have questions, please contact the city’s website.

At A Glance fact sheet: A November 2024 fact sheet is available 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.

Description

Contamination from historical oil refining activities at the former North Pole Refinery (now Marathon Terminal), located about 15 miles east of Fairbanks, has affected groundwater used as a source of drinking water in the North Pole area.

The refinery operated from the late 1970s until it shut down in 2014. In 2009, the industrial solvent sulfolane, which was used in the refining process, was detected in drinking water wells off the former refinery property. Follow-on sampling showed sulfolane impacted approximately 350 drinking water wells. In 2018, PFAS used in fire-fighting foams on the former refinery were detected in groundwater off the property. The former refinery's land still contains fuel product trapped in the soil and groundwater.

The sulfolane groundwater plume is approximately 2 miles wide, 3.5 miles long, and over 300 feet deep, and it continues to migrate gradually northward. The PFAS plume appears to have a similar footprint, although the boundaries of the plume have not been fully evaluated.

Public Health and Environmental Concerns

Contamination summary: Soil and groundwater on the former refinery property are contaminated with sulfolane, PFAS and petroleum. Sulfolane and PFAS in contaminated groundwater have migrated off the refinery property.

Sulfolane is an industrial solvent used primarily in natural gas and petroleum refining. Most of what we know about how sulfolane might affect human health comes from studies in which laboratory animals were exposed to sulfolane for periods of time. The National Toxicology Program is currently studying the long-term effects of exposure to sulfolane in water on rodents. For more information on the toxicity of sulfolane and the National Toxicology Program studies, see the following:

Per- and polyfluoroalkyl substances (PFAS) are a large and complex class of human-made compounds which have a wide-range of toxicities. They are found in some firefighting foams and many consumer products.

The links below provide recent information regarding sulfolane and PFAS contamination off the former refinery property.


Drinking Water: The public in the affected area was provided access to alternative water solutions and recently has had the opportunity to connect to the North Pole municipal water system. Starting in 2009, alternative, sulfolane-free water or water treatment systems for sulfolane removal were provided to all properties with any detection of sulfolane in the water. In addition to providing protection from sulfolane, the water treatment systems were shown in 2018 to also remove PFAS from well water. In February 2017, the State of Alaska, then-owner Flint Hills Resources Alaska (FHRA), and the City of North Pole reached a settlement agreement to expand the City’s municipal water system to all improved properties located within the sulfolane plume or in its anticipated migration path. By the end of 2020, all eligible property owners were offered connection to the service and were 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. In 2024, Williams began evaluating properties near the former refinery that are not connected to municipal water for possible alternative water supplies. For information about municipal water system connections and use of well water within the affected area, see the following:

Gardening: In 2010, produce from North Pole gardens that used sulfolane-impacted well water for watering were sampled. The results were based on the testing of 23 types of plants from seven North Pole gardens. Results affirmed that some edible garden plants retain sulfolane from contaminated well water. Sulfolane levels in produce varied depending on the type of plant and part of the plant tested.

In 2018, DEC evaluated the uptake of PFAS into garden produce irrigated with PFAS-impacted groundwater. Water from a well at a local North Pole farm was found to contain PFOA and PFOS at a total of 16 parts per trillion (ppt). DEC collected samples from 14 types of fruits and vegetables. The study found that some PFAS can be taken up and accumulate in fruits and vegetables irrigated with water containing PFAS. DHSS determined the hazard associated with exposure to PFAS through eating vegetables and strawberries grown at the local farm is negligible.

Fish: Three rainbow trout from Kimberly Lake, north of the former refinery, were collected and submitted to a commercial laboratory for PFAS analysis in 2018. All three fish were found to contain elevated levels of two PFAS: perfluorononanoic acid (PFNA) and perfluorooctane sulfonic acid (PFOS). Kimberly Lake was closed to fishing in April 2019 by the Alaska Dept. of Fish & Game (ADF&G) because of PFAS levels found in fish. The ADF&G released an emergency order closing Kimberly Lake to sport fishing at that time. As of May 1, 2023, ADF&G has restricted Kimberly Lake to catch-and-release fishing only for all fish species. More information may be found by following the links below.

In 2013, Badger Slough and seven gravel ponds, including Kimberly Lake, were sampled for sulfolane. Sulfolane was not detected in any of the surface water samples. Sulfolane is known to degrade readily in environments with an adequate supply of oxygen, like gravel ponds.

Groundwater Advisory: In November 2018, DEC issued 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 polyfluoroalkyl substances, known as PFAS.

The advisory assists residents in avoiding unintentional contact with, or spreading of, the chemicals present in well water. DEC advises against using untreated, contaminated well water for all use, including but not limited to drinking, cooking, bathing, or household uses, as well as gardening, lawn watering, car and equipment washing and other outdoor uses. Bringing contaminated well water to the surface may expose people and animals to chemicals in the water. Using contaminated well water may also allow chemicals in the water to spread onto other properties, sloughs, or ponds. In issuing this advisory, DEC is seeking the community’s assistance in minimizing the future spread of these contaminants. For those wishing to use well water, DEC recommends treatment to remove both sulfolane and PFAS. DEC is available to provide guidance on this question.

If you are concerned you may have sulfolane or PFAS in your well water, DEC has prepared fact sheets to provide step-by-step advice for testing your water. DEC recommends you contact Zuzana Culakova, Chemist, DEC Contaminated Sites Program at 907-465-5346, or the Contaminated Sites Program at 907-451-2143 if you have any questions about testing.

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Department of Environmental Conservation

Mailing Address:  P.O. Box 111800
Juneau, Alaska 99811
Location:  410 Willoughby Avenue, Juneau