The discovery of sulfolane in drinking water wells in 2009 near the North Pole Refinery, about 15 miles east of Fairbanks, has led to an extensive groundwater investigation. Flint Hills Resources of Alaska, owner of the refinery, responded quickly by providing affected residents with alternate drinking water. Sulfolane is an emerging contaminant, therefore, the long-term health effects from exposure through drinking water are not yet understood. The groundwater plume is approximately 2.5 miles wide, 3 miles long and nearly 300 feet deep, making it one of the largest in the state, with many private properties impacted. Currently nearly 300 alternate drinking water supplies have been installed in the affected properties. For additional details, see Frequently Asked Questions.
- State Approves Cleanup Plan for North Pole Refinery: The Alaska Department of Environmental Conservation (DEC) and the Department of Law announced on October 20, 2014, that the State has approved a cleanup plan proposed by Flint Hills Resources for contaminated soil and groundwater at its North Pole refinery property.
The cleanup actions included in the plan are designed to protect onsite workers and reduce migration of contaminants. Cleanup measures include treating groundwater, recovering fuel and other contaminants from groundwater, and excavating contaminated soil from certain areas.
The plan also memorializes management practices for a future owner of the property and limits future use to industrial operations in order to prevent contact with the remaining contamination.
Cleanup Level Review: On April 4, 2014, the DEC Commissioner asked the Division of Spill Prevention and Response to further document the rationale and re-evaluate the information that led to the selection of a site-specific cleanup level for sulfolane. This evaluation is expected to be completed by the end of 2014.
To ensure the most scientifically sound groundwater cleanup level for sulfolane, DEC sought the input of independent, national experts through a panel convened by Toxicology Excellence for Risk Assessment (TERA). TERA selected, organized, and conducted the panel discussion, choosing the members based on their expertise and screening them for any conflicts of interest. See TERA's website on the Independent Expert Peer Review of Sulfolane Reference Doses for ADEC.
The experts met in Fairbanks September 16-17 to review the available reference doses for sulfolane. A reference dose is a toxicity value and a key component used by DEC in establishing a cleanup level for the groundwater. The panel selected by TERA was comprised of national experts in toxicology, immunology, risk assessment, and contaminated sites. The public was invited to observe the two-day deliberations on relevant scientific issues related to the reference doses. This process and the results will help assure DEC utilizes the most scientifically defensible reference dose when calculating a groundwater cleanup level for sulfolane.
A report summarizing the panel’s recommendations will be submitted to DEC, likely in early December, and it will be considered as part of the decision on a cleanup level for sulfolane. DEC’s decision on a cleanup level is expected by the end of 2014.
TERA is an independent non-profit organized for scientific and educational purposes. TERA describes its mission as supporting the protection of public health by developing, reviewing and communicating risk assessment values and analyses; improving risk methods through research; and educating risk assessors, managers, and the public on risk assessment issues. For more information, please visit their website.