Sulfolane

Research Overview

Status: Ongoing
Substances: Sulfolane
Nominated: September 2011

Background Information

Sulfolane is a highly water-soluble solvent commonly used for refining natural gas and petroleum and was found in contaminated groundwater and well water in North Pole, Alaska, near a petroleum refinery in 2009. Water contaminated with sulfolane also has been identified in other natural gas or petroleum refining sites.

Because it moves into groundwater, the potential for human exposure to sulfolane through drinking water is high. Exposure may also occur through inhalation or skin contact for those who work in industries using sulfolane.

NTP Studies & Findings

NTP is performing a set of studies to evaluate the toxicity of sulfolane.

What did the studies find?

See the table below for the most up-to-date information on the variety of projects taking place at NTP.

List of sulfolane studies
Study	Description	Status	Findings & Supporting Files
Absorption, distribution, metabolism, and excretion	Animal studies to investigate how well sulfolane was absorbed into the body, where it circulated in the body, and how it was cleared following oral administration and skin application.	Completed	Findings: In male and female rats and mice, sulfolane was well absorbed when given orally; the dose showed up in high amounts in the circulatory system when a high dose was administered orally Sulfolane applied to the skin was absorbed more readily in mice than in rats Sulfolane was eliminated rapidly, with urine as the main excretion route in both rats and mice of both sexes Supporting files: Waidyanatha et al. 2019a Waidyanatha et al. 2019b Silinski et al. 2019
28-day toxicity study	Studies in multiple animal species to determine species sensitivity.	Completed	Supporting files: Shipkowski et al. 2021 Data tables
Subchronic toxicity study	Three-month studies to identify effects on various endpoints, including development and reproduction in rats and mice.	Ongoing	N/A
Chronic toxicity study	Studies to determine the effects of long-term exposure on rats and mice, including any potential carcinogenic effects.	Ongoing	N/A
Immunotoxicity study	Rat and mouse studies to determine the potential of sulfolane to effect immune system function.	Completed	Supporting files: AtLee et al. 2021 Data tables

Research at Other Agencies

United States

Alaska
- Health Consultation: Sulfolane Plume in Groundwater: Evaluation of Community Concerns About Sulfolane in Private Water Wells
- North Pole Refinery Project Documents – This website contains many resources on sulfolane, including fact sheets, newsletters, press releases, FAQs, and reports regarding drinking water, site characterization and remediation, and human health and toxicology.
US Environmental Protection Agency: National Center for Environmental Assessment
- Provisional Peer-Reviewed Toxicity Values for Sulfolane
US Centers for Disease Control and Prevention: Agency for Toxic Substances and Disease Registry
- Health Consultation - Sulfolane, 2010
- Health Consultation - Sulfolane, 2011

Informational Resources

Nominations

Presentations

NTP Board of Scientific Counselors Meeting, Research Triangle Park, NC, December 2011
- Research Concept: Sulfolane
- Slides: Sulfolane

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