Illinois EPA Issues Health Advisory for 6:2 FTS in Groundwater

Nov ember 24, 2025 K im Biggs, Il linois EP A FOR IMMEDIA TE RELEASE 217 -558- 1536 kim.bigg s @illinois.gov Illinois EP A Iss ues Health Advisor y for 6:2 Fluorotelomer Sulfonic Acid Chemical Identifi ed Thr ough P er - and P oly fluoro alkyl Substa nces (PF AS) Sampling of Community Wa ter Supplies Springfield – Illinois Environmental Protection Agency Acting Director James Jennings announced the issuance of a health advisory for the PFAS 6:2 Fluorotelomer Sulfonic Acid (6:2 FTS), in accordance with Illinois groundwater regulations. Health advisories are issued when there is detection of a chemical substance(s) harmful to human health for which no numeric groundwater standard(s) exists, and resampling confirms the presence in a community water supply well. “Through Illinois EPA’s proactive statewide sampling of PFAS chemicals in Illinois Community Water Supplies, we have identified chemicals that present potential public health impacts and developed health advisories to ensure the public has clear, sc ience-driven information about potential exposures and associated risks from these chemicals. Health advisories, like the 6:2 FTS advisory, also provide community water supplies important information to determine whether any additional protective steps are warranted, ” said Acting Director Jennings. “ The Illinois EPA considers established health advisories when groundwater cleanup and action objecti ve s are established for any of its regulatory programs. ” Health advisories are published in the Environmental Register, a publication of the Illinois Pollution Control Board, and placed on the website: https://pcb.illinois.gov/Resources/News. The health advisories are also available on the Illinois EPA website at: https://epa.illinois.gov/topics/water- quality/pfas/pfas-healthadvisory.html. Since 2021, Illinois EPA has issued health advisories for eight chemicals included in the family of PFAS, often referred to as “forever chemicals” because of their persistence over time in surface water and groundwater. Some of those health advisories were updated to account for new scientific information. Each health advisory contains a general description of the chemical, information on carcinogenicity and potential adverse health effects, and a guidance level. The following table provides a summary list of all Illinois EPA Health Advisories currently in effect. The guidance level contained in each of the health advisories is not an enforceable groundwater or dr inking water standard. - m or e -

6:2 FT S Health Advisory/2 Chemical Abstr act Ser vices Registry Number (CASRN) Substance Name Substance Acrony m HA Guidance Level in milligr ams per liter (mg/L) HA Guidance Level in nanogr ams per liter (ng/L) Date HA Iss ued/ *Revised 27619- 97 -2 6:2 Fluoro telomer Sulfonic Acid 6:2 FTS 0.00077 770 11/6/25 375 - 22 - 4 P erfluorobutanoic Acid PFBA *0.00 38 3,8 00 *4 / 11 / 25 307 - 24 - 4 P erfluorohexa noic Acid PFHxA *0.00 19 *1,9 00 *4/11/25 *Updated health advisory guidance level To ensure that Illinois’ groundwater quality standards match current scientific data and methodologies, Illinois EPA proposed, and the Illinois Pollution Control Board (Board) adopted, amendments to the Board ’s groundwater quality regulations to establish new groundwater quality standards for PFAS analytes in which Illinois EPA had previously issued health advisories. Those PFAS are perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS), pefluorononanoic acid (PFNA), perfluorooctanesulfonic acid (PFOS), and perfluorooctanoic ac id (PFOA). Therefore, the groundwater quality standards for these PFAS analytes replace the previously issued health advisories. A groundwater quality standard was also established for hexafluoropropylene oxide dimer acid, also known as GenX (HFPO-DA). In 2021, the Illinois EPA completed a statewide PFAS investigation, which sampled drinking water at every community water supply in Illinois. If PFAS chemicals were confirmed at concentrations above laboratory minimum reporting levels, the Illinois EPA worke d directly with those comm unity water supplies to ensure residents were inform ed and determined next steps for reducing exposure. Many community water supplies continue to sample for PFAS chemicals, which is how the r ecent detections were made. A complete listing of sample results from the statewide investigation is available on the interactive map established by Illinois EPA at: https://illinois- epa.maps.arcgis.com/apps/dashboards/bd611162a7f74cfe88b6928c926416c3. Further, from 2023- 2025, U.S. EPA is conducting PFAS testing in the State of Illinois under the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) which is available at: https://www.epa.gov/dwucmr/fifth- unregulated-contaminant-monitoring-rule-data-finder#data-finder. ###