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PFAS Statewide Health Advisory

​On January 28, 2021, Illinois EPA issued four statewide Health Advisories for Per- and Polyfluoroalkyl Substances (PFAS) as a result of an ongoing sampling investigation of PFAS chemicals in Illinois community water supplies. A Health Advisory is a regulatory action that provides guidance to local officials and community water supply operators in protecting the health of water consumers. Illinois EPA is authorized to issue a Health Advisory when there is a confirmed detection in a community water supply well of a chemical substance for which no numeric groundwater standard exists.

On April 16, 2021, Illinois EPA issued a statewide Health Advisory for a fifth PFAS as a result of an ongoing sampling investigation of PFAS chemicals in Illinois community water supplies. In addition, on April 16, 2021, Illinois EPA updated its statewide Health Advisory for perfluorobutanesulfonic acid (PFBS). This update is due to updated toxicity assessments, resulting in an updated Health Advisory Guidance Level. 

In accordance with Illinois groundwater regulations, Illinois EPA added an additional statewide Health Advisory for perfluorononanoic acid (PFNA) on July 27, 2021.

Illinois EPA uses methodology and toxicity data, outlined in 35 Illinois Administrative Code Part 620, to derive health based protective values. For the development of Health-Based Guidance Levels for PFHxS, PFOS, and PFOA, Illinois EPA relied upon draft toxicity values developed by the Agency for Toxic Substances and Disease Registry (ATSDR). On May 5, 2021, ATSDR issued its final Toxicological Profile for Perfluoroalkyls, which was used to develop the Health-Based Guidance Level for PFNA. The draft dose-minimum risk levels (dose-MRLs) referenced in the Health Advisories for PFHxS, PFOS, and PFOA are now final values. On April 10, 2023, U.S. EPA's Integrated Risk Information System (IRIS) published its final toxicity assessment for perfluorohexanoic acid (PFHxA), resulting in Illinois EPA’s issuance of an updated PFHxA Health-Based Guidance Level.   

At this time, no enforceable federal or state drinking water standard, called a Maximum Contaminant Level or MCL, exists for any of the more than 5,000 known PFAS chemicals. Illinois EPA is in the process of collecting data in the PFAS Investigation Network to develop a state MCL. 

The table below shows the PFAS chemicals for which Illinois EPA has established Health Advisories.

Chemical Abstract Services Registry Number (CASRN)
PFAS Analyte
Acronym Health-Based Guidance Level 
Date Health Advisory Issued/Revised
​Perfluorononanoic acid
​July 27, 2021
​​Perfluoroctanesulfonic acid
​April 16, 2021
​Perfluorobutanesulfonic acid ​PFBS ​2,100*
​April 16, 2021
​Perfluorooctanoic acid
​January 28, 2021
Perfluorohexanesulfonic acid
​January 28, 2021
​Perfluorohexanoic acid
​April 26, 2023

  *Health-Based Guidance Level per April 16, 2021 PFBS Health Advisory Update. 

**Health-Based Guidance Level per April 26, 2023 PFHxA Health Advisory Update.

Health Advisories serve several purposes as outlined 35 Ill. Adm. Code 620.601(a) – (d).  Health Advisories are to be used by the Illinois EPA when evaluating groundwater cleanup, when developing future rulemaking proposals, evaluating mixtures of chemical substances and when determining whether a community water supply is taking its raw water from a site or source consistent with regulatory requirements. In addition to the uses outlined in the regulations, the Health Advisories also contain general information on the characteristics of the harmful contaminant, potential adverse health effects and numerical contaminant guidance levels.  The guidance levels contained in the Health Advisories represent concentrations in drinking water at which no adverse health effects are expected to occur.  Additional information on the potential health impacts of PFAS can be found on our Per- and Polyfluoroalkyl Substances (PFAS) webpage.

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