PFAS Statewide Health Advisory

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. Illinois EPA issued Statewide Health Advisories for seven individual PFAS confirmed in community water supply wells as a result of sampling investigations of community water supply wells.

Health Advisories serve several purposes as outlined in 35 Ill. Adm. Code 620.601(a) – (d). Health Advisories are to be used by the Illinois EPA when:

evaluating groundwater cleanup;
developing future rulemaking proposals;
evaluating mixtures of chemical substances; and
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 health-based guidance levels (HBGLs) 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.

Below is a summary of PFAS analytes with Statewide Health Advisories. The levels are presented in nanograms per liter (ng/L), equal to parts per trillion (ppt). For reference:

Perfluorobutanesulfonic Acid (PFBS) CASRN 375-73-5

Illinois EPA issued an initial Statewide Health Advisory for PFBS on January 28, 2021, and updated the health advisory on April 16, 2021, using updated toxicity data. The updated health-based guidance level is 2,100 nanograms per liter (ng/L) or ppt and is calculated with toxicity data published as a U.S. EPA Provisional Peer-Reviewed Toxicity Value (PPRTV) April 2021.

Perfluorobutanoic Acid (PFBA) CASRN 375-22-4

Illinois EPA issued a Statewide Health Advisory for PFBA on September 16, 2024. The health-based guidance level is 7,000 nanograms per liter (ng/L) or ppt and is calculated with toxicity data published by U.S. EPA Integrated Risk Information System (IRIS) December 2022.

Perfluorohexanesulfonic Acid (PFHxS) CASRN 355-46-4

Illinois EPA issued a Statewide Health Advisory for PFHxS on January 28, 2021. The health-based guidance level is 140 nanograms per liter (ng/L) or ppt and is calculated with toxicity data published by the Agency for Toxic Substances and Disease Registry (ATSDR) May 2021.

Perfluorohexanoic Acid (PFHxA) CASRN 307-24-4

Illinois EPA issued an initial Statewide Health Advisory for PFHxA on January 28, 2021, and updated the health advisory on April 26, 2023, using updated toxicity data. The updated health-based guidance level is 3,500 nanograms per liter (ng/L) or ppt and is calculated with toxicity data published by U.S. EPA Integrated Risk Information System (IRIS) April 2023.

Perfluorononanoic Acid (PFNA) CASRN 375-95-1

Illinois EPA issued a Statewide Health Advisory for PFNA on July 27, 2021. The health-based guidance level is 21 nanograms per liter (ng/L) or ppt and is calculated with toxicity data published by ATSDR May 2021.

Perfluorooctanesulfonic Acid (PFOS) CASRN 1763-23-1

Illinois EPA issued a Statewide Health Advisory for PFOS on April 16, 2021. The health-based guidance level is 14 nanograms per liter (ng/L) or ppt and is calculated with toxicity data published by ATSDR May 2021.

Perfluorooctanoic Acid (PFOA) CASRN 335-67-1

Illinois EPA issued a Statewide Health Advisory for PFOA on January 28, 2021. The health-based guidance level is 0.6 ng/L or ppt and is calculated with cancer toxicity data published by California EPA Office of Environmental Health Hazard Assessments (OEHHA) August 2019. As the health-based guidance level is less than PFOA’s minimum reporting level (MRL) of 2 ng/L for drinking water analysis, the health advisory guidance level is the MRL of 2 nanograms per liter (ng/L) or ppt, per Section 620.605(b)(2).

Illinois EPA calculates HBGLs for all PFAS analytes for which sufficient toxicity information is available and accepted by U.S. EPA. The table below provides a summary of current PFAS HBGLs:

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CAS Registry Number	PFAS Analyte	Acronym	Health-Based Guidance Level (ng/L or ppt)	Health Advisory Issued (Yes/No)

* The HBGL is less than the minimum reporting level (MRL) of 2 ng/L; therefore, the MRL of 2 ng/L is the Health Advisory Level or Health Based Guidance Level.