9 December 2022

Illinois Pollution Control Board Poised To Adopt Regulations Establishing PFAS Groundwater Standards

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The Illinois Pollution Control Board is currently considering proposed amendments to the Illinois Part 620 groundwater regulations that would establish the first enforceable PFAS standards...
United States Environment
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The Illinois Pollution Control Board is currently considering proposed amendments to the Illinois Part 620 groundwater regulations that would establish the first enforceable PFAS standards under Illinois law. The rulemaking proposal, filed by the Illinois Environmental Protection Agency on December 8, 2021, would establish groundwater standards for six (6) per- and polyfluoroalkyl substances (PFAS).

 The PFAS standards were included in proposed amendments to Illinois' Part 620 groundwater quality regulations, 35 Ill. Adm. Code Part 620, which provides a broader range of proposed updates and modifications to the groundwater standards.1 The Part 620 groundwater standards are also utilized in the state's risk-based remediation regulations, the Tiered Approach to Corrective Action (TACO) regulations at 35 Ill. Adm. Code Part 742, used to set standards under remedial programs such as the Site Remediation Program (SRP) regulations, 35 Ill. Adm. Code 740, and the Leaking Underground Storage Tank (LUST) Regulations, 35 Ill. Adm. Code 734.

The proposed amendments would establish standards for the following PFAS compounds:

1) Perfluorobutane Sulfonic Acid (PFBS)

2) Perfluorohexane Sulfonic Acid (PFHxS)

3) Perfluorononanoic Acid (PFNA)

4) Perfluorooctanoic Acid (PFOA)

5) Perfluorooctane Sulfonic Acid (PFOS)

6) Hexafluoropropylene oxide dimer (HFPO-DA, also known as GenX).

In addition, the proposal would classify PFOA as a carcinogen based on its 2B classification by the World Health Organization's International Agency for Research on Cancer ("IARC"), which means that it is considered possibly carcinogenic to humans.

PFAS are a class of over 5,000 manufactured chemicals discovered in the late 1930s, and they have been widely manufactured since the 1950s. Often referred to as "forever chemicals," PFAS are highly stable in the environment and detected at very low concentrations (parts per trillion). Due to their unique physical and chemical properties, they have been used in a wide range of applications, including firefighting foams, consumer products, fast food wrappers and containers, and industrial processes. Because of their widespread use, PFAS have become ubiquitous in the environment, and these proposed standards will make site cleanups more complex and expensive.

Illinois EPA previously conducted a state-wide drinking water survey that documented PFBS, PFHxS, PFOS, and PFOA detections in finished water of public water supplies. Similarly, HFPO-DA, or GenX, was detected during other groundwater sampling.

The following table reveals the proposed Class I and Class II standards for each PFAS compound:


Proposed Class I Standard in mg/L or ppm (ng/L or ppt)

Proposed Class II Standard in mg/L or ppm (ng/L or ppt)

Hexafluoropropylene oxide dimer acid, (HFPO-DA, GenX)





Perfluorobutane Sulfonic Acid (PFBS)

0.0012 (1,200)

0.0012 (1,200)

Perfluorohexane Sulfonic Acid (PFHxS)

0.000077 (77)

0.000077 (77)

Perfluorononanoic Acid (PFNA)

0.000012 (12)

0.000012 (12)

Perfluorooctanoic Acid (PFOA)

0.000002 (2)

0.000002 (2)

Perfluorooctane Sulfonic Acid (PFOS)

0.0000077 (7.7)

0.0000077 (7.7)

As a review of the table shows, the Class II standards are, for all PFAS compounds, identical to the Class I standard. 

The Pollution Control Board held public hearings on the rulemaking proposal on March 9, 2022, and June 21, 2022. These first two hearings focused on IEPA's testimony in support of the proposal and questions from participants. The third and final round of hearings is currently scheduled for December 7, 2022, continuing to December 8, 2022, if necessary, and will focus on testimony from other interested parties

Illinois' move to adopt PFAS standards follows a growing trend in states across the country, with at least 20 other states proposing or adopting standards. Given that no enforceable drinking water standards for PFAS have been adopted at the federal level, many states have established their own PFAS regulations. The resulting state efforts have created a patchwork of regulations, with standards that can vary widely from state to state. However, there is also action at the federal level, with USEPA proposing to list PFOA and PFOS as hazardous substances under CERCLA. This would require Toxic Release Inventory (TRI) reporting for 172 PFAS compounds and public water supply systems to monitor for certain PFAS under its  Fifth Unregulated Contaminant Monitoring Rule.

For more information, please see the following industry alerts:

At Dickinson Wright, we have been leaders on PFAS issues and are prepared to assist clients in navigating the evolving developments in this field. We will continue to monitor these proceedings as they unfold.


1. Among other things, the proposed regulations establish standards for 10 new chemicals, including the 6 PFAS compounds, three (3) inorganic constituents (aluminum, lithium, and molybdenum), and 1 polycyclic aromatic hydrocarbon (1-methylnapthalene). Three new atrazine metabolites are also added, with atrazine being treated as a complex mixture. The proposal would also replace the groundwater quality standards for radium 226 and 228 with a combined 226+228 standard.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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