The Illinois Environmental Protection Agency (IEPA) released new proposed groundwater quality standards for select per- and polyfluoroalkyl substances (PFAS). The new standards were released as a discussion draft of proposed amendments to the groundwater quality rules under 35 Ill. Adm. Code Part 620, regulating the following PFAS types:
||Standard in mg/L or ppm
||Standard in ng/L or ppt
|Perfluorobutane Sulfonic Acid (PFBS)
|Perfluorohexane Sulfonic Acid (PFHxS)
|Perfluorononanoic Acid (PFNA)
|Perfluorooctanoic Acid (PFOA)
|Perfluorooctane Sulfonic Acid (PFOS)
|Total PFOA and PFOS in any combination
As currently proposed, these standards would apply to both Class I (known as “Potable Resource”) and Class II (known as “General Resource”) groundwater. According to IEPA, the proposed groundwater values are exclusively health-based and, unlike more typical Maximum Contaminant Level (MCL) standards, do not consider treatability and cost. As of the date of this article, the rules are still in discussion draft form, and have yet to be proposed for adoption through the formal rulemaking process before the Illinois Pollution Control Board (IPCB).
PFAS are a class of over 5,000 chemicals that were discovered in the late 1930s, and they have been widely manufactured since the 1950s. PFAS are highly stable in the environment and can be detected at very low concentrations. Due to their unique physical and chemical properties, they have been used in a wide range of applications, including firefighting foams, consumer products and industrial processes.
Illinois’ move to adopt PFAS standards follows an ever-growing trend across the country. Given that an enforceable federal drinking water standard for PFAS remains lacking, PFAS regulation has largely fallen to the states, creating a patchwork of regulation that is actively shifting in real time. Even if the EPA comes forward with enforceable federal standards in the near future, those standards are likely to be limited to PFOS and PFOA, two of the more widely used and studied PFAS compounds which would still leave a regulatory quagmire in place for all other PFAS chemicals that states choose to regulate. For context, the EPA’s “Master List of PFAS Substances” lists 5,070 chemicals as of the date of this article. For the handful of other PFAS that are currently regulated at the state level, standards for specific PFAS types can vary wildly between regulating states. Take, for example, PFBS: while Illinois’ proposed standard is 0.14 mg/L (or 140,000 ng/L), Michigan’s recently enacted standard is set at 0.00042 mg/L (or 420 ng/L).
Aside from the actions of other states, political pressure for action on PFAS has also been mounting within Illinois. On March 10, United States Senators Durbin and Duckworth and Congresswoman Cheri Bustos sent a letter to the EPA Region 5 Administrator Kurt Thiede urging air emissions testing for PFAS “at manufacturing facilities and other industrial sources known to emit [PFAS] in Illinois,” including a specific hazardous waste incinerator facility in Sauget, Illinois. The letter’s focus on PFAS air emissions is particularly noteworthy, illustrating that PFAS regulation has the potential to expand beyond groundwater quality standards.
 Standard given in milligrams per liter (mg/L) or parts per million (ppm).
 Standard given in nanograms per liter (ng/L) or parts per trillion (ppt).
 The rules define Class I Potable Resource Groundwater at 35 Ill. Adm. Code 620.210. Please see pages 12 and 13 of the draft rules for the proposed amendments to this rule.
 The definition of Class II General Resource Groundwater may be found at 35 Ill. Adm. Code 620.220.