Read the full article by Laura Rabinow (Rockefeller Institute of Government)

“On March 14th, 2023 the Environmental Protection Agency (EPA) proposed new drinking water regulations for six perfluoroalkyl and polyfluoroalkyl substances (PFAS) chemicals, the first such proposal for any PFAS. PFAS are human-made and have been manufactured and used in the United States for over 80 years to make a broad array of consumer and industrial products. They have been shown to be toxic, persistent, and bioaccumulative, which means they can build up over time in someone’s body. PFAS exposure through contaminated drinking water has been linked to several negative health outcomes, including various forms of cancer.

The Biden Administration’s PFAS Strategic Roadmap had previously indicated that proposed standards would be developed for PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid). However, EPA Administrator Michael Regan announced individual standards or limits of 4 ppt (parts per trillion) each for PFOA and PFOS, and the use of a combined hazard index to regulate four additional PFAS chemicals: HFPO (also known as GenX), PFNA, PFHxS, and PFBS. These proposed standards are a significant and long-awaited step to putting in place enforceable public health protections for PFAS, the broader class of chemicals commonly referred to as ‘forever chemicals.’

As detailed in our earlier report on PFAS drinking water standards, ‘Parts per Trillion,‘ if finalized, they will represent the first new federal drinking water standards for any contaminant since 1996, when the current process for establishing such standards was enacted. To date, there has been no federal drinking water standard for any PFAS chemicals.

In this blog, we discuss how the regulations proposed on Tuesday came to be, the impact on standards established at the state level, and potential future developments for the regulation of PFAS chemicals.

How We Got to Today: PFAS Rulemaking

The rulemaking process for establishing federal drinking water standards is especially lengthy, but the pace of regulatory processes at both the state and federal level generally don’t align with the large universe of potential PFAS contaminants. PFOA and PFOS and the other four compounds under this newly proposed federal regulation are just a handful of the more than 9,000 (and growing) human-made PFAS compounds. Short of regulating more PFAS together as a group or class, it would likely take many lifetimes to address all PFAS compounds.

The formal pathway to regulation generally begins when potential contaminants are placed on the Contaminant Candidate List (CCL) based on their potential health impacts and how frequently they are known or anticipated to be found in water systems. PFOA and PFOS were first included on CCL 3 in 2009 and again on CCL 4 in 2016.

Contaminants from the CCL may then be selected for further evaluation and data collection through the Unregulated Contaminant Monitoring Rule (UCMR) process. This process includes the nationwide testing of drinking water systems to determine how frequently and at what levels a contaminant may occur in drinking water systems. PFOA and PFOS were included on the Third UCMR list in 2012, the testing for which was conducted between 2013 – 2015.

Based, in part, on the occurrence data collected through the UCMR process, a final determination was made to take further regulatory action to establish drinking water standards in 2021. This led to the proposed rule announced on March 14, 2023. The rule will now be subject to a public comment period before being finalized. The EPA noted that it anticipates that finalization by the end of 2023.

Until now, the EPA has issued health advisory levels (HALS) starting in 2009, and then again in 2016 and 2022. These levels are non-enforceable and act as guidance to states if and as they develop their own advisories or standards for short-term to lifetime exposures. In June 2022, the EPA issued interim updated drinking water health advisory levels (HALs) for PFOA and PFOS, at 0.004 ppt and 0.02 ppt, respectively—orders of magnitude lower than the previous advisories and existing state standards.

What Will Be the Impact on State Drinking Water Standards?

Since the EPA’s 2016 health advisory level of 70 ppt combined for PFOA and PFOS, several states have established enforceable regulatory standards for PFAS chemicals in drinking water. While all the current state standards are well below both the EPA’s 2009 and 2016 health advisory levels, the federal standards proposed on March 14, 2023, for PFOA and PFOS are lower than any of these existing state standards for individual PFAS. Once finalized, all states will be required to make their regulations at least as protective as those federal standards. The inclusion of six compounds in the proposed regulations, and the use of a hazard index to set a combined level for four of them mirrors regulatory approaches already observed at the state level. Our chemical regulatory systems have been dominated by a one-by-one approach which sets limits for compounds individually. In contrast, the use of a combined hazard index, which limits the levels of multiple co-occurring compounds at once, is one means to address the potential effects that toxic or hazardous chemicals may have when they are found together and interact with each other in a dynamic environment.

A number of factors contribute to the variation between the standards set by the states and the newly proposed federal standards. Regulations are developed considering a range of variables and different oversight bodies may make different choices for the variables in calculating standards. Variations across standards reflect those different choices of variables within the underlying calculations of the levels that are determined to be protective of public health impacts. This includes: which health impacts are considered; which vulnerable populations are deemed of most concern; how much of a person’s exposure to a contaminant is estimated to come from a particular source (referred to as the relative source contribution); and which uncertainty factors are applied to account for the degree to which we don’t know, lack data on, or are extrapolating data from one type of subject to another. In this case, the different choices have meant that the EPA’s health-based values and goals were orders of magnitude lower than state-level calculations.

In addition, ‘environmental standards do not only reflect health impacts but technological capacity and decisions about ensuring production.‘ That is, standards are not necessarily set at those health-based levels or the maximum contaminant level goal (MCLG). There is sometimes (even often) a gap between those lower health-based values and goals, and the resultant standard. In the case of the new EPA proposal, this gap is reflected in the difference between the MCLG of 0 ppt for PFOA and PFOS, and the proposed standard of 4 ppt each. This difference has been driven by technological limits. The EPA has previously determined the lowest level at which most labs across the country can reliably test down PFOA and PFOS is 4 ppt.”…