Understanding PFAS: Why a broad, transparent PFAS Testing Strategy is needed

Maria Doa, Senior Director, Chemicals Policy; Lauren Ellis, Research Analyst; and Lariah Edwards, Post-Doctoral Fellow

EDF this week sent EPA a letter identifying opportunities for the agency to improve the effectiveness and transparency of its strategy for testing per- and polyfluoroalkyl substances (PFAS).

EPA unveiled its National PFAS Testing Strategy (Testing Strategy) last fall, laying out its plan to better understand the class of chemicals and inform its future regulatory efforts. PFAS are a large group of synthetic chemicals used to impart water, oil, grease, and stain resistance to various materials, and they are used in hundreds of everyday products, from water-proof clothing to grease-proof food packaging. By its own count, EPA says there are more than 12,000 individual PFAS.

In their letter to EPA, EDF analyst Lauren Ellis and post-doctoral fellow Lariah Edwards commended the agency for developing a strategy to address some of the significant data gaps that exist around PFAS and committing to use its authority under the Toxic Substances Control Act (TSCA) ‒ the country’s main chemical safety law ‒ to require manufacturers to provide toxicity data on the chemicals.

As the letter points out, however, in its current state, the Testing Strategy lacks sufficient detail and is too narrow to fulfill the agency’s intended purpose to understand and regulate PFAS in a way that is protective of both human health and the environment.

PFAS have been dubbed “forever chemicals” because they do not easily break down and are extremely persistent in the environment. They have been detected across the country, in California well-water, milk from Maine dairy farms, and even raining down around the Great Lakes. As such, it is critical that EPA not delay action to reduce exposures to this class of chemicals as it develops information through the Testing Strategy.

What we have learned about the health and environmental effects associated with a small set of these chemicals is troubling, revealing serious concerns about PFAS’ toxicity and their potential to bioaccumulate in plants, animals, and humans. Given the established threat of PFAS such as PFOA and PFOS, as well as some of their replacements like GenX, many people, particularly in communities exposed to multiple PFAS, are legitimately concerned about the potential risks presented by the entire class.

This makes it vitally important to develop an effective and health protective strategy for testing PFAS. The following are six steps the EPA can and should take to enhance its Testing Strategy:

1. Adopt a broader definition of PFAS. The current strategy applies an overly narrow definition of PFAS, representing approximately 2,350 substances, or about one in five of the more than 12,000 individual PFAS that EPA has identified. EPA should modify its definition of what constitutes a PFAS to include any chemical substance containing at least one fully fluorinated carbon atom. Such a definition is consistent with that used by other authoritative bodies in the United States and around the world, such as the OECD.
2. Provide more detail on core elements of the strategy. EPA intends to initially test only 24 “candidate” PFAS that represent the 2,350 substances covered under the Testing Strategy, but it does not sufficiently explain how each candidate substance represents the types of PFAS in their respective category or why certain types of PFAS were excluded from consideration. EPA needs to provide more detail on the methodology it used to exclude certain types of PFAS from the strategy through five “structural filters” and list all PFAS excluded under each filter.
3. Include additional PFAS for testing. We believe EPA’s plan to initially test 24 candidate PFAS is insufficient. This small number of candidates introduces uncertainties which EPA has not characterized and may exclude from testing many types of PFAS that communities are exposed to.
4. Consider cumulative risk from the combined effects of PFAS. EPA said in its draft framework for estimating non-cancer risks from PFAS mixtures that it intends to address potential toxicity from different mixtures of PFAS. In this approach, the combined exposure to more than one PFAS is assumed to be additive. While we commend the agency for its stated intention to consider exposures to mixtures of PFAS, the Testing Strategy itself should require testing on PFAS mixtures to better understand whether the effects from multiple PFAS are always simply additive or whether they have more than additive or “synergistic” effects. Mixture testing across a wide range of PFAS combinations is needed. EPA should require companies to conduct tests on PFAS mixtures to better understand the health effects.
5. Modify the role of new approach methods (NAMs) and proceed to whole organism testing. The Testing Strategy relies heavily on NAMs to determine whether candidate PFAS will be tested in vertebrate animal-based tests. While we appreciate EPA’s efforts to move toward reducing the use of vertebrate animal testing, the agency does not discuss how it will evaluate results from NAMs or how it will address uncertainties and limitations associated with these predictive methods. With such massive data gaps and only a subset of chemicals to be tested, EPA should go directly to whole organism testing.
6. Outline how PFAS data will be used. EPA should describe how it intends to use the data it receives and generates under the strategy to characterize and manage risks from PFAS, as well as how it plans to make health and safety information on PFAS publicly available and accessible.

EPA’s stated purpose of the Testing Strategy is to “…deepen understanding of the impacts of PFAS, including potential hazards to human health and the environment …. [and to] help EPA identify and select PFAS for … testing using [the] Toxic Substances Control Act (TSCA)….” We hope the recommendations included in EDF’s letter to EPA can be used to help the agency increase the scope and transparency of its Testing Strategy.