EPA Seeks Information on PFAS for Possible Addition to TRI List of Toxic Chemicals
On December 4, 2019, the U.S. Environmental Protection Agency (EPA) published an advance notice of proposed rulemaking (ANPRM) soliciting information as EPA considers a future rulemaking to add certain per- and polyfluoroalkyl substances (PFAS) to the list of toxic chemicals subject to reporting under Section 313 of the Emergency Planning and Community Right-to-Know Act (EPCRA) and Section 6607 of the Pollution Prevention Act (PPA) (more commonly known as the Toxics Release Inventory (TRI)). 84 Fed. Reg. 66369. In the ANPRM, EPA outlines what PFAS are, why it is considering adding certain PFAS to EPCRA Section 313, what listing actions are being considered, who may be required to report, the current understanding of hazard concerns for PFAS, EPA’s hazard assessments on PFAS, and other information available on these chemicals. According to the ANRPM, in considering a chemical for addition to the EPCRA Section 313 list, EPA bases its listing decision on the chemical’s hazard (i.e., toxicity), not the risk (i.e., toxicity plus potential exposures) related to that chemical. EPA requests comment on which, if any, PFAS should be evaluated for listing, how to list them, and “what would be appropriate reporting thresholds given their persistence and bioaccumulation potential.” Lastly, EPA asks for any additional data to inform its evaluation and determination of which PFAS may meet the EPCRA Section 313 listing criteria. Comments are due February 3, 2020.
In the ANPRM, EPA states:
PFAS are synthetic organic compounds that do not occur naturally in the environment. PFAS contain an alkyl carbon chain on which the hydrogen atoms have been partially or completely replaced by fluorine atoms. The strong carbon-fluorine bonds of PFAS make them resistant to degradation and thus highly persistent in the environment. Some of these chemicals have been used for decades in a wide variety of consumer and industrial products. Some PFAS have been detected at high levels in wildlife indicating that at least some PFAS have the ability to bioaccumulate. Some PFAS can accumulate in humans and remain in the human body for long periods of time (e.g., months to years). As noted in EPA’s Action Plan, because of the widespread use of PFAS in commerce and their tendency to persist in the environment, most people in the United States have been exposed to PFAS. As a result, several PFAS have been detected in human blood serum. [References omitted.]
Reasons to Add PFAS to the TRI
EPA states that some PFAS may be toxic, persistent in the environment, and accumulate in wildlife and humans. Therefore, releases of some PFAS to the environment and potential human exposure may be of concern. According to EPA, one source of potential exposure to PFAS is releases from industrial facilities that manufacture, process, or otherwise use PFAS. EPA states that information on the releases and waste management quantities from such facilities could help it and the public identify some potential sources of exposure to PFAS. EPA notes that the TRI is a tool that EPA can use to collect such information. EPA notes that “adding certain PFAS to the TRI could help inform discussions related to risks to human health and the environment but the information collected through TRI, as previously indicated, would not capture all sources of PFAS releases.”
TRI Listing Actions Being Considered
According to EPA, there are currently approximately 600 PFAS that are manufactured (including imported) and/or used in the United States. The two PFAS that have been studied the most are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Due to the voluntary phaseout under the 2010/2015 PFOA Stewardship Program, PFOA and PFOS are no longer produced domestically by the companies participating in the Program. EPA states that PFOA and PFOS may still be produced domestically, imported, and used by companies not participating in the PFOA Stewardship Program, however, and that PFOA and PFOS may also be present in imported articles. According to EPA, PFAS such as hexafluoropropylene oxide (HFPO) dimer acid (Chemical Abstracts Service (CAS) Number 13252-13-6) and its ammonium salt (CAS Number 62037-80-3), both commonly referred to as GenX, and perfluorobutane sulfonic acid (PFBS) (CAS Number 375-73-5) and its salt potassium perfluorobutane sulfonate (CAS Number 29420-49-3)) are some examples of short-chain PFAS that have been developed to replace long-chain PFOA and PFOS, respectively. EPA states that “[c]ompared to PFOA and PFOS, most replacement PFAS tend to have less information available about their potential toxicity to human and ecological populations.” Through the ANPRM, EPA seeks information to determine which PFAS currently active in commerce have sufficient toxicity information available to meet the EPCRA Section 313(d)(2) listing criteria. EPA is considering whether to add any PFAS currently active in commerce for which hazard assessments show that they meet the listing criteria to the TRI. EPA notes that one factor it considers when determining whether to add a chemical to the TRI list of toxic chemicals is whether reporting would occur on the chemical if it were to be added.
In addition, for any PFAS that meet the listing criteria, EPA is considering adding these compounds to the list of chemicals of special concern (Section 372.28) and establishing lower reporting thresholds. EPA notes that in 1999, it lowered the reporting thresholds for persistent, bioaccumulative, and toxic (PBT) chemicals. For PBT chemicals, with one exception, EPA established two reporting thresholds -- 100 pounds for PBT chemicals and 10 pounds for highly PBT chemicals (i.e., those PBT chemicals with very high persistence and bioaccumulation values). According to EPA, certain PFAS “may have persistence and bioaccumulation properties similar to other PBT chemicals where even small amounts of release present a concern.” To capture “appropriately” release information of PFAS, EPA is considering reporting thresholds lower than the statutory thresholds of 25,000 pounds for manufacturing or processing and 10,000 pounds for otherwise using TRI-listed chemicals.
EPA states that PFAS that meet the ECPRA Section 313 listing criteria could be listed as individual chemicals or as members of PFAS chemical categories. EPA cites its “Health Effects Support Document for Perfluorooctane Sulfonate (PFOS),” which states that PFOS (CAS Number 1763-23-1) is commonly produced as a potassium salt (CAS Number 2795-39-3) and that, while the CAS Number given is for linear PFOS, the toxicity studies are commonly based on a mixture of linear and branched PFOS. Therefore, the reference dose (RfD) derived in the 2016 Health Effects Support Document applies to the total linear and branched PFOS. According to EPA, “[f]or PFOS it would seem appropriate to create a TRI chemical category that includes all linear and branched isomers of PFOS and any salts of PFOS.” EPA notes that PFOA has similar considerations, as may other PFAS that may warrant reporting as a category rather than as individually listed chemicals. According to the ANPRM, EPA may also consider establishing a single chemical category for all PFAS, although EPA acknowledges that “a single category would be of limited use since it would not provide any information about which PFAS are being released and/or managed as waste.”
The Hazard Concerns for PFAS
According to EPA, some PFAS are known to persist in the environment because they are resistant to degradation and have been shown to bioaccumulate in wildlife and humans. There are also concerns that some PFAS may cause adverse human health effects, including reproductive, developmental, cancer, liver, immune, thyroid, and other effects. Based on their physicochemical properties and measured environmental concentrations, some PFAS are considered to be environmentally persistent chemicals. In general, according to EPA, most PFAS are resistant to environmental degradation due to their strong carbon-fluorine bonds. While PFAS chain length and chemical structure can have implications for environmental fate, PFAS “are typically resistant to biodegradation, photooxidation, direct photolysis, and hydrolysis which is consistent with their persistence in soil and water.” Some PFAS can also degrade or be metabolized to other PFAS such as PFOA or PFOS. PFAS have been detected in air, surface water, groundwater, drinking water, soil, and food. The presence of PFAS in many parts of the world, including the Arctic, indicate that long-range transport is possible.
EPA states that under the TRI, bioaccumulation, to the extent it happens, is part of the hazard concerns and will be considered both in the listing criteria and in considering lower reporting thresholds. Bioconcentration factors (BCF) estimated from an octanol-water partition coefficient (Kow) or measured in aquatic tests, have typically been used to assess bioaccumulation potential. Kow and the associated BCFs are based on the partitioning of organic chemicals into octanol or lipids. For PFAS such as PFOA and PFOS, partitioning appears to be more related to their protein binding properties than to their lipophilicity, however. Since Kow does not provide a reliable estimate of bioaccumulation potential for these chemicals, EPA states that field evidence of bioaccumulation is preferable. Field measured bioaccumulation factors (BAF) and biomagnification factors (BMF) or trophic magnification factors (TMF) are considered more appropriate indicators of the potential for PFAS, such as PFOA and PFOS, to accumulate in fish, other wildlife, and humans. EPA notes that the trophic magnification data for PFOA and PFOS was deemed sufficient to consider them to be bioaccumulative by the Stockholm Convention Persistent Organic Pollutants Review Committee in 2015.
While the toxicity of PFOA and PFOS has been studied extensively, there are less data available for other PFAS. Differences in PFAS chain length and chemical structure can have implications for environmental fate, bioaccumulation, metabolism, and toxicity. As part of EPA’s PFAS Action Plan, EPA is continuing to collect, systematically review, and evaluate available toxicity data for other PFAS that may help determine whether exposure to structurally similar PFAS results in similar toxic effects.
EPA Hazard Assessments and Other Toxicity Data Available for PFAS
To date, EPA has published two assessments of PFAS: (1) Health Effects Support Document for Perfluorooctane Sulfonate (PFOS); and (2) Health Effects Support Document for Perfluorooctanoic Acid (PFOA). According to EPA, these two documents could be used to determine whether PFOA, PFOS, and related chemicals (e.g., their salts) meet the EPCRA Section 313(d)(2) listing criteria. EPA has also developed two new draft PFAS assessments for public comment: (1) Human Health Toxicity Values for Hexafluoropropylene Oxide (HFPO) Dimer Acid and Its Ammonium Salt (CASRN 13252-13-6 and CASRN 62037-80-3) Also Known as “GenX Chemicals”; and (2) Human Health Toxicity Values for Perfluorobutane Sulfonic Acid (CASRN 375-73-5) and Related Compound Potassium Perfluorobutane Sulfonate (PFBS) (CASRN 29420-49-3). Once these documents are issued in final, EPA “expects these assessments will provide a basis for determining whether GenX chemicals and PFBS meet the EPCRA section 313(d)(2) listing criteria.”
In addition, EPA states that it is working on hazard assessments for the following PFAS containing varying degrees of available toxicity information relevant for human health assessment purposes: perfluorononanoic acid (PFNA); perfluorobutanoic acid (PFBA); perfluorodecanoic acid (PFDA); perfluorohexanoic acid (PFHxA); and perfluorohexane sulfonic acid (PFHxS). Once issued in final, EPA expects these assessments will provide a basis for determining whether these chemicals meet the EPCRA Section 313(d)(2) listing criteria.
EPA notes that it has also collected scientific literature on approximately 30 PFAS. For some of these PFAS, EPA notes that there may be epidemiological and/or experimental animal toxicity data available for review and evaluation of suitability to inform potential human health effects.
Lastly, EPA states that it is collaborating with the National Toxicology Program (NTP) to study individual PFAS and PFAS as a chemical class. Specifically, NTP has conducted toxicology studies to evaluate and identify the adverse effects of certain PFAS chemicals, including PFBS, PFHxS, PFOS, PFHxA, PFOA, PFNA, and PFDA. According to EPA, “NTP continues to assess the potential health effects of PFAS through a large multi-faceted research effort.”
EPA notes that it relies on its hazard assessments and externally peer-reviewed hazard assessments from other federal agencies in making determinations as to whether a chemical meets the EPCRA Section 313 listing criteria. EPA will consider all PFAS assessments on the human health and environmental effects of PFAS that are available from all sources, including those being conducted by other federal agencies.
Information Requested by EPA
EPA seeks comments on which of the approximately 600 PFAS currently active in U.S. commerce it should consider evaluating for potential addition to the EPCRA Section 313 list of toxic chemicals. EPA states that it would also like to receive comments on whether there are data available to inform how to list PFAS, i.e., as individual chemical listings, as a single category, as multiple categories, or as a combination of individual listings and category listings. EPA notes that when chemicals are listed as a category, the TRI reports submitted would include combined data for all members of the category, such that there are no data reported specific to any individual member of the category.
EPA also seeks comments on the appropriate reporting thresholds for PFAS. Reporting thresholds should be set at an appropriate level to capture most of the releases of PFAS from the facilities that submit reports under EPCRA Section 313. Finally, EPA states that it would like to receive any additional information on human health and environmental toxicity, persistence, and bioaccumulation of PFAS that would help determine if they meet the EPCRA Section 313 listing criteria.
According to the ANPRM, EPA intends to review carefully all the comments and information received, as well as previously collected and assembled studies. Once EPA completes its review, it may supplement the collected information with additional hazard assessments to determine whether some PFAS meet the EPCRA Section 313(d)(2) criteria. Should EPA decide to move forward with this action, it will publish a proposed rule to add certain PFAS to the EPCRA Section 313 toxic chemical list and set the appropriate reporting thresholds. At that time, the public will have the opportunity to comment on EPA’s proposal.
This ANPRM is one of several recent steps that EPA has taken to address PFAS. EPA announced on December 4, 2019, that it sent a proposed regulatory determination for PFOS and PFOA in drinking water to the Office of Management and Budget (OMB) for review on December 3, 2019. As reported in our October 1, 2019, blog item, on September 25, 2019, EPA submitted a proposed significant new use rule (SNUR) on long-chain perfluoroalkyl carboxylate (LCPFAC) and PFAS chemical substances to OMB for review.
The ANPRM is a precursor step to a rule proposing TRI listing. It will likely be late 2020 or sometime in 2021 before EPA would publish a rule proposal. Meanwhile, Congress is considering legislation in both chambers that would direct TRI listing. The Senate legislation (S.1507) calls for listing approximately a dozen PFAS and the House bill (H.R. 2577) would list all PFAS. Legislative action may occur before EPA’s regulatory process would result in a final rule adding PFAS to the TRI list. Neither bill is likely to pass as stand-alone legislation. The bills are currently part of several PFAS measures attached to the National Defense Authorization Act (NDAA), reauthorizing military spending. The NDAA is the subject of ongoing negotiations and may pass before the close of 2019.