[Federal Register Volume 89, Number 27 (Thursday, February 8, 2024)]
[Proposed Rules]
[Pages 8606-8621]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-02324]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 261 and 271

[EPA-HQ-OLEM-2023-0278; FRL-9248-01-OLEM]
RIN 2050-AH26


Listing of Specific PFAS as Hazardous Constituents

AGENCY: Environmental Protection Agency (EPA)

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA or the Agency) is 
proposing to amend its regulation under the Resource Conservation and 
Recovery Act (RCRA) by adding nine specific per-and polyfluoroalkyl 
substances (PFAS), their salts, and their structural isomers, to its 
list of hazardous constituents. These nine PFAS are perfluorooctanoic 
acid (PFOA), perfluorooctanesulfonic acid (PFOS), 
perfluorobutanesulfonic acid (PFBS), hexafluoropropylene oxide-dimer 
acid (HFPO-DA or GenX), perfluorononanoic acid (PFNA), 
perfluorohexanesulfonic acid (PFHxS), perfluorodecanoic acid (PFDA), 
perfluorohexanoic acid (PFHxA), and perfluorobutanoic acid (PFBA). 
EPA's criteria for listing substances as hazardous constituents under 
RCRA require that they have been shown in scientific studies to have 
toxic, carcinogenic, mutagenic, or teratogenic effects on humans or 
other life forms. EPA reviewed and evaluated key toxicity and 
epidemiological studies and assessments for the nine PFAS to determine 
whether the available data for these PFAS meet the Agency's criteria 
for listing substances as hazardous constituents under RCRA. Based on 
EPA's evaluation, the above nine PFAS, their salts, and their 
structural isomers meet the criteria for being listed as RCRA hazardous 
constituents. As a result of this proposed rule, if finalized, when 
corrective action requirements are imposed at a facility, these PFAS 
would be among the hazardous constituents expressly identified for 
consideration in RCRA facility assessments and, where necessary, 
further investigation and cleanup through the RCRA corrective action 
process at RCRA treatment, storage, and disposal facilities.

DATES: Comments must be received on or before April 8, 2024.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OLEM-2023-0278, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov 
(our preferred method). Follow the online instructions for submitting 
comments.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, OLEM Docket, Mail Code 28221T, 1200 Pennsylvania Avenue NW, 
Washington, DC 20460.
     Hand Delivery or Courier: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operations are 8:30 a.m.-4:30 p.m., 
Monday-Friday (except Federal Holidays).
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the ``Public Participation'' 
heading of the SUPPLEMENTARY INFORMATION section of this document. For 
further information on EPA Docket Center services and the current 
status, please visit us online at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Narendra Chaudhari, Office of Resource 
Conservation and Recovery (5304T), Environmental Protection Agency, 
1200 Pennsylvania Avenue NW, Washington, DC 20460; telephone number 
202-566-0495; email address: [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Public Participation
    A. Written Comments
II. General Information
    A. Does this action apply to me?
    B. What action is the Agency taking?
    C. Why is the Agency taking this action?
    D. Impacts of the Proposed Rule
    E. What are the incremental costs and benefits of this action?
III. Legal Authority
    A. What is the Agency's authority for taking this action?
    B. RCRA Sections 3001 and 3004(u) Preclude Consideration of Cost 
in Identifying Hazardous Constituents
IV. Background
    A. What are PFAS?
    B. What has been learned from PFAS toxicity studies?

[[Page 8607]]

V. Review of the Available Toxicity and Health Effects Information 
for PFAS
    A. PFAS Identified To Have Sufficient Information To Be 
Evaluated for Appendix VIII Listing Criteria
    B. Summary of Toxicity and Health Effects Information for the 
Nine PFAS
    C. EPA's Proposed Conclusions on Whether the Nine PFAS, Their 
Salts, and Their Structural Isomers Meet the Criteria for Listing on 
Appendix VIII
VI. State Authorization
    A. Applicability of the Rule in Authorized States
    B. Effect on State Authorization
VII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 14094: Modernizing Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA)
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations; Executive Order 14096: Revitalizing Our Nation's 
Commitment to Environmental Justice for All
VIII. References

List of Abbreviations and Acronyms

    The following list is for reference only and is not exhaustive:

AFFF Aqueous film-forming foam
ATSDR Agency for Toxic Substances and Disease Registry
CDC Centers for Disease Control and Prevention
CERCLA Comprehensive Environmental Response, Compensation, and 
Liability Act
CFR Code of Federal Regulations
ECF Electrochemical fluorination
EJ Environmental justice
EPA Environmental Protection Agency
FR Federal Register
GenX Processing aid technology that includes Hexafluoropropylene 
Oxide-Dimer acid and its ammonium salt
HFPO-DA Hexafluoropropylene Oxide-Dimer acid
HSWA Hazardous and Solid Waste Amendments of 1984
mg/kg milligram per kilogram
mg/kg/day milligram per kilogram per day
NAICS North American Industrial Classification System
OMB Office of Management and Budget
PBI Proprietary Business Information
PFAS Per- and polyfluoroalkyl substances
PFBA Perfluorobutanoic acid
PFBS Perfluorobutanesulfonic acid
PFDA Perfluorodecanoic acid
PFHxA Perfluorohexanoic acid
PFHxS Perfluorohexanesulfonic acid
PFNA Perfluorononanoic acid
PFOA Perfluorooctanoic acid
PFOS Perfluorooctanesulfonic acid
RCRA Resource Conservation and Recovery Act
RFA Regulatory Flexibility Act
RfD Reference dose
SWMU Solid Waste Management Unit
TSDFs Treatment, storage, and disposal facilities
UMRA Unfunded Mandates Reform Act
U.S. United States
U.S.C. United States Code

I. Public Participation

A. Written Comments

    Submit your comments, identified by Docket ID No. EPA-HQ-OLEM-2023-
0278, at https://www.regulations.gov (our preferred method), or the 
other methods identified in the ADDRESSES section. Once submitted, 
comments cannot be edited or removed from the docket. EPA may publish 
any comment received to its public docket. Do not submit to EPA's 
docket at https://www.regulations.gov any information you consider to 
be Proprietary Business Information (PBI) or other information whose 
disclosure is restricted by statute. Multimedia submissions (audio, 
video, etc.) must be accompanied by a written comment. The written 
comment is considered the official comment and should include 
discussion of all points you wish to make. EPA will generally not 
consider comments or comment contents located outside of the primary 
submission (i.e., on the web, cloud, or other file sharing system). For 
additional submission methods, the full EPA public comment policy, 
information about PBI or multimedia submissions, and general guidance 
on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    For further information and updates on EPA Docket Center services, 
please visit us online at https://www.epa.gov/dockets.
    EPA continues to monitor information carefully and continuously 
from the Centers for Disease Control and Prevention (CDC), local area 
health departments, and our Federal partners so that we can respond 
rapidly as conditions change regarding COVID-19.

II. General Information

A. Does this action apply to me?

    The purpose of this proposed rulemaking is to add nine PFAS, their 
salts, and their structural isomers, to the list of hazardous 
constituents in 40 CFR part 261 Appendix VIII (Appendix VIII). Entities 
potentially affected by this action include hazardous waste treatment, 
storage, and disposal facilities (TSDFs) with solid waste management 
units (SWMUs) that have released or could release any of the PFAS 
proposed to be listed as RCRA hazardous constituents. EPA has 
identified 1,740 such facilities, which could be subject to additional 
corrective action requirements (pursuant to RCRA section 3004(u) and 
(v)) to address releases not already subject to corrective action 
pursuant to EPA's corrective action regulations.
    The following list of North American Industrial Classification 
System (NAICS) codes is not intended to be exhaustive, but rather 
provides a guide for readers to determine whether this action may 
affect them. For further details about the potentially affected 
universe of facilities, refer to Section 3.2 of the draft Economic 
Assessment of the Potential Costs, Benefits, and Other Impacts of the 
Proposed Rulemaking to List Specific PFAS as RCRA Hazardous 
Constituents (Ref. 41), which can be found in the public docket for 
this action. Potentially affected entities may include:

                Table II-1--Potentially Affected Entities
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                                                            Facilities
                                            Universe of     with higher
 NAICS (3-digits)    NAICS description      facilities     likelihood of
                                                           handling PFAS
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111..............  Crop Production......               2  ..............
115..............  Support Activities                  1  ..............
                    for Agriculture and
                    Forestry.
211..............  Oil and Gas                         2               1
                    Extraction.
213..............  Support Activities                  2  ..............
                    for Mining.

[[Page 8608]]

 
221..............  Utilities............              25               1
233..............  Building, Developing,               1  ..............
                    and General
                    Contracting.
238..............  Specialty Trade                     2  ..............
                    Contractors.
311..............  Food Manufacturing...               3  ..............
312..............  Beverage and Tobacco                1  ..............
                    Product
                    Manufacturing.
313..............  Textile Mills........               4               4
321..............  Wood Product                       52  ..............
                    Manufacturing.
322..............  Paper Manufacturing..               3               1
323..............  Printing and Related                1  ..............
                    Support Activities.
324..............  Petroleum and Coal                 79              76
                    Products
                    Manufacturing.
325..............  Chemical                          335             278
                    Manufacturing.
326..............  Plastics and Rubber                14               9
                    Products
                    Manufacturing.
327..............  Nonmetallic Mineral                23               9
                    Product
                    Manufacturing.
331..............  Primary Metal                      68               1
                    Manufacturing.
332..............  Fabricated Metal                   68              28
                    Product
                    Manufacturing.
333..............  Machinery                          20  ..............
                    Manufacturing.
334..............  Computer and                       46              19
                    Electronic Product
                    Manufacturing.
335..............  Electrical Equipment,              12               3
                    Appliance, and
                    Component
                    Manufacturing.
336..............  Transportation                     64  ..............
                    Equipment
                    Manufacturing.
337..............  Furniture and Related               1  ..............
                    Product
                    Manufacturing.
339..............  Miscellaneous                      14               2
                    Manufacturing.
422..............  Wholesale Trade,                    6  ..............
                    Nondurable Goods.
423..............  Merchant Wholesalers,              14  ..............
                    Durable Goods.
424..............  Merchant Wholesalers,              38              38
                    Nondurable Goods.
447..............  Gasoline Stations....               1  ..............
454..............  Non-store Retailers..               1  ..............
481..............  Air Transportation...               3  ..............
482..............  Rail Transportation..               4  ..............
484..............  Truck Transportation.               2  ..............
486..............  Pipeline                            4  ..............
                    Transportation.
488..............  Support Activities                 11               1
                    for Transportation.
493..............  Warehousing and                    22  ..............
                    Storage.
519..............  Other Information                   1  ..............
                    Services.
525..............  Funds, Trusts, and                  3  ..............
                    Other Financial
                    Vehicles.
531..............  Real Estate..........              12  ..............
532..............  Rental and Leasing                  4  ..............
                    Services.
541..............  Professional,                      39  ..............
                    Scientific, and
                    Technical Services.
551..............  Management of                       2  ..............
                    Companies and
                    Enterprises.
561..............  Administrative and                 22  ..............
                    Support Services.
562..............  Waste Management and              461             359
                    Remediation Services.
611..............  Educational Services.              31  ..............
621..............  Ambulatory Health                   2  ..............
                    Care Services.
622..............  Hospitals............               3  ..............
811..............  Repair and                          7  ..............
                    Maintenance.
813..............  Religious,                          2  ..............
                    Grantmaking, Civic,
                    Professional, and
                    Similar
                    Organizations.
921..............  Executive,                         13  ..............
                    Legislative, and
                    Other General
                    Government Support.
922..............  Justice, Public                     2  ..............
                    Order, and Safety
                    Activities.
924..............  Administration of                   9  ..............
                    Environmental
                    Quality Programs.
925..............  Administration of                   1  ..............
                    Housing Programs,
                    Urban Planning, and
                    Community
                    Development.
926..............  Administration of                   3  ..............
                    Economic Programs.
927..............  Space Research and                  5  ..............
                    Technology.
928..............  National Security and             142               1
                    International
                    Affairs.
Missing..........  .....................              27  ..............
                                         -------------------------------
    Total........  .....................           1,740             831
------------------------------------------------------------------------
Notes: 1. This proposed rule only lists specific PFAS as hazardous
  constituents in 40 CFR part 261, Appendix VIII. EPA notes that listing
  these PFAS as RCRA hazardous constituents does not make them, or the
  wastes containing them, RCRA hazardous wastes.


[[Page 8609]]

B. What action is the Agency taking?

    This action is proposing to amend EPA's regulations under RCRA by 
listing the following nine PFAS (names given for acid forms below), 
their salts, and their structural isomers \1\ as hazardous constituents 
in 40 CFR part 261 Appendix VIII:
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    \1\ All references to PFOA, PFOS, PFBS, HFPO-DA (or GenX), PFNA, 
PFHxS, PFDA, PFHxA, and PFBA or to all nine PFAS in this notice are 
meant to include their salts and their linear and branched 
structural isomers, except where the notice expressly distinguishes 
the different forms. The CASRN for the linear acid version is given 
for reference. Linear and branched structural isomers maintain the 
carboxylic acid and sulfonic acid functional groups, respectively, 
but have different arrangements of the carbon atoms in the 
fluorinated carbon chain. The reference to HFPO-DA only applies to 
the specific structural isomer noted, including both enantiomers.

    1. Perfluorooctanoic acid (PFOA; CASRN 335-67-1). PFOA is an 
eight-carbon molecule with seven fully fluorinated carbon atoms and 
one carboxylic acid functional group. It has been used as a 
processing aid to produce fluoropolymers and has been found in 
cleaning agents, waxes, aqueous film-forming foam (AFFF), and other 
products.
    2. Perfluorooctanesulfonic acid (PFOS; CASRN 1763-23-1). PFOS is 
a fully fluorinated eight-carbon molecule with one sulfonic acid 
functional group. It has been used in AFFF, in surface treatments of 
textiles to provide oil and water resistance, in metal plating, and 
other uses and industries.
    3. Perfluorobutanesulfonic acid (PFBS; CASRN 375-73-5). PFBS is 
a fully fluorinated four-carbon molecule with one sulfonic acid 
group. It has been used as a replacement for PFOS and has been used 
in the manufacture of paints and cleaning agents, metal plating, 
AFFF, to provide oil and water resistance, and other uses and 
industries.
    4. Hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX; CASRN 
13252-13-6). HFPO-DA is a six-carbon molecule consisting of five 
fully fluorinated carbon atoms, one ether functional group, and one 
carboxylic acid functional group. HFPO-DA is a chemical associated 
with GenX processing aid technology used to make fluoropolymers 
without the use of PFOA.
    5. Perfluorononanoic acid (PFNA; CASRN 375-95-1). PFNA is a 
nine-carbon molecule with eight fully fluorinated carbon atoms and 
one carboxylic acid functional group. It has been used as a 
processing aid to produce fluoropolymers and has been used or found 
in metal plating, cleaning agents, waxes, AFFF, energetic materials, 
and other products.
    6. Perfluorohexanesulfonic acid (PFHxS; CASRN 355-46-4). PFHxS 
is a fully fluorinated six-carbon molecule with one sulfonic acid 
functional group. It has been used in AFFF, in surface treatments of 
textiles to provide oil and water resistance, in metal plating, and 
other uses and industries.
    7. Perfluorodecanoic acid (PFDA; CASRN 335-76-2). PFDA is a ten-
carbon molecule with nine fully fluorinated carbon atoms and a 
carboxylic acid functional group. It has been used as a processing 
aid to produce fluoropolymers and has been used or found in metal 
plating solutions, cleaning agents, waxes, AFFF, and other products.
    8. Perfluorohexanoic acid (PFHxA; CASRN 307-24-4). PFHxA is a 
six-carbon molecule with five fully fluorinated carbon atoms and a 
carboxylic acid functional group. It has been used or found in metal 
plating solutions, cleaning agents, waxes, AFFF, and other products.
    9. Perfluorobutanoic acid (PFBA; CASRN 375-22-4). PFBA is a 
four-carbon molecule with three fully fluorinated carbon atoms and 
one carboxylic acid functional group. It has been used or found in 
metal plating, cleaning agents, waxes, AFFF, energetic materials, 
and other products.

    In addition, if finalized, this action would add this listing 
action, as it would apply for corrective action purposes, to Table 1 in 
40 CFR 271.1. Table 1 in 40 CFR 271.1 identifies the Federal program 
requirements that are promulgated pursuant to HSWA and take effect in 
all States, regardless of their authorization status.

C. Why is the Agency taking this action?

    EPA is proposing to list the nine PFAS, their salts, and their 
structural isomers as RCRA hazardous constituents because animal and 
epidemiological studies and assessments have shown that exposure to 
these PFAS have toxic and adverse effects in animals, humans, or both. 
The toxic and adverse effects include reproductive effects, 
developmental effects, increased risk of some cancers, reduced immune 
system response, and increased cholesterol levels (Refs. 1 and 2).
    In addition, EPA has received three petitions requesting that the 
Agency take regulatory actions on PFAS under RCRA. The petitions were 
submitted by Public Employees for Environmental Responsibility (PEER), 
Environmental Law Clinic of University of California, Berkeley (UC 
Berkeley), and the Governor of New Mexico. PEER's petition, submitted 
on September 19, 2019, requested that EPA develop regulations for 
listing wastes containing PFAS (long-chain and short chain) as 
hazardous wastes under Subtitle C of RCRA to ensure the safe management 
and disposal of these wastes (Ref. 3). UC Berkeley's petition, 
submitted on January 15, 2020, on behalf of six community and 
environmental advocacy groups from six different states (California, 
Alaska, North Carolina, Pennsylvania, Michigan, and Colorado), 
requested that EPA promulgate regulations listing wastes containing 
PFOA, PFOS, GenX chemicals (including HFPO-DA and its ammonium salt), 
or any combination of these, as hazardous wastes and that the RCRA 
hazardous waste listings for PFOA and PFOS wastes extend to cover the 
full chemical subclass of each (long-chain perfluoroalkyl carboxylates 
and sulfonates) (Ref. 4). The Governor of New Mexico's petition, 
submitted on June 23, 2021, incorporated the above two petitions by 
reference and requested a timely listing of PFAS, as a class of 
chemicals, as hazardous wastes under the RCRA Subtitle C regulations, 
or in the alternative, a listing of individual PFAS chemicals as 
hazardous wastes under the regulations (Ref. 5). EPA acted upon the 
Governor of New Mexico's petition with its October 26, 2021 letter 
(Ref. 6). EPA indicated in that letter that it would be initiating the 
rulemaking process for two rulemakings. This proposal, along with EPA's 
proposal titled Definition of Hazardous Waste Applicable to Corrective 
Action for Releases from Solid Waste Management Units, constitute 
initiation of those rulemakings.
    EPA evaluated the information in the above three petitions in 
addition to the toxicity and health effects data available for PFAS and 
determined that the existing data for PFAS supports listing the nine 
PFAS, their salts, and their structural isomers at issue in this action 
as RCRA hazardous constituents in 40 CFR part 261 Appendix VIII (see 
section V for additional information).
    A hazardous constituent listing is a step toward a potential 
hazardous waste listing. To list a waste as a RCRA hazardous waste 
under 40 CFR 261.11(a)(3), the Agency must show that the waste contains 
a hazardous constituent listed on Appendix VIII and determine that it 
is capable of posing a substantial hazard. This determination requires 
EPA to collect and carefully consider information on the eleven 
regulatory factors specified in 40 CFR 261.11(a)(3).\2\ If finalized, 
this hazardous constituent listing would form part of the basis for any 
future action the Agency may take to list these substances as a 
hazardous waste. EPA will continue to evaluate available data to 
determine whether a future regulatory action to list certain PFAS, or 
waste containing such PFAS, as regulatory hazardous waste is 
appropriate. In the meantime, based on the toxicity and human health 
effects data available and

[[Page 8610]]

evaluated by EPA for each of the nine PFAS, EPA is moving forward with 
this regulatory action under RCRA to add the nine PFAS, their salts, 
and their structural isomers, as hazardous constituents in 40 CFR part 
261 Appendix VIII.
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    \2\ The eleven factors to be considered are: constituent 
toxicity, concentration, migration potential, persistence, 
degradation product potential, bioaccumulation potential, plausible 
management scenarios, waste quantity, damage cases, coverage by 
other regulatory programs, and other factors as may be appropriate.
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    Finally, EPA is proposing to designate these PFAS as hazardous 
constituents so that when corrective action requirements are imposed by 
program implementers these PFAS would be among the constituents 
expressly identified for consideration in RCRA facility assessments, 
and where necessary, further investigation and cleanup through the RCRA 
corrective action process at RCRA TSDFs.

D. Impacts of the Proposed Rule

    EPA is proposing to list nine PFAS, their salts, and their 
structural isomers, as RCRA hazardous constituents in 40 CFR part 261 
Appendix VIII. The Appendix VIII list of hazardous constituents does 
not by itself impose regulatory requirements. Rather, references to 
hazardous constituents are found in various sections of the Federal 
hazardous waste regulations in Parts 261, 264, 265, 268, and 270.
    The principal impacts of this rule will be on the RCRA Corrective 
Action Program. EPA expects that the proposed rule, combined with the 
Agency's increased attention to addressing risks associated with 
PFAS,\3\ would facilitate and likely result in additional corrective 
action to address releases of specific PFAS listed as RCRA hazardous 
constituents. RCRA section 3004(u) requires that any permit issued to a 
TSDF after November 8, 1984 require corrective action for all releases 
of hazardous waste or hazardous constituents from solid waste 
management units at the facility. In the 1990 Subpart S proposed 
corrective action rule (see 55 FR 30798; July 27, 1990), EPA stated its 
view that the use of the phrase ``hazardous waste or constituents'' in 
section 3004(u) indicates that Congress was particularly concerned that 
the Agency use its corrective action authority to address hazardous 
constituents and stated that the term ``hazardous constituents'' in 
section 3004(u) means those constituents found in Appendix VIII.\4\ 
Thus, hazardous constituents listed on Appendix VIII are assessed for 
and addressed as part of the corrective action process as necessary to 
protect human health and the environment. As a result of this proposed 
rule, nine PFAS, their salts, and their structural isomers would be 
among the hazardous constituents expressly identified for consideration 
in RCRA facility assessments and, where necessary, further 
investigation and cleanup through the corrective action process.\5\ 
Additional discussion of this topic can be found in the draft Economic 
Assessment (Ref. 41). Applicability of the rule in authorized states 
and effect on state authorization are discussed in Section VI of this 
preamble.
---------------------------------------------------------------------------

    \3\ For example, see, PFAS Strategic Roadmap, EPA's Commitment 
to Action 2021-2024, https://www.epa.gov/system/files/documents/2021-10/pfas-roadmap_final-508.pdf.
    \4\ EPA, in addition, proposed to include constituents appearing 
in 40 CFR part 264 Appendix IX as hazardous constituents subject to 
corrective action. 55 FR at 30809.
    \5\ A facility-specific administrative record would still be 
needed to support corrective action measures imposed on the basis of 
protection of human health or the environment.
---------------------------------------------------------------------------

    While various RCRA regulatory provisions, unrelated to corrective 
action, reference hazardous constituents, EPA expects that any impacts 
from those references would be negligible, as EPA expects that the 
processes and procedures currently in place to meet the requirements of 
these regulations would likely address PFAS as well as other 
constituents already on Appendix VIII. Furthermore, there are also a 
few references to hazardous constituents or Appendix VIII in other, 
non-RCRA, EPA regulations; EPA also believes the impacts from these 
regulations would be negligible.
    The scope of this proposal is limited. Listing these PFAS as RCRA 
hazardous constituents does not make them, or the wastes containing 
them, RCRA hazardous wastes. Additionally, only facilities that are 
hazardous waste TSDFs are subject to RCRA corrective action. 42 U.S.C. 
3004(u), (v). Therefore, EPA anticipates that, for example, a facility 
such as a publicly owned treatment works (POTW), would not be 
potentially affected by the RCRA corrective action requirements unless 
the facility is a hazardous waste TSDF. Finally, the domestic sewage 
exclusion in 40 CFR 261.4(a)(1), which excludes domestic sewage and any 
mixture of domestic sewage and other wastes that passes through a sewer 
system from being considered solid wastes (with some exceptions), 
applies to the POTW influent.
    Similarly, solid waste disposal facilities, such as municipal 
waste, or construction and demolition landfills would not be 
potentially affected by the RCRA corrective action requirements unless 
such facilities also operate as hazardous waste TSDFs.
    EPA solicits comment on the impacts of this rule on the RCRA 
Corrective Action Program and the interaction with other existing RCRA 
regulatory provisions including those non-corrective action provisions 
that reference hazardous constituents.

E. What are the incremental costs and benefits of this action?

    EPA has evaluated the potential impacts and associated costs and 
benefits of this proposed rule. The draft Economic Assessment (EA) for 
this action, Economic Assessment of the Potential Costs, Benefits, and 
Other Impacts of the Proposed Rulemaking to List Specific PFAS as RCRA 
Hazardous Constituents (Ref. 41), is available in the docket for this 
action. If finalized, the quantifiable direct annual social cost of 
this proposed rule is estimated to be negligible, as EPA anticipates no 
significant direct impacts (see Sections II.A. and II.D. of this 
preamble).
    However, listing the specific PFAS as RCRA hazardous constituents 
may have indirect, indeterminate impacts associated with potential 
increases in the speed, extent, and total number of corrective action 
activities at certain TSDFs to address PFAS releases. Such potential 
increases are dependent upon subsequent actions and numerous factors, 
including decisions made and implemented by the permitting authority 
regarding associated corrective actions at certain TSDFs.
    RCRA Corrective Action Program implementers already have authority 
to require investigation and cleanup at RCRA TSDFs for substances not 
identified as hazardous constituents either through state cleanup 
regulations, or through the authority provided by section 270.32(b)(2), 
EPA's omnibus authority, and authorized state analogues. In addition, 
cleanup at TSDFs can also be required or conducted pursuant to CERCLA, 
such as ongoing DOD PFAS investigations and responses under CERCLA. EPA 
has also proposed to designate certain PFAS as CERCLA hazardous 
substances (see 87 FR 54415; September 6, 2022). It is uncertain how 
many investigative and response actions for releases of these nine 
PFAS, and their salts, and structural isomers, would occur under the 
authority of this rule that would not have occurred absent this rule 
under one of these other authorities.
    While there are significant uncertainties about potential indirect 
impacts and the precise costs and benefits associated with corrective 
action are nonquantifiable due to these significant uncertainties, EPA 
provides hypothetical scenarios for how corrective action activity 
costs may increase for certain TSDFs as a result of

[[Page 8611]]

addressing PFAS contamination. EPA also considers potential indirect 
benefits associated with corrective action, including avoided risk 
exposures, improved waste management practices, and improved quality of 
information about PFAS cleanup efforts. Other indirect effects may be 
experienced as a result of hastened investigative and cleanup 
activities that would otherwise be implemented pursuant to RCRA or 
other authorities which are not predicated upon a hazardous constituent 
determination. The full discussion of direct and indirect impacts is 
presented in the EA, which can be found in the public docket. EPA 
requests comment on specific aspects of the EA; see EA sections 
4.3.3.1, 4.3.3.2, and 5.3.4.5. EPA also solicits comment on whether the 
potential impacts of this rulemaking may be affected by the 
availability of other authorities that program implementers might rely 
on to satisfy corrective action requirements to address PFAS at RCRA 
facilities including other RCRA authorities such as omnibus permitting 
authority and RCRA section 7003, and CERCLA.

III. Legal Authority

A. What is the Agency's authority for taking this action?

    EPA is proposing these regulations under the authority of sections 
2002(a), 3001, and 3004 of the Solid Waste Disposal Act of 1965, as 
amended by the Resource Conservation and Recovery Act of 1976 (RCRA), 
as amended, by the Hazardous and Solid Waste Amendments of 1984 (HSWA), 
among other amendments, 42 U.S.C. 6912(a), 6921, and 6924. These public 
laws combined are commonly referred to as the ``Resource Conservation 
and Recovery Act'' (RCRA) and will be referred to as such for the 
remainder of this notice.
    RCRA was enacted to effectively manage hazardous and solid wastes 
and thereby protect human health and the environment. RCRA 2002(a) 
provides EPA the general authority to prescribe regulations to carry 
out the functions of RCRA. RCRA section 3001 provides EPA with the 
authority to promulgate criteria for identifying and listing hazardous 
waste, and to identify and list hazardous wastes based on those 
criteria.\6\ On May 19, 1980, EPA promulgated the initial list of 
hazardous constituents under this authority, which serve as part of the 
criteria for listing hazardous wastes,\7\ 40 CFR part 261, Appendix 
VIII. EPA has amended Appendix VIII several times to list or delete 
hazardous constituents. The criteria for listing substances as RCRA 
hazardous constituents on Appendix VIII are specified under 40 CFR 
261.11(a)(3). The criteria state that substances will be listed on 
Appendix VIII ``only if they have been shown in scientific studies to 
have toxic, carcinogenic, mutagenic or teratogenic effects on humans or 
other life forms.''
---------------------------------------------------------------------------

    \6\ RCRA section 3001(a) and (b), 42 U.S.C. 6921(a), (b).
    \7\ Hazardous Waste Management System: Identification and 
Listing of Hazardous Waste, 45 FR 33084, May 19, 1980.
---------------------------------------------------------------------------

    The 1984 Hazardous and Solid Waste Amendments (HSWA) to RCRA 
expanded EPA's authority to address releases of hazardous waste and 
constituents at RCRA treatment, storage, and disposal facilities. This 
includes section 3004(u) and (v) of RCRA, which provides for corrective 
action requirements at permitted facilities. Section 3004(u) authorizes 
EPA to promulgate standards requiring corrective action for all 
releases of hazardous waste and hazardous constituents from solid waste 
management units at permitted hazardous waste treatment, storage, or 
disposal facilities regardless of the time at which waste was placed in 
the units.\8\ Section 3004(u) further mandates that permits require 
financial assurance for completion of corrective action.
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    \8\ Section 3004(u) provides that ``standards promulgated under 
this section shall require, and a permit issued . . . by the 
Administrator or a State shall require, corrective action for all 
releases of hazardous waste or constituents from any solid waste 
management unit . . . regardless of the time at which waste was 
placed in such unit.''
---------------------------------------------------------------------------

    Section 3004(v) directed EPA to require that corrective action be 
taken beyond facility boundaries where necessary to protect human 
health and the environment unless facility owners/operators demonstrate 
to the Agency's satisfaction that, despite their best efforts, they 
were unable to obtain the necessary permission to undertake off-site 
corrective action. 40 CFR 264.101 essentially codifies these RCRA 
section 3004(u) and (v) requirements. EPA has interpreted the hazardous 
constituents subject to corrective action as including those 
constituents identified in 40 CFR part 261 Appendix VIII and 40 CFR 
part 264 Appendix IX, 55 FR 30798, 30809 (July 27, 1990).
    A significant part of EPA's objective in proposing to add the new 
constituents to Appendix VIII is to ensure that releases of those 
substances can be effectively and efficiently considered and addressed 
through corrective action. In addition, the principal regulatory impact 
of this action would be to expand the scope of constituents subject to 
routine consideration in the corrective action process. Therefore, EPA 
is relying on its authority under RCRA section 3004(u) to propose 
listing these PFAS as hazardous constituents for the purposes of 
corrective action.

B. RCRA Sections 3001 and 3004(u) Preclude Consideration of Cost in 
Identifying Hazardous Constituents

    In RCRA section 3001, Congress directed EPA to promulgate criteria 
for identifying the characteristics of hazardous waste and listing 
hazardous waste. Cost has no bearing on whether a material is 
hazardous, under the ordinary meaning of the word. Consistent with this 
ordinary meaning, Congress directed EPA to take into account 
``toxicity, persistence, and degradability in nature, potential for 
accumulation in tissue, and other related factors such as flammability, 
corrosiveness, and other hazardous characteristics.'' RCRA section 
3001(a); see also, RCRA section 3001(b) (``such as identified 
carcinogens, mutagens, or teratogens''). These statutory factors focus 
on various hazardous characteristics. Congress did not list cost as a 
required or permissible factor, and none of the Congressionally-listed 
statutory factors encompass a consideration of costs. This reflects the 
Agency's longstanding position. See, Hazardous Waste Management System: 
Identification and Listing of Hazardous Waste, 45 FR 33084, 33089, May 
19, 1980. Additionally, determining whether something is ``toxic'' or 
has any of the other identified characteristics described in section 
3001 does not naturally lend itself to considerations of cost--that is, 
whether a substance is or is not toxic is determined by examining the 
properties of the substance at issue.
    In carrying out this statutory obligation, EPA has promulgated 
regulatory criteria for adding constituents to Appendix VIII. 
Consistent with the health- and hazard- related factors identified in 
section 3001(a) and (b), these criteria (``toxic, carcinogenic, 
mutagenic or teratogenic effects on humans or other life forms.''), 40 
CFR 261.11(a)(3), do not include cost nor does cost have any bearing or 
relevance on them.
    EPA interprets the RCRA section 3004(u) corrective action standard-
setting authority as authorizing the identification of hazardous 
constituents subject to corrective action. Moreover, Congress 
identified Appendix VIII as the source for the hazardous constituents 
referenced in 3004(u). See

[[Page 8612]]

H.R. REP. 98-198, 98th Cong., 1st Sess., pt. 1 at 60-61 (1983), 
reprinted in 1984 U.S.C.C.A.N. 5576, 5619-20. (``The term `hazardous 
constituent' as used in this provision is intended to mean those 
constituents listed in Appendix VIII of the RCRA regulations.''). As 
discussed above, cost is not a relevant consideration under the 
ordinary meaning of ``hazardous.'' Thus, as under section 3001, cost 
may not be considered in identifying hazardous constituents under 
section 3004(u).
    If finalized, this rule may have indirect, indeterminate costs and 
benefits associated with the speed, extent, and total number of 
corrective action activities at certain TSDFs to address these nine 
PFAS, their salts, and their structural isomers. EPA has presented cost 
and benefit information consistent with Executive Order 12866 in the EA 
for this rule, but these costs and benefits do not form any part of 
EPA's decision to designate these PFAS substances as hazardous 
constituents.

IV. Background

A. What are PFAS?

    Per- and polyfluoroalkyl substances, also known as PFAS, are a 
class of manufactured chemicals that have been widely used in many 
industrial and consumer products since the 1940s, and they are still 
being used today. PFAS have been or are currently being manufactured 
for a variety of different uses, ranging from adhesives, coatings for 
clothes and furniture, fire-fighting foam, and other uses. PFAS have 
been released into the environment during the manufacturing process and 
from various uses in industrial, commercial, and consumer settings.
    PFAS have carbon chains with fluorine atoms attached to the carbons 
potentially linked to functional groups. Because the carbon-fluorine 
bond is the strongest known single carbon bond, these chemicals do not 
degrade readily in the environment (Ref. 7). However, some bigger 
molecules where a portion of the molecule has fluorinated carbons, 
known as precursors, can degrade or transform into other PFAS that are 
known to be toxic and are potentially mobile in the subsurface 
environment. For example, each of the nine PFAS that are the subject of 
this proposed rulemaking could be present as a result of degradation of 
a precursor. This proposed rulemaking applies to the PFAS identified in 
this action regardless of whether they exist as chemical substances on 
their own or result from degradation of precursors. There are thousands 
of different PFAS (https://comptox.epa.gov/dashboard/chemical-lists/PFASMASTER), some of which have been more widely used and studied than 
others. A growing body of scientific evidence shows that exposure to 
certain PFAS can adversely impact human health and other living things.

B. What has been learned from PFAS toxicity studies?

    Certain PFAS, such as perfluorinated alkyl acids (e.g., PFOA, 
PFOS), are manufactured in both acid and salt forms. In aqueous 
environments, such as groundwater or the digestive system of humans and 
other animals, the acids and salts will dissociate into the ion form. 
Exposure to the salts or acid form of certain PFAS have been shown to 
lead to similar toxicity, as it has often been the salt form used in 
experimental animal toxicity studies.
    PFAS may also be present in products and in the environment as 
mixtures of linear and branched isomers, depending on the methods by 
which they are manufactured. Most studies do not clearly state what 
isomers were used, but of those that do, a mixture of linear and 
branched isomers was generally used. Studies generally only state the 
material purity, but purity does not refer to isomeric mixture. As a 
result, it's not currently practicable to differentiate the toxicity of 
the individual isomers, including the linear isomer. Therefore, any 
reference in this proposal to toxicity and health effects or listing of 
the nine PFAS as hazardous constituents on Appendix VIII includes the 
acids, salts, and structural isomers of the nine PFAS.

V. Review of the Available Toxicity and Health Effects Information for 
PFAS

A. PFAS Identified To Have Sufficient Information To Be Evaluated for 
Appendix VIII Listing Criteria

    EPA's evaluation of the available toxicity and health effects 
information for PFAS focused on PFAS that have final peer reviewed 
assessments and those with toxicity studies supporting ongoing 
assessments. The toxicity and health effects assessments that EPA is 
relying on for this proposal are those published by EPA and the Agency 
for Toxic Substances and Disease Registry (ATSDR).
    The EPA published a final peer reviewed toxicity and health effects 
assessment for PFOA and PFOS in 2016 (Ref. 9 and 14). Updated, draft 
toxicity and health effects assessments for PFOA and PFOS were 
published in 2023 as part of EPA's proposed National Primary Drinking 
Water Regulation for specific PFAS (Ref. 10 and 11). In 2021, EPA 
published a final peer reviewed toxicity and health effects assessment 
for PFBS (Ref. 15) and for HFPO-DA (Ref. 16). EPA published final peer 
reviewed toxicity and health effects assessments for PFBA in 2022 (Ref. 
17) and PFHxA in 2023 (Ref. 32). EPA published a draft toxicity and 
health effects assessment for PFDA in 2023 and sought public comment 
and external peer review (Ref. 31), the final peer review report has 
been published (Ref. 45). EPA's ongoing toxicity and health effects 
assessment process for PFDA is expected to be finalized in the near 
future. EPA also released a draft toxicity and health effects 
assessment for PFHxS in 2023 and sought public comment and external 
peer review (Ref. 44). EPA's ongoing toxicity and health effects 
assessment for PFNA is in progress. ATSDR, in their 2021 Toxicological 
Profile for Perfluoroalkyls, reviewed toxicity information for twelve 
PFAS including PFOA, PFOS, PFBS, PFBA, PFHxA, PFNA, PFDA, and PFHxS 
(Ref. 18). In this Profile ATSDR derived toxicity values for PFOA, 
PFOS, PFNA, and PFHxS.
    Assessments conducted by EPA, ATSDR, and information published in 
scientific studies support the conclusion that PFOA, PFOS, PFBS, HFPO-
DA, PFBA, PFNA, PFHxS, PFDA, and PFHxA warrant a hazardous constituent 
designation.
    It should be noted that EPA's criteria for listing a substance as a 
hazardous constituent on Appendix VIII under 40 CFR 261.11(a)(3) do not 
require a finalized toxicity assessment, or exhaustive search and 
evaluation of all published scientific studies for the substance, or a 
final toxicity value. Rather, the criteria for listing substances on 
Appendix VIII only require that scientific studies have shown one or 
more of the criteria effects for the substances (i.e., toxic, 
carcinogenic, mutagenic or teratogenic effects).
    The Agency's evaluation has determined that more than the required 
scientific information showing toxic, carcinogenic, mutagenic or 
teratogenic effects already exists to list the selected PFAS as RCRA 
hazardous constituents.

B. Summary of Toxicity and Health Effects Information for the Nine PFAS

    Below are brief summaries of the toxicity and adverse health 
effects information for the nine PFAS from the final peer reviewed 
assessments or toxicity studies supporting ongoing assessments. Please 
see the list of references and docket for this proposed rule to 
completely examine these assessments and studies which form the basis 
of EPA's proposed conclusions that these PFAS, their salts, and their

[[Page 8613]]

structural isomers meet the criteria for listing as RCRA hazardous 
constituents.
    Interpreting epidemiology data for PFAS and determining the 
individual toxicological responses of each PFAS individually (or their 
interaction effects) is an ongoing challenge because multiple PFAS have 
been shown to induce similar adverse health effects (e.g., immune, 
developmental, hepatic, cardiovascular effects, cancer). This is a 
subject where the science is rapidly evolving.
1. PFOA
    Human epidemiology data report associations between PFOA exposure 
and high cholesterol, increased liver enzymes and serum lipid levels, 
decreased vaccination response, thyroid disorders, pregnancy-induced 
hypertension and preeclampsia, cancer (testicular and kidney), and 
decreases in birth weight (Refs. 9 and 18).
    Oral animal studies of short-term subchronic and chronic duration 
are available in multiple species including monkeys, rats, and mice. 
These studies report developmental effects, liver toxicity including 
degenerative and necrotic effects, kidney toxicity, immune effects 
including impaired response to antigens, and cancer (liver, testicular, 
and pancreatic). Developmental effects observed in animals include 
decreased survival, delayed eye opening and reduced ossification, 
skeletal defects, altered puberty (delayed vaginal opening in females 
and accelerated puberty in males), and altered mammary gland 
development (Refs. 9 and 18).
    There has been consistent evidence of associations between PFOA 
exposure and immunosuppression including reduced response to vaccines. 
Epidemiology studies have looked at the effects of exposure to several 
PFAS. In one study (Ref. 22), large datasets have been used to mutually 
adjust for concomitant PFAS exposures. Epidemiological studies have 
associated decreased vaccine response in children with elevated levels 
of PFOA in sera (Refs. 19, 20, 21, 22 and 40). Epidemiological studies 
have also indicated an increased risk of renal cell carcinoma with PFOA 
exposure (Refs. 42 and 43). An association with increased risk of 
ulcerative colitis has also been observed. The results of several mouse 
studies reported findings consistent with the epidemiological data 
suggesting that exposure to PFOA can result in immunosuppression (Ref. 
18).\9\
---------------------------------------------------------------------------

    \9\ It is important to note that in March 2023, EPA proposed a 
National Primary Drinking Water Regulation for certain PFAS, 
including PFOA and PFOS (88 FR 18638; March 29, 2023). To support 
this rule, EPA developed and released updated draft toxicity 
assessments for PFOA and PFOS for public comment, to which EPA is 
currently responding (Refs. 10 and 11). The draft toxicity 
assessments underwent external peer review through EPA's Science 
Advisory Board PFAS Review Panel (Ref. 12), and EPA responded to the 
SAB's recommendations in the updated draft toxicity assessments 
(Ref. 13).
---------------------------------------------------------------------------

2. PFOS
    Epidemiology data report associations between PFOS exposure and 
high cholesterol, decreased vaccination response, and altered 
reproductive and developmental parameters including low birth weight. 
The strongest associations are related to serum lipids with increased 
total cholesterol and high-density lipoproteins (HDLs), and there are 
also associations with increases in serum enzymes and decreases in 
serum bilirubin (Refs. 14 and 18). There is suggestive epidemiological 
evidence for an association between serum PFOS and pregnancy-induced 
hypertension and/or pre-eclampsia (Ref. 18). Data also suggest a 
correlation between higher PFOS levels and decreases in female 
fecundity and fertility, in addition to decreased body weights in 
offspring, and other measures of postnatal growth (Ref. 14).
    There is consistent evidence of immunotoxicity after PFOS exposure. 
There is evidence of an association between serum PFOS levels and 
decreased antibody responses to vaccines in children (Ref. 18). 
Epidemiology studies have looked at the effects of exposure to several 
PFAS. In one study (Ref. 22), large datasets have been used to mutually 
adjust for concomitant PFAS exposures. Epidemiological studies have 
indicated decreased vaccine response in children associated with 
elevated levels of PFOS in sera (Refs. 19, 20, 21, 22 and 40). Rodent 
studies have also shown immunotoxicity after PFOS exposure (Ref. 18).
    Short-term and chronic exposure studies in animals consistently 
demonstrate increases in liver weight with co-occurring effects that 
include decreased cholesterol, hepatic steatosis, lower body weight, 
and liver histopathology (Ref. 14). Some degenerative and necrotic 
effects that are likely relevant to humans have been observed (Ref. 
18). One and two generation toxicity studies also show decreased pup 
survival and body weights. Additionally, developmental neurotoxicity 
studies show increased motor activity and decreased habituation and 
increased escape latency in the water maze test following in utero and 
lactational exposure to PFOS. Gestational and lactational exposures 
were also associated with higher serum glucose levels and evidence of 
insulin resistance in adult offspring (Ref. 14).
3. PFBS
    Asthma and serum cholesterol levels in humans were found to exhibit 
a statistically significant positive association with PFBS exposure. No 
studies have been identified that evaluate the association between PFBS 
exposure and potential cancer outcomes (Ref. 15).
    The limited number of human studies examining oral PFBS exposure 
does not inform the potential for effects in thyroid, developing 
offspring, or the renal system (Ref. 15). Animal studies of repeated-
dose PFBS exposure have been exclusively via the oral route, used the 
potassium salt of PFBS as the source exposure material, and have 
examined noncancer effects only. The available rat and mouse studies 
support identification of thyroid, developmental, and kidney endpoints 
as potential health effects following repeated exposures in utero and/
or during adulthood. Thyroid effects in exposed adult rats and mice and 
in developing mice were primarily expressed through significant 
decreases in circulating levels of hormones such as thyroxine and 
triiodothyronine. In early developmental life stages in mice (e.g., 
newborn), decreases in thyroid hormones were accompanied by other 
effects indicative of delayed maturation or reproductive development 
(e.g., vaginal patency and eyes opening). Kidney weight and/or 
histopathological alterations (e.g., renal tubular and ductal 
epithelial hyperplasia) were observed in rats following short-term and 
subchronic oral exposures. Many of the kidney effects, however, 
occurred at higher doses than did the thyroid and developmental 
effects.
    Animal studies have also evaluated other health outcomes, such as 
liver effects, reproductive parameters, lipid/lipoprotein homeostasis, 
and effects on the spleen and blood; however, the evidence currently 
available does not support a clear association with PFBS exposure and 
these outcomes (Ref. 15).
4. HFPO-DA (GenX)
    Most of the available data for HFPO-DA and its ammonium salt (also 
known as GenX chemicals) were submitted to EPA by the manufacturer 
(DuPont/Chemours) under the Toxic Substances Control Act (TSCA), as 
required by TSCA reporting requirements (15 U.S.C.

[[Page 8614]]

2607.8(e)) or pursuant to a consent order (Ref. 23).
    Oral toxicity studies for HFPO-DA and its ammonium salt were 
available for acute, short-term, subchronic, and chronic durations of 
exposure in rats and mice. These studies reported liver effects 
(increased relative liver weight, hepatocellular hypertrophy, single 
cell necrosis and apoptosis), kidney effects (increased relative kidney 
weight), immune effects (antibody suppression), developmental effects 
(increased early deliveries and delays in genital development), and 
tumorigenesis (liver and pancreatic tumors) (Ref. 16). Overall, the 
weight of the scientific evidence indicates the liver as a sensitive 
target for toxicity (meaning the liver is most susceptible to the toxic 
effects); however, the available data are inadequate to determine the 
mode of action for these effects.
    EPA's Office of Water followed current EPA risk assessment guidance 
and recommendations to select points of departure from the available 
animal studies for RfD derivation to support risk characterization. EPA 
also conducted literature searches to identify publicly available peer-
reviewed hazard studies on HFPO-DA and its ammonium salt. All 
laboratory animal studies containing dose-response information were 
evaluated for study quality using an approach consistent with the 
Office of Research and Development's Handbook for developing IRIS 
assessments (Ref. 25).
    EPA selected an oral reproductive/developmental toxicity study in 
mice (Ref. 26) showing hepatotoxicity (i.e., cytoplasmic alterations, 
apoptosis, single-cell necrosis, and focal necrosis) as the critical 
study and effect, respectively. Selection of this effect (liver 
toxicity) is supported by the National Toxicology Program Pathology 
Working Group's conclusion that the dose response for the constellation 
of liver lesions observed following oral exposure to HFPO-DA and its 
ammonium salt represents an adverse (rather than adaptive) response. 
The National Toxicology Program Pathology Working Group's Final Report 
on the Pathology Peer Review of Liver Findings is Appendix D of EPA's 
Human Health Toxicity Values for Hexafluoropropylene Oxide (HFPO) Dimer 
Acid and Its Ammonium Salt (CASRN 13252-13-6 and CASRN 62037-80-3, Ref. 
16). Further support for the selection of liver toxicity as a critical 
effect was obtained from additional animal studies showing similar 
hazard outcomes (i.e., increased liver enzyme levels, histopathological 
lesions, and tumors) in both male and female mice and rats following 
various durations and levels of exposure (Ref. 16).
5. PFNA
    The available epidemiological studies suggest associations between 
PFNA and several health outcomes including increases in serum hepatic 
enzymes, particularly alanine aminotransferase (Ref. 18). Numerous 
studies have evaluated the hepatic toxicity of PFNA. The observed 
effects are consistent with effects observed for other perfluoroalkyl 
acids such as PFOA including alterations in serum lipid levels (Ref. 
18). An epidemiological study has also indicated increased risk of 
renal cell carcinoma with exposure to PFNA, especially within African-
Americans (Ref. 43).
    Some studies have found associations between serum PFNA and 
diphtheria and tetanus antibody levels. Grandjean and associates found 
a significant inverse association between diphtheria antibodies levels 
at age 5 and serum PFNA levels at age 5, but not for antibody levels at 
age 13 and PFNA levels at age 7 or 13. Some others also reported an 
inverse association between serum PFNA and diphtheria antibody levels 
in a small study of adults. An inverse association between maternal 
serum PFNA and rubella antibody levels was observed in children (Refs. 
19, 20, 21, 22, and 24). Timmermann et al. found each 1 ng/mL increase 
in serum concentrations of PFNA was associated with decreases of 39% 
(95% CI: -4-64%) in diphtheria antibody concentrations (Ref. 40).
    Animal studies have also shown detrimental health effects. Two 
weeks after a single administration of PFNA in mice, Kielsen et al. 
also observed a number of immunological alterations (Ref. 24). Two 
acute-duration studies have evaluated the reproductive toxicity of PFNA 
in male rats. PFNA exposure resulted in decreases in serum testosterone 
and increases in serum estradiol levels and morphological changes. 
These changes as well as others were suggestive of damage to the 
secretory function of the Sertoli cells. In mice administered PFNA for 
90 days, decreases in sperm motility, viability, and count and 
degenerative changes in the seminiferous tubules were observed. When 
the mice were mated with unexposed females, significant decreases in 
litter size were observed (Ref. 18).
    Three studies were identified that examined the developmental 
toxicity of PFNA in laboratory animals. Full litter resorptions were 
observed in mice administered PFNA, and maternal weight loss was also 
observed. Decreases in postnatal survival were observed. Decreases in 
birth weight were observed in female offspring of rats. Postnatal 
growth was decreased in the offspring of mice, and the decreases in 
body weight persisted in the pups. Reductions in nephron endowment 
(number of functioning nephrons at birth) were observed in male rat 
pups. Delays in eye opening and decrease in pup body weight gain were 
observed in offspring of mice administered PFNA (Ref. 18).
6. PFHxS
    The available epidemiological studies suggest associations between 
PFHxS and several health outcomes including decreased antibody response 
to vaccines in humans and increases in serum lipids, particularly total 
cholesterol and low-density lipoprotein (LDL) cholesterol, in animals 
(Ref. 18). EPA has released a draft assessment for PFHxS for public 
comment (Ref. 44).
    Epidemiology studies have looked at the effects of exposure to 
several PFAS. In one study (Ref. 22), large datasets have been used to 
mutually adjust for concomitant PFAS exposures. Epidemiological studies 
have indicated decreased vaccine response in children associated with 
elevated levels of PFHxS in sera (Refs. 19, 20, 21, 22, and 40). 
Inverse associations were observed between tetanus antibody levels in 
5- and 7-year-old children and PFHxS levels in maternal serum and in 
children at age 5. A study in 3-year-old children found an inverse 
association between maternal PFHxS levels and rubella antibody levels, 
but no association with influenza type B or tetanus antibody levels. In 
adolescents, serum PFHxS levels were also inversely associated with 
rubella antibody titers in a seropositive subcohort (Ref. 18). 
Timmermann et al. found each 1 ng/mL increase in serum concentrations 
of PFHxS was associated with decreases of 78% (95% CI: 25-94%) in 
diphtheria antibody concentrations.
    Centrilobular hepatocellular hypertrophy was observed in rodents. 
Microvascular fatty changes were also observed. In male mice, dietary 
exposure to PFHxS in a western-type diet resulted in decreases in 
plasma triglyceride, total cholesterol, non-HDL cholesterol, and HDL 
cholesterol levels and decreases in the hepatic production of VLDL. 
Increases in liver weight and hepatic triglyceride levels were also 
observed (Ref. 18).
7. PFDA
    PFDA has been associated with cardiovascular disease, immunological

[[Page 8615]]

affects, and developmental affects. In this subsection, limited human 
and then animal evidence for potentially related health end points are 
discussed together for each end point. EPA has released a draft 
assessment for PFDA for public comment (Ref. 31).
    In a study of NHANES participants, Huang et al. (Ref. 27) found an 
increased risk of any type of cardiovascular disease among participants 
with the highest serum PFDA levels when the statistical analyses 
adjusted for serum total protein levels and estimated glomerular 
filtration rate; however, no associations were found for specific types 
of cardiovascular disease. Death in female mice following 
administration of a single lethal dose of PFDA by gavage was associated 
with mural thrombosis of the left ventricle of the heart. Non-lethal 
doses did not cause gross or microscopic alterations in the heart, 
assessed 30 days after dosing, but significantly decreased relative 
heart weight. Significant decrease in mean corpuscular hemoglobin and 
mean corpuscular hemoglobin concentration were observed in rats 
administered PFDA for 28 days (Ref. 18).
    Epidemiology studies have looked at the effects of exposure to 
several PFAS. In one study, large datasets have been used to mutually 
adjust for concomitant PFAS exposures. Epidemiological studies have 
indicated decreased vaccine response in children associated with 
elevated levels of PFDA in sera (Refs. 19, 20, 21, 22, and 40). Inverse 
associations were observed between serum PFDA levels at age 5 and 
tetanus antibody levels at ages 5 and 7 (Ref. 19) and serum PFDA levels 
at age 7 and antibody levels at age 13 (Ref. 20). Similarly, diphtheria 
antibody levels at age 13 were inversely associated with serum PFDA 
levels at age 7 years (Ref. 20). In adults, diphtheria antibody levels 
were inversely associated with serum PFDA levels, but there was no 
association for tetanus antibody levels.
    In case-control studies, associations between asthma diagnosis and 
asthma severity were observed in children; associations with serum 
immunoglobulin E levels, absolute eosinophil counts, and eosinophil 
cationic protein levels were also observed. A case-control study in 
adolescents found significantly higher serum PFDA levels among the 
asthmatic cases (Ref. 18).
    Lind et al. found an inverse association between maternal PFDA 
levels and anogenital distance in human girls, but not in boys (Ref. 
28). An increase in fetal mortality was observed in mice exposed to 
PFDA, and PFDA was also associated with a marked decrease in fetal 
weight/litter, 100% incidence of variations in ossification of the 
braincase, decreases in maternal body weight, and maternal mortality 
(Ref. 18). Decreases in fetal body weight/litter in mice also were 
observed (Ref. 18).
8. PFHxA
    Although some human epidemiological studies have examined possible 
associations between PFHxA exposure and several adverse health 
outcomes, they are sparse and overall insufficient on their own to draw 
conclusions regarding adverse health effects. Based primarily on animal 
studies, certain PFHxA exposure levels have led to hepatic, 
developmental, hematopoietic, and endocrine effects (Refs. 18 and 32).
    In humans, an increased risk of cardiovascular disease (any type) 
was found in NHANES participants with higher serum PFHxA levels. A 
study of 70-year-old adults reported increases in the intima media 
thickness in the common carotid artery that was associated with serum 
PFHxA levels (Ref. 18). Several studies in rats have identified the 
hematological system as a target of PFHxA toxicity. Decreases in red 
blood cell counts, hemoglobin levels, and/or hematocrit levels and 
increases in reticulocyte levels have been observed in rats 
administered PFHxA (Refs. 18 and 32).
    Increases in liver weight, decreases in serum cholesterol levels, 
and centrilobular hepatocellular hypertrophy have been observed in rats 
administered PFHxA. In a chronic-duration study, gavage administration 
of PFHxA for 2 years resulted in increases in the incidence of 
hepatocellular necrosis in female rats. Decreases in triglyceride 
levels were observed in male rats (Ref. 18). Thus, the hepatic findings 
correlated with changes in clinical chemistry and necrosis (Ref. 32).
    Administration of PFHxA resulted in decreases in fetal weight in 
rats (Ref. 30). Similarly, decreases in pup body weight were observed 
in the offspring of rats administered PFHxA for 70 days prior to 
mating, during mating, and throughout gestation and lactation (Refs. 18 
and 30).
9. PFBA
    Although several human epidemiological studies have examined 
possible associations between PFBA exposure and several adverse health 
outcomes, they are sparse and overall insufficient on their own to draw 
conclusions regarding toxic effects. Based primarily on animal studies, 
developmental, thyroid, and liver effects in humans are likely caused 
by PFBA exposure, given sufficient exposure conditions. In human 
studies, increases in the risk of hypertension in men and women, which 
was associated with serum PFBA levels, have been found. Systolic blood 
pressure levels were also associated with serum PFBA levels in men and 
women combined or in men only; no associations were found for diastolic 
blood pressure (Ref. 17).
    Oral doses of PFBA for 90 days resulted in significant reductions 
in red blood cell counts, hemoglobin, and hematocrit, and an increase 
in red blood cell distribution width in male rats. This dose level also 
caused a reduction in mean corpuscular hemoglobin and reduced mean 
corpuscular hemoglobin concentration in male rats. The lower hemoglobin 
and hematocrit observed in males were still detected at the end of a 3-
week recovery period (Ref. 18).
    PFBA intermediate-duration studies have consistently found 
increases in liver weight and histological alterations. Dosing rats 
with PFBA resulted in significant increases in absolute and relative 
liver weight and decreases in serum cholesterol and hepatocellular 
hypertrophy (Ref. 17 and 18).
    Thyroid effects in adult exposed rats were expressed through 
decreases in free and total thyroxine (T4) and increased incidence of 
thyroid follicular hypertrophy and hyperplasia. Developmental effects 
in exposed animals were expressed as the loss of viable offspring 
(total litter resorption), and postnatal delays in postnatal 
developmental milestones: eye opening, vaginal opening, and preputial 
separation (Ref. 17).

C. EPA's Proposed Conclusions on Whether the Nine PFAS, Their Salts, 
and Their Structural Isomers Meet the Criteria for Listing on Appendix 
VIII

    The Agency's proposed conclusions are that the nine PFAS, their 
salts, and their structural isomers meet the criteria for listing as 
RCRA hazardous constituents on Appendix VIII because it has been shown 
through scientific studies referenced above that they have toxic 
effects on humans or other life forms.
    The nine PFAS discussed in this proposed rule can occur in acid 
forms (e.g., perfluorooctanoic acid) and salt forms (e.g., ammonium 
perfluorooctanoate). Salts are deemed to have the same toxicity as the 
commonly referenced acid versions because, once put in water (and 
likewise when in human blood), the acid and salt forms will dissociate 
to the ionic form. Further, toxicity studies on PFAS were

[[Page 8616]]

often performed using the salt form. Thus, EPA is proposing to list 
both acid and salt forms of the nine PFAS on Appendix VIII.
    Additionally, PFAS exist as linear and branched isomers, depending 
on the process used to manufacture them. For example, PFAS when 
manufactured through electrochemical fluorination consist of an 
isomeric mixture that is approximately 70% linear isomers and 30% 
branched isomers. The linear and branched isomers have been found in 
environmental media and in human sera. Most animal toxicity studies 
using isomeric mixtures do not state the ratio of linear and branched 
isomers in the test material, and, therefore, it is not feasible to 
distinguish the toxicity of the individual isomers. However, in a few 
studies, including Lieder et al. (2009) for PFBS, George and Andersen 
(1986) for PFDA, Bijland et al. (2011) for PFHxS, Butenhoff et al. 
(2004), Lau et al. (2006), and Lou et al. (2009) for PFOA, and Ankley 
et al. (2004) for PFOS (Refs. 33-39), the authors stated that the PFAS 
test substance was not 100% linear, and thus any effects indicated in 
these studies can only be associated with the isomeric mixture of 
linear and branched and not specifically with linear isomers or 
branched isomers. Further, Loveless et al. (2006) compared the toxicity 
of linear ammonium PFOA, branched ammonium PFOA, and a mixture of 
linear and branched ammonium PFOA in rodents, and demonstrated that 
both linear and branched isomers exhibit similar types of toxicity 
(Ref. 29). While toxicity studies such as these are not available for 
all PFAS included in this proposal, EPA believes it is both reasonable 
and public health protective, based on the available toxicity data for 
isomeric mixtures, to list the structural isomers. Thus, EPA is 
proposing to also list the structural isomers for the nine PFAS on 
Appendix VIII.

VI. State Authorization

A. Applicability of the Rule in Authorized States

    Under section 3006 of RCRA, 42 U.S.C. 6926, EPA may authorize a 
qualified State to administer and enforce a hazardous waste program 
within the State in lieu of the Federal program, and to issue and 
enforce permits in the State. Following authorization, EPA retains 
enforcement authority under sections 3008, 3013, and 7003 of RCRA, 
although authorized States have primary enforcement responsibility. The 
standards and requirements for State authorization are found at 40 CFR 
part 271.
    Prior to enactment of the Hazardous and Solid Waste Amendments of 
1984 (HSWA), a State with final RCRA authorization administered its 
hazardous waste program entirely in lieu of EPA administering the 
Federal program in that State. The Federal requirements no longer 
applied in the authorized State, and EPA could not issue permits for 
any facilities in that State, since only the State was authorized to 
issue RCRA permits. When new, more stringent Federal requirements were 
promulgated, the State was obligated to enact equivalent authorities 
within specified timeframes. However, the new Federal requirements did 
not take effect in an authorized State until the State adopted the 
Federal requirements.
    In contrast, under RCRA section 3006(g), (42 U.S.C. 6926(g)) (which 
was added by HSWA), new Federal requirements and prohibitions imposed, 
pursuant to HSWA authority, take effect in authorized States at the 
same time that they take effect in unauthorized States. Although 
authorized States are still required to update their hazardous waste 
programs to remain equivalent to the Federal program, EPA is directed 
by the statute to implement the requirements and prohibitions in 
authorized States, including the issuance of new permits implementing 
those new requirements, until EPA authorizes the State to do so.
    Authorized States are required to modify their programs only when 
EPA promulgates Federal requirements that are more stringent or broader 
in scope than existing Federal requirements. RCRA section 3009 allows 
the States to impose standards more stringent than those in the Federal 
program. See also 40 CFR 271.1(i). If EPA promulgates a Federal 
requirement that is less stringent than an existing requirement, 
authorized States may, but are not required to, adopt the requirement 
regardless of whether it is a HSWA or non-HSWA requirement.

B. Effect on State Authorization

    This rule is promulgated pursuant to both non-HSWA authority (RCRA 
section 3001) and HSWA authority (RCRA section 3004(u)). The changes to 
Appendix VIII proposed in this rule are more stringent than the current 
Federal requirements because adding new substances to Appendix VIII 
expands the list of hazardous constituents that are subject to RCRA 
regulatory requirements. Therefore, States will be required to adopt 
and seek authorization for these changes. The Appendix VIII list of 
hazardous constituents does not by itself impose regulatory 
requirements. Rather, requirements to address hazardous constituents 
are found in various sections throughout the Federal hazardous waste 
regulations.
    Today's proposal, if finalized, would add nine PFAS, their salts, 
and their structural isomers to Appendix VIII for all purposes except 
corrective action, pursuant to RCRA section 3001. Today's action would 
also add these substances to Appendix VIII for corrective action 
purposes and add this listing action, as it would apply to corrective 
action purposes, to Table 1 in 40 CFR 271.1, pursuant to RCRA section 
3004(u). Given the dual nature of today's proposal, EPA would consider 
the final rule to be a non-HSWA rule promulgated under RCRA 3001 for 
all purposes except corrective action under RCRA 3004(u) and (v), and 
would consider the final rule to be a HSWA rule as applied to such 
corrective action (for example, as applied to the scope of hazardous 
constituents subject to corrective action under 40 CFR 264.101, the 
principal regulation implementing these provisions). Thus, the addition 
of the nine PFAS, their salts, and their structural isomers, as applied 
to RCRA section 3004(u) and (v) corrective action would become 
immediately effective in all States on the effective date (which would 
be provided in any final notice for the action); and EPA would 
implement the new rule as applied to corrective action in all States 
until those States become authorized for the new rule.
    States with authorized RCRA programs may already include one or 
more of these PFAS on their lists of hazardous constituents, since RCRA 
contemplates that States may promulgate regulations which are more 
stringent than the Federal RCRA requirements. These State regulations 
have not been assessed against the Federal regulations proposed today 
to determine whether they meet the authorization requirements. Thus, 
such a State would not be authorized to implement these regulations as 
RCRA requirements until the State program provisions are submitted to 
EPA and approved, pursuant to 40 CFR 271.21. Of course, States with 
existing regulations that are more stringent than or broader in scope 
than current Federal regulations may continue to administer and enforce 
their regulations as a matter of State law. In implementing the HSWA 
corrective action requirements, EPA will work with the States under 
agreements to avoid duplication of effort.

[[Page 8617]]

VII. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 14094: Modernizing Regulatory Review

    This action is a ``significant regulatory action'' as defined in 
Executive Order 12866, as amended by Executive Order 14094. 
Accordingly, EPA submitted this action to the Office of Management and 
Budget (OMB) for Executive Order 12866 review. Documentation of any 
changes made in response to Executive Order 12866 review is available 
in the docket. The EPA prepared an analysis of the potential impacts 
associated with this action. This analysis, the draft Economic 
Assessment of the Potential Costs, Benefits, and Other Impacts of the 
Proposed Rulemaking to List Specific PFAS as RCRA Hazardous 
Constituents (Ref. 41), is available in the docket for this action.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq., 
because it does not contain any information collection activities. 
Burden is defined at 5 CFR 1320.3(b).

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA, 5 
U.S.C. 601, et seq. EPA projects negligible direct impacts to regulated 
entities associated with the proposed rule (see Sections II.A. and 
II.D.). To the extent the proposed rule may result in indirect costs 
associated with corrective action, the small entity analysis in the 
draft Economic Assessment identifies 75 small entities that could be 
impacted.
    Because the proposed rule estimates negligible costs associated 
with direct impacts, EPA concludes the proposed rule will not result in 
a significant economic impact for a substantial number of small 
entities. Additional details of the small entity analysis, including 
information about the broader universe of TSDFs, are presented in the 
draft Economic Assessment of the Potential Costs, Benefits, And Other 
Impacts of the Proposed Rulemaking to List Specific PFAS as RCRA 
Hazardous Constituents (Ref. 41), available in the public docket for 
this action.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments because direct costs 
are projected to be negligible.

E. Executive Order 13132: Federalism

    This action does not have federalism implications based on EPA's 
policy for implementing E.O. 13132, entitled ``Federalism.'' It will 
not have substantial direct effects on the States or localities based 
on EPA's intergovernmental cost threshold for the E.O. 13132 analysis; 
it will not preempt State or local law or substantially affect the 
distribution of power and responsibilities among the various levels of 
government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175 because it does not have substantial direct 
effects on one or more Indian tribes, on the relationship between the 
Federal Government and Indian tribes, or on the distribution of power 
and responsibilities between the Federal Government and Indian tribes. 
There is only one facility on Tribal lands that EPA has identified that 
could be potentially affected by this rulemaking, and because the rule 
is not expected to result in substantial direct impacts (i.e., EPA 
anticipates negligible direct impacts) it is also not expected to 
result in adverse impacts on this tribal entity. Thus, Executive Order 
13175 does not apply to this action.
    However, consistent with the EPA Policy on Consultation and 
Coordination with Indian Tribes, the EPA intends to consult with and 
request comments from the affected tribe and other tribal officials 
that wish to consult with the Agency on this rulemaking.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045 (62 FR 19885, April 23, 1997) directs Federal 
agencies to include an evaluation of the health and safety effects of 
the planned regulation on children in Federal health and safety 
standards and explain why the regulation is preferable to potentially 
effective and reasonably feasible alternatives. This action is not 
subject to Executive Order 13045 because it is not ``economically 
significant'' as defined in Executive Order 12866, and because it does 
not concern an environmental health risk or safety risk. This action, 
which proposes to add nine PFAS, their salts, and their structural 
isomers as RCRA hazardous constituents, does not itself address 
environmental health or safety risks. Therefore, EPA does not believe 
there are disproportionate risks to children.
    However, EPA's 2021 Policy on Children's Health applies to this 
action, which requires EPA to consider early life exposures and 
lifelong health consistently and explicitly in all human health 
decisions.\10\ To the extent that the proposed rulemaking leads to the 
remediation of select PFAS, potential exposure to these PFAS is 
expected to be reduced for the population living in close proximity to 
these sites, including susceptible subpopulations such as workers and 
children. Additionally, to the extent that the proposed rule reduces 
exposure, a reduction in the risks of adverse health effects in 
children might be expected, as well as associated health care cost 
savings. The information that EPA used to evaluate the toxicity and 
health effects of these PFAS, which includes many studies that looked 
at effects during development and on children, is described above in 
the Section Summary of toxicity and health effects information for the 
nine PFAS and the supporting documents in the public docket for this 
action.
---------------------------------------------------------------------------

    \10\ https://www.epa.gov/system/files/documents/2021-10/2021-policy-on-childrens-health.pdf.
---------------------------------------------------------------------------

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This action is not a ``significant energy action'' because it is 
not related to, or likely to have a significant adverse effect on, the 
supply, distribution, or use of energy. This action proposes to add 
nine PFAS, their salts, and structural isomers as RCRA hazardous 
constituents, and thus, does not involve the supply, distribution, or 
use of energy.

I. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards.

[[Page 8618]]

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations; Executive 
Order 14096: Revitalizing Our Nation's Commitment to Environmental 
Justice for All

    Executive Order 14096 (88 FR 25251, Apr. 26, 2023) directs Federal 
agencies to advance the goal of environmental justice for all. This 
action builds upon and supplements the efforts of Executive Order 12898 
(59 FR 7629, February 16, 1994) to address environmental justice.
    The EPA believes that the human health or environmental conditions 
that exist prior to this action may result in or have the potential to 
result in disproportionate and adverse human health or environmental 
effects on communities with environmental justice concerns.
    Several key demographic categories were analyzed relative to the 
universe of facilities potentially affected by the proposed rule. This 
proposed regulation identifies groundwater and surface water as 
potential sources of exposure for the identified PFAS. Due to 
uncertainty surrounding the location of PFAS releases, this analysis 
additionally considers a subset of the total universe of facilities 
which are associated with a potentially higher likelihood of handling 
PFAS, and where corrective action for PFAS may occur. These facilities 
are identified based on:

     A list of NAICS codes (at the 6-digit level) used by 
Salvatore et al. (2022) for identifying presumptive PFAS 
contamination across the U.S.\11\
---------------------------------------------------------------------------

    \11\ See Salvatore et al., ``Presumptive Contamination: A New 
Approach to PFAS Contamination Based on Likely Sources'', Environ 
Sci Technol Lett. Vol. 9, Issue 11. November 8, 2022. Accessed at: 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9648201/.
---------------------------------------------------------------------------

     EPA's proposed rule, `Designation of Perfluorooctanoic 
Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) as CERCLA 
Hazardous Substances', identified industries (at the 6-digit NAICS 
level) historically associated with PFAS; therefore, TSDFs in these 
industries are also assumed to have higher likelihood of handling 
PFAS.
     The PFAS Analytical Tools page in EPA's Enforcement and 
Compliance History Online (ECHO) includes a list of industry sectors 
potentially associated with PFAS, defined by 6-digit NAICS.\12\ Any 
permitted TSDFs within these industries are also assumed to have a 
higher likelihood of handling PFAS.
---------------------------------------------------------------------------

    \12\ See United States Environmental Protection Agency, PFAS 
Analytical Tools, available at https://echo.epa.gov/trends/pfas-tools.
---------------------------------------------------------------------------

     If a TSDF in the regulatory universe reported any of 
the specific PFAS proposed for addition to 40 CFR part 261, Appendix 
VIII in the EPA's Toxic Release Inventory (TRI),\13\ that facility 
is also assumed to have a higher likelihood of handling PFAS.
---------------------------------------------------------------------------

    \13\ PFAS chemicals included in search: PFOS, PFOA, PFBS, HFPO-
DA (GenX), PFNA, PFHxS, PFDA, PFHxA, and PFBA. Environmental 
Protection Agency, ``Envirofacts: TRI Search'', December 2022. 
Accessed at: https://www.epa.gov/enviro/tri-search.

    The sites identified as having potential association with PFAS make 
them a reasonable proxy for identifying where corrective action for 
these substances may be required and offer an associated surrounding 
demographic context. However, the spatial distribution and predicted 
risk factor of a PFAS release cannot be certain without further site-
specific investigation into a facility's waste handling capacity, 
proximity to population centers, and interconnectivity of local 
environmental resources.
    The EPA believes that this action may indirectly reduce existing 
disproportionate and adverse effects on communities with environmental 
justice concerns. To the extent that the proposed rule leads to the 
remediation of releases for any of the nine PFAS, their salts, and 
their structural isomers that EPA proposes to list as RCRA hazardous 
constituents, health risks for populations living in close proximity to 
these sites (particularly populations that rely on private well water 
near these sites) may decline. As groundwater and surface water have 
been identified as potential exposure pathways of PFAS, the inclusion 
of private well usage rates in areas surrounding facilities known to 
use, produce, or release PFAS provides additional information about 
populations that may have a potentially higher likelihood of negative 
health outcomes from a PFAS release. In some cases, focusing the 
analysis solely on those potentially more vulnerable populations served 
by private wells reveals further demographic disparities compared to 
the total U.S. population served by private wells.
    Details of the full analysis and findings are presented in the 
draft Economic Assessment of the Potential Costs, Benefits, and Other 
Impacts of the Proposed Rulemaking to List Specific PFAS as RCRA 
Hazardous Constituents (Ref. 41), which can be found in the public 
docket for this action.
    Better understanding the impacts of a PFAS release and the factors 
that determine the magnitude of effects on the surrounding human and 
natural environment will potentially become more apparent over time, 
allowing for improved information and a more robust analysis on any 
disproportionate and adverse outcomes experienced by populations with 
EJ concerns. This improved information would not increase risk for 
communities with EJ concerns and may improve the speed and design of 
remediation. The EPA is committed to minimizing and/or eliminating 
existing barriers and burdens that communities with EJ concerns may 
encounter related to accessing data and information associated with 
this rulemaking, if finalized. EPA seeks comment on strategies to 
improve access to associated data, which may become available in RCRA 
Info, for communities with environmental justice concerns.

VIII. References

1. U.S. EPA. (2023). PFOA, PFOS and other PFAS: Basic information on 
PFAS. U.S. Environmental Protection Agency. https://www.epa.gov/pfas/basic-information-pfas.
2. ATSDR. (2023). PFAS and Your Health. https://www.atsdr.cdc.gov/pfas/index.html.
3. Public Employees for Environmental Responsibility (PEER) to the 
Administrator of EPA concerning RCRA Regulation of a Class of Wastes 
Containing PFAS. September 19, 2019. https://www.epa.gov/system/files/documents/2021-09/peer_pfas_rulemaking_petition_metadata_added.pdf.
4. Petition for Rulemaking from Environmental Law Clinic of 
University of California, Berkeley to the Administrator of EPA 
concerning RCRA Regulation of Wastes Containing Long-Chain PFASs and 
GenX Chemicals. January 15, 2020. https://www.epa.gov/system/files/documents/2021-09/pfas_petition_for_haz_waste_jan_2020_metadata_added.pdf.
5. Petition from the Governor of New Mexico to the Administrator of 
EPA concerning action on PFAS under RCRA. June 23, 2021. https://www.epa.gov/system/files/documents/2021-10/508compliant_ezd5442262_2021-06-23-governor-letter-to-epa-for-pfas-petition.pdf-incoming-document.pdf.
6. EPA Administrator's letter to the Governor of New Mexico in 
response to the petition on PFAS. October 26, 2021. https://www.epa.gov/system/files/documents/2021-10/oct_2021_response_to_nm_governor_pfas_petition_corrected.pdf.
7. NIEHS. (2023). Perfluoroalkyl and Polyfluoroalkyl Substances 
(PFAS). https://www.niehs.nih.gov/health/topics/agents/pfc/index.cfm.
8. Press release on EPA's response to New Mexico Governor's petition 
on PFAS. October 26, 2021. https://www.epa.gov/newsreleases/epa-responds-new-mexico-governor-and-acts-address-pfas-under-hazardous-waste-law.
9. U.S. EPA. (2016). Health effects support document for 
perfluorooctanoic acid (PFOA). U.S. Environmental Protection

[[Page 8619]]

Agency Office of Water. EPA-822-R-16-003. https://www.epa.gov/sites/default/files/2016-05/documents/pfoa_hesd_final-plain.pd.f
10. U.S. EPA. (2023). Public Comment Draft--Toxicity Assessment and 
Proposed Maximum Contaminant Level Goal (MCLG) for Perfluorooctanoic 
Acid (PFOA) (CASRN 335-67-1) in Drinking Water. EPA-822-P-23-005.
11. U.S. EPA. (2023). Public Comment Draft--Toxicity Assessment and 
Proposed Maximum Contaminant Level Goal (MCLG) for Perfluorooctane 
Sulfonic Acid (PFOS) (CASRN 1763-23-1) in Drinking Water. EPA-822-P-
23-007.
12. U.S. EPA. (2022). Transmittal of the Science Advisory Board 
Report titled, ``Review of EPA's Analyses to Support EPA's National 
Primary Drinking Water Rulemaking for PFAS.'' EPA-22-008. https://sab.epa.gov/ords/sab/f?p=114:12:15255596377846.
13. U.S. EPA. (2023). EPA Response to Final Science Advisory Board 
Recommendations (August 2022) on Four Draft Support Documents for 
the EPA's Proposed PFAS National Primary Drinking Water Regulation. 
EPA-822-D-23-001.
14. U.S. EPA. (2016). Health effects support document for 
perfluorooctane sulfonate (PFOS). U.S. Environmental Protection 
Agency Office of Water. https://www.epa.gov/sites/default/files/2016-05/documents/pfos_hesd_final_508.pdf.
15. U.S. EPA. (2021). Human Health Toxicity Values for 
Perfluorobutane Sulfonic Acid (CASRN 375-73-5) and Related Compound 
Potassium Perfluorobutane Sulfonate (CASRN 29420-49-3). U.S. 
Environmental Protection Agency Office of Research and Development. 
https://www.epa.gov/chemical-research/learn-about-human-health-toxicity-assessment-pfbs.
16. U.S. EPA. (2021). 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.'' U.S. Environmental Protection Agency Office of Water. 
https://www.epa.gov/system/files/documents/2021-10/genx-chemicals-toxicity-assessment_tech-edited_oct-21-508.pdf.
17. U.S. EPA. (2022). IRIS Toxicological Review of Perfluorobutanoic 
Acid (PFBA) and Related Salts (Final Report). U.S. Environmental 
Protection Agency Office of Research and Development. https://iris.epa.gov/static/pdfs/0701tr.pdf.
18. ATSDR. (2021). Toxicological profile for perfluoroalkyls: final. 
Atlanta, GA: U.S. Department of Health and Human Services, Centers 
for Disease Control and Prevention, Agency for Toxic Substances and 
Disease Registry. https://stacks.cdc.gov/view/cdc/59198.
19. Grandjean et al. (2012). ``Serum Vaccine Antibody Concentrations 
in Children Exposed to Perfluorinated Compounds'' JAMA 307 (4): 391-
397. DOI:10.1001/jama.2011.2034.
20. Grandjean et al. (2017). ``Serum Vaccine Antibody Concentrations 
in Adolescents Exposed to Perfluorinated Compounds'' Environ Health 
Perspect 125 (7): 077018 DOI: 10.1289/EHP275.
21. Grandjean et al. (2017). ``Estimated exposures to perfluorinated 
compounds in infancy predict attenuated vaccine antibody 
concentrations at age 5-years'' J Immunotoxicol 14 (1): 188-195. 
DOI: 10.1080/1547691X.2017.1360968.
22. Budtz-Jorgensen and Grandjean. (2018). ``Application of 
benchmark analysis for mixed contaminant exposures: Mutual 
adjustment of perfluoroalkylate substances associated with 
immunotoxicity'' PLoS One 13 (10): e0205388. DOI: 10.1371/
journal.pone.0205388.
23. U.S. EPA. (2009). Consent Order and Determinations Supporting 
Consent Order for Premanufacture Notice Numbers: P-08-508 and P-08-
509. EPA, Office of Pollution Prevention and Toxics, Washington, DC. 
https://chemview.epa.gov/chemview/proxy?filename=sanitized_consent_order_p_08_0508c.pdf.
24. Kielsen et al. (2016). Antibody response to booster vaccination 
with tetanus and diphtheria in adults exposed to perfluorinated 
alkylates. J Immunotoxicol 13(2):270-273.
25. U.S. EPA. (2020). ORD Staff Handbook for Developing IRIS 
Assessments (Public Comment Draft, Nov 2020). EPA/600/R-20/137. EPA, 
Office of Research and Development, Washington, DC.
26. DuPont-18405-1037: E.I. du Pont de Nemours and Company. 2010. An 
Oral (Gavage) Reproduction/Developmental Toxicity Screening Study of 
H-28548 in Mice. U.S. EPA OPPTS 870.3550; OECD Test Guideline 421. 
Study conducted by WIL Research Laboratories, LLC (Study Completion 
Date: December 29, 2010), Ashland, OH.
27. Huang et al. (2018). Serum polyfluoroalkyl chemicals are 
associated with risk of cardiovascular diseases in national US 
population. Environ Int 119:37-46. http://doi.org/10.1016/j.envint.2018.05.051.
28. Lind et al. (2017). Prenatal exposure to perfluoroalkyl 
substances and anogenital distance at 3 months of age in a Danish 
mother-child cohort. Reprod Toxicol 68:200-206. http://doi.org/10.1016/j.reprotox.2016.08.019.
29. Loveless et al. (2006). ``Comparative responses of rats and mice 
exposed to linear/branched, linear, or branched ammonium 
perfluorooctanoate (APFO)'' Toxicology 220(2-3): 203-17. DOI: 
10.1016/j.tox.2006.01.003.
30. Loveless et al. (2009). ``Toxicological evaluation of sodium 
perfluorohexanoate'' Toxicology 264 (1-2): 32-44. DOI: 10.1016/
j.tox.2009.07.011.
31. U.S. EPA. (2023). IRIS Toxicological Review of Perfluorodecanoic 
Acid (PFDA) and Related Salts (Draft Report). U.S. Environmental 
Protection Agency Office of Research and Development. https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=354408.
32. U.S. EPA. (2023). IRIS Toxicological Review of Perfluorohexanoic 
Acid (PFHxA) and Related Salts (Final Report). U.S. Environmental 
Protection Agency Office of Research and Development. https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=357314.
33. Lieder et al. (2009). ``A two-generation oral gavage 
reproduction study with potassium perfluorobutanesulfonate (K+PFBS) 
in Sprague Dawley rats.'' Toxicology 259 (1-2): 33-45. DOI: 10.1016/
j.tox.2009.01.027.
34. George and Andersen (1986). ``Toxic effects of nonadecafluoro-n-
decanoic acid in rats.'' Toxicology and Applied Pharmacology 85(2): 
169-180. DOI: 10.1016/0041-008X(86)90110-9.
35. Bijland et al. (2011). ``Perfluoroalkyl sulfonates cause alkyl 
chain length-dependent hepatic steatosis and hypolipidemia mainly by 
impairing lipoprotein production in APOE*3-Leiden CETP mice.'' 
Toxicol Sci 123(1): 290-303. DOI: 10.1093/toxsci/kfr142.
36. Butenhoff et al. (2004). ``The reproductive toxicology of 
ammonium perfluorooctanoate (APFO) in the rat.'' Toxicology 196 (1-
2): 95-116. DOI: 10.1016/j.tox.2003.11.005.
37. Lau et al. (2006). ``Effects of perfluorooctanoic acid exposure 
during pregnancy in the mouse.'' Toxicol Sci 90(2): 510-518. DOI: 
10.1093/toxsci/kfj105.
38. Lou et al. (2009). ``Modeling single and repeated dose 
pharmacokinetics of PFOA in mice.'' Toxicol Sci 107(2): 331-41. DOI: 
10.1093/toxsci/kfn234.
39. Ankley et al. (2004). ``Partial life-cycle toxicity and 
bioconcentration modeling of perfluorooctanesulfonate in the 
northern leopard frog (Rana pipiens).'' Environmental Toxicology and 
Chemistry 23(11): 2745-2755. DOI: 10.1897/03-667.
40. Timmermann et al. (2022). ``Concentrations of tetanus and 
diphtheria antibodies in vaccinated Greenlandic children aged 7-12 
years exposed to marine pollutants, a cross sectional study.'' 
Environmental Research 203. DOI: 10.1016/j.envres.2021.111712.
41. U.S. EPA. (2023). Draft Economic Assessment of the Potential 
Costs, Benefits, and Other Impacts of the Proposed Rulemaking to 
List Specific PFAS as RCRA Hazardous Constituents. U.S. 
Environmental Protection Agency Office of Land and Emergency 
Management.
42. Shearer et al. (2021). ``Serum Concentrations of Per- and 
Polyfluoroalkyl Substances and Risk of Renal Cell Carcinoma.'' J 
Natl Cancer Inst. 113(5): 580-587. DOI: 10.1093/jnci/djaa143.
43. Rhee et al. (2023). ``Serum Concentrations of Per- and 
Polyfluoroalkyl Substances and Risk of Renal Cell Carcinoma in the 
Multiethnic Cohort Study.'' Environmental International Volume 180, 
108197. https://doi.org/10.1016/J.envint.2023.108197.

[[Page 8620]]

44. U.S. EPA. (2023). IRIS Toxicological Review of 
Perfluorohexanesulfonic Acid (PFHxS) and Related Salts (Draft 
Report). U.S. Environmental Protection Agency Office of Research and 
Development. https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=355410.
45. U. S. EPA (2023). External Panel Peer Review of EPA's Draft 
``IRIS Toxicological Review of Perfluorodecanoic Acid (PFDA) and 
Related Salts'' (Final Peer Review Report). U.S. Environmental 
Protection Agency Office of Research and Development. https://cfpub.epa.gov/ncea/iris_drafts/recordisplay.cfm?deid=354408.

List of Subjects

40 CFR Part 261

    Environmental protection, Hazardous waste, Recycling, Reporting and 
recordkeeping requirements.

40 CFR Part 271

    Administrative practice and procedure, Confidential business 
information, Environmental protection, Hazardous materials 
transportation, Hazardous waste, Indians--lands, Intergovernmental 
relations, penalties, and Reporting and recordkeeping requirements.

Michael S. Regan,
Administrator.
    For the reasons set out in the preamble, EPA proposes to amend 
title 40, chapter I of the Code of Federal Regulations as follows:

PART 261--IDENTIFICATION AND LISTING OF HAZARDOUS WASTE

0
1. The authority citation for part 261 continues to read as follows:

    Authority: 42 U.S.C. 6905, 6912(a), 6921, 6922, 6924(y) and 
6938.

0
2. Appendix VIII to Part 261 is amended by adding in alphabetical order 
the following entries:

Appendix VIII to Part 261--Hazardous Constituents

* * * * *

------------------------------------------------------------------------
                                                   Chemical
         Common name               Chemical       abstracts    Hazardous
                                abstracts name       No.       waste No.
------------------------------------------------------------------------
HFPO-DA......................  Hexafluoropropyl   13252-13-6  ..........
                                ene oxide-dimer
                                acid.
HFPO-DA salts and enantiomers
PFBA.........................  Perfluorobutanoi     375-22-4  ..........
                                c acid.
PFBA salts and structural
 isomers.
PFBS.........................  Perfluorobutanes     375-73-5  ..........
                                ulfonic acid.
PFBS salts and structural
 isomers.
PFDA.........................  Perfluorodecanoi     335-76-2  ..........
                                c acid.
PFDA salts and structural
 isomers.
PFHxA........................  Perfluorohexanoi     307-24-4  ..........
                                c acid.
PFHxA salts and structural
 isomers.
PFHxS........................  Perfluorohexanes     355-46-4  ..........
                                ulfonic acid.
PFHxS salts and structural
 isomers.
PFNA.........................  Perfluorononanoi     375-95-1  ..........
                                c acid.
PFNA salts and structural
 isomers.
PFOA.........................  Perfluorooctanoi     335-67-1  ..........
                                c acid.
PFOA salts and structural
 isomers.
PFOS.........................  Perfluorooctanes    1763-23-1  ..........
                                ulfonic acid.
PFOS salts and structural
 isomers.
------------------------------------------------------------------------

PART 271--REQUIREMENTS FOR AUTHORIZATION OF STATE HAZARDOUS WASTE 
PROGRAMS

0
3. The authority citation for Part 271 continues to read as follows:

    Authority: 42 U.S.C. 6905, 6912(a), 6926, and 6939g.

0
4. Section 271.1(j) is amended by adding the following entry to Table 1 
in chronological order by date of publication to read as follows.
---------------------------------------------------------------------------

    \6\ This listing implements HSWA only to the extent it applies 
to 40 CFR 264.101 and 270.14(d) and to 40 CFR Subpart S.
---------------------------------------------------------------------------


Sec.  271.1  Purpose and scope.

    (j) * * *

               Table 1--Regulations Implementing the Hazardous and Solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
                                                                    Federal Register
          Promulgation date              Title of regulation           reference              Effective date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
[DATE OF PUBLICATION OF FINAL RULE]..  Listing of certain       [FEDERAL REGISTER PAGE   [EFFECTIVE DATE OF
                                        PFAS.\6\                 NUMBERS FOR FINAL        FINAL RULE]
                                                                 RULE].
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


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[FR Doc. 2024-02324 Filed 2-7-24; 8:45 am]
BILLING CODE 6560-50-P