Document ID: EPA-HQ-OW-2018-0614-0001
Agency: epa
Document Type: Notice
Title: Draft Human Health Toxicity Assessments for Hexafluoropropylene Oxide Dimer Acid and its Ammonium Salt (GenX Chemicals) and for Perfluorobutane Sulfonic Acid (PFBS) and Related Compound Potassium Perfluorobutane Sulfonate
Posted Date: 2018-11-21T05:00Z

[Federal Register Volume 83, Number 225 (Wednesday, November 21, 2018)]
[Notices]
[Pages 58768-58770]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-25422]

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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OW-2018-0614; FRL-9986-79-OW]

Request for Public Review and Comment: Draft Human Health 
Toxicity Assessments for Hexafluoropropylene Oxide Dimer Acid and Its 
Ammonium Salt (GenX Chemicals) and for Perfluorobutane Sulfonic Acid 
(PFBS) and Related Compound Potassium Perfluorobutane Sulfonate

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of public comment period.

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SUMMARY: The Environmental Protection Agency (EPA) is announcing a 60-
day public comment period associated with the release of two draft 
toxicity assessments for public comment:
     Draft Human Health Toxicity Values for Hexafluoropropylene 
Oxide (HFPO) Dimer Acid and its Ammonium Salt (GenX Chemicals).
     Draft Human Health Toxicity Values for Perfluorobutane 
Sulfonic Acid (PFBS) and Related Compound Potassium Perfluorobutane 
Sulfonate.
    The EPA developed the draft assessments to provide the health 
effects information available for GenX chemicals and PFBS and describe 
how that information was used to derive draft toxicity values. These 
draft toxicity assessments underwent independent, external expert peer 
review in June-July 2018. Following closure of this 60-day public 
comment period, the EPA will consider the comments, revise the draft 
documents, and consider the need for additional peer review, as 
appropriate, and then publish final toxicity assessments. The toxicity 
assessments for GenX chemicals and PFBS are scientific and technical 
reports that include toxicity values associated with potential 
noncancer health effects following oral exposure (in this case, oral 
reference doses [RfDs]). These assessments evaluate human health 
hazards. The toxicity assessments and the values contained within are 
not risk assessments as they do not include exposure assessments or 
provide a risk characterization. Further, the toxicity assessments do 
not address the legal, political, social, economic, or technical 
considerations involved in risk management. When issued, the toxicity 
assessments can be used by the EPA, states, tribes, and local 
communities, along with specific exposure and other relevant 
information, to determine, under the appropriate regulations and 
statutes, if and when it is necessary to

[[Page 58769]]

take action to address potential risk associated with human exposures 
to these per- and polyfluoroalkyl substances (PFAS) chemicals.

DATES: Comments must be received on or before January 22, 2019.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2018-0614, to the public docket at: http://www.regulations.gov. Follow 
the online instructions for submitting comments. Once submitted, 
comments cannot be edited or withdrawn. The EPA may publish any comment 
received to its public docket. Do not submit electronically any 
information you consider to be Confidential Business Information (CBI) 
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. The 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 CBI or multimedia submissions, 
and general guidance on making effective comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: 
    For information on the docket, contact the docket manager: Assem 
Akram, Docket Manager, EPA Docket Center, telephone: (202) 566-0226; or 
email: [email protected].
    For technical information on GenX chemicals: Dr. Jamie Strong, 
Health and Ecological Criteria Division, Office of Water (Mail Code 
4304T), Environmental Protection Agency, 1200 Pennsylvania Avenue NW, 
Washington, DC 20460; telephone: (202) 566-0056; or email: 
[email protected].
    For technical information on PFBS: Dr. Samantha Jones, National 
Center for Environmental Assessment, Office of Research and Development 
(Mail Code 8602R), Environmental Protection Agency, 1200 Pennsylvania 
Avenue NW, Washington, DC 20460; telephone: 202-564-6794; or email: 
[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

    Supporting documents are available in the public docket for this 
ICR (under Docket ID number EPA-HQ-OW-2018-0614. The docket can be 
viewed online at http://www.regulations.gov or in person at the EPA 
Docket Center, WJC West, Room 3334, 1301 Constitution Ave. NW, 
Washington, DC. The telephone number for the Docket Center is 202-566-
1744. For additional information about the EPA's public docket, visit 
http://www.epa.gov/dockets.

A. Does this action apply to me?

    This request for public comment will not impose any requirements on 
anyone. Instead, this action notifies interested parties of the 
availability of draft toxicity assessments for GenX Chemicals and PFBS 
for public comment. It should be noted that when final these toxicity 
assessments may be used by the EPA, states, tribes, and local 
communities, along with specific exposure and other relevant 
information, to determine, under the appropriate regulations and 
statutes, if and when it is necessary to take action to address 
potential risk associated with human exposures to these PFAS chemicals.

B. What should I consider as I prepare my comments for the EPA?

    1. Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2018-0614, 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. The EPA may 
publish any comment received to its public docket. Do not submit 
electronically any information you consider to be Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Clearly mark the part or all of the information that you 
claim to be CBI. For CBI information in a disk or CD-ROM that you mail 
to the EPA, mark the outside of the disk or CD-ROM as CBI and then 
identify electronically within the disk or CD-ROM the specific 
information that is claimed as CBI. In addition to one complete version 
of the comment that includes information claimed as CBI, a copy of the 
comment that does not contain the information claimed as CBI must be 
submitted for inclusion in the public docket. Information so marked 
will not be disclosed except in accordance with procedures set forth in 
the Code of Federal Regulations (CFR) at 40 CFR part 2. 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. The 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 CBI or multimedia submissions, and general 
guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

II. What are GenX chemicals and PFBS?

    GenX chemicals and PFBS are man-made, fluorinated organic chemicals 
that are part of a larger group of manmade chemicals referred to as 
per- and polyfluoroalkyl substances (PFAS). PFAS are used in many 
applications because of their unique physical properties such as 
resistance to high and low temperatures, resistance to degradation, and 
nonstick characteristics. GenX is a trade name for a processing aid 
technology used to make high-performance fluoropolymers without the use 
of perfluorooctanoic acid (PFOA). Hexafluoropropylene oxide (HFPO) 
dimer acid and its ammonium salt are the major chemicals associated 
with the GenX processing aid technology and the focus of the draft 
assessment. PFBS is a four-carbon PFAS that was developed as a 
replacement for longer-chain PFAS, which have demonstrated 
environmental persistence, long half-lives and bioaccumulation in 
humans. PFBS has been integrated into various consumer products and 
applications.

III. What are EPA's draft toxicity assessments?

    The EPA's draft toxicity assessments for GenX Chemicals and PFBS 
provide information on hazard identification and dose-response, 
including draft subchronic and chronic oral reference doses (RfDs) for 
each chemical. Overall, the available oral toxicity studies demonstrate 
that the liver is particularly sensitive to GenX chemicals, and the 
thyroid and kidney are sensitive to PFBS. The draft toxicity 
assessments underwent independent, external peer review in June and 
July 2018 and were revised accordingly.
    In the risk assessment/risk management paradigm, a toxicity 
assessment is on the risk assessment side of the paradigm. The draft 
toxicity assessments for GenX chemicals and PFBS address the first two 
steps (Step 1. Hazard Identification and Step 2. Dose-Response) of the 
four-step risk assessment process described by the National Academy of 
Science in 1983 as ``the characterization of the potential adverse 
health effects of human exposures to environmental hazards.''

[[Page 58770]]

Characterizing risk involves integrating information on hazard, dose-
response, and exposure. For further details about risk assessments see: 
https://www.epa.gov/risk/conducting-human-health-risk-assessment.
    When issued, the toxicity values for GenX chemicals and PFBS can be 
combined with specific exposure information (Step 3. Exposure 
Assessment) by government and private entities to help characterize 
(Step 4. Risk Characterization) potential public health risks 
associated with exposure to these chemicals. Thus, once the GenX 
chemicals and PFBS assessments are issued, the EPA will work with our 
state, tribal, and local partners to provide technical assistance, 
including information about appropriate regulations and statutes, as 
they begin considering the final values in relevant exposure scenarios. 
It is the risk management part of the risk assessment/risk management 
paradigm where the supporting science, as well as statutory and legal 
considerations, risk management options, public health considerations, 
cost/benefit considerations, economic factors, social factors, and 
other considerations are weighed.
    The EPA recognizes that humans have the potential to be exposed to 
complex mixtures of PFAS and other chemicals and pathogens through 
drinking water and other exposure sources. The EPA's draft assessments 
for GenX chemicals and PFBS focus solely on the potential human health 
effects associated with oral exposure to each chemical; they do not 
consider potential cumulative (mixture) effects of GenX chemicals and 
PFBS or their possible interactions with other PFAS and/or other 
chemicals. This would involve a more complex assessment that would need 
to consider and evaluate mechanisms of action and endpoints of concern 
for each of the chemicals in the mixture.

IV. Why is the EPA releasing draft toxicity assessments for these 
chemicals?

    The EPA is issuing the draft toxicity assessments for PFBS and GenX 
chemicals for public comment to give interested stakeholders and the 
public an opportunity to provide input to the Agency. The public will 
have 60 days after publication in the Federal Register to provide 
input. At the end of the comment period, the EPA will evaluate the 
input, make appropriate revisions, and finalize the toxicity 
assessments. Once the toxicity assessments are issued, the EPA will 
work with our state, tribal, and local partners to provide technical 
assistance, as they begin using the final values in relevant exposure 
scenarios to generate risk assessments to support risk management 
decisions.

V. Solicitation of Public Comment

    During the 60-day comment period, the EPA is soliciting public 
comments regarding the science and technical approaches used in the 
derivation of the draft toxicity assessments for GenX chemicals and 
PFBS.
    In the PFBS assessment, due to the lack of epidemiological studies 
demonstrating adverse effects in humans, the EPA derived candidate 
subchronic RfDs (see Section 6.1.1 of the toxicity assessment) and 
candidate chronic RfDs (see Section 6.1.2 of the toxicity assessment) 
for both thyroid effects and kidney effects in rodent toxicity studies. 
In light of the consistent observation of the thyroid effects across 
life stages and the greater dose-response sensitivity, relative to the 
kidney effects, the EPA is proposing to base the overall subchronic and 
chronic RfDs on the thyroid effects and is requesting public review and 
comment on this proposal in addition to the approaches and conclusions 
in the PFBS assessment. Additionally, as described in Section 6.1 of 
the PFBS toxicity assessment, decreased serum total T4 (thyroxine) in 
newborn mice was used as the basis for the thyroid-related candidate 
RfDs. Peer reviewers provided comments on thyroid effects and this 
choice of endpoint. See pages 15-25 and 31-32 in the Response to Peer 
Review Comments on the Draft Human Health Toxicity Values for 
Perfluorobutane Sulfonic Acid (CASRN 375-73-5) and Related Compound 
Potassium Perfluorobutane Sulfonate (CASRN 29420-49-3) for the array of 
peer review comments on these topics and the EPA's responses. These 
supporting documents are available in the public docket for this ICR 
(under Docket ID number EPA-HQ-OW-2018-0614. Comments from the public 
are requested on the thyroid effects, this choice of endpoint, as well 
as the discussion on thyroid hormone economy in humans and animals (see 
Section 6.1 of the PFBS toxicity assessment).
    These draft assessments are not final as described in the EPA's 
information quality guidelines, and do not represent Agency policy or 
views. The EPA will consider all public comments submitted in response 
to this notice when revising these documents.

    Dated: November 14, 2018.
David P. Ross,
Assistant Administrator, Office of Water.
[FR Doc. 2018-25422 Filed 11-20-18; 8:45 am]
BILLING CODE 6560-50-P