[Federal Register Volume 90, Number 243 (Monday, December 22, 2025)]
[Proposed Rules]
[Pages 59767-59783]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-23566]
=======================================================================
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63
[EPA-HQ-OAR-2024-0392; FRL-7688-03-OAR]
RIN 2060-AU75
Petition To Delist Hazardous Air Pollutant: 2-Butoxyethyl
Benzoate (2-BEB)
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The U.S. Environmental Protection Agency (EPA or Agency) is
proposing to grant a petition to remove
[[Page 59768]]
2-Butoxyethyl benzoate (2-BEB) (Chemical Abstract Service (CAS) No.
5451-76-3) from the glycol ethers category in the list of hazardous air
pollutants (HAP) in Clean Air Act (CAA). The EPA proposes to find that
there are adequate data on the health or environmental effects of 2-BEB
to support the request for removal. This action also details a
streamlined approach to the review process of future petitions.
DATES: Comments must be received on or before February 20, 2026.
Public hearing: If anyone contacts us requesting a public hearing
on or before Saturday, December 27, 2025, we will hold a virtual public
hearing. See SUPPLEMENTARY INFORMATION for information on requesting
and registering for a public hearing.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2024-0392, by any of the following methods:
Federal eRulemaking Portal: https://www.regulations.gov
(our preferred method). Follow the online instructions for submitting
comments.
Email: [email protected]. Include Docket ID No. EPA-
HQ-OAR-2024-0392 in the subject line of the message.
Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2024-0392.
Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Docket ID No. EPA-HQ-OAR-2024-0392, 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 SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: For information about this proposed
action, contact Marisa Pfohl, Impacts and Ambient Standards Division
(C539-02), Office of Clean Air Programs, U.S. Environmental Protection
Agency, 109 T.W. Alexander Drive, P.O. Box 12055 RTP, North Carolina
27711; telephone number: (919) 541-7607; email address:
[email protected]. For additional information, see https://www.epa.gov/haps/deletion-2-butoxyethyl-benzoate-2-beb-glycol-ethers-category-clean-air-act-list-hazardous-air.
SUPPLEMENTARY INFORMATION:
Participation in virtual public hearing. To request a virtual
public hearing, contact the public hearing team at (888) 372-8699 or by
email at [email protected]. If requested, the virtual hearing
will be held on January 12, 2026. The EPA will announce further details
at https://www.epa.gov/haps/deletion-2-butoxyethyl-benzoate-2-beb-glycol-ethers-category-clean-air-act-list-hazardous-air. We note that
if a hearing is requested, the planned schedule for the hearing will be
provided on this website, but the EPA may close a session 15 minutes
after the last pre-registered speaker has testified if there are no
additional speakers.
If a public hearing is requested, the EPA will begin pre-
registering speakers for the hearing no later than one business day
after a request has been received. To register to speak at the virtual
hearing, please use the online registration form available at https://www.epa.gov/haps/deletion-2-butoxyethyl-benzoate-2-beb-glycol-ethers-category-clean-air-act-list-hazardous-air or contact the public hearing
team at (888) 372-8699 or by email at [email protected]. The
last day to pre-register to speak at the hearing will be Saturday,
January 3, 2026. Prior to the hearing, the EPA will post a general
agenda that will list pre-registered speakers at: https://www.epa.gov/haps/deletion-2-butoxyethyl-benzoate-2-beb-glycol-ethers-category-clean-air-act-list-hazardous-air.
The EPA will make every effort to follow the schedule as closely as
possible on the day of the hearing; however, please plan for the
hearings to run either ahead of schedule or behind schedule.
Each commenter will have four minutes to provide oral testimony.
The EPA encourages commenters to submit a copy of their oral testimony
as written comments to the rulemaking docket. The EPA may ask
clarifying questions during the oral presentations but will not respond
to the presentations at that time. Written statements and supporting
information submitted during the comment period will be considered with
the same weight as oral testimony and supporting information presented
at the public hearing.
Please note that any updates made to any aspect of the hearing will
be posted online at https://www.epa.gov/haps/deletion-2-butoxyethyl-benzoate-2-beb-glycol-ethers-category-clean-air-act-list-hazardous-air.
While the EPA expects the hearing to go forward as described in this
section, please monitor our website or contact the public hearing team
at (888) 372-8699 or by email at [email protected] to determine
if there are any updates. The EPA does not intend to publish a document
in the Federal Register announcing updates.
If you require special accommodation such as audio description,
please pre-register for the hearing with the public hearing team and
describe your needs by Monday, December 29, 2025. The EPA may not be
able to arrange accommodations without advanced notice.
Docket. The EPA has established a docket for this rulemaking under
Docket ID No. EPA-HQ-OAR-2024-0392. All documents in the docket are
listed at https://www.regulations.gov. Although listed, some
information is not publicly available, e.g., Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. The EPA does not place certain other material, such as
copyrighted material, on the internet; this material is publicly
available only as pdf versions accessible only on EPA computers in the
docket office reading room. The public cannot download certain data
bases and physical items from the docket but may request these items by
contacting the docket office at 202-566-1744. The docket office has 10
business days to respond to such requests. With the exception of such
material, publicly available docket materials are available
electronically at regulations.gov.
Written Comments. Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2024-0392, 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 to EPA's docket at https://www.regulations.gov any information
you consider to be CBI or other information for which disclosure is
restricted by statute. This type of information should be submitted as
discussed in the Submitting CBI section of this document.
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
[[Page 59769]]
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.
The https://www.regulations.gov website allows you to submit your
comment anonymously, which means the EPA will not know your identity or
contact information unless you provide it in the body of your comment.
If you send an email comment directly to the EPA without going through
https://www.regulations.gov, your email address will be automatically
captured and included as part of the comment that is placed in the
public docket and made available on the internet. If you submit an
electronic comment, the EPA recommends that you include your name and
other contact information in the body of your comment and with any
digital storage media you submit. If the EPA cannot read your comment
due to technical difficulties and cannot contact you for clarification,
the EPA may not be able to consider your comment. Electronic files
should not include special characters or any form of encryption and be
free of any defects or viruses. For additional information about the
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
Submitting CBI. Do not submit information containing CBI to the EPA
through https://www.regulations.gov. Clearly mark the part, or all, of
the information that you claim to be CBI. For CBI information on any
digital storage media that you mail to the EPA, note the docket ID,
mark the outside of the digital storage media as CBI, and identify
electronically within the digital storage media the specific
information that is claimed as CBI. In addition to one complete version
of the comments that includes information claimed as CBI, you must
submit a copy of the comments that does not contain the information
claimed as CBI directly to the public docket through the procedures
outlined in the Written Comments section of this document. If you
submit any digital storage media that does not contain CBI, mark the
outside of the digital storage media clearly that it does not contain
CBI and note the docket ID. Information not marked as CBI will be
included in the public docket and the EPA's electronic public docket
without prior notice. Information marked as CBI will not be disclosed
except in accordance with procedures set forth in 40 CFR part 2.
Our preferred method to receive CBI is transmitted electronically
using email attachments, File Transfer Protocol (FTP), or other online
file sharing services (e.g., Dropbox, OneDrive, Google Drive).
Electronic submissions must be transmitted directly to the OAQPS CBI
Office at the email address [email protected] and, as described above,
should include clear CBI markings and note the docket ID. If assistance
is needed with submitting large electronic files that exceed the file
size limit for email attachments, and if you do not have your own file
sharing service, please email [email protected] to request a file
transfer link. If sending CBI information through the postal service,
please send it to the following address: OAQPS Document Control Officer
(C404-02), OAQPS, U.S. Environmental Protection Agency, 109 T.W.
Alexander Drive, P.O. Box 12055 RTP, North Carolina 27711, Attention
Docket ID No. EPA-HQ-OAR-2024-0392. The mailed CBI material should be
double wrapped and clearly marked. Any CBI markings should not show
through the outer envelope.
Preamble acronyms and abbreviations. Throughout this document, the
use of ``Agency,'' ``we,'' ``us,'' or ``our'' refers to the EPA. We use
multiple acronyms and terms in this preamble. While this list may not
be exhaustive, to ease the reading of this preamble and for reference
purposes, the EPA defines the following terms and acronyms here:
2-BEB 2-Butoxyethyl benzoate
AERMOD American Meteorological Society/EPA Regulatory Model
BAA Butoxyacetic acid
CAA Clean Air Act
CBI Confidential Business Information
CFR Code of Federal Regulations
EFAST Exposure and Fate Assessment Screening Tool
EPA Environmental Protection Agency
FDA Food and Drug Administration
GLP Good Laboratory Practice
HAP hazardous air pollutant(s)
HED human equivalent dose
HEM human exposure model
HQ hazard quotient
IRIS Integrated Risk Information System
ISC3 Industrial Source Complex 3
kg/yr kilograms per year
lbs/yr pounds per year
LOAEL lowest-observed-adverse-effect level
mg/kg milligram per kilogram
NOAEL no-observed-adverse-effect level
NESHAP national emission standards for hazardous air pollutants
OMB Office of Management and Budget
OPPT Office of Pollution Prevention and Toxics
PNEC predicted no-effect concentration
ppm parts per million
PRA Paperwork Reduction Act
REL California Reference Exposure Level
RfC Reference Concentration
RfD oral reference dose
tpy tons per year
UMRA Unfunded Mandates Reform Act
VOC volatile organic compound
Table of Contents
I. Background
A. Where can I get a copy of this document and other related
information?
B. What is the HAP list?
C. What is the authority to modify the HAP list?
D. What is the process for delisting a HAP?
E. What is the history of the 2-BEB delisting process?
II. Summary of the Petition
A. Overview
B. Inhalation Exposure Assessment
C. Human Health Effects Assessment
D. Risk Characterization and Conclusions Regarding Risks to
Human Health
E. Ecological Assessment and Conclusions
III. EPA Analysis of the Petition
A. Overview
B. Inhalation Exposure Assessment
C. Oral and Dermal Exposure
D. Human Health Effects of 2-BEB
E. Human Health Risk Characterization and Conclusions
F. Ecological Risk Characterization and Conclusions
G. Conclusions
IV. Proposed Amendments to 40 CFR Part 63, Subpart C
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
B. Executive Order 14192: Unleashing Prosperity Through
Deregulation
C. Paperwork Reduction Act (PRA)
D. Regulatory Flexibility Act (RFA)
E. Unfunded Mandates Reform Act (UMRA)
F. Executive Order 13132: Federalism
G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
H. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
J. National Technology Transfer and Advancement Act (NTTAA)
I. Background
A. Where can I get a copy of this document and other related
information?
In addition to being available in the docket, an electronic copy of
this action is available on the internet. Following signature by the
EPA Administrator, the EPA will post a copy of this proposed action at
https://www.epa.gov/haps/deletion-2-butoxyethyl-benzoate-2-beb-glycol-
ethers-category-clean-air-act-list-
[[Page 59770]]
hazardous-air. Following publication in the Federal Register, the EPA
will post the Federal Register version of the proposal and key
technical documents at this same website. In accordance with 5 U.S.C.
553(b)(4), a brief summary of this rule may be found at https://www.regulations.gov, Docket ID No. EPA-HQ-OAR-2024-0392.
A memorandum showing the edits that would be necessary to
incorporate the changes to 40 CFR part 63, subpart C proposed in this
action is available in the docket (Docket ID No. EPA-HQ-OAR-2024-0392).
The EPA also will post a copy of this document to https://www.epa.gov/haps/deletion-2-butoxyethyl-benzoate-2-beb-glycol-ethers-category-clean-air-act-list-hazardous-air.
B. What is the HAP list?
In this section, the EPA provides a brief overview of the list of
HAP subject to regulation under CAA section 112 (``the HAP list''), the
Agency's process for considering petitions to modify the HAP list by
adding or deleting a substance, and information about 2-BEB, CAS No.
5451-76-3.
The HAP list is a list of organic and inorganic substances that
have been identified as HAP to be regulated under CAA section 112. The
initial HAP list, which can be found in CAA section 112(b)(1), was
established by Congress in the 1990 amendments to the CAA. The
substances listed as HAP have been associated with a wide variety of
adverse health effects, including cancer, neurological effects,
reproductive effects, and developmental effects. The health effects
associated with various HAP differ depending on the toxicity of the
specific HAP and the circumstances of exposure, such as the amount of
the substance present, the length of time a person is exposed, and the
stage of life at which the person is exposed. CAA section 112(c)
directs the EPA to first identify and list source categories that emit
HAP, then set emission standards for those listed source categories
under CAA section 112(d). Standards promulgated under CAA section
112(d) are commonly referred to as National Emission Standards for
Hazardous Air Pollutants (NESHAP).
C. What is the authority to modify the HAP list?
CAA section 112(b)(3)(A) specifies that any person may petition the
Administrator to modify the HAP list by adding or deleting a
substance.\1\ The Administrator must grant or deny a petition to delete
a HAP within 18 months. CAA section 112(b)(3)(C) and (D) sets out the
substantive criteria for granting a petition to delete a HAP from the
HAP list.\2\ Petitions should include sufficient information to support
the requested deletion of a HAP.
---------------------------------------------------------------------------
\1\ 42 U.S.C. 7412(b)(3)(A).
\2\ 42 U.S.C. 7412(b)(3)(C)-(D).
---------------------------------------------------------------------------
To grant a petition to delete a substance from the HAP list, CAA
section 112(b)(3)(C) provides that the Administrator must determine
that ``there is adequate data on the health and environmental effects
of the substance to determine that emissions, ambient concentrations,
bioaccumulation, or deposition of the substance may not reasonably be
anticipated to cause any adverse effects to the human health or adverse
environmental effects.'' \3\ CAA section 112(a)(7) defines an ``adverse
environmental effect'' as ``[a]ny significant and widespread adverse
effect, which may reasonably be anticipated, to wildlife, aquatic life,
or other natural resources, including adverse impacts on populations of
endangered or threatened species or significant degradation of
environmental quality over broad areas.'' \4\
---------------------------------------------------------------------------
\3\ 42 U.S.C. 7412(b)(3)(C).
\4\ 42 U.S.C. 7412(a)(7).
---------------------------------------------------------------------------
The EPA has long explained that CAA section 112(b)(3)(C) does not
require absolute certainty that a pollutant will not cause adverse
effects on human health or the environment before it may be deleted
from the list.\5\ The use of the terms ``adequate'' and ``reasonably''
in CAA section 112(b)(3)(C) indicate that the EPA must weigh the
potential uncertainties and likely significance of any projections,
assessments, and estimations. Uncertainties concerning the risks of
adverse health or environmental effects may be mitigated if it is shown
that projected exposures are sufficiently low in relation to levels
where adverse effects may occur, thus providing reasonable assurance
that such adverse effects will not occur. Similarly, uncertainties
concerning the magnitude of projected exposures may be mitigated if it
is demonstrated that the levels that might cause adverse health or
environmental effects are sufficiently high to provide reasonable
assurance that exposures will not reach harmful levels.
---------------------------------------------------------------------------
\5\ 70 FR 75047, 75048, Dec. 19, 2005 (final rule delisting
methyl ethyl ketone as a HAP); 69 FR 69320, 69321, Nov. 29, 2004
(final rule delisting ethylene glycol monobutyl ether as a HAP).
---------------------------------------------------------------------------
The EPA further posited that questions as to whether HAP emissions
present adverse health and environmental effects, and questions
regarding the kinds of effects that can come from exposure to those
emissions, may, in certain instances, border on the frontiers of
scientific knowledge and involve limited or inconsistent data. For
example, there could be limited scientific knowledge of the effects of
pollutant exposure on human health or the environment. There could also
be limited emissions data from the relevant source category. Further,
some pollutants have no known safe level of exposure. CAA section
112(b)(3)(C) does not require the Administrator to base his
determination to grant a delisting petition solely on a single
parameter or measure; therefore, the EPA's historical view has been
that the Administrator has the discretion to weigh various factors or
data differently.\6\ The Administrator's decision to delist (or to deny
a petition to delist) a HAP is made on a case-by-case basis and
involves a thorough and comprehensive review of factual issues,
scientific evidence, and data provided in support of a delisting
petition. The EPA has also long explained that CAA section 112(b)(3)(C)
allows the Administrator to balance the likelihood of adverse health
effects against the limits of available scientific data and to exercise
informed judgement in making decisions considering uncertainties in
scientific data. Any projections, assessments, and estimations by a
petitioner must thus be reasonable and not based on conjecture. In sum,
the CAA does not call for certitude of harm but rather accords the
Administrator discretion and flexibility in taking action that is
protective of public health and the environment, including by
considering and balancing factors and relevant policy concerns.
---------------------------------------------------------------------------
\6\ Nat'l Lime Ass'n v. EPA, 627 F.2d 416, 454 n.143 (D.C. Cir.
1980) (``Where a statute is precautionary in nature, the evidence
difficult to come by, uncertain, or conflicting because it is on the
frontiers of scientific knowledge, the regulations designed to
protect the public health, and the decision that of an expert
administrator, we will not demand rigorous step-by-step proof of
cause and effect. Such proof may be impossible to obtain if the
precautionary purpose of the statute is to be served.'') (citing
Ethyl Corp. v. EPA, 541 F.2d 1, 28-29 (D.C. Cir. 1976)); See also
Baltimore Gas & Elec. Co. v. NRDC, 462 U.S. 87, 103 (1983).
---------------------------------------------------------------------------
If the Administrator decides to deny a petition, the EPA publishes
a written explanation of the basis for denial in the Federal Register.
A decision to deny a petition is a final Agency action subject to
judicial review in the U.S. Court of Appeals for the District of
Columbia Circuit under CAA section 307(b). If the Administrator decides
to grant a petition, the EPA publishes a written explanation of the
decision in a proposed rule to delete the substance from the HAP list
codified in 40 CFR part 63, subpart C as we are doing here.
[[Page 59771]]
D. What is the process for delisting a HAP?
In this section, the EPA describes the Agency's historical process
for considering petitions to delist a HAP from the HAP list and what
process the EPA is following for the petition to delist 2-BEB.
A petition to delist a HAP is a formal request to the EPA from an
individual or group to remove a substance from the HAP list. Removal
from the HAP list means the substance is no longer subject to the
regulatory provisions of CAA section 112 and related statutory
provisions governing HAP. CAA section 112(b)(3)(A) requires the
Administrator to either grant or deny a petition by publishing a
written explanation of the reasons for the Administrator's decision.
CAA section 112(b)(3)(A) does not specifically require a formal
rulemaking process to either grant or deny a petition to delist a HAP
from the HAP list. Although the delisting action for a listed HAP is
not subject to the rulemaking procedures of CAA section 307(d), for all
previous delisting actions the EPA has published and solicited public
comment on relevant aspects of the Agency's consideration of such a
complete petition in the Federal Register.\7\ Once the EPA grants a
petition to delist a HAP, such deletion is codified into 40 CFR part
63, subpart C.
---------------------------------------------------------------------------
\7\ Am. Forest & Paper Ass'n. v. EPA, 294 F.3d 113, 117 n.3
(D.C. Cir. 2002) (``Section 112(b) does not contemplate a formal
rulemaking and is not among the sections enumerated in section
307(d)(1) (although other subsections of section 112 are included
there.)'') (Petition to delist methanol as a HAP).
---------------------------------------------------------------------------
The EPA's petition review process proceeds in two phases: a
completeness determination and a technical review. During the
completeness determination, the EPA conducts a broad review of the
petition to determine whether all the necessary subject areas are
addressed and whether reasonable information and analyses are presented
for each of these subject areas. During the technical review, the EPA
conducts a thorough scientific review of the complete petition to
determine whether the data, analyses, interpretations, and conclusions
in the petition are appropriate and technically sound. During the
technical review, the EPA also determines whether the petition
satisfies the necessary requirements of CAA section 112(b)(3)(B) or (C)
and adequately supports a decision to either list or delist the HAP.
Under prior EPA practice, once a petition was determined to be
complete, the Agency placed a notice of receipt of a complete petition
in the Federal Register. The Federal Register notice announced a public
comment period on the complete petition and started the technical
review phase of our decision-making process.\8\ Then, during the
technical review of the petition, the EPA considered all comments and
data submitted during the public comment period for the notice of
receipt of a complete petition. Subsequently, the EPA would publish a
document in the Federal Register containing a written explanation of
the basis for the decision to either grant or deny the petition. If the
EPA intended to grant the delisting petition, the Agency would also
propose the addition of regulatory text to 40 CFR part 63, subpart C to
codify the deletion. After consideration of public comments, the EPA
would publish the final decision on the petition in the Federal
Register. If the EPA granted a delisting petition, in a final action
the Agency would amend 40 CFR part 63, subpart C, List of Hazardous Air
Pollutants, Petitions Process, Lesser Quantity Designations, Source
Category List, to codify the deletion of the substance from the HAP
list. Thus, the EPA's prior practice encompassed at least three
publications in the Federal Register.
---------------------------------------------------------------------------
\8\ See, e.g., 70 FR 30407, May 26, 2005 (notice of receipt of a
complete petition to delist 4,4'-methylene diphenyl diisocyanate as
a HAP); 64 FR 42125, Aug. 3, 1999 (notice of receipt of a complete
petition to delist ethylene glycol monobutyl ether as a HAP); 64 FR
38668, July 19, 1999 (notice of receipt of a complete petition to
delist methanol as a HAP); 64 FR 33453, June 23, 1999 (notice of
receipt of a complete petition to delist Methyl Ethyl Ketone as a
HAP).
---------------------------------------------------------------------------
In this action, the EPA is announcing a streamlined approach to
petitions under section CAA 112(b)(3)(B) effective with this petition
to delist 2-BEB. Rather than issuing a Federal Register document
announcing the receipt of a complete petition, the EPA will now inform
the petitioner by letter once a preliminary evaluation determines that
the petition is complete according to Agency criteria.\9\ Subsequently,
once the EPA's technical review is complete, the Agency will publish a
Federal Register document with a written explanation of the basis for
the proposed decision to grant or deny the petition and, if
appropriate, propose the addition of regulatory text to 40 CFR part 63,
subpart C to codify the deletion. After the opportunity for comment and
review of the comments, the EPA will publish in the Federal Register
the final action either granting or denying the petition. If the
petition to delist is granted, 40 CFR part 63, subpart C will be
modified to incorporate the change.
---------------------------------------------------------------------------
\9\ For the petition to delist 2-BEB, we informed the petitioner
of the determination that the petition was complete on Nov. 24,
2021.
---------------------------------------------------------------------------
Additionally, the EPA intends to reorganize 40 CFR part 63, subpart
C to provide clarity and allow space for future amendments. See section
IV. of this preamble for more information on this reorganization.
E. What is the history of the 2-BEB delisting process?
In this section, the EPA provides an overview and information about
the Agency's technical review of the petition to delist 2-BEB.
On September 30, 2019, the Dow Chemical Company (the
``Petitioner'') submitted a petition to delete 2-BEB (CAS No. 5451-76-
3) from the glycol ethers category of the HAP list (the ``Petition'').
2-BEB is a colorless liquid with low odor, a high boiling point (292
[deg]C at 760 millimeters of mercury (mmHg)), and low vapor pressure
(2.09E-04 mmHg at 20 [deg]C). It is miscible in water with moderate
water solubility (106 mg/L at 20 [deg]C). 2-BEB has utility as a
coalescing solvent for water-based, low volatility organic compound
(VOC) coatings. It can also be used as a replacement for phthalate-
based plasticizers in caulking compounds and in some polyvinyl chloride
(PVC) formulations.
Following receipt of the Petition, the EPA conducted a preliminary
evaluation to determine whether the Petition was complete according to
Agency criteria. To be deemed complete, the EPA requires that a
petition consider available data on health and environmental effects of
the substance to be deleted. A petition should also provide
comprehensive emissions data, including peak and annual average
emissions for each known source or for an appropriately selected subset
of sources, and must estimate the resulting exposures to people living
in the vicinity of the sources. In addition, a petition must discuss
the environmental impacts associated with emissions of the substance to
the ambient air and impacts associated with the subsequent cross-media
transport of those emissions.\10\ The EPA determined the Petition to be
incomplete and requested additional information from the Petitioner.
After receiving additional
[[Page 59772]]
submittals from the Petitioner through August 13, 2021, the EPA
determined the Petition to be complete.\11\ The EPA notified the
Petitioner by electronic mail of this determination on November 24,
2021.\12\
---------------------------------------------------------------------------
\10\ E.g., 70 FR 30407, May 26, 2005 (notice of receipt of a
complete petition to delist 44-methylene diphenyl diisocyanate as a
HAP); 64 FR 42125, Aug. 3, 1999 (notice of receipt of a complete
petition to delist ethylene glycol monobutyl ether as a HAP); 64 FR
38668, July 19, 1999 (notice of receipt of a complete petition to
delist methanol as a HAP); 64 FR 33453, June 23, 1999 (notice of
receipt of a complete petition to delist Methyl Ethyl Ketone as a
HAP).
\11\ The complete Petition can be found in the docket, EPA-HQ-
OAR-2024-0392-0003 through EPA-HQ-OAR-2024-0392-0018.
\12\ The email notification can be found in the docket, EPA-HQ-
OAR-2024-0392-0033.
---------------------------------------------------------------------------
Following the completeness determination, the EPA conducted a
preliminary technical review of the Petition. Based on the preliminary
assessment, the EPA had follow-up conversations with the Petitioner in
June 2022 to further clarify certain aspects of the Petition. After
these discussions, the Petitioner submitted additional information in
September 2022.\13\ The Petition and all supplements to the Petition
are available for review in the docket.\14\ The EPA has fully
considered all of the Petitioners' submissions in the technical review
and the determination to propose granting the Petition to delist 2-BEB
from the glycol ethers category in the HAP list.
---------------------------------------------------------------------------
\13\ A summary of this correspondence can be found in the risk
assessment in the docket, EPA-HQ-OAR-2024-0392-0038.
\14\ Docket ID No. EPA-HQ-OAR-2024-0392.
---------------------------------------------------------------------------
II. Summary of the Petition
In this section, the EPA presents the details of the Petition that
includes the exposure assessment, the human health effects assessment,
the Petitioners' risk assessment and methodology and ecological
assessment and conclusions.
A. Overview
The Petition is presented in the form of a risk assessment that
considers multiple routes of exposure and evaluates the likelihood and
severity of adverse effects to human health and the environment arising
from exposures to ambient levels of 2-BEB. Existing literature on the
toxicity and health effects of 2-BEB is sparse. To address this gap,
the Petitioner performed oral, dermal, and inhalation toxicity testing
according to the Organisation for Economic Co-operation and Development
(OECD) guidelines.\15\ The Petitioner also relied on the EPA's 2010
Integrated Risk Information System (IRIS) assessment for ethylene
glycol monobutyl ether (EGBE) as the basis for the human health effects
evaluation of 2-BEB.\16\ The Petitioner further provided a worst-case
inhalation toxicity analysis that used ethylene glycol monomethyl ether
(EGME), which is the most potent chemical with a reference
concentration (RfC) available from the EPA's IRIS assessment program
for the glycol ethers category.\17\ In sum, the Petition characterizes
the sources and releases of 2-BEB, estimates exposures, identifies the
potential hazard and the dose-response relationship of 2-BEB,
characterizes environmental risk, and characterizes the human health
risk from a reasonable worst-case lifetime exposure to 2-BEB and a
reasonable worst-case short-term (24-hour) exposure to 2-BEB.
---------------------------------------------------------------------------
\15\ OECD Guidelines for the Testing of Chemicals, section 4.
Health Effects: https://doi.org/10.1787/20745788.
\16\ U.S. Environmental Protection Agency. (2010). IRIS
Toxicological Review of Ethylene Glycol Mono Butyl Ether (EGBE)
(Final Report), EPA/635/R-08/006F.
\17\ U.S. Environmental Protection Agency. (1991). Integrated
risk information system (IRIS) assessment for 2-Methoxyethanol.
Prepared by the National Center for Environmental Assessment.
---------------------------------------------------------------------------
B. Inhalation Exposure Assessment
1. Air Emissions Estimate
The Petitioner estimated 2-BEB emissions based on nationwide
projected production volume and modeled emissions estimates. In the
Petition, the Petitioner states that, as of September 30, 2019, all 2-
BEB produced domestically has been for export and use outside of the
United States. The Petitioner estimated that about 200,000 pounds (lbs)
(91,000 kilograms (kg)) of 2-BEB were produced in the United States
from 2016 to mid-2019, an average of about 57,000 lbs/yr (26,000 kg/
yr). The Petitioner further stated that 2-BEB is being explored as a
substitute for current components of water-based coatings but is not
currently used or sold in the United States. Additionally, there are no
emissions or monitoring data available that are pertinent to the
domestic manufacture, use, and release of 2-BEB in the United States.
To address the absence of available domestic emissions or
monitoring data for 2-BEB, the Petitioner estimated 2-BEB emissions
based on their projected production volume. To estimate the projected
maximum production volume of 2-BEB, the Petitioner assumed that the
production time would be 48-50 hours per batch and that 2-BEB would be
manufactured in 10 batches. Thus, the approximate production time for
the entire quantity of 2-BEB would range from 480-500 hours. For
processing, it was assumed that 2-BEB would be incorporated into a
water-based paint product and that 265,000 kg/yr would be available for
processing (275,000 kg/yr minus 10,000 kg/yr lost to emissions in
manufacturing). The Petitioner estimated that the projected maximum
production volume of 2-BEB would be about 275,000 kg/yr.
The Petitioner then used the Chemical Screening Tool for Exposure
and Environmental Releases (ChemSTEER) to generate screening-level
emissions estimates for potential releases of 2-BEB into the air and
water from manufacturing and processing. ChemSTEER is a computer-based
software program developed by the EPA's Office of Pollution Prevention
and Toxics (OPPT). ChemSTEER combines multiple mathematical models
(e.g., EPA/OPPT penetration model) and emissions estimation methods
(e.g., AP-42) into one tool that can be used to generate ``screening-
level estimates for environmental releases of and worker exposures to a
chemical manufactured and used in industrial and commercial operations
(i.e., workplaces).'' \18\ ChemSTEER results are considered screening
level because many of the models in ChemSTEER are characterized by the
EPA to be screening-level models. As such, the screening-level results
from ChemSTEER ``are intended to be conservative in that predicted
results are likely to be higher, or at least higher than average, as
compared to actual releases and exposures occurring in the real-world
setting.'' \19\
---------------------------------------------------------------------------
\18\ ChemSTEER Users Guide, May 2015. Available at https://www.epa.gov/sites/default/files/2015-05/documents/user_guide.pdf.
\19\ ChemSTEER Users Guide, May 2015. Available at https://www.epa.gov/sites/default/files/2015-05/documents/user_guide.pdf.
---------------------------------------------------------------------------
To generate screening-level emissions estimates for potential
releases of 2-BEB into the air from manufacturing and processing, the
Petitioner used the following emission points. For manufacturing,
emissions points for 2-BEB included:
Aqueous wash of organic mass.
Distillation column bottoms disposal.
Sampling of liquid product.
Loading of liquid product into drums.
Equipment cleaning losses of liquids from multiple
vessels.
For processing, emissions points for 2-BEB included:
Unloading liquid raw material from drums.
Vapor release from open liquid surfaces.
Sampling liquid product.
Loading liquid product into drums.
Equipment cleaning of liquids from multiple vessels.
Cleaning liquid residuals from drums used to transport raw
material.
[[Page 59773]]
The Petitioner then used the Equilibrium Criterion model to
estimate emissions of 2-BEB from wastewater into the air.\20\ Table 1
summarizes the Petitioner's estimated air emissions of 2-BEB from
manufacturing, processing, and wastewater.
---------------------------------------------------------------------------
\20\ EQC, v 1.0, https://www.trentu.ca/cemc/resources-and-models/eqc-equilibrium-criterion-model.
Table 1--Air Emissions of 2-BEB
------------------------------------------------------------------------
Air emissions (kg/ Air emissions
Source yr) (tpy)
------------------------------------------------------------------------
Manufacturing..................... 2.74E-3 3E-6
Processing........................ 7.65E-1 8E-4
Wastewater........................ 9.73E1 1.07E-1
-------------------------------------
Total......................... 9.8E1 1.1E-1
------------------------------------------------------------------------
2. Modeling of 2-BEB Air Concentrations and Calculation of Noncancer
Hazard Quotient
The Petitioner used the EPA's Exposure and Fate Assessment
Screening Tool (EFAST) to estimate ambient air concentrations of 2-BEB
emitted from manufacturing, processing, and wastewater.\21\ The EFAST
tool uses SCREEN3, a single-source Gaussian plume model that provides
maximum ground-level concentrations for point, area, flare, and volume
sources. The SCREEN3 model is the screening version of the Industrial
Source Complex 3 (ISC3) model.\22\ The SCREEN3 model is listed by the
EPA as an appropriate screening model. As a screening tool, EFAST/
SCREEN3 ``modeled estimates of concentrations and doses are designed to
reasonably overestimate exposures, for use in an exposure assessment in
the absence of or with reliable monitoring data.'' \23\
---------------------------------------------------------------------------
\21\ U.S. Environmental Protection Agency. (2014). E-FAST-
Exposure and Fate Assessment Screening Tool Version 2014: https://www.epa.gov/tsca-screening-tools/e-fast-exposure-and-fate-assessment-screening-tool-version-2014.
\22\ See U.S. Environmental Protection Agency. Air Quality
Dispersion Modeling--Screening Models: https://www.epa.gov/scram/air-quality-dispersion-modeling-screening-models#screen3.
\23\ U.S. Environmental Protection Agency. (2014). E-FAST-
Exposure and Fate Assessment Screening Tool Version 2014: https://www.epa.gov/tsca-screening-tools/e-fast-exposure-and-fate-assessment-screening-tool-version-2014.
---------------------------------------------------------------------------
The Petitioner conducted air concentration modeling using the air
emissions of 2-BEB that are presented in table 1 and assumed that the
mass of 2-BEB is released as fugitive emissions (using the following
fugitive release parameters for manufacturing/processing--a 3 meter (m)
release height from the ground and a release area that is 10 m in
length and 10 m in width; using the following fugitive release
parameters for wastewater--a 3 m release height from the ground and a
release area that is 10,000 m in length and 10,000 m in width) with no
emission control technologies in operation. Table 2 presents the
maximum 24-hour and annual average 2-BEB inhalation exposure
concentrations in milligram per cubic meter (mg/m\3\) that resulted
from the Petitioner's analysis.
Table 2--Petitioner's Modeled Inhalation Exposure Concentrations for 2-
BEB by Source
------------------------------------------------------------------------
Max 24 hour air Max annual air
Source concentration (mg/ concentration (mg/
m\3\) m\3\)
------------------------------------------------------------------------
Manufacturing..................... 1.82E-5 7.98E-8
Processing........................ 3.98E-4 2.18E-5
Wastewater........................ 2.61E-6 2.08E-7
------------------------------------------------------------------------
C. Human Health Effects Assessment
The Petitioner claimed that 2-BEB is rapidly metabolized in vivo to
form EGBE (CAS No. 111-76-2) and benzoic acid (CAS No. 65-85-0) in both
animals and humans. The EPA has previously modified the HAP list by
removing EGBE from the glycol ethers category.\24\ To address the
sparse literature on the toxicity and health effects of 2-BEB, the
Petitioner performed oral, dermal, and inhalation toxicity testing
according to OECD guidelines. The Petitioner used subchronic oral
toxicity data for 2-BEB consistent with OECD Guideline 408 (1998) \25\
and the 2010 IRIS assessment for EGBE \26\ as the basis for their human
health effects evaluation of 2-BEB. The Petitioner also provided a
worst-case inhalation toxicity analysis using EGME, which is the most
potent chemical with a RfC available for the glycol ethers
category.\27\
---------------------------------------------------------------------------
\24\ 69 FR 69320, Nov. 29, 2004.
\25\ OECD. (2018). Test No. 408: Repeated Dose 90-Day Oral
Toxicity Study in Rodents, OECD Guidelines for the Testing of
Chemicals, section 4, OECD Publishing: https://doi.org/10.1787/9789264070707-en.
\26\ U.S. Environmental Protection Agency. (2010). IRIS
Toxicological Review of Ethylene Glycol Mono Butyl Ether (EGBE)
(Final Report), EPA/635/R-08/006F, 2010. Available at https://www.epa.gov/iris and in the docket for this action.
\27\ U.S. Environmental Protection Agency. (1991). Integrated
risk information system (IRIS) assessment for 2-Methoxyethanol.
Prepared by the National Center for Environmental Assessment.
Available at https://www.epa.gov/iris and in the docket for this
action.
---------------------------------------------------------------------------
To evaluate the potential for acute inhalation toxicity, the
Petitioner provided inhalation studies that were performed using
aerosolized 2-BEB. Male and female F344/DuCrl rats were exposed via a
nose-only exposure system for four hours to chamber concentrations of
3.71 or 5.39 mg 2-BEB per liter (L) (these exposure concentrations were
significantly higher than the estimated ambient concentrations in table
2). The rats were observed for 14 days post-exposure. Clinical
observations of soiling on various parts of the body were made;
however, this effect was resolved by day seven. All treated groups had
mean body weight losses on day two, with recovery to pre-exposure
levels by day eight. There were no gross pathological abnormalities
detected at necropsy.
[[Page 59774]]
To compensate for the lack of 2-BEB vapor inhalation data, the
Petitioner relied on the chronic inhalation data for EGBE to estimate
the chronic risk of 2-BEB exposure to human health. EGBE is one of the
two rapidly generated metabolites for 2-BEB, which the EPA has
previously delisted from the glycol ethers category,\28\ The Petitioner
also provided a route-to-route extrapolation based on 2-BEB oral
toxicity data for comparison. To address the uncertainty associated
with estimates that are either not chemical or route specific, the
Petitioner also performed a worst-case toxicity analysis for EGME, the
most potent chemical for the glycol ethers category with a RfC.
---------------------------------------------------------------------------
\28\ 69 FR 69320, Nov. 29, 2004.
---------------------------------------------------------------------------
The Petitioner conducted acute and subchronic oral toxicity studies
according to OECD guidelines. These studies served to help characterize
the hazards from oral exposure to 2-BEB and to estimate a screening
oral reference dose (RfD) value for 2-BEB exposure. Additionally, the
Petitioner conducted an acute dermal exposure study. The study details
and results can be found in Attachment A-1 and Attachments 1-12 of the
Petition and are available in the docket for this action.
In the acute oral study, the Petitioner estimated the median lethal
dose (LD50) value to be 940 mg/kg in female Wistar rats. In mice dosed
with 2000 mg/kg, adverse effects or abnormal findings were observed in
the kidney, urinary bladder, stomach glandular mucosa, and liver. Mice
dosed at 550 mg/kg showed no abnormal clinical signs. In the dermal
study, female and male Wistar rats were exposed at 2000 mg/kg with no
clinical signs of toxicity, skin reactions, or mortality under the 14-
day observation period.
The Petitioner submitted a 28-day study on the reproductive
toxicity of 2-BEB via oral exposure. The study, published by Johnson et
al., 2016 was conducted in groups of 12 male and 12 female Crl:CD(SD)
rats fed either 0, 500, 1,500, or 5,000 parts per million (ppm) of 2-
BEB.\29\ For both female and male rats, dosing began two weeks before
breeding. For females, dosing continued until postpartum day four and
for male rats until test day 36. Over the course of the study, dams
(pregnant rats) were monitored for clinical observations, body weight
gain, and feed consumption. At necropsy, dams were evaluated for gross
pathologic lesions, organ weights (liver, kidney, spleen, uterine),
hematological effects, number of corpora lutea, uterine implantations,
resorptions, and live/dead fetuses. The fetuses were weighed, sexed,
and evaluated for external alterations or skeletal abnormalities. No
treatment-related effects on reproductive function or pre-natal/early
neonatal growth and survival in the offspring were observed at any dose
level. At 5,000 ppm, decreased feed consumption and body weight,
increased spleen weight, and regenerative anemia were observed in
female rats. Females given 5,000 ppm also had a treatment-related
higher platelet count, which may occur in association with
reticulocytosis. Higher mean urea nitrogen, triglyceride, creatinine,
and phosphorus concentrations were found in female rats in the 5,000-
ppm treatment group. No adverse effects were observed in the females
given 500 or 1,500 ppm or in males at any dose level.
---------------------------------------------------------------------------
\29\ Johnson, K.J. et al. (2016). 2-Butoxyethyl Benzoate: A
Combined Dietary Toxicity Study with the Reproduction/Developmental
Toxicity Screening Test in Crl:CD(SD) Rats. Report of Toxicology and
Environmental Research And Consulting, The Dow Chemical Company.
---------------------------------------------------------------------------
The Petitioner also submitted a subchronic oral toxicity study.\30\
The study was performed in compliance with Good Laboratory Practice
(GLP) and OECD guidelines. The dose selections were informed by a
previously conducted range-finding study published by Johnson et al.,
2015.\31\ Ten male and ten female rats per treatment group consumed
food containing 0, 500, 1,500, or 5,000 ppm of 2-BEB for at least 90
days. These diets resulted in time-weighted average doses of 0, 28.9,
88.1, or 285 mg/kg/day for males and 0, 32.6, 94.9, or 310 mg/kg/day
for females, respectively. The Petitioner reported daily cage-side
observations, weekly detailed clinical observations, ophthalmic
examinations, body weights/body weight gains, feed consumption,
hematology, prothrombin time, clinical chemistry, urinalysis, selected
organ weights, and gross and histopathologic examinations. No 2-BEB-
related effects on clinical signs, ophthalmic, hematology, prothrombin
time, urinalysis parameters, organ weight, or gross or histopathologic
observations were observed. At the highest dose (5,000 ppm), female
rats showed a decrease in body weight gain and feed consumption. At the
same dose, male rats demonstrated a statistically significant reduction
in serum sodium levels. No effects were observed at the doses below
5,000 ppm. The Petitioner selected a no-observed-adverse-effect level
(NOAEL) of 1,500 ppm based on decreases in body weight gain and feed
consumption in females.
---------------------------------------------------------------------------
\30\ 2-Butoxyethyl Benzoate: 90-Day Dietary Toxicity Study in
Crl:CD(SD) Rats, which is available in the docket for this action in
the document Attachment A-1.
\31\ Johnson, K.J. et al. (2015). 2-Butoxyethyl Benzoate:
Dietary Range-Finding Study in Crl:CD(SD) Rats. Report of Toxicology
and Environmental Research And Consulting, The Dow Chemical Company.
---------------------------------------------------------------------------
The NOAEL was identified as 1,500 ppm because this was the highest
dose administered to rats that did not result in any measurable adverse
effects. In the 90-day oral toxicity study, the 5,000-ppm dose reduced
body weight and food consumption in female rats. The Petitioner
estimated the NOAEL to be equivalent to roughly 100 mg/kg/day in rats.
The Petitioner chose not to convert the rat dose to a human equivalent
dose (HED), citing species differences in the rate of formation of, and
sensitivity to, the butoxyacetic acid (BAA) metabolite of EGBE, which
is linked to hemolytic toxicity. The Petitioner applied a cumulative
uncertainty factor (UF) of 90 to account for extrapolation from the
subchronic to a chronic exposure duration (UFS = 1),
extrapolation from a lowest-observed-adverse-effect level (LOAEL) to a
NOAEL (UFL = 1), variation in sensitivity within the human
population (UFH = 10), variation in sensitivity from animals
to humans (UFA = 3), and gaps in the database
(UFD = 3). The Petitioner's selection of uncertainty factors
assumed that 2-BEB toxicity is driven solely by the EGBE/BAA
metabolites, resulting in an estimated RfD of 1.1 mg/kg/day based on 2-
BEB oral toxicity data.
The Petitioner selected the UFH of 10 to match the
UFH used in the EGBE RfD determination and account for the
potential for some individuals to have altered metabolism, excretion,
or susceptibility to hemolytic toxicity of the BAA metabolite. The
Petitioner selected the UFA of 3 for toxicokinetics due to
the absence of a physiologically based pharmacokinetic (PBPK) model for
2-BEB to account for species differences between the rats and humans. A
value of 1 was selected by the Petitioner for the toxicodynamic portion
citing several studies that have been performed indicating that humans
are significantly less susceptible than rats to the hemolytic effects
of BAA.32 33 34 35 The Petitioner also
[[Page 59775]]
selected the UFD of 3 because 2-BEB lacks a chronic study
and subchronic studies in a second species. The Petitioner did not
select the UFD of 10 because of the available data on the 2-
BEB metabolites, EGBE and benzoic acid. The Petitioner determined that
the UFS of 1 is sufficient because the effect used as the
basis of their RfD, hemolysis, does not increase with longer exposure.
The Petitioner also determined that the UFL of 1 is
sufficient because the RfD was derived using a NOAEL.
---------------------------------------------------------------------------
\32\ Carpenter CP, Pozzani MS, Weil CS, Nair JH, Keck GA, Smyth
HF (1956). The toxicity of butyl CELLOSOLVETM solvent.
Arch Ind Hlth, 14, -114-31.
\33\ Ghanayem BI and Sullivan CA (1993). Assessment of the
haemolitic activity of 2-butoxyethanol and its major metabolite,
butoxyacetic acid, in various mammals including humans. Human & Exp.
Toxicol., 12, 305-311.
\34\ Udden MM (2000). Rat erythrocyte morphological changes
after gavage dosing with 2-butoxyethanol: a comparison with the in
vitro effects of butoxyacetic acid on rat and human erythrocytes. J.
Appl. Toxicol., 20, 381-387.
\35\ Udden MM and Patton CS (1994). Hemolysis and deformability
of erythrocytes exposed to butoxyacetic acid, a metabolite of 2-
butoxyethanol: sensitivity in rats and resistance in normal humans.
J. Applied Toxicol., 14(2), 91-96.
---------------------------------------------------------------------------
The Petitioner provided the following reports on the methods and
results of three key in vitro GLP-studies to assess 2-BEB's potential
for genotoxicity: a Bacterial Reverse Mutation Assay (OECD Guideline
471), an In Vitro Mammalian Cell Gene Mutation Test (OECD Guideline
476), and an In Vitro Mammalian Chromosome Aberration Test (OECD
Guideline 473). In addition, the Petitioner provided the results of a
Mammalian Erythrocyte Micronucleus Test (OECD Guideline 474).\36\ For
genotoxicity, 2-BEB tested negative both with and without metabolic
activation for all three in vitro genotoxicity assays and likewise
tested negative in the in vivo micronucleus test assay.
---------------------------------------------------------------------------
\36\ The detailed methods and results are available in the
docket for this action in the document Attachments 1-12.
---------------------------------------------------------------------------
D. Risk Characterization and Conclusions Regarding Risks to Human
Health
There is currently no RfC for 2-BEB. Therefore, to calculate a
conservative noncancer hazard quotient (HQ) for inhalation exposure to
2-BEB, the Petitioner used the most conservative RfC value associated
with a member of the glycol ethers category as a surrogate, namely,
EGME.\37\ According to the IRIS, the RfC for EGME is 0.02 mg/m\3\. The
Petitioner divided the concentrations in table 2 of this preamble by
the RfC for EGME to calculate a conservative noncancer HQ for 2-BEB.
Table 3 presents the resulting HQs by emissions source.
---------------------------------------------------------------------------
\37\ See documents ``EGME_Worst-case-toxicity-9-8-22'' and
``Revised_Tables11and12'' in the docket for details.
Table 3--Noncancer Hazard Quotients Using 2-BEB Exposures and EGME RfC
------------------------------------------------------------------------
Source Max 24 hour HQ Max annual HQ
------------------------------------------------------------------------
Manufacturing........................... 9.1E-4 3.99E-6
Processing.............................. 1.99E-2 1.09E-3
Wastewater.............................. 1.31E-4 1.04E-5
-------------------------------
Total............................... 2E-2 1.1E-3
------------------------------------------------------------------------
The Petitioner concluded that despite the conservative assumptions
and large production volumes, all HQs are substantially below 1,
indicating low to minimal risk for human inhalation exposures. For
ingestion and dermal exposures, the Petitioner summarized various HQs
estimated in table 17 of the Petition, which is available in the docket
for this action.
E. Ecological Assessment and Conclusions
The Petitioner conducted an aquatic and terrestrial ecological risk
assessment to evalute the potential for adverse environmental effects
from 2-BEB. The Petitioner estimated a water-concentration benchmark
that should be protective of aquatic life as a predicted no-effect
concentration (PNEC) value considering invertebrates, fish, and algae.
For terrestrial PNECs, the Petitioner evaluated earthworms and plants.
Sediments were excluded from the Petitioner's analysis because the
fugacity modeling predicted minor partitioning to sediments.
The Petitioner conducted ecotoxicity tests for aquatic biota using
the the appropriate OPPT guideline.\38\ The Petitioner also conducted
acute and chronic fish and invertebrat, toxicity tests along with algal
tests for 2-BEB in surface water using appropriate EPA/OECD guidelines.
The Petitioner further conducted earthworm and seedling emergence tests
on 2-BEB in soils using appropriate guidelines. Based on those tests,
which also fulfill the EPA OPPT minimum data set requirement, the
Petitioner calculated an aquatic PNEC of 0.00659 mg/L water and a soil
PNEC of 2.5 mg/kg dry weight (dw) soil. To estimate environmental
risks, the Petitioner used the HQ approach, as described in section
II.D. of this preamble. In this case, the HQ compares the estimated
exposure level in the environment to the calculated PNEC.
---------------------------------------------------------------------------
\38\ Summarized in table 2, p. 9, of Attachment 2 of the
Petition.
---------------------------------------------------------------------------
III. EPA Analysis of the Petition
In this section, the EPA provides an overview of the Agency's
substantive and technical review of the Petition. In section III.A.,
the EPA presents the details of the Agency's review of 2-BEB. In
section III.B., the EPA presents the Agency's review of the inhalation
exposure assessment for 2-BEB, which includes the Petitioner's estimate
of emissions of 2-BEB, modeling of 2-BEB air concentrations, and
calculation of noncancer HQs. In section III.C., the EPA discusses the
Agency's review of oral and dermal exposure of 2-BEB. In section
III.D., the EPA discusses the Agency's review of human health effects
of 2-BEB. In section III.E., the EPA presents the review of human
health risk characterization for 2-BEB and relevant conclusions. In
section III.F., the EPA presents the review of ecological risk
characterization for 2-BEB.
The EPA's substantive review of the Petition described in this
section indicates that the Petitioner has provided sufficient
information to support the requested deletion of 2-BEB under the
substantive criteria set forth in CAA section 112(b)(3)(C) and (D).
Therefore, the EPA is determining that there are adequate data on the
potential health and environmental effects of 2-BEB and further
determining that emissions, ambient concentrations, bioaccumulation, or
deposition of 2-BEB may not reasonably be anticipated to cause any
adverse human health or environmental effects.
A. Overview
2-BEB falls within the CAA section 112(b)(1) definition of the
glycol ether category, which is a listed HAP as
[[Page 59776]]
redefined by 40 CFR part 63, subpart C. It is a colorless liquid with
low odor, a high boiling point (292 [deg]C at 760 mmHg), and low vapor
pressure (2.09E-04 mmHg at 20 [deg]C). It is miscible in water with
moderate water solubility (106 mg/L at 20 [deg]C). Additionally, 2-BEB
has utility as a coalescing solvent for water-based, low VOC coatings.
It can also be used as a replacement for phthalate-based plasticizers
in caulking compounds and in some PVC formulations.
The Petition states that 2-BEB released to the air has a
degradation half-life of 11.8 hours with an overall environmental
persistence of 21.6 hours. The EPA evaluated the predicted half-life of
2-BEB in air and found these values to be reasonable.
Based on the EPA's review of the available information on 2-BEB,
the Agency has concluded that inhalation and ingestion are the
important routes of nonoccupational exposures that would result from 2-
BEB emissions, and we have considered these two routes of exposure as
well as some dermal exposures in evaluating the Petition.
B. Inhalation Exposure Assessment
1. Air Emissions Estimate
As a first step in evaluating the Petitioner's inhalation risk
assessment, the EPA reviewed the Petitioner's estimate of emissions of
2-BEB upon which the Petitioner based the exposure modeling. Upon
review, the EPA determined the Petitioner appropriately identified the
potential sources of 2-BEB air emissions from manufacturing,
processing, and wastewater. The quantities of 2-BEB that the Petitioner
assumed to be manufactured and processed, which are presented in
section II.B.1. of this preamble, were reasonable maximum values that
provided conservatively high emissions estimates. Specifically, the
Petitioner indicated that, on average, 57,000 lbs/yr (26,000 kg/yr) of
2-BEB were produced from 2016 to mid-2019. The Petitioner estimated
that their maximum production would be 600,000 lbs/yr (275,000 kg/yr),
which is more than 10 times current production. The EPA welcomes
comment on this production assumption to ensure that it is reasonable
and conservative. The Petitioner indicated in its June 29, 2021, letter
that ``based on its current understanding of production potential, the
petitioner adhered to the 275,000 kg/year figure for projected future
growth and/or new product applications related to future delisting.''
\39\ In the same letter, the Petitioner clarified that a previously
mentioned production estimate of 5,000,000 lbs/yr (2.286,000 kg/yr),
which was presented as a ``high-end wishful thinking estimate,'' was
deemed to be ``unrealistic'' given the Petitioner's current knowledge
of the potential customer base. The EPA also finds that the model
inputs, assumptions, analysis, and methods used by the Petitioner to
estimate 2-BEB air emissions are appropriate and provide reasonably
conservative screening-level estimates of 2-BEB emissions and exposure
estimates.\40\
---------------------------------------------------------------------------
\39\ This letter can be found in the docket, EPA-HQ-OAR-2024-
0392-0038.
\40\ Note, as described in section III.B.2. of this preamble,
the EPA conducted the chronic noncancer inhalation risk screening
analysis using both the ``maximum'' production volume estimate of
275,000 kg/yr and the ``high end--unrealistic'' production volume
estimate of 2,300,000 kg/yr, which is over 8 times higher than the
``maximum'' value. In the EPA's screening analysis, the acute
noncancer risks were below levels of concern using either production
value.
---------------------------------------------------------------------------
2. Modeling of 2-BEB Air Concentrations and Calculation of Noncancer
Hazard Quotient
The Petitioner performed the inhalation exposure assessment using
the screening models discussed in section II.B. of this preamble. The
Petitioner stated that a high level of conservatism was built into
deriving 2-BEB exposure estimates. The conservative assumptions built
into the analysis include:
Assumed open-top mixing and processing of 2-BEB during
incorporation into water-based paints. Traditionally, this is a closed-
unit operation, but for this worst-case assumption, the process is
assumed to be an open process.
Assumed any release of 2-BEB into water does not undergo
any treatment at Publicly Owned Treatment Works (POTWs).
Assumed all emissions during both manufacturing and
processing are uncontrolled, such as when a thermal oxidizer is
utilized.
Assumed emissions to be fugitive emissions and not point
or stack sources. Stack or point emissions usually result in lower
ambient ground-level concentrations compared with fugitive emissions
modeling.
Assumed that a person exposed to 2-BEB lives in the
vicinity where the chemical is both manufactured and processed.
Used theoretical maximum production values of 2-BEB for
emissions calculations and modeling. (Performed the screen using both
the ``Maximum'' estimate of 275,000 kg/yr and the ``High End--
Unrealistic'' estimate of 2,300,000 kg/yr).
The EPA has determined that the Petitioner performed the dispersion
modeling analysis following appropriate modeling guidance for a
screening assessment. To verify the Petitioner's results, the EPA
conducted a screening assessment of the Petitioner's 2-BEB emissions
estimates using a Human Exposure Model (HEM) screening tool that uses
data from American Meteorological Society/EPA Regulatory Model
(AERMOD).\41\ These assumptions included:
---------------------------------------------------------------------------
\41\ U.S. Environmental Protection Agency. AERMOD Modeling
System Development: https://www.epa.gov/scram/aermod-modeling-system-development.
---------------------------------------------------------------------------
Assumption of fugitive/ground level emissions (1 m release
height, 10 m length, 10 m width).
100 m to the nearest residence.
100 m to the fenceline.
10x acute factor for releases directly to air, 1x acute
factor for releases from water.
Using the ``maximum'' production volume estimate of 275,000 kg/yr,
the EPA's screening assessment shows that the highest predicted maximum
annual average off-site (i.e., beyond the fenceline, which was assumed
to be 100 m from the emissions source) concentration of 2-BEB would be
7E-4 mg/m\3\. This concentration is approximately one order of
magnitude higher than the highest concentration estimated by the
Petitioner of 2.2E-5 mg/m\3\. The primary reason the EPA's screen
resulted in a higher concentration is that the Agency used much more
conservative fugitive release parameters, particularly for the fugitive
release from water. The chronic noncancer HQ for 2-BEB, which was
calculated by dividing the maximum annual concentration of 2-BEB from
the EPA's conservative screening analysis by the RfC for EGME (chronic
noncancer HQ = 7E-4 mg/m\3\ divided by 0.02 mg/m\3\) is 3.6E-2. This is
approximately one order of magnitude higher than the HQ estimated by
the Petitioner of 1.1E-3. The primary reason the EPA's screen resulted
in a higher concentration is that the Agency used much more
conservative fugitive release parameters. Regardless, both the
Petitioner's and the EPA's assessments result in an HQ value for 2-BEB
that is well below 1, which indicates that chronic noncancer risk is
below levels of concern. Even using the ``high end--unrealistic''
production volume estimate of 2,300,000 kg/yr in the screening
assessment, the EPA finds that the chronic noncancer HQ for 2-BEB is
below levels of concern at 1.6E-1.
The EPA's screening assessment also evaluated potential acute
exposure
[[Page 59777]]
levels. As indicated above, a 10x acute factor was applied to emissions
from manufacturing and processing to account for surges in emissions
from the batch manufacturing and processing emissions points.\42\
Assuming that 2-BEB slowly partitions into the air from wastewater
throughout the year, a factor of 1x was used for acute air emissions
from wastewater. Based on the EPA's screening assessment of potential
acute exposure levels, the Agency determined the maximum 1-hour
concentrations to be 2.5E-4 mg/m\3\ from manufacturing and processing
and 3.2E-2 mg/m\3\ from wastewater. The acute noncancer HQ for
manufacturing and processing from the EPA's screening analysis is 2.7E-
2 and was calculated by dividing the acute concentration of 2-BEB from
manufacturing and processing by the California Reference Exposure Level
(REL) for EGME and then multiplying by an acute factor of 10 (acute
noncancer HQ = 2.5E-4 mg/m\3\ divided by 0.093 mg/m\3\ times 10). The
acute noncancer HQ for wastewater from the EPA's screening analysis is
3.43E-1 and was calculated by dividing the acute concentration of 2-BEB
from wastewater by the California REL for EGME (acute noncancer HQ =
3.2E-2 mg/m\3\ divided by 0.093 mg/m\3\). The total acute HQ is 3.7E-1
and was calculated as the sum of the HQ for manufacturing and
processing and wastewater (total HQ = 2.7E-2 + 3.43E-1). Even with
conservative screening assumptions, the acute HQ (REL) for 2-BEB is
below 1 and, therefore, indicates that acute noncancer risk is below
levels of concern. Based on the results of the acute inhalation study
in rats (which showed no acute effects even at very high
concentrations, discussed in section II.C. of this preamble), the
Petitioner concluded that 2-BEB was not likely to cause acute effects.
Thus, the Petitioner did not perform an evaluation of the acute
inhalation risks. This largely agrees with the acute inhalation risk
analysis that the EPA performed out of an abundance of caution.
---------------------------------------------------------------------------
\42\ Note that, since the acute screen already includes a 10x
factor for emissions, the acute analysis was performed using the
``maximum'' production volume estimate only.
---------------------------------------------------------------------------
C. Oral and Dermal Exposure
For oral and dermal exposures, the Petitioner estimated possible
exposures of adults (18+ years), children (6-12 years), and young
children (1-5 years). Regarding workplace exposures and acute events
resulting from workplace accidents, it is the EPA's longstanding view
that these kinds of exposures are beyond the scope of consideration for
HAP delisting actions because CAA section 112(b)(3)(C) only references
``emissions, ambient concentrations, bioaccumulation, or deposition of
the substance.\43\ For all other scenarios, the Petitioner assumed its
modeled ambient water concentration of 3.84E-11 mg/L.
---------------------------------------------------------------------------
\43\ See, e.g., 70 FR 75055, Dec. 15, 2005 (explaining that the
``EPA cannot consider the health effects of emissions within
facility boundaries. That is the purview of the Occupational Safety
and Health Administration.''(final rule delisting methyl ethyl
ketone as a HAP)); 61 FR 30816, 30821, June 18, 1996 (explaining
that ``it would be illogical to assume that worker exposures should
be considered in deciding whether to delist [a HAP] when continued
listing would not itself lead to any requirement that occupational
exposures be controlled.'' (final rule delisting caprolactam as a
HAP.)).
---------------------------------------------------------------------------
For the analysis, the EPA derived dermal and ingestion values for
the exposure factors from the EPA's Exposure Factors Handbook.\44\
Although uptake via the oral and dermal routes likely have different
absorption efficiencies, an oral exposure results in a first pass of
the chemical substance through the liver while dermal exposure does
not. The EPA's estimates of uptake of 2-BEB for dermal and ingestion
exposures are provided in table 4. For this evaluation, the EPA used
the water concentration of 3.84E-11 mg/L, which is the same
concentration assumed by the Petitioner. In the EPA's evaluation, the
possible uptakes via both routes were added to estimate a total
possible internal dose. As a result of the findings of the acute oral
study submitted by the Petitioner, the EPA believes that it is
reasonable that an oral screening value would be protective against any
potential acute dermal effects.\45\
---------------------------------------------------------------------------
\44\ U.S. Environmental Protection Agency (EPA). (2011).
Exposure Factors Handbook: 2011 Edition (EPA/600/R-09/052F).
National Center for Environmental Assessment, Washington, DC.
Available at: https://www.epa.gov/expobox/about-exposure-factors-handbook.
\45\ For additional information on the EPA's analysis, see the
memo titled ``ICF Review of the Dow Chemical Company petition to the
U.S. Environmental Protection Agency under the Clean Air Act,
section 112(b)(3) to Remove 2-Butoxyethyl Benzoate (2-BEB, CAS RN
5451-76-3) from the Glycol Ethers Category in the List of Hazardous
Air Pollutants dated September 30, 2019,'' which is available in the
docket for this action.
Table 4--Uptake via Ingestion and Dermal Exposures to 2-BEB in Water
----------------------------------------------------------------------------------------------------------------
Child 6 to <11 Child 1 to <6
Dermal and ingestion uptake Adult yr yr
----------------------------------------------------------------------------------------------------------------
Exposure Factor Values:
Skin surface area (cm\2\), upper 95th percentile............ 25,000 14,800 8,320
Body weight (kg), mean...................................... 80 31.8 13.5
Skin permeability coefficient (cm/hr)....................... 0.012 0.012 0.012
Drinking water ingestion (L/day), upper 95th percentile..... 2.938 1.258 0.8134
Absorption via dermal or oral routes, assumed............... 100% 100% 100%
Incidental ingestion rate while swimming (mL/hr),........... 92 96 96
upper 95th percentile.......................................
Swimming (min/year), upper 95th percentile.................. 2172 2172 2172
Bathing (hr/day), upper 95th percentile..................... 0.500 0.767 0.857
Estimated 2-BEB Uptake from Water:
Ingestion via drinking water (mg/kg/day).................... 1.34E-12 1.31E-12 1.80E-12
Dermal uptake when showering (mg/kg/day).................... 7.20E-14 1.64E-13 2.43E-13
Incidental ingestion when swimming (mg/kg/day).............. 4.38E-15 1.15E-14 2.71E-14
Dermal uptake during swimming (mg/kg/day)................... 1.43E-14 2.13E-14 2.82E-14
-----------------------------------------------
Total uptake (mg/kg/day)................................ 1.43E-12 1.51E-12 2.10E-12
----------------------------------------------------------------------------------------------------------------
D. Human Health Effects of 2-BEB
The EPA is unaware of any verified chronic or subchronic inhalation
studies on 2-BEB. Due to the lack of health benchmarks or speciated
exposure data for 2-BEB and other HAP in the glycol ethers category,
the EPA used the EGME health benchmark to conduct an initial risk
screen for human health effects that
[[Page 59778]]
was based on total glycol ethers exposure.\46\ The EPA assumes that
there is no relevant potential for risk from exposure to the glycol
ethers category if no risk is found when assuming that 100% of the
glycol ethers exposure is to EGME. Therefore, the EPA finds the use of
the RfC for EGME to be a conservative approach for assessing the
potential for chronic risk from 2-BEB exposure. To also inform the
EPA's evaluation of the Petition, the Agency considered the worst-case
toxicity scenario using EGME and the chemical substance specific data
but did not rely on the route-to-route or EGBE-based approaches
provided by the Petitioner. The EPA determined that the worst-case
inhalation toxicity data for EGME and the submitted data concerning the
potential for health effects from oral exposure to 2-BEB are sufficient
data for deciding whether to delist 2-BEB.
---------------------------------------------------------------------------
\46\ A similar surrogate approach was applied to support the
removal of the surfactant alcohol ethoxylates and their derivatives
(SAED) from the glycol ethers category in the HAP list. In this case
the subchronic RfC for 2-methoxy-1-propanol (MP) was used as a
surrogate for SAED compounds (65 FR 47342, Aug. 2, 2000).
---------------------------------------------------------------------------
The Petitioner stated that it was unable to perform either chronic
or subchronic inhalation studies due to the low volatility of 2-BEB
(vapor pressure of 0.00029 mmHg at 20 [deg]C). The boiling point of 2-
BEB at 760 mm Hg (ambient pressure) is 282 [deg]C. Based on this low
vapor pressure and substantially high boiling point, and given that the
manufacturing and conditions of use for water-based paints occur at
ambient temperatures, the Petitioner concluded that it is unlikely that
sufficient vapor of 2-BEB can be generated under conditions that
represent those scenarios. The theoretical maximum saturated vapor
concentration was calculated by the Petitioner to be 3.5 mg/m\3\.
As discussed in section II.C. of this preamble, the Petitioner
relied on the inhalation data for EGBE to estimate the chronic risk of
2-BEB exposure to human health and, for comparison, provided a route-
to-route extrapolation based on 2-BEB oral toxicity data. To address
the uncertainty associated with estimates that are neither chemical nor
route specific, the Petitioner also performed a worst-case toxicity
analysis relying on the RfC for EGME, the most potent chemical with a
RfC available from the EPA's IRIS assessment program for the glycol
ethers category.
The results of the oral toxicity studies lead EPA to conclude that
2-BEB is not reasonably anticipated to cause developmental or
reproductive toxicity at the doses tested (up to 5,000 ppm in diet),
based on the lack of fetal loss or observed abnormalities. The RfC for
EGME is based on reproductive effects. Adverse testicular effects from
exposure to EGME were observed in rabbits and rats, with the LOAEL
identified as 311 mg/m\3\ or 100 ppm. Based on the lack of any adverse
effects observed at doses up to 1,500 ppm of 2-BEB, the EPA concludes
that the use of the EGME toxicity value is sufficiently conservative to
account for the potential for adverse reproductive, developmental, or
other noncancer effects from exposure to 2-BEB.
Further, the RfC for EGME of 0.02 mg/m\3\ is expected to
sufficiently account for any adverse inhalation noncancer effects from
potential exposure to 2-BEB's metabolite EGBE.\47\ The EPA considers
using the RfC for EGME as more conservative than using the available
chronic RfC for EGBE of 0.1 mg/m3. Further, the RfC for EGME is
expected to account for acute inhalation effects from EGBE as supported
by available acute inhalation values for EGBE that include the acute
inhalation Minimal Risk Level (MRL) of 6 ppm (28.8 mg/m\3\),\48\ the
acute inhalation REL of 4.7 mg/m3, and the 8-hr inhalation REL of 0.164
mg/m3.\49\
---------------------------------------------------------------------------
\47\ U.S. Environmental Protection Agency. (2010). IRIS
Toxicological Review of Ethylene Glycol Mono Butyl Ether (EGBE)
(Final Report), EPA/635/R-08/006F, 2010.
\48\ Agency for Toxic Substances and Disease Registry (ATSDR).
(1998). Toxicological profile for 2-butoxyethanol and 2-
butoxyethanol acetate. U.S. Department of Health and Human Services,
Public Health Service.
\49\ California Office of Environmental Health Hazard
Assessment. Ethylene Glycol Monobutyl Ether: https://oehha.ca.gov/air/chemicals/ethylene-glycol-monobutyl-ether.
---------------------------------------------------------------------------
As part of the three oral dietary repeat-dose studies (acute, 28-
day, and 90-day), the Petitioner performed a toxicokinetic evaluation
to measure the parent chemical, 2-BEB, and two of its expected
metabolites, EGBE and BAA, in the blood of the non-fasted animals using
liquid chromatography with tandem mass spectrometry detection (LC/MS-
MS). BAA has been identified as the metabolite responsible for the
hemolytic toxicity of EGBE. While the data provided suggest the BAA
metabolite may be responsible for observations of hemolytic toxicity at
the high dose exposure to 2-BEB, the data do not demonstrate that the
BAA metabolite is solely responsible for the full range of adverse
effects observed at doses of 5000 ppm.
In the 90-day study, the parent chemical (2-BEB) and two expected
metabolites (EGBE and BAA) were also measured in urine using both LC/
MS-MS and gas chromatography with tandem mass spectrometry detection
(GC/MS-MS). 2-BEB was not detected in any of the treated blood samples.
However, 2-BEB was detected in most of the treated urine samples, with
one sample in the low-dose group and all samples in the higher-dose
groups showing quantifiable levels. The levels of 2-BEB in 24-hr urine
samples from male and female rats accounted for up to 0.294% and
0.599%, respectively, of the administered dose (the daily intake of 2-
BEB) from all treatment groups. The Petitioner hypothesized that the
positive results in urine may be attributed to contamination of urine
samples with 2-BEB test diet. In all urine samples from treated rats,
2-BEB, EGBE, and BAA were all quantifiable. Toxicokinetic evaluations
in blood showed the concentrations of BAA and EGBE were linear across
dose levels in both male and female rats. While BAA showed a linear
relationship across dose levels in female rats, non-detects in treated
females prevented a toxicokinetic analysis for EGBE. However, the
toxicokinetic evaluations in urine showed that the measured
concentrations of 2-BEB, EGBE, and BAA were linear across dose levels
in both male and female rats.
The EPA performed a separate evaluation of the submitted data and
the Petitioner's estimate of an RfD based on 2-BEB toxicity data. Based
on this evaluation, the EPA has determined that the worst-case
inhalation toxicity data for EGME and the submitted data concerning the
potential for health effects from oral exposure to 2-BEB are sufficient
data for deciding whether to delist 2-BEB.
Using the rat point of departure of 100 mg/kg/day, the EPA
calculated the HED based on the available information and the
recommendations provided in EPA guidance.\50\ The resulting HED was
estimated to be 24 mg/kg/day. The EPA also applied differing UFs to
this HED. However, the EPA agreed with the Petitioner's selection of
the NOAEL based on the limited data available for 2-BEB.\51\
Additionally, the EPA agreed
[[Page 59779]]
with the Petitioner`s recommended UFH of 10 based on the
absence of human data available for 2-BEB, the potential for
interindividual differences in metabolism and excretion of the BAA
metabolite, and the potential for interindividual susceptibility to the
benzoic acid metabolite, the metabolite of 2-BEB formed in addition to
EGBE. The EPA adjusted the UFA from 3 to 1 based on the
Agency's application of default dosimetry methods to calculate the HED
and evidence that animals may be more sensitive than humans to 2-BEB's
benzoic acid, EGBE, and BAA metabolites that may drive the observed
oral toxicity of 2-BEB. This is consistent with the application of the
UFA in the IRIS assessments available for EGBE and benzoic
acid. Finally, the EPA adjusted the UFD from 3 to 10 to
address the uncertainty attributable to the very limited database
available on the toxicity of 2-BEB.
---------------------------------------------------------------------------
\50\ U.S. Environmental Protection Agency. (2011). Recommended
use of body weight \3/4\ as the default method in derivation of the
oral reference dose [EPA Report]. (EPA/100/R11/0001).
\51\ The EPA notes the Petitioner's choice not to calculate an
HED from the rat data citing species differences in the rate of
formation of, and sensitivity to, the BAA metabolite, which is
linked to hemolytic toxicity. The EPA additionally notes that the UF
of 3 is representative of half an order of magnitude (i.e., the
square root of 10) and multiplying two factors of 3 should lead to a
product of 10. In a risk assessment done by the EPA using these
factors, the total UF applied based on the Petitioner's choices
should have been 100, not 90. Further, the EPA notes some of the
choices the Petitioner made in the application of UFs. For example,
the Petitioner's selection of UFS of 1 does not consider
the non-BAA mediated or hemolytic adverse outcomes observed in the
90-day toxicity study.
---------------------------------------------------------------------------
In summary, to screen for the potential for oral risk from 2-BEB,
the EPA used the Petitioner's data and applied more conservative
values. Specifically, the EPA used the HED of 24 mg/kg/day and applied
a cumulative UF of 1,000 (UFS = 10, UFH = 10,
UFA = 1, and UFD = 10). This resulted in an oral
screening value of 0.024 mg/kg/day. This screening value is expected to
be protective of effects from 2-BEB's metabolites. Benzoic acid has an
available chronic RfD of 4 mg/kg/day, whereas EGBE has an available
intermediate MRL of 0.07 mg/kg/day. The 2-BEB chronic oral screening
value is expected to also be protective of acute oral risk from EGBE,
based on the availability of an acute oral MRL from the Agency of Toxic
Substances and Disease Registry (ATSDR) for EGBE of 0.4 mg/kg/day.
The EPA evaluated the available information on 2-BEB genotoxicity
and relied on this information to evaluate the evidence regarding the
potential for 2-BEB to cause cancer in humans. Currently, the EPA is
not aware of any available two-year carcinogenicity study for 2-BEB.
However, due to consistent evidence of non-genotoxicity in vitro, lack
of genotoxicity or lesions observed in repeated dose studies in vivo,
and supplemental evidence regarding a lack of carcinogenicity for 2-
BEB's metabolites, the EPA has concluded that the available evidence
suggests that 2-BEB is unlikely to be a carcinogen at doses below the
derived RfC and RfD.
E. Human Health Risk Characterization and Conclusions
To characterize the noncancer risk associated with exposure to 2-
BEB or EGME, we calculated a HQ. For EGME, the inhalation HQ was
developed by comparing the modeled level of exposure to the RfC for
EGME. For 2-BEB, the HQ was calculated by comparing the modeled level
of exposure to the EPA-estimated RfD for 2-BEB. If the HQ is less than
1, the reference level is not exceeded, and adverse noncancer health
effects are unlikely.
The EPA has determined that the use of the RfC for EGME is health
conservative. The Petitioner points out that the critical effect used
to derive the RfC for EGME is a potential effect on the testes, but
that no effect on the testes has been observed with 2-BEB. Similarly,
the EPA finds that there is no data to support that 2-BEB would be
expected to be equal to or greater in toxicity than EGME. In addition,
the EGME RfC criterion includes margins of safety built into the IRIS
RfC (i.e., any needed UFs to address sensitive subpopulations and other
factors) and, therefore, accounts for sensitive subpopulations.
The EPA also finds that the Petitioner performed the dispersion
modeling analysis following appropriate modeling guidance for a
screening assessment. To verify the Petitioner's results, the EPA
conducted a screening assessment using the Petitioner's 2-BEB emissions
estimates, a HEM screening tool that uses data from AERMOD, and
conservative assumptions, including the use of the RfC for EGME.\52\
---------------------------------------------------------------------------
\52\ U.S. Environmental Protection Agency. AERMOD Modeling
System Development: https://www.epa.gov/scram/aermod-modeling-system-development.
---------------------------------------------------------------------------
Using the ``maximum'' production volume estimate of 275,000 kg/yr,
the HQ for 2-BEB based on the EPA's conservative screening analysis,
3.6E-2, is approximately one order of magnitude higher than the HQ
estimated by the Petitioner of 1.1E-3. The primary reason the EPA's
screen resulted in a higher concentration is that the Agency used much
more conservative fugitive release parameters. Regardless, both screens
result in an HQ value for 2-BEB that is well below 1 and, therefore,
indicate that chronic noncancer risk is below the presumed level of
concern. In addition, the EPA performed the chronic noncancer screen
using the ``high end--unrealistic'' production volume estimate of
2,300,000 kg/yr and the HQ for 2-BEB based on the same conservative
screening values was still below 1 at 1.6E-1.
The EPA's screen also included an estimate of the acute noncancer
risk using the REL for EGME of 0.093 mg/m\3\. As indicated above, a 10x
acute factor was applied to emissions from manufacturing and processing
to account for surges in emissions from the batch manufacturing and
processing emissions points (note that, since the acute screen already
includes a 10x factor for emissions, the acute analysis was performed
using the ``maximum'' production volume estimate only). Since the EPA
assumes that 2-BEB slowly partitions into the air from the water
throughout the year, a factor of 1x was used for acute air emissions
from water. Table 5 shows the calculations of the acute HQs based on
the REL from the EPA's screen:
[[Page 59780]]
Table 5--Acute HQ (REL) for 2-BEB Based on the EPA's Screen
----------------------------------------------------------------------------------------------------------------
Max 1-hour
Source concentration Acute factor Acute HQ (REL)
(mg/m\3\)
----------------------------------------------------------------------------------------------------------------
Manufacturing and Processing.................................... 2.5E-4 10 2.71E-2
Wastewater...................................................... 3.2E-2 1 3.43E-1
-----------------------------------------------
Total....................................................... .............. .............. 3.7E-1
----------------------------------------------------------------------------------------------------------------
Even with conservative screening assumptions, the acute HQ (REL)
for 2-BEB is well below 1 and, therefore, indicates that acute
noncancer risk is below levels of concern.
In summary, the Petitioner's modeling analysis demonstrated that,
using conservative assumptions, the maximum noncancer HQ is well below
1 and therefore below levels of concern. This finding was confirmed by
the EPA's own screening analysis. In addition, the EPA's screening
analysis indicated that the acute HQ, based on the maximum 1-hour
concentration and the application of acute factors, was also below 1
and therefore below levels of concern. Therefore, the EPA does not
anticipate inhalation exposure to 2-BEB to occur at levels of concern
for human health.
Regarding ingestion and dermal exposures, the Petitioner summarizes
various HQs it estimated for ingestion and dermal exposures in table 17
of the Petition. None exceed 1.29E-11 (youngest age group, ingestion
exposure). The Petitioner used an RfD of 0.19 based on 2-BEB's molar
equivalent of EGBE. The EPA also performed a seperate risk screening
analysis for oral and dermal expsoure to 2-BEB. As shown in the last
row of table 6, the total HQs for dermal and ingestion exposures are
well below 1 and therefore below levels of concern. The screening level
the EPA used to determine 2-BEB's ingestion HQ is the EPA's screening
oral value based on the Petitioner's 2-BEB toxicity data of 0.024 mg/
kg/day. Based on the EPA's analysis, the Agency expects that maximum
exposures to 2-BEB via ingestion of water contaminated with 2-BEB from
air releases are unlikely to exceed 0.024 mg/kg/day. The resulting HQs
for adults and children are well below 1, ranging from 5.96E-11 to
8.75E-11. Therefore, the EPA's analysis of dermal and ingestion
exposures confirms the Petitioner's findings.\53\
---------------------------------------------------------------------------
\53\ For additional information on the EPA's analysis, see the
memo titled ``ICF Review of the Dow Chemical Company petition to the
U.S. Environmental Protection Agency under the Clean Air Act,
section 112(b)(3) to Remove 2-Butoxyethyl Benzoate (2-BEB, CAS RN
5451-76-3) from the Glycol Ethers Category in the List of Hazardous
Air Pollutants dated September 30, 2019'' in the docket for this
rulemaking.
Table 6--Hazard Quotients for Dermal and Ingestion
----------------------------------------------------------------------------------------------------------------
Child 6 to <11 Child 1 to <6
Dermal and ingestion Adult yr yr
----------------------------------------------------------------------------------------------------------------
Total uptake (mg/kg/day)........................................ 1.43E-12 1.51E-12 2.10E-12
Hazard Quotient (total uptake/0.024 mg/kg/day).................. 5.96E-11 6.29E-11 8.75E-11
----------------------------------------------------------------------------------------------------------------
Therefore, based on the EPA's evaluation of information presented
in the Petition, data made available after the submission of the
Petition, and the Agency's own analyses, we have made an initial
determination that emissions, ambient concentrations, bioaccumulation,
or deposition of 2-BEB may not reasonably be anticipated to cause any
adverse effects to human health.
F. Ecological Risk Characterization and Conclusions
2-BEB has moderate solubility in water (106 mg/L) and low vapor
pressure. These properties lead to the potential for 2-BEB air
emissions to deposit into water systems, which can result in ecological
exposure. Considering the mammalian data on metabolism and the
predicted fish biotransformation, the EPA expects that 2-BEB would be
quickly metabolized in fish and, therefore, agrees with the
Petitioner's finding that 2-BEB would be unlikely to bioaccumulate in
aquatic food chains. In addition, based on the EQC multimedia fugacity
modeling conducted by the Petitioner, the EPA agrees that 2-BEB is
expected to readily degrade (hydrolyze) after release to air and
deposition to soils and surface waters.
The exposure estimates for the environment were based on
concentrations predicted by the Equilibrium Partitioning (EQP) model
worst-case projected emissions to air only. The EPA has summarized the
Petitioner's data from appendix 2, tables 3 and 4 in table 7, below.
The HQ values for water and soil in the last row of table 7 are 10
orders of magnitude below the HQ of 1. Even though the EPA considers
the Petitioner's exposure estimates to be uncertain, it is unlikely
that environmental concentrations were underestimated by 10 orders of
magnitude. Thus, the very low HQs indicate that the potential for
adverse environmental effects is too low to be of concern.\54\
---------------------------------------------------------------------------
\54\ For additional information on the EPA's analysis, see the
memo titled ``ICF Review of the Dow Chemical Company petition to the
U.S. Environmental Protection Agency under the Clean Air Act,
section 112(b)(3) to Remove 2-Butoxyethyl Benzoate (2-BEB, CAS RN
5451-76-3) from the Glycol Ethers Category in the List of Hazardous
Air Pollutants dated September 30, 2019,'' which is available in the
docket for this action.
Table 7--Potential for Adverse and Widespread Effects of 2-BEB in the Environment is Low
----------------------------------------------------------------------------------------------------------------
Air (mg/m\3\) Water (mg/L) Soil (mg/kg Sediment (mg/
Parameter \a\ \b\ dw) \b\ kg dw) \a\
----------------------------------------------------------------------------------------------------------------
EQP-Estimated Concentration..................... 5.4E-11 2.02E-12 1.19E-10 2.31E-11
[[Page 59781]]
PNEC............................................ NR 6.59E-3 2.5 NC
Hazard Quotient (HQ)............................ NR 3.07E-10 4.75E-11 NC
----------------------------------------------------------------------------------------------------------------
2-BEB = 2-butoxyethyl benzoate; EQP = Equilibrium Partitioning modeling based on the Equilibrium Criterion (EQC)
multimedia fugacity model; PNEC = predicted no-effect concentration; dw = dry weight; NR = not relevant; NC =
not calculated.
\a\ From table 3 of Attachment 2 to the petition.
\b\ From table 4 of Attachment 2 to the petition.
G. Conclusions
The proposal to grant the Petition is based on the EPA's evaluation
of the Petition and available information concerning the potential
hazards and projected exposures to 2-BEB.\55\ The EPA made an initial
determination that there are adequate data on the health and
environmental effects of 2-BEB to determine that emissions, ambient
concentrations, bioaccumulation, or deposition of 2-BEB may not
reasonably be anticipated to cause adverse human health or
environmental effects. This action therefore includes the EPA's
detailed rationale for proposing to grant the Petition to delete 2-BEB
from the glycol ethers category of HAP under CAA section 112(b)(1). If,
after opportunity for public comment and review of those comments, the
EPA makes the final determination to grant the Petition, the deletion
of 2-BEB will be codified in 40 CFR part 63, subpart C.
---------------------------------------------------------------------------
\55\ See e.g., 70 FR 75056 (final rule delisting methyl ethyl
ketone as a HAP); 69 FR 69322 (final rule delisting ethylene glycol
monobutyl ether as a HAP); 61 FR 30822 (final rule delisting
caprolactam as a HAP).
---------------------------------------------------------------------------
In section III.D., the EPA also discussed uncertainty with respect
to available evidence of the risk of 2-BEB. Uncertainty is an inherent
part of risk assessment that requires the integration of multiple
factors and predictions of risk that are not directly observable. For
decisions that are based largely on risk assessments, some degree of
uncertainty is acceptable and unavoidable.
To this end, the risk assessment applies conservative toxicity and
exposure assumptions to bias potential error toward overstating human
and ecological health effects. Thus, the EPA is confident that even
when we consider the uncertainties in the Petition's initial assessment
and in the additional analyses by the EPA and the Petitioner, the
results are more likely to overestimate rather than underestimate true
exposures and risks.\56\ The EPA long maintained that CAA section
112(b)(3)(C) does not require absolute certainty that a pollutant will
not cause adverse effects on human health or the environment before it
may be deleted from the HAP list. For example, the EPA has previously
explained that the terms ``adequate'' and ``reasonably'' in CAA section
112(b)(3)(C) indicate that the Agency must weigh the potential
uncertainties and the likely significance of any projections,
assessments, and estimations.\57\
---------------------------------------------------------------------------
\56\ For example, the EPA has also long acknowledged that the
maximum individual lifetime cancer risk, under CAA section
112(f)(2), ``does not necessarily reflect the true risk, but
[rather] displays a conservative risk level which is an upper-bound
that is unlikely to be exceeded.'' National Emissions Standards for
Hazardous Air Pollutants: Benzene Emissions from Maleic Anhydride
Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels,
Benzene Equipment Leaks, and Coke By-Product Recovery Plants
(Benzene NESHAP) (54 FR 38044, 38045 (Sep. 14, 1989).
\57\ See e.g., 70 FR 75047, 75048 (Dec. 19, 2005) (final rule
delisting methyl ethyl ketone as a HAP). The final decision involves
the consideration and balancing of factors that are uniquely within
the Administrator's expertise, including policy choices, and
predictions on ``the frontiers of scientific knowledge.'' Nat'l Lime
Ass'n v. EPA, 627 F.2d 416, 454 (D.C. Cir. 1980); See also Baltimore
Gas & Elec. Co. v. NRDC, 462 U.S. 87, 103 (1983).
---------------------------------------------------------------------------
Uncertainty arises for several reasons in the risk assessment for
2-BEB, including that the physicochemical properties of 2-BEB make it
difficult to directly assess the inhalation toxicity. Further, the use
of a worst-case toxicity IRIS value for EGME as the source of the human
health effects decision criteria, while considered a conservative
approach, is imperfect and leads to uncertainty in characterizing the
risk of inhalation exposure to 2-BEB. Additionally, there are gaps in
the database of toxicity information available for 2-BEB with little to
no scientific data available outside of what the Petitioner provided.
No chronic oral exposure study is available for 2-BEB. While the
potential for oral or dermal risk was estimated to be very low based on
the data available, this represents an area of uncertainty addressed in
part by the application of the 10-fold subchronic UFS.
Further, the adverse health outcomes observed in the 90-day oral
toxicity study mirror those observed in animals for 2-BEB's metabolite,
benzoic acid. In the IRIS assessment of benzoic acid,\58\ animals were
considered to be a poor predictor of human toxicity levels based on the
observation of effects in chronic animal studies at levels generally
recognized as safe for humans by the Food and Drug Administration
(FDA). However, the RfD for benzoic acid was set in 1988 based on a
study conducted by the FDA in 1973 and is likely out of date. The EPA
also recognizes that uncertainty exists in the EQC multimedia fugacity
model used to predict the fate and transport of 2-BEB in the
environment. These models are simplifications of reality, and some
variables are excluded. For example, in the EQC model, the
characteristics of the environment are fixed to facilitate chemical-to-
chemical comparison.\59\ The EPA believes these uncertainties are
largely addressed by using the reference value for the more toxic EGME
(which incorporates UFs) and the conservative assumptions used in the
emissions and exposure assessments. Taken together, these assumptions
bias any potential error towards overstating the human health effects,
even considering the uncertainties described above.
---------------------------------------------------------------------------
\58\ U.S. Environmental Protection Agency. (1988). IRIS Chemical
Assessment Summary of Benzoic Acid. Available at: https://iris.epa.gov/static/pdfs/0355_summary.pdf.
\59\ Trent University. EQC (EQuilibrium Criterion) Model:
https://www.trentu.ca/cemc/resources-and-models/eqc-equilibrium-criterion-model.
---------------------------------------------------------------------------
Regarding carcinogenicity, the information available to the EPA
currently indicates a lack of genotoxicity for 2-BEB and no evidence
suggests carcinogenicity at levels below the oral noncancer screening
level of 0.024 mg/kg/day and the EGME RfC of 0.02 mg/m\3\. If
additional information on 2-BEB is provided to the EPA between the
proposal and the final action on this delisting decision, the Agency
expects to evaluate and peer-review such information.
Additionally, regarding environmental effects, the HQ values for
water and soil are 10 orders of magnitude below the HQ of 1. Even
though the EPA considers the Petitioner's exposure estimates to be
uncertain, it is unlikely that
[[Page 59782]]
environmental concentrations of 2-BEB were underestimated by 10 orders
of magnitude. Thus, the EPA reasonably expects that the potential for
adverse environmental effects posed by emissions of 2-BEB would be low.
In conclusion, upon the showing made by the Petitioner, the EPA has
made an initial determination that there are adequate data on the
potential health and environmental effects of 2-BEB. Based on this
data, the EPA has determined that emissions, ambient concentrations,
bioaccumulation, or deposition of 2-BEB may not reasonably be
anticipated to cause any adverse effects to the human health or adverse
environmental effects. Therefore, the EPA proposes to grant the
Petition and delete 2-BEB from the glycol ethers category of the HAP
list.
IV. Proposed Amendments to 40 CFR Part 63, Subpart C
The EPA is proposing to amend 40 CFR part 63, subpart C to codify
the deletion of 2-BEB from the glycol ethers category in the HAP list
established by 42 U.S.C. 7412(b)(1). Additionally, the EPA intends to
reorganize 40 CFR part 63, subpart C to provide clarity and allow space
for future amendments. The EPA is not, however, reopening for comment
any of the previous decisions currently codified in 40 CFR part 63,
subpart C. The EPA is making a ministerial, administrative revision to
better reorganize the subpart and is not reexamining either the broader
regulatory framework or specified earlier delisting decisions.
Specifically, the EPA intends to reorganize subpart C to dedicate
40 CFR 63.61 to deletions from the HAP list and 40 CFR 63.62 to
additions to the HAP list. Under 40 CFR 63.61, the EPA intends to begin
each paragraph with a paragraph heading that states the delisted HAP.
Under 40 CFR 63.62, the EPA intends to begin each paragraph with a
heading that states the listed HAP.
Additionally, the EPA intends to revise the entry for EGBE to
state: ``deleted from the glycol ethers category in the list of
hazardous air pollutants established by 42 U.S.C. 7412(b)(1)'' instead
of ``deleted from the list of hazardous air pollutants established by
42 U.S.C. 7412(b)(1).'' The EPA is not, however, reopening for comment
the previous delisting decision for EGBE.
A memorandum showing the rule edits that would be necessary to
incorporate the changes to 40 CFR part 63, subpart C is available in
the docket for this rulemaking (Docket ID No. EPA-HQ-OAR-2024-0392).
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review.
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
This action is expected to be an Executive Order 14192 deregulatory
action. This proposed rule is expected to provide burden reduction by
removing a compound from the HAP list, therefore decreasing the
regulatory burden of any facility that uses or plans to use the
compound.
C. Paperwork Reduction Act (PRA)
This action does not impose an information collection burden under
the PRA. The final action will remove 2-BEB from the CAA section
112(b)(1) HAP list and, therefore, eliminate the need for information
collection under the CAA.
D. 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. In
making this determination, the EPA concludes that the impact of concern
for this rule is any significant adverse economic impact on small
entities and that the Agency is certifying that this rule will not have
a significant economic impact on a substantial number of small entities
because the rule relieves regulatory burden on the small entities
subject to the rule. The acceptance of this proposal would delist a HAP
currently listed under CAA section 112(b)(1); therefore, the regulatory
burden would decrease. The EPA has therefore concluded that this action
would relieve regulatory burden for all directly regulated small
entities.
E. Unfunded Mandates Reform Act (UMRA)
This action does not contain an unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. The action imposes no enforceable duty on any state,
local or Tribal governments or the private sector.
F. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This action does not have Tribal implications as specified in
Executive Order 13175. It will not have substantial direct effects on
Tribal governments, 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, as specified in
Executive Order 13175. Thus, Executive Order 13175 does not apply to
this action.
H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
Executive Order 13045 directs Federal agencies to include an
evaluation of the health and safety effects of the planned regulation
on children 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 a significant
regulatory action under section 3(f)(1) of Executive Order 12866, and
because the EPA does not believe the environmental health or safety
risks addressed by this action present a disproportionate risk to
children. This determination is based on the fact that the RfC is
determined to be protective of sensitive sub-populations, including
children.
EPA's Policy on Children's Health applies to this action. Section
III.E. of this preamble describes the analyses conducted to determine
the human health impacts of 2-BEB for all populations, including
children. We have made an initial determination that 2-BEB may not
reasonably be anticipated to cause any adverse effects to human health,
including children.
I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.
[[Page 59783]]
J. National Technology Transfer and Advancement Act (NTTAA)
This rulemaking does not involve technical standards.
Lee Zeldin,
Administrator.
[FR Doc. 2025-23566 Filed 12-19-25; 8:45 am]
BILLING CODE 6560-50-P