[Federal Register Volume 89, Number 232 (Tuesday, December 3, 2024)]
[Notices]
[Pages 95779-95782]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-28286]
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ENVIRONMENTAL PROTECTION AGENCY
[EPA-HQ-OPPT-2024-0425; FRL-12241-02-OCSPP]
1,3-Butadiene; Draft Risk Evaluation Under the Toxic Substances
Control Act (TSCA); Science Advisory Committee on Chemicals (SACC) Peer
Review; Notice of SACC Meeting, Availability of Draft Documents and
Request for Comment
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: The Environmental Protection Agency (EPA or Agency) is
announcing the availability of and soliciting public comment on the
draft risk evaluation for 1,3-butadiene. The draft risk evaluation was
prepared under the Toxic Substances Control Act (TSCA) and will be
submitted to the Science Advisory Committee on Chemicals (SACC) for
peer review. EPA is also announcing that there will be two virtual
public meetings of the SACC: On February 4, 2025, a preparatory meeting
for the SACC to consider the scope and clarity of the draft charge
questions for the peer review; and on February 25 through 28, 2025, the
peer review meeting for the SACC to consider the draft documents and
public comments.
DATES:
Preparatory Public Meeting:
Meeting date: February 4, 2025, 1:00 p.m. to approximately 4:00
p.m. (ET).
Registration: To request time to present oral comments during the
preparatory meeting, you must register by noon (12:00 p.m. ET) on
January 31, 2025. For those not making oral comments, registration will
remain open through the end of this meeting on February 4, 2025.
Comments: Submit written comments on the scope and clarity of the
charge questions, by noon (12:00 p.m. ET) on January 28, 2025. (Submit
a written version of your oral comments by noon (12:00 p.m. ET) on
January 31, 2025.)
SACC Peer Review Public Meeting:
Meeting dates: February 25 through 28, 2025, 10:00 a.m. to
approximately 5:00 p.m. (ET).
Registration: To request time to present oral comments during the
peer review meeting, you must register by noon, February 18, 2025. For
those not making oral comments, registration will remain open through
the end of this meeting on February 28, 2025.
Comments: Submit written comments on the draft documents, and
written version of your oral comments, on or before February 3, 2025.
Special Accommodations: To allow sufficient time for EPA to process
your request for special accommodations before the meeting, please
submit the request at least ten business days in advance of the
relevant meeting.
ADDRESSES:
Comments: Submit written comments, identified by docket
identification (ID) number EPA-HQ-OPPT-2024-0425, through https://www.regulations.gov. Follow the online instructions for submitting
comments. Do not submit electronically any information you consider to
be Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Additional information on
commenting or visiting the docket, along with more information about
dockets generally, is available at https://www.epa.gov/.
Meeting Registration: Online registration will be available
beginning in January 2025. Please refer to the SACC website at https://www.epa.gov/tsca-peer-review. After registering, you will receive the
webcast and streaming service meeting links and audio teleconference
information.
Special accommodation requests: To request an accommodation for a
disability, please contact the Designated Federal Official (DFO) listed
under FOR FURTHER INFORMATION CONTACT.
FOR FURTHER INFORMATION CONTACT:
Designated Federal Official (DFO): Alie Muneer, Mission Support
Division (7602M), Office of Program Support, Office of Chemical Safety
and Pollution Prevention, Environmental Protection Agency; telephone
number: (202) 564-
[[Page 95780]]
6369 or call the main office number: (202) 564-8450; email address:
[email protected].
Technical information: Brooke Porter, Existing Chemicals Risk
Management Division, Office of Pollution Prevention and Toxics, Office
of Chemical Safety and Pollution Prevention, Environmental Protection
Agency; telephone number: (202) 564-6388; email address:
[email protected].
SUPPLEMENTARY INFORMATION:
I. Executive Summary
A. What action is the Agency taking?
EPA is announcing the availability of and soliciting public comment
on the draft risk evaluation for 1,3-butadiene. The draft risk
evaluation was prepared under the Toxic Substances Control Act (TSCA)
and will be submitted to the Science Advisory Committee on Chemicals
(SACC) for peer review. EPA is also announcing that there will be two
virtual public meetings of the SACC: On February 4, 2025, a preparatory
meeting for the SACC to consider the scope and clarity of the draft
charge questions for the peer review; and on February 25 through 28,
2025, the peer review meeting for the SACC to consider the draft risk
evaluation and public comments.
This document provides instructions for accessing the materials,
submitting written comments, and registering to provide oral comments
and attend the public meetings.
B. What is the Agency's authority for taking this action?
EPA established the SACC in 2016 in accordance with TSCA, 15 U.S.C.
2625(o), to provide independent advice and expert consultation with
respect to the scientific and technical aspects of issues relating to
the implementation of TSCA. The SACC operates in accordance with the
Federal Advisory Committee Act (FACA), 5 U.S.C. 10, and supports
activities under TSCA, 15 U.S.C. 2601 et seq., the Pollution Prevention
Act (PPA), 42 U.S.C. 13101 et seq., and other applicable statutes.
C. Does this action apply to me?
This action is directed to the public in general and may be of
particular interest to those involved in the manufacture, processing,
distribution, and disposal of the subject chemical substances, and/or
those interested in the assessment of risks involving chemical
substances and mixtures regulated under TSCA (including members of at-
risk communities, non-governmental organizations (NGOs), federal,
state, and local officials). Since other entities may also be
interested, the Agency has not attempted to describe all the specific
entities that may be interested.
D. What should I consider as I submit my comments to EPA?
1. Submitting CBI. Do not submit CBI or other sensitive information
to EPA through https://www.regulations.gov or email. To include
information in your comment that you consider to be CBI or otherwise
protected, please contact the DFO listed under FOR FURTHER INFORMATION
CONTACT to obtain special instructions before submitting that
information.
2. Tips for preparing comments. When preparing and submitting your
comments, see https://www.epa.gov/dockets/commenting-epa-dockets. See
also the instructions in Unit III.C.
E. How can I stay informed about SACC activities?
You may subscribe to the following listserv for alerts regarding
this and other SACC-related activities: https://public.govdelivery.com/accounts/USAEPAOPPT/subscriber/new?topic_id=USAEPAOPPT_101.
II. Background
A. What is the purpose of the SACC?
The SACC provides independent advice and recommendations to the EPA
on the scientific and technical aspects of risk assessments,
methodologies, and pollution prevention measures and approaches for
chemicals regulated under TSCA. The SACC is composed of experts in
toxicology; environmental risk assessment; exposure assessment; and
related sciences (e.g., synthetic biology, pharmacology, biotechnology,
nanotechnology, biochemistry, biostatistics, physiologically based
pharmacokinetic (PBPK) modeling, computational toxicology,
epidemiology, environmental fate, and environmental engineering and
sustainability). When needed, the SACC committee will be assisted by ad
hoc reviewers with specific expertise in the topics under
consideration.
B. Why is EPA conducting these risk evaluations?
TSCA requires EPA to conduct risk evaluations on prioritized
chemical substances and allows chemical manufacturers to request an
EPA-conducted risk evaluation of a chemical substance (or category of
chemical substances) using the procedures established in 40 CFR 702.37.
TSCA also identifies the minimum components EPA must include in all
chemical substance risk evaluations. The purpose of conducting risk
evaluations is to determine whether a chemical substance presents an
unreasonable risk to human health or the environment under the
Conditions of Use (COUs). These evaluations include assessing
unreasonable risks to relevant potentially exposed or susceptible
subpopulations. As part of this process EPA: (1) Integrates hazard and
exposure assessments using the best available science that is
reasonably available to ensure decisions are based on the weight of the
scientific evidence, and (2) Conducts peer review for risk evaluation
approaches that have not been previously peer-reviewed.
For more information about the TSCA risk evaluation process for
existing chemicals, go to https://www.epa.gov/assessing-and-managing-chemicals-under-tsca.
C. Why is EPA evaluating this chemical substance?
In 2020, EPA issued final scope documents for the 20 chemical
substances designated in December 2019 as High-Priority Substances for
the TSCA risk evaluation process, which included 1,3-butadiene. The
final scope documents outline the hazards, exposures, conditions of
use, and the potentially exposed or susceptible subpopulations the
Agency expected to consider in its risk evaluation for the substances
(85 FR 55283, September 4, 2020 (FRL-10013-90)).
1,3-Butadiene (CASRN 106-99-0) is a volatile, colorless gas with a
total U.S. production volume between 1 and 5 billion pounds. It is
produced in petrochemical processing and extracted and further
processed as a building block for several polymers and elastomers that
do not readily depolymerize. Air is expected to be the major pathway of
exposure for 1,3-butadiene in the environment. Although 1,3-butadiene
is moderately soluble in water, monitoring data indicate that it is not
detected in water. Environmental release data show that more than 98
percent of 1,3-butadiene facility releases are to air. Once in air,
1,3-butadiene will not deposit to land or adsorb to organic matter due
to its chemical properties. Long-range transport in air is not
expected, in part, because 1,3-butadiene has a short half-life (<8
hours) and will degrade into formaldehyde and acrolein.
Reduced fetal body weight and hematological effects are indicated
as the most sensitive and robust non-cancer human health hazards. EPA
has classified 1,3-butadiene as a human carcinogen and epidemiology
studies have demonstrated an association between 1,3-butadiene exposure
and
[[Page 95781]]
increased incidence of leukemia in workers.
D. What is the topic of the planned SACC peer review?
EPA is submitting the draft risk evaluation of 1,3-butadiene and
associated supporting documents to the SACC for peer review, along with
the public comments received. The draft risk evaluation includes
analyses of physical chemical properties, the fate and transport in the
environment, releases to the environment, exposure to workers and the
general population, including potentially exposed susceptible
subpopulations, environmental risk characterization, and human health
hazard and risk characterization for workers and the general
population.
EPA is focusing its peer review charge on specific scientific areas
and analyses. Many of the methods and analyses used in these
evaluations are not novel and have been reviewed in the development of
previous TSCA assessments. EPA is requesting feedback on approaches,
results and calculations associated with the exposure, human health
hazard, and environmental hazard analyses. EPA is releasing the draft
risk evaluation for public comment and independent, expert peer review.
Once EPA receives comment and input from public comment and peer
review, revisions will be made, and the Agency will finalize the 1,3-
butadiene risk evaluation.
EPA is requesting a focused panel discussion and feedback on novel
approaches, unique exposure analyses and other calculations, and
selection of key hazard endpoints for 1,3-butadiene:
No exposure to aquatic and terrestrial species is expected
due to the physical and chemical properties of 1,3-butadiene, which is
primarily released to air and does not partition, deposit, or persist
in or on water or soil. Monitoring data indicate that 1,3-butadiene is
not detected in water. Exposure of terrestrial organisms via ambient
air will be brief due to the reactive nature of 1,3-butadiene. EPA is
seeking comment on the preliminary determination that quantitative risk
assessment for ecological taxa is not needed for 1,3-butadiene.
Reduced fetal body weight (the basis of the acute
Reference Concentration (RfC) in the 2002 IRIS Assessment) is observed
in both mice and rats following gestational exposure but is not
expected to result from a single dose of 1,3-butadiene. Further, EPA
did not identfy effects of teratogenicity or any other relevant
endpoint following single exposures at doses relevant to human exposure
scenarios. Therefore, EPA did not derive an acute point of departure
(POD) or quantify risks from acute exposures. EPA is seeking comment on
the preliminary determination that there is no appropriate POD to
support acute risk estimates.
Ovarian atrophy is an adverse effect observed only in mice
and can be attributed to a specific 1,3-butadiene metabolite
(diepoxybutane) that is less prevalent in rats and humans. EPA has
evaluated the relevance of ovarian atrophy for assessing human risk and
determined that the ovarian atrophy endpoint is not appropriate for
extrapolating to human risk due to differences in species-specific
metabolites. EPA is proposing to use decreased fetal body weight as the
basis for the intermediate and chronic points of departure for 1,3-
butadiene. EPA is seeking comment on these preliminary conclusions to
establish intermediate and chronic points of departure based on reduced
fetal body weight.
OPPT revised the inhalation unit risk (IUR) for 1,3-
butadiene presented in the IRIS 2002 assessment to incorporate updated
epidemiological cohort data. EPA is seeking comment on the mathematical
approach and new epidemiological cohort data used in the revised IUR.
OPPT also derived bladder cancer risk estimates using the same
epidemiological cohort and is seeking comment on the appropriate IUR
for evaluating cancer risk.
EPA has conducted a mutagenic mode of action analysis and
evaluating whether the use of an age-dependent adjustment factor (ADAF)
for leukemia is appropriate. EPA has preliminarily concluded that a
mutagenic mode of action is applicable to 1,3-butadiene and use of an
age-dependent adjustment factor (ADAF) for leukemia is appropriate. EPA
is seeking comment on this analysis and preliminary conclusion.
The majority of occupational exposure sampling data
points, collected from OSHA, NIOSH, and ACC's report, were not
quantifiable values but were identified as being below the limit of
detection (LOD). For datasets including exposure data that were
reported as below the LOD, EPA estimated exposure concentrations,
following EPA's Guidelines for Statistical Analysis of Occupational
Exposure Data. Based on these guidelines, EPA used the LOD value as the
high-end estimate and half the LOD as central tendency. EPA is seeking
comment on this approach and the relevance of this dataset for risk
characterization.
General population exposure to 1,3-butadiene was modeled
using the Human Exposure Model (HEM) to estimate ambient air
concentrations based on releases reported to the Toxic Release
Inventory (TRI) for years 2016 to 2021. Exposure concentrations were
modeled at discrete distances from releasing facilities and surrounding
census blocks. EPA is seeking comment on this analysis and preliminary
conclusions.
III. Public Meeting of the SACC
A. What is the purpose of the virtual public meeting(s)?
EPA is planning two virtual public meetings: (1) A preparatory
public meeting for the SACC to consider and ask questions regarding the
scope and clarity of the draft charge questions; and (2) a public peer
review meeting for the SACC to consider and peer review the draft risk
evaluation. These public meetings are part of the SACC's peer review of
the Agency's methods and novel analyses for the draft risk evaluation
of 1,3-butadiene. The agenda for these meetings will be posted in the
docket and will also be available through the SACC website.
Recommendations from this SACC review and public comments will be
considered in the development of the TSCA risk evaluation and may
inform other EPA efforts related to the assessment and regulation of
the chemical substance. The Agency will be seeking SACC review of its
data analyses and methodologies relevant to human health hazard and
exposure analyses that have not been previously peer-reviewed.
B. How can I participate in the virtual public meeting(s)?
To participate in these virtual public meetings, you must register
online to receive the webcast and streaming service meeting links and
audio teleconference information for each meeting. Online registration
will be available beginning approximately one month prior to the
meeting and will remain open through the end of the meeting. To make
oral comments during one of these meetings, follow the instructions in
this document.
C. How can I access the documents?
The draft risk evaluation for 1,3-butadiene and related documents,
including background documents, related supporting materials, and draft
charge questions, are available in the docket. As additional background
materials become available, EPA will include those additional
background
[[Page 95782]]
materials (e.g., SACC members and consultants participating in this
meeting and the meeting agenda) in the docket and through links on the
SACC website at https://www.epa.gov/tsca-peer-review.
D. How can I provide comments?
To ensure proper receipt of comments, it is imperative that you
identify docket ID No. EPA-HQ-OPPT-2024-0425 in the subject line on the
first page of your comments and follow the instructions in this
document.
1. Written comments. Submit written comments by the deadlines set
in the DATES section of this document and as described in the ADDRESSES
section of this document.
2. Oral comments. To request time to present oral comments during
one of the virtual public meetings, you must register online by the
deadlines set in the DATES section of this document. Oral comments
during the virtual public meetings are limited to 5 minutes. In
addition, each speaker should submit a written copy of their oral
comments and any supporting materials (e.g., presentation slides) to
the DFO prior to the meetings for distribution to the SACC.
E. What happens after the SACC meeting(s)?
After the SACC public meeting, the SACC will prepare the meeting
minutes and final report document summarizing its recommendations to
the EPA, which will also be available in the docket and through the
SACC website. EPA will consider the SACC recommendations and public
comments to complete the risk evaluation and unreasonable risk
determination under TSCA for this chemical substance. Under TSCA, EPA
must then initiate risk management actions to address the unreasonable
risk it identified.
Authority: 15 U.S.C. 2625(o); 5 U.S.C. 10.
Dated: November 26, 2024.
Michal Freedhoff,
Assistant Administrator, Office of Chemical Safety and Pollution
Prevention.
[FR Doc. 2024-28286 Filed 12-2-24; 8:45 am]
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