thefederalregister.org Federal Register Research Archive

Document

1,3-Butadiene; Risk Evaluation Under the Toxic Substances Control Act (TSCA); Notice of Availability

The Environmental Protection Agency (EPA or Agency) is announcing the availability of the final risk evaluation under the Toxic Substances Control Act (TSCA) for 1,3-butadiene (...

PDF versionFederalRegister.gov
<html>
<head>
<title>Federal Register, Volume 91 Issue 2 (Monday, January 5, 2026)</title>
</head>
<body><pre>
[Federal Register Volume 91, Number 2 (Monday, January 5, 2026)]
[Notices]
[Pages 264-266]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-24246]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OPPT-2018-0451 and EPA-HQ-OPPT-2024-0425; FRL-12241-05-OCSPP]


1,3-Butadiene; Risk Evaluation Under the Toxic Substances Control 
Act (TSCA); Notice of Availability

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

-----------------------------------------------------------------------

SUMMARY: The Environmental Protection Agency (EPA or Agency) is 
announcing the availability of the final risk evaluation under the 
Toxic Substances Control Act (TSCA) for 1,3-butadiene (CASRN 106-99-0). 
The purpose of risk evaluations under TSCA is to determine whether a 
chemical substance presents an unreasonable risk of injury to health or 
the environment under the conditions of use, including unreasonable 
risk to potentially exposed or susceptible subpopulations identified as 
relevant to the risk evaluation by EPA, and without consideration of 
costs or non-risk factors. EPA used the best available science to 
prepare this final risk evaluation and determined, based on the weight 
of scientific evidence, that 1,3-butadiene poses unreasonable risk to 
human health driven by specific conditions of use. EPA will now 
initiate risk management actions to address the unreasonable risk.

ADDRESSES: The docket for this action, identified by docket 
identification (ID) number EPA-HQ-OPPT-2018-0451 and EPA-HQ-OPPT-2024-
0425, is available online at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Additional 
information about dockets generally, along with instructions for 
visiting the docket in-person, is available at <a href="https://www.epa.gov/dockets">https://www.epa.gov/dockets</a>.

FOR FURTHER INFORMATION CONTACT: 
    For technical information: Kyle Spatz, Existing Chemical Risk 
Management Division (7404M), Office of Pollution Prevention and Toxics, 
Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, 
DC 20460-0001; telephone number: (202) 564-3201; email address: 
<a href="/cdn-cgi/l/email-protection#2c1d021f026e59584d484549424902787f6f6d6c495c4d024b435a"><span class="__cf_email__" data-cfemail="ebdac5d8c5a99e9f8a8f828e858ec5bfb8a8aaab8e9b8ac58c849d">[email&#160;protected]</span></a>.
    For general information: The TSCA-Hotline, Goodwill of the Finger 
Lakes, 422 South Clinton Ave., Rochester, NY 14620; telephone number: 
(202) 554-1404; email address: <a href="/cdn-cgi/l/email-protection#1541465654385d7a61797c7b70557065743b727a63"><span class="__cf_email__" data-cfemail="97c3c4d4d6badff8e3fbfef9f2d7f2e7f6b9f0f8e1">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION:

[[Page 265]]

I. Executive Summary

A. 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 (defined under 
TSCA section 3(9) to include import), processing, distribution, use, 
and disposal of 1,3-butadiene, related industry trade organizations, 
non-governmental organizations with an interest in human and 
environmental health, State and local governments, Tribal Nations, and/
or those interested in the assessment of risks involving chemical 
substances and mixtures regulated under TSCA. As such, the Agency has 
not attempted to describe all the specific entities that this action 
might apply to. If you need help determining applicability, consult the 
technical contact listed under FOR FURTHER INFORMATION CONTACT.

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

    The Agency conducted this risk evaluation under TSCA section 6, (15 
U.S.C. 2605), which requires that EPA conduct risk evaluations on 
chemical substances and identifies the minimum components EPA must 
include in the risk evaluations. Each risk evaluation must be conducted 
consistent with the best available science, be based on the weight of 
the scientific evidence, and consider reasonably available information, 
and not consider costs or non-risk factors. 15 U.S.C. 2625(h), (i), and 
(k). See also the implementing procedural regulations at 40 CFR part 
702 and for more information about the TSCA risk evaluation process for 
existing chemicals, go to <a href="https://www.epa.gov/assessing-and-managing-chemicals-under-tsca">https://www.epa.gov/assessing-and-managing-chemicals-under-tsca</a>.

C. What action is the Agency taking?

    EPA is announcing the availability of the final risk evaluation 
under TSCA for 1,3-butadiene. The purpose of risk evaluations under 
TSCA is to determine whether a chemical substance presents an 
unreasonable risk of injury to health or the environment under the 
conditions of use, including unreasonable risk to potentially exposed 
or susceptible subpopulations identified as relevant to the risk 
evaluation by EPA, and without consideration of costs or non-risk 
factors. EPA has used the best available science to prepare this final 
risk evaluation and ensured that this action is consistent with 
Executive Order 14303 ``Restoring Gold Standard Science,'' (May 23, 
2025). Based on the weight of scientific evidence, the Agency 
determined that 1,3-butadiene poses unreasonable risk to human health 
driven by specific conditions of use. EPA will now initiate risk 
management action as required pursuant to TSCA section 6(a) (15 U.S.C 
2605(a)), to address the unreasonable risk.

II. Background

A. What is 1,3-butadiene?

    1,3-Butadiene is a colorless gas with a total production volume 
(PV) in the United States between 1 and 5 billion pounds. 1,3-Butadiene 
is produced from petrochemical processing and is also used to aid in 
petrochemical manufacturing but is primarily used as a monomer to 
produce plastic and rubber products. This involves polymerization of 
1,3-butadiene with itself or with other monomers, which are then 
incorporated into various rubber and plastic articles. These synthetic 
rubbers, resins, and latex are used to manufacture tires, other rubber 
components and plastic materials. 1,3-Butadiene polymers are also used 
as viscosity agents in several formulations for adhesives, lubricants, 
and paints and coatings. These polymerization products which are 
polymeric forms of 1,3-butadiene are also referred to as 1,3-butadiene 
by some chemical safety data sheets (SDSs). This risk assessment covers 
only the monomer form of 1,3-butadiene.

B. Summary of Activities for the Risk Evaluation of 1,3-Butadiene

    On December 30, 2019, EPA announced its designation of 1,3-
butadiene as a high priority substance for risk evaluation under TSCA 
(84 FR 71924 (FRL-10003-15)). On April 9, 2020, EPA sought public 
comment on the draft scope of the 1,3-butadiene risk evaluation (85 FR 
19941(FRL-10007-11)) and, after considering public comments, issued the 
final scope on September 4, 2020 (85 FR 55281 (FRL-10013-90)). On 
December 3, 2024, EPA released the draft risk evaluation for public 
comment and external peer review by the Science Advisory Committee on 
Chemicals (SACC) (89 FR 95779 (FRL-12241-02-OCSPP)).
    These documents, other supporting documents, and public comments 
are in dockets EPA-HQ-OPPT-2018-0451 and EPA-HQ-OPPT-2024-0425. The 
following documents are being released with this notice:
    <bullet> A response to comments document titled, ``Summary of and 
Response to External Peer Review and Public Comments on the Risk 
Evaluation for 1,3-Butadiene'';
    <bullet> A non-technical summary of the final risk evaluation 
titled, ``Non-technical Summary of the TSCA Risk Evaluation for 1,3-
Butadiene''; and
    <bullet> The final risk evaluation titled, ``Risk Evaluation for 
1,3-Butadiene,'' along with multiple supporting documents.

III. Unreasonable Risk Determination

    EPA has determined that 1,3-butadiene, under the conditions of use 
(COUs), presents an unreasonable risk of injury to human health. EPA 
has determined that the unreasonable risk to human health presented by 
1,3-butadiene is driven by 11 of the 30 COUs. The 11 COUs that 
significantly contribute to the unreasonable risk determination for 
1,3-butadiene are based on identified non-cancer and cancer risk to 
workers, including 1 COU that contributes to unreasonable risk of 
injury to occupational non-users, from inhalation exposure:
    <bullet> Manufacturing--domestic manufacturing;
    <bullet> Manufacturing--importing;
    <bullet> Processing as a reactant--intermediate (adhesive 
manufacturing; all other basic organic chemical manufacturing; fuel 
binder for solid rocket fuels; organic fiber manufacturing; 
petrochemical manufacturing; plastic material and resin manufacturing; 
propellant manufacturing; synthetic rubber manufacturing; paint and 
coating manufacturing);
    <bullet> Processing as a reactant--monomer used in polymerization 
process (Synthetic rubber manufacturing; plastic material and resin 
manufacturing);
    <bullet> Processing--incorporation into formulation, mixture, or 
reaction product--monomers (plastic product manufacturing; plastic 
material and resin manufacturing; synthetic rubber manufacturing);
    <bullet> Processing--incorporation into formulation, mixture, or 
reaction product--plasticizer (asphalt paving, roofing, and coating 
materials manufacturing);
    <bullet> Processing--incorporation into article--monomer (rubber 
product manufacturing);
    <bullet> Processing--use-non-incorporative activities--fuel 
(petroleum refineries);
    <bullet> Processing--repackaging--(wholesale and retail trade fuel; 
synthetic rubber manufacturing; petrochemical manufacturing);
    <bullet> Processing--recycling; and
    <bullet> Disposal.

IV. Next Step Is Risk Management

    Consistent with TSCA section 6(a), EPA will propose a risk 
management

[[Page 266]]

regulatory action, to the extent necessary, so that 1,3-butadiene no 
longer presents an unreasonable risk. EPA expects to focus its risk 
management action on the conditions of use that significantly 
contribute to the unreasonable risk. In proposing a rule and selecting 
among requirements, consistent with TSCA section 6(c)(2), EPA will 
consider and factor in, to the extent practicable: (i) the effects of 
1,3-butadiene on health and the environment, (ii) the magnitude of 
exposure to 1,3-butadiene of human beings and the environment, (iii) 
the benefits of 1,3-butadiene for various uses, and (iv) the reasonably 
ascertainable economic consequences of the rule. Additional information 
received may inform the risk management of 1,3-butadiene and, like the 
prioritization and risk evaluation processes, there will be opportunity 
for public comment on any proposed risk management actions.

(Authority: 15 U.S.C. 2601 et seq.)

    Dated: December 30, 2025.
Nancy B. Beck,
Principal Deputy Assistant Administrator, Office of Chemical Safety and 
Pollution Prevention.
[FR Doc. 2025-24246 Filed 1-2-26; 8:45 am]
BILLING CODE 6560-50-P


</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>

Legal Citation

Federal Register Citation

Use this for formal legal and research references to the published document.

91 FR 264

Web Citation

Suggested Web Citation

Use this when citing the archival web version of the document.

“1,3-Butadiene; Risk Evaluation Under the Toxic Substances Control Act (TSCA); Notice of Availability,” thefederalregister.org (January 5, 2026), https://thefederalregister.org/documents/2025-24246/1-3-butadiene-risk-evaluation-under-the-toxic-substances-control-act-tsca-notice-of-availability.