Notice2025-15564
Superfund Tax on Chemical Substances; Request To Modify List of Taxable Substances; Notice of Filing for Chloro-Isobutene-Isoprene Rubber (n=97.75, m=2.25)
Primary source
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Published
August 15, 2025
Issuing agencies
Treasury DepartmentInternal Revenue Service
Abstract
This notice of filing announces that a petition has been filed requesting that chloro-isobutene-isoprene rubber ((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>- (C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75, m=2.25) be added to the list of taxable substances. This notice of filing also requests comments on the petition. This notice of filing is not a determination that the list of taxable substances is modified.
Full Text
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<title>Federal Register, Volume 90 Issue 156 (Friday, August 15, 2025)</title>
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[Federal Register Volume 90, Number 156 (Friday, August 15, 2025)]
[Notices]
[Pages 39468-39469]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-15564]
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DEPARTMENT OF THE TREASURY
Internal Revenue Service
Superfund Tax on Chemical Substances; Request To Modify List of
Taxable Substances; Notice of Filing for Chloro-Isobutene-Isoprene
Rubber (n=97.75, m=2.25)
AGENCY: Internal Revenue Service (IRS), Treasury.
ACTION: Notice of filing and request for comments.
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SUMMARY: This notice of filing announces that a petition has been filed
requesting that chloro-isobutene-isoprene rubber
((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>-
(C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75,
m=2.25) be added to the list of taxable substances. This notice of
filing also requests comments on the petition. This notice of filing is
not a determination that the list of taxable substances is modified.
DATES: Written comments and requests for a public hearing must be
received on or before October 14, 2025.
ADDRESSES: Commenters are encouraged to submit public comments or
requests for a public hearing relating to this petition electronically
via the Federal eRulemaking Portal at <a href="https://www.regulations.gov">https://www.regulations.gov</a>
(indicate public docket number IRS-2025-0137 or chloro-isobutene-
isoprene rubber ((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>-
(C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75,
m=2.25)) by following the online instructions for submitting comments.
Comments cannot be edited or withdrawn once submitted to the Federal
eRulemaking Portal. Alternatively, comments and requests for a public
hearing may be mailed to: Internal Revenue Service, Attn: CC:PA:01:PR
(Notice of Filing for Chloro-Isobutene-Isoprene Rubber
((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>-
(C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75,
m=2.25)), Room 5203, P.O. Box 7604, Ben Franklin Station, Washington,
DC 20044. All comments received are part of the public record and
subject to public disclosure. All comments received will be posted
without change to <a href="https://www.regulations.gov">https://www.regulations.gov</a>, including any personal
information provided. You should submit only information that you wish
to make publicly available. If a public hearing is scheduled, notice of
the time and place for the hearing will be published in the Federal
Register.
FOR FURTHER INFORMATION CONTACT: Julia Barlow at (202) 317-6855 (not a
toll-free number).
SUPPLEMENTARY INFORMATION:
Request To Add Substance to the List
(a) Overview. A petition was filed pursuant to Rev. Proc. 2022-26
(2022-29 I.R.B. 90), as modified by Rev. Proc. 2023-20 (2023-15 I.R.B.
636), requesting that chloro-isobutene-isoprene rubber
((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>-
(C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75,
m=2.25) be added to the list of taxable substances under section
4672(a) of the Internal Revenue Code (List). The petition requesting
the addition of chloro-isobutene-isoprene rubber
((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>-
(C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75,
m=2.25) to the List is based on weight and contains the information
detailed in paragraph (b) of this document. The information is provided
for public notice and comment pursuant to section 9 of Rev. Proc. 2022-
26. The publication of petition information in this notice of filing is
not a determination and does not constitute Treasury Department or IRS
confirmation of the accuracy of the information published.
(b) Petition Content.
(1) Substance name: Chloro-isobutene-isoprene rubber
((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>-
(C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75,
m=2.25).
(2) Petitioner: Arlanxeo USA LLC and Arlanxeo Canada Inc.,
importers and exporters of chloro-isobutene-isoprene rubber
((C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>-
(C<INF>5</INF>H<INF>7.31</INF>Cl<INF>0.69</INF>)<INF>m</INF>; n=97.75,
m=2.25).
(3) Proposed classification numbers:
(i) HTSUS number: 4002.39.0000.
(ii) Schedule B number: 4002.39.0000.
(iii) CAS number: 68081-82-3.
(4) Petition filing dates:
(i) Petition filing date for purposes of making a determination:
July 13, 2025.
(ii) Petition filing date for purposes of section 11.02 of Rev.
Proc. 2022-26, as modified by section 3 of Rev. Proc. 2023-20: April 1,
2023.
(5) Description from petition: Chloro-isobutene-isoprene rubber is
a halogenated copolymer of butylene and isoprene. It offers a low
permeability to gases and moisture, low glass transition temperature
and a wide vulcanization versatility with fast cure rates. Chloro-
isobutene-isoprene rubber is used for
[[Page 39469]]
tire inner tubes, hoses, seals, membranes, tank linings, conveyor
belts, protective clothing, and for consumer products.
Chloro-isobutene-isoprene rubber is made from butylene, chlorine,
and sodium hydroxide. Taxable chemicals constitute 97.36 percent by
weight of the materials used to produce this substance.
(6) Process identified in petition as predominant method of
production of substance: The predominant method of producing chloro-
isobutene-isoprene rubber involves reacting a hexane solution of butyl
rubber with elemental chlorine. Butyl rubber is produced via the
cationic copolymerization of butylene with isoprene in the presence of
a Friedel-Crafts catalyst at low temperature, around -100[deg]C.
(7) Stoichiometric material consumption equation, based on process
identified as predominant method of production:
n C<INF>4</INF>H<INF>8</INF> (butylene) + m C<INF>5</INF>H<INF>8</INF>
(isoprene) + (0.69m) Cl<INF>2</INF> (chlorine) + (0.69m) NaOH (sodium
hydroxide) [rarr]
(C<INF>4</INF>H<INF>8</INF>)<INF>n</INF>(C<INF>5</INF>H<INF>7.31</INF>Cl
<INF>0.69</INF>)<INF>m</INF> (chloro-isobutene-isoprene rubber) +
(0.69m) NaCl + (0.69m) H<INF>2</INF>O
(8) Tax rate calculated by Petitioner, based on Petitioner's
conversion factors for taxable chemicals used in production of
substance:
(i) Tax rate: $9.46 per ton.
(ii) Conversion factors: 0.96 for butylene, 0.02 for chlorine, 0.01
for sodium hydroxide.
(9) Public docket number: IRS-2025-0137.
Michael Beker,
Senior Counsel (Energy, Credits, and Excise Tax), IRS Office of Chief
Counsel.
[FR Doc. 2025-15564 Filed 8-14-25; 8:45 am]
BILLING CODE 4830-01-P
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