Superfund Tax on Chemical Substances; Request To Modify List of Taxable Substances; Notice of Filing for Acrylonitrile-butadiene Rubber; x=3,344.33, y=1,335.09, a=2.98
This notice of filing announces that a petition has been filed requesting that acrylonitrile-butadiene rubber ((C<INF>4</INF>H<INF>6</INF>)<INF>x</INF>- (C<INF>3</INF>H<INF>3</I...
This notice of filing announces that a petition has been filed requesting that acrylonitrile-butadiene rubber ((C4
H6)x
-(C3
H3
N)y
-(C25
H44
OS2)a; x=3,344.33, y=1,335.09, a=2.98), also known as “NBR,” 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 November 9, 2026.
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
www.regulations.gov
(indicate public docket number IRS-2026-1029 or acrylonitrile-butadiene rubber; x=3,344.33, y=1,335.09, a=2.98) 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 Comments cannot be edited or withdrawn once submitted to the Federal eRulemaking Portal.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 acrylonitrile-butadiene rubber; x=3,344.33, y=1,335.09, a=2.98), 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
www.regulations.gov,
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:
Jacob W. Peeples 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 NBR be added to the list of taxable substances under section 4672(a) of the Internal Revenue Code (List). The petition requesting the addition of NBR 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.
(2)
Petitioner:
Zeon Chemicals L.P. is an importer and exporter of NBR.
(3)
Proposed classification numbers:
(i)
HTSUS number:
4002.59.0000.
(ii)
Schedule B number:
4002.59.0000.
(iii)
CAS number:
9003-18-3, 8.
(4)
Petition filing dates:
(i)
Petition filing date for purposes of making a determination:
November 21, 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:
NBR is an oil-resistant synthetic rubber produced from a copolymer of acrylonitrile and butadiene. Its main applications are in fuel hoses, gaskets, rollers, and other products in which oil resistance is required. NBR is made from butadiene, propylene, ammonia, benzene, methane, and sodium hydroxide. Taxable chemicals constitute 79.51 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 NBR is through emulsion polymerization of butadiene and acrylonitrile. Emulsion polymerization involves application of emulsifier to emulsify hydrophobic polymers through aqueous phase by amphipathic emulsifier, then generation of free radicals with either a water or oil soluble initiators. It is characterized by reduction of bimolecular termination of free radicals due to segregation of free radicals among the discrete monomer-swollen polymer particles.
The latex particles size ranged from 10 nm to 1,000 nm in a diameter and are generally spherical. A typical of particle consist of 1-10,000 macromolecules, where macromolecule contains about 100-106 monomer units. The polymer latex is coagulated, pressed, and dried to remove moisture. Acrylonitrile monomer is produced by the SOHIO process (
i.e.,
catalytic ammoxidation of propylene). Phenol, 2-methyl-4,6-bis[(octylthio)methyl] is produced by reacting o-cresol, 1-octanethiol, and formaldehyde. o-Cresol is produced from the methylation of phenol using methanol. Phenol is produced via the Hock process (
i.e.,
the partial oxidation of cumene via the Hock rearrangement). Cumene is produced via the Friedel-Crafts alkylation of benzene with propylene. Methanol is made from syngas. Hydrogen is produced from steam-methane reforming. 1-Octanethiol is produced by from halogen substituted octane and sodium hydrosulfide. Halogen substituted octane is produced by reacting octane and a halogen (
e.g.,
iodine). Sodium hydrosulfide is produced by the reaction of sodium hydroxide with hydrogen sulfide. Formaldehyde is produced by the catalytic oxidation of methanol.
(7)
Stoichiometric material consumption equation, based on process identified as predominant method of production:
x C4
H6
(butadiene) + y [C3
H6
(propylene) + NH3
(ammonia) +
3/2
O2] + a [C6
H6
(benzene) + C3
H6
(propylene) +
3/2
CH4
(methane) + 2 NaOH (sodium hydroxide) + 2 O2
(oxygen) + 3 CO (syngas) + 2 C8
H18
(octane) + 2 I2
(iodine) + 2 H2
S (hydrogen sulfide)] → (C4
H6)x
-(C3
H3
N)y
-(C25
H44
OS2)a
(NBR) + a C3
H6
O (acetone) +
3/2
a CO2
+ (3y+4a) H2
O + 2a HI + 2a NaI.
(8)
Tax rate calculated by Petitioner, based on Petitioner's conversion factors for taxable chemicals used in production of substance:
(i)
Tax rate:
$9.54 per ton.
(ii)
Conversion factors:
0.71 for butadiene, 0.22 for propylene, 0.09 for
( printed page 57451)
ammonia, 0.0009 for benzene, 0.0003 for methane, and 0.0009 for sodium hydroxide.
(9)
Public docket number:
IRS-2026-1029.
Michael H. Beker,
Senior Counsel (Energy, Credits, and Excise Tax), IRS Office of Chief Counsel.
Use this for formal legal and research references to the published document.
91 FR 57450
Web Citation
Suggested Web Citation
Use this when citing the archival web version of the document.
“Superfund Tax on Chemical Substances; Request To Modify List of Taxable Substances; Notice of Filing for Acrylonitrile-butadiene Rubber; x=3,344.33, y=1,335.09, a=2.98,” thefederalregister.org (September 9, 2026), https://thefederalregister.org/documents/2026-18268/superfund-tax-on-chemical-substances-request-to-modify-list-of-taxable-substances-notice-of-filing-for-acrylonitrile-but.
www.regulations.gov