EPA Final Rule: Dimethylpolysiloxane Pesticide Exemption

Content

ACTION:

Final rule.

SUMMARY:

This regulation establishes an exemption from the requirement of a tolerance for residues of methyl end-capped polydimethylsiloxane
(CAS Reg. No 63148-62-9); also known as dimethylpolysiloxane when used as an inert ingredient in a pesticide chemical formulation
under 40 CFR 180.960. Momentive Performance Materials, Inc submitted a petition to EPA under the Federal Food, Drug, and Cosmetic
Act (FFDCA), requesting an exemption from the requirement of a tolerance. This regulation eliminates the need to establish
a maximum permissible level for residues of methyl end-capped polydimethylsiloxane on food or feed commodities when used in
accordance with these exemptions.

DATES:

This regulation is effective March 25, 2026. Objections and requests for hearings must be received on or before May 26, 2026
and must be filed in accordance with the instructions provided in 40 CFR part 178 (see also Unit I.C. of this document).

ADDRESSES:

The docket for this action, identified by docket identification (ID) number EPA-HQ-OPP-2024-0109, is available online at https://www.regulations.gov. Additional information about dockets generally, along with instructions for visiting the docket in-person, is available at https://www.epa.gov/ dockets.

FOR FURTHER INFORMATION CONTACT:

Charles Smith, Registration Division (7505T), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania
Ave. NW, Washington, DC 20460-0001; main telephone number: (202) 566-1030; email address: RDFRNotices@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

You may be potentially affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer.
The following list of North American Industrial Classification System (NAICS) codes is not intended to be exhaustive, but
rather provides a guide to help readers determine whether this document applies to them. Potentially affected entities may
include:

• Crop production (NAICS code 111).
• Animal production (NAICS code 112).
• Food manufacturing (NAICS code 311).
• Pesticide manufacturing (NAICS code 32532). If you have any questions regarding the applicability of this proposed action to a particular entity, consult the person listed under FOR FURTHER INFORMATION CONTACT .

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

EPA is issuing this rulemaking under section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a. FFDCA
section 408(c)(2)(A)(i) allows EPA to establish an exemption from the requirement for a tolerance (the legal limit for a pesticide
chemical residue in or on a food) only if EPA determines that the exemption is “safe.” FFDCA section 408(c)(2)(A)(ii) defines
“safe” to mean that “there is a reasonable certainty that no harm will result from aggregate exposure to the pesticide chemical
residue, including all anticipated dietary exposures and all other exposures for which there is reliable information.” This
includes exposure through drinking water and in residential settings but does not include occupational exposure. Pursuant
to FFDCA section 408(c)(2)(B), in establishing or maintaining in effect an exemption from the requirement of a tolerance,
EPA must take into account the factors set forth in FFDCA section 408(b)(2)(C), which require EPA to give special consideration
to exposure of infants and children to the pesticide chemical residue in establishing a tolerance and to “ensure that there
is a reasonable certainty that no harm will result to infants and children from aggregate exposure to the pesticide chemical
residue . . . .” Additionally, FFDCA section 408(b)(2)(D) requires that the Agency consider, among other things, “available
information concerning the cumulative effects of a particular pesticide's residues” and “other substances that have a common
mechanism of toxicity.”

C. How can I file an objection or hearing request?

Under FFDCA section 408(g), 21 U.S.C. 346a(g), any person may file an objection to any aspect of this regulation and may also
request a hearing on those objections. If you fail to file an objection

  to the final rule within the time period specified in the final rule, you will have waived the right to raise any issues resolved
  in the final rule. You must file your objection or request a hearing on this regulation in accordance with the instructions
  provided in 40 CFR part 178. To ensure proper receipt by EPA, you must identify the docket ID number EPA-HQ-OPP-2024-0109
  in the subject line on the first page of your submission. All objections and requests for a hearing must be in writing and
  must be received by the Hearing Clerk on or before May 26, 2026.

EPA's Office of Administrative Law Judges (OALJ), in which the Hearing Clerk is housed, urges parties to file and serve documents
by electronic means only, notwithstanding any other particular requirements set forth in other procedural rules governing
those proceedings. See “Order Urging Electronic Filing and Service,” dated December 3, 2025, which can be found at https://www.epa.gov/system/files/documents/2025-12/2025-12-03-order-urging-electronic-filing-and-service.pdf.

Although EPA's regulations require submission via U.S. Mail or hand delivery, EPA intends to treat submissions filed via electronic
means as properly filed submissions; therefore, EPA believes the preference for submission via electronic means will not be
prejudicial. When submitting documents to the OALJ electronically, a person should utilize the OALJ e-filing system at https://yosemite.epa.gov/oa/eab/eab-alj_upload.nsf.

In addition to filing an objection or hearing request with the Hearing Clerk as described in 40 CFR part 178, please submit
a copy of the filing (excluding any Confidential Business Information (CBI)) for inclusion in the public docket at https://www.regulations.gov. Follow the online instructions for submitting comments. Do not submit electronically any information you consider to be CBI
or other information whose disclosure is restricted by statute. If you wish to include CBI in your request, please follow
the applicable instructions at https://www.epa.gov/dockets/commenting-epa-dockets#rules and clearly mark the information that you claim to be CBI. Information not marked confidential pursuant to 40 CFR part 2 may
be disclosed publicly by EPA without prior notice.

II. Petition for Exemption

In the
Federal Register
of March 22, 2024 (89 FR 20410) (FRL-11682-02-OCSPP), EPA issued a document pursuant to FFDCA section 408, 21 U.S.C. 346a,
announcing the receipt of a pesticide petition (PP IN-11844) filed by Momentive Performance Materials, Inc, 2750 Balltown
Road, Niskayuna, NY 12309. The petition requested that 40 CFR 180.960 be amended by changing (lowering) the minimum number
average molecular weight for methyl end-capped polydimethylsiloxane to 1200 amu; CAS Reg. No 63148-62-9. That document included
a summary of the petition prepared by the petitioner, which is available in the docket. The Agency received 3 public comments.
All 3 comments were in support of this inert ingredient approval.

III. Inert Ingredient Definition

Inert ingredients are all ingredients that are not active ingredients as defined in 40 CFR 153.125 and include, but are not
limited to, the following types of ingredients (except when they have a pesticidal efficacy of their own): Solvents such as
alcohols and hydrocarbons; surfactants such as polyoxyethylene polymers and fatty acids; carriers such as clay and diatomaceous
earth; thickeners such as carrageenan and modified cellulose; wetting, spreading, and dispersing agents; propellants in aerosol
dispensers; microencapsulating agents; and emulsifiers. The term “inert” is not intended to imply nontoxicity; the ingredient
may or may not be chemically active. Generally, EPA has exempted inert ingredients from the requirement of a tolerance based
on the low toxicity of the individual inert ingredients.

IV. Aggregate Risk Assessment and Determination of Safety

EPA establishes exemptions from the requirement of a tolerance only in those cases where it can be shown that the risks from
aggregate exposure to pesticide chemical residues under reasonably foreseeable circumstances will pose no appreciable risks
to human health. In order to determine the risks from aggregate exposure to pesticide inert ingredients, the Agency considers
the toxicity of the inert in conjunction with possible exposure to residues of the inert ingredient through food, drinking
water, and through other exposures that occur as a result of pesticide use in residential settings. If EPA is able to determine
that a finite tolerance is not necessary to ensure that there is a reasonable certainty that no harm will result from aggregate
exposure to the inert ingredient, an exemption from the requirement of a tolerance may be established.

Consistent with FFDCA section 408(b)(2)(D), EPA has reviewed the available scientific data and other relevant information
in support of this action. EPA has sufficient data to assess the hazards of and to make a determination on aggregate exposure
for methyl end-capped polydimethylsiloxane including exposure resulting from the exemption established by this action. EPA's
assessment of exposures and risks associated with methyl end-capped polydimethylsiloxane follows.

A. Low Risk Polymer Criteria

In the case of certain chemical substances that are defined as polymers, the Agency has established a set of criteria to identify
categories of polymers expected to present minimal or no risk. The definition of a polymer is given in 40 CFR 723.250(b) and
the exclusion criteria for identifying these low-risk polymers are described in 40 CFR 723.250(d). Methyl end-capped polydimethylsiloxane
conforms to the definition of a polymer given in 40 CFR 723.250(b) and meets the following criteria that are used to identify
low-risk polymers.

1. The polymer is not a cationic polymer nor is it reasonably anticipated to become a cationic polymer in a natural aquatic
   environment.

2. The polymer does contain as an integral part of its composition at least two of the atomic elements carbon, hydrogen, nitrogen,
   oxygen, silicon, and sulfur.

3. The polymer does not contain as an integral part of its composition, except as impurities, any element other than those
   listed in 40 CFR 723.250(d)(2)(ii).

4. The polymer is neither designed nor can it be reasonably anticipated to substantially degrade, decompose, or depolymerize.
   A provided referenced publication shows that the cyclic monomers and short chain linear siloxanes are not readily biodegradable
   by OECD 301 test methods.

5. The polymer is manufactured or imported from monomers and/or reactants that are already included on the TSCA Chemical Substance
   Inventory or manufactured under an applicable TSCA section 5 exemption.

6. The polymer is not a water absorbing polymer with a number average molecular weight (MW) greater than or equal to 10,000
   Daltons.

7. The polymer does not contain certain perfluoroalkyl moieties consisting of a CF3- or longer chain length as listed in 40
   CFR 723.250(d)(6). Additionally, the polymer also meets as required the following exemption criteria: specified in 40 CFR
   723.250(e):

The polymer's number average MW of 1200 Daltons is greater than 1,000 and less than 10,000 Daltons. The polymer

  contains less than 10% oligomeric material below MW 500 and less than 25% oligomeric material below MW 1,000, and the polymer
  does not contain any reactive functional groups.

Thus, methyl end-capped polydimethylsiloxane meets the criteria for a polymer to be considered low risk under 40 CFR 723.250.
Based on its conformance to the criteria in this unit, no mammalian toxicity is anticipated from dietary, inhalation, or dermal
exposure to methyl end-capped polydimethylsiloxane.

B. Exposure Assessment

For the purposes of assessing potential exposure under this exemption, EPA considered that methyl end-capped polydimethylsiloxane
could be present in all raw and processed agricultural commodities and drinking water, and that non-occupational non-dietary
exposure was possible. The minimum number average MW of methyl end-capped polydimethylsiloxane is 1,200 Daltons. Generally,
a polymer of this size would be poorly absorbed through the intact gastrointestinal tract or through intact human skin. Since
methyl end-capped polydimethylsiloxane conform to the criteria that identify a low-risk polymer, there are no concerns for
risks associated with any potential exposure scenarios that are reasonably foreseeable. The Agency has determined that a tolerance
is not necessary to protect the public health.

C. Cumulative Effects From Substances With a Common Mechanism of Toxicity

Section 408(b)(2)(D)(v) of FFDCA requires that, when considering whether to establish, modify, or revoke a tolerance, the
Agency consider “available information” concerning the cumulative effects of a particular pesticide's residues and “other
substances that have a common mechanism of toxicity.”

EPA has not found methyl end-capped polydimethylsiloxane to share a common mechanism of toxicity with any other substances,
and methyl end-capped polydimethylsiloxane does not appear to produce a toxic metabolite produced by other substances. For
the purposes of this tolerance exemption, therefore, EPA has assumed that methyl end-capped polydimethylsiloxane does not
have a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals
have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see EPA's website at https://www.epa.gov/pesticide-science-and-assessing-pesticide-risks/cumulative-assessment-risk-pesticides.

D. Additional Safety Factor for the Protection of Infants and Children

Section 408(b)(2)(C) of FFDCA provides that EPA shall apply an additional tenfold (10X) margin of safety for infants and children
in the case of threshold effects to account for prenatal and postnatal toxicity and the completeness of the database on toxicity
and exposure unless EPA determines based on reliable data that a different margin of safety will be safe for infants and children.
Due to the expected low toxicity of methyl end-capped polydimethylsiloxane, EPA has not used a safety factor analysis to assess
the risk. For the same reasons no additional safety factor is needed for assessing risk to infants and children.

E. Determination of Safety

Based on the conformance to the criteria used to identify a low-risk polymer, EPA concludes that there is a reasonable certainty
of no harm to the U.S. population, including infants and children, from aggregate exposure to residues of methyl end-capped
polydimethylsiloxane.

F. Analytical Enforcement Methodology

An analytical method is not required for enforcement purposes since the Agency is establishing an exemption from the requirement
of a tolerance without any numerical limitation.

G. Conclusion

Accordingly, EPA finds that exempting residues of methyl end-capped polydimethylsiloxane from the requirement of a tolerance
will be safe.

V. Statutory and Executive Order Reviews

Additional information about these statutes and Executive Orders can be found at https://www.epa.gov/regulations/and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review

This action is exempt from review under Executive Order 12866 (58 FR 51735, October 4, 1993), because it establishes or modifies
a pesticide tolerance or a tolerance exemption under FFDCA section 408.

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

Executive Order 14192 (90 FR 9065, February 6, 2025) does not apply because actions that establish a tolerance under FFDCA
section 408 are exempted from review under Executive Order 12866.

C. Paperwork Reduction Act (PRA)

This action does not impose an information collection burden under the PRA 44 U.S.C. 3501 et seq., because it does not contain any information collection activities.

D. Regulatory Flexibility Act (RFA)

This action is not subject to the RFA, 5 U.S.C. 601 et seq. The RFA applies only to rules subject to notice and comment rulemaking requirements under the Administrative Procedure Act
(APA), 5 U.S.C. 553, or any other statute. This rule is not subject to the APA but is subject to FFDCA section 408(d), which
does not require notice and comment rulemaking to take this action in response to a petition.

E. Unfunded Mandates Reform Act (UMRA)

This action does not contain an unfunded mandate of $100 million or more (in 1995 dollars and adjusted annually for inflation)
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 as specified in Executive Order 13132 (64 FR 43255, August 10, 1999), because
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 (65 FR 67249, November 9, 2000), because
it will not have substantial direct effects on tribal governments, on the relationship between the Federal government and
the Indian tribes, or on the distribution of power and responsibilities between the Federal government and Indian tribes.

H. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

This action is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it is not a significant regulatory
action under section 3(f)(1) of Executive Order 12866 (See Unit V.A.), and because EPA does not believe the environmental
health or safety risks

  addressed by this action present a disproportionate risk to children. However, EPA's 2021 *Policy on Children's Health* applies to this action.

This rule finalizes tolerance actions under the FFDCA, which requires EPA to give special consideration to exposure of infants
and children to the pesticide chemical residue in establishing a tolerance and to “ensure that there is a reasonable certainty
that no harm will result to infants and children from aggregate exposure to the pesticide chemical residue . . .” (FFDCA 408(b)(2)(C)).
The Agency's consideration is documented in the pesticide-specific registration review documents, located in the applicable
docket at https://www.regulations.gov.

I. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution or Use

This action is not subject to Executive Order 13211 (66 FR 28355) (May 22, 2001) because it is not a significant regulatory
action under Executive Order 12866.

J. National Technology Transfer Advancement Act (NTTAA)

This action does not involve technical standards that would require Agency consideration under NTTAA section 12(d), 15 U.S.C.
272.

K. Congressional Review Act (CRA)

This action is subject to the CRA, 5 U.S.C. 801 et seq., and EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. This
action is not a “major rule” as defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

Environmental protection, Administrative practice and procedure, Agricultural commodities, Pesticides and pests, Reporting
and recordkeeping requirements.

Dated: March 19, 2026. Charles Smith, Director, Registration Division, Office of Pesticide Programs. For the reasons stated in the preamble, 40 CFR chapter I is amended as follows:

PART 180—[AMENDED]

Regulatory Text 1. The authority citation for part 180 continues to read as follows:

Authority:

21 U.S.C. 321(q), 346a and 371.

1. Amend § 180.960, in Table 1 to § 180.960 by revising the entry for “Dimethylpolysiloxane minimum number average molecular weight (in amu), 6,800” to read as follows:

§ 180.960 Polymers; exemptions from the requirement of a tolerance.

---

| Polymer | CAS No. |
| --- | --- |
| | |
|                                                       * | |
| Dimethylpolysiloxane, minimum number average molecular weight (in amu), 1,200 | 63148-62-9 |
| | |
|                                                       * | |
[FR Doc. 2026-05773 Filed 3-24-26; 8:45 am] BILLING CODE 6560-50-P

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