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EPA REGISTRATION DIVISION COMPANY NOTICE OF FILING FOR 

PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER 

EPA Registration Division contact: [insert name and telephone number with area 

code] 

INSTRUCTIONS: Please utilize this outline in preparing the pesticide petition. In 

cases where the outline element does not apply, please insert “NA-Remove” and 

maintain the outline. Please do not change the margins, font, or format in your 

pesticide petition. Simply replace the instructions that appear in green, i.e., “[insert 

company name],” with the information specific to your action.

TEMPLATE: 

Wacker Chemical Corporation

[Insert petition number]

 EPA has received a pesticide petition (PP 9E7634) from Wacker Chemical 

Corporation, 3301 Sutton Rd., Adrian, MI. 49221-9397 proposing, pursuant to section 

408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to 

amend 40 CFR part 180. 

2. to establish an exemption from the requirement of a tolerance for

 Tetraethoxysilane, polymer with hexamethyldisiloxane with a minimum 

number average molecular weight of (in AMU) of 2,500 CAS Number 104133-09-7 

in or on the all raw agricultural commodities . EPA has determined that the petition 

contains data or information regarding the elements set forth in section 408 (d)(2) of 

FDDCA; however, EPA has not fully evaluated the sufficiency of the submitted data at 

this time or whether the data supports granting of the petition. Additional data may be 

needed before EPA rules on the petition. 

A. Residue Chemistry NA-Remove

Requirements for data on residue chemistry are not applicable to a request to 

establish an exemption from requirement of a tolerance, based on conformance to 

specific criteria that identify categories of polymers that should present minimal or 

no risk

 1. Plant metabolism. NA-Remove

 2. Analytical method. NA-Remove
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 3. Magnitude of residues. NA-Remove

B. Toxicological Profile NA-Remove

Requirements for data on Toxicological properties are not applicable to a request to 

establish an exemption from requirement of a tolerance, based on conformance to 

specific criteria that identify categories of polymers that should present minimal or 

no risk

Tetraethoxysilane, polymer with hexamethyldisiloxane, minimum number average 

molecular weight (in AMU) 2,500 conforms to the definition of a polymer given in 

40 CFR 723(b) and meets the criteria that are used to identify low risk polymers. 

under the TSCA Polymer Exemption Guidelines. 

1. The polymer is not a cationic polymer nor is it reasonably anticipated to become a 

cationic polymer in the aquatic environment. 

Justification: Tetraethoxysilane, polymer with hexamethyldisiloxane contains no 

cationic functional groups, nor any moiety that can potentially produce a cationic 

group. 

2. The polymer does contain as an integral part of its composition the atomic 

elements carbon, hydrogen, oxygen and silicon. 

Justification: Tetraethoxysilane, polymer with hexamethyldisiloxane contains four 

of the permitted elements (carbon, hydrogen, nitrogen, oxygen, sulfur and silicon), 

and does not contain any of the elements of concern (fluoride, lithium, boron, 

phosphorus, etc.). 

3. The polymer does not contain as an integral part of its composition except as 

impurities, any element other than those listed in 40CFR 723.250(d)(2)(ii). 

Justification: Tetraethoxysilane, polymer with hexamethyldisiloxane is produced by 

reacting two compounds Tetatraethoxy silane (AKA Tetraethyl silicate) with a 

molecular formula C8H20O4Si with Hexamethyldisiloxane with a molecular 

formula C6H18OSi2. Neither starting material contains, except as impurites, any 

elements not listed in 40CFR 723.250(d)(2)(ii). 

4. The polymer is neither designed nor can it be reasonably anticipated to 

substantially degrade, decompose or depolymerize. 

Justification: Tetraethoxysilane, polymer with hexamethyldisiloxane contains only 

H-C, C-Si, C-O and Si-O bonds, none of which are unstable (as evidenced by the 

known stability of polysiloxanes and silicones) and therefore the polymer will be 

stable. 
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5. The polymer is manufactured or imported from monomers and or reactants that 

are already listed on the TSCA Chemical Substance Inventory or manufactured 

under and applicable TSCA Section 5 exemption. 

Justification: Tetraethoxy silane CAS Number 78-10-4 and Hexamethyldisiloxane 

CAS Number 107-46-0 are both listed on the TSCA Inventory. 

6. The polymer is not a water-absorbing polymer with a minimum number average 

molecular weight greater than or equal to 10,000 AMU. 

Justification: The polymer is non-ionic, does not contain any significant hydrophilic 

groups and like most silicone resins is expected to be relatively hydrophobic. The 

number average molecular weight is only 2,500 AMU which is well under the 10,000 

AMU upper limit. 

7. Tetraethoxysilane, polymer with hexamethyldisiloxane meets the criteria specified 

in 40CFR 723.250(e)(1). 

Justification: The minimum number average molecular weight (Mn) of the polymer 

is greater than 1000 AMU but less than 10,000 AMU. The weight fraction less than 

500 AMU is less than 10% and the weight fraction less than 1,000 AMU is less than 

25%. 

This polymer is already listed in 40CFR 180.960, but with a higher minimum 

number average molecular weight limit (6,500 AMU). At our proposed lower (Mn) 

of limit of 2,500 this polymer would still meet all of the criteria for a polymer to be 

considered low risk under 40CFR 723.250. Based on its conformance to these 

criteria no mammalian toxicity is anticipated from dietary ingestion, inhalation or 

dermal exposure to Tetraethoxysilane, polymer with hexamethyldisiloxane . 

 1. Acute toxicity. NA- Remove

 2. Genotoxicty. NA-Remove

 3. Reproductive and developmental toxicity. NA-Remove

 4. Subchronic toxicity. NA-Remove

 5. Chronic toxicity. NA-Remove]

 6. Animal metabolism. NA-Remove

 7. Metabolite toxicology. NA-Remove

 8. Endocrine disruption. NA-Remove
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C. Aggregate Exposure 

 For the purposes of assessing potential exposure under this exemption, 

Tetraethoxysilane, polymer with hexamethyldisiloxane could be considered to be 

present in all raw and processed agricultural commodities and drinking water, and 

non-occupational non-dietary exposure is possible. The minimum number average 

molecular weight of Tetraethoxysilane, polymer with hexamethyldisiloxane is 2,500 

AMU. Generally, a polymer of this size would be poorly absorbed through the intact 

gastrointestinal tract or through intact human skin. Since Tetraethoxysilane, 

polymer with hexamethyldisiloxane conforms to the criteria that identify a low risk 

polymer, there should be no concerns for risks associated with any reasonably 

foreseeable potential exposure scenarios. A tolerance should not be necessary to 

protect public health.

 1. Dietary exposure. NA-Remove

 i. Food. NA-Remove

 ii. Drinking water. NA-Remove

 2. Non-dietary exposure. NA-Remove

D. Cumulative Effects

 Section 408(b)(2)(D)(v) of FFDCA requires that, when considering whether 

to establish, modify, or revoke a tolerance or tolerance exemption, the Agency 

consider "available information" concerning the cumulative effects of a particular 

chemical's residues and "other substances that have a common mechanism of 

toxicity.". Wacker Chemical Corporation does not have any available data 

indicating that Tetraethoxysilane, polymer with hexamethyldisiloxane has a 

common mechanism of toxicity with other substances Tetraethoxysilane, polymer 

with hexamethyldisiloxane is also not likely to produce any toxic metabolite 

produced by other substances. For the purposes of this tolerance exemption 

Tetraethoxysilane, polymer with hexamethyldisiloxane should not be assumed to 

have a common mechanism of toxicity with other substances.

E. Safety Determination

 1. U.S. population. NA-Remove

 2. Infants and children. Section 408 of FFDCA provides that EPA shall apply 

an additional tenfold margin of safety for infants and children in the case of 

threshold effects to account for pre-natal and post-natal toxicity and the 

completeness of the data base unless EPA concludes that a different margin of safety 

will be safe for infants and children. Due to the expected low toxicity of 

Tetraethoxysilane, polymer with hexamethyldisiloxane a safety factor analysis to 
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assess specific risk to infants and children should not be required. For the same 

reasons the additional tenfold safety factor is unnecessary.

F. International Tolerances

 Wacker Chemical Corporation is not aware of any country requiring a 

tolerance for Tetraethoxysilane, polymer with hexamethyldisiloxane nor have any 

CODEX Maximum Residue Levels (MRLs) been established for any food crops at 

this time,