Document ID: EPA-HQ-OPP-2006-0229-0001
Agency: epa
Document Type: Rule
Title: Potassium Silicate; Exemption from the Requirement of a Tolerance
Posted Date: 2022-08-12T04:00Z

[Federal Register: June 14, 2006 (Volume 71, Number 114)]
[Rules and Regulations]               
[Page 34267-34272]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14jn06-15]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2006-0299; FRL-8069-6]

 
Potassium Silicate; Exemption from the Requirement of a Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes an exemption from the requirement 
of a tolerance for residues of potassium silicate in or on all food 
commodities when applied/used as a fungicide, insecticide or miticide 
so long as the potassium silicate is not applied at rates exceeding 1% 
by weight in aqueous solution and when used in accordance with good 
agricultural practices. PQ Corporation submitted a petition to EPA 
under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by 
the Food Quality Protection Act of 1996 (FQPA), requesting an exemption 
from the requirement of a tolerance. This regulation eliminates the 
need to establish a maximum permissible level for residues of potassium 
silicate.

DATES: This regulation is effective June 14, 2006. Objections and 
requests for hearings must be received on or before August 14, 2006, 
and must be filed in accordance with the instructions provided in 40 
CFR part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION.

ADDRESSES:  EPA has established a docket for this action under docket 
identification (ID) number EPA-HQ-OPP-2006-0299. All documents in the 
docket are listed in the index for the docket. Although listed in the 
index, some information is not publicly available, e.g., Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Certain other material, such as copyrighted 
material, is not placed on the Internet and will be publicly available 
only in hard copy form. Publicly available docket materials are 
available in the electronic docket at http://www.regulations.gov, or, 

if only available in hard copy, at the OPP Regulatory Public Docket in 
Rm. S-4400, One Potomac Yard (South Building), 2777 S. Crystal Drive, 
Arlington, VA. The Docket Facility is open from 8:30 a.m. to 4 p.m., 
Monday through Friday, excluding legal holidays. The telephone number 
for the Docket is (703) 305-5805.

FOR FURTHER INFORMATION CONTACT: Carol E. Frazer, Biopesticides and 
Pollution Prevention Division (7511P), Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 308-8810; e-mail address: frazer.carol@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. 
Potentially affected entities may include, but are not limited to:
     Crop production (NAICS code 111).
     Animal production (NAICS code 112).
     Food manufacturing (NAICS code 311).
     Pesticide manufacturing (NAICS code 32532).
     This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in this unit could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain entities. If you have any 
questions regarding the applicability of this action to a particular 
entity, consult the person listed under FOR FURTHER INFORMATION 
CONTACT.

B. How Can I Access Electronic Copies of this Document?

    In addition to accessing an electronic copy of this Federal 
Register document through the electronic docket at http://www.regulations.gov
, you may access this Federal Register document 

electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr. You may also access a 

frequently updated electronic version of 40 CFR part 180 through the 
Government Printing Office's pilot e-CFR site at http://www.gpoaccess.gov/ecfr
.

C. Can I File an Objection or Hearing Request?

    Under section 408(g) of FFDCA, as amended by the FQPA, any person 
may file an objection to any aspect of this regulation and may also 
request a hearing on those objections. The EPA procedural regulations 
which govern the submission of objections and requests for hearings 
appear in 40 CFR part 178. You must file your objection or request a 
hearing on this regulation in accordance with the instructions

[[Page 34268]]

provided in 40 CFR part 178. To ensure proper receipt by EPA, you must 
identify docket ID number EPA-HQ-OPP-2006-0299 in the subject line on 
the first page of your submission. All requests must be in writing, and 
must be mailed or delivered to the Hearing Clerk on or before August 
14, 2006.
    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 that does not contain any CBI for inclusion in the public 
docket that is described in ADDRESSES. Information not marked 
confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA 
without prior notice. Submit your copies, identified by docket ID 
number EPA-HQ-OPP-2006-0299, by one of the following methods:
     Federal eRulemaking Portal: http://www.regulations.gov. 

Follow the on-line instructions for submitting comments.
     Mail: Office of Pesticide Programs (OPP) Regulatory Public 
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460-0001.
     Delivery: OPP Regulatory Public Docket (7502P), 
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South 
Building), 2777 S. Crystal Drive, Arlington, VA. Deliveries are only 
accepted during the Docket's normal hours of operation (8:30 a.m. to 4 
p.m., Monday through Friday, excluding legal holidays). Special 
arrangements should be made for deliveries of boxed information. The 
telephone number for the Docket is (703) 305-5805.

II. Background and Statutory Findings

    In the Federal Register of July 27, 2005 (70 FR 43417) (FRL-7719-
5), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 
U.S.C. 346a(d)(3), announcing the filing of a pesticide tolerance 
petition (PP 5F6905) by PQ Corporation, P.O. Box 840 Valley Forge, PA 
19482-0840. The petition requested that 40 CFR part 180 be amended by 
establishing a temporary exemption from the requirement of a tolerance 
for residues of potassium silicate. This notice included a summary of 
the petition prepared by the petitioner PQ Corporation. There were no 
comments received in response to the notice of filing.
    Section 408(c)(2)(A)(I) of FFDCA 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.'' Section 408(c)(2)(A)(ii) of FFDCA 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 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 
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, section 408(b)(2)(D) of FFDCA requires that 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 performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. First, EPA determines the 
toxicity of pesticides. Second, EPA examines exposure to the pesticide 
through food, drinking water, and through other exposures that occur as 
a result of pesticide use in residential settings.

III. Toxicological Profile

    Consistent with section 408(b)(2)(D) of FFDCA, EPA has reviewed the 
available scientific data and other relevant information in support of 
this action and considered its validity, completeness, and reliability 
and the relationship of this information to human risk. EPA has also 
considered available information concerning the variability of the 
sensitivities of major identifiable subgroups of consumers, including 
infants and children.
    Potassium silicate is a synthetic compound that is chemically the 
potassium salt of silicic acid. It is produced by combining pure silica 
sand (SiO2) and potash (K2CO3 or 
NaCO3). Silicic acid salts (i.e., silicates) are the most 
common form of silicon. For the purposes of this tolerance exemption, 
the Agency has relied on the extensive body of knowledge, data and/or 
information from the public literature as submitted by PQ Corporation 
and as researched by the Agency which document the similarity of silica 
(also known as silicon dioxide) and potassium silicate and support the 
conclusion that there is reasonable certainty of no harm that will 
result from the use of potassium silicate as an agricultural pesticide.
    Silicon dioxide (silica) has been assessed for its pesticidal uses 
by the Agency and it was determined that the toxicity of this compound 
is moderate to low and therefore, the human health risk is low and not 
unreasonable. Further, silicon dioxide is recognized by the Food and 
Drug Administration (FDA) to be a Generally-Recognized As Safe (GRAS) 
substance, as a food additive (21 CFR 182.90 and 182.1711).
    Comprehensive reviews and risk assessments have been conducted on 
silicon dioxide (silica) and its related soluble silicates with regard 
to its toxicity to human health and have concluded that silica and its 
soluble silicates (potassium silicate) are low in toxicity and the 
primary hazard of concern is the corrosive nature of the compound. The 
corrosive nature of potassium silicate is not of a concern when used as 
a very dilute solution (less than or equal to 1%). The soluble 
silicates include: potassium silicate, sodium silicate and sodium 
metasilicate, the latter of which the Agency has exempted in diluted 
form from the requirement of a tolerance for use on all food 
commodities. Additionally, the FDA has determined that sodium silicate 
and potassium silicate can be used interchangeably which substantiates 
information in the public literature that the compounds are very 
similar.
    The data submitted and reviewed on the end use pesticide product 
containing 29.1% w/w potassium silicate caused moderate to low dermal 
irritation and is classified as an eye irritant due to the high pH of 
the product. When used as a pesticide (fungicide, insecticide and 
miticide) the active ingredient is effective at very low concentrations 
(less than or equal to 1%) and thus the dilution of the active 
ingredient would reduce the risks to pesticide users. Labeling of such 
products with the appropriate protective clothing, gloves and eyewear 
would mitigate the risk of exposure to potassium silicate on pesticide 
applicators. Potassium silicate residues which may result from its use 
as an agricultural pesticide would be reduced by washing or processing 
treated commodities before their consumption; this point is supported 
by the water solubility of potassium silicate and the possibility of it 
being washed off treated surfaces by rainfall in the field. Further, 
potassium silicate is neutralized by stomach acid and primarily 
excreted in the urine.

[[Page 34269]]

    The components of potassium silicate are potassium and silicon. 
Potassium is found in the environment and is an essential element in 
human and plant nutrition. It is found in many fruits and vegetables 
consumed by humans. A common soil plant nutrient and fertilizer (as 
K2O), potassium comprises approximately 2.59% of the Earth's 
crust by weight. The primary source of naturally-occurring soluble 
potassium is from the weathering of potassium containing minerals.
    Silicon is ubiquitous in the environment, the second most abundant 
element in the lithosphere after oxygen. A nutritional element, silica 
is required for proper and strong growth of mammalian bones. Silica is 
present naturally in all plant stems and is present in larger amounts 
in crops such as rice and sugar cane. It comprises approximately 31% of 
the Earth's crust by weight and is present as dissolved silica, 
amorphous silica in the solid phase (for example, silica and silica gel 
(FDA GRAS chemicals), and silica bound to organic matter. In the normal 
range of soil pH, silicic acid is the major silicate in soil water. In 
natural waters most dissolved silica results from weathering of 
silicate minerals. Research demonstrates that commercial soluble 
silicates rapidly degrade to molecular forms that are indistinguishable 
from natural dissolved silica (IUCLID, 1995). Beach sand, for example 
is comprised of nearly 100% silica (Crop Protection handbook, 2003). 
Additionally, silica is approved by the FDA for use as an anti-caking 
agent in food.
    Potassium silicate immediately breaks down in the presence of water 
to the potassium and silicate ions which are indistinguishable from 
natural components. As stated above, potassium silicate is produced by 
direct fusion of precisely measured portions of pure silica sand 
(SiO2) and potash (K2CO3) in a fired 
furnace at temperatures above 1000[deg]C. Solutions of potassium 
silicate are produced by dissolving alkali silica lumps in water at 
elevated temperatures. Potassium silicate is classified as GRAS by FDA 
(21 CFR 182.90 and 21 CFR 182.1711) for limited use in canned potable 
water as a corrosion inhibiting agent and the EPA has exempted 
potassium silicate from the requirement of a tolerance when used as an 
inert ingredient, a surfactant, emulsifier, wetting agent, stabilizer, 
or inhibitor (40 CFR 180.910). Data and/or information from the public 
literature demonstrates a long history of safe use of fertilizers 
containing potassium and silica. (HERA 2005, NOSB/TAP, 2003 and the 
Silicon Dioxide and Silica Gel RED EPA, 1991, Kant, T., et al, 2003, 
Savant N.K., et al., 1999). Fertilizers used in the agricultural 
industry contain plant nutrients and micronutrients such as potassium 
and silicon. Potassium silicate is approved by the USDA as a fertilizer 
for conventional agriculture and is used on a variety of crops 
including rice, wheat, barley, sugar cane, melons, grapes and cucurbits 
(USDA/ERS, 2002, NOSB/TAP, 2003).
    As mentioned above, silicon dioxide and its soluble silicates which 
include potassium silicate have been fully characterized and assessed 
by the Agency and other notable resources and it has been concluded 
that silicon dioxide and its related soluble silicates exhibit moderate 
to low toxicity, the Agency has therefore concluded there is a 
reasonable certainty of no harm resulting from the use of potassium 
silicate as an agricultural pesticide. This determination is based on 
information from the literature which as stated above document the 
similarity of silica (also known as silicon dioxide) and potassium 
silicate. This information combined with the fact that the components 
of potassium silicate (potassium and silica) are already naturally 
present in the stems of all plants (silica) and naturally in foods 
supports the Agency's conclusion that there is a reasonable certainty 
of no harm resulting from the use of potassium silicate as an 
agricultural pesticide and exposure from the use of potassium silicate 
as a pesticide will not add to the exposure already present from its 
natural occurrence, its presence in foods, in the human diet and in the 
environment.

A. Acute Toxicity

    The registrant did not submit any toxicity data testing the 
technical grade of the active ingredient. Data waivers were requested 
by the registrant and granted by the Agency based on the body of 
extensive knowledge from the public literature and as researched by the 
Agency. The toxicity of the soluble silicates via oral toxicity, 
teratogenicity and genotoxicity were tested on the Technical Grade of 
the Active Ingredient (TGAI) and reported and the Agency has relied 
upon this information to support its decision to grant the waiver 
requests for these studies. Acute toxicity data were submitted using 
the end-use product as the test material which is approximately 
a1/89/21/13/23/87/83/8 dilution of the technical grade of the 
active ingredient. Requests for data waivers were granted for 
additional toxicity studies described below. These data waiver requests 
were granted based on the findings from comprehensive reviews and risk 
assessments conducted on silicon dioxide (silica) and its related 
soluble silicates (potassium silicate) with regard to its toxicity to 
human health and the conclusion that silicon dioxide and its related 
soluble silicates have moderate to low toxicity, and therefore, the 
Agency concludes that there is a reasonable certainty of no harm 
resulting from the use of potassium silicate. The data submitted and 
waivers that were granted are as follows:
    Acute oral rat OPPTS Harmonized Guideline 870.1100; Master Record 
Identification (MRID) Number 46434903). LD50 = 5,000 
milligrams/kilogram (mg/kg) (29.1% potassium silicate aqueous 
solution). The test material is classified as a Toxicity Category IV 
for acute oral toxicity and demonstrates that a dilution of the active 
ingredient to a level that is comparable to the concentration of 
potassium silicate in the proposed end-use product eliminates the 
potential of the active ingredient to cause acute toxic effects. There 
were no adverse effects reported at 5,000 mg/kg.
    Technical grade of the active ingredient. A request to waive this 
data requirement was submitted by the registrant. The Agency has 
granted this data waiver based on: (1) Data from the public literature 
which shows soluble silicates have a moderate to low acute toxicity by 
the oral route (HERA 2005), (2) potassium silicate, a soluble silicate 
that is both chemically and toxicologically similar to silicon dioxide 
(silica) which has been fully characterized, assessed, and therefore 
determined by the Agency that silicon dioxide and its related soluble 
silicates pose no unreasonable adverse effects to human health when 
used as an agricultural pesticide and (3) potassium and silica are 
already present in the human diet as they are contained naturally in 
various crops.
    Acute dermal rat OPPTS 870.1200; (MRID 4643902). LD50 = 
5,000 mg/kg (29.1% potassium silicate aqueous solution). The test 
material is classified as a Toxicity Category IV for acute dermal 
toxicity and demonstrates that a dilution of the active ingredient to a 
level that is comparable to the concentration of potassium silicate in 
the proposed end use product will be moderately irritating to the skin.
    Technical grade of the active ingredient. Section 158.690(c)(2)(I) 
states this test is not required if the test material is corrosive to 
skin. Therefore, this test was not required. However, this active 
ingredient is classified Toxicity Category I on the basis of potential 
dermal irritation effects.

[[Page 34270]]

    Acute inhalation rat OPPTS 870.1300; (MRID 46434906). 
LC50 >2.06 milligrams per liter (mg/L) (29.1% potassium 
silicate aqueous solution). The test material is classified as a 
Toxicity Category IV for acute inhalation toxicity and demonstrates 
that a dilution of the active ingredient to a level that is comparable 
to the concentration of potassium silicate in the proposed end use 
product will not cause acute inhalation effects at greater than 2.06 
mg/L.
    Technical grade of the active ingredient. This test is only 
required if the product consists of a respirable material. Since 
potassium silicate does not consist of a respirable material under 
normal conditions of use, this test is not required.

B. Genotoxicity, Immune Response, Mutagenicity, Developmental, 
Oncogenicity, Subchronic and Chronic Toxicity

    The applicant requested to waive the data requirements below and 
submitted a summary of public literature to satisfy the data 
requirements for 90-day oral toxicity (OPPTS 870.3100), genotoxicity 
(OPPTS 870.5100; 870.5300; 870.5375), teratogenicity (OPPTS 870.3700) 
and immunotoxicity (OPPTS 880.3550) for the active ingredient. 
Potassium silicate waiver requests were submitted (MRID 46434701). As 
mentioned above, the Agency has determined that the data requirements 
were met by the submission of public literature. The public literature 
demonstrates that potassium silicate has low toxicity by the oral route 
when tested as the TGAI because potassium silicate is neutralized by 
stomach acid and primarily excreted in the urine. The high pH of the 
pesticide product may cause eye and skin irritation to humans. However, 
risks to humans will be reduced by dilution of the pesticide product 
and further mitigated by the use of protective personal equipment.

IV. Aggregate Exposures

    In examining aggregate exposure, section 408 of FFDCA directs EPA 
to consider available information concerning exposures from the 
pesticide residue in food and all other non-occupational exposures, 
including drinking water from ground water or surface water and 
exposure through pesticide use in gardens, lawns, or buildings 
(residential and other indoor uses).

A. Dietary Exposure

    1. Food. Potassium is found in the environment and is present in 
the cells of humans and plants and is therefore an essential element in 
human and plant nutrition. It is found in many fruits and vegetables 
consumed by humans. Humans require an adequate supply of potassium from 
consumption of foods for healthy growth and development. Humans consume 
daily many sources of potassium, including a variety of fruits, 
vegetables and beverages such as barley, bananas, plums, apricots, 
strawberries, oranges, apples, grapes, spinach, potatoes, carrots, 
celery, tomatoes, lettuce, cucumbers, milk, fruit juices, coffee, white 
wine and light beers, etc. The average potassium content of the above 
fruits and vegetables ranges from 2.4 K/kg (tomato) - 3.7 K/kg 
(banana).
    As mentioned above, potassium is a common soil plant nutrient and 
fertilizer (as K2O), and comprises approximately 2.59% of 
the Earth's crust by weight. Silicon is a ubiquitous mineral nutrient 
in the environment (soil, water) and the second most abundant element 
in the lithosphere after oxygen. A nutritional trace element, silicon 
is required for proper and strong growth and development of mammalian 
bones. In plants, silicic acid (Si(OH)4) is rapidly 
absorbed. Once absorbed, silicic acid is readily circulated throughout 
the plant and deposited as silicon dioxide. Consequently exposure to 
soluble silica occurs on a daily basis and is a property of all plant 
products in the human diet. The concentration of silicon in vegetable 
plants varies greatly with cereals and grasses containing the highest 
concentrations (0.2-2.0%).
    Good agricultural practice when using potassium silicate means it 
will most likely be used in aqueous solutions because application of 
pure potassium silicate to crops is likely to be corrosive to crops 
since the active ingredient is a known corrosive. When applied to food 
crops at concentrations not to exceed 1% by weight of potassium 
silicate in aqueous solution, it is highly unlikely there will be any 
residues of significance in or on food.
    Further dilution by tank mixing with water of a pesticide product 
containing the active ingredient at 29% w/w of potassium silicate 
before application of the pesticide reduces the amount of active 
ingredient (to concentrations not to exceed 1% active ingredient) that 
will be on the crop.
    Furthermore, potassium silicate breaks down in the presence of 
water to potassium and silicate ions, both of which occur naturally in 
animals and plants. Concentrations of potassium silicate as a pesticide 
in foliar sprays and nutrient solutions are dominated by silicic acid, 
which as mentioned above, is readily absorbed by plants.
    Therefore, given the use dilution of the pesticide product and 
other good agricultural practices as required on product labels, the 
likely dietary exposures to potassium silicate from the pesticidal uses 
are not expected to add significantly to those levels of potassium 
silicate already found in foods, beverages, and in drinking water as a 
result of conventional agriculture and its natural occurrence in the 
environment.
    2. Drinking water exposure. Because potassium silicate breaks down 
into potassium and silicate ions in the presence of water, there will 
be no residues of potassium silicate in drinking water from its use as 
a pesticide. The Agency does not expect the resulting potassium and 
silicate ions resulting from this breakdown process will add 
significantly to the level of potassium and silica presently in the 
water.
    Potassium and silicon dioxide are ubiquitous in the environment, 
and the uses of soluble silicates are widespread in dishwashing soaps, 
other soaps, and detergents. Potassium silicate is classified by the 
FDA as a GRAS substance (21 CFR 182.90 and 21 CFR 182.1711) for limited 
use in canned potable water as a corrosion inhibiting agent. Moreover, 
both potassium and silicon are already present in natural waters. The 
potassium (natural) content of drinking water varies greatly depending 
on its source and may be larger in mineral and spa waters than ordinary 
tap water. On average, the daily water consumption by adults supplies 
less than 0.1% of their potassium intake (European Fertilizer 
Manufacturers Association, 1997). In natural waters most dissolved 
silica results from weathering of silicate minerals and it has been 
demonstrated that commercial soluble silicates rapidly degrade to 
molecular forms that are indistinguishable from natural dissolved 
silica. Therefore, because of the levels at which potassium and silica 
(silicon dioxide) are already present in the water supply, the Agency 
does not expect that the use of potassium silicate as a pesticide will 
result in detectable exposures aside from what is currently in the 
environment.

B. Other Non-Occupational Exposure

    1. Dermal exposure. Non-occupational dermal exposures to potassium 
silicate when used as a pesticide are expected to be negligible because 
it is limited to agricultural use.
    2. Inhalation exposure. Non-occupational inhalation exposures to

[[Page 34271]]

potassium silicate when used as a pesticide are expected to be 
negligible because it is limited to agricultural use and will be used 
as a spray.

V. Cumulative Effects

    Section 408(b)(2)(D)(v) of FFDCA requires that, when considering 
whether to establish, modify, or revoke a tolerance, the Agency 
considers available information concerning the cumulative effects of a 
particular pesticide's residues and other substances that have a common 
mechanism of toxicity.
    The information available at this time indicates that potassium 
silicate when applied to food crops at a rate less than or equal to 1% 
of potassium silicate by weight in aqueous solution does not have a 
toxic effect. Therefore, cumulative effects from the residues of this 
product are not anticipated.

VI. Determination of Safety for U.S. Population, Infants and Children

    1. U.S. population. The Agency has determined that there is 
reasonable certainty that no harm will result to the U.S. population 
from aggregated exposure to residues of potassium silicate when used in 
an aqueous solution in which the potassium silicate does not exceed 
29.1% by weight. This includes all anticipated dietary exposures and 
other exposures for which there is reliable information. The Agency 
arrived at this conclusion based on the anticipated low acute exposure 
estimates from its pesticidal use, the low mammalian toxicity in its 
diluted form, the widespread exposure to potassium and silica, from 
foods in the human diet, and the similarity both chemically and 
toxicologically to silicon dioxide which has already been fully 
characterized and assessed, and found that there is reasonable 
certainty of no harm that will result from the use of silicon dioxide 
and its related soluble silicates (potassium silicate) as an 
agricultural pesticide.
    2. Infants and children. FFDCA section 408 provides that EPA shall 
apply an additional tenfold margin of exposure (MOE) for infants and 
children in the case of threshold effects. Margins of exposure are 
often referred to as uncertainty or safety factors, and are used to 
account for potential prenatal and postnatal toxicity and any lack of 
completeness of the data base. Based on available data and other 
information, EPA may determine that a different MOE will define a level 
of concern for infants and children or that a MOE approach is not 
appropriate. Based on all the available information the Agency reviewed 
on potassium silicate, including a lack of threshold effects, the 
Agency concluded that potassium silicate, in its diluted form, is 
practically non-toxic to mammals, including infants and children. Since 
there are no effects of concern, the provision requiring an additional 
margin of safety does not apply.

VII. Other Considerations

A. Endocrine Disruptors

    Based on available data, no endocrine system-related effects have 
been identified with consumption of potassium silicate. In addition, 
there is no evidence to suggest that potassium silicate functions in a 
manner similar to any known hormone.

B. Analytical Method(s)

    The Agency proposes to establish an amendment to the exemption from 
the requirement of a tolerance without any numerical limitation for 
residues since it has determined that residues resulting from the 
pesticidal uses of potassium silicate would be so low as to be 
indistinguishable from the naturally occurring silicates that are 
ubiquitous in the environment.

C. Codex Maximum Residue Level

    There are no Codex Maximum Residue Levels for this chemical.

VIII. Conclusions

    Based on the toxicology data submitted, there is reasonable 
certainty no harm will result to the U.S. population including infants 
and children from aggregate exposure of residues of potassium silicate 
when the product is used in accordance with good agricultural 
practices. This includes all anticipated dietary exposures and all 
other exposures about which there is reliable information. As a result, 
EPA establishes an exemption from tolerance requirements pursuant to 
FFDCA 408(c) and (d) for residues of potassium silicate in or on all 
food commodities so long as the potassium silicate is not applied to 
food crops at rates that exceed 1% potassium silicate by weight in an 
aqueous solution.

IX. Statutory and Executive Order Reviews

    This final rule establishes an exemption from the tolerance 
requirement under section 408(d) of FFDCA in response to a petition 
submitted to the Agency. The Office of Management and Budget (OMB) has 
exempted these types of actions from review under Executive Order 
12866, entitled Regulatory Planning and Review (58 FR 51735, October 4, 
1993). Because this rule has been exempted from review under Executive 
Order 12866 due to its lack of significance, this rule is not subject 
to Executive Order 13211, Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use (66 FR 28355, 
May 22, 2001). This final rule does not contain any information 
collections subject to OMB approval under the Paperwork Reduction Act 
(PRA), 44 U.S.C. 3501 et seq., or impose any enforceable duty or 
contain any unfunded mandate as described underTitle II of the Unfunded 
Mandates Reform Act of 1995 (UMRA) (Public Law 104-4). Nor does it 
require any special considerations under Executive Order 12898, 
entitled Federal Actions to Address Environmental Justice in Minority 
Populations and Low-Income Populations (59 FR 7629, February 16, 1994); 
or OMB review or any Agency action under Executive Order 13045, 
entitled Protection of Children from Environmental Health Risks and 
Safety Risks (62 FR 19885, April 23, 1997). This action does not 
involve any technical standards that would require Agency consideration 
of voluntary consensus standards pursuant to section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (NTTAA), 
Public Law 104-113, section 12(d) (15 U.S.C. 272 note). Since 
tolerances and exemptions that are established on the basis of a 
petition under section 408(d) of FFDCA, such as the exemption in this 
final rule, do not require the issuance of a proposed rule, the 
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et 
seq.) do not apply. The Agency hereby certifies that this rule will not 
have significant negative economic impact on a substantial number of 
small entities. In addition, the Agency has determined that this action 
will not have a substantial direct effect on 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, as specified in Executive Order 13132, entitled Federalism 
(64 FR 43255, August 10, 1999). Executive Order 13132 requires EPA to 
develop an accountable process to ensure ``meaningful and timely input 
by State and local officials in the development of regulatory policies 
that have federalism implications.'' ``Policies that have federalism 
implications'' is defined in the Executive order to include regulations 
that have ``substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and

[[Page 34272]]

responsibilities among the various levels of government.'' This final 
rule directly regulates growers, food processors, food handlers and 
food retailers, not States. This action does not alter the 
relationships or distribution of power and responsibilities established 
by Congress in the preemption provisions of section 408(n)(4) of FFDCA. 
For these same reasons, the Agency has determined that this rule does 
not have any ``tribal implications'' as described in Executive Order 
13175, entitled Consultation and Coordination with Indian Tribal 
Governments (65 FR 67249, November 6, 2000). Executive Order 13175, 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' Policies that have tribal 
implications'' is defined in the Executive order to include regulations 
that have ``substantial direct effects on one or more Indian tribes, 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.'' This rule will not have 
substantial direct effects on tribal governments, on the relationship 
between the Federal Government and Indian tribes, or on the 
distribution of power and responsibilities between the Federal 
Government and Indian tribes, as specified in Executive Order 13175. 
Thus, Executive Order 13175 does not apply to this rule.

X. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of this final rule in the Federal Register. This final 
rule 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: May 31, 2006.
James Jones,
Director, Office of Pesticide Programs.

0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--AMENDED

0
1. The authority citation for part 180 continues to read as follows:

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

0
2. Section 180.1268 is added to subpart D to read as follows:

Sec.  180.1268  Potassium silicate; exemption from the requirement of a 
tolerance.

    Potassium silicate is exempt from the requirement of a tolerance in 
or on all food commodities so long as the potassium silicate is not 
applied at rates exceeding 1% by weight in aqueous solution and when 
used in accordance with good agricultural practices.
[FR Doc. E6-8939 Filed 6-13-06; 8:45 am]

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