Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

1 

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

MEMORANDUM

DATE: October 3, 2012

SUBJECT: Science Review in Support of PCC 38-DD, Containing 100% Powdered Corn Cobs (37% 

Cellulose) As Its Active Ingredient. 

Decision Number: 447146

DP Number: 402045

EPA File Symbol Number: 84889-R

Chemical Class: Biochemical

PC Code: 100154

CAS Number: 9004-34-6 (cellulose)

Active Ingredient Tolerance Exemptions: Nonfood-use

MRID Numbers: 48433401-48433405, 48433507-48433516, 

48534101-48534110, 48924801*there is no DP Number for 

these MRIDs.

FROM: Angela L. Gonzales, Biologist

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P)

TO: Leonard Cole, Senior Regulatory Specialist

Biochemical Pesticides Branch

Biopesticides & Pollution Prevention Division (7511P) 

ACTION REQUESTED

On behalf of Rode-Trol, LLC, E

x

ponent, Inc. requests registration of PCC 38-DD, a manufacturing-use product 

(MP) containing powdered corn cobs (37% cellulose). The chemical is a new biochemical active ingredient. 

The proposed MP is intended for use in the formulation of end-use products (EPs) that will be used as 

rodenticides in commercial and residential indoor settings. This product is related to the proposed end-use 

product, Rode-Trol (EPA File Symbol No.: 84889-E). In support of the proposed MP, the registrant submitted a 

proposed product label, Confidential Statement of Formulas (CSFs) dated 7/12/11, product chemistry data and 

information in MRIDs 48433401-48433402, 48534109, and 48924801 mammalian toxicology data and 

information in MRIDs 48433403, 48433405 and 48534101-48534108, and nontarget organism toxicology data 

and information in MRIDs 48433404 and 48534110. Companion animal/nontarget organism studies were 
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

2 

provided in MRIDs 48433507-48433516. Additional information was submitted in cover letter and attachments 

dated 5/11/12. 

RECOMMENDATIONS AND CONCLUSIONS

1. The product chemistry submission is ACCEPTABLE pending resolution of the deficiencies discussed 

below.

MRID 48433401-UPGRADEABLE MRID 48433402-UPGRADEABLE

MRID 48534109-UPGRADEABLE MRID 48924801-ACCEPTABLE

a. Refer to the Confidential Appendix (CA) below.

b. The active ingredient statement must be revised on the label as follows:

ACTIVE INGREDIENT:

Powdered Corn Cobs*...............................100%

*Contains 37% w/w Cellulose 

c. Refer to the CA below.

d. The applicant must rectify the discrepancy regarding the flash point data provided in MRID 48433402 and 

the data provided in box 9., “Flash Point/Flame Extension” on the CSF.

e. The rationale provided to satisfy the storage stability (OCSPP 830.6317) and corrosion characteristics 

(OCSPP 830.6320) is inadequate. Additional scientifically-sound rationale supported by references must be 

submitted or studies must be conducted. 

2. The mammalian toxicology submission is ACCEPTABLE.

MRID 48433403-UNACCEPTABLE MRID 48433405-SUPPLEMENTAL

MRID 48433507-SUPPLEMENTAL MRID 48433508-SUPPLEMENTAL

MRID 48433509-SUPPLEMENTAL MRID 48433510-SUPPLEMENTAL

MRID 48433511-SUPPLEMENTAL MRID 48433512-SUPPLEMENTAL

MRID 48433513-SUPPLEMENTAL MRID 48433514-SUPPLEMENTAL

MRID 48433515-SUPPLEMENTAL MRID 48433516-SUPPLEMENTAL

MRID 48534101-ACCEPTABLE MRID 48534102-ACCEPTABLE

MRID 48534103-ACCEPTABLE MRID 48534104-ACCEPTABLE

MRID 48534105-ACCEPTABLE MRID 48534106-ACCEPTABLE

MRID 48534107-ACCEPTABLE MRID 48534108-ACCEPTABLE

3. The nontarget organism toxicology submission is ACCEPTABLE.

MRID 48433404-UNACCEPTABLE MRID 48534110-SUPPLEMENTAL

NOTE TO RAL:

1. In the “Ingredients” row on the data matrix dated 7/12/11, the applicant listed the active ingredient as monoand di- potassium salts of phosphorous acid, which must be revised.

2. Since the product may be applied in open trays, the applicant should include language on the label to 

preclude exposure to nontarget organisms/pets, such as cats and dogs. 

PRODUCT CHEMISTRY ASSESSMENT AND STUDY SUMMARIES
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

3

I. Active Ingredient Characterization 

Powdered corn cobs are shelled corn cobs that have been dried and ground. Cellulose, which is the actual 

pesticidal component in the cobs, comprises approximately 37% of the powdered corn cobs. The mode of action 

of cellulose as a rodenticide is posited to be interference with osmoregulation in the intestines of rats and mice 

which results in dehydration, malnutrition and consequently, death. A second theory regarding the mode of 

action of the active ingredient is that because cellulose is indigestible by non-ruminant mammals, consumption 

of excessive amounts of the material may result in intestinal dysfunction. 

Cellulose, a polysaccharide, is one of the most abundant organic compounds on Earth. It is the main constituent 

of plant cell walls and is also produced by some algae, fungi and bacteria. It is consumed in its natural state (as 

a component of plants) by humans and animals and is used in a variety of products, such as paper, textiles and 

building materials. (French, 2003) Various derivatives of cellulose, including powdered cellulose and 

microcrystalline cellulose are approved by the FDA for use in food and pharmaceutical products (21 CFR). 

Under the Federal Food, Drug and Cosmetic Act (FFDCA), EPA has exempted the compound from the 

requirement of a tolerance as a minimum risk active and/or inert ingredient in food-use pesticide products (40 

CFR 180.950(e)). The Agency has also approved cellulose as a nonfood-use inert ingredient in pesticide 

products. In 2007, cellulose from powdered corn cobs was approved for use as a rodenticide in Canada by the 

Pest Management Regulatory Agency (PMRA). 

A. Product Chemistry (MRIDs 48433401-48433402, 48534109 and 48924801)

All data requirements have been satisfied with the exception of storage stability and corrosion characteristics.

Data submitted to support the product chemistry data requirements are summarized in Table 1 below. Physical 

and chemical properties data are summarized in Table 2 below. Data Evaluation Records (DERs) were not 

created for MRIDs 48433401-48433402, 48534109 and 48924801. Refer to the CA below for more 

information.

TABLE 1. Product Chemistry Data Requirements for Powdered Corn Cobs (Cellulose) (40 CFR § 158.2030)

OSCPP Guideline No. Study Results MRID

830.1550

to

830.1670

Product identity;

Manufacturing process;

Discussion of formation of 

unintentional ingredients

Submitted data satisfy the requirements for 

product identity, manufacturing process, and 

discussion of formation of impurities

48433401

48534109

830.1700 Analysis of samples Submitted data satisfy the requirements for 

analysis of samples.

48924801

830.1750 Certification of limits Limits listed in the CSF are acceptable. 48433401

48534109

830.1800 Analytical method Acceptable. 48433401
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

4

TABLE 2. Physical and Chemical Properties of Powdered Corn Cobs (Cellulose) (40 CFR § 158.2030)

OCSPP Guideline Property Description of Result

(PC 38-DD) MRID

830.6302 Color Yellow-brown 48433402

830.6303 Physical State Solid 48433402

830.6304 Odor Faintly sweet 48433402

830.6313 Stability to Normal and Elevated

Temperatures, Metals and Metal 

Ions

Stable 48433402

830.6315 Flammability Flash point: 388oF (open cup); 396 oF (closed cup) 48433402

830.6317 Storage Stability Rationale is inadequate 48433402

830.6319 Miscibility N/A: product is not an emulsifiable liquid that will 

be diluted with petroleum solvents

48433402

830.6320 Corrosion Characteristics Rationale is inadequate 48433402

830.7000 pH N/A: TGAI/MP is not soluble or dispersible in water 48433402

830.7050 UV/Visible Light

Absorption

Data are not necessary to inform the risk assessment 48433402

830.7100 Viscosity N/A: product is a solid 48433402

830.7200 Melting Point/Range Not expected to melt 48433402

830.7220 Boiling Point/Range N/A: TGAI is a solid 48433402

830.7300 Bulk Density 28.0 lb/ft348433402

830.7520 Particle Size, Fiber Length and 

Diameter Distribution

Coarse dust index: 0.89

Coarse dust: 9.78 X 10-5 %

Crude fiber: 36.9%

48433402

830.7550

830.7560

830.7570

Partition Coefficient (nOctanol/Water)Data are not necessary to inform the risk assessment 48433402

830.7840 Water Solubility 6.3% in water 48433402

830.7950 Vapor Pressure N/A: TGAI/MP is a solid 48433402

II. Human Health Assessment

A. Toxicology (MRIDs 48433403, 48433405, 48534101-48534108 and 48433507-48433516)

To satisfy the toxicology data requirements, data were provided from the open scientific literature. 

Reviews and analyses of these data by the World Health Organization (WHO) and PMRA were also submitted. 

For all data requirements (where applicable), adequate data on surrogate chemicals such as microcrystalline 

cellulose or refined-alpha cellulose were submitted. These chemicals are derivatives of cellulose. Instead of 

submitting data on the toxicity of powdered corn cobs, data were submitted on cellulose because the compound 

is considered to be the pesticidal component of the powdered corn cobs. The data submitted are acceptable to 

qualitatively assess the toxicity of the active ingredient.

All toxicology data requirements have been satisfied per 40 CFR 158.2050. The data presented in Table 3

below are a summary of the toxicity data for powdered corn cobs (cellulose). DERs were not created for the 

submitted MRIDs; however, the relevant data and information from these MRIDs are summarized in Table 3 

and in the subsequent sections.
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

5

Table 3. Mammalian Toxicology Data for Powdered Corn Cobs (Cellulose) (40 CFR § 158.2050)

Study/OCSPP Guideline No. Results Toxicity 

Category/Description MRID

Acute oral toxicity (rat)

(870.1100)

LD50 > 3160 mg/kg1,3 (males)

LD50 > 5000 mg/kg2,3 (females and males) IV 4843340548534101

Acute dermal toxicity (rat)

(870.1200) LD50 > 2000 mg/kg2,3 (females and males) III 4843340548534102

Acute inhalation toxicity (rat)

(870.1300) LC50 > 5.35 mg/L2,3 (females and males) IV 4843340548534103

Primary eye irritation (rabbit)

(870.2400) Minimally irritating2

IV

48433405

48534104

Primary dermal irritation (rabbit)

(870.2500) Nonirritating2

IV 48433405

Dermal sensitization (guinea pig)

(870.2600) Not a sensitizer2 N/A 4843340548534105

90-Day oral toxicity 

(870.3100)

The proposed EP is nonfood-use. Uses are not 

anticipated to result in repeat oral exposure to 

humans.

Based on the review of available toxicity studies, the 

World Health Organization (WHO) has concluded

that there is no evidence to indicate that consumption 

of microcrystalline cellulose in foods (when foods are 

produced according to good manufacturing 

processes) will result in toxic effects in humans.

Humans are already naturally exposed to cellulose 

through consumption of plants and other foods.

48433405

48534106

90-Day dermal toxicity

(870.3250)

Purposeful application and prolonged exposure to the 

human skin is not anticipated based on the use pattern 

(the proposed EP will be placed in bait stations or in 

trays and left alone to attract rodents). Additionally, 

humans are already exposed to cellulose and cellulose 

derivatives in paper products, textiles,

pharmaceuticals, foods and plants.

90-Day inhalation toxicity

(870.3465)

Significant repeat inhalation exposure to the active 

ingredient as a gas, vapor or aerosol is unlikely based 

on the physical properties of the active ingredient. 

Powdered corn cobs (cellulose) are a solid material 

and the proposed EP is formulated as a pellet which is

not inhalable. Although dust may be generated during 

the life-cycle of the product, significant exposure is 

not anticipated and the active ingredient is of low 

inhalation toxicity. The use pattern also precludes 

exposure (the proposed EP will be placed in bait 

stations or in trays and left alone to attract rodents).

Mutagenicity-in vitro studies

(870.5100)

Significant human exposure is unlikely based on use 

pattern (the proposed EP will be placed in bait 

stations or in trays and left alone to attract rodents). 

The proposed EP is for nonfood-uses only.

Various mutagenicity assays with microcrystalline 

cellulose in Salmonella typhimurium and Escherichia 

coli were reviewed by the WHO. All results were 

negative for genotoxicity.

48433405

48534108
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

6

Table 3. Mammalian Toxicology Data for Powdered Corn Cobs (Cellulose) (40 CFR § 158.2050)

Study/OCSPP Guideline No. Results Toxicity 

Category/Description MRID

Mutagenicity-in vivo micronucleus assay 

(870.5395)

Significant human exposure is unlikely based on use 

pattern (the proposed EP will be placed in bait 

stations or in trays and left alone to attract rodents). 

The proposed EP is for nonfood-uses only.

In vivo mouse erythrocyte micronucleus mutagenicity 

assays using microcrystalline cellulose were reviewed 

by the WHO. All results were negative for 

genotoxicity.

48433405

48534108

Developmental toxicity

(870.3700)

Significant female human exposure is unlikely based 

on use pattern (the proposed EP will be placed in bait 

stations or in trays and left alone to attract rodents). 

The proposed EP is for nonfood-uses only.

No developmental toxicity effects were observed in 

studies with microcrystalline cellulose reviewed by 

the WHO. 

48433405

48534107

1Test substance was refined alpha-cellulose.

2Test substance was 85% microcrystalline cellulose.

3Highest dose tested.

1. Acute Toxicity

All data submitted to support the acute toxicology data requirements were submitted from the open scientific 

literature and were obtained from studies conducted on acceptable surrogate chemicals for cellulose, such as 

microcrystalline cellulose. Microcrystalline cellulose is purified, partially depolymerized cellulose (MRID 

48433405, p. 95 of 110). Based on the available data and information, the Agency has classified cellulose as 

having low acute oral, acute dermal and acute inhalation toxicity. It is minimally irritating to the eye, is not a 

dermal irritant and is not a dermal sensitizer. 

All of the acute toxicity data referenced above were also reviewed by the World Health Organization (WHO)

and Canada’s Pest Management Regulatory Agency (PMRA) and found to be acceptable.

2. Subchronic Toxicity

90-Day Oral

The 90-day oral data requirement is conditionally required for nonfood uses that are likely to result in repeat 

oral exposure to humans. The proposed product is intended for use to formulate end-use products (EPs) which 

will be used as rodenticides in indoor settings. Repeat human oral exposure is not expected based on the 

proposed use pattern of the product containing the active ingredient. The proposed product containing the active 

ingredient is for nonfood-use and the product will be placed in bait stations and/or trays and left alone to attract 

rodents. Label instructions will include precautionary statements to mitigate exposure to applicators and

children. Any oral exposure is likely to be accidental; repeated oral exposure is not anticipated. In the case that 

accidental exposure should occur, hazard data indicate that ingestion of cellulose is not likely to result in toxic 

effects. Several subchronic and chronic oral toxicity studies were cited (actual studies were not provided) in 

MRID 48534106 for derivatives of cellulose. Most of the studies were conducted using microcrystalline 

cellulose. In their safety evaluation of microcrystalline cellulose, the WHO reviewed these studies and 
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

7

concluded that there is no evidence to indicate that consumption of microcrystalline cellulose in foods (when 

foods are produced according to good manufacturing processes) will result in toxic effects in humans (MRID 

48433405, p. 25 of 100). Moreover, humans are already naturally exposed via the oral route to cellulose through 

consumption of plants and other foods.

90-Day Dermal

The 90-day dermal data requirement is conditionally required to support uses involving purposeful application 

to the human skin or uses that would result in prolonged dermal exposure and if data from a 90-day oral study

are not required or the active ingredient is known or expected to be metabolized differently by the dermal route 

of exposure than by the oral route and the metabolite is of toxicological concern. Purposeful application and 

prolonged exposure to the human skin is not anticipated based on the use pattern of the proposed product (the 

product will be placed in bait stations and/or trays and left alone to attract rodents). Label instructions will 

include precautionary statements to mitigate exposure to children. Additionally, humans are already exposed via 

the dermal route to cellulose in paper products, textiles, foods and plants.

90-Day Inhalation

The 90-day inhalation data requirement is conditionally required if there is a likelihood of significant levels of 

repeated inhalation exposure to the pesticide as a gas, vapor or aerosol. For the proposed uses of powdered corn 

cobs (cellulose) as a pesticide, repeated inhalation exposure is unlikely based on the physical properties of the 

active ingredient, which is a solid. The proposed EP is formulated as a pellet which is not inhalable. Although 

dust may be generated from the product containing the active ingredient during shipping and/or handling, 

significant exposure is not anticipated and the active ingredient is of low inhalation toxicity. The use pattern 

also precludes exposure (the proposed EP will be placed in bait stations or in trays and left alone to attract 

rodents). 

3. Developmental Toxicity

Developmental toxicity data are conditionally required if significant exposure to female humans is expected 

from the proposed product’s use under widespread and commonly recognized practice. Significant exposure to 

females is unlikely based on the proposed use pattern of the product containing the active ingredient (the 

product will be placed in bait stations and/or trays and left alone to attract rodents). If used according to label 

instructions, significant oral, dermal and inhalation exposure to the active ingredient is not anticipated.

Moreover, no developmental toxicity effects were observed in studies with microcrystalline cellulose reviewed 

by the WHO (MRID 48433405, p. 21 of 110). 

4. Mutagenicity

Mutagenicity data are conditionally required to support nonfood uses if the use is likely to result in significant 

human exposure or if the active ingredient or its metabolites are structurally related to a known mutagen or 

belong to any chemical class of compounds containing a known mutagen. Significant human exposure is 

unlikely based on the use pattern (the proposed EP will be placed in bait stations or in trays and left alone to 

attract rodents). Additionally, the proposed EP is for nonfood-uses only. Moreover, in studies reviewed by the 

WHO, microcrystalline cellulose was not mutagenic in various in vitro mutagenicity assays in Salmonella 
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

8

typhimurium and Escherichia coli and it was not mutagenic in in vivo mouse erythrocyte micronucleus 

mutagenicity assays. 

5. Companion Animal/Nontarget Animal Toxicity and Risk Characterization

In order to assess the potential for hazardous effects to various species, including pets, which may encounter the 

product containing the active ingredient during use, several non-guideline toxicity studies were conducted and 

submitted to the Agency (MRIDs 48433507-48433516). The species tested were: brushtail possum 

(Trichosurus vulpecula), rabbit (Oryctolagus cuniculus cuniculus), guinea pig (Cavia porcellus), cat (Felis 

catus), dog (Canis familiaris), ferret (Mustela furo), chicken (Gallus gallus), duck (Anas platyrhynchos) and 

goldfish (Carassius auratus). In each study, test species were deprived of their normal diet for 24 hours and 

then presented with the product containing the active ingredient and a half-ration of their normal food. The 

feeding schedule continued for up to 10 days. Animals were observed for daily consumption and changes in 

body weight and behavior. Animals that consumed at least 5g test substance/kg body weight were euthanized 

and examined for gross pathological effects. Possums, cats, chickens, dogs and ferrets typically refused the 

product after sampling small to moderate quantities. Guinea pigs, rabbits and male ducks consumed appreciable 

amounts of the product over the testing period. No changes in behavior were observed in any of these species 

during the test period. Gross pathology observations were normal for these species with the exception of 

observations of possible reduced urine production in possums, guinea pigs and rabbits and dry feces in some 

ducks. Goldfish mortality occurred between the first day and 19 days post-application (the product was applied 

to simulate an accidental spillage into a fish tank or pond). It was not determined if mortality occurred due to 

water contamination from the product or from consumption of the product. 

Based on the data provided, the product appears to be unpalatable to possums, cats, chickens, dogs and ferrets. 

Should accidental consumption occur, the available data indicate that accidental exposure should not result in 

toxic effects to these species. Although guinea pigs, rabbits and ducks may consume the product, the available 

data indicate that accidental exposure should not result in toxic effects. Accidental exposure to fish may result 

in mortality based on the data submitted; however, exposure is not expected based on the use pattern of the 

product. Risk to all of the above species is expected to be negligible based on minimal toxicity and lack of 

exposure if label instructions are followed. 

B. Dose Response Assessment

No relevant toxicological endpoints were identified; therefore, a dose response assessment is not required.

C. Drinking Water Exposure and Risk Characterization

Based on the proposed use pattern of powdered corn cobs (cellulose) as a rodenticide, pesticide residues in 

drinking water are not expected when products are used according to label instructions. Products containing the 

active ingredient will be used in indoor commercial and residential settings only; therefore, cellulose residues in 

drinking water are highly unlikely. 
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

9

D. Occupational, Residential, School and Day Care Exposure and Risk Characterization

1. Occupational Exposure and Risk Characterization

An occupational exposure assessment was not conducted for powdered corn cobs (cellulose). Based on the

proposed use pattern and toxicity data available to the Agency, anticipated exposure is not likely to result in 

unreasonable risk to applicators/handlers. Any occupational exposure is likely to be via the dermal route and is 

expected to be brief in duration. Any inhalation exposure to dust generated during the life-cycle of the product 

is not expected to be significant and is also expected to be brief in duration. The active ingredient is of low 

dermal and inhalation toxicity. No relevant toxicological endpoints were identified and significant exposure in 

an occupational setting is not expected if label instructions are followed. Additionally, humans are already

exposed to cellulose in the diet and through use of various products such as paper and textiles.

2. Residential, School and Day Care Exposure and Risk Characterization

A residential, school and day care exposure assessment was not conducted for powdered corn cobs (cellulose). 

Based on the proposed use pattern and toxicity data available to the Agency, anticipated exposure is not likely

to result in unreasonable risk to humans. No relevant toxicological endpoints were identified and significant 

exposure is not expected if label instructions are followed. Any exposure in residential, school and/or day care 

settings is likely to be accidental and data available to the Agency indicate that the active ingredient is of low 

toxicity. Additionally, humans are already exposed to cellulose in the diet and through use of various products 

such as paper and textiles. 

E. Risk Characterization

Risk to humans from pesticidal use of powdered corn cobs (cellulose) is expected to be negligible due to the 

low toxicity of the active ingredient and the anticipated lack of exposure based on the use pattern. The proposed 

product is not used in or on food, and is not directly applied to humans. Appropriate precautionary language 

requirements on end-use product labels will further mitigate exposure. 

The Agency has considered powdered corn cobs (cellulose) in light of the relevant safety factors in FIFRA. A 

determination has been made that no unreasonable adverse effects to the U. S. population in general, and to 

infants and children in particular, will result from the use of this chemical when label instructions are followed.

III. Environmental Assessment

A. Nontarget Organism Toxicology (MRIDs 48433404, 48433510-48433512 and 48534110)

All nontarget toxicology data requirements have been satisfied per 40 CFR 158.2060. The information 

presented in Table 4 below is a summary of the nontarget toxicology data and information for powdered corn 

cobs (cellulose). DERs were not created for the submitted MRIDs; however, data and information from these 

MRIDs are summarized in Table 4 and in the subsequent sections. 

TABLE 4. Nontarget Organism Toxicity Requirements for Powdered Corn Cobs (Cellulose) (40 CFR § 158.2060)
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

10

Study/OCSPP Guideline No.

/MRID No.

Results Toxicity 

Category/Description

MRID

Avian acute oral toxicity

Colinus virginianus

(850.2100)

Waived. Avian exposure is not anticipated 

based on the indoor-use pattern.

Non-guideline toxicity studies were 

submitted where Mallard ducks and chickens 

were exposed to the proposed EP in the diet. 

Mallard ducks consumed the product over 3-

10 days; there were no signs of toxicity and 

gross pathology was normal. The feces of 

some birds were dry and crumbly on day 6 

(avian feces are normally wet). Chickens 

consumed low to moderate amounts of the 

product for about 2 days; thereafter, 

consumption was negligible. There were no 

signs of toxicity and gross pathology was 

normal. Feces were normal as well. 

Practically nontoxic 48433511

48433512

Avian dietary toxicity

Colinus virginianus and Anas 

platyrhynchos (850.2200)

Waived. Avian dietary exposure is not 

anticipated based on indoor-use pattern. N/A

Aquatic invertebrate acute toxicity

(Daphnia magna)

(850.1010)

Waived. Aquatic invertebrate exposure is not 

anticipated based on indoor-use pattern. 

There is no direct application to aquatic sites 

and runoff is not expected based on use 

limitations to indoor settings.

N/A

Freshwater fish LC50

(Oncorhynchus mykiss)

(850.1075)

Waived. Aquatic vertebrate exposure is not 

anticipated based on indoor-use pattern. 

There is no direct application to aquatic sites 

and runoff is not expected based on use 

limitations to indoor settings.

The proposed end-use product was highly 

toxic to goldfish based on a non-guideline 

toxicity study conducted where goldfish were 

exposed to the product in a simulation of 

accidental spillage into a fish tank or pond. It 

was not determined if toxicity was due to 

water contamination from the product or 

from consumption of the product. Although 

the product may be toxic to aquatic 

vertebrates, exposure to these organisms is 

highly unlikely if label instructions are 

followed.

N/A 48433510

Nontarget plant studies-seedling 

emergence

(850.4100)

Data are not required for indoor uses. N/A

Nontarget plant studies-vegetative 

vigor 

(850.4150)

Data are not required for indoor uses. N/A

Nontarget insect testing (Apis 

mellifera)

(880.4350)

Data are not required for indoor uses. N/A
Powdered Corn Cobs (Cellulose) DP Number: 402045

PC Code: 100154 EPA File Symbol No.: 84889-R

Type of Review: Product Chemistry, Toxicology, Nontargets

11

1. Toxicity Summaries

Non-guideline toxicity studies were submitted for birds and non-rodent mammals (refer to the Companion 

Animal/Nontarget Animal Toxicity and Risk Characterization section above for a summary of submitted data). 

The indoor-use pattern precludes exposure for nontarget species. The proposed product containing the active 

ingredient will be placed in bait stations or bait trays indoors and left alone to attract rodents. Based on the 

submitted data and information, the active ingredient is not toxic to birds and mammals. The avian acute oral, 

avian dietary, aquatic vertebrate, aquatic invertebrate, nontarget plant and nontarget insect toxicity studies were 

waived due to the lack of anticipated exposure based on the indoor-only use pattern. 

B. Environmental Fate and Groundwater Data

Environmental fate and groundwater data are not required at this time because the results of the nontarget 

organism toxicity assessment (Tier I data requirements) did not trigger these Tier II data requirements. 

C. Ecological Exposure and Risk Characterization

A risk assessment was not conducted for nontarget organisms due to the unlikelihood of exposure based on the 

indoor-only use pattern of the active ingredient. Unreasonable effects to nontarget organisms are not anticipated 

when products are used according to label instructions. 

D. Endangered Species Assessment

The Agency has not conducted a risk assessment that supports a complete endangered species determination. 

The ecological risk assessment planned during registration review will allow the Agency to determine whether 

powdered corn cobs’ (cellulose) use has “no effect” or “may effect” federally listed threatened or endangered 

species (listed species) or their designated critical habitats. When an assessment concludes that a pesticide’s 

use “may affect” a listed species or its designated critical habitat, the Agency will consult with the U.S. Fish and 

Wildlife Service and/or National Marine Fisheries Services (the Services) as appropriate. 

REFERENCES

French, A. D., Bertoniere, N. R., Brown, R. M., Chanzy, H., Gray, D., Hattori, K. and Glasser, W. 2003. 

Cellulose. Kirk-Othmer Encyclopedia of Chemical Technology. Published Online: October 17, 2003