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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

 OFFICE OF CHEMICAL SAFETY 

 AND POLLUTION PREVENTION 

 

MEMORANDUM

Date: 9/2/10 

SUBJECT: Cyflufenamid: Human Health Risk Assessment for Proposed Uses on Cucurbit 

Vegetables (Crop Group 9), Pome Fruit (Crop Group 11), Small Fruit Vine Climbing Except 

Fuzzy Kiwifruit (Subgroup 13-07F), and Low Growing Berry (Subgroup 13-07G), except 

Cranberry. 

 

PC Code: 555550 DP Barcode: : D360825

Decision No.: 403833 Registration No.: 8033-RNG

Petition No.: 8F7488 Regulatory Action: Section 3 Registration

Risk Assessment Type: Single 

Chemical/Aggregate

Case No.: NA 

TXR No.: NA CAS No.: 180409-60-3

MRID No.: NA 40 CFR: 180.xxx (pending)

FROM: Nancy Dodd, Risk Assessor 

 Risk Assessment Branch III (RAB3) 

 Health Effects Division (HED) (7509P) 

 AND 

 Sheila Healy, Ph.D., Toxicologist 

Meheret Negussie, Chemist 

 Cassi L.Walls, Ph.D., Senior Biologist 

 RAB3/HED (7509P) 

THROUGH: Paula Deschamp, Branch Chief 

 RAB3/HED (7509P) 

 AND 

 Christina Swartz, Branch Chief 

 PV Shah, Toxicologist 

 Risk Assessment Review Committee 

 

TO: Mark Suarez/Samantha Hulkower, Risk Management Team #11 

 Insecticide Branch 

 Registration Division (7505P) 
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Table of Contents 

1.0 Executive Summary .......................................................................................................... 4 

2.0 Regulatory Conclusions and Recommendations ............................................................ 7 

2.2.1 Enforcement Analytical Method ............................................................................. 9 

2.2.2 International Harmonization ................................................................................... 9 

2.2.3 Recommended Tolerances........................................................................................ 9 

2.2.4 Revisions to Petitioned-For Tolerances ................................................................ 10 

2.3 Label Recommendations ............................................................................................ 10 

2.3.1 Recommendations from Residue Reviews ............................................................ 10 

2.3.2 Recommendations for Worker Safety ................................................................... 10 

2.3.3 Recommendations for Residential Safety ............................................................. 11 

3.0 Ingredient Profile ............................................................................................................ 11 

3.1 Structure and Nomenclature ..................................................................................... 11 

3.2 Physical/Chemical Characteristics ............................................................................ 12 

3.3 Summary of Existing/Proposed Uses ........................................................................ 12 

4.0 Hazard Characterization and Dose-Response Assessment ......................................... 14 

4.1 Toxicology Studies Available for Analysis ................................................................ 14 

4.2 Absorption, Distribution, Metabolism, & Elimination (ADME) ............................ 15 

4.2.1 Dermal Absorption ................................................................................................. 16 

4.3 Toxicological Effects ................................................................................................... 17 

4.4 Safety factor for Infants and Children (FQPA Safety Factor) ............................... 18 

4.4.1 Completeness of the Toxicology Database ............................................................ 18 

4.4.2 Evidence of Neurotoxicity ...................................................................................... 19 

4.4.3 Evidence of Sensitivity/Susceptibility in the Developing or Young Animal ...... 20 

4.4.4 Residual Uncertainty in the Exposure Database.................................................. 20 

4.5 Toxicity Endpoint and Point of Departure Selections ............................................. 21 

4.5.1 Dose-Response Assessment .................................................................................... 21 

4.5.2 Recommendation for Combining Routes of Exposures for Risk Assessment ... 22 

4.5.3 Classification of Carcinogenic Potential ............................................................... 22 

4.5.4 Summary of Points of Departure and Toxicity Endpoints Used in Human Risk 

Assessment ............................................................................................................................... 22 

4.5.5 Endocrine Disruption ............................................................................................. 24 

5.0 Dietary Exposure and Risk Assessment ........................................................................ 25 

5.1 Metabolite/Degradate Residue Profile ...................................................................... 25 

5.1.1 Summary of Plant and Animal Metabolism Studies ........................................... 25 

5.1.2 Summary of Environmental Degradation ............................................................ 26 

5.1.3 Comparison of Metabolic Pathways ...................................................................... 27 

5.1.4 Residues of Concern Summary and Rationale ..................................................... 28 

5.2 Food Residue Profile ................................................................................................... 31 

5.3 Water Residue Profile................................................................................................. 33 

5.4 Dietary Risk Assessment ............................................................................................ 34 

5.4.1 Description of Residue Data Used in Dietary Assessment .................................. 34 

5.4.2 Percent Crop Treated Used in Dietary Assessment ............................................. 34 

5.4.3 Acute Dietary Risk Assessment ............................................................................. 34 
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5.4.4 Chronic Dietary Risk Assessment ......................................................................... 35 

5.4.5 Cancer Dietary Risk Assessment ........................................................................... 35 

5.4.6 Summary Table ....................................................................................................... 35 

6.0 Residential (Non-Occupational) Exposure/Risk Characterization ............................ 36 

6.1 Residential Handler Exposure ................................................................................... 36 

6.2 Post-Application Exposure ......................................................................................... 39 

6.3 Combined Exposure.................................................................................................... 39 

6.4 Spray Drift ................................................................................................................... 40 

7.0 Aggregate Exposure/Risk Characterization ................................................................. 40 

7.1 Acute Aggregate Risk ................................................................................................. 40 

7.2 Short- and Intermediate-Term Aggregate Risk ....................................................... 40 

7.3 Chronic Aggregate Risk ............................................................................................. 41 

7.4 Cancer Aggregate Risk ............................................................................................... 41 

8.0 Cumulative Exposure/Risk Characterization .............................................................. 42 

9.0 Occupational Exposure/Risk Characterization ........................................................... 42 

9.1 Short-/Intermediate-/Long-Term/Cancer Handler Risk......................................... 42 

9.2 Short-/Intermediate-/Long-Term/Cancer Post-Application Risk .......................... 47 

10.0 Incidents ........................................................................................................................... 49

11.0 Environmental Justice Considerations ......................................................................... 49 

12.0 References ........................................................................................................................ 50 

Appendix A. Toxicology Profile and Executive Summaries .................................................. 51 

A.1 Toxicology Data Requirements .................................................................................. 51 

A.2 Toxicity Profiles .......................................................................................................... 52 

A.3 Hazard Identification and Endpoint Selection ......................................................... 58 

A.4 Executive Summaries .................................................................................................. 59 

Appendix B. Metabolism Summary Table .............................................................................. 85 

Appendix C. Review of Human Research................................................................................ 92 

Appendix D. International Residue Limit Status Sheet ......................................................... 93 

Appendix E. Data Required as a Condition of Registration .................................................. 94 
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1.0 Executive Summary 

Use Profile: Nippon Soda Company, Ltd. has proposed uses for cyflufenamid on cucurbit 

vegetables (Crop Group 9), pome fruit (Crop Group 11), small fruit vine climbing except fuzzy 

kiwifruit (Subgroup 13-07F), low growing berry (Subgroup 13-07G), except cranberry, and 

outdoor landscape and outdoor nursery ornamentals. The petitioner voluntarily withdrew the use 

on cranberry. Cyflufenamid is a fungicide which controls powdery mildews. Its mode of action 

has not been determined. 

Cyflufenamid is formulated as suspension concentrates, and applied as postemergence broadcast 

foliar sprays using ground or aerial equipment. Application through any type of irrigation 

system is prohibited. A maximum of two applications can be made to agricultural crops and 

ornamentals for a maximum of 0.022 lb ai/A/growing season (cucurbits), 0.044 lb ai/A/growing 

season (other agricultural crops), and 0.044 lb ai/A/year (ornamentals). For agricultural crops (as 

shown in Table 3.3), retreatment intervals (RTIs) are 7 or 14 days and preharvest intervals 

(PHIs) are 0, 3, or 14 days. Retreatment intervals for ornamentals are 14-21 days. The restricted 

entry interval (REI) is 12 hours. 

 

These actions will be the first registrations in the U.S. Cyflufenamid is registered in Japan, 

Korea, and several European Union (EU) countries. 

Human Health Risk Assessment: 

Cyflufenamid has low acute toxicity via the oral, dermal and inhalation routes of exposure. 

Though slightly irritating to the eye, cyflufenamid is not a skin irritant or sensitizer. In the 

longer-term studies of the mammalian toxicology database, the liver was the primary target 

organ of cyflufenamid toxicity. Across species, duration and gender, changes in weight, clinical 

chemistry and pathology indicated treatment-related perturbations in and adverse effects on liver 

function. Treatment-related effects were also observed in the rat thyroid and kidney. 

Cyflufenamid-induced cardiotoxicity in the mouse and rat, myocardial vacuolation and lipidosis 

could be ascribed to the in vitro inhibition of carnitine palmitoyltransferase by cyflufenamid. 

An acute endpoint attributable to a single dose was not identified. The chronic NOAEL of 4.4 

mg/kg/day was based on decreased body weight gain, increased thyroid/parathyroid weight, 

increased liver weight and centrilobular hepatocytic hypertrophy in the combined chronic 

toxicity/carcinogenicity study in rats. No dermal hazard was identified. The incidental oral and 

inhalation NOAELs of 5 mg/kg/day are based on decreased body weight, body weight gain and 

food consumption in a prenatal developmental study in rabbits. 

Cyflufenamid is classified as “likely to be carcinogenic to humans.” This was based on the 

presence of two tumor types in two species: thyroid follicular cell tumors in male rats and liver 

tumors in male mice. There is no concern for mutagenicity. The unit risk, Q1

*

, of cyflufenamid 

based upon male mouse liver combined adenoma and carcinoma tumor rates is 6.61 x 10-3

(mg/kg/day)-1 in human equivalents. 
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Dietary Exposure (Food/Water): 

 

The residue chemistry data and environmental fate data are adequate to assess human exposure. 

The chronic and cancer dietary food exposure assessments are conservative. The assessments 

are based on reliable data and will not underestimate exposure/risk. 

Chronic: A partially refined chronic dietary assessment was conducted. The assumptions of this 

dietary assessment included average field trial residues for all proposed crops and 100% crop 

treated (CT). Empirical or DEEMTM default processing factors were used. The ground water 

estimated drinking water concentration (EDWC) of 4.68 ug/L was incorporated directly into the 

dietary assessment (DP# 362954, R. Bohaty, 5/3/2010). 

The non-cancer chronic dietary (food and drinking water) exposure to cyflufenamid is below 

HED’s level of concern [i.e., <100% of the chronic Population Adjusted Dose (cPAD)] for the 

general U.S. population and all population subgroups. The chronic dietary exposure estimates 

are <1% of the cPAD for the general U.S. population and 1% of the cPAD for all infants (<1 

year old), the most highly exposed population subgroup. 

 

Cancer: The cancer dietary (food and drinking water) exposure estimate for the general U.S. 

population is 9.5 x 10-7, which is below HED’s level of concern (generally in the range of 10-6). 

Residential Exposure: 

Residential Handler: Residential short-term (1 - 30 days) dermal and inhalation exposures are 

expected from handler activities associated with the proposed ornamental uses. Since no hazard 

was identified for the dermal route of exposure, dermal risks were not assessed. HED used data 

from ORETF and PHED Version 1.1 to assess residential handler exposures. Margins of 

Exposure (MOEs) greater than 100 for the inhalation route are deemed adequate to protect 

residential cyflufenamid handlers. All inhalation scenarios for residential handlers resulted in 

MOEs greater than the level of concern LOC (i.e., MOEs ≥ 100) and, therefore, are not of 

concern. All residential handler scenarios resulted in cancer risks which do not exceed HED’s 

level of concern (generally in the range of 10-6) when wearing baseline clothing (e.g., shortsleeve shirt, short pants, and no gloves). It should be noted that the proposed label states “Not 

for homeowner use”; however, HED assessed residential handler exposure activities for the 

ornamental uses because there is a potential that homeowners could apply this product. HED 

recommends that the label language be revised to clarify the specific type of applicator and 

setting (i.e., “applications made only by licensed pest control operators in commercial and 

residential settings”). 
Page 6 of 94 

Residential Postapplication: Potential residential postapplication exposure to adults and children from 

ornamental applications are expected to be negligible for the following reasons: 1) Activities such as 

pruning/thinning ornamentals or playing in and around ornamentals when residues may be present on 

the day of the application are unlikely to co-occur; 2) if present, leaf to skin residue transfer would be 

negligible because of the minimal frequency and duration of contact; 3) children young enough to 

exhibit hand-to-mouth behavior would not typically play in ornamental beds or trees. Based on the 

frequency of application and unlikely potential for postapplication exposure, residential postapplication 

risks were not quantitatively assessed; thus, there are no postapplication residential risk concerns for this 

use pattern. 

Based on the Agency's current practices, a quantitative postapplication inhalation exposure 

assessment was not performed for cyflufenamid at this time. If new policies or procedures are 

put into place, the Agency may revisit the need for a quantitative postapplication inhalation 

exposure assessment for cyflufenamid. 

Aggregate Risk: 

 

Acute: Acute exposures were not considered because an adverse effect attributable to a single 

dose was not identified. 

Chronic: Aggregate chronic risk is equivalent to chronic dietary risk. There is potential chronic 

exposure (≤1% of the cPAD) via the diet (food and drinking water) as determined in Section 5.4. 

Short- and Intermediate Term: There is potential short- and intermediate-term exposure to 

cyflufenamid via the dietary pathway (which is considered background exposure) and the 

residential pathway (which is considered the primary pathway). Since no dermal hazard was 

identified, the exposure pathways for adults include the oral (background) and inhalation 

(primary) routes. For children, the exposure pathway includes only the oral (background) route 

since 1) no dermal hazard was identified; 2) ornamentals are the only residential use; and 3) 

dermal, inhalation, and incidental oral exposure to children from treated ornamentals is 

considered to be negligible. All aggregate MOE’s are greater than 100; therefore, aggregate 

exposure is not of concern. 

Cancer: The aggregate cancer risk (food, water, and residential) is 9.7 x 10-7. 

Occupational Exposure/Risk: 

 

Agricultural Handlers: Occupational short-term (1 - 30 days) and intermediate-term (1 - 6 

months) dermal and inhalation exposures are expected from cyflufenamid handler activities 

associated with both the proposed agricultural and ornamental uses. Since no hazard was 

identified for the dermal route of exposure, non-cancer dermal risks were not assessed. 

HED used data from the Pesticide Handlers Exposure Database (PHED) Version 1.1 as presented 

in the PHED Surrogate Exposure Guide (8/98) to assess handler exposures (HED Science 

Advisory Council for Exposure (ExpoSAC) Standard Operating Procedure (SOP) No. 7, dated 

01/28/1999). A Margin of Exposure (MOE) greater than 100 for the inhalation route is deemed 
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adequate to protect occupational cyflufenamid handlers. All baseline inhalation scenarios (i.e., 

no respiratory protection) for handlers resulted in MOEs greater than the level of concern LOC 

(i.e., MOEs ≥ 100) and, therefore, are not of concern. The maximum exposure (MOE = 38,000) 

occurred from mixing/loading liquid concentrates for aerial applications to pome 

fruit/grapes/strawberries at the maximum application rate (0.022 lb ai/A). The cancer risks range 

from 5.0 x 10-9 to 1.2 x 10-7 assuming the workers wear labeled Personal Protective Equipment 

(PPE) (long-sleeved shirt, long-pants, and chemical resistant gloves). 

Agricultural Postapplication: Since no hazard was identified for the dermal route of exposure, 

occupational short- and intermediate-term non-cancer dermal risks were not assessed for 

postapplication activities. Based on the Agency's current practices, a quantitative postapplication 

inhalation exposure non-cancer assessment was not performed for cyflufenamid at this time. 

Using surrogate data and default assumptions, the cancer risks from agricultural postapplication 

activities range from 7.4 x 10-8 to 4.1 x 10-6 on day 0 (12 hours following application). Although 

cyflufenamid specific dislodgeable foliar residues (DFR) studies on grapes and ornamentals 

could be used to refine and mitigate the cancer risks for these scenarios, this assessment 

incorporates conservative parameters such as maximum application rates and assuming workers 

are exposed to “Day 0” cyflufenamid residue levels for 250 days/year even though only two 

applications per ornamental type per year can be made with a retreatment interval of 21 days. 

Environmental Justice Considerations: Potential areas of environmental justice concerns, to 

the extent possible, were considered in this human health risk assessment. Dietary and nondietary exposures were considered. 

Review of Human Research: This risk assessment relies in part on data from studies in which 

adult human subjects were intentionally exposed to a pesticide or other chemical. These studies 

(listed in Appendix C) have been determined to require a review of their ethical conduct, and one 

of these studies is also subject to review by the Human Studies Review Board. All of the listed 

studies have received the appropriate review. 

2.0 Regulatory Conclusions and Recommendations 

Provided revised Sections B (OPPTS 860.1200) and F (OPPTS 860.1550) are submitted, HED

can recommend for a conditional registration and permanent tolerances for the proposed uses of 

cyflufenamid on pome fruit, cucurbits, and the fruit subgroups 13-07F and 13-07G, except 

cranberry. Additional data are needed as conditions of registration as outlined in Section 2.1 

below. The specific tolerance recommendations are discussed in Section 2.2, and label 

modifications are discussed in Section 2.3. 

Although not a requirement since there is a multiresidue method, the Agency is requesting that 

the petitioner revise the liquid chromatography/tandem mass spectrometric detection 

(LC/MS/MS) enforcement method (Method 070276) to provide two mass ion transitions for 

analysis of cyflufenamid. 
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2.1 Data Deficiencies/Conditions of Registration 

The following must be provided prior to a tolerance being established or registration 

allowed: 

 

860.1200 Directions for Use

A revised Section B is requested prohibiting the addition of a spray adjuvant to the spray 

solution and including plant-back intervals (PBIs) of 30 days for small grains and leafy 

vegetables and 365 days for all other crops not on the label. 

860.1550 Proposed Tolerances

A revised Section F must be submitted to reflect the tolerances and correct commodity 

definitions as listed in Table 2.2.4.

The following data are required as a condition of registration: 

TOXICOLOGY

870.6200 Neurotoxicity Battery (Acute Studies) 

The acute neurotoxicity screening battery is required to fulfill current 40 CFR Part 158 

data requirements. 

RESIDUE CHEMISTRY

860.1300 Nature of the Residue – Plants

To upgrade the submitted apple metabolism study (MRID 47620805), details of the inlife and analytical phases of the study along with quantitative raw data and sample 

storage information must be submitted.

The following data should be submitted with future uses: 

RESIDUE CHEMISTRY

860.1300 Nature of the Residue – Plants

If additional crops are proposed in the future, the ChemSAC recommends that a 

metabolism study be conducted on a root crop and that the radiolabels include a 

radiolabel on the cyclopropyl ring. 

860.1480 Meat/Milk/Poultry/Eggs

For livestock, any feeding study conducted in the future for additional uses should 

determine cyclopropylcarboxylic acid (CPCA). [CPCA should be monitored in future 

ruminant feeding studies (for registration requests that include additional livestock 

feedstuffs) in lieu of a cyclopropyl labeled metabolism study (ROCKS memo, 

DP#377139, G. Kramer, 5/18/2010).] 
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2.2 Tolerance Considerations 

2.2.1 Enforcement Analytical Method 

Adequate multiresidue methods test data for cyflufenamid were submitted. Acceptable 

recoveries of cyflufenamid from a non-fatty matrix (grape) were achieved under Protocol E. 

Acceptable recoveries from a fatty matrix (milk) were also achieved under Protocol F. HED 

recommends that FDA multiresidue methods be used as the primary enforcement method. The 

submitted data will be forwarded to the U.S. FDA for further evaluation. 

Adequate residue analytical methodology is available for tolerance enforcement. The 

LC/MS/MS method (Method 070276) was submitted for the determination of cyflufenamid 

residues in/on pome fruit, cucurbit vegetables, grapes, and strawberries. The proposed 

enforcement method (Method 070276), in combination with the FDA multiresidue method, 

meets the OPPTS Residue Chemistry Test Guidelines for acceptable tolerance enforcement 

methods (SOP Number ACB-019). 

 

Method 070276 monitors one mass ion transition. Although not a requirement since there is an 

adequate multiresidue method, the Agency is requesting that the petitioner revise the LC/MS/MS 

enforcement method (Method 070276) to provide two mass ion transitions for analysis of 

cyflufenamid. 

An enforcement method for livestock commodities is not needed because tolerances for 

cyflufenamid residues of concern in meat, milk, poultry, and eggs are not required to support the 

proposed uses based on the results of the goat metabolism study and the calculated dietary 

burden. 

2.2.2 International Harmonization 

There are currently no maximum residue limits (MRLs) established by Codex, Canada, or 

Mexico for cyflufenamid. An International Residue Limit Status sheet is attached (Appendix D). 

2.2.3 Recommended Tolerances 

HED recommends for the following tolerances and residue definition: 

Tolerances are established for residues of the fungicide cyflufenamid, including its 

metabolites and degradates, in or on the commodities in the table below. Compliance 

with the tolerance levels specified below is to be determined by measuring only 

cyflufenamid, [N(Z)]-N-[[(cyclopropylmethoxy)amino][2,3-difluoro-6-

(trifluoromethyl)phenyl]methylene]benzeneacetamide. 
Page 10 of 94 

Apple, wet pomace...............................................................0.10 ppm 

Berry, low growing, subgroup 13-07G, except cranberry ...0.20 ppm 

Fruit, pome, group 11...........................................................0.06 ppm 

Fruit, small vine climbing, subgroup 13-07F, 

 except fuzzy kiwifruit ........................................................0.15 ppm 

Grape, raisin .........................................................................0.30 ppm 

Vegetable, cucurbit, group 9 ................................................0.07 ppm 

Note: The petitioner voluntarily withdrew the proposed use on cranberry. 

 

2.2.4 Revisions to Petitioned-For Tolerances 

Table 2.2.4 compares proposed and recommended tolerance levels. The recommended tolerance 

levels, including increases for pome fruit and cucurbits, are based on the submitted magnitude of 

the residue data and the Agency’s tolerance spreadsheet as specified by the Guidance for Setting 

Pesticide Tolerances Based on Field Trial Data SOP. 

Table 2.2.4. Tolerance Summary for Cyflufenamid 

Commodity Proposed Tolerance 

(ppm) 

Recommended 

Tolerance (ppm) 

Comments 

Correct Commodity Definition

Pome fruit crop group 11 0.05 0.06 Fruit, pome, group 11 

Apple, wet pomace 0.10 0.10 Adequate apple processing data are 

available. 

Cucurbit crop group 9 0.05 0.07 Vegetable, cucurbit, group 9 

Small fruit vine climbing 

subgroup except fuzzy 

kiwifruit; crop subgroup 

13-07F 

0.15 0.15 Fruit, small vine climbing, subgroup 

13-07F, except fuzzy kiwifruit 

Grape, raisin 0.30 0.30 Adequate grape processing data are 

available. 

Berry, low growing 

subgroup 13-07G 

0.20 0.20 Berry, low growing, subgroup 13-

07G, except cranberry 

2.3 Label Recommendations 

2.3.1 Recommendations from Residue Reviews 

A revised Section B/label is requested for Miltrex® 10 SC Fungicide (EPA Reg. No. 8033-

pending) prohibiting the addition of a spray adjuvant to the spray solution and including plantback intervals (PBIs) of 30 days for small grains and leafy vegetables and 365 days for all other 

crops not on the label. 

2.3.2 Recommendations for Worker Safety 

There are no specifications for amount of sufficient finished spray volumes for the ornamental 

uses. However, correspondence with the registrant indicated that the spray applications are made 
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in 20 - 200 gal/A. HED recommends that this language is added to the label for 

CYFLUFENAMID 10 SC Fungicide (EPA Reg. No. 8033-pending) for clarification purposes. 

2.3.3 Recommendations for Residential Safety 

It should be noted that the proposed label states “Not for homeowner use”; however, HED 

assessed residential handler exposure activities for the ornamental uses because there is a 

potential that homeowners could apply this product. HED recommends that the label language 

be revised to clarify the specific type of applicator and setting (i.e., “applications made only by 

licensed pest control operators in commercial and residential settings”). 

3.0 Ingredient Profile 

Cyflufenamid belongs to a new fungicide class, amidoximes, for which the pesticidal mode of 

action is yet to be defined. Cyflufenamid is active against all strains of powdery mildew, 

including those strains resistant to demethylation inhibitors and to strobulurin-type and 

benzimidazole-type fungicides. It has shown both protectant and curative activity on powdery 

mildew. 

 

Nippon Soda Company, Ltd. has proposed uses for cyflufenamid on cucurbit vegetables (Crop 

Group 9), pome fruit (Crop Group 11), small fruit vine climbing except fuzzy kiwifruit 

(Subgroup 13-07F), low growing berry (Subgroup 13-07G), except cranberry, and outdoor 

landscape and outdoor nursery ornamentals. 

Cyflufenamid is formulated as suspension concentrates containing 0.85 lb ai/gal (10% ai). 

Cyflufenamid is applied as postemergence broadcast foliar sprays using ground or aerial 

equipment. Application through any type of irrigation system is prohibited. A maximum of two 

applications can be made to agricultural crops and ornamentals for a maximum of 0.022 lb 

ai/A/growing season (cucurbits), 0.044 lb ai/A/growing season (other agricultural crops), and 

0.044 lb ai/A/year (ornamentals). For agricultural crops, retreatment intervals (RTIs) are 7 or 14 

days and preharvest intervals (PHIs) are 0, 3, or 14 days. Retreatment intervals for ornamentals 

are 14-21 days. 

3.1 Structure and Nomenclature

Table 3.1. Cyflufenamid Nomenclature. 

Chemical Structure 

F

F

N

H

N

O

O

CF3
Page 12 of 94 

Table 3.1. Cyflufenamid Nomenclature. 

Empirical Formula C20H17F5N2O2

Common Name Cyflufenamid 

Company experimental name NF-149 

IUPAC Name (Z)-N-[α-(cyclopropylmethoxyimino)-2,3-difluoro-6-(trifluoromethyl)benzyl]-2-

phenylacetamide 

CAS Name [(N(Z)]-N-[[(cyclopropylmethoxy)amino][2,3-difluoro-6-

(trifluoromethyl)phenyl]methylene]benzeneacetamide 

CAS Registry Number 180409-60-3 

End-use product (EP) MILTREX® 10 SC Fungicide 

(0.85 lb ai/gal suspension concentrate; EPA Reg. No. 8033-RNG) 

Chemical Class Fungicide/amidoxime 

Known Impurities of Concern None 

3.2 Physical/Chemical Characteristics

Table 3.2. Physicochemical Properties of Cyflufenamid (Technical Grade of the Active Ingredient). 

Parameter Value Reference 

Molecular weight 412.36 g/mole Not applicable 

Melting point/range 61.5-62.5 oC Administrative Document for 

Cyflufenamid: Petition for 

Food Crop Tolerances for the 

Cucurbits Crop Group, the 

Pome Fruit Crop Group, 

Grapes [and Other Climbing 

Vine Small Fruit (except Fuzzy 

Kiwifruit)], and Strawberries 

(and Other Low Growing 

Berries), dated 11/28/08 

pH 6.2 (1% w/w solution) 

Density 1.347 g/cm3 at 20 oC 

Water solubility 0.80 mg/L at pH 6.3-6.8 and 10 oC 

0.52 mg/L at pH 6.3-6.8 and 20 oC 

0.047 mg/L at pH 6.3-6.8 and 30 oC 

0.014 mg/L at pH 4 and 20 oC 

0.12 mg/L at pH 10 and 20 oC 

Solvent solubility (20°C to 25°C) Not available 

Vapor pressure 3.54 x10-5 Pa at 20 oC 

Dissociation constant, pKa 12.08 at 20 oC 

Octanol/water partition coefficient, 

Log(POW) at 20 oC 

4.68 at pH 4.05 

4.70 at pH 6.75 

4.55 at pH 9.95 

UV/visible absorption spectrum Neutral – λmax 207, 238 nm 

Acidic – λmax 207, 238, 361 nm 

Basic – λmax 220, 240 nm 

3.3 Summary of Existing/Proposed Uses 

There are no existing uses in the U.S. Cyflufenamid is registered in Japan, Korea, and several 

European Union (EU) countries. 

Nippon Soda has proposed uses on agricultural crops (cucurbit vegetables, grapes and other vine 

climbing small fruits, pome fruit, and strawberries and other low growing berries, except 

cranberry) and ornamentals as summarized in Table 3.3 below. The formulation for agricultural 

crops is MILTREX® 10 SC Fungicide (EPA Reg. No. 8033-pending), a 0.85 lb ai/gal suspension 

concentrate (SC) formulation. The formulation for ornamental uses is CYFLUFENAMID 10 SC 
Page 13 of 94 

Fungicide (EPA Reg. No. 8033-pending), which is also a 0.85 lb ai/gal SC formulation. 

The submitted label for Miltrex® 10 SC Fungicide (EPA File Symbol 8033-RNG) is adequate to 

allow evaluation of the residue data relative to the proposed uses. Refer to Section 2.3 for 

recommended modifications to the proposed labels. 

Table 3.3. Summary of Directions for Use of Cyflufenamid 

Applic. 

Timing, Type, 

and Equip. 

Formulation 

[EPA Reg. 

No.] 

Applic. 

Rate (lb 

ai/A) 

Max. No. 

Applic. per 

Growing 

Season 

Max. Seasonal 

Applic. Rate 

(lb ai/A) 

PHI 

(days)

Use Directions and 

Limitations1 

Cucurbit Vegetables: Pumpkin, Squash (summer and winter), Watermelon, and other Melons such as Chayote (fruit), 

Chinese waxgourd (Chinese preserving melon), Citron melon, Cucumber, Gherkin, Gourd (edible), Momordica spp., 

Muskmelon (hybrid and/or cultivars of Cucumis melo including true cantaloupe, cantaloupe, casaba, chreshaw melon, 

golden pershaw melon, honeydew melon, honey balls, mango melon, Persian melon, pineapple melon, Santa Claus 

melon, and snake melon) 

Postemergence 

Foliar spray 

Ground, aerial 

0.85 lb/gal 

SC 

[8033-RNG] 

0.011 2 0.022 0 

Applications should begin at 

first sign of disease 

development. Do not apply 

more than once every 7 days. 

Apply in minimum spray 

volumes of 5 GPA by air or 20 

GPA by ground. 

Grapes; Amur river grape; Gooseberry; Kiwifruit, hardy; Maypop; Schisandra berry; and cultivars, varieties, and/or 

hybrids of these 

Postemergence 

Foliar spray 

Ground, aerial 

0.85 lb/gal 

SC 

[8033-RNG] 

0.011-

0.022 2 0.044 3 

Applications should begin at 

first sign of disease 

development. Do not apply 

more than once every 7 days at 

the low rate and 14 days at the 

high rate. Apply in minimum 

spray volumes of 5 GPA by air 

or 20 GPA by ground. 

Pome Fruit: Apple, Pear, Crabapple, Loquat, Mayhaw, Quince, Oriental pear 

Postemergence 

Foliar spray 

Ground, aerial 

0.85 lb/gal 

SC 

[8033-RNG] 

0.022 2 0.044 14 

Applications should begin at 

first sign of disease 

development. Do not apply 

more than once every 14 days. 

Apply in minimum spray 

volumes of 10 GPA by air or 

50 GPA by ground. 

Strawberries and other low growing berries except cranberry: Bearberry; Bilberry; Lowbush Blueberry; Cloudberry; 

Lingonberry; Muntries; Partridgeberry; and cultivars, varieties, and/or hybrids of these 

Postemergence 

Foliar spray 

Ground, aerial 

0.85 lb/gal 

SC 

[8033-RNG] 

0.011-

0.022 2 0.044 0 

Applications should begin at 

first sign of disease 

development. Do not apply 

more than once every 14 days. 

Apply in minimum spray 

volumes of 10 GPA by air or 

20 GPA by ground. 

Outdoor Landscape and Outdoor Nursery Ornamentals2
Page 14 of 94 

Table 3.3. Summary of Directions for Use of Cyflufenamid 

Applic. 

Timing, Type, 

and Equip. 

Formulation 

[EPA Reg. 

No.] 

Applic. 

Rate (lb 

ai/A) 

Max. No. 

Applic. per 

Growing 

Season 

Max. Seasonal 

Applic. Rate 

(lb ai/A) 

PHI 

(days)

Use Directions and 

Limitations1 

Postemergence 

Foliar spray 

Ground, aerial 

0.85 lb/gal 

SC 

[8033-

pending] 

0.011-

0.022 2 per year 0.044 per year NA 

Apply in sufficient finished 

spray volume appropriate for 

the size of the plant and amount 

of foliage. Use the higher rates 

and shorter interval under high 

disease conditions. 

HED assumed applications are 

made by groundboom, airblast, 

backpack, hose-end sprayer or 

low pressure hand wand. 

The retreatment interval is 14-

21 days. 1

Restrictions: 

 Application of Miltrex® 10 SC Fungicide through irrigation equipment is prohibited. 

A restricted-entry interval (REI) of 12 hours is proposed. 

For disease resistance management, the number of sprays of Miltrex® 10 SC Fungicide per crop is not to 

exceed 50% of the total number of sprays for powdery mildew. The label recommends that the product be 

alternated with other mode of action fungicides. 

There are no rotational plant-back restrictions listed on the submitted draft label for Miltrex® 10 SC 

Fungicide. 

2 The outdoor ornamental and nursery crops include abelia, acalypha, achillea, ageratum, amelanchier, amorpha, 

aster, azalea, barberry, begonia, bellflower, bittersweet, buckeye, buttonbush, California poppy, catalpa, flowering 

cherry, horse chestnut, cosmos, flowering crabapple, crepe-myrtle, dahlia, delphinium, dogwood, elm, euonymus, 

fleabane, gaillardia, gardenia, geranium, gerbera daisy, ornamental gourd, grape leaf ivy, hackberry, hawthorn, 

hibiscus, holly, hollyhock, honeysuckle, lilac, locust, maple, mock-orange, mountain laurel, oak, pansy, flowering 

pear, petunia, phlox, photinia, privet, rhododendron, rose, salvia, sedum, snapdragon, sycamore, sunflower, trumpet 

creeper, viburnum, walnut, willow and zinnia. 

4.0 Hazard Characterization and Dose-Response Assessment

4.1 Toxicology Studies Available for Analysis 

The toxicology database for the new active ingredient, cyflufenamid, is considered adequate for 

risk assessment in support of the current registration action under FIFRA Section 3 for food use. 

Toxicity studies submitted in support of registration are detailed in the following section and a 

brief summary of the findings is discussed in Section 4.3, Toxicological Effects. 

Data from the following studies were used to evaluate the hazard potential of cyflufenamid: 

• Acute: Acute oral toxicity of cyflufenamid, technical and its metabolite/degradate 149-

(E)-FB in rats; acute dermal, rat; acute eye inhalation, rat; acute eye irritation, rabbit; 

acute dermal irritation, rabbit; and dermal sensitization, guinea pig. A waiver request for 

the acute neurotoxicity screen was submitted. 

• Subchronic: 13-week oral, rat; 13-week oral, mouse; 13-week oral, dog; 28-day dermal, 
Page 15 of 94 

rat; and subchronic neurotoxicity, rat. 

• Chronic: 52-week oral, dog; 108-week oral, mouse; 2-year oral/carcinogenicity, rat. 

• Reproduction/developmental: Developmental toxicity, rabbit; developmental 

toxicity/one-generation reproduction, rat; and two-generation reproduction, rat. 

• Other: 6 genotoxicity screens (including 1 isomer), 3 metabolism studies in rats, 2 

immunotoxicity studies (mouse and rat) and 3 mechanistic toxicology studies. 

4.2 Absorption, Distribution, Metabolism, & Elimination (ADME) 

A difference in the excretion pattern between sexes was noted in the rat metabolism study. The 

rate of urinary excretion in males was greater than twice that of females. Consequently, fecal 

excretion was less in males (66% administered dose) and higher in females (81%). Biliary 

excretion was greater in females than males indicating increased absorption in female rats. A 

substantial proportion of the biliary radioactivity was ultimately eliminated in the feces of rats 

treated with a single low dose of cyflufenamid, indicating substantial enterohepatic recirculation. 

There was no substantial difference in excretion pattern between single and repeat doses of 

cyflufenamid but absorption was greater in rats treated with a single low dose (10 mg/kg) than a 

single high dose (200 mg/kg). 

Overall tissue accumulation of radioactivity was low; less than 1% was present 168 hr postdosing. Concentrations of radioactivity were highest in the liver, kidney and erythrocytes and fat 

(of females treated with 200 mg/kg). Especially long half-lives (t1⁄2) were noted for uterus, ovary 

and fat in females and red blood cells in both sexes. The elimination half-life of plasma was 14-

34 hrs while it exceeded 70 hours in erythrocytes. This longer t1⁄2 may be explained by the 

affinity of fluorinated phenyl moieties for membranes of red blood cells. 

Following administration of either [fluorinated phenyl-U-14C] or [cyclopropyl-2,3-14C]NF-149, 

the major metabolite identified in urine was 149-F1 (5-14% of the administered dose). (Refer to 

Appendix B for chemical names and structures). Treatment with β-glucuronidase or sulphatase 

showed that urinary metabolites were, for the most part, not conjugated. No unchanged parent 

was detected in urine. The major metabolite in feces was 149-F-3-OH-4-OH-B (11-27% 

administered dose). Unchanged parent accounted for ~5% of administered dose in animals 

treated with 10 mg/kg and increased as absorption became saturated at the higher and 

consecutive doses; unchanged cyflufenamid represented ~30% of the administered dose in rats 

given 10 mg/kg/day for 14 days. Biliary metabolites were qualitatively similar regardless of the 

dose and suggested extensive hepatic metabolism including glucuronidation. 

The proposed metabolic pathways, based on the observed excreted metabolites in rats 

administered radiolabeled cyflufenamid, are pictured in Figure 4.2. In one pathway, 

cyflufenamid is hydrolyzed to 149-F which is reduced to the amidine, 149-F1, and then 

subsequently deaminated to form 149-F6. In the other main pathway, 149-F-3-OH-4-OH-B was 

formed by di-hydroxylation of the non-fluorinated phenyl ring and subsequently converted to the 

methoxy derivative. Hydroxylation of the α position occurred as a minor pathway yielding 149-

F-3-OH-B and 149-F-4-OH-B. 149-F4B was glucuronidated or cyclized to the oxadiazole, 149-

F12. 
Page 16 of 94 

Figure 4.2 

4.2.1 Dermal Absorption 

A non-guideline in-vitro study was submitted which provides information on the dermal 

penetration of cyflufenamid (NF-149) following a single application to excised human skin of 

[

14C]NF-149 in a SC (suspension concentrate) formulation at two dose levels. At 1000 μg/cm2

, 

the total absorbed dose was only 1.14% of the applied dose (AD), almost entirely recovered in 

the stratum corneum (1.11% AD). The absorption rate was 0.0118 μg/cm2/h. At 0.136 μg/cm2, 

the total absorbed dose was 13.71% AD, almost entirely isolated in the stratum corneum

(12.93% AD) and the absorption rate was 0.00005 μg/cm2/h. Total recovery was 93% at each 

dose. In the absence of a dermal absorption study and an in-vitro study in excised rat skin, this 

study cannot be relied upon to provide a dermal absorption factor (DAF) for this risk assessment. 

Since an acceptable/guideline dermal absorption study in the rat was not available, a dermal 

absorption factor was calculated as the ratio of the subchronic oral LOAEL, 117.4 mg/kg/day, to 

the dermal NOAEL, 1000 mg/kg/day, from the 28-day dermal toxicity study (LOAEL not 

established); the upper bound estimate of dermal absorption, DAF, is 12%. Note that liver 

parameters were measured in the 28-day dermal toxicity study but hepatotoxicity was not 

observed. Liver is the primary organ of cyflufenamid toxicity. 
Page 17 of 94 

4.3 Toxicological Effects 

In the mammalian toxicology database, the liver is the primary target organ for cyflufenamid 

toxicity. Across species, duration and gender, changes in weight, clinical chemistry and 

pathology indicate treatment-related perturbations in and adverse effects on liver function. 

Common, toxicologically significant changes in clinical chemistry include: increased alkaline 

phosphatase activity; increased gamma glutamyl transferase activity; increased cholesterol and 

triglycerides; increased alanine and aspartate transferases; increased urea nitrogen and increased 

total protein. Increased liver weight is often accompanied by periacinar hepatocytic hypertrophy 

and vacuolation. Fatty liver changes observed in the subchronic and chronic mouse studies may 

be evidence of cyclopropane carboxylic acid (CPCA) toxicity. 

Thyroid effects due to treatment with cyflufenamid were seen only in the rat. Increased 

follicular cell hypertrophy (as well as increased organ weight) was noted in the 90-day 

subchronic feeding study. Neoplastic thyroid follicular adenomas were noted in the 2-year 

carcinogenicity study. The submitter postulated that thyroid changes were considered to be 

secondary to a treatment-related increase in metabolic activity of the liver but sufficient 

mechanistic data to support this hypothesis were not submitted. 

Kidney effects related to treatment were observed in the subchronic and chronic rat studies. 

Increased kidney weight was accompanied by tubular vacuolation and slight decreases in sodium 

and chloride concentrations. 

Treatment-related cardiotoxicity was noted in the rat and mouse feeding studies. Observed 

myocardial vacuolation and lipidosis can be attributed to decreased lipid metabolism; 

cyflufenamid caused an approximately 50% inhibition of carnitine palmitoyltransferase in both 

rat and mouse heart microsomal fractions in a non-guideline mechanistic study. Carnitine 

palmitoyltransferase is involved in the transport of long chain fatty acids into the mitochondrial 

matrix for oxidation. Fatty acid oxidation is an important source of energy for ATP production 

in the mitochondria. 

Cyflufenamid-induced brain vacuolation was specific to the dog and not associated with any 

apparent clinical sign of neurotoxicity. Supplementary studies investigating this phenomenon 

determined that vacuolation was due to myelin edema affecting the white matter of the cerebrum 

and thalamus. Furthermore, this brain lesion was partially reversed after a 13-week recovery 

period (following 90-day exposure) and fully reversed after a 26-week recovery period. This 

effect was not observed in any other species. A subchronic neurotoxicity study in rats showed 

no evidence of neurotoxicity. 

Effects on reproductive organs and/or parameters were noted in several subchronic studies at 

doses greater than the respective LOAELs. Decreased uterus and cervix weights, adrenal 

cortical hypertrophy and reduced quality and quantity of spermatozoa were observed in dogs. 

Leydig cell hypertrophy was observed in rats and mice. It is unclear what toxicological 

significance should be ascribed to these findings since they may be secondary to systemic 

toxicity or hepatic enzyme induction. Mating performance and fertility in the P/F0 generation 

were both unaffected by treatment with cyflufenamid in the 2-generation reproductive toxicity 
Page 18 of 94 

study in rats. Sex ratio, sexual maturation, estrous cyclicity, sperm quantity and quality, mating 

performance and fertility, gestation and viability indices in the F1 generation were all unaffected 

by treatment. 

Study summaries of the acute, subchronic and chronic toxicity and genotoxicity for cyflufenamid 

are provided in Appendix A at the end of this document. 

Cyflufenamid has low acute toxicity via the oral, dermal and inhalation routes of exposure. 

Though slightly irritating to the eye, cyflufenamid is not a skin irritant or sensitizer under the 

conditions of the Guinea Pig Maximization Test. The Acute Toxicity Profiles are tabulated in 

Appendix A2. It is pertinent to note that some environmental degradates/metabolites are 

apparently more acutely toxic than the parent compound. Compound 149-F1, in particular, is 

classified in Toxicity Category II. However, since 149-F1 is a major urinary metabolite in rats 

administered cyflufenamid, its subacute – chronic toxicity is accounted for in the mammalian 

toxicology database. 

Cyflufenamid is classified as “likely to be carcinogenic to humans.” This was based on the 

presence of two tumor types in two species: thyroid follicular cell tumors in male rats and liver 

tumors in male mice. There is no concern for mutagenicity or clastogenicity. The unit risk, Q1

*

, 

of cyflufenamid based upon male mouse liver combined adenoma and carcinoma tumor rates is 

6.61 x 10-3 (mg/kg/day)-1 in human equivalents. Two non-guideline studies were submitted to 

address thyroid lesions but were not sufficient to support a carcinogenic mode of action. 

4.4 Safety factor for Infants and Children (FQPA Safety Factor) 

Based on the hazard and exposure data, the cyflufenamid risk assessment team has recommended 

that the FQPA Safety Factor be reduced to 1X because there is an adequate toxicity database for 

cyflufenamid and exposure data are complete or are estimated based on data that reasonably 

account for potential exposures. There is no evidence of susceptibility following in utero and/or 

postnatal exposure in the developmental toxicity studies in rats or rabbits, and in the 2-generation 

rat reproduction study. There are no residual uncertainties concerning pre- and postnatal toxicity 

and no neurotoxicity concerns. The chronic and cancer dietary (food and drinking water) 

exposure assessments are conservative. The dietary and residential assessments are based on 

reliable data and will not underestimate exposure/risk. Based on these data and conclusions, the 

FQPA Safety Factor can be reduced to 1X. 

4.4.1 Completeness of the Toxicology Database 

The toxicology database is complete with the exception of an acute neurotoxicity study (ACN, 

OPPTS 870.6200a) which is a new data requirement under 40 CFR Part 158 for registration of a 

pesticide (food and non-food uses). EPA has evaluated the available toxicity data for 

cyflufenamid and determined that an additional database uncertainty factor is not needed to 

account for potential neurotoxicity. The reasons follow: 
Page 19 of 94 

• An acute neurotoxicity screening test will unlikely yield a point of departure less than the 

chronic NOAEL of 4.4 mg/kg/day. At this level, there would be no risk concern based 

on acute dietary exposure. 

• In an acute oral toxicity study, adverse effects were noted on the day of administration 

(limit dose) but not thereafter; clinical signs of piloerection, hunched posture, unsteady 

gait, pallid extremities, increased salivation, ungroomed appearance and abnormal 

respiration were observed in the majority of animals receiving 5000 mg/kg and generally 

resolved by Day 2 of the study. 

• An acceptable, guideline subchronic neurotoxicity study was submitted. Repeat exposure 

to doses up to approximately 500 mg/kg/day did not elicit any neurotoxic effects as 

assessed in the functional observational battery, motor activity, neurohistopathology or 

brain morphometrics. 

• Cyflufenamid is not an apparently neurotoxic chemical based on clinical toxicity 

assessments incorporated within the developmental and chronic rat studies. In several 

short-term studies in rats (subacute and subchronic feeding, plaque-forming cell assay, 

one-generation pilot, developmental toxicity), no neurobehavioral signs were observed at 

the highest doses tested. While the relevant and reversible effect of brain vacuolation 

was observed in the subchronic dog study at approximately 70 mg/kg/day, it is observed 

in the absence of overt neurotoxicity and nowhere else in the toxicology database. 

In summary, while the results of the required acute neurotoxicity study may show an adverse 

effect following a single dose, there is no need to retain an UFDB, as any point of departure 

(POD) based on neurotoxic effects is likely to be at least 100 fold higher than the chronic RfD. 

Based on the available toxicity database and the Agency's current practices, the inhalation risk 

for cyflufenamid was assessed using an oral toxicity study. The Agency sought expert advice 

and input on issues related to this route to route extrapolation approach (i.e., the use of oral 

toxicity studies for inhalation risk assessment) from its Federal Insecticide, Fungicide, and 

Rodenticide Act Scientific Advisory Panel (SAP) in December 2009. The Agency received the 

SAP’s final report on March 2, 2010 

(http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The Agency is in the 

process of evaluating the SAP report and may, as appropriate, re-examine and develop new 

policies and procedures for conducting inhalation risk assessments, including route to route 

extrapolation of toxicity data. If any new policies or procedures are developed, the Agency may 

revisit the need for an inhalation toxicity study for cyflufenamid and/or re-examine the inhalation 

toxicity risk assessment. 

4.4.2 Evidence of Neurotoxicity 

Cyflufenamid is not an apparently neurotoxic chemical based on clinical observations of 

neurotoxicity during the conduct of developmental or chronic studies. No untoward 

neurobehavioral signs were observed at doses approaching the limit dose in any of the shortterm studies in rats or mice (subchronic oral, immunotoxicity, 28-day dermal) or chronic studies. 

No neurotoxic effects were observed during the subchronic neurotoxicity battery in which 

animals were dosed at systemically toxic dose levels (572 mg/kg/day). A requisite acute 

neurotoxicity screen has not been submitted for this new active ingredient; this requirement shall 

remain as a condition of registration. Myelin edema, diffuse vacuolation of white matter, was 
Page 20 of 94 

observed in dogs after 90 days of treatment with 76.2 mg/kg/day. This effect was not seen in the 

chronic dog study, largely in part, because the HDT was 17.3 mg/kg/day. Brain vacuolation may 

be regarded as a reversible effect since this lesion was less severe after a 13-week recovery 

period and absent after a 26-week recovery period (both following a 90-day treatment). Brain 

vacuolation may also be regarded as species-specific since there were no microscopic findings of 

the nervous system in either the rat or mouse. It is pertinent to note that neurological function 

was not altered in dogs treated with 76.2 mg/kg/day for 90 days. The endpoints selected for this 

risk assessment are protective of this effect seen in dogs. 

A developmental neurotoxicity study is not required at this time. 

4.4.3 Evidence of Sensitivity/Susceptibility in the Developing or Young Animal 

Neither the rat nor rabbit developmental studies identified teratogenic effects. There was no 

evidence of increased susceptibility in the submitted toxicology database. 

There is no concern for increased susceptibility to offspring following pre- and postnatal 

exposure to rats or in utero exposure in rabbits. Maternal NOAELS are clearly defined and do 

not exceed offspring values and are based on general systemic toxicity. The marginally higher 

incidence of incompletely ossified epiphyses and metacarpals/phalanges seen in rabbits may be 

associated with low fetal weight and are indicative of delayed embryo-fetal development. The 

combined offspring effects of decreased body weight and incomplete ossification are believed to 

be related to the observed maternal toxicity. Furthermore, the points of departure selected for all 

exposure scenarios are lower than those doses causing adverse effects in offspring. 

Maternal treatment with cyflufenamid had no developmental effects in rats. A dose-dependent 

reduction in fetal body weight was observed in rabbits treated with ≥ 60 mg/kg/day. A higher 

incidence of incompletely ossified epiphyses and metacarpals/phalanges was also observed at 

mid-dose and above. Both effects may be regarded as secondary to maternal toxicity (decreased 

body weight gain) rather than a direct effect upon the fetus by cyflufenamid. Cyflufenamid has 

no teratogenic potential up to the limit dose of 1000 mg/kg/day in rats and did not produce any 

developmental effects in rabbits at doses lower than the maternal LOAEL. Offspring toxicity 

was limited to reduced body weight and body weight gain at doses equal to those eliciting similar 

effects in the parental generations in the 2-generation reproductive toxicity study. 

4.4.4 Residual Uncertainty in the Exposure Database

There are no residual uncertainties in the exposure database. Since the dietary and non-dietary 

exposure estimates were based on several conservative assumptions, HED does not believe that 

the exposure estimates are underestimated. The chronic dietary assessment conducted with 

DEEM-FCID was a partially refined analysis. The assessment utilized average field trial 

residues for all crops. In addition, default processing factors were assumed for all commodities 

except for apple juice and grape juice where empirical processing factors were used. 100% crop 

treated was assumed for all commodities. The DEEM analysis also assumed that all drinking 

water will contain cyflufenamid at the highest EDWC levels modeled by EFED for ground water 

or surface water. For these reasons it can be concluded that the DEEM-FCID analysis does not 
Page 21 of 94 

underestimate risk from chronic exposure to cyflufenamid. Similarly, HED does not believe that 

the non-dietary occupational and residential exposures are underestimated because they are also 

based on conservative assumptions, including maximum application rates, labeled PPE, and 

standard values for unit exposures, acreage treated/amount handled.

4.5 Toxicity Endpoint and Point of Departure Selections 

The details for selecting toxicity endpoints and points of departure are presented in Appendix 

A3. An acute reference dose was not established as there were no adverse effects in the 

toxicology database which could be attributed to a single dose. The chronic reference dose was 

based on liver, thyroid and kidney effects observed in the combined chronic toxicity 

study/carcinogenicity study in rats. No dermal hazard was identified. The toxicity endpoint and 

point of departure observed in the single study, Prenatal Developmental Toxicity Study in 

Rabbits (decreased body weight gain and food consumption), are related to all other exposure 

scenarios and are protective of them (Section 4.5.4). The cyflufenamid risk assessment team has 

recommended that the FQPA safety factor be reduced to 1X (Section 4.4). 

4.5.1 Dose-Response Assessment 

An acute reference dose was not established. Absent the required acute neurotoxicity screen, no 

other effects observed in the toxicology database were attributable to a single dose. 

For chronic dietary exposure, a chronic reference dose of 0.04 mg/kg/day was selected for 

assessment of all populations based on a NOAEL of 4.4.mg/kg/day with evidence of 

hepatotoxicity at 22 mg/kg/day in the combined chronic toxicity/carcinogenicity study in rats. 

This provided the most sensitive endpoint available for dietary exposure; chronic dog and mouse 

exposure NOAELs were 4- and 15-fold greater, respectively. 

For short-and intermediate-term residential and occupational exposures involving incidental oral 

and inhalation exposure, the NOAEL of 5 mg/kg/day from the prenatal developmental study in 

rabbits (supplementary data) was selected. The LOAEL of 10 mg/kg/day was based on 

decreased body weight gain and food consumption. A reproductive study in rats was available 

for incidental oral exposures scenarios but had higher NOAELs (18 mg/kg/day). Therefore, the 

rabbit developmental study which was chosen for inhalation exposure (adults) was also used as 

an incidental oral exposure scenario endpoint to be protective of children. The available 

multigeneration study also better represented the intermediate exposure duration but, likewise, 

was superseded by the chosen short-term PoD (rabbit developmental study, NOAEL = 5 

mg/kg/day) which is more protective of longer term exposures. 

 

This single endpoint, NOAEL = 5 mg/kg/day based on decreased body weight gain and food 

consumption at 10 mg/kg/day, is conservative but justified by the observed dose-response 

relationship. The body weights of treated maternal rabbits were not significantly different from 

control animals at the end of the study. However, it is pertinent to note that the rabbits in the 

control group were significantly smaller than all treatment groups on Day 0. In this case, a 

decrease in body weight change is a stronger indicator of general systemic maternal toxicity than 

body weight. Notable body weight decrement was seen in the Day 6-18 interval and sustained 
Page 22 of 94 

throughout. Furthermore, overall body weight gains adjusted for gravid uterine weights were 

decreased by 107-171% in the treated groups compared to controls, reflecting maternal toxicity. 

A 28-day dermal toxicity study in the rat, in which neuropathology and hepatotoxicity were 

assessed, was available and showed no toxicity up to the limit dose. Since there were no 

concerns for developmental or neurological toxicities, dermal endpoints were not selected. 

Long-term dermal and inhalation exposures are not expected; therefore, endpoints were not 

selected. 

4.5.2 Recommendation for Combining Routes of Exposures for Risk Assessment 

Residential exposures (dermal, oral, and inhalation) can be combined if the toxicological effects 

are the same. Effects of decreased body weight, body weight gain and food consumption 

observed in the rabbit prenatal developmental study were selected for short-term/intermediateterm incidental oral and short-term/intermediate-term inhalation exposure for risk assessment; 

therefore, these routes of exposure can be combined to estimate aggregate risk. Since no hazard 

was identified in the dermal toxicology study and there are no concerns for developmental 

neurotoxicity, the dermal route of exposure need not be included in aggregate risk estimates. 

4.5.3 Classification of Carcinogenic Potential 

Cyflufenamid is classified as “likely to be carcinogenic to humans.” This was based on the 

presence of two tumor types in two species: thyroid follicular cell tumors in male rats and liver 

tumors in male mice. There is no concern for mutagenicity or clastogenicity. The unit risk, Q1

*

(mg/kg/day)-1, of cyflufenamid based upon male mouse liver combined adenoma and carcinoma 

tumor rates is 6.61 x 10-3 in human equivalents. 

4.5.4 Summary of Points of Departure and Toxicity Endpoints Used in Human Risk 

Assessment 

Table 4.5.4.1. Summary of Toxicological Doses and Endpoints for Cyflufenamid for Use in 

Dietary and Non-Occupational Human Health Risk Assessments 

Exposure/ 

Scenario 

Point of 

Departure 

Uncertainty/FQPA 

Safety Factors 

RfD, PAD, 

Level of 

Concern for 

Risk 

Assessment 

Study and Toxicological Effects 

Acute Dietary 

(All 

Populations) 

no hazard identified 

Chronic 

Dietary (All 

Populations) 

NOAEL= 

4.4 

mg/kg/day 

UFA= 10x 

UFH= 10x 

FQPA SF= 1x 

Chronic RfD = 

0.044 

mg/kg/day 

cPAD = 0.044 

mg/kg/day 

Combined Chronic Toxicity/ 

Carcinogenicity Study in Rats 

LOAEL = 22 mg/kg/day based on 

decreased body weight gain; increased 

thyroid/parathyroid weight, increased liver 

weight and centrilobular hepatocytic 

hypertrophy. 
Page 23 of 94 

Table 4.5.4.1. Summary of Toxicological Doses and Endpoints for Cyflufenamid for Use in 

Dietary and Non-Occupational Human Health Risk Assessments 

Exposure/ 

Scenario 

Point of 

Departure 

Uncertainty/FQPA 

Safety Factors 

RfD, PAD, 

Level of 

Concern for 

Risk 

Assessment 

Study and Toxicological Effects 

Incidental Oral 

Short-Term (1-

30 days) and 

IntermediateTerm (1-6 

months) 

NOAEL= 5 

mg/kg/day 

UFA= 10x 

UFH= 10x 

FQPA SF= 1x 

Residential 

LOC for MOE 

= 100 

Prenatal Developmental Study in Rabbits 

Maternal LOAEL = 10 mg/kg/day based 

on decreased body weight, body weight 

gain and food consumption. 

Dermal ShortTerm (1-30 

days) and 

IntermediateTerm (1-6 

months) 

No adverse effects were observed in the dermal toxicity study and there are no concerns for 

developmental or neurological toxicities; therefore, no hazards are expected from these exposure 

scenarios. 

Inhalation 

Short-Term (1-

30 days) and 

IntermediateTerm (1-6 

months) 

NOAEL = 5 

mg/kg/day 

UFA= 10x 

UFH= 10x 

FQPA SF= 1x 

Residential 

LOC for MOE 

= 100 

Prenatal Developmental Study in Rabbits 

Maternal LOAEL = 10 mg/kg/day based 

on decreased body weight, body weight 

gain and food consumption. 

Cancer (oral, 

dermal, 

inhalation) 

Classification: Likely to be carcinogenic to humans. Quantification of cancer risk was 

recommended. The Q1* value is 6.61 x 10-3 (mg/kg/day)-1. 

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and 

used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human 

exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = 

uncertainty factor. UFA = extrapolation from animal to human (interspecies). UFH = potential variation in 

sensitivity among members of the human population (intraspecies). FQPA SF = FQPA Safety Factor. PAD = 

population adjusted dose (a = acute, c = chronic). RfD = reference dose. MOE = margin of exposure. LOC = level 

of concern. 

Table 4.5.4.2. Summary of Toxicological Doses and Endpoints for Cyflufenamid for Use in 

Occupational Human Health Risk Assessments 

Exposure/ 

Scenario 

Point of 

Departure 

Uncertainty 

Factors 

Level of Concern 

for Risk 

Assessment 

Study and Toxicological Effects 

Dermal ShortTerm (1-30 

days) and 

IntermediateTerm (1-6 

months) 

No adverse effects were observed in the dermal toxicity study and there are no concerns for 

developmental or neurological toxicities; therefore, no hazards are expected from these exposure 

scenarios. 

Inhalation 

Short-Term (1-

30 days) and 

IntermediateTerm (1-6 

months) 

NOAEL = 5 

mg/kg/day 

UFA= 10x 

UFH= 10x 

Occupational LOC 

for MOE = 100 

Prenatal Developmental Study in Rabbits 

Maternal LOAEL = 10 mg/kg/day based 

on decreased body weight, body weight 

gain and food consumption. 
Page 24 of 94 

Table 4.5.4.2. Summary of Toxicological Doses and Endpoints for Cyflufenamid for Use in 

Occupational Human Health Risk Assessments 

Exposure/ 

Scenario 

Point of 

Departure 

Uncertainty 

Factors 

Level of Concern 

for Risk 

Assessment 

Study and Toxicological Effects 

Cancer (oral, 

dermal, 

inhalation) 

Classification: Likely to be carcinogenic to humans. Quantification of cancer risk was 

recommended. The Q1* value is 6.61 x 10-3 (mg/kg/day)-1. 

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and 

used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human 

exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = 

uncertainty factor. UFA = extrapolation from animal to human (interspecies). UFH = potential variation in 

sensitivity among members of the human population (intraspecies). FQPA SF = FQPA Safety Factor. PAD = 

population adjusted dose (a = acute, c = chronic). MOE = margin of exposure. LOC = level of concern. 

HED’s LOC for the MOE is defined by the uncertainty factors that are applied to the assessment. 

HED applies a 10X factor to account for interspecies extrapolation and a 10X factor to account 

for intraspecies sensitivity. Therefore, the total uncertainty factor that has been applied to the 

non-cancer risk assessment is 100 for residential and occupational exposure. Residential and 

occupational risks resulting in MOEs greater than or equal to 100 (HED’s LOC) provide a health 

protective margin of exposure.

4.5.5 Endocrine Disruption 

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor 

Screening Program (EDSP) to determine whether certain substances (including pesticide active 

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by 

a “naturally occurring estrogen, or other such endocrine effects as the Administrator may 

designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Between October 2009 and February 2010, EPA is issuing test orders/data call-ins for the first 

group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. 

This list of chemicals was selected based on the potential for human exposure through pathways 

such as food and water, residential activity, and certain post-application agricultural scenarios. 

This list should not be construed as a list of known or likely endocrine disruptors. 

Cyflufenamid is not among the group of 58 pesticide active ingredients on the initial list to be 

screened under the EDSP. Under FFDCA Sec. 408(p), the Agency must screen all pesticide 

chemicals. Accordingly, EPA anticipates issuing future EDSP test orders/data call-ins for all 

pesticide active ingredients. 
Page 25 of 94 

For further information on the status of the EDSP, the policies and procedures, the list of 67 

chemicals, the test guidelines and the Tier 1 screening battery, please visit our website: 

http://www.epa.gov/endo/. 

5.0 Dietary Exposure and Risk Assessment 

5.1 Metabolite/Degradate Residue Profile 

5.1.1 Summary of Plant and Animal Metabolism Studies 

PRIMARY CROPS: Metabolism studies were conducted in apples, cucumbers, and wheat 

uniformly labeled in the fluorinated phenyl ring (apple, cucumber, and wheat) or on the 2 and 3 

carbons of the cyclopropane ring (wheat). Positions of the radiolabeling are indicated below. 

F

F

N

H

N

O

O

CF3

*

F

F

N

H

N

O

O

CF3

*

*

Figure 5.1. 14C Labels in Metabolism Studies 

In primary crops, unchanged cyflufenamid was the major residue identified/confirmed and 

accounted for the bulk of total radioactive residues in various matrices including: apple fruit 

(66% of the total radioactive residues [TRR]), cucumber fruit (55-96% TRR), cucumber leaves 

(42-98% TRR), wheat forage (89-104% TRR), and wheat straw (33-65% TRR). Parent 

accounted for 16.9% TRR in apple leaves and 2-7% TRR in wheat grain at mature harvest. 

Residues of cyflufenamid appeared to be highest in samples collected at early sampling intervals 

and were observed to decrease at longer intervals. Several minor structurally related metabolites 

(<9% TRR) were detected, including the E-isomer of the parent compound. (The chemical 

names and structures of these compounds are depicted in Appendix B.) The apple and cucumber 

studies have shown that the bulk of the TRR was mainly surface residues which could be 

removed by rinsing. In addition, the cucumber study demonstrated that radioactive residues are 

not readily translocated from the soil into the aerial portion of the cucumber plant. 

ROTATIONAL CROPS: A confined rotational crop study was conducted on wheat (small 

grain), lettuce (leafy vegetable) and carrot (root vegetable) with [phenyl-U-14C]cyflufenamid. 

Although TRR accumulated at >0.01 ppm in some rotated crop matrices following treatment at 

1x the maximum proposed seasonal rate for rotatable crops, the analytical work performed did 

not identify the parent cyflufenamid or any of its putative and structurally related metabolites. 

The only residue component identified was Metabolite 149-F6 which was detected in mature 
Page 26 of 94 

carrot foliage from the 120-day PBI, accounting for 32.5% TRR (0.013 ppm). Carrot foliage 

was not planted at a longer PBI. 

RUMINANTS: A metabolism study was conducted on lactating goats with cyflufenamid 

uniformly labeled on the fluorinated phenyl ring. The metabolism in lactating goats is 

characterized by the oxidation of the parent compound at the 3- and 4-positions of the 

unsubstituted phenyl ring to form Metabolites 149-F-3-OH-B, 149-F-4-OH-B and 149-F-3-OH4-OH-B; and cleavage of the amide bond forming 149-F. Further cleavage of the oxime ether 

bond forms 149-F1, and subsequent oxidation yields 149-F6. The results at the high-dose 

feeding level of 13.3 ppm in goats showed that cyflufenamid was the major residue identified in 

fat accounting for 79.8% TRR. The parent was identified at lower levels in muscle (21.5% TRR) 

and milk (6.5% TRR). The parent was not detected in kidney or liver confirming the results 

from the low-dosed goat. The primary residue identified in milk and tissues other than fat was 

149-F1 accounting for 61.6% TRR in milk, 45.5% TRR in muscle, 55.5% TRR in kidney, and 

29.6% TRR in liver. Metabolite 149-F6 was also identified as a significant residue in muscle 

(29.9% TRR) and kidney (13.9% TRR), and as a minor residue in liver (8.6% TRR) and milk 

(4.3% TRR). Metabolite 149-F was identified as a minor residue in fat (1.4% TRR) and liver 

(7.4% TRR). Hydroxylated metabolites 149-F-4-OH-B and 149-F-α-OH-B were identified only 

in fat as minor residues (each ≤1.6% TRR). The isomer of cyflufenamid, 149-(E)-FB, was also 

only identified in fat, accounting for 2.5% TRR. 

POULTRY: There are no poultry feedstuffs associated with the proposed uses on pome fruit, 

cucurbit vegetables, vine climbing small fruits, and low growing berries. Therefore, data 

requirements for poultry metabolism are not relevant to this tolerance petition. 

RAT: The metabolism of [fluorinated phenyl-U-14C]NF-149 in the rat proceeded via two main 

pathways. In one pathway, NF-149 was hydrolyzed to 149-F and then reduced to the amidine 

149-F1. The 149-F1 was then deaminated to form 149-F6. In the other main pathway, 149-F-3-

OH-4-OH-B was formed by di-hydroxylation of the non-fluorinated phenyl ring and was 

subsequently converted to the methoxy derivative. The intermediate mono-hydroxylated 

metabolites 149-F-3-OH-B and 149-F-4-OH-B were also present. Hydroxylation at the α

position occurred as a minor pathway. A minor pathway proceeded via cleavage of the 

cyclopropylmethoxy moiety to form 149-F4B. The 149-F4B was then converted to a 

glucuronide conjugate. 149-F4B was also cyclized to the oxadiazole 149-F12. Conversion of 

NF-149 to the isomer 149-(E)-FB may represent a minor pathway. In the [cyclopropyl-2,3-

14C]NF-149 groups, one or two hydroxylations of NF-149 took place, and these reactions 

sometimes proceeded to the formation of a 2-(cyclopropylcarbonylamino)acetic acid. 

5.1.2 Summary of Environmental Degradation 

Cyflufenamid is not expected to be mobile and it does not break down by abiotic processes, such 

as hydrolysis and photolysis. In the environment, its major route of dissipation is likely through 

aerobic soil metabolism or runoff of soil to which cyflufenamid is absorbed. Aerobic 

metabolism studies indicate that cyflufenamid is moderately persistent. No degradation is 

observed under anaerobic conditions. The half-lives of cyflufenamid range from one week to 
Page 27 of 94 

several months in various aerobic soil and aquatic metabolism studies. In one aerobic soil 

metabolism study cyflufenamid is shown to persist for more than a year. 

Four degradation products of cyflufenamid are known, three major and one minor. The three 

major products are 149-F [N-cyclopropylmethoxy-2,3-difluoro-6-trifluoro-methylbenzamidine], 

149-F1 [2,3-difluoro-6-trifluoromethylbenzamidine], and 149-F11 [(Z)-N-(α- cyclopropyl 

methoxyimino-2,3-difluoro-6-trifluoromethylbenzyl)carbamoylacetic acid]. The minor 

degradation product identified is 149-F6 [2,3-difluoro-6-trifluoromethylbenzamide]. These 

degradation products are mobile to very mobile compounds and have short to very long halflives. 

It is believed that cyflufenamid may reach surface waters through spray drift and penetration of 

the canopy during application and foliar washoff to the soil followed by runoff of cyflufenamid 

absorbed soil. Field dissipation studies show that cyflufenamid may persist in the environment 

for more than a year, increasing the likelihood soil adsorbed cyflufenamid will contaminate 

surface water. In contrast, if cyflufenamid degrades rapidly to more soluble compounds that are 

mobile or highly mobile as some of the aerobic soil metabolism data indicate, it is possible that 

such degradates will contaminate surface water, as well as leach into groundwater. 

 

5.1.3 Comparison of Metabolic Pathways 

In primary crops, unchanged cyflufenamid was the major residue identified in various matrices. 

In rotational crops, parent cyflufenamid was not identified. The only residue component 

identified was Metabolite 149-F6, which was detected in mature carrot foliage. 

 

In drinking water, the residues of concern for risk assessment were parent, 149-F1, 149-F6, 149-

F11, and 149-F. 

In ruminants, parent was the major residue in fat. The primary residue identified in milk and 

tissues other than fat was 149-F1, formed from 149-F. Metabolite 149-F6 was also identified as 

a significant residue in muscle and kidney, and as a minor residue in liver and milk. The 

residues of concern in ruminants for risk assessment are cyflufenamid (Z-isomer), 149-F1, 149-

F6, and cyclopropane carboxylic acid (cyclopropylcarboxylic acid; CPCA). 

In the rat, the metabolism proceeded via two main pathways. In one pathway, parent (NF-149) 

was hydrolyzed to 149-F and then reduced to the amidine 149-F1. The 149-F1 was then 

deaminated to form 149-F6. In the other main pathway, 149-F-3-OH-4-OH-B was formed by dihydroxylation of the non-fluorinated phenyl ring and was subsequently converted to the methoxy 

derivative. The intermediate mono-hydroxylated metabolites 149-F-3-OH-B and 149-F-4-OH-B 

were also present. 

 
Page 28 of 94 

5.1.4 Residues of Concern Summary and Rationale 

Table 5.1.4.1. Compounds to be Included in the Cyflufenamid Risk Assessment and Tolerance 

Expression.1 

Matrix 

Residues included in Risk 

Assessment 

Residues included in Tolerance 

Expression for Compliance 

Monitoring 

Plants Primary Crop* Cyflufenamid** Cyflufenamid 

Rotational Crop Cyflufenamid Not required 

Livestock Ruminant Cyflufenamid, 149-F1, 149-F6, 

CPCA***

Not required

Poultry Not applicable Not applicable 

Drinking Water Cyflufenamid, 149-F1, 149-F6, 149-

F11, 149-F 

Not applicable 

1

Memo of Residues of Concern Knowledge-based Subcommittee [ROCKS], DP#377139, G.F. Kramer, Ph.D., 

5/18/2010 

Cyflufenamid = [N(Z)]-N-[[(cyclopropylmethoxy)amino][2,3-difluoro-6-

(trifluoromethyl)phenyl]methylene]benzeneacetamide. 

149-F1 = 2,3-difluoro-6-trifluoromethylbenzamidine. 

149-F6 = 2,3-difluoro-6-trifluoromethylbenzamide. 

149-F11 = (Z)-N-(α-cyclopropylmethoxyimino-2,3-difluoro-6-trifluoromethylbenzyl)carbamoylacetic acid. 

149-F = N-(cyclopropyl-methoxy-2,3-difluoro-6-trifluoromethylbenzamidine. 

CPCA = cyclopropane carboxylic acid. 

* for proposed crops only, additional data may be required for non-fruiting crops. 

** not including the E-isomer. 

*** tentative, these residues should be included in the feeding study (if required). 

Rationale:

Plants 

Primary Crops: The nature of the residue in plants is adequately understood for the presently 

proposed crops based on metabolism studies on apples, cucumbers, and wheat, pending 

submission of additional data and information for the submitted apple metabolism study. To 

upgrade the apple study, details of the in-life and analytical phases of the study along with 

quantitative raw data and sample storage information must be submitted. 

 

In primary crops, cyflufenamid is the residue of concern for the tolerance expression and for risk 

assessment since unchanged cyflufenamid was the major residue. For the primary crops, 

cyflufenamid parent can serve as an adequate measure of misuse based on its percentage of the 

TRR in the submitted metabolism studies. For dietary risk assessment purposes, ROCKS 

concluded that no metabolites need to be included due to their low levels relative to the parent 

compound. The E-isomer of cyflufenamid can also be excluded as a residue of concern based on 

its low percentage of the TRR and since the analytical enforcement method does not determine 

the E-isomer. 

HED does not have studies on three dissimilar crops since both the apple and cucurbit can be 

considered to be fruits. If additional crops are proposed in the future (which are not similar to 
Page 29 of 94 

apples, cucurbits, and wheat), additional metabolism data would be required; in that case, HED 

recommends that a metabolism study be conducted on a root crop. 

In the plant metabolism studies, although only one study (on wheat) included a radiolabel on the 

cyclopropyl ring, there was not a lot of cleavage of that ring so the submitted studies are 

adequate for the proposed crops. If a metabolism study is conducted in the future, the radiolabels 

should include a radiolabel on the cyclopropyl ring. 

Rotational Crops: The nature of the residue in rotational crops is adequately understood based 

on an acceptable confined rotational crop study conducted on wheat (small grain), lettuce (leafy 

vegetable) and carrot (root vegetable) with [phenyl-U-14C]cyflufenamid. Although TRR 

accumulated at >0.01 ppm in some rotated crop matrices following treatment at 1x the maximum 

proposed seasonal rate for rotatable crops, the analytical work performed did not identify the 

parent cyflufenamid or any of its putative and structurally related metabolites. The only residue 

component identified was Metabolite 149-F6 which was detected in mature carrot foliage from 

the 120-day PBI, accounting for 32.5% TRR (0.013 ppm). Carrot foliage was not planted at a 

longer PBI, so the rotational crop restriction on root crops needs to be set at the highest interval 

(365 days). Tolerances for inadvertent residues of cyflufenamid in rotational crops are not 

needed. The residue of concern for risk assessment is parent. Based on the rotational crop data, 

plant-back intervals of 30 days for small grains and leafy vegetables and 365 days for all other 

crops which are not on the label are needed for the Miltrex® 10 SC Fungicide label. 

Livestock 

Ruminants: The nature of the residue in ruminants is adequately understood based on an 

acceptable study conducted on lactating goats with cyflufenamid uniformly labeled in the 

fluorinated phenyl ring. In ruminants (lactating goats), cyflufenamid was a major residue in fat 

and muscle; 149-F1 was a major residue in milk, muscle, kidney, and liver; and 149-F6 was a 

major residue in muscle and kidney. Structure-activity relationship (SAR) analysis (DEREK) 

revealed the same alert for the parent compound and all of these metabolites, polyhalogenated 

benzene- alpha-2-mu-Globulin nephropathy (Table 5.1.4.2). However, this mode of action is not 

relevant to humans since male rats are unique in their accumulation of this low molecular weight 

protein in the kidney. 

 

Acute toxicity studies demonstrated that 149-F1 was 10X more acutely toxic than the parent 

compound. However, since 149-F1 is also a major metabolite in rats, sub-chronic/chronic 

toxicity studies with the parent are considered adequate to account for the toxicity of this 

metabolite. Due to structural similarities to the parent and in the absence of data to the contrary, 

metabolite 149-F6 is also of concern. 

Although not observed in the ruminant metabolism study (possibly due to the lack of a radiolabel 

in the cyclopropane ring), there is concern for the potential formation of cyclopropane carboxylic 

acid (CPCA). The concern for CPCA is for a severe form of liver toxicity, specifically 

microvesicular steatosis. The concern was identified in a ROCKS review of another pesticide 

(aminocyclopyrachlor). The chemicals that cause this toxicity are typically short chain, branched 

carboxylic acids. The alert is in DEREK and CPCA seems to be in the training set of chemicals 
Page 30 of 94 

that support the alert, so there is no question that it falls within the domain of applicability. The 

formation of metabolites bearing the cyclopropanecarboxyl group in livestock commodities 

could be elucidated by analysis of these compounds in a livestock feeding study (see below). 

A determination of the residues of concern in ruminants for the tolerance expression is not 

required at this time. A review of the livestock metabolism study and a livestock dietary burden 

calculation indicate that a cattle feeding study and tolerances for livestock commodities are not 

needed. 

For risk assessment, the residues of concern in ruminants are cyflufenamid (Z-isomer), 2,3-

difluoro-6-trifluoromethylbenzamidine (149-F1), 2,3-difluoro-6-trifluoromethylbenzamide (149-

F6) , and cyclopropane carboxylic acid (cyclopropylcarboxylic acid; CPCA). CPCA should be 

monitored in future ruminant feeding studies (for registration requests that include additional 

livestock feedstuffs) in lieu of a cyclopropyl labeled metabolism study. 

Poultry and Swine: There are no poultry or swine feed items associated with the proposed uses. 

Table 5.1.4.2. DEREK Alerts for Major Biodegradates. 

Compound Alerts 

Cyflufenamid 264 Polyhalogenated benzene. alpha-2-mu-Globulin nephropathy. 

149-F1 Number of matches = 1. 

149-F6 

149-F11 

149-F 

CPCA 253 Short chain alkyl carboxylic acid. Irritation (of the gastrointestinal 

tract). Number of matches = 1. 

546 Short chain fatty acid. Hepatotoxicity. Number of matches = 1. 

Drinking Water: Three degradation products (149-F, 149-F1, and 149-F11) accumulated to 

>10% in a number of the submitted laboratory studies. Another degradation product, 149-F6, 

had concentrations approaching 10% in some studies. In addition, some study durations were 

not long enough to see clear formation and decline patterns for 149-F6. 149-F6 is thus likely to 

be a major degradate if the study durations were increased. As discussed above, degradation 

products 149-F1 and 149-F6 are of concern for risk assessment. Due to structural similarities to 

the parent and in the absence of data to the contrary, degradation products 149-F11 and 149-F 

are also of concern. 

Recommended Tolerance Expression: 

The ROCKS recommends the following language for the tolerance expression for plant 

commodities: 

Tolerances are established for residues of the fungicide cyflufenamid, 

including its metabolites and degradates, in or on the commodities listed 

below. Compliance with the tolerance levels specified below is to be 
Page 31 of 94 

determined by measuring only cyflufenamid, [N(Z)]-N-

[[(cyclopropylmethoxy)amino][2,3-difluoro-6-

(trifluoromethyl)phenyl]methylene]benzeneacetamide. 

5.2 Food Residue Profile 

Crop Field Trials 

The submitted magnitude of the residue data, summarized in Table 5.2.1, are adequate for risk 

assessment and tolerance assessment. For all crops, the number and locations of field trials are 

adequate. Four foliar broadcast applications of a 10% SC formulation of cyflufenamid were 

made to each crop. No adjuvants were used. The Agency’s tolerance spreadsheet, as specified 

by the Guidance for Setting Pesticide Tolerances Based on Field Trial Data SOP, was used to 

determine appropriate tolerance levels. Based on the available data, all proposed tolerances are 

adequate, except for pome fruit and and cucurbit vegetables, for which tolerances of 0.06 and 

0.07 ppm, respectively, are recommended. 

Table 5.2. 1. Summary of Residues from the Crop Field Trials with Cyflufenamid. 

Crop matrix Total Applic. 

Rate 

 (lb ai/A) 

PHI 

(days) 

Residue Levels (ppm) 

n Min. Max. HAFT1 Median Mean Std. 

Dev. 

Cucurbit Vegetables (proposed use = 0.022 lb ai/A total application rate, 0-day PHI) 

Cucumber 0.044-0.046 0 12 <0.01 0.025 0.024 0.012 0.014 0.005 

Cantaloupe 0.044-0.045 0 12 <0.01 0.032 0.025 0.015 0.016 0.007 

Summer squash 0.044-0.046 0 10 <0.01 0.037 0.036 0.020 0.021 0.010 

Pome Fruit (proposed use = 0.044 lb ai/A total application rate, 14-day PHI)

Apple fruit 0.088-0.092 13-15 24 <0.01 0.033 0.026 0.011 0.014 0.006 

Pear fruit 0.088-0.090 14-15 12 0.014 0.044 0.037 0.022 0.024 0.009 

 Grapes and Small Vine Climbing Fruits (proposed use = 0.044 lb ai/A total application rate, 3-day PHI)

Grape fruit 0.088-0.091 3 24 0.0125 0.0835 0.0750 0.0356 0.0370 0.0181 

 Strawberries and Other Low Growing Berries 

(proposed use = 0.044 lb ai/A total application rate, 0-day PHI)

Strawberry fruit 0.088-0.091 0 16 0.015 0.134 0.118 0.072 0.072 0.032 1

 HAFT = Highest average field trial result.

Processing Studies 

The submitted apple and grape processing studies, summarized in Table 5.2.2, are acceptable. 

Residues of cyflufenamid concentrated in wet apple pomace (2.9x) but not in apple juice (0.3x) 

following processing of the RAC (whole apples) with quantifiable residues. Residues also 

concentrated in raisin (3.6x) but not in grape juice (0.2x) following processing of the RAC 

(grapes) with quantifiable residues. Following considerations of the observed processing factors 

and highest average field trial (HAFT) residues, the proposed tolerances of 0.10 ppm for wet 

apple pomace and 0.30 ppm for raisin are adequate. No tolerances are required for apple juice 

and grape juice. 
Page 32 of 94 

Table 5.2.2. Residue Data from Apple Processing Study with Cyflufenamid.

RAC Processed Commodity Total Rate 

(lb ai/A) 

PHI 

(days) 

Residues (ppm) 

[Average] 

Processing 

Factor 

Apple Fruit (RAC) 0.271 13 0.0305 -- 

Juice <0.01, <0.01 

[<0.01] 

0.3x 

Wet pomace 0.087, 0.089 

[0.088] 

2.9x 

Grape Fruit 0.271 3 0.106 -- 

Juice 0.029, 0.023 

[0.026] 

0.2x 

Raisins 0.385, 0.379 

[0.382] 

3.6x 

Storage Stability 

Adequate storage stability data for cyflufenamid are available to validate the storage conditions 

and durations of storage of samples from the crop field trial and processing studies. Corrections 

to residue values from the residue trials to account for dissipation during storage are not 

necessary. 

Meat, Milk, Poultry, and Eggs 

The only livestock feed item associated with the proposed uses is wet apple pomace, which can 

be fed to dairy cattle; there are no beef cattle, hog, or poultry feedstuffs associated with the 

proposed uses (Table 1 Feedstuffs, June 2008). A maximum reasonably balanced dietary burden 

of 0.025 ppm for cyflufenamid residues in dairy cattle was calculated based on residues in wet 

apple pomace. 

The results of the goat metabolism study and the calculated dietary burden indicate that there is 

no reasonable expectation of finite cyflufenamid residues of concern in meat, milk, poultry, and 

eggs [40 CFR 180.6(a)(3)] as a result of the proposed uses; therefore, a cattle feeding study and 

tolerances on livestock commodities are not required. HED will re-examine this decision in the 

event that additional livestock feedstuffs are proposed for registration in the future. Any feeding 

study conducted in the future for additional uses should determine cyclopropylcarboxylic acid 

(CPCA). 
Page 33 of 94 

Rotational Crops 

No tolerances are required for rotational crops. The confined rotational crop study indicated that 

no residues of concern are expected to occur in rotational crops with appropriate plant-back 

intervals. The proposed Section B/label must be revised to include plant-back intervals of 30 

days for leafy vegetables and small grains and 365 days for all other crops not on the label 

including root and tuber vegetables. 

5.3 Water Residue Profile 

Estimated surface water and groundwater concentrations are shown in Table 5.3.1. 

The dietary exposure assessment used the value of 4.68 ppb for chronic (non-cancer and cancer) 

assessments. The drinking water assessment is based on Tier I groundwater model simulations 

for all currently proposed cyflufenamid uses. (Cranberry is excluded since the petitioner 

voluntarily withdrew the use on cranberry). 

The drinking water assessment takes into account cyflufenamid, its isomer 149-(E)-FB [(E)-N-

(α-cyclopropylmethoxyimino-2,3-difluoro-6-trifluoromethylbenzyl)-2-phenylacetamide], and 

four known degradation products of equal toxicological concern, 149-F [N-cyclopropylmethoxy2,3-difluoro-6-trifluoro-methylbenzamidine], 149-F1 [2,3-difluoro-6-

trifluoromethylbenzamidine], 149-F11 [(Z)-N-(α-cyclopropylmethoxyimino-2,3-difluoro-6-

trifluoromethylbenzyl)carbamoylacetic acid], and 149-F6 [2,3-difluoro-6-trifluoromethylbenzamide]. These compounds are referred to collectively as total toxic cyflufenamid residues. 

Table 5.3.1 Summary of Estimated Surface Water and Groundwater Concentrations 

for Cyflufenamid.c

Scenario Surface Water Conc., ppb a Groundwater Conc., ppb b

Acute 1.14 4.68

Chronic (non-cancer) 0.03 Not available 

Chronic (cancer) 0.01 Not available 

a

 From the Tier II PRZM-EXAMS - Index Reservoir model. Input parameters are based on 2 applications at 0.022 

lbs ai/A/application to North Carolina apples using a percent cropped area (PCA) correction of 87%. 

b

 From theTier I SCI-GROW (Screening Concentration in Groundwater) model assuming a maximum use rate of 

two applications at 0.022 lb ai/A/application, a Koc of 10.5 mL/g, and an aerobic soil metabolism half-life of 314 

days. 

c

 DP#362954, Rochelle F. H. Bohaty, Ph.D., 5/3/2010. 
Page 34 of 94 

5.4 Dietary Risk Assessment 

5.4.1 Description of Residue Data Used in Dietary Assessment 

The chronic dietary analysis used for both non-cancer and cancer risk assessment assumed 

average field trial residues for all proposed crops. Empirical processing factors for apple juice 

and grape juice were used. (Refinements, made to upper bound exposure estimates specifically 

for use in the cancer assessment, were applied to both chronic and cancer assessments.) A 

separate tolerance was set for grape, raisin; therefore, the processing factor for this commodity 

was set at 1. For all other processed commodities, DEEMTM version 7.81 default processing 

factors were assumed. 

 

Table 5.4.1 summarizes the cyflufenamid residue levels and processing factors for the proposed 

crops used in the chronic dietary assessments. 

Table 5.4.1. Residue Data and Processing Factors used for Chronic Dietary Risk Assessment. 

Commodity Residues 

(Average; ppm) 

Processing Factors 

Fruit, pome, group 11 Apple-0.014 

Pear-0.024 

Apple, juice = 0.3 

Vegetable, cucurbit, group 9 Cucumber-0.014 

Cantaloupe-0.016 

Squash, Summer0.022 

Fruit, small vine climbing, subgroup 13-07F, 

except fuzzy kiwifruit 

Grape-0.037 Grape, juice = 0.2 

Berry, low growing, subgroup 13-07G, except 

cranberry 

Strawberry-0.072 

Grape, raisin 0.30 Grape, raisin = 1 

The drinking water residue levels used in the dietary assessment were estimated using Tier I 

SCI-GROW (Screening Concentration in Groundwater) modeling. The Estimated Drinking 

Water Concentration (EDWC) for total toxic cyflufenamid residues are ground water residues 

based on applications to low growing berries (except cranberry), ornamentals, pome fruit, and 

small climbing fruit vines. The EDWC for total toxic residues is 4.68 for both the chronic and 

cancer assessments. The water residues were directly incorporated in the DEEM-FCID into the 

categories “water, direct, all sources” and “water, indirect, all sources.” 

5.4.2 Percent Crop Treated Used in Dietary Assessment 

The chronic dietary analysis assumed that 100% of the crop was treated (100% CT). 

5.4.3 Acute Dietary Risk Assessment 
Page 35 of 94 

No toxic effects attributable to a single exposure to cyflufenamid have been identified; therefore, 

an acute reference dose (aRfD) has not been established and an acute dietary exposure 

assessment was not conducted. 

5.4.4 Chronic Dietary Risk Assessment 

A partially refined chronic dietary assessment was conducted. The assumptions of this dietary 

assessment included average field trial residues for all proposed crops. In addition, 100% crop 

treated (CT) was assumed. Empirical processing factors were used for apple juice and grape 

juice. A separate tolerance was set for grape, raisin; therefore, the processing factor for this 

commodity was set at 1. For all other processed commodities, DEEM version 7.81 default 

processing factors were assumed. A conservative EDWC derived through EFED modeling 

which is unlikely to underestimate the concentration of cyflufenamid in drinking water was 

utilized. The ground water EDWC (4.68 ug/L) was incorporated directly into the dietary 

assessment (DP# 362954, R. Bohaty, 5/3/2010). 

 

As shown in Table 5.4.6, the non-cancer chronic dietary (food and drinking water) exposure to 

cyflufenamid is below HED’s level of concern [i.e., <100% of the chronic Population Adjusted 

Dose (cPAD)] for the general U.S. population and all population subgroups. The chronic dietary 

exposure estimates are <1% of the cPAD for the general U.S. population and 1% of the cPAD 

for all infants (<1 year old), the most highly exposed population subgroup. 

5.4.5 Cancer Dietary Risk Assessment 

Cyflufenamid is a likely human carcinogen and requires a quantitative cancer risk assessment. 

The unit risk, Q1* = 6.61 X 10-3 (mg/kg/day)-1, of cyflufenamid is based upon male mouse liver 

combined adenoma and carcinoma tumor rates. The ground water EDWC (4.68 ug/L) was 

incorporated directly into the dietary assessment (DP# 362954, R. Bohaty, 5/3/2010). As shown 

in Table 5.4.6, the cancer dietary (food and drinking water) exposure estimate for the general 

U.S. population is 9.5 x 10-7, which is below HED’s level of concern (generally in the range of 

10-6). 

5.4.6 Summary Table 

Table 5.4.6. Summary of Dietary (Food and Drinking Water) Exposure and Risk for Cyflufenamid. 

Population Subgroup 

cPAD 

(mg/kg/day) 

Chronic Dietary Cancer 

Dietary 

Exposure 

(mg/kg/day) 

% 

cPAD 

Dietary 

Exposure 

(mg/kg/day) 

Risk 

Q* = 6.61 x 10-3

General U.S. Population 0.2 0.000144 <1 0.000144 9.5 x 10-7

All Infants (< 1 year old) 0.2 0.0004231

 1 

NA2 Children 1-2 years old NA 0.2 0.000330 <1 

Children 3-5 years old 0.2 0.000271 <1 
Page 36 of 94 

Table 5.4.6. Summary of Dietary (Food and Drinking Water) Exposure and Risk for Cyflufenamid. 

Population Subgroup 

cPAD 

(mg/kg/day) 

Chronic Dietary Cancer 

Dietary 

Exposure 

(mg/kg/day) 

% 

cPAD 

Dietary 

Exposure 

(mg/kg/day) 

Risk 

Q* = 6.61 x 10-3

Children 6-12 years old 0.2 0.000157 <1 

Youth 13-19 years old 0.2 0.000097 <1 

Adults 20-49 years old 0.2 0.000121 <1 

Adults 50+ years old 0.2 0.000136 <1 

Females 13-49 years old 0.2 0.000123 <1 

1

The population subgroup with the highest estimated chronic dietary (food + drinking water) exposure and risk is 

indicated by bold text. 

2

NA = not applicable 

6.0 Residential (Non-Occupational) Exposure/Risk Characterization

6.1 Residential Handler Exposure 

Although the proposed label for ornamental uses states “Not for homeowner use”, HED assessed 

residential handler exposure activities for the ornamental uses because there is a potential that 

homeowners could apply this product. HED recommends that the label language be revised to 

clarify the specific type of applicator and setting (i.e., “applications made only by pest control 

operators in commercial and residential settings”). 

Based on the use patterns, residential handlers could be exposed to cyflufenamid on a short-term 

basis. The short-term dermal risk scenarios were not necessary to assess because no hazard was 

identified for the dermal route of exposure. The short-term inhalation risk scenarios were 

assessed using the NOAEL of 5 mg/kg/day from the prenatal developmental study in rabbits. No 

inhalation absorption data are available; therefore, the toxicity by the inhalation route is 

considered to be equivalent to the estimated toxicity by the oral route of exposure. For the 

cancer assessment, a dermal absorption factor of 12% was utilized in the dermal exposure 

component of the lifetime average daily dose (LADD) while a Q1* of 6.61 x 10-3 (mg/kg/day)-1

was used to estimate the risk. Also, a body weight of 70 kg was used in all exposure estimates 

because the endpoints were not based on developmental effects. 

 

HED assessed short-term non-cancer inhalation risks and cancer risks for residential pesticide 

handlers in the following scenarios: 

• mixing/loading/applying sprays with backpack sprayers, 

• mixing/loading/applying sprays with low pressure handwand, and 

• mixing/loading/applying sprays with hose-end sprayers. 
Page 37 of 94 

Non-cancer risk estimates for residential handlers are included in Table 6.1.1. All inhalation 

handler scenarios resulted in MOEs greater than the LOC (MOEs ≥ 100) and, therefore, are not 

of concern. 

 

Cancer risk estimates for residential handlers are included in Table 6.1.2. Assuming that 

residential applicators apply cyflufenamid twice a year per label instructions, all handler 

scenarios resulted in cancer risks less than 1 x 10-6 assuming typical clothing (e.g., short-sleeve 

shirt, short pants, and no gloves). 

Table 6.1.1. Summary Of Short-Term Residential Handler Exposures And Risks 

Exposure Scenario Crop Grouping 

Application 

Ratea

(lb ai/gal) 

Amount 

Handled 

Dailyb

(gal/day) 

Baseline 

Inhalationc

Unit 

Exposure 

(μg/lb ai) 

Baseline 

Inhalation 

Dosed

(mg/kg/day) 

Baseline 

Inhalation 

MOEe

(LOC ≥100) 

Mixer/Loader/Applicator 

Backpack 

(PHED) Nursery/Ornamentals 0.0011 5 30 0.0000024 2,100,000 

Low Pressure 

Handwand 

(ORETF) 

Nursery/Ornamentals 0.0011 5 3.8 0.00000031 16,000,000 

Hose-End Sprayer 

(ORETF) Nursery/Ornamentals 0.0011 5 1.5 0.00000012 41,000,000 

a Application rates are the maximum application rates determined from proposed labels for cyflufenamid. Per label 

instructions and registrant correspondence: 0.0011 lb ai/gal = 3.4 oz conc/20 gal x 0.85 lb ai/gal x 1 gal/128 oz. 

b Amount handled per day values are HED estimates of amount handled per day based on ExpoSAC SOP No.12. 

c Inhalation: no respirator. 

d Inhalation dose = daily unit exposure (μg/lb ai) x application rate (lb ai/A) x area treated (A/day) x mg/1000 μg x 

100% inhalation absorption / body weight (70 kg adult). 

e Inhalation MOE = NOAEL (5.0 mg/kg/day) / inhalation daily dose (mg/kg/day), where LOC = 100. 
Page 38 of 94 

Table 6.1.2. Summary Of Residential Handler Exposures and Cancer Risks

Exposure Scenario Crop Grouping 

Application 

Ratea

(lb ai/gal) 

Amount 

Handled 

Dailyb

(gal/day) 

Baseline 

Dermalc

Unit 

Exposure 

(mg/lb ai) 

Baseline 

Inhalationd

Unit 

Exposure 

(μg/lb ai) 

Baseline 

Dermal 

Dose e

(mg/kg/day) 

Baseline 

Inhalation 

Dose e

(mg/kg/day) 

Baseline Average 

Daily Dose f

(mg/kg/day) 

Exposure 

Days g

(days/yr) 

Mixer/Loader/Applicator 

Backpack 

(PHED) Nursery/Ornamentals 0.0011 5 5.1 30 0.000049 0.0000024 0.000052 2 

Low Pressure Handwand 

(ORETF) Nursery/Ornamentals 0.0011 5 56 3.8 0.00054 0.00000031 0.00054 2 

Hose-End Sprayer (ORETF) Nursery/Ornamentals 0.0011 5 39 1.5 0.00038 0.00000012 0.00038 2 

a Application rates are the maximum application rates determined from proposed labels for cyflufenamid. Per label instructions and registrant 

ai/gal = 3.4 oz conc/20 gal x 0.85 lb ai/gal x 1 gal/128 oz. 

b Amount handled per day values are HED estimates of amount handled per day based on ExpoSAC SOP No.12. 

c Dermal: short pants, short sleeves, and no gloves. d Inhalation: no respirator. e Dose = daily unit exposure (μg/lb ai) x application rate (lb ai/A) x area treated (A/day) x mg/1000 μg (as needed) x100% inhalation absorpt

absorption / body weight (70 kg adult). 

f Average daily dose (ADD) (mg/kg/day) = dermal dose (mg/kg/day) + inhalation dose (mg/kg/day). g Exposure days: Based on label instructions: maximum of 2 applications per year. 

h Lifetime average daily dose (LADD) (mg/kg/day) = ADD x (2 days/yr x 50 yr) / (365 days/yr x 70 yr). i Cancer risk = LADD (mg/kg/day) x Q* of 6.61 x 10-3 (mg/kg/day)-1. 
Page 39 of 94 

6.2 Post-Application Exposure 

A suspension concentrate liquid is proposed for use at a maximum of two applications per year to 

ornamental plantings and trees in residential areas and recreational sites. When determining the 

potential for residential exposure, the Agency considers foliar residues, leaf to skin/hand residue 

transfer, children’s hand-to-mouth residue transfer, and exposure time. In the case of cyflufenamid, 

potential exposure to adults and children would be negligible for the following reasons: 1) Activities 

such as pruning/thinning ornamentals or playing in and around ornamentals when residues may be 

present on the day of the application are unlikely to co-occur; 2) if present, leaf to skin residue transfer 

would be negligible because of the minimal frequency and duration of contact; 3) children young 

enough to exhibit hand-to-mouth behavior would not typically play in ornamental beds or trees. Based 

on the frequency of application and unlikely potential for postapplication exposure, residential 

postapplication risks were not quantitatively assessed; thus, there are no postapplication residential risk 

concerns for this use pattern. 

Based on the Agency's current practices, a quantitative postapplication inhalation exposure 

assessment was not performed for cyflufenamid at this time. However, volatilization of 

pesticides may be a potential source of postapplication inhalation exposure to individuals nearby 

to pesticide applications. The Agency sought expert advice and input on issues related to 

volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act 

Scientific Advisory Panel (SAP) in December 2009. The Agency received the SAP’s final report 

on March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The 

Agency is in the process of evaluating the SAP report and may, as appropriate, develop policies 

and procedures to identify the need for and, subsequently, the way to incorporate postapplication 

inhalation exposure into the Agency's risk assessments. If new policies or procedures are put 

into place, the Agency may revisit the need for a quantitative postapplication inhalation exposure 

assessment for cyflufenamid. 

6.3 Combined Exposure 

Residential postapplication pesticide exposure can occur within a scenario from multiple routes 

of exposure (e.g., dermal, inhalation, and oral). These exposures to pesticides do not occur as 

single, isolated events, but rather as a series of sequential or concurrent events that may overlap 

or be linked in time and space. Based on this, risk estimates resulting from different exposure 

routes may be combined when it is likely that they can occur simultaneously based on the use 

pattern and when the toxicological effects across different routes of exposure are the same. If 

appropriate for an exposure scenario, the recommended routes of exposure for combining 

include dermal, inhalation, and hand-to-mouth. 

For the non-cancer assessment, combined exposures were not necessary to assess for 

cyflufenamid since inhalation exposures for the handlers were the only scenario quantitatively 

assessed. (As discussed in Section 6.1, no dermal hazard was identified.) However, for the 
Page 40 of 94 

cancer assessment, dermal and inhalation exposure were combined in order to estimate the 

LADD and associated risk. 

 

6.4 Spray Drift 

Spray drift is always a potential source of exposure to residents nearby to spraying operations. 

This is particularly the case with aerial application, but, to a lesser extent, could also be a 

potential source of exposure from the ground application method employed for cyflufenamid. 

The Agency has been working with the Spray Drift Task Force, EPA Regional Offices and State 

Lead Agencies for pesticide regulation and other parties to develop the best spray drift 

management practices (see the Agency’s Spray Drift website for more information at 

http://www.epa.gov/opp00001/factsheets/spraydrift.htm). On a chemical by chemical basis, the 

Agency is now requiring interim mitigation measures for aerial applications that must be placed 

on product labels/labeling. The Agency has completed its evaluation of the new database 

submitted by the Spray Drift Task Force, a membership of U.S. pesticide registrants, and is 

developing a policy on how to appropriately apply the data and the AgDRIFT computer model to 

its risk assessments for pesticides applied by air, orchard airblast and ground hydraulic methods. 

After the policy is in place, the Agency may impose further refinements in spray drift 

management practices to reduce off-target drift with specific products with significant risks 

associated with drift. 

 

7.0 Aggregate Exposure/Risk Characterization

Under FQPA, HED must consider and aggregate pesticide exposures and risk from three major 

sources: food, drinking water, and residential exposures. 

7.1 Acute Aggregate Risk 

Acute exposures were not considered because an adverse effect attributable to a single dose was 

not identified. 

7.2 Short- and Intermediate-Term Aggregate Risk 

There is potential short- and intermediate-term exposure to cyflufenamid via the dietary pathway 

(which is considered background exposure) and the residential pathway (which is considered the 

primary pathway). Since no hazard has been identified for the dermal route of residential 

exposure, the aggregate exposure assessment for adults includes dietary (food and drinking 

water) and inhalation exposures. For children, exposure includes only food and drinking water 

since 1) no dermal hazard was identified; 2) ornamentals are the only residential use; and 3) 

dermal, inhalation, and incidental oral exposure to children from treated ornamentals is 

considered to be negligible. As shown in Table 7.2, all aggregate MOEs are greater than 100; 

therefore, aggregate exposure is not of concern. 
Page 41 of 94 

Table 7.2. Short-Term and Intermediate-Term Aggregate Risk Calculations 

Population 

Short- and Intermediate-Term Scenario 

NOAEL 

mg/kg/day LOC1

Max 

Allowable 

Exposure2

(mg/kg/day) 

Average 

Food & 

Water 

Exposure3 

(mg/kg/day) 

Residential 

Exposure4

(mg/kg/day) 

Aggregate MOE 

(food and 

residential)5

Adult Male 5 100 0.05 0.000144 0.0000024 34,000 

Adult Female 5 100 0.05 0.000123 0.0000024 40,000 

Child 5 100 0.05 0.000330 NA 15,000 

1

 This is based on the conventional uncertainty factor of 100x (10x for interspecies extrapolation and 10x for 

intraspecies variation). 

2

 Maximum Allowable Exposure (mg/kg/day) = NOAEL/LOC. 

3

 Dietary exposures for these populations are based on the following population subgroups: Adult Male: U.S. 

population; Adult Female: Females 13-49 years old; and Child: Children 1-2 years old. 

4

 Since no dermal hazard was identified, residential exposure (RE) = oral exposure + inhalation exposure (Table 

6.1.1). REadult = inhalation exposure since no dermal hazard was identified. REchild is not applicable since no 

dermal hazard was identified, and inhalation and incidental oral exposures are negligible from use on ornamentals 

(the only residential use). 5 Aggregate MOE = [NOAEL ÷ (avg food & water exposure + residential exposure)]. 

7.3 Chronic Aggregate Risk 

There is potential chronic exposure via the diet (food and drinking water). Refer to Section 5.4. 

7.4 Cancer Aggregate Risk 

As shown in Table 7.4 below, the aggregate cancer risk (food, water, and residential) is 9.7 x 

10-7. The unit risk for cyflufenamid, Q1

*

, is 6.61 x 10-3 (mg/kg/day)-1. The Q1

*

 is based upon 

male mouse liver combined adenoma and carcinoma tumor rates and is expressed in human 

equivalents. 

Table 7.4 Aggregate Cancer Calculations

Population 

Q1* (mg/kg/day)-1 Negligible Risk 

Level

Chronic Food & 

Water Exposure 

(mg/kg/day) 

Residential 

Exposure 

(LADD)1 

Aggregate 

Cancer Risk 

(food, water and 

residential)2 

U.S. Pop 6.61 x 10-3 generally in the 

range of 10-6

0.000144 2.1 x 10-6 9.7 x 10-7

1

 The residential exposure value used in the aggregate assessment is taken from Table 6.1.2. 2 Aggregate Risk Cancer = Q1* x [Chronic Food & Water Exposure + Residential Exposure (Lifetime Average Daily 

Dose)] 
Page 42 of 94 

8.0 Cumulative Exposure/Risk Characterization

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a 

common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as 

to cyflufenamid and any other substances and cyflufenamid does not appear to produce a toxic 

metabolite produced by other substances. For the purposes of this tolerance action, therefore, 

EPA has not assumed that cyflufenamid has 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 the 

policy statements released by EPA’s Office of Pesticide Programs concerning common 

mechanism determinations and procedures for cumulating effects from substances found to have 

a common mechanism on EPA’s website at http://www.epa.gov/pesticides/cumulative/.

9.0 Occupational Exposure/Risk Characterization

Occupational exposures are expected to occur from the proposed cyflufenamid uses on cucurbits, 

grapes, pome fruit, strawberries, and ornamentals. Short- (1-30 consecutive days) and 

intermediate-term (1-6 consecutive months) dermal and inhalation exposures are expected from 

handler activities while only short- and intermediate-term dermal exposures are expected from 

postapplication activities. 

The short- and intermediate-term dermal risk scenarios were not necessary to assess because no 

hazard was identified for the dermal route of exposure. The short- and intermediate-term 

inhalation risk scenarios were assessed using the NOAEL of 5 mg/kg/day from the prenatal 

developmental study in rabbits. No inhalation absorption data are available; therefore, the 

toxicity by the inhalation route is considered to be equivalent to the estimated toxicity by the oral 

route of exposure. For the cancer assessment, a dermal absorption factor of 12% was utilized in 

the dermal exposure component of the lifetime average daily dose (LADD) while a Q1* of 6.61 x 

10-3 (mg/kg/day)-1 used was to estimate the risk. Also, a body weight of 70 kg was used in all 

exposure estimates because the endpoints were not based on developmental effects. 

9.1 Short-/Intermediate-/Long-Term/Cancer Handler Risk 

Chemical-specific exposure data were not submitted to support the proposed cyflufenamid uses. 

When chemical-specific monitoring data are not available, it is the policy of HED to use data 

from PHED Version 1.1 as presented in the PHED Surrogate Exposure Guide (8/98)1

 or ORETF 

to assess handler exposures for regulatory actions. Additionally, typical HED standard values 

were used for the amount treated per day (ExpoSAC Policy No. 9, 07/05/2000). 

 

1 HED Science Advisory Council for Exposure (ExpoSAC) Policy .007, “Use of Values from PHED Surrogate 

Table and Chemical-Specific Data” HED, OPP, 1/28/99 
Page 43 of 94 

Based upon the proposed cyflufenamid use patterns, HED assessed risks to occupational 

pesticide handlers in the following scenarios: 

• mixing/loading liquid concentrates to support aerial applications, 

• mixing/loading liquid concentrates to support airblast applications, 

• mixing/loading liquid concentrates to support groundboom applications, 

• applying sprays with aircraft, 

• applying sprays with airblast equipment, 

• applying sprays with groundboom equipment, 

• flagging to support aerial spray applications, 

• mixing/loading/applying sprays with backpack sprayers, 

• mixing/loading/applying sprays with low pressure handwand. 

Non-cancer risk estimates for occupational handlers are included in Table 9.1.1. All inhalation 

handler scenarios resulted in MOEs greater than the LOC (MOEs ≥ 100) and, therefore, are not 

of concern. 

Cancer risk estimates for occupational handlers are included in Table 9.1.2. The cancer risks for 

some of the handler scenarios were in the 10-6 range at the baseline level of clothing. However, 

all handler scenarios resulted in cancer risks less than 1 x 10-6 when wearing additional PPE 

(e.g., long-sleeve shirt, long pants, shoes, socks, and chemical resistant gloves) as required by the 

label. 

Table 9.1.1. Summary Of Short-and Intermediate-Term Occupational Handler Exposures And Risks 

Exposure Scenario Crop Grouping 

Application 

Ratea

(lb ai/A) 

Area 

Treated 

Dailyb

(acres/day) 

Baseline 

Inhalationc

Unit 

Exposure 

(μg/lb ai) 

Baseline 

Inhalation 

Dosed

(mg/kg/day) 

Baseline 

Inhalation 

MOEe

(LOC ≥100) 

Mixer/Loader

Mixing/Loading 

Liquid 

Concentrates for 

Aerial 

Applications

Cucurbits 0.011 350 1.2 0.000066 76,000 

Pome fruit 

Grapes 

Strawberries 

0.022 350 1.2 0.00013 38,000 

Mixing/Loading 

Liquids 

Concentrates for 

Groundboom 

Applications 

Cucurbits 0.011 80 1.2 0.000015 330,000 

Strawberries 

Nursery/ornamentals 0.022 80 1.2 0.000030 170,000 

Mixing/Loading 

Liquids 

Concentrates for 

Airblast 

Applications 

Pome fruit 

Grape 

Nursery/ornamentals 

0.022 40 1.2 0.000015 330,000 

Applicator

Applying Sprays Cucurbits 0.011 350 0.068 0.0000037 1,300,000 
Page 44 of 94 

Table 9.1.1. Summary Of Short-and Intermediate-Term Occupational Handler Exposures And Risks 

Exposure Scenario Crop Grouping 

Application 

Ratea

(lb ai/A) 

Area 

Treated 

Dailyb

(acres/day) 

Baseline 

Inhalationc

Unit 

Exposure 

(μg/lb ai) 

Baseline 

Inhalation 

Dosed

(mg/kg/day) 

Baseline 

Inhalation 

MOEe

(LOC ≥100) 

via Aerial 

Equipment 

(enclosed cockpit) 

Pome fruit 

Grapes 

Strawberries 

0.022 350 0.068 0.0000075 670,000 

Applying Sprays 

via Groundboom 

Equipment (open 

cab) 

Cucurbits 0.011 80 0.74 0.0000093 540,000 

Strawberries 

Nursery/ornamentals 0.022 80 0.74 0.000019 270,000 

Applying Sprays 

via Airblast 

Equipment (open 

cab) 

Pome fruit 

Grapes 

Nursery/ornamentals 

0.022 40 4.5 0.000057 88,000 

Flagger 

Flagging for Aerial 

Sprays 

Applications 

Cucurbits 0.011 350 0.35 0.000019 260,000 

Pome fruit 

Grapes, 

Strawberries 

0.022 350 0.35 0.000039 130,000 

Mixer/Loader/Applicator 

Backpack Nursery/Ornamentals 

0.0011f

 40 30 0.000019 260,000 

(lb ai/gal) (gal/day) 

Low Pressure 

Handwand Nursery/Ornamentals 

0.0011 f 40 

30 0.000019 260,000 (lb ai/gal) (gal/day) 

 

a Application rates are the maximum application rates determined from proposed labels for cyflufenamid. 

b Amount handled per day values are HED estimates of acres treated per day based on Exposure SAC SOP #9 “Standard 

Values for Daily Acres Treated in Agriculture,” 

c Baseline Inhalation: no respirator. 

d Inhalation dose = daily unit exposure (μg/lb ai) x application rate (lb ai/A) x area treated (A/day) x mg/1000 μg x 

100% inhalation absorption / body weight (70 kg adult). 

e Inhalation MOE = NOAEL (5.0 mg/kg/day) / inhalation daily dose (mg/kg/day), where LOC = 100 

f Per label instructions and registrant correspondence: 0.0011 lb ai/gal = 3.4 oz conc/20 gal x 0.85 lb ai/gal x 1 gal/128 

oz 
Page 45 of 94 

Table 9.1.2. Summary Of PPE Occupational Handler Exposures and Cancer Risks

Exposure Scenario Crop Grouping 

Application 

Ratea

(lb ai/A) 

Area 

Treated 

Dailyb

(acres/day) 

PPE 

Dermalc

Unit 

Exposure 

(mg/lb ai) 

Baseline 

Inhalationd

Unit 

Exposure 

(μg/lb ai) 

PPE 

Dermal 

Dose e

(mg/kg/day) 

Baseline 

Inhalation 

Dose e

(mg/kg/day) 

Average 

Daily Dose f

(mg/kg/day) 

Exposure 

Days g

(days/yr) 

L

(mg

Mixer/Loader

Mixing/Loading Liquid 

Concentrates for Aerial 

Applications

Cucurbits 0.011 350 0.023 1.2 0.00015 0.000066 0.00022 30 0.0

Pome fruit 

Grapes 

Strawberries 

0.022 350 0.023 1.2 0.00030 0.00013 0.00044 30 0

Mixing/Loading Liquids 

Concentrates for 

Groundboom Applications 

Cucurbits 0.011 80 0.023 1.2 0.000035 0.000015 0.000050 30 0.0

Strawberries 

Nursery/ornamentals 0.022 80 0.023 1.2 0.000069 0.000030 0.00010 30 0.0

Mixing/Loading Liquids 

Concentrates for Airblast 

Applications 

Pome fruit 

Grapes 

Nursery/ornamentals 

0.022 40 0.023 1.2 0.000035 0.000015 0.000050 30 0.0

Applicator 

Applying Sprays via Aerial 

Equipment (enclosed 

cockpit) 

Cucurbits 0.011 350 0.0022 0.068 0.000015 0.0000037 0.000018 30 0.0

Pome fruit 

Grapes 

Strawberries 

0.022 350 0.0022 0.068 0.000029 0.0000075 0.000037 30 0.0

Applying Sprays via 

Groundboom Equipment 

(open cab) 

Cucurbits 0.011 80 0.014 0.74 0.000021 0.0000093 0.000030 30 0.0

Strawberries 

Nursery/ornamentals 0.022 80 0.014 0.74 0.000042 0.000019 0.000061 30 0.0

Applying Sprays via Airblast 

Equipment (open cab) 

Pome fruit 

Grapes 

Nursery/ornamentals 

0.022 40 0.24 4.5 0.00036 0.000057 0.00042 30 0

Flagger 

Flagging for Aerial Sprays 

Applications 

Cucurbits 0.011 350 NA 0.35 NA 0.000019 NA 30 

Pome fruit 

Grapes 

Nursery/ornamentals 

0.022 350 NA 0.35 NA 0.000039 NA 30 

Mixer/Loader/Applicator 
Page 46 of 94 

Table 9.1.2. Summary Of PPE Occupational Handler Exposures and Cancer Risks

Exposure Scenario Crop Grouping 

Application 

Ratea

(lb ai/A) 

Area 

Treated 

Dailyb

(acres/day) 

PPE 

Dermalc

Unit 

Exposure 

(mg/lb ai) 

Baseline 

Inhalationd

Unit 

Exposure 

(μg/lb ai) 

PPE 

Dermal 

Dose e

(mg/kg/day) 

Baseline 

Inhalation 

Dose e

(mg/kg/day) 

Average 

Daily Dose f

(mg/kg/day) 

Exposure 

Days g

(days/yr) 

L

(mg

Backpack Nursery/Ornamentals 

0.0011j 40 

2.5 30 0.00019 0.000019 0.00021 30 0.0

(lb ai/gal) (gal/day) 

Low Pressure Handwand Nursery/Ornamentals 

0.0011 j 40 

0.43 30 0.000033 0.000019 0.000053 30 0.0

(lb ai/gal) (gal/day) (lb ai/gal) (gal/day) 

a Application rates are the maximum application rates determined from proposed labels for cyflufenamid. b Amount handled per day values are HED estimates of acres treated per day based on ExpoSAC SOP No.9 “Standard Values for Daily Acres Treatc PPE Dermal: long pants, long sleeves, and chemical resistant gloves d Baseline Inhalation: no respirator. e Dose = daily unit exposure (μg/lb ai) x application rate (lb ai/A) x area treated (A/day) x mg/1000 μg (as needed) x 100% inhalation absorption or 

weight (70 kg adult). 

f Average daily dose (ADD) (mg/kg/day) = dermal dose (mg/kg/day) + inhalation dose (mg/kg/day) g Exposure days: HED default for number of worker days h LADD (Lifetime average daily dose) (mg/kg/day) = ADD x (30 days/yr x 35 yr) / (365 days/yr x 70 yr) i Cancer risk = LADD (mg/kg/day) x Q* of 6.6 x 10-3 (mg/kg/day)-1 

j Per label instructions and registrant correspondence: 0.0011 lb ai/gal = 3.4 oz conc/20 gal x 0.85 lb ai/gal x 1 gal/128 oz 
Page 47 of 94 

9.2 Short-/Intermediate-/Long-Term/Cancer Post-Application Risk 

There is a possibility for agricultural workers to have postapplication dermal exposure to 

cyflufenamid following its proposed new uses. However, non-cancer occupational 

postapplication dermal exposure and risks were not assessed because, as previously discussed in 

Section 2.0, no hazard was identified for the dermal route of exposure. 

Because cyflufenamid is “likely to be carcinogenic to humans”, cancer risks from 

postapplication activities were assessed. Chemical-specific data relevant to postapplication 

exposure (i.e., dislodgeable foliar residue (DFR) data) for the new cyflufenamid proposed uses 

were not submitted. Therefore, postapplication exposure estimates were calculated using the 

standard HED ExpoSAC assumptions (i.e., default DFR input parameters and exposure duration) 

and HED transfer coefficients (SOP No. 3.1). 

HED uses a concept known as the transfer coefficient (TC) to numerically represent the 

postapplication exposures one would receive (generally presented as cm2

/hour). A TC is a 

measure of the residue transferred from a treated surface to a person who is doing a task or 

activity in a treated area. These values are the ratio of an exposure for a given task or activity to 

the amount of pesticide residue on treated surfaces available for transfer. HED has developed a 

series of standard TCs that are unique for a variety of job tasks or activities that are used in lieu 

of chemical- and scenario-specific data. HED used Policy 3.1 Science Advisory Council for 

Exposure Policy Regarding Agricultural Transfer Coefficients to estimate TCs for the various 

tasks that postapplication workers might perform on each crop grouping. 

In the absence of chemical-specific DFR data, HED assumes that 20% of the initial application is 

available for transfer on day 0 (i.e., 12 hours after application) and that the residue dissipates at a 

rate of 10% per day. Furthermore, HED also assumes an 8 hour workday for postapplication 

workers. Average daily doses (ADD) were calculated on each day after application. LADDs 

and cancer risks were calculated for each postapplication activity. 

Table 9.2 presents the results of the occupational postapplication cancer risk assessment when 

HED default assumptions are used. Using surrogate data, the cancer risks from agricultural 

postapplication activities range from 7.4 x 10-8 to 4.1 x 10-6 on day 0 (12 hours following 

application). Although cyflufenamid specific DFR studies on grapes and ornamentals could be 

used to refine and mitigate the cancer risks for these scenarios, this assessment incorporates 

conservative parameters such as maximum application rates and assuming workers are exposed 

to “Day 0” cyflufenamid residue levels for 250 days/year even though only two applications per 

ornamental type per year can be made with a retreatment interval of 21 days. 
Page 48 of 94 

Table 9.2. Summary of Occupational Postapplication Cancer Risks for Proposed Cyflufenamid Uses* 

Crop Appl. 

Rate 

(lb ai/A) 

Fraction of 

ai Retained 

on Foliage1

Transfer 

Coefficient 

(cm2/hr)2

Dislodgeable 

Foliar 

Residue3

(μg/cm2) 

Average 

Daily Dose4

(mg/kg/day) 

(

Pome fruit (fruit trees) 0.022 20% High/full: harvesting (1,500) 0.049 0.0010 

High/full: thinning (3,000) 0.049 0.0020 

Strawberries 0.022 20% 

Low/full: irrigation, mulching, scouting, hand weeding 

(400) 0.049 0.00027 

Low/full: hand harvest, hand pruning, pinching, training (1,500) 0.049 0.0010 

Grapes 0.022 20% 

High/full: hand weeding (500) 0.049 0.00034 

High/full: scouting (1,000) 0.049 0.00068 High/full: hand harvest, hand pruning, thinning (5,000) 0.049 0.0034 High/full: girdling, cane turning, cane tying (10,000) 0.026 0.0068 

Cucurbits 0.011 20% Low/full: irrigation, scouting, hand weeding (1,500) 0.025 0.00051 

Low/full: hand harvest, hand pruning, thinning (2,500) 0.025 0.00085 

Ornamentals 0.022 20% High/full: pruning, tying (110) 0.049 0.00062 

High/full: moving potted plants (400) 0.049 0.0023 High/full: cut flowers (2,700) 0.049 0.0018 

* Unless otherwise noted, all exposures and risks are estimated on day 0 after application 1 HED default 2 Transfer coefficients are taken from the HED ExpoSAC SOP 3.1 (August 2000) 3 Dislodgeable Foliar Residue Postapplication day (μg/cm2) = Application rate (lb ai/A) x Fraction of ai Retained on the Foliage x (1- Fraction of Residue that Dissipates Daily) p

x 2.47E-8 A/cm2

4 Average Daily Dose = [Dislodgeable Foliar Residue x 0.001 mg/μg x Dermal Transfer Coefficient (cm2/hr) x Exposure Time (8 hr/day) x Dermal absorption (12%)]/Bo5 LADD = ADD x (30 or 250 days/yr x 35 yr) / (365 days/yr x 70 yr); note: it was assumed that exposure frequency is 30 days/yr for all scenarios excep

days/yr was used

6 Cancer risk = LADD (mg/kg/day) x Q* (mg/kg/day)-1
Page 49 of 94 

Based on the Agency's current practices, a quantitative postapplication inhalation exposure 

assessment was not performed for cyflufenamid at this time. However, volatilization of 

pesticides may be a potential source of postapplication inhalation exposure to individuals nearby 

to pesticide applications. The Agency sought expert advice and input on issues related to 

volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act 

Scientific Advisory Panel (SAP) in December 2009. The Agency received the SAP’s final report 

on March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html) and is 

in the process of evaluating the SAP report. The Agency may, as appropriate, develop policies 

and procedures to identify the need for and, subsequently, the way to incorporate postapplication 

inhalation exposure into the Agency's risk assessments. If new policies or procedures are put 

into place, the Agency may revisit the need for a quantitative postapplication inhalation exposure 

assessment for cyflufenamid. 

Restricted Entry Interval: For all activities and crops, the REI of 12 hours on the proposed 

label is adequate to protect workers. The REI is based on the acute toxicity of cyflufenamid 

technical material. Cyflufenamid is classified in acute toxicity category III/IV for acute dermal 

toxicity and category IV/III for primary eye irritation and primary skin irritation. It is not a 

dermal sensitizer. Under the WPS for Agricultural Pesticides, active ingredients classified as 

acute toxicity categories III or IV for these routes are assigned a 12-hour REI. Therefore, the 

REI of 12 hours for all activities and crops is appropriate and meets the requirements of the 

WPS. 

10.0 Incidents 

No information is available from use in the U.S. since this is the first registration in the U.S. 

11.0 Environmental Justice Considerations 

Potential areas of environmental justice concerns, to the extent possible, were considered in this 

human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal Actions 

to Address Environmental Justice in Minority Populations and Low-Income Populations," 

http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf). 

As a part of every pesticide risk assessment, OPP considers a large variety of consumer 

subgroups according to well-established procedures. In line with OPP policy, HED estimates 

risks to population subgroups from pesticide exposures that are based on patterns of that 

subgroup’s food and water consumption, and activities in and around the home that involve 

pesticide use in a residential setting. Extensive data on food consumption patterns are compiled 

by the USDA under the Continuing Survey of Food Intake by Individuals (CSFII) and are used 

in pesticide risk assessments for all registered food uses of a pesticide. These data are analyzed 

and categorized by subgroups based on age, season of the year, ethnic group, and region of the 

country. Additionally, OPP is able to assess dietary exposure to smaller, specialized subgroups 

and exposure assessments are performed when conditions or circumstances warrant. Whenever 

appropriate, non-dietary exposures based on home use of pesticide products and associated risks 

for adult applicators and for toddlers, youths, and adults entering or playing on treated areas 
Page 50 of 94 

postapplication are evaluated. Further considerations are currently in development as OPP has 

committed resources and expertise to the development of specialized software and models that 

consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary 

patterns among specific subgroups. 

12.0 References 

Kramer, G.F., Ph.D., 5/18/2010, DP#377139, Cyflufenamid. Report of the Residues of Concern 

Knowledge-based Subcommittee (ROCKS). 

Brunsman, L.L., 4/8/2010, DP#363403, TXR#0055318, Cyflufenamid Qualitative Risk 

Assessment Based on CD Rat and CD-1 Mouse Dietary Studies. 

Negussie, M., 7/23/2010, DP#364556, Cyflufenamid. Section 3 Registration Request for Uses on 

Cucurbit Vegetables (Crop Group 9), Pome Fruit (Crop Group 11), Small Fruit Vine Climbing 

Except Fuzzy Kiwifruit (Subgroup 13-07F), and Low Growing Berry (Subgroup 13-07G), except 

Cranberry. Summary of Analytical Chemistry and Residue Data. 

Negussie, M., 7/20/2010, DP#364559, Cyflufenamid: Chronic Aggregate Dietary (Food and 

Drinking Water) Exposure and Risk Assessments for the First Food Uses in Support of a Section 

3 Registration Action on Cucurbit Vegetables (Crop Group 9), Pome Fruit (Crop Group 11), 

Small Fruit Vine Climbing Except Fuzzy Kiwifruit (Subgroup 13-07F), and Low Growing Berry 

(Subgroup 13-07G), except Cranberry. 

Walls, C., Ph.D., 5/24/10, DP#364557, CYFLUFENAMID: Occupational and Residential 

Exposure/Risk Assessment for Use on Cucurbit Vegetables, Pome Fruit, Small Fruit Vine, Low 

Growing Berry, and Ornamentals. 

Bohaty, R.F.H., Ph.D., 4/15/2010, DP#360795, The Drinking Water Degradation Products 

Identification Memorandum for Cyflufenamid. 

 

Bohaty, R.F.H., Ph.D., 5/3/2010, DP#362954, Drinking Water Assessment for the Registration of 

Cyflufenamid (MILTREX® 10 SC FUNGICIDE) Uses on: Cucurbit Vegetables (Crop Subgroup 

9), Low Growing Berries (Crop Subgroup 13-07G), Outdoor Landscape and Nursery 

Ornamentals, Pome Fruit (Crop Group 11), and Small Fruit Vines Climbing except Fuzzy 

Kiwifruit (Crop Subgroup 13-07F). 
Page 51 of 94 

Appendix A. Toxicology Profile and Executive Summaries 

A.1 Toxicology Data Requirements

The requirements (40 CFR 158.340) for food uses for cyflufenamid are in Table 1. Use of the new guideline 

numbers does not imply that the new (1998) guideline protocols were used. A description of the outstanding study 

is in Appendix E. 

Table 1.: Toxicology Data Requirements 

Test Technical

Required Satisfied

870.1100 Acute Oral Toxicity ....................................................... 

870.1200 Acute Dermal Toxicity .................................................. 

870.1300 Acute Inhalation Toxicity .............................................. 

870.2400 Primary Eye Irritation .................................................... 

870.2500 Primary Dermal Irritation .............................................. 

870.2600 Dermal Sensitization...................................................... 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

870.3100 Oral Subchronic (rodent) ............................................... 

870.3150 Oral Subchronic (nonrodent) ......................................... 

870.3200 21-Day Dermal .............................................................. 

870.3250 90-Day Dermal .............................................................. 

870.3465 90-Day Inhalation .......................................................... 

yes 

yes 

yes 

cr 

cr 

yes 

yes 

yes 

no 

no 

870.3700a Developmental Toxicity (rodent) ................................... 

870.3700b Developmental Toxicity (nonrodent)............................. 

870.3800 Reproduction ................................................................. 

yes 

yes 

yes 

yes 

yes 

yes 

870.4100a Chronic Toxicity (rodent) .............................................. 

870.4100b Chronic Toxicity (nonrodent) ........................................ 

870.4200a Oncogenicity (rat) .......................................................... 

870.4200b Oncogenicity (mouse) .................................................... 

870.4300 Chronic/Oncogenicity .................................................... 

na 

yes 

na 

yes 

yes 

- 

yes 

- 

yes 

yes 

870.5100 Mutagenicity—Gene Mutation - bacterial ..................... 

870.5300 Mutagenicity—Gene Mutation - mammalian ................ 

870.5375 Mutagenicity—Structural Chromosomal Aberrations ... 

870.5395 Mutagenicity—Other Genotoxic Effects ....................... 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

yes 

870.6100a Acute Delayed Neurotox. (hen) ..................................... 

870.6100b 90-Day Neurotoxicity (hen) ........................................... 

870.6200a Acute Neurotox. Screening Battery (rat) ....................... 

870.6200b 90-Day Neuro. Screening Battery (rat) .......................... 

870.6300 Develop. Neuro .............................................................. 

no 

no 

yes 

yes 

cr 

- 

- 

no+

yes 

no 

870.7485 General Metabolism ...................................................... 

870.7600 Dermal Penetration ........................................................ 

870.7800 Immunotoxicity ............................................................. 

yes 

cr 

yes 

yes 

no 

yes 

+Waiver was denied 
Page 52 of 94 

A.2 Toxicity Profiles

Table A.2.1 Acute Toxicity Profile – Cyflufenamid, TGAI 

Guideline No. Study Type MRID(s) Results Toxicity Category 

870.1100 Acute oral [rat] 47620418 LD50 > 5000 mg/kg IV 

870.1200 Acute dermal [rat] 47620419 LD50 > 2000 mg/kg III 

870.1300 Acute inhalation [rat] 47620420 LC50 > 4.76 mg/L IV 

870.2400 Acute eye irritation [rabbit] 47620421 minimally irritating III 

870.2500 Acute dermal irritation [rabbit] 47620422 Non-irritating IV 

870.2600 Skin sensitization [guinea pig] 47620423 Negative NA 

Table A.2.2 Acute Toxicity Profile – Cyflufenamid Metabolites 

Guideline No. 

Acute Oral Toxicity in Rats, 

Metabolite: 

MRID(s) Results Toxicity Category 

870.1100 149-F 47620609 LD50 = 2828 mg/kg III 

870.1100 149-F1 47620610 LD50 = 394 mg/kg II 

870.1100 149-F6 47620611 LD50 = 686 mg/kg III 

870.1100 149-F11 47620612 LD50 = 1162 mg/kg III 

870.1100 149-(E)-FB 47620613 LD50 > 5000 mg/kg IV 
Page 53 of 94 

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile

Guideline 

No. 

Study Type MRID No. (year)/ 

Classification /Doses

Results

870.3100 90-Day oral 

toxicity (rat) 

47638204 (1997) 

Acceptable/guideline 

0, 50, 300, 1800 or 10800 

ppm 

M: 0, 3.3, 20.1, 117.4, 

673.3 mg/kg/day 

F: 0, 4.1, 24.7, 143.9, 

782.6 mg/kg/day 

NOAEL = 20.1 mg/kg/day ♂, 24.7 mg/kg/day 

♀

LOAEL = 117.4 mg/kg/day ♂, 143.9 

mg/kg/day ♀, based on decreased body weight 

gain, centrilobular hepatocellular hypertrophy 

and increased relative organ weights (liver, 

kidney, thyroid) 

870.3100 90-Day oral 

toxicity (mouse) 

47638202 (1998) 

Acceptable/guideline 

0, 100, 400, 1600 or 7000 

ppm 

M: 0, 14.0, 50.7, 218.1 or 

808.0 mg/kg/day 

F: 0, 17.6, 70.8, 295.1 or 

940.2 mg/kg/day 

NOAEL = 218.1 mg/kg/day ♂, 295.1 

mg/kg/day ♀

LOAEL = 808.0 mg/kg/day ♂, 940.2 

mg/kg/day ♀ based on hepatocellular 

hypertrophy, increased liver weight. 

870.3150 90-Day oral 

toxicity (dog) 

47620504 (1999) 

Acceptable/guideline 

0, 150, 500, 1500 ppm 

M: 0, 6.5, 23.2, 76.2 

mg/kg/day 

F: 0, 7.5, 24.4, 70.5 

mg/kg/day 

NOAEL = 23.2 mg/kg/day ♂, 24.4 mg/kg/day 

♀

LOAEL = 76.2 mg/kg/day ♂, 70.5 mg/kg/day 

♀ based on decreased body weight gain and 

hepatomegaly accompanied by vacuolated 

hepatocytes and fat deposition 

870.3200 21/28-Day dermal 

toxicity (rat) 

47620428 (2000) 

Acceptable/guideline 

M/F: 0, 100, 300, 1000 

mg/kg/day 

NOAEL = 1000 mg/kg/day. 

LOAEL > 1000 mg/kg/day. 

870.3700a Prenatal 

developmental in 

(rat) 

47620506 (2000) 

Acceptable/guideline 

F: 0, 100, 300, 1000 

mg/kg/day 

Maternal NOAEL = 300 mg/kg/day 

LOAEL = 1000 mg/kg/day based on increased 

liver weight and brown staining of coat in 

anterior region, piloerection and ungroomed 

appearance, indicators of deteriorating health 

Developmental NOAEL = 1000 mg/kg/day. 

LOAEL > 1000 mg/kg/day. 

870.3700b Prenatal 

developmental in 

(rabbit) 

47620508 (2000) 

Acceptable/guideline 

F: 0, 10, 60, 300 

mg/kg/day 

47620509 (2001) 

Acceptable/non-guideline 

F: 0, 5, 10 mg/kg/day 

Maternal NOAEL = 5 mg/kg/day ( from 

MRID 47620509). 

LOAEL = 10 mg/kg/day based on decreased 

body weight gain and food consumption 

Developmental NOAEL = 10 mg/kg/day 

LOAEL = 60 mg/kg/day based on decreased 

fetal weight, and incomplete ossification of 

cervical 

vertebrae/epiphyses/metacarpals/phalanges. 
Page 54 of 94 

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile

Guideline 

No. 

Study Type MRID No. (year)/ 

Classification /Doses

Results

870.3800 Reproduction and 

fertility effects 

(rat) 

47620514 (2000) 

Acceptable/guideline 

0, 80, 250, 800 ppm 

M0: 0, 5.8, 18.0, 57.4 

mg/kg/day 

F0: 0, 6.5, 19.9, 66.2 

mg/kg/day 

M1: 0, 7.4, 23.0, 75.2 

mg/kg/day 

F1: 0, 7.8, 24.1, 78.2 

mg/kg/day 

Parental/Systemic NOAEL = 18 mg/kg/day ♂, 

19.9 mg/kg/day ♀. 

LOAEL = 57.4 mg/kg/day ♂, 66.2 mg/kg/day 

♀ based on increased liver and thyroid weights. 

Reproductive NOAEL = 57.4 mg/kg/day ♂, 

66.2 mg/kg/day ♀

LOAEL > HDT. 

Offspring NOAEL = 18 mg/kg/day ♂, 19.9 

mg/kg/day ♀. 

LOAEL = 57.4 mg/kg/day ♂, 66.2 mg/kg/day 

♀ based on reduced body weight gain in both 

F1 and F2 offspring. 

870.4100b Chronic toxicity 

(dog) 

47620505 (2000) 

Acceptable/guideline 

0, 30, 120, 480 ppm 

M: 0, 1.04, 4.14, 17.29 

mg/kg/day 

F: 0, 1.08, 4.41, 17.32 

mg/kg/day 

NOAEL = 17.29 mg/kg/day ♂, 17.32 

mg/kg/day ♀. 

LOAEL > 17.32 mg/kg/day 

870.4200 Carcinogenicity 

(mouse) 

47638206 (2000) 

Acceptable/guideline 

0, 60, 500, 4000/2000 

ppm 

M: 0, 7, 63, 325 

mg/kg/day 

F: 0, 9, 76, 404 mg/kg/day 

NOAEL 63 mg/kg/day ♂, 76 mg/kg/day ♀

LOAEL = 325 mg/kg/day ♂, 404 mg/kg/day ♀

based on premature death (within first 20 

weeks of treatment) attributed to fatty changes 

in liver, heart (vacuolization within myocytes) 

and kidney (vacuolization in cortical tubular 

epithelium). 

Hepatocellular adenomas were seen in 17/50 

males in the high-dose group (vs. 6/50 

control males) 

870.4300 Carcinogenicity 

(rat) 

47620511 (2001) 

Acceptable/guideline 

0, 100, 500, 2000 ♀/5000 

♂ ppm 

M: 0, 4.4, 22, 229 

mg/kg/day 

F: 0, 5.5, 28, 115 

mg/kg/day 

NOAEL = 4.4 mg/kg/day ♂, 5.5 mg/kg/day ♀

LOAEL = 22 mg/kg/day ♂, 28 mg/kg/day ♀

based on decreased body weight gain; increased 

thyroid/parathyroid weight, increased liver 

weight and centrilobular hepatocytic 

hypertrophy in females; hyaline droplets and 

pigmented cortical tubules and cortical 

hemorrhagic degeneration of adrenals in males. 

Thyroid follicular cell tumors were observed 

in males of the high-dose group. 

870.5100 Bacterial Reverse 

Mutation 

47620515 (2000) NF-149, TGAI has no reverse mutagenic 

potential at the limit dose under the 

experimental conditions. 
Page 55 of 94 

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile

Guideline 

No. 

Study Type MRID No. (year)/ 

Classification /Doses

Results

870.5100 Bacterial Reverse 

Mutation 

47620618 (2000) 149-(E)-FB (NF-149 isomer) has no reverse 

mutagenic potential at the limit dose under the 

experimental conditions. 

870.5300 In vitro 

Mammalian Gene 

Mutation 

47620516 (1997) No statistically significant increases in mutant 

frequency were observed following treatment 

with NF-149 (≤ 200 μg/mL). 

870.5375 In vitro 

Mammalian 

Chromosome 

Aberration 

47620517 (2000) NF-149 (≤ 250 μg/mL ±S9 for 3 hours; ≤ 31.3 

μg/mL –S9 for 21 hours) showed no evidence 

of clastogenic or polyploidy-inducing activity 

in this cytogenic test system. 

870.5395 Mammalian 

Erythrocyte 

Micronucleus 

47620518 (2000) NF-149 (≤ 2000 mg/kg) did not show any 

evidence of causing chromosome damage or 

bone marrow cell toxicity when administered 

orally by intragastric gavage under the 

experimental conditions described. 

870.5550 Unscheduled DNA 

Synthesis in 

Mammalian 

Cultured Cells 

47620519 (1997) NF-149 (≤ 2000 mg/kg) did not show any 

evidence of causing DNA damage in rat 

hepatocytes. 

870.6200a Acute neurotoxicity 

screening battery 

47620501 (2008) 

Waiver request 

The requested waiver was denied. 

870.6200b Subchronic 

neurotoxicity 

screening battery 

47638205 (2001) 

Acceptable/guideline 

0, 200, 1000, 5000 ppm 

M: 0, 18, 88, 453 

mg/kg/day 

F: 0, 21, 98, 572 

mg/kg/day 

NOAEL = 88 mg/kg/day ♂, 98 mg/kg/day ♀

LOAEL = 453 mg/kg/day ♂, 572 mg/kg/day ♀

based on decreased body weight gain and food 

efficiency in both sexes. 
Page 56 of 94 

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile

Guideline 

No. 

Study Type MRID No. (year)/ 

Classification /Doses

Results

870.7485 Metabolism and 

pharmacokinetics 

(rat) 

47620520 (2000) ADME after administration of [fluorinated 

phenyl-U-14C]NF-149, 10 mg/kg or 200 mg/kg. 

Greater that 85% of the administered dose 

(AD) was excreted within 48 hours. Urinary 

excretion was greater in males than females 

after a single dose and absorption was greater 

in females. The majority of radioactivity was 

recovered in the feces and bile. The 

elimination half-lives were in the range of 14 – 

34 hours for plasma and greater than 70 hours 

for blood. Tissue half-lives were generally less 

than twice those of plasma (after single dose). 

The highest tissue concentrations of 

radioactivity after 168 hrs were detected in the 

liver, kidney and fat. Overall tissue 

accumulation was low with < 1% AD retained 

at 168 hr post-single dose. Excepting 149-F1, 

primarily a urinary metabolite (15.4% AD), 

major metabolites were recovered, primarily in 

the feces, in the following amounts in males: 

149-F-3-OH-4-OH-B, 10.9%; 149-F, 4.4%; 

NF-149 (parent), 3.7%; 149-F-4-OH-B, 1.9%; 

149-F-3-OH-B, 1.6%. The major metabolites 

were recovered primarily in the feces in the 

following amounts in females: 149-F-3-OH-4-

OH-B, 27.3%; 149-F-4-OH-B, 6.2%; NF-149 

(parent), 4.6%; 149-F, 2.8%; 149-F1 was 

recovered as 9.9% AD in the urine of females. 

870.7485 Metabolism and 

pharmacokinetics 

(rat) 

47620521 (2002) ADME of [cyclopropyl-2, 3-14C]NF-149, 10 

mg/kg. Greater that 85% AD was excreted 

within 72 hours. A higher proportion of the 

dose was excreted in the urine of male rats 

(37.7 % AD vs. 19.7% AD in females) while 

fecal excretion was higher in females (69.5% 

AD vs. 56.9% in males). The highest tissue 

concentrations of radioactivity after 168 hrs 

were detected (in order of greatest 

concentration) in fat, thyroid, epididymis, 

adrenals, liver, ovary, pancreas, prostate and 

skin with hair. The major metabolite detected 

in urine of both males and females was CPCAGly. The major metabolites in feces were 149-

F-3-OH-4-OH-B (33.4% AD ♂, 41.4% AD ♀), 

149-F-3-OH-B (3.2% AD ♂, 4.5% AD ♀), 

149-F-4-OH-B (1.6% AD ♂, 9.8% AD ♀). 
Page 57 of 94 

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile

Guideline 

No. 

Study Type MRID No. (year)/ 

Classification /Doses

Results

870.7485 Metabolism and 

pharmacokinetics 

(rat) 

47620522 (2001) Pharmacokinetics of [cyclopropyl-2, 3-14C]NF149, 10 mg/kg. The following pharmacokinetic 

parameters were observed in plasma: Cmax = 

1.3 μg/g ♂, 0.9 μg/g ♀ at 2 hours (Tmax); t1⁄2= 

6.5 hr ♂, 7.9 hr ♀; AUC = 12.3 μg·h/g ♂, 10 

μg·h/g ♀. The following pharmacokinetic 

parameters were observed in blood: Cmax = 

0.31 μg/g ♂, 0.35 μg/g ♀ at 2 hours (Tmax); 

t1⁄2= 25.3 hr ♂, 9.0 hr ♀; AUC = 9.88 μg·h/g ♂, 

4.64 μg·h/g ♀. Absorption and elimination 

rates were rapid for male and female rats and 

similar to absorption and elimination rates 

observed with [fluorinated phenyl-U-14C]NF149. 

870.7800 Immunotoxicity 

(mouse) 47620523 (2008) 

Acceptable/guideline 

0, 400, 1600, 7000 ppm 

M: 0, 50, 298, 1916 

mg/kg/day 

F: 0, 63, 388, 2542 

mg/kg/day 

NOAEL = 1916 mg/kg/day ♂, 2542 mg/kg/day 

♀. 

LOAEL > 1916 mg/kg/day ♂, 2542 mg/kg/day 

♀. 

There were no statistically significant changes 

in either the number of PFC/106

 splenocytes or 

PFC/spleen for any treatment group compared 

to control. 

870.7800 Immunotoxicity 

(rat) 47620524 (2008) 

Acceptable/guideline 

0, 300, 1800, 10800 ppm 

M: 0, 24, 150, 942 

mg/kg/day 

F: 0, 25, 150, 927 

mg/kg/day 

NOAEL = 942 mg/kg/day, males; 150 

mg/kg/day, females. 

LOAEL > 942 mg/kg/day, males; LOAEL = 

927 mg/kg/day, based on depression of the 

corpus mucosa and a decrease in spleen cells 

and PFC/spleen in females. 
Page 58 of 94 

A.3 Hazard Identification and Endpoint Selection

A.3.1 Acute Reference Dose (aRfD) - Females age 13-49 and the General Population

An acute reference dose was not defined; no effects attributable to a single dose were identified 

in the toxicology database. 

A.3.2 Chronic Reference Dose (cRfD) 

Study Selected: Combined Chronic Toxicity/ Carcinogenicity Study in Rats 

MRID No.: 47620511 

Executive Summary: See Appendix A, Guideline 870.4300 

Dose and Endpoint for Risk Assessment: NOAEL = 4.4 mg/kg/day based on decreased body 

weight gain and liver effects seen at LOAEL = 22 mg/kg/day. 

Comments about Study/Endpoint/Uncertainty Factors: This study is the most appropriate 

exposure scenario based on duration. The critical effect is liver toxicity which is seen across all 

species tested via oral administration. When LOAELs are compared among rat, dog and mouse 

chronic feeding studies, the rat is the most sensitive species. 

A.3.3 Incidental Oral Exposure (Short- and Intermediate-Term) 

Study Selected: Prenatal Developmental Study in Rabbits 

MRID No.: 47620508, 47620509 

Executive Summary: See Appendix A, Guideline 870.3700 

Dose and Endpoint for Risk Assessment: Maternal NOAEL = 5 mg/kg/day based on 

decreased body weight, body weight gain and food consumption seen at LOAEL = 10 

mg/kg/day. 

Comments about Study/Endpoint/Uncertainty Factors: The duration of dosing, gestation 

day (GD) 6-28, is appropriate for the short-term exposure scenario and protective for 

intermediate-term exposure (see discussion below, A3.5). A maternal LOAEL of 10 mg/kg/day, 

but no NOAEL, was established in the guideline study. A subsequent bridging study was 

conducted with 0, 5 or 10 mg/kg/day. No adverse findings were observed in either treatment 

group. Therefore, a NOAEL of 5 mg/kg/day can be defined. Though an acceptable/guideline 

multigeneration study is available to represent the population at risk (infants and young 

children), the prenatal developmental study chosen to protect for inhalation exposure (adult) is 

more protective and, therefore, applied to short- and intermediate-term incidental oral (child) 

also.

A.3.4 Dermal Exposure (Short-, Intermediate- and Long-Term) 

No hazard was identified for the dermal route of exposure. Cyflufenamid was applied to shaved, 

intact skin of 5 rats/sex/dose at dose levels up to and including the limit dose for 7 hours/day, 7 

days/week for 4 weeks. No adverse treatment-related effects were observed on mortality, 

clinical signs of toxicity dermal irritation, body weight, body weight gain, food consumption, 
Page 59 of 94 

food efficiency, ophthalmoscopic exams, hematology, clinical chemistry, urinalysis, absolute or 

relative organ weights, and gross or microscopic pathology in either sex at the limit dose. 

A.3.5 Inhalation Exposure 

Study Selected: Prenatal Developmental Study in Rabbits 

MRID No.: 47620508, 47620509 

Executive Summary: See Appendix A, Guideline 870.3700 

Dose and Endpoint for Risk Assessment: Maternal NOAEL = 5 mg/kg/day based on 

decreased body weight, body weight gain and food consumption seen at LOAEL = 10 

mg/kg/day. 

(Short-Term) 

Comments about Study/Endpoint/Uncertainty Factors: The duration of dosing, GD 6-28, is 

appropriate for this exposure scenario. A maternal LOAEL of 10 mg/kg/day, but no NOAEL 

was established in the guideline study. A subsequent bridging study was conducted with 0, 5 or 

10 mg/kg/day. No adverse findings were observed in either treatment group. Therefore, a 

NOAEL of 5 mg/kg/day can be defined. Complete absorption is assumed.

(Intermediate-Term) 

Comments about Study/Endpoint/Uncertainty Factors: A maternal LOAEL of 10 

mg/kg/day, but no NOAEL, was established in the guideline study. A subsequent bridging study 

was conducted with 0, 5 or 10 mg/kg/day. No adverse findings were observed in either treatment 

group. Therefore, a NOAEL of 5 mg/kg/day can be defined. Complete absorption is assumed. 

Though duration of dosing, GD 6-28, is less than appropriate for this exposure scenario and an 

acceptable/guideline multigeneration study is available to represent the duration of exposure, the 

prenatal developmental study chosen to protect short-term inhalation is more protective and, 

therefore, chosen for intermediate-term inhalation exposure also. 

A.4 Executive Summaries 

A.4.1 Subchronic Toxicity

 870.3100 90-Day Oral Toxicity – Rat 

In a subchronic oral toxicity study (MRID 47638204), cyflufenamid (NF-149; 96.4% a.i.; Lot 

No. 31-6415-A0) was administered in the diet to Crj:CD (SD) rats (10/sex/dose) at doses of 0, 

50, 300, 1800, or 10,800 ppm (equivalent to 0/0, 3.3/4.1, 20.1/24.7, 117.4/143.9, and 673.3/782.6 

mg/kg/day for males/females) for 13 weeks. 

No treatment-related effect was observed on mortality, ophthalmoscopic examination, or 

hematology. 
Page 60 of 94 

General systemic toxicity was evident in 1800 ppm females. Decreased body weights were 

observed during Days 56-84 (decr 8-10%, p < 0.05). Decreased (p<0.01) body weight gain was 

noted on Day 1, as well as decreased overall (Days 0-91) body weight gain was noted (decr 13%, 

NS). Decreased absolute and relative (decr 25-27%, p < 0.01) food consumption was also 

observed on Day 1. The large initial decrease in food consumption on Day 1 followed by much 

smaller decreases afterwards suggests a palatability issue. Increased (NS) incidences of the 

following macroscopic signs were observed (# affected/10 treated vs. 0/10 controls): decreased 

intraperitoneal adipose tissue in the males (3) and females (2); and decreased subcutaneous 

adipose tissue in the females (1). 

The kidney was a target organ. At 1800 ppm and above, increased plasma blood urea nitrogen 

was observed in the females (incr 69-97%, p < 0.05). Increased (p<0.05) concentrations of 

ketone bodies were noted in the urine of the females. Increased right and left relative kidney 

weights were observed in the males (incr 8-30%, p < 0.05) and females (incr 14-29%, p < 0.05). 

Slight hyaline droplets in renal tubular epithelium were observed in all treated males and 

increased phosphorous was noted in both sexes (incr 33-48%, p < 0.05). 

Additionally at 10,800 ppm, increased plasma blood urea nitrogen was observed in the males 

(incr 38%, p < 0.05). Right and left absolute and relative kidney weights in the 10,800 ppm 

males were increased compared to control (incr 9-30%, p < 0.05). Increased incidence of slight 

renal tubular vacuolization was noted in the 10,800 ppm females (6/10 treated vs. 0/10 controls, 

p < 0.01). Increased serum phosphorous was noted in high-dose males (incr 33%, p < 0.05) and 

females (incr 48%, p < 0.05). 

At 10,800 ppm, there was additional evidence of general toxicity. An increased frequency of 

slight abdominal distention was noted in the females. An increased frequency of urine soiling 

around the urethra was observed in the females (predominantly slight severity) and males 

(slight). Decreased body weights were observed throughout treatment in both sexes. In both 

sexes, body weight losses were noted on Day 1; weekly cumulative interval body weight gains 

were decreased throughout treatment in both sexes. Decreased overall (Days 0-91) body weight 

gains were noted in both sexes. Absolute and relative food consumption were markedly 

decreased on Day 1 in both sexes. After Day 1, decreases (p < 0.05) in absolute food 

consumption were noted on Days 7, 28, 35, 42, and 63 in males and on Days 7 through 21 in 

females. Relative food consumption (g/kg bw/day) was decreased (p < 0.01) in both sexes on 

Day 7. The large initial decrease in food consumption on Day 1 followed by much smaller 

decreases afterwards suggests a palatability issue. On Day 1, decreased (p <0.01) food 

efficiency was also noted in both sexes. Increased (p<0.05) incidences of the following 

macroscopic signs were observed (# affected/10 treated vs. 0/10 controls): decreased 

intraperitoneal adipose tissue in the males (4) and females (8); and decreased subcutaneous 

adipose tissue in females (6). 

At 10,800 ppm, the liver was also a target organ. The following increases were observed in the 

clinical chemistry parameters in the treated group compared to the controls at Week 14: 

cholesterol in both sexes, aspartate aminotransferase in males, and γ-glutamyl transferase in both 
Page 61 of 94 

sexes. Increased absolute and relative to body liver weights were noted in both sexes. Increased 

incidences of evident liver lobules were observed in both sexes as well as increased incidences of 

slight hepatic bile duct hypertrophy and moderate hepatic centrilobular hypertrophy. 

At 10,800 ppm, the heart was a target organ. Increased incidence of myocarditis was observed in 

the males, while increased incidences of myocardial vacuolation were noted in both sexes. 

At 10,800 ppm, the thyroid was a target organ. Increased absolute and/or relative thyroid 

weights in both sexes were noted, and increased incidences of slight thyroid follicular cell 

hypertrophy were observed in both sexes. 

Increased incidence of slight Leydig cell hyperplasia was noted in the testes at 10,800 ppm. 

The LOAEL is 1800 ppm (equivalent to 117.4/143.9 mg/kg/day in males/females), based on 

decreased body weights and body weight gains in females, decreased adipose tissue in both 

sexes, increased blood urea nitrogen and urinary ketones in females, and increased relative 

kidney weights in both sexes. The NOAEL is 300 ppm (equivalent to 20.1/24.7 mg/kg/day 

in males/females). 

This study is classified as acceptable/guideline and satisfies the guideline requirements (OPPTS 

870.3100; OECD 408) for a subchronic oral toxicity study in the rat. 

 870.3100 90-Day Oral Toxicity – Mouse 

In a subchronic oral toxicity study (MRID 47638202), 

NF-149 (Cyflufenamid; 96.4% a.i., Lot # 31-6415-AO) was administered to 10 CD-1 

mice/sex/dose in the diet at dose levels of 0, 100, 400, 1600, or 7000 ppm (equivalent to 0/0, 

14.0/17.6, 50.7/70.8, 218.1/295.1, and 808.0/940.2 mg/kg/day [M/F], respectively) for up to 91 

days. 

No compound-related effects were noted on ophthalmoscopic examinations at any dose in either 

sex. The transient abdominal distension observed at 7000 ppm in 3/10 males on Days 21-27 and 

3-5/10 females on Days 21-32 was considered to be of equivocal toxicological importance. As 

cecal weights (including content) in this group were not significantly increased, the cause of this 

finding was unknown. Additional findings of equivocal toxicological importance at 7000 ppm 

included: an increase in the number of females with elevated levels (15 mg/dL) of ketone bodies 

(7/10 treated vs. 0/10 controls) in the urine, and increases in blood urea nitrogen (incr 29%) and 

total protein (incr 13%) in the females at this dose. 

At 7000 ppm, transient decreases (decr 7-8%) in mean body weights were observed in both sexes 

on Day 1. Additionally at this dose, the males and females displayed significant body weight 

losses on Day 1 (-1.87 g treated vs. 0.56 g controls and -1.44 g treated vs. -0.01 g controls, 

respectively), and body weight gain in the males remained reduced (not statistically significant 

[NS]) by 65% compared to controls on Day 7. All of these findings were transient, and no 
Page 62 of 94 

statistically significant differences in mean body weight and cumulative body weight gains were 

observed during Days 14-91 in any treatment group. In the high-dose groups, decreases were 

observed in both absolute (decr 40-60%) and relative (decr 21-57%) food consumption during 

Days 1-7 and 1-14, respectively. Additionally in the females on Day 63, decreases of 29-30% 

were observed in absolute and relative food consumption. Both absolute and relative food 

consumption were generally decreased throughout the study at this dose in both sexes; however, 

no further statistically significant differences were observed. Food efficiency (%) was decreased 

in the males and females on Day 1 (-183.8% treated vs. 11.8% controls and -72.4% treated vs. -

1.7% controls, respectively). Food efficiency remained decreased in the males at this dose on 

Day 7 (-253% treated vs. 6.9% controls). Beginning on Day 14 in the males and Day 7 in the 

females, food efficiency was generally increased compared to controls throughout most of the 

remainder of the study. The Sponsor stated that the findings in body weights, body weight gain, 

food consumption, and food efficiency indicated a poor palatability of the dietary formulations. 

The primary target organ was the liver. Clinical chemistry findings at this dose included: (i) 

increased ALT levels in the males (incr 515%); (ii) increased AST levels in the males (incr 

110%); (iii) increased total cholesterol in both sexes (incr 72-91%); and (iv) decreased 

albumin/globulin ratio in the males (decr 29%). Both absolute and relative (to body) liver 

weights were increased in the males (incr 89% each) and females (incr 112-116%). Gross 

lesions were limited to dark brown liver in 5 males. Microscopic findings in the liver observed 

in all animals at the high-dose included the following: (i) increased incidence of centrilobular 

hypertrophy (slight to moderate); (ii) focal necrosis (slight to moderate); and (iii) yellow pigment 

in the Kupffer cells (slight). Additional hepatic findings at this dose included: slight nucleolar 

hypertrophy (all males) and decreased fat droplets (6/10 males). 

Additional microscopic findings at 7000 ppm included: (i) slight myocardial vacuolation in 8 

males and 2 females; (ii) testicular Leydig cell hyperplasia (slight) in all males; and (iii) 

decreased secretory granules in the submandibular glands (slight to marked) in 7 males (vs. 1/10 

controls). 

At 1600 ppm, findings were limited to the following: (i) body weight gain was transiently 

decreased by 91% (NS) in the males on Day 1; (ii) both absolute and relative (to body) liver 

weights were increased by 16-18% in the males and 21-28% in the females; and (iii) slight 

centrilobular hypertrophy was noted in 4/10 mice (vs. 0 controls) of each sex. In the absence of 

any clinical chemistry findings, the increased liver weights and slight centrilobular hypertrophy 

were considered to be adaptive and not adverse at this dose. 

At 400 ppm, the minor increase in absolute liver weight (incr 19%) noted in the females was not 

accompanied by a significant increase in relative (to body) liver weight, any significant changes 

in clinical chemistry, or corroborative histopathological findings. 

The LOAEL is 7000 ppm (equivalent to 808.0/940.2 mg/kg/day [M/F]) based on increased 

absolute and relative liver weights, clinical chemistry (increased AST and ALT in males 

and increased cholesterol in both sexes, decreased A/G ratio in males), microscopic hepatic 
Page 63 of 94 

lesions (centrilobular hypertrophy, focal necrosis, and yellow pigment in the Kupffer cells 

in both sexes, and slight nucleolar hypertrophy and decreased fat droplets in males), 

myocardial vacuolation in both sexes, testicular Leydig cell hyperplasia, and decreased 

secretory granules in the submandibular glands in males. The NOAEL is 1600 ppm 

(equivalent to 218.1/295.1 mg/kg/day [M/F]). 

This study is classified as acceptable/guideline and satisfies the guideline requirements (OPPTS 

870.3100a; OECD 408) for a subchronic oral toxicity study in the mouse. 

870.3150 90-Day Oral Toxicity – Dog 

In a subchronic oral toxicity study (MRID 47620504), NF-149 (Cyflufenamid; 95.2% a.i.; Lot 

No. T3G-1020) was administered in the diet to four beagle dogs/sex/dose group at doses of 0, 

150, 500, or 1500 ppm (equivalent to 0/0, 6.5/7.5, 23.2/24.4, and 76.2/70.5 mg/kg/day in 

males/females) for at least 90 days. 

No adverse, treatment-related effects were observed on mortality, clinical signs of toxicity, 

ophthalmoscopic examinations, urinalysis, or gross pathology. 

Systemic toxicity was observed at 1500 ppm. Body weights were decreased in male dogs by 

3-13% during Weeks 2-13, resulting in decreased overall (Weeks 0-13) body weight gains of 

56%. In the females during Weeks 1-13, body weights were decreased by 7-13% and food 

consumption was decreased by 5-25%, resulting in decreased overall body weight gains of 42% 

and decreased overall food consumption of 16%. 

The liver was a target organ, with adverse, treatment-related findings observed at 1500 ppm. 

Absolute and relative (to body) liver weights were increased by 16-36% in the females, and 

relative liver weights were increased by 26% in the males. Activated partial thromboplastin time 

was increased in the females by 18-31% at Weeks 6 and 13. Alkaline phosphatase was increased 

by 144-331% in the males and females on Weeks 6 and 13. Cholesterol was increased by 25% 

in the males on Week 13, and by 31-34% in the females on Weeks 6 and 13. The following 

lesions were observed in the liver, compared to 0/4 controls: (i) enlarged, finely vacuolated 

midzonal and periportal hepatocytes in the males (1/4; moderate severity) and females (1/4; 

slight severity); (ii) slight occasional finely vacuolated hepatocytes in 1/4 males; and (iii) slight 

enlarged finely vacuolated subcapsular hepatocytes in the males (1/4) and females (2/4). Oil Red 

O staining revealed minimal to slight periportal hepatocyte fat in the 500 ppm males and females 

and minimal to marked/severe periportal hepatocyte fat in the 1500 ppm males and females 

(compared to 0/4 controls). Oil Red O staining also revealed marked midzonal hepatocyte fat in 

1/4 females compared to 0/4 controls. 

 

The brain was a target organ. The following lesions were observed in the brain at 1500 ppm, 

compared to 0/4 controls: (i) minimal to marked vacuolation of the neuropil in the vicinity of the 

thalamus-cerebrum in the males (3/4; minimal to moderate severity) and females (4/4); (ii) slight 

to moderate vacuolation of the superficial layer of the cerebral cortex in the males (3/4; slight 
Page 64 of 94 

severity) and females (4/4); (iii) minimal to marked vacuolation of the white matter of the 

cerebrum in the males (2/4; minimal to slight severity) and females (4/4); and (iv) slight 

widespread focal vacuolation of the neuropil of the midbrain in 1/4 females. 

Slight involution/atrophy of the thymus was noted at 1500 ppm in 3/4 males and 2/4 females, 

both compared to 1/4 controls. 

The reviewers disagree with the Sponsor on the adversity of the findings in the liver at 500 ppm. 

Absolute and relative liver weights were increased by 22% in the females, and relative liver 

weights were increased by 16% in the males. Activated partial thromboplastin time was 

increased in the females by 27% at Week 13. Alkaline phosphatase was increased by 64% in the 

females on Week 13. Cholesterol was increased by 29% in the males. Oil Red O staining 

revealed minimal to slight periportal hepatocyte fat in the males and females (3/4 each), 

compared to 0/4 controls. Due to the low magnitude and/or minimal severity of these findings, 

the reviewers consider these findings to be an adaptive response of the liver to administration of 

the test compound at this dose. 

The LOAEL is 1500 ppm (equivalent to 76.2/70.5 mg/kg/day in males/females), based on 

decreased body weights, body weight gains, food consumption, and liver, brain, and 

thymus toxicity as described above, in both sexes. The NOAEL is 500 ppm (equivalent to 

23.2/24.4 mg/kg/day in males/females). 

This study is classified acceptable/guideline and satisfies the guideline requirements (OPPTS 

870.3150; OECD 409) for a subchronic oral toxicity study in dogs. 

 870.3200 21/28-Day Dermal Toxicity – Rat 

In a 28-day dermal toxicity study (MRID 47620428), NF-149 (Cyflufenamid; 95% a.i., Batch # 

T3G-1020) suspended in 5% gum arabic and 0.01% Tween 80 in reverse osmosis treated water 

was applied (2 mL/kg) to the shaved intact skin of 5 CD rats/sex/dose at dose levels of 0, 100, 

300, or 1000 mg/kg/day (limit dose) for 6-7 hours/day, 7 days/week, for 4 weeks. 

No adverse treatment-related effects were observed on mortality, clinical signs of toxicity, 

dermal irritation, body weight, body weight gain, food consumption, food efficiency, 

ophthalmoscopic exams, hematology, clinical chemistry, urinalysis, absolute or relative organ 

weights, and gross or microscopic pathology in either sex. 

The LOAEL was not observed. The NOAEL is 1000 mg/kg/day (limit dose).

This study is classified as acceptable/guideline and satisfies the guideline requirement for a 28-

day dermal toxicity study (OPPTS 870.3200; OECD 410) in rats. 
Page 65 of 94 

A.4.2 Prenatal Developmental Toxicity

 870.3700a Prenatal Developmental Toxicity Study – Rat 

In a developmental toxicity study (MRID 47620506), Cyflufenamid (95.2%; Lot # T3G-1020) 

in aqueous 5% gum arabic and 0.01% Tween 80 was administered via daily oral gavage in a dose 

volume of 10 mL/kg to 22 time-mated presumed pregnant Sprague-Dawley rats/dose group at 

doses of 0, 100, 300, or 1000 mg/kg/day from gestation days (GD) 6-19. On GD 20, all maternal 

rats were euthanized, a gross necropsy performed, and the liver was weighed. Each dam’s uterus 

was removed via cesarean section and its contents examined. The fetuses were examined for 

external, visceral, and skeletal malformations and variations. 

All maternal animals survived until scheduled termination. Maternal body weights, body weight 

gains, and food consumption of the treated groups were comparable to controls throughout the 

study. 

At 1000 mg/kg/day, brown staining was observed on the head in 11 dams compared to 1 control. 

Additionally at 1000 mg/kg/day, brown staining was observed on the dorsal and ventral body 

surfaces, sacral region, forepaws, and pinna, in 1-5 dams per finding compared to 0 controls. 

The following additional findings were observed at this dose (compared to 0 controls): 

ungroomed coat in 3 dams; piloerection in 2 dams; and hair loss on the forelimb in one dam. 

These findings indicate a general unkempt appearance and are considered treatment-related. 

The following findings were noted in the 1000 mg/kg/day group at gross necropsy, confirming 

the clinical signs observed during the treatment period (# affected vs. 0 controls, unless 

otherwise noted): (i) brown staining on the head (9 vs. 1), limbs (8), and body surface (7); (ii) 

ungroomed coat (1); and (iii) hair loss on the limbs (1). Aside from these findings, the only 

macroscopic finding that could be attributed to treatment was slightly enlarged liver lobes in a 

single dam at 1000 mg/kg/day. 

Absolute and relative (to body weight) liver weights were increased (p<0.01) by 12-14% at 300 

mg/kg/day and by 21-22% at 1000 mg/kg/day compared to controls. Relative liver weight was 

also increased (p<0.01) at 100 mg/kg/day; however, this increase was minor (5%) and not 

considered adverse. The reviewers consider the increased liver weights at 300 and 1000 

mg/kg/day to be treatment-related. However, because clinical chemistry and histopathology 

parameters are not examined in a developmental toxicity study, it is not possible to determine 

whether these increases are an adaptive response or if they are adverse. Therefore, these findings 

are considered equivocal. 

The maternal LOAEL is 1000 mg/kg/day based on increased incidences of clinical and 

macroscopic observations indicating an unkempt coat appearance (e.g., brown staining, 

piloerection, and hair loss). The maternal NOAEL is 300 mg/kg/day. 
Page 66 of 94 

There were no abortions, premature deliveries, complete litter resorptions, or dead fetuses. 

There were no effects of treatment on the numbers of litters, live fetuses, early resorptions, or 

late resorptions. Furthermore, sex ratio and post-implantation losses in the treated groups were 

comparable to controls.

There was no evidence of altered growth or development. Fetal body weights and placental 

weights in the treated groups were comparable to controls. There were no dose-related effects on 

ossification of the skeleton.

There were no treatment-related external, visceral, or skeletal variations or malformations. 

The developmental LOAEL was not observed. The developmental NOAEL is 1000 

mg/kg/day (limit dose). 

This study is classified acceptable/guideline and satisfies the guideline requirement (OPPTS 

870.3700a; OECD 414) for a developmental toxicity study in rats.

 870.3700b Prenatal Developmental Toxicity Study - Rabbit

In a developmental toxicity study (MRID 47620508), Cyflufenamid (95.2%; Lot # T3G-1020) in 

aqueous 5% gum arabic and 0.01% Tween 80 was administered via daily oral gavage in a dose 

volume of 5 mL/kg to 26 time-mated presumed pregnant New Zealand White rabbits/dose group 

at doses of 0, 10, 60, or 300 mg/kg/day from gestation days (GD) 6-28. On GD 29, all maternal 

rabbits were euthanized; each dam’s uterus was removed via cesarean section and its contents 

examined. The fetuses were examined for external, visceral, and skeletal malformations and 

variations. 

At 300 mg/kg/day, seven dams aborted prior to GD 29. Clinical signs for these animals included 

weight loss, little diet eaten/few feces, and loose feces. At 60 mg/kg/day, complete litter 

resorption was noted in one dam. All other maternal animals survived until scheduled 

termination. Hair loss on the ventral body surface was dose dependently increased over controls 

at 10 mg/kg/day and above (24-56% dams) compared to controls (16% dams). There were no 

treatment-related gross findings among the animals that survived until scheduled termination. 

Maternal body weight gains in the treated groups at 10 mg/kg/day and above for GD 6-18 were 

dose-dependently decreased (p<0.01) by 44-94% compared to controls, resulting in decreases 

(p<0.05) of 28-67% compared to controls for the overall (GD 6-29) treatment period. Gravid 

uterine weights were unaffected by treatment. Thus, overall body weight gains adjusted for 

gravid uterine weights were decreased by 107-171% in the treated groups compared to controls, 

reflecting the decreases in body weight gains noted during treatment. 

Maternal food consumption was decreased (p<0.05, unless otherwise noted): by 21-26% at 10 

mg/kg/day from GD 13-16; by 8-34% at 60 mg/kg/day from GD 13-21 (Not statistically 

significant; NS) on GD 20; and by 24-58% at 300 mg/kg/day from GD 6-9 and GD 13-25. Total 
Page 67 of 94 

food consumption was 10%, 13%, and 27% lower than controls in the 10, 60, and 300 mg/kg/day 

dams, respectively. 

Because general toxicity was observed at the lowest dose tested (10 mg/kg/day), a subsequent 

study (MRID 47620509) was conducted at doses of 0, 5, and 10 mg/kg/day to establish a 

NOAEL. This study was concurrently reviewed, and a summary is included in Appendix 3 of 

this DER. Although no effects of treatment were observed in the follow-up study at 5 or 10 

mg/kg/day, the reviewers consider the significantly decreased body weights, body weight gains, 

and food consumption in the definitive study to be strong evidence of maternal toxicity. Thus, 

considering the studies in conjunction, the LOAEL is 10 mg/kg/day, and the NOAEL is 5 

mg/kg/day. 

The maternal LOAEL is 10 mg/kg/day based on decreased body weights, body weight 

gains, and food consumption. The maternal NOAEL is 5 mg/kg/day. 

At 300 mg/kg/day, treatment-related abortions occurred in 7 females, resulting in a lower 

number of litters and live fetuses compared to controls. Furthermore, the number of late 

resorptions was higher at this dose, resulting in a higher number of total resorptions. However, 

on a per dam basis for the animals surviving until scheduled termination, there were no effects of 

treatment on the numbers of live fetuses, early resorptions, or late resorptions. Therefore, postimplantation losses in the treated groups were similar to controls. Additionally at 300 

mg/kg/day, 17 placentae from 4 litters were pale compared to 0 controls; 10 of these placentae 

were found in one litter, which was observed with green amniotic fluid.

Fetal body weights were decreased by 8% (p<0.05) in the 60 mg/kg/day females and by 13-20% 

(p<0.01) in the 300 mg/kg/day males and females. Skeletal retardation was evident by the 

following findings: (i) unossified epiphysis at 10 mg/kg/day (5 fetuses; 5 litters), 60 mg/kg/day 

(8 fetuses; 6 litters), and 300 mg/kg/day (22 fetuses; 9 litters); (ii) incomplete ossification and/or 

unossification of the metacarpals and/or phalanges at 10 mg/kg/day (3 fetuses; 2 litters), 60 

mg/kg/day (6 fetuses; 4 litters), and 300 mg/kg/day (6 fetuses; 5 litters); (iii) enlarged 

anterior/posterior fontanelle at 60 (1 fetus) and 300 (4 fetuses; 3 litters) mg/kg/day; (iv) 

unossified area on the cranium at 300 mg/kg/day (2 fetuses; 2 litters); (v) incomplete ossification 

of caudal vertebral element at 300 mg/kg/day (1 fetus); (vi) unossified pubes at 300 mg/kg/day 

(1 fetus); and (vii) unossified astragalus at 300 mg/kg/day (1 fetus). It should be noted that the 

investigators listed the unossification and/or incomplete ossification of epiphyses, metacarpals, 

and/or phalanges at 60 or 300 mg/kg/day to be due to treatment, but did not mention the 

increased incidences in these findings at 10 mg/kg/day compared to controls. The reviewers 

consider the findings at 10 mg/kg/day to be due to treatment.

There were no treatment-related external, visceral, or skeletal malformations or variations. Thus, 

there was no evidence of teratogenicity. 
Page 68 of 94 

The developmental LOAEL is 60 mg/kg/day based on incidences of unossified epiphysis, 

unossification/incomplete ossification of the metacarpals and phalanges, and decreased 

fetal body weight. The NOAEL is 10 mg/kg/day. 

This study is classified acceptable/guideline and, in conjunction with the subsequent 

developmental toxicity study conducted to establish the NOAEL, satisfies the guideline 

requirement (OPPTS 870.3700b; OECD 414) for a developmental toxicity study in rabbits.

A.4.3 Reproductive Toxicity

870.3800 Reproduction and Fertility Effects – Rat 

In a two-generation reproduction toxicity study (MRID 47620514), NF-149 (Cyflufenamid; 

95.2%; Batch #T3G-1020) was administered continuously in the diet at dietary levels of 0, 80, 

250, or 800 ppm (equivalent to 6.6/7.2, 20.5/22.0, and 66.3/72.2 mg/kg/day in males/females, 

respectively) for two consecutive generations. The P generation animals (32/sex/dose group) 

were fed the test diets for 10 weeks prior to mating to produce the F1 litters. F1 offspring 

selected to be parents of the next generation (28/sex/dose group) were fed the same test diet 

concentrations as their parents. F1 parents were fed the test diets for approximately 10-11 weeks 

prior to mating to produce the F2 generation. The F2 offspring were terminated after weaning. 

At 800 ppm in the P generation, four animals were euthanized prior to scheduled termination 

following clinical signs indicating poor general condition. One female was killed for humane 

reasons on GD 15, with no remarkable findings at macroscopic examination. One female was 

killed in extremis on GD 9; examination of this animal at necropsy revealed a perforation in the 

stomach wall and associated adhesions, marked edema, inflammation, and necrosis of the 

submucosa, and marked hyperkeratosis and acanthosis of the keratinized region. Two other 800 

ppm females were killed in extremis on LD 23. Although the condition of one of these dams was 

due to a mammary mass/infection, the second female had numerous poorly defined pale areas on 

the heart, confirmed microscopically to indicate slight acute myocarditis of the auricle and slight 

chronic myocarditis with moderate myocardial mineralization of the ventricle. Additionally in 

this animal, a thickened stomach wall with punctate dark foci on the glandular mucosa was found 

at necropsy, with slight submucosal edema and slight necrosis/hemorrhage of the glandular 

region confirmed microscopically. 

In the F1 generation at 800 ppm, two females were killed in extremis on LDs 1 and 2 following 

clinical signs indicating poor condition. Macroscopic examination at necropsy revealed pale 

liver and pale areas on the keratinized mucosa of the stomach for one female and dark areas on 

the mucosal surface for the other female. Microscopic examination of the stomach revealed 

hyperkeratosis and acanthosis, ulcers and submucosal edema of the keratinized mucosa for one 

female and hemorrhage of the mucosal surface for the second female. Although the Sponsor 

stated that these deaths could not, with any confidence, be attributed to treatment, the reviewers 

consider the deaths at 800 ppm (with the exception of the P dam with the mammary mass) as 

possibly due to treatment. The macroscopic and microscopic findings (perforations, adhesions, 
Page 69 of 94 

edema, necrosis, hemorrhage, hyperkeratosis, acanthosis, and ulcers) may be indicative of a 

direct effect of the test material on the stomach. 

In addition to the findings in the stomach, lesions in the heart in one of the 800 ppm P females 

killed in extremis on LD 23 were likely due to treatment. Microscopic examination of the 

numerous poorly defined pale areas on the heart noted at necropsy revealed slight acute 

myocarditis of the auricle and slight chronic myocarditis with moderate myocardial 

mineralization of the ventricle. In concurrently submitted chronic/oncogenicity studies in rats 

(MRID 47620511) and mice (47638206), heart lesions (including chronic myocardial 

vacuolation in rats and mice, myocarditis in rats, and fat deposition in mice), were noted at the 

highest doses administered (2000 and 4000 ppm). Additionally, a concurrently submitted 

mechanistic study (MRID 47620608) demonstrated that the test material could inhibit rat and 

mouse CPT activity in vitro and may contribute to cardiotoxicity. 

There were no effects of treatment on body weights, body weight gains, food consumption, or 

food efficiency in either sex in either generation during pre-mating. Furthermore, body weights, 

body weight gains, and food consumption in the treated dams were comparable to controls 

during gestation and lactation in both generations. 

In the P generation, absolute and relative liver weights were increased by 8% (p<0.05) over 

controls in the 800 ppm females. None of the 800 ppm males had increased glycogen in the liver 

(0/32 rats) compared to 7/32 controls; this difference was statistically significant (p<0.05). In the 

P females, the incidence of eosinophilic foci of hepatocellular alteration was increased (p<0.05) 

at 800 ppm (4/26 rats) compared to 0/32 controls, and congestion was noted in the liver in 6/26 

rats at 800 ppm compared to 2/32 controls. 

At 800 ppm in the P generation, absolute and relative thyroid/parathyroid weights were increased 

by 13-17% over controls in males and females. These increases were significant (p<0.05), with 

the exception of the absolute thyroid/parathyroid weight in P males. 

In the F1 generation, an increased incidence (not significant) of increased vacuolation of the 

zona fasiculata of the adrenal cortex was observed in the 800 ppm males (4/25) compared to 

controls (0/26). 

 

The LOAEL for parental toxicity is 800 ppm (equivalent to 66.3/72.2 mg/kg/day in 

males/females, respectively) based on: mortality and associated myocarditis in one P dam 

and liver effects in the P generation. The NOAEL is 250 ppm (equivalent to 20.5/22.0 

mg/kg/day in males/females, respectively). 

There were no treatment-related effects on: clinical signs; birth or live birth indices; or pup sex 

ratio for either generation. Furthermore, when dams with complete litter loss were excluded 

from the data (because the mortalities were considered unrelated to treatment, it was apparent 

that the viability and lactation indices in these groups were comparable to controls, indicating 
Page 70 of 94 

that offspring survival was unaffected by treatment. There were no treatment-related 

microscopic findings in the F1 or F2 pups. 

At 800 ppm, pup body weight gains were decreased by 14-23% (p<0.01) in the: F1 males and 

females for PND 14-21; F2 males for PND 4-7, 14-21, and 1-21; and in the F2 females for PND 

4-7 and 14-21. Body weights on PND 21 were significantly decreased (↓13%; p<0.01) in the F2 

males, with non-significant decreases (↓8-9%) noted on PND 21 in the F1 males and females and 

in the F2 females. 

At 800 ppm, relative liver weights were increased by 6-10% (p<0.05) in the F1 males and 

females and in the F2 females compared to controls. Because there were no corroborating gross 

or microscopic lesions in the liver, these increases were considered to be an adaptive response to 

the test material and not adverse. 

The LOAEL for offspring toxicity is 800 ppm (equivalent to 66.3/72.2 mg/kg/day in 

males/females, respectively) based on decreased pup body weights and body weight gains in 

both generations. The NOAEL is 250 ppm (equivalent to 20.5/22.0 mg/kg/day in 

males/females, respectively).

There were no effects of treatment in either generation on: estrous cycle; sperm parameters; 

mating, conception, fertility, or gestation indices; pre-coital interval; or gestation duration in 

either generation. 

The LOAEL for reproductive toxicity was not observed. The NOAEL is 800 ppm 

(equivalent to 66.3/72.2 mg/kg/day in males/females, respectively).

This study is classified as acceptable/guideline and satisfies the guideline requirements (OPPTS 

870.3800; OECD 416) for a two-generation reproduction study in the rat. 

A.4.4 Chronic Toxicity

 870.4100b Chronic Toxicity – Dog 

In a chronic oral toxicity study (MRID 47620505), NF-149 (Cyflufenamid; 95.2% a.i.; Lot No. 

T3G-1020) was administered to four beagle dogs/sex/dose group in the diet at doses of 0, 30, 

120, or 480 ppm (equivalent to 0/0, 1.04/1.08, 4.14/4.41, and 17.29/17.32 mg/kg/day in 

males/females) for 52 weeks. 

No adverse, treatment-related effects were observed on mortality, clinical signs of toxicity, 

neurological or ophthalmoscopic examinations, body weights or body weight gains, food 

consumption, hematology, urinalysis, organ weights, or gross pathology. 

Alkaline phosphatase was increased in the 480 ppm group at Weeks 13, 26, and 52. The 

following findings were observed in the males: slight to moderate focal vacuolation of the zona 
Page 71 of 94 

glomerulosa of the adrenals in two 480 ppm dogs compared to minimal to slight severity in two 

controls; epithelial vacuolar degeneration of the epididymides in one 120 ppm dog (minimal) and 

two 480 ppm dogs (minimal to slight) compared to 0 controls; and minimal to slight 

parenchymal inflammatory cell foci of the liver in two 30 ppm dogs, three 120 ppm dogs, and 

three 480 ppm dogs (slight severity) compared to one control dog (minimal severity). In the 

females, the following findings were noted in the adrenals: focal vacuolation of the zona 

fasciculata in three 30 ppm dogs (minimal to moderate), two 120 ppm dogs (moderate to 

marked), and four 480 ppm dogs (slight to moderate) compared to two controls (minimal to 

slight); and slight diffuse cortical hypertrophy in one 120 ppm dog and two 480 ppm dogs 

compared to 0 controls. 

The reviewers consider these responses treatment-related, but not adverse. The increased 

alkaline phosphatase and slight parenchymal inflammatory cell foci of the liver at 480 ppm 

represent a non-adverse response of the liver to the test compound, and the microscopic findings 

in the adrenals represent an adaptive response. 

The LOAEL was not observed. The NOAEL is 480 ppm (equivalent to 17.29/17.32

mg/kg/day in males/females). 

This study is classified as unacceptable/guideline/not upgradable and does not satisfy the 

guideline requirements (OPPTS 870.4100b; OECD 452) for a chronic oral toxicity study in dogs. 

The dogs were not dosed to the limit dose (1000 mg/kg/day), and could have tolerated a higher 

dose of the test compound. 

A.4.5 Carcinogenicity

 870.4200a Carcinogenicity Study - Rat

In a combined chronic toxicity/carcinogenicity study (MRID 47620511), Cyflufenamid (NF-149; 

95.2% a.i.; Lot No. T3G-1020) was administered in the diet to Crl:CD® rats (60/sex/dose) for up 

to 2 years at doses of 0, 100, 500, 2000 (females only), or 5000 (males only) ppm (equivalent to 

0, 4.4/5.5, 22/28, 115 (females), and 229 (males) mg/kg/day). Additionally, groups of 20 

rats/sex/dose were treated similarly and sacrificed following 1 year of treatment. 

No adverse, treatment-related effect was observed on mortality, food consumption, food 

conversion efficiency, ophthalmoscopic examination, hematology, or urinalysis. 

Generalized systemic toxicity was indicated by the following findings. At 5000/2000 (M/F) 

ppm, increased incidences of the following signs were noted in both sexes (unless noted 

otherwise) during the 2 year treatment period: skin reddening, thin, hunched posture, yellow 

stain (perigenital), flaccid muscle reaction (males only), and brown stain (males only). 

Additionally, palpation for masses determined that there was an increase in the number of 

animals with swellings and in the total number of swellings in both sexes. The mean times of 

onset of the swellings were similar in the treated groups to the controls. After 1 year of 

treatment, increased yellow staining was noted in both sexes and brown staining in males. 
Page 72 of 94 

At 5000/2000 ppm (M/F), body weights were decreased (statistical analysis not performed) in 

both sexes throughout treatment in the carcinogenicity phase (2 year treatment) and in males 

throughout treatment in the toxicity phase (1 year treatment). When all groups were combined 

(n=80), weekly body weight gains were decreased occasionally in the males up to Week 42 (decr 

14-50%) and in the females up to Week 18 (decr 9-29%). Cumulative body weight gains at 

0-26, 0-52, and 0-74 were decreased by 12-13% in males and 3-7% in females. Overall (Weeks 

0-104) body weight gain was decreased by 9% in males and 15% in females. 

At 500 ppm and above, an increased incidence of minimal to moderate chronic myocarditis

(87-93% treated vs. 80% controls) was noted in females following 2 years of treatment. In the 

2000 ppm females, an increased incidence of minimal to moderate chronic myocarditis was 

observed following 1 year of treatment. 

At 500 ppm and above following 2 years of treatment, hepatotoxicity was indicated by the 

increased incidence of slight to severe periportal hepatocytic vacuolation in females (52-55% 

treated vs. 40% controls). 

At 5000/2000 (M/F) ppm, the following findings indicated hepatotoxicity: (i) increased plasma 

γ-glutamyl transferase concentrations in males throughout treatment and in females during 

Weeks 13, 26, and 52; (ii) increased absolute and relative to body liver weights in both sexes 

after both 1 and 2 years of treatment; and (iii) increased swollen liver in both sexes following 2 

years of treatment. Increased incidences of the following findings were noted following 1 year 

of treatment (% treated vs. controls; severity in treated group): (i) periacinar hepatocytic 

hypertrophy in both sexes; (ii) hepatic centriacinar/panacinar hypertrophy in males; and (iii) 

panacinar hepatocytic vacuolation in both sexes. Increased incidences of the following findings 

were noted following 2 years of treatment: centrilobular hepatocellular hypertrophy in both 

sexes; and hepatic focal telangiectasis in females. 

At 500 ppm and above following 2 years of treatment, an increased incidence of minimal to 

moderate thyroid parafollicular cell hyperplasia in females (22-32% treated vs. 15% controls) 

was noted. 

At 5000/2000 (M/F) ppm, absolute and relative to body thyroid weights were increased in males 

after 1 and 2 years and in females after 2 years. Increased incidences of thyroid follicular 

epithelia cell hypertrophy and parathyroid hyperplasia was noted in males following 1 year of 

treatment. Increased incidences of thyroid parafollicular cell hyperplasia and thyroid follicular 

cell hyperplasia were noted in males following 2 years of treatment. 

It was stated by the Sponsor that the changes in the thyroid gland were considered secondary to 

the treatment-induced increased hepatic metabolism of thyroid hormones. The reduction in 

plasma thyroid hormone levels disturbs negative feedback to the pituitary resulting in greater 

thyroid stimulating hormone release and increased thyroid activity. It was stated that this 
Page 73 of 94 

mechanism has been confirmed by the Sponsor in a separate study (study number and details 

were not provided). 

At 500 ppm and above following 1 year of treatment, increased incidences of the following 

findings were observed in the male kidney (% treated vs. controls): slight to moderate cortical 

tubular hyaline droplets (30-80% vs. 5%) and pigmented cortical tubules (50-75% vs. 20%). 

Following 2 years of treatment, increased incidences of minimal to marked progressive (senile) 

nephropathy was observed in females (73-77% treated vs. 57% controls) following 2 years of 

treatment. 

Following 2 years of treatment, increased incidences of minimal to marked adrenal cortical 

hemorrhagic degeneration were noted in males (47-58% vs. 30%). 

At 5000/2000 (M/F) ppm, increased incidences of the following findings in the female kidney 

were noted following 1 year of treatment: renal basophilic cortical tubules, renal cortical tubular 

cast(s), interstitial nephritis, and renal medullary cast(s). Following 2 years of treatment, 

increased incidences of renal pigmented cortical tubules in both sexes were noted. 

In the 2000 ppm females, increased incidences of pancreas acinar atrophy with chronic 

inflammation were observed following 1 and 2 years of treatment. 

In the 2000 ppm females, increased incidences of thymus thyroglossal duct hyperplasia were 

noted following 1 and 2 years of treatment. 

After 2 years of treatment, increased incidences of skin/subcutis mass(es) were observed grossly 

in the 5000 ppm males. Although an increased frequency of axillary lymph node regional to 

mass was noted in the 5000 ppm males, an increase was also noted at 100 ppm; thus, the dosedependency of this effect was equivocal. After 1 year of treatment, an increased incidence of 

mandibular lymph node regional to mass was noted in the 2000 ppm females. A treatmentrelated increase in neoplasia (excluding the thyroid and mammary gland) was not observed; 

therefore, these findings were considered of equivocal toxicological importance.

The LOAEL is 500 ppm (equivalent to 22/28 mg/kg/day in males/females), based on effects 

on the heart, liver, and kidney as detailed above. The NOAEL is 100 ppm (equivalent to 

4.4/5.5 mg/kg/day in males/females).

No increase in neoplasia was noted in the animals of the toxicity phase. Increased incidences of 

the following neoplastic lesions were noted in the 5000 ppm males and/or 2000 ppm females 

during the carcinogenicity phase (# affected/60 in treated group vs. controls): thyroid follicular 

cell adenoma in males (5 vs. 0; p<0.05) and females (2 vs. 0); and thyroid follicular cell 

carcinoma in males (2 vs. 0). The thyroid follicular cell neoplasia incidences exceeded the 

reported background incidences in male CD rats for both adenoma (4-6%) and carcinoma (0-

2%). Background incidence was not provided for females. 
Page 74 of 94 

In the males, the test for trend including all dose groups was statistically significant for benign 

follicular cell adenoma (p=0.034) and for benign follicular cell adenoma and malignant follicular 

carcinoma combined (p=0.004). In both cases, the test was not significant when the high dietary 

concentration group was excluded. 

The Sponsor stated that the effect on the thyroid was due to hepatic enzyme induction, resulting 

in the accelerated degradation of thyroid hormones. This results in chronic stimulation of the 

thyroid through the hypothalmic-pituitary-thyroid axis. This mode of action has been 

documented and is not considered problematic in humans because of differing hormone binding 

profiles and metabolic clearance rate of the thyroid hormones. 

At the doses tested, there was a treatment-related increase in tumor incidence when compared to 

controls. Thyroid follicular cell neoplasia was increased in the rats, but not thought to be 

important in humans. Dosing was considered adequate based on general systemic toxicity and 

effects observed on the heart, liver, kidney, pancreas, and thymus. 

This study is classified as acceptable/guideline and satisfies the guideline requirements (OPPTS 

870.4300; OECD 453) for a combined chronic toxicity/carcinogenicity study in rats. 

 870.4200b Carcinogenicity (feeding) – Mouse 

In a carcinogenicity study (MRID 47638206), Cyflufenamid (NF-149; 95.2% a.i.; Lot No. T3G1020) was administered in the diet to CD1 mice (50/sex/dose) for up to 18 months at doses of 0, 

60, 500, or 4000/2000 ppm (equivalent to 0, 7.1/9.0, 62.8/75.5, and 324.8/403.6 mg/kg bw/day in 

males/females). The dose for the high group was reduced from 4000 ppm to 2000 ppm from 

Week 20, due to mortality and clinical signs of toxicity. 

No treatment-related effects were observed on hematology. 

In the ventricle of the heart, increased incidences of myocardial fibrosis were noted in the 500 

ppm and above males (40%, each treated group vs. 32% controls; slight to marked severity) and 

females (16-20% vs. 6%; slight to moderate). Osteoarthrosis was observed in the femur (with 

joint) of males at 500 (76% treated vs. 68% controls) and 4000/2000 ppm (90%; p<0.05). 

It was considered that 4000 ppm exceeded the maximum tolerated dose, and the high dose 

concentration was reduced to 2000 ppm from Week 20. At 4000 ppm, there was increased 

mortality (particularly in females), and thin build and labored respiration were noted in females. 

Clinical signs observed in these animals prior to death included unresponsive/underactive 

behavior (one female recorded as unconscious), reduced body temperature, piloerection, pallor, 

partially-closed eyes, hunched/prostrate posture, and breathing problems. Decreased (not 

statistically evaluated) body weights were observed in the males throughout treatment and 

females during Weeks 26-78. During the first week of treatment, body weight gains were 

decreased by 71% in males and 48% in females. Overall body weight gains (Weeks 0-78) were 

decreased (p<0.01) in both sexes by 23-25%. Decreased food consumption was observed in both 
Page 75 of 94 

sexes during the first week but this may have been a palatability issue. Food efficiency (Weeks 

1-14) was decreased in the males and equivocally in the females. Macroscopic and microscopic 

examination supported a treatment-related effect in these animals. Gross findings included pale 

livers, livers with areas of change, pale skin, and thin build. 

In the 4000/2000 ppm females, increased (p<0.05) incidences of fine fat deposition and fine 

vacuolation were observed within myocytes of the ventricle. 

At 4000/2000 ppm, absolute and relative to body liver weights were increased in both sexes. In 

the liver, increased incidences of areas of change were noted during necropsy in the 4000/2000 

ppm males. Increased incidences of the following microscopic findings were observed: (i) 

generalized fat deposition in the liver in the males; (ii) fat deposition in the periportal/ 

centrilobular hepatocytes in females; (iii) widespread, finely vacuolated hepatocytes in males; 

(iv) focal, finely vacuolated hepatocytes in males; and (v) loss of hepatocytes and pooling of 

blood in males. 

In the 4000/2000 ppm females, increased incidences of fine vacuolation and fat deposition were 

noted in the cortical tubular epithelium of the kidney. 

The LOAEL is 4000/2000 ppm (equivalent to 325/404 mg/kg bw/day in males/females), 

based on reduced body weight gain, increased liver weight and histopathological findings in 

liver, heart and lungs. The NOAEL is 500 ppm (equivalent to 63/76 mg/kg/day in 

males/females).

Increased incidences of liver masses were observed at necropsy in the 500 ppm males and above 

(30-46% treated vs. 18% controls; p<0.01 at 4000/2000 ppm). Hepatocellular adenoma was 

increased in the 4000/2000 ppm males (34%; p<0.01) compared to the concurrent controls (12%) 

and the range of historical controls (8-31%). There was no increase in incidence of 

hepatocellular carcinoma in males, and there were no incidences of hepatocellular adenomas or 

carcinomas in females. 

At the doses tested, there was a treatment-related increase in hepatocellular adenoma when 

compared to controls. Dosing was considered adequate based on decreased body weights, body 

weight gains, and toxicity observed in the heart, liver, and kidney. 

This study is classified as acceptable/guideline and satisfies the guideline requirement for a 

carcinogenicity study [OPPTS 870.4200b; OECD 451] in mice. 
Page 76 of 94 

A.4.6 Mutagenicity

Gene Mutation

Guideline 870.51000, In vitro Bacterial 

Gene Mutation (Salmonella 

typhimurium/Escherichia coli)/ 

mammalian activation gene mutation 

assay, NF-149 

MRID 47620515 

acceptable/guideline

NF-149 was tested up to the limit of solubility (1500 μg/plate, +/-S9). 

Precipitation of the test material was observed at 1500 (Trial 1, +/-S9) and 5000 

μg/plate (both trials, +/-S9). Evidence of cytotoxicity (thinning of background 

lawn) was observed at 5000 μg/plate in both trials in the presence and absence of 

S9. There were no marked increases in the mean number of revertants/plate in 

any strain in either trial (+/-S9). The positive controls induced the appropriate 

response in all strains in the presence and absence of S9-activation. There was 

no evidence of induced mutant colonies over background.

Guideline 870.51000, In vitro Bacterial 

Gene Mutation (Salmonella 

typhimurium/Escherichia coli)/ 

mammalian activation gene mutation 

assay, 149-(E)-FB, stereoisomer of NF149 

MRID 47620515 

acceptable/guideline

149-(E)-FB was tested up to the limit dose (5000 μg/plate, +/-S9). Precipitation 

of the test material was observed at 5000 μg/plate (+/-S9) in both trials; however, 

no evidence of cytotoxicity (thinning of background lawn and/or reduced number 

of revertants) was observed at any concentration in either trial in the presence or 

absence of S9. There were no marked increases in the mean number of 

revertants/plate in any strain in either trial (+/-S9). The positive controls induced 

the appropriate response in all strains in the presence and absence of S9. There 

was no evidence of induced mutant colonies over background.

Guideline 870.5300, In Vitro Gene 

Mutation assay in mouse lymphoma cells 

MRID 47620516 

acceptable/guideline

NF-149 was tested up to the limit of solubility, upon addition of the test material 

to the cultures and following treatment incubation, a precipitate was observed at 

200 μg/mL (+/-S9) in both trials. No marked increases in cytotoxicity or mutant 

frequency were observed at any concentration with or without S9-activation in 

either trial. The positive controls induced the appropriate response both in the 

presence and absence of S9 in both trials. There was no evidence of induced 

mutant colonies over background in the presence or absence of S9-activation.

 Cytogenetics

Guideline OPPTS 870.5375, In vitro

Mammalian Cytogenetics (Chromosomal 

Aberration Assay in Human Peripheral 

Blood Lymphocytes) 

MRID 47620517 

acceptable/guideline

NF-149 was tested up to cytotoxic concentrations (125 μg/mL and above, -S9 and 

500 μg/mL and above, +S9). Precipitation of the test material was noted at 62.5 

μg/mL and above both in the presence and absence of S9. No statistically 

significant increases in aberration frequencies were observed at any concentration 

evaluated in the presence or absence of S9 in either trial. The positive controls 

induced the appropriate response in the presence and absence of S9 in both trials. 

There was no evidence of chromosome aberrations induced over background 

in the presence or absence of S9-activation.

Guideline 870.5395, In Vivo Mammalian 

Cytogenetics - Erythrocyte Micronucleus 

Assay in Mice 

MRID 47620518 

acceptable/guideline

NF-149 was tested at up to the limit dose (2000 mg/kg). No effects on mortality 

or body weight were observed at any dose. Clinical signs of toxicity (primarily 

hunched posture and piloerection) were observed in both sexes at 1000 and 2000 

mg/kg. No significant decrease in polychromatic erythrocyte to normochromatic 

erythrocyte ratios (PCE:NCE) was observed, indicating that the test material was 

not toxic to the bone marrow. The positive control induced the appropriate 

response. There was no significant increase in the frequency of 

micronucleated polychromatic erythrocytes in bone marrow after either 

treatment time.

 Other Genotoxicity

Guideline 870.5395 Unscheduled DNA 

Synthesis in Primary Rat 

Hepatocytes/Mammalian Cell Cultures 

MRID 47620519 

acceptable/guideline

NF-149 was tested up to the limit dose (2000 mg/kg). No mortalities or clinical 

signs of toxicity were observed at either dose at either exposure time. No marked 

increases in the mean NNG counts were observed in the treated groups at either 

exposure time. The positive controls induced the appropriate response at both 

exposure times. There was no evidence that unscheduled DNA synthesis, as 

determined by radioactive tracer procedures [nuclear silver grain counts], 

was induced.
Page 77 of 94 

A.4.7 Neurotoxicity

 870.6200 Subchronic Neurotoxicity Screening Battery 

In a subchronic neurotoxicity study (MRID 47638205), NF-149 (Cyflufenamid; 95.4% a.i., 

Batch # T3G-1020) was administered in the diet to 10 CD rats/sex/group at dose levels of 0, 200, 

1000, or 5000 ppm (equivalent to 0/0, 18/21, 88/98, and 453/572 mg/kg/day [M/F], respectively) 

for 13 weeks. Neurobehavioral assessment (functional observational battery [FOB] and motor 

activity testing) was performed using all rats at pre-dosing and Weeks 1, 2, 4, 8, and 12. At 

study termination, all surviving animals were anesthetized and perfused in situ for collection of 

tissues for neuropathological examination. The tissues from the 5 lowest numbered rats/sex in 

the control and 5000 ppm groups were subjected to histopathological evaluation of brain and 

peripheral nervous system tissues. Positive control data were not provided. 

No compound-related effects were observed in mortality, clinical signs of toxicity, FOB, motor 

activity, ophthalmoscopic parameters, gross pathology, brain measurements, or neuropathology. 

One 5000 ppm male (No. 29) was sacrificed for humane reasons during Week 13. Prior to 

sacrifice, this animal displayed the following clinical signs: piloerection, thin build, decreased 

fecal pellets, and swollen area on the left ventral abdomen. In the week prior to sacrifice, this 

animal ate significantly less food and lost weight. Gross necropsy revealed pale kidneys, a pale, 

swollen and enlarged liver, and a swollen and enlarged spleen. Histopathological examination 

revealed that this animal had a malignant lymphoma. This finding was considered unrelated to 

treatment, and no evidence of treatment-related carcinogenicity was observed in the concurrently 

reviewed chronic oncogenicity study (MRID 47620511). Body weights (no statistical analyses 

reported) were decreased by 3-8% throughout the study in both sexes, and body weight gains 

were decreased (p<0.01) by 33-54% in both sexes during Week 0-1. Sporadic decreases of 16-

64% in body weight gain were noted at several intervals throughout the treatment period, and a 

body weight loss was noted in the males for Weeks 11-12 (-1g treated vs. 7g controls). Overall 

(Weeks 0-13) body weight gains were decreased by 9% in the males (NS) and by 18% (p<0.05) 

in the females. In the females, food consumption was transiently decreased (no statistical 

analyses reported) by 9% during Weeks 1 and 2. However, overall (Weeks 1-13) food 

consumption was similar to controls at all doses in both sexes. Food efficiency was decreased 

(no statistical analyses reported) during Week 1 (19.0 treated vs. 27.1 controls and 7.0 treated vs. 

13.8 controls) in males and females, respectively, and overall food efficiency was also slightly 

decreased (10.9 treated vs. 12.0 controls and 5.0 treated vs. 6.2 controls) in males and females, 

respectively. 

No compound-related effects were observed at 200 or 1000 mg/kg in either sex. 

No neurological effects were observed at any dose in either sex. 
Page 78 of 94 

The LOAEL is 5000 ppm (equivalent to 453/572 mg/kg/day, M/F) based on decreased body 

weight gain and food efficiency in both sexes. The NOAEL is 1000 ppm (equivalent to 

88/98 mg/kg/day, M/F). 

This study is classified as acceptable/guideline and satisfies the guideline requirement (OPPTS 

870.6200b) for a subchronic neurotoxicity study in rats. 

 870.6300 Developmental Neurotoxicity Study

A.4.8 Metabolism

870.7485 Metabolism – Rat 

In a rat metabolism study (MRIDs 47620520-47620522), [fluorinated phenyl-U-14C] or 

[cyclopropyl-2,3-14C]NF-149 (>=95% radiochemical purity) was administered to SpragueDawley rats (4-16/sex/dose) as a single oral (gavage) dose at 10 or 200 mg/kg or as 14 

consecutive daily doses at 10 mg/kg. In addition, four male and female bile-cannulated SpragueDawley rats were administered a single oral dose of [fluorinated phenyl-U-14C]NF-149 at 10 or 

200 mg/kg. Excreta, blood, and tissues were collected from the treated animals; radioactivity 

was quantified; and metabolites were isolated and identified when possible. 

At 10 mg/kg, 70-85% of the administered dose (AD) was absorbed, while 41-51% AD was 

absorbed at 200 mg/kg. In plasma and blood, Tmax occurred within 1-4 hours in each 10 mg/kg 

group, indicating relatively rapid absorption. At 200 mg/kg, absorption was slower (Tmax

occurred at 6-12 hours). The Cmax ranged from 0.31-1.35 μg equiv/mL at 10 mg/kg to 3.64-17.7 

μg equiv/mL at 200 mg/kg. The increase of Cmax was approximately proportional to the increase 

in dose in the males, but not the females. The half-life in plasma was 14-16 hours in the 10 

mg/kg [fluorinated phenyl-U-14C]NF-149 rats, 6-8 hours in the 10 mg/kg [cyclopropyl-2,3-14C] 

NF-149 rats, and 19 (males) and 34 (females) hours in the 200 mg/kg rats. Half-lives in the 

blood cells were longer than in the plasma. Thus, differences were observed in the 

pharmacokinetic parameters based on sex and dose (apart from a proportional difference based 

on the change in dose), as well as radiolabel position. 

The compound concentrated in the blood cells of whole blood, as demonstrated by residue levels 

that were approximately 1.8 to 2.8-fold higher in blood cells than plasma at 72 hours after dosing 

or 9.7-16.0-fold higher at 168 hours after multiple dosing. The highest concentrations outside of 

the GIT at 4 hours after dosing were detected: in the liver at 10 and 200 mg/kg; and in the 

abdominal fat at 200 mg/kg. The kidney also had relatively high concentrations at the 10 and 

200 mg/kg dose levels, and abdominal fat was relatively high in each of the 10 mg/kg groups. At 

168 hours after dosing of the [fluorinated phenyl-U-14C]NF-149 treated groups, the liver still had 

the highest measured levels (0.481-0.664 μg equiv/g at 10 mg/kg and 2.87-5.92 μg equiv/g at 

200 mg/kg). The highest concentrations were found in females at both doses. At 72 hours 

(terminal sacrifice) after dosing the [cyclopropyl-2,3-14C]NF-149 groups, the abdominal fat had 

the highest measured levels (1.82-2.30 μg equiv/g). 
Page 79 of 94 

Elimination half-lives in the [fluorinated phenyl-U-14C]NF-149 treated groups were typically 

very long for the blood cells in the single dose groups (30-52 hours) and in the multiple dose 

group (133-231 hours), with the highest concentrations found in the females in each group. 

Conversely in the single dose groups, the half-life in plasma was 15-20 hours. The elimination 

half-lives in the pancreas were typically among the lowest measured at 11-14 hours. In the 

multiple dose groups the half-life in plasma was 38-45 hours, and (excluding the GIT) the 

elimination half-life in the abdominal fat was the lowest measured at 31-32 hours. The 

elimination half-lives in tissues corroborate a sex-related difference in the pharmacokinetics of 

the test compound. 

In the groups that were treated with either a single low dose or high dose of [14C]NF-149 (each 

label), the total recoveries were 92-101% AD. Most of the dose was excreted within the first 24 

hours (62-88% AD), with excretion in males being higher than females in each case. Excretion 

occurred primarily through the feces (57-88% AD), but substantial amounts were also isolated in 

the urine (10-32%). Minor quantities of residue were isolated in the cage wash and carcass. In 

the preliminary excretion balance study, the proportion of the dose excreted as volatiles was 

below the limit of detection. 

Males excreted slightly more than the females during the first 24 hours after dosing; and less 

residues were found in the feces and more were found in the urine of males compared to females. 

In the 10 mg/kg [cyclopropyl-2,3-14C]NF-149 group, less radioactive residues were isolated in 

the feces and more in the whole body compared to the [fluorinated phenyl-U-14C]NF-149 group. 

High amounts of the absorbed dose were found in the bile: 61-77% AD at 10 mg/kg and 34-43% 

AD at 200 mg/kg with highest concentrations found in females. The Sponsor stated that a 

substantial proportion of the biliary radioactivity was finally eliminated in the feces at 10 mg/kg, 

and re-absorption of the radioactivity excreted in the bile had likely occurred (enterohepatic 

circulation). 

Excretion during the 24-hour period after dosing occurred primarily through the feces, but 

substantial amounts were also isolated in the urine. The excretion profile was similar for Days 1, 

5, 10, and 14. Less residues were found in the feces and more were found in the urine of males 

compared to females during the 168 hour period following the last dose. No major difference 

was evident in the excretion profiles, based on 14 consecutive doses compared to a single dose. 

In the [fluorinated phenyl-U-14C]NF-149 groups, 149-F1 was the primary urinary metabolite in 

all groups and comparable levels were noted in each group; levels were higher in males than the 

females in each group. In the feces, the parent was present at only 4-5% total radioactive residue 

(TRR) in the animals administered a single gavage dose at 10 mg/kg, but was isolated at 42-50% 

TRR at 200 mg/kg and 24-30% TRR in the multiple dose group. The major metabolites in the 

feces of all groups were 149-F-3-OH-4-OH-B in both sexes (with higher levels observed in the 

females in each group) and 149-F-4-OH-B in the females. In the bile, the major metabolite was 

a mixture of conjugates, including 149-F-3-methoxy-4-OH-B, 149-F-3-OH-4-methoxy-B, and 

149-F-4-OH-B. In the plasma, parent and metabolites 149-F and 149-F1 were found in all dose 
Page 80 of 94 

groups. In the liver, parent was present in all dose groups, but only at minor levels in males 

compared to females. Metabolite 149-F1 was present in all dose groups in the liver, and levels 

were always higher in males than females. Metabolites 149-F6, 149-F, and 149-F4B were also 

found in the liver. In the kidney, parent was present in all dose groups, but large differences 

were observed between sex and dosing regime. The metabolites 149-F1 and 149-F6 were 

present in the kidney in all dose groups. In the fat, parent was present in all dose groups. 149-Fα-OH-B was isolated in the fat in the 10 and 200 mg/kg single-dose males, but only minor 

amounts were noted in the other dose groups. 

In the [cyclopropyl-2,3-14C]NF-149 groups, the only identified metabolite detected in the urine 

was CPCA-Gly. In the feces, 149-F-3-OH-4-OH-B was the major metabolite in both sexes; 149-

F-4-OH-B was also isolated in females. The parent, 149-F-4-OH-B (males) and 149-F-3-OH-B 

were also found in the feces at trace to 5% TRR. 

Thus, differences were observed in metabolic profiles based on sex, dose, and radiolabel. 

The metabolism of [fluorinated phenyl-U-14C]NF-149 in the rat proceeded via two main 

pathways. In one pathway, NF-149 was hydrolyzed to 149-F and then reduced to the amidine 

149-F1. The 149-F1 was then deaminated to form 149-F6. In the other main pathway, 149-F-3-

OH-4-OH-B was formed by di-hydroxylation of the non-fluorinated phenyl ring and was 

subsequently converted to the methoxy derivative. The intermediate mono-hydroxylated 

metabolites 149-F-3-OH-B and 149-F-4-OH-B were also present. Hydroxylation at the α

position occurred as a minor pathway. A minor pathway proceeded via cleavage of the 

cyclopropylmethoxy moiety to form 149-F4B. The 149-F4B was then converted to a 

glucuronide conjugate. 149-F4B was also cyclized to the oxadiazole 149-F12. Conversion of 

NF-149 to the isomer 149-(E)-FB may represent a minor pathway. In the [cyclopropyl-2,3-

14C]NF-149 groups, one or two hydroxylations of NF-149 took place, and these reactions 

sometimes proceeded to the formation of a 2-(cyclopropylcarbonylamino)acetic acid. 

This metabolism study in the rat is classified acceptable/guideline and satisfies the guideline 

requirement for a metabolism study [OPPTS 870.7485, OPP 85-1] in rats. 

A.4.9 Immunotoxicity 

 870.7800 Immunotoxicity – Rat 

In an immunotoxicity study (MRID 47620524), NF-149, cyflufenamid (95.6% a.i., batch no. 

T3G-1020) was administered to 10 Crl:CD(SD) rats/sex/dose in their diet at dose levels of 0, 

300, 1800, or 10800 ppm (0, 24/25, 150, 942/927 mg/kg bw/day, M/F) for 28 days. Four days 

prior to termination, each rat received an intravenous dose of sheep red blood cells (SRBC, 2 x 

108

 cells). A positive control group, consisting of five male and five female rats, received a 

single intraperitoneal dose (50 mg/kg) of cyclophosphamide two days prior to termination. All 

animals were observed daily for evidence of ill-health or treatment-related changes. Body 

weight was recorded on Day 1, then twice weekly throughout the study period and at necropsy. 
Page 81 of 94 

Cage food consumption was measured weekly. After four weeks of treatment, all animals were 

subjected to a detailed necropsy; spleen and thymus weights and micropathology were recorded. 

The T-cell dependent antibody response (TDAR) was assessed using the hemolytic plaque 

forming cell (PFC) assay against SBRC. 

There were no effects of treatment on survival, clinical signs or requisite organ weights. 

Decreased body weight gain was observed in males (↓23%, p < 0.01) and females (↓36, p < 0.01) 

at 10,800 ppm and hepatomegaly was observed in 5/10 high-dose females. 

There was a statistically significant decrease in the numbers of spleen cells and PFC/spleen in 

females receiving 10800 ppm compared to the negative control group. It is pertinent to note that 

there was substantial individual variation within concurrent control values and treatment groups. 

However, the distribution of individual data clearly suggested a decreased activity pattern in the 

high-dose females compared with negative control and other treated groups. There were no 

significant changes in the numbers of PFC/106

 cells or PFC/spleen in females treated with 300 or 

1800 ppm and in all male treatment groups compared with the negative control group. Positive 

control of cyclophosamide demonstrated a near complete suppression of the antibody response to 

the challenge with SRBC in both male and female rats. 

Under the conditions of this study, the LOAEL for T-dependent antibody response in 

females was 10800 ppm (equivalent to 927 mg/kg/day) and the NOAEL is 1800 ppm 

(equivalent to 150 mg/kg/day). The LOAEL for males was not established and the NOAEL 

is 10800 ppm (equivalent to 942 mg/kg/day). 

This study is classified as acceptable/guideline and satisfies the guideline requirement for an 

immunotoxicity study (OPPTS 870.7800) in the rat. 

 870.7800 Immunotoxicity - Mouse 

In an immunotoxicity study (MRID 47620523), NF-149, cyflufenamid (95.6% a.i., Batch no. 

T3G-1020) was administered to 10 Crl:CD1(ICR) mice/sex/dose in their diet at dose levels of 0, 

400, 1600, or 7000 ppm (0, 50/63, 298/388, 1916/2542 mg/kg bw/day, M/F) for 28 days. Four 

days prior to termination, each mouse received a single intravenous dose of sheep red blood cells 

(SRBC, 4 x 108

 cells). A positive control group, consisting of six male and six female mice, 

received 20 mg cyclophosphamid/kg/day via gavage for 5 consecutive days (7 to 3 days prior to 

termination). All animals were observed for evidence of ill-health or treatment-related changes. 

Body weight was recorded on Day 1, then twice weekly throughout the study period and at 

necropsy. Cage food consumption was measured weekly. After four weeks of treatment, all 

animals were subjected to a detailed necropsy; spleen and thymus weight and micropathology 

were recorded. The T-cell dependent antibody response (TDAR) was assessed using the 

hemolytic plaque forming cell (PFC) assay against SRBC. 

One female receiving 7000 ppm was euthanized on Day 23 due to poor clinical condition; 

hypoactivity, reduced body temperature, pallor and tachypnea were all observed prior to death. 
Page 82 of 94 

Necropsy revealed a pale, enlarged liver. There were no effects of treatment on food 

consumption, body weight or body weight gain, clinical signs or requisite organ weights in 

surviving animals. Upon macroscopic examination, enlarged livers were observed in all male 

and the majority of female (7/10) animals treated with 7000 ppm and one male and one female 

treated with 1600 ppm. Liver weights were not recorded. Macroscopic changes were also 

observed in the spleens of high-dose group animals. Enlarged (4/10 vs. 1/10 control) or pale 

(2/10 vs. 0 control) spleens were observed at low incidence, not accompanied by weight change 

and only present in males. While the toxicological significance is unclear, these gross findings 

are not an indicator of immunosuppression. 

There were no statistically significant changes in either the number of PFC/106 cells or 

PFC/spleen for any of the treatment groups compared to the negative control. The data suggest 

that under the conditions of this study, cyflufenamid did not significantly alter the T-cell 

dependent antibody response. The positive control demonstrated marked immunosuppression. 

Upon challenge with SRBC PFC/106 cells, PFC/spleen, and cells/spleen were all suppressed by 

cyclophosphamide treatment. 

No natural killer (NK) cell activity was evaluated because the available toxicity database 

revealed no abnormal findings in organ weights and histopathology in the immune organs. By 

the weight of evidence, it is suggested that the immune system is not a primary target organ for 

cyflufenamid exposure. 

Under the conditions of this study, the LOAEL for the T-cell dependent antibody response 

was not established and the NOAEL is 7000 ppm (equivalent to 1916/2542 mg/kg/day, 

M/F). 

This immunotoxicity study is classified acceptable/guideline and satisfies the guideline 

requirement for an immunotoxicity study (OPPTS 870.7800) in the mouse. 

A.4.9 Special/Other Studies 

In Vitro Inhibition of Porcine Thyroid Peroxidase 

This non-guideline study (MRID 47620606) was performed to determine if NF-149 could inhibit 

porcine thyroid peroxidase, using an in vitro assay to measure activity of this enzyme. A 

microsomal fraction of porcine thyroid glands was prepared, and the inhibitory potential of NF149 (Lot No. T3G-1022; 95.9% a.i.) was determined by monitoring the oxidation of guaiacol, a 

substrate for thyroid peroxidase. Concentrations of the test compound used were 1x10-5 M, 

1x10-4 M, 5x10-4 M, and 1x10-3 M; a vehicle control (90% DMSO solution) was also included. 

6-Propyl-2-thiouracil (PTU), a known inhibitor of thyroid peroxidase, was included as a positive 

control, and was tested at concentrations of 1x10-5 M, 5x10-5 M, 1x10-4 M, and 1x10-3 M. 

Compared to the vehicle control, no suppression of the absorbance increase was observed at any 

concentration of NF-149. The limit of solubility was exceeded at 5x10-4 M and higher, as a 
Page 83 of 94 

white turbid solution was observed. Therefore, the test compound did not inhibit porcine thyroid 

peroxidase at the concentrations tested. 

The positive control (PTU) dilutions caused a concentration-dependent decrease in absorbance 

change, indicating PTU inhibited porcine thyroid peroxidase as expected. Inhibition was 100% 

at the highest concentration (1x10-3 M); and the calculated IC50 was 6.6x10-5 M. 

This study is classified as acceptable/non-guideline. It provides credible supplemental 

information regarding the ability of the test compound to inhibit thyroid peroxidase in vitro. 

Induction of Hepatic Drug Metabolizing Enzymes in Male Mice 

This non-guideline study (MRID 47620607) was performed to determine if NF-149 could induce 

hepatic drug metabolizing enzymes in male mice. Groups of five male CD-1 (Crj:CD-1 [ICR]) 

mice/dose group were administered NF-149 (Lot No. T3G-1022; 95.9% a.i.) in the diet at 

concentrations of 0, 60, or 2000 ppm (equivalent to 0, 9.08, and 292.8 mg/kg/day) for 14 days. 

A positive control group of five male CD-1 mice was concurrently administered the known 

hepatic enzyme inducer phenobarbital in the diet at a concentration of 500 ppm (equivalent to 

62.8 mg/kg/day) for 14 days. Clinical observations, body weights, food consumption, liver 

weights, and macroscopic liver observations were recorded. Microsomal and cytosol fractions 

were prepared from the livers of all mice, and cytochrome P-450 levels and activities of 

sulfotransferase and UDP-glucuronyltransferase were determined. 

There were no test compound-related effects of treatment on mortality, clinical signs, body 

weights, food consumption, liver weights, or gross liver pathology. 

In the 2000 ppm NF-149 group, cytochrome P-450 levels were increased (p≤0.05) by 16% 

compared to controls; UDP-glucuronyltransferase and sulfotransferase were similar to controls. 

While the reviewers agree with the Sponsor that this increase is suggestive of induction of 

hepatic phase 1 enzymes, it must be noted that the level of induction is slight compared to the 

known inducer, phenobarbital (PB). 

Absolute and relative (to body) liver weights were increased (p≤0.01) by 27-29% in the 500 ppm 

PB mice. In the 500 ppm PB group, cytochrome P-450 levels were increased (p≤0.01) by 101%, 

and sulfotransferase activity was increased by 92%. UDP-glucuronyltransferase was not affected 

by PB administration. 

This study is classified as acceptable/non-guideline. It provides supplemental information 

regarding the ability of the test compound to induce hepatic drug metabolizing enzymes in male 

mice. 

In Vitro Inhibition of Rat and Mouse Cardiac Carnitine Palmitoyltransferase 

It was stated that in the chronic studies on NF-149 (assumed by the reviewers to be the 

concurrently submitted chronic toxicity/carcinogenicity study in rats [MRID 47620511] and 18-
Page 84 of 94 

month carcinogenicity study in mice [MRID 47638206]), heart lesions, including myocardial 

vacuolation in rats and mice, myocarditis in rats, and fat deposition in mice were noted at the 

highest doses administered. The inhibition of carnitine palmitoyltransferase (CPT) by NF-149 

was suspected as a mechanism, as CPT plays an important role in the heart in the transport of 

long chain fatty acids into the mitochondrial matrix. Therefore, this non-guideline study (MRID 

47620608) was performed to determine if NF-149 could inhibit rat and mouse CPT, using an in 

vitro assay to measure activity of this enzyme. Microsomal fractions of rat and mouse hearts 

were prepared, and the inhibitory potential of NF-149 (Lot No. T3G-1022; 95.9% a.i.) was 

determined by measuring the release of free CoASH from palmitoyl CoA using 5,5'-dithiobis (2-

nitrobenzoic acid) (DTNB) as a substrate. Concentrations of the test compound used were 0.3, 

0.5, and 1.0 mM. Amiodarone, oxfenicine, and adriamycin, substances known to inhibit CPT 

activity, were also assayed as positive controls to validate the assay. 

NF-149 inhibited rat and mouse CPT by 52% and 51%, respectively, at a concentration of 1.0 

mM. Slight inhibition was also observed at 0.5 mM (15% and 16% in rat and mouse, 

respectively), while no inhibition was noted at 0.3 mM in either species. Each positive control 

substance showed dose-dependent inhibition of CPT in both species. Additionally, it was stated 

that the positive controls inhibited CPT at similar concentrations to those reported in the 

literature, validating the accuracy of the assay. 

Fatty acids are the primary oxidative fuel for cardiac energy production, with lactate and glucose 

providing additional sources of energy. As CPT is involved in the transport of long chain fatty 

acids into the mitochondrial matrix, inhibition of CPT could result in depression of myocardial 

metabolism, including reductions in fatty acid oxidation, TCA cycle, and mitochondrial 

respiration. Therefore, it is possible to attribute the myocardial lesions observed in the 

concurrently submitted chronic toxicity/carcinogenicity studies to inhibition of CPT by the test 

compound. 

This study is classified as acceptable/non-guideline. It provides credible supplemental 

information regarding the ability of the test compound to inhibit rat and mouse CPT in vitro. 
Page 85 of 94 

Appendix B. Metabolism Summary Table 

Table B. Tabular Summary of Metabolites and Degradates.

Chemical Name 

(other names in parentheses) 

and Structure

Matrix Percent TRR (PPM) 1

Matrices - Major 

Residue (>10%TRR)

Matrices - Minor 

Residue (<10%TRR)

Cyflufenamid 

(NF-149) 

[N(Z)]-N-[[(cyclopropylmethoxy)amino][2,3-

difluoro-6-

(trifluoromethyl)phenyl]methylene]benzeneacetamid 

(Z)]-N-[α-(cyclopropylmethoxyimino)-2,3-

difluoro-6-(trifluoromethyl)benzyl]-2-

phenylacetamide 

F

F

N

H

N

O

O

CF3

Apple fruit and leaves; Cucumber fruit and leaves; 

Wheat forage, straw, husks, heads, and grain 

Goat milk, muscle and fat 

Water

Apple (91 

DAT, mature) 

Fruit: 66.2 (0.012) 

Leaves: 16.9 (0.131) 

Cucumber Fruit (L): 55.0-96.3 

(0.019-0.068) 

Fruit (H): 85.8 (0.179) 

Leaves (L): 42.3-97.9 

(0.542-2.91) 

Leaves (H): 67.5-96.3 

(4.50-6.69) 

Wheat 

(Fluorinated 

Phenyl Label 

Study) 

Forage: 90.16-104.07 

(0.621-2.084) 

Straw, immature: 

29.33/38.02 

(0.169/0.737) 

Straw, mature: 

33.40/40.78 

(0.223/0.958 

Husk, mature: 

10.33/19.55 

(0.010/0.106) 

Head, immature: 28.95 

(0.031) 

 Grain, mature: 1.95 

(<0.001) 

Wheat 

(Cyclopropyl 

Label Study) 

Forage: 88.77-101.39 

(0.629-5.064) 

Straw, immature: 

59.06/64.2 

(0.179/1.271) 

Straw, mature: 

55.52/65.17 

(0.171/1.272) 

Husk, mature,: 

16.89/19.92 

(0.057/0.197) 

Head, immature: 

20.09/21.74 

(0.024/0.109) 

 Grain, mature: 6.59 

(<0.004) 

Lactating 

Goat 

 Milk: 6.5 (0.003) 

Fat: 79.8 (0.120) 

Muscle: 21.5 (0.007) 

Rat (feces) male,30.2%; female 

23.5% AD 

Water Not available2 Not available2
Page 86 of 94 

149-(E)-FB 

(E)-N-(α-cyclopropyl-methoxyimino-2,3-difluoro6-trifluoromethylbenzyl)-2-phenylacetamide 

CF3

F

F

N

H

N O

O

Apple fruit and leaves; 

Cucumber fruit and leaves; 

Wheat forage, straw, husks, heads, and grain 

Goat fat

Apple (91 

DAT, mature) 

 Fruit: 1.33 (<0.001) 

 Leaves: 0.670 (<0.005) 

Cucumber Fruit (L): 1.03-1.32 

(<0.001-0.001) 

Fruit (H): 1.36 (0.003) 

 Leaves (L): 1.25-1.79 

(0.16-0.51) 

Leaves (H): 1.25-1.48 

(0.087-0.098) 

Wheat 

(Fluorinated 

Phenyl Label 

Study) 

 Forage: 2.60 (0.021) 

 Straw, immature: 2.04/ 

0.89 (0.012/0.017) 

 Straw, mature: 0.72 

(0.17) 

 Husk, mature: 0.34/0.35 

(<0.001/0.002) 

 Head, immature: 1.34 

(0.001) 

 Grain, mature: 0.09 

(<0.001) 

Wheat 

(Cyclopropyl 

Label Study) 

 Forage: 2.25-3.03 

(0.020-0.114) 

 Straw, immature: 

0.54/3.88 (0.002/0.077) 

 Straw, mature: 

4.28/4.08 (0.013/0.080) 

 Husk, mature: 1.68/0.38 

(0.006/0.004) 

 Head, immature: 

1.05/1.17 (0.001/0.006) 

Lactating 

Goat 

 Fat: 2.5 (0.004) 

149-F 

N-(cyclopropyl-methoxy-2,3-difluoro-6-

trifluoromethylbenzamidine 

Wheat 

(Fluorinated 

Phenyl Label 

Study) 

 Straw immature: 0.28 

(0.005) 

 Straw mature: 2.12/4.10 

(0.014/0.096) 

Lactating 

Goat 

 Fat: 1.4 (0.002) 

 Liver: 14.5/7.4 

(0.016/0.069) 

Rat (feces) male, 3.1%; female, 

3.5% AD 
Page 87 of 94 

CF3

F

F

NH2

N

O

Wheat straw 

Goat fat and liver 

Water

Water Not available2

 Not available2

149-F1 

2,3-difluoro-6-trifluoromethylbenzamidine 

CF3

F

F

NH2

NH

Goat milk, muscle, kidney and liver 

Water 

Lactating 

Goat 

Muscle: 45.5 (0.014) 

Kidney: 14.9/55.5 

(0..002/0.120) 

Liver: 30.6/29.6 

(0.034/0.276) 

Milk: 61.6 (0.025) 

Rat (urine) male, 14.4%; female, 

6.3% AD 

Water Not available2 Not available2

149-F6 

2,3-difluoro-6-trifluoromethylbenzamide 

CF3

F

F

NH2

O

Rotated carrot foliage 

(120-day PBI) 

Goat milk, muscle, kidney and liver 

Water

Carrot Foliage: 32.5 (0.013) 

Lactating 

Goat 

Muscle: 29.9 (0.009) 

Kidney: 17.2/13.9 

(0.003/0.030) 

 Liver: 3.3/8.6 

(0.004/0.080) 

 Milk: 4.3 (0.002) 

Rat (urine) male, 3.0%; female, 

0.6% AD 

Water Not available2 Not available2

149-F-α-OH-B 

(Z)-N-(α-cyclopropyl-methoxyimino-2,3-difluoro-6-

trifluoromethylbenzyl)-2-hydroxy-2-

phenylacetamide 

Cucumber Fruit (L): 0.82-7.14 

(0.001-0.002) 

 Leaves (L): 0.44-2.17 

(0.013—0.041) 

 Leaves (H): 0.55-1.27 

(0.038—0.084) 

Wheat 

(Fluorinated 

Phenyl Label 

Study) 

 Straw, immature: 

2.69/4.64 (0.015-0.090) 

 Straw, mature: 

3.40/4.46 (0.030-0.080) 
Page 88 of 94 

CF3

F

F

N

H

N

O

O

OH

Cucumber fruit and leaves; 

Wheat straw, husks, heads, and grain 

Goat fat 

 Husk, mature: 2.36/3.07 

(0.003-0.013) 

 Head, immature: 1.34 

(0.001) 

 Grain, mature: 0.25 

(<0.001) 

Wheat 

(Cyclopropyl 

Label Study) 

 Straw, immature: 1.36 

(0.004) 

 Husk, mature: 1.32 

(0.013) 

Lactating 

Goat 

 Fat: 1.6 (0.002) 

149-F-α-OH-B-Glu 

Not Provided 

CH2OH

CF3

O

OH

OH

F

F

N

H

N

O

O

O

HO

Cucumber leaves

Cucumber Leaves (L): 0.61-3.36 

(0.015-0.042) 

Leaves (H): 0.12-1.20 

(0.008-0.080) 

 

149-F-2-OH-B 

N-(α-cyclopropyl-methoxyimino-2,3-difluoro-6-

trifluoromethylbenzyl)-2-(2-

hydroxyphenyl)acetamide 

F

F

N

H

N

O

O

CF3

OH

Wheat straw, husks, heads, and grain 

Wheat 

(Fluorinated 

Phenyl Label 

Study) 

 Straw, 

immature:1.10/0.93 

(0.006/0.018) 

 Straw, mature:2.53/1.85 

(0.017/0.043) 

 Husk, mature:1.54/1.47 

(0.001/0.008) 

 Head, immature: 1.65 

(0.002) 

 Grain, mature:0.23 

(<0.001) 

Wheat 

(Cyclopropyl 

Label Study) 

 Straw, immature: 

1.19/0.65 (0.004/0.013) 

 Straw, mature: 

2.33/1.21 (0.007/0.024) 

 Husk, mature: 0.91/0.94 

(0.003/0.009) 

 Head, immature: 

0.11/0.32 

(<0.001/0.002) 
Page 89 of 94 

149-F-3-OH-4-OH-B 

(Z)-N-(α-cyclopropyl-methoxyimino-2,3-difluoro-6-

trifluoromethylbenzyl)-2-(3,4-

dihydroxyphenyl)acetamide 

Rat (feces) 11-27% AD 

149-F-4-OH-B 

(Z)-N-(α-cyclopropyl-methoxyimino-2,3-difluoro-6-

trifluoromethylbenzyl)-2-(4-

hydroxyphenyl)acetamide 

F

F

N

H

N

O

O

CF3

OH

Cucumber fruit and leaves; 

Wheat straw, husks, heads, and grain 

Goat fat

Cucumber Fruit (L): 1.93-8.57 

(0.002-0.006) 

Fruit (H): 7.59 (0.016) 

Leaves (L): 0.18-0.57 

(0.004-0.013) 

Leaves (H): 0.06-0.30 

(0.004-0.020) 

Wheat 

(Fluorinated 

Phenyl Label 

Study) 

 Straw, immature: 

2.0/2.88 (0.017/0.039) 

 Straw, mature: 

1.96/2.24 (0.015/0.046) 

 Husk, mature: 2.21/2.67 

(0.003/0.12) 

 Head, immature: 3.45 

(0.004) 

 Grain, mature: 0.40 

(<0.001) 

Wheat 

(Cyclopropyl 

Label Study) 

 Straw, immature: 1.37 

(0.027) 

 Straw, mature: 

5.12/2.04 (0.016/0.04) 

 Husk, mature: 4.71/2.02 

(0.016/0.020) 

 Head, immature: 

0.22/0.39 

(<0.001/0.002) 

Lactating 

Goat 

 Fat: 1.5 (0.002) 

Rat (feces) male, 5.3%; female, 

18.5% AD 

149-F-4-OH-B-Glu 

N-(α-cyclopropylmethoxyimino-2,3-difluoro-6-

trifluoromethylbenzyl)-2-(4-β-D-glucopyranosyl)-

phenyl)acetamide 

Apple (91 

DAT,mature) 

 Leaves: 8 (0.062) 

Cucumber Fruit(H): 1.42 (0.003) 

 Leaves(L): 0.53-8.54 

(0.013-0.108) 

Leaves(H): 0.56-3.82 

(0.039-0.254) 
Page 90 of 94 

O

OH

OH

HO

O

F

F

N

H

N

O

O

CF3

CH2OH

Apple leaves; 

Cucumber fruit and leaves; 

 

149-F4B-Glu 

N-(β-glucopyranosylimino-2,3-difluoro-6-

trifluoromethylbenzyl)-2-phenyl-acetamide 

CH2OH

O

OH

OH

HO

O

F

F

N

H

N O

CF3

Apple leaves 

Wheat straw and husks 

Apple Leaves: 6.6 (0.051) 

Wheat 

(Fluorinated 

Phenyl Label 

Study) 

 Straw, immature: 

3.67/2.50 (0.021/0.049) 

 Straw, mature: 0.70 

(0.16) 

 Husk, mature: 3.48 

(0.019) 

 
Page 91 of 94 

149-F11 

(Z)]-N-(α-cyclopropylmethoxyimino-2,3-difluoro-6-

(trifluoromethylbenzyl)carbamoylacetic acid 

N

H

N O O F

F

CF3

O

OH

Water 

Water Not available2 Not available2

Apple: 47620805; 0.241 lb ai/A (Broadcast foliar spray); 0-91-day PHI (mature). 

Cucumber: 47620806; 0.045 and 0.178 lb ai/A (Broadcast foliar spray); 0-31-day PHI/7/35-day PHI (0.178 lb ai/A). 

Wheat: 47620809; 0.044 and 0.0178 lb ai/A (Broadcast foliar spray); 0-77-day PHI (mature). 

Wheat: 47638210; 0.044 and 0.0178 lb ai/A (Broadcast foliar spray); 0-53-day PHI (mature). 

Rotational Crops (Carrot, Lettuce and Wheat): 47620811; 0.045 lb ai/A 1x, applied to bare sandy loam soil; 30,120,270-days 

PBI. no parent or metabolites identified. 

Goat; 47620810; 1.2 and 13.3 ppm; 1x; 5 days; 23-hour after last dose administration.. 

Rat: MRID No 47620520 through 47620522; study design of 8 rats/sex receiving 10 mg/kg for 14 consecutive days, 

[fluorinated phenyl-U-14C]NF-149. 

Water: DP#360795, R.F.H. Bohaty, 3/4/2010

1

 When the study was conducted at both a nominal and high application or dosing rate, both results are listed in the table; (L) - 

low rate; (H) - high rate. 

2

 Data are not available on individual components of the residue in water. 
Page 92 of 94 

Appendix C. Review of Human Research 

This risk assessment relies in part on data from studies in which adult human subjects were 

intentionally exposed to a pesticide to determine their dermal and inhalation exposure. Many 

such studies, involving exposure to many different pesticides, comprise generic pesticide 

exposure databases such as PHED and the Outdoor Residential Exposure Task Force (ORETF). 

EPA has reviewed all the studies supporting these multi-pesticide generic exposure databases, 

and has found no clear and convincing evidence that the conduct of any of them was either 

fundamentally unethical or significantly deficient relative to the ethical standards prevailing at 

the time the research was conducted. All applicable requirements of EPA’s Rule for the 

Protection of Human Subjects of Research (40 CFR Part 26) have been satisfied, and there is no 

regulatory barrier to continued reliance on these studies. 
Page 93 of 94 

Appendix D. International Residue Limit Status Sheet 

INTERNATIONAL RESIDUE LIMIT STATUS 

Chemical Name: [N(Z)]-N-

[[(cyclopropylmethoxy)-

amino][2,3-difluoro-6-

(trifluoromethyl)phenyl]-

methylene]benzeneacetamid

e 

Common Name: 

Cyflufenamid 

□ Proposed tolerance 

□ Reevaluated tolerance 

X Other-Recommended 

Date: 11/10/09 

Codex Status (Maximum Residue Limits) U. S. Tolerances 

X No Codex proposal step 6 or above 

□ No Codex proposal step 6 or above for the crops 

requested 

Petition Number: PP#8F7488 

DP#: 364556 

Other Identifier: 

Residue definition (step 8/CXL): N/A Reviewer/Branch: M. Negussie/RAB3 

Residue definition: cyflufenamid 

Crop (s) MRL (mg/kg) Crops Proposed Tolerances 

(ppm) 

 Fruit, pome, group 11 0.06 

 Apple, wet pomace 0.10 

 Vegetable, cucurbit, group 9 0.07 

 Fruit, small vine climbing, 

subgroup 13-07F, except fuzzy 

kiwifruit 

0.15 

 Grape, raisin 0.30 

 Berry, low growing, subgroup 

13-07G, except cranberry 

0.20 

Limits for Canada Limits for Mexico 

X No Limits 

□ No Limits for the crops requested 

X No Limits 

□ No Limits for the crops requested 

Residue definition: N/A Residue definition: N/A 

Crop(s) MRL (mg/kg) Crop(s) MRL (mg/kg) 

 

Notes/Special Instructions: S. Funk, 11/10/2009. 

 
Page 94 of 94 

Appendix E. Data Required as a Condition of Registration 

Table E. Description of Outstanding Studies 

Guideline Number: 870.6200 

Study Title: Neurotoxicity Battery (Acute Studies) 

Rationale for Requiring the Data 

This is a new data requirement under 40 CFR Part 158 as a part of the data requirements 

for registration of a pesticide (food and non-food uses). 

The Neurotoxicity Screening Battery (OPPTS 870.6200) is designed to evaluate the 

potential adverse effects on the nervous system from exposure to pesticide chemicals. 

The Agency believes that the guideline studies are inadequate in their assessment of 

behavioral effects and do not use optimal methods to evaluate the potential toxicity to the 

nervous tissue structure and function. To detect and characterize these potential effects 

more fully, a battery of more sensitive testing is required. The objective of this 

neurotoxicity battery testing is to evaluate the incidence and severity of the functional 

and/or behavioral effects, the level of motor activity, and the histopathology of the 

nervous system. The acute neurotoxicity study is required to detect possible effects 

resulting from a single exposure. 

Practical Utility of the Data 

How will the data be used? 

The acute neurotoxicity study provides critical scientific information needed to 

characterize potential hazard to the human population on the nervous system from 

pesticide exposure. This study can provide data on a wide range of functional tests for 

evaluating neurotoxicity including sensory effects, neuromuscular effects, learning and 

memory and histopathology of the nervous system For example, animal studies with 

organophosphorous chemicals have shown neurotoxicity to be the primary toxic 

endpoints (e.g., cholinesterase inhibition) of concerns in rodents and non-rodents. This 

animal study can be used to select endpoints and doses for use in risk assessment of all 

exposure scenarios and is considered a primary data source for reliable acute reference 

dose calculation. The Agency has established an oral acute reference dose (RfD) for 

assessing dietary risks for a number of chemicals (e.g., organophosphates and 

carbamates) here neurotoxicity was the most sensitive endpoint of concern. 

How could the data impact the Agency's future decision-making? 

If the acute neurotoxicity study show that cyflufenamid poses a greater risk than that 

given in the interim decision’s conclusion, the risk assessments for cyflufenamid may 

need to be revised to reflect the magnitude of potential risk derived from the new data. 

 

If the Agency does not have this data, a 10X database uncertainty factor may be applied 

when conducting a risk assessment using the currently available studies.