Date: 

Subject: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

August 5, 2014 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

Flupyradifurone: Human Health Risk Assessment for the First Food Use on: 

Root Vegetables Except Sugar Beet (Subgroup 1 B), Tuberous and Corm 

Vegetables (Subgroup 1C), Bulb Vegetables (Group 3-07), Leafy Vegetables 

(Except Brassica) (Group 4), Taro Leaves, Turnip Tops, Head and Stem Brassica 

Vegetables (Subgroup SA), Leafy Brassica Greens Vegetables (Subgroup SB), 

Edible-Podded Legume Vegetables (Subgroup 6A), Succulent Shelled Pea and 

Bean (Subgroup 6B), Died Shelled Pea and Bean (except Soybean) (Subgroup 

6C), Foliage of Legume Vegetables (except Soybean) (Subgroup 7A), Soybean 

(Seed), Fruiting Vegetables Except Cucurbits (Group 8-1 0), Cucurbit Vegetables 

(Group 9), Citrus Fruits (Group 10-1 0), Po me Fruits (Group 11-1 0), Bushberry 

(Subgroup 13-07B) except Cranberry, Small Fruit Vine Climbing (Except Fuzzy 

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

Cranberry, Tree Nuts (Group 14-12), Cereal Grains Except Rice (Crop Group 

15, Except Rice), Forage, Fodder and Straw of Cereal Grains (Crop Group 16), 

Nongrass Animal Feeds (Forage, Fodder, Straw and Hay) (Group 18), Cottonseed 

(Subgroup 20C), Coffee, Hops, Peanuts, Prickly Pear Cactus, and Pitaya. 

PC Code: 122304 

Decision No.: 471642 

Petition No.: 2F81 0 I 

DP Barcode: 0407063 

Registration Nos.: 264-RRUE, 264-RURR 

Regulatory Action: 

Risk Assessment Type: Aggregate Risk Assessment 

TXRNo.:NA 

MRIDNo.:NA 

Case No.: N A 

CAS No.: 951659-40-8 

40CFR:NA 

FROM: Kristin 

Meheret 

Steve Funk, 

Rury, 

Negussie

Sen

Biologist 

io

, 

r 

Chemist 

Chemist 

¥-~ 

~ 

,.4 

LAP ~(k{ _ ~ 

Whang Phang, Senior Toxicologist A 

Vincent Chen, Toxicologist -""L.- _, ___ _,__ 

Risk Assessment Branch III 

Health Effects Division (7509P) 

THROUGH: Christine Olinger, Branch Chi~f W ._/ / .. 

Healt

Risk Assessment 

h Effects Division 

Branch 

(7509 

III ~ 

TO: Jessica Rogala, Risk Manager Reviewer 

Insecticide Branch 

Registration Division (7505P) 

Page 1 of116 
Table of Contents 

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

2.0 HED Recommendations ........................................................... ......................................... 7 

2.1 Data Deficiencies ................................... ............................................................ ............. 7 

2.2 Tolerance Considerations ............. ................................................................................. 7 

2.2.1 Enforcement Analytical Method ......... ........ ..................................................... .... .... ..... 7 

2.2.2 Recommended Tolerances .......................................................... ................................... 8 

2.2.3 Revisions to Petitioned-For Tolerances ............................................................ : ......... 11 

2.2.4 International Harmonization ...................................................................................... 14 

2.3 Label Recommendations .............................................................................................. 14 

2.3.1 Recommendations from Residue Reviews ................................................................. 14 

3.0 Introduction .... ............................................................................................................. ..... 15 

3.1 Chemical Identity ......................................................................................................... 15 

3.2 Physical/Chemical Characteristics ....................................................................... .... .. 15 

3.3 Pesticide Use Pattern ................................ .................................................................... 16 

3.4 Anticipated Exposure Pathways ................................................................................. 21 

3.5 Consideration of Environmental Justice .................................... ........ .... .................... 22 

4.0 Hazard Characterization and Dose-Response Assessment .......................................... 22 

4.1 Toxicology Studies Available for Analysis ................ ........ .............. ...... ..................... 22 

4.2 Absorption, Distribution, Metabolism, & Elimination (ADME) ............................. 23 

4.2.1 Dermal Absorption .... ................................................................................................... 25 

4.3 Toxicological Effects .................................................................................................... 25 

4.4 Safety Factor for Infants and Children (FQPA Safety Factor) ............................... 27 

4.4.1 Completeness of the Toxicology Database ................................................................. 27 

4.4.2 Evidence of Neurotoxicity ....... .... .... .... ................ ....... ........ .... .... ....... ......... ..... .... .... ..... 27 

4.4.3 Evidence of Sensitivity/Susceptibility in the Developing or Young Animal ........... 27 

4.4.4 Residual Uncertainty in the Exposure Database ....................................................... 28 

4.5 Toxicity Endpoint and Point of Departure Selections .............................................. 28 

4.5.1 Dose-Response Assessment ........ .................................................................................. 28 

4.5.2 Recommendation for Combining Routes of Exposures for Risk Assessment ........ 28 

4.5.3 Cancer Classification and Risk Assessment Recommendation ................................ 29 

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

Assessment ....................................................................................... .... ........ ............................ 29 

5.0 Dietary Exposure and Risk Assessment.. .......... ...................................................... .... ... 30 

5.1 Metabolite/Degradate Residue Profile ....................................................................... 30 

5.1.1 Summary of Plant and Animal Metabolism Studies ................................................. 30 

5.1.2 Summary of Environmental Degradation .................................................................. 31 

5.1.3 Comparison of Metabolic Pathways ........................................................................ ... 32 

5.1.4 Residues of Concern Summary and Rationale .............. ........ .................................... 33 

5.2 Food Residue Profile ............................ ............ ........................................ .... .... ............ 35 

5.3 Water Residue Profile .............................................. .................................................... 35 

5.4 Dietary Risk Assessment ...................................................................... .... .................... 36 

5.4.1 Description of Residue Data Used in Dietary Assessment.. ...................................... 36 

5.4.2 Percent Crop Treated Used in Dietary Assessment .............. .................... ................ 36 

5.4.3 Acute Dietary Risk Assessment.. ................................................................ ......... ........ 3 7 

Page 2 of 116 
Page 3 of 116

5.4.4 Chronic Dietary Risk Assessment............................................................................... 37

5.4.5 Cancer Dietary Risk Assessment ................................................................................ 37

5.4.6 Summary Table ............................................................................................................ 37

6.0 Residential (Non-Occupational) Exposure/Risk Characterization ............................. 38

6.1 Residential Bystander Post-application Inhalation Exposure ................................. 38

6.2 Spray Drift.................................................................................................................... 39

7.0 Aggregate Exposure/Risk Characterization.................................................................. 39

8.0 Cumulative Exposure/Risk Characterization ............................................................... 39

9.0 Occupational Exposure/Risk Characterization ............................................................ 40

9.1 Short-/Intermediate-Term Occupational Handler Risk........................................... 40

9.2 Short-/Intermediate-Term Post-Application Risk .................................................... 41

9.2.1 Dermal Post-application Risk ..................................................................................... 41

9.2.2 Inhalation Post-application Risk................................................................................. 42

10.0 References......................................................................................................................... 43

Appendix A. Toxicology Profile and Executive Summaries .................................................. 45

A.1 Toxicology Data Requirements................................................................................... 45

A.2 Toxicity Profiles............................................................................................................ 46

A.3 Hazard Identification and Endpoint Selection .......................................................... 56

A.4 Executive Summaries................................................................................................... 58

A.5 Flupyradifurone: Summary of NOAEL/LOAEL (with BW 3⁄4 scaling for human 

equivalent dose)....................................................................................................................... 85

Appendix B. Metabolism Summary Table ............................................................................... 87

Appendix C. Physical/Chemical Properties and Metabolites ................................................ 87

Appendix D. Review of Human Research.............................................................................. 102

Appendix E. Qualitative Evaluation of DFA......................................................................... 103

Appendix F. Occupational Exposure Tables........................................................................ 106
Page 4 of 116

1.0 Executive Summary

Flupyradifurone (BYI 02960) is a new butenolide insecticide currently undergoing global joint 

review (GJR) with Australia, Brazil, Canada, and Mexico. Butenolide insecticides, like nicotine

and neonicotinoid insecticides, bind to nicotinic acetylcholine receptors (nAchR). Once the 

flupyradifurone binds to the receptor, the receptor is blocked causing insect death. 

Proposed Use Profile

Bayer CropScience has proposed one technical and two end-use product (EP) registrations: 

SivantoTM (EPA Reg. No. 264-RRUR) and BYI 02960 480 FS (EPA Reg. No. 264-RRUE). 

SivantoTM may be applied at single application rates ranging from 7.0 – 28 fl oz/A (0.091 – 0.365 

lb ai/A), with a maximum seasonal application rate of 0.365 lb ai/A to the numerous proposed 

agricultural crops via ground, aerial, or chemigation equipment. The proposed SivantoTM label 

requires occupational handlers to wear the following personal protective equipment (PPE): long 

sleeved shirts, long pants, shoes, socks, and chemical resistant gloves. The proposed restricted 

entry interval (REI) is four hours. 

BYI 02960 480 FS may be applied as a single seed treatment application at a rate of 0.045 –

0.068 mg ai/seed (0.00036 - 0.00054 lb ai/lb seed). The soybean seeds are treated with standard 

slurry or mist commercial seed treatment equipment. The proposed seed treatment label requires 

seed treaters and workers cleaning the treatment facilities to wear the following PPE: long 

sleeved shirts, long pants, shoes, socks, and chemical resistant gloves. Baggers and others 

involved in the packaging of treated seed are required to wear long sleeved shirts, long pants, 

shoes, and socks. 

There are no proposed residential uses of flupyradifurone. 

Exposure Profile

There is potential for occupational short- and intermediate-term dermal and inhalation exposure 

to flupyradifurone during mixing, loading, applying, and post-application activities. There is 

also potential for acute and chronic exposure through food and drinking water from the proposed 

uses of flupyradifurone. 

Toxicity/Hazard

The most sensitive effects seen in the flupyradifurone database were skeletal muscle 

atrophy/degeneration in dogs. With repeated dosing, reductions in body weight and food 

consumption were commonly seen in various studies and in all species of test animals (rats, 

mice, dogs, and rabbits). The liver and thyroid were shown to be the common findings of 

flupyradifurone toxicity. The database appears to suggest that dogs are more sensitive to the 

effects of flupyradifurone; however, with body weight adjustments (based on a 3⁄4 scaling factor –

shown in Appendix A.5), the dog and rat are almost equally as sensitive in response to 

flupyradifurone toxicity. The skeletal muscle atrophy/degeneration seen in the 90-day and oneyear dog studies formed the basis for chronic dietary exposure and short- and intermediate-term 

occupational toxicity endpoints. The points of departure (PODs) were 7.8 mg/kg/day and 12 

mg/kg/day for chronic dietary exposure and for short- and intermediate-term occupational 
Page 5 of 116

exposure assessments, respectively. The developmental toxicity study in rats demonstrated no 

evidence of susceptibility in developing animals. In the rabbit developmental toxicity study, 

there was an increase in the incidence of fetal death at 80 mg/kg/day (the highest dose tested), a 

dose that did not produce adverse effects in the maternal animals. Therefore, a quantitative 

increase in susceptibility was demonstrated in the rabbit developmental toxicity study. In the 2-

generation reproduction study in rats, decreased parental body weights (> 10%) were seen at the 

LOAEL of 137 mg/kg/day (parental NOAEL = 37.8 mg/kg/day). In contrast, body weight 

decreases that were considered adverse were seen in F2 pups at 37.8 mg/kg/day (the parental 

NOAEL and the offspring LOAEL; offspring NOAEL = 7.7 mg/kg/day). These findings suggest 

quantitative susceptibility for developing young animals. Although flupyradifurone produced 

quantitative susceptibility in rabbit developmental toxicity study and qualitative susceptibility in 

the rat reproductive toxicity study, the PODs selected for risk assessment are protective of the 

effects seen in the developing fetuses and young animals. Therefore, there are no concerns for 

reproductive or developmental toxicity of flupyradifurone, and no concerns for increased 

susceptibility to the developing young. HED presently has sufficient information to evaluate the 

hazards associated with exposure to flupyradifurone at this time and the Food Quality Protection 

Act (FQPA) safety factor has been reduced to 1X. Flupyradifurone also produced clinical signs 

(piloerection and pupillary dilatation) indicative of neurotoxicity in the acute neurotoxicity study, 

and these clinical signs were used to establish the toxicity endpoint with a point of departure of 

35 mg/kg for acute dietary exposure assessment. The exposure databases are complete or are 

estimated based on data that reasonably account for potential exposures. 

 

Flupyradifurone is classified as “not likely to be carcinogenic to humans.” Flupyradifurone 

exhibits low acute mammalian toxicity via oral, dermal, and inhalation routes of exposure 

(Category III or IV for acute lethality and irritation studies) and is not a dermal irritant or 

sensitizer. HED waived the requirement for the subchronic inhalation toxicity study

(TXR#0056903). 

Dietary Exposure (Food and Water) and Risk Estimates

Unrefined acute and chronic dietary analyses were conducted for flupyradifurone; the 

assessments incorporated recommended tolerance-level residues and default or empirical 

processing factors, conservative drinking water estimates, and assumed that 100% of the 

proposed crops were treated. The results of the acute and chronic analyses do not exceed the 

Agency’s level of concern (LOC) for the general U.S. population and all population subgroups. 

At the 95th percentile of exposure, the acute dietary (food and drinking water) risk estimates 

utilized 24% of the acute population adjust dose (aPAD) for the general U.S. population and 

utilized 38% of the aPAD for children 1-2 years old, the most highly exposed population 

subgroup. The chronic dietary (food and drinking water) risk estimates utilized 39% of the 

chronic population adjusted dose (cPAD) for the general U.S. population and utilized 84% of the 

cPAD for children 1-2 years old, the most highly exposed population subgroup. 

Studies submitted in support of the registration of flupyradifurone indicate that there could be 

exposure to difluoroacetic acid (DFA) in drinking water and in food (plants and animals). DFA 

was shown to be a mammalian metabolite with approximately 6% of flupyradifurone 

administered to rats being converted to DFA, and DFA was a metabolite in the ruminant and 

poultry metabolism studies. The most sensitive toxic effects to be used in the risk assessment for 
Page 6 of 116

flupyradifurone would not be expected from DFA, which has a very different chemical structure. 

A range-finding and subchronic toxicity study with DFA showed a similar potency to but

different toxic effects (black foci in the glandular part of the stomach) than the parent compound

(skeletal muscle atrophy and degeneration in dogs, and decreased body weight and food 

consumption in rats, mice, dogs, and rabbits), indicating that risk from DFA should be assessed 

separately from the parent. 

The Agency conducted a conservative screening-level chronic dietary exposure evaluation to 

estimate risks from DFA. This evaluation assumed conservative drinking water concentrations, 

that 100% of the crops contained DFA at median residue values. The screening exposure 

evaluation of DFA showed 5-7X less exposure to DFA than to flupyradifurone. Therefore, since 

there is similar potency (albeit with different toxic effects) between flupyradifurone and DFA but 

less exposure expected to DFA than flupyradifurone, the Agency has no additional risk concerns 

about exposure to DFA.

Aggregate Exposure Risk Estimates

The only relevant aggregate risk assessments for flupyradifurone include acute and chronic 

exposure to residues in food and drinking water. The acute and chronic dietary risk assessments 

for the U.S. population and all population subgroups do not exceed the Agency’s LOC (<100% 

PAD), as described above.

Occupational Risk

A short- and intermediate-term occupational risk assessment was performed for flupyradifurone 

use on the proposed crops and for the proposed seed treatment use. The LOC for occupational 

handler and post-application risk is a margin of exposure (MOE) < 100. There are no 

occupational handler risk estimates of concern for the proposed uses of flupyradifurone assuming 

baseline clothing (i.e., no PPE); for the agricultural uses of flupyradifurone, the short- and 

intermediate-term combined (dermal + inhalation) occupational handler MOEs ranged from 260 

to 95,000. With the addition of gloves, as required on the flupyradifurone label, the short- and 

intermediate-term combined (dermal + inhalation) occupational handler MOEs ranged from 800 

to 95,000. For the proposed seed treatment use of flupyradifurone, the combined (dermal + 

inhalation) short- and intermediate-term MOEs ranged from 2,000 to 14,000.

The occupational short-term post-application risk estimates resulted in dermal MOEs of >170 on 

the day of application and were not of concern. Based on the Agency's current practices, a 

quantitative non-cancer occupational post-application inhalation exposure assessment was not 

performed for flupyradifurone at this time. If new policies or procedures are put into place, the 

Agency may revisit the need for a quantitative occupational post-application inhalation exposure 

assessment for flupyradifurone. 

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 data, which include studies from 

Pesticide Handlers Exposure Database (PHED 1.1); the Agricultural Handlers Exposure Task 

Force (AHETF) database; ExpoSAC Policy 14, 15.1 (SOPs for Seed Treatment) and The 

Reviewer’s Aid to Calculating Occupational Exposure From Activities Related to Agricultural 
Page 7 of 116

Seed Treatment; and the Agricultural Reentry Task Force (ARTF) database; are (1) subject to 

ethics review pursuant to 40 CFR 26, (2) have received that review, and (3) are compliant with 

applicable ethics requirements. For certain studies, the ethics review may have included review 

by the Human Studies Review Board. For citations of these data, see Appendix D. 

Environmental Justice

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).

2.0 HED Recommendations

Provided revised petition Sections B and F are submitted, there are no deficiencies that would 

preclude granting a Section 3 registration on the proposed crops. The specific tolerance 

recommendations are detailed in Section 2.2.2, and revisions to petitioned-for tolerances are 

discussed in Section 2.2.3.

2.1 Data Deficiencies

Guideline 875.2100 – Dislodgeable Foliar Residue Data

Since the highest estimated occupational post-application exposure using default dislodgeable 

foliar residue (DFR) values is not minimal in comparison to the level of concern (i.e., the 

calculated MOE is not greater than 2 times higher than the level of concern, MOE = 170 

compared to the LOC of 100); therefore, EPA is requiring the 40CFR DFR data requirement to 

facilitate any necessary exposure assessments refinements and to further EPA’s general 

understanding of the availability of dislodgeable foliar pesticide residues.

2.2 Tolerance Considerations

2.2.1 Enforcement Analytical Method

Only parent flupyradifurone is considered a residue of concern for tolerance enforcement of 

plants and livestock commodities. 

An adequate analytical method (Method RV-001-P10-03) which uses high performance liquid 

chromatography with tandem mass spectrometry (HPLC/MS-MS) to quantitate residues of 

flupyradifurone in various crops is available for enforcement. The validated limit of 

quantification (LOQ) is 0.01 mg/kg for flupyradifurone in most commodities. 

An HPLC/MS/MS method, Method RV-004-A11-05 (latest revision of the data collection 

method RV-004-A11-04), is adequate as the enforcement method for determination of residues 

of flupyradifurone in livestock commodities The validated LOQ for flupyradifurone is 0.01 

mg/kg in all matrices
Page 8 of 116

FDA multiresidue methods (MRMs) are suitable for flupyradifurone only in non-fatty matrices.

The methods are not suitable for fatty matrices or matrices that require further clean-up. 

2.2.2 Recommended Tolerances

HED has reviewed the available residue data and has determined the appropriate tolerance levels 

for residues of flupyradifurone (Table 2.2.2). The recommended tolerance expression is as 

follows:

Tolerances are established for residues of the insecticide flupyradifurone, 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 flupyradifurone, 

4-[[(6-chloro-3-pyridinyl)methyl](2,2-difluoroethyl)amino]- 2(5H)-furanone.

Table 2.2.2. Tolerance Summary for Flupyradifurone

Commodity Proposed Tolerance 

(ppm)

HED-Recommended 

Tolerance (ppm)

Comments 

(correct commodity definition)

Aspirated grains 

fractions

40 40 Grain, aspirated grain fractions

Root vegetables except 

sugar beets (Crop 

Subgroup 1B)

1.5 0.9 Vegetable, root, except sugar 

beet, subgroup 1B

Tuberous and corm 

vegetables (Crop SubGroup 1C)

0.5 0.05 Vegetable, tuberous and corm, 

subgroup 1C

Crop subgroup 3-07A, 

onion, bulb, subgroup

0.3 0.09 Onion, bulb, subgroup 3-07A

Crop subgroup 3-07B, 

onion, green, subgroup

3 3.0 Onion, green, subgroup 3-07B

Leafy vegetable, except 

Brassica vegetables 

(Crop Group 4)

40 none Subgroup tolerances will be 

recommended.

Leafy greens, subgroup 

4A

- 30 The residue range among the 

representative crops exceeds the 

suggested 5X (6 – 7 X), but use of 

the highest representative crop 

(spinach) tolerance estimate is 

protective.

Leaf petioles, subgroup 

4B

- 9.0

Taro, leaves 40 30 Translation from subgroup 4A.

Head and Stem 

Brassica (Crop 

Subgroup 5A)

6 6.0 Brassica, head and stem, 

subgroup 5A

Leafy Brassica Greens 

(Crop Subgroup 5B)

40 40 Brassica, leafy greens, subgroup 

5B

Turnip greens 40 40 Translation from leafy Brassica 

greens
Page 9 of 116

Table 2.2.2. Tolerance Summary for Flupyradifurone

Commodity Proposed Tolerance 

(ppm)

HED-Recommended 

Tolerance (ppm)

Comments 

(correct commodity definition)

Edible-podded legume 

vegetables (Crop 

Subgroup 6A)

5 3.0 Vegetable, legume, edible 

podded, subgroup 6A

Succulent, Shelled Pea 

and Bean (Crop 

Subgroup 6B)

4 None The residue range between the 

representative crops exceeds the 

suggested 5X by a substantial 

amount, 13X. Crop-specific 

tolerances (pea, bean) are listed 

below.

Pea, succulent - 2.0 See 40CFR§180.1

Bean, succulent - 0.2 See 40CFR§180.1

Dried, shelled pea and 

bean (except soybean) 

(crop subgroups 6c)

6 3.0 Pea and bean, dried shelled, 

except soybean, subgroup 6C

Foliage of legume 

vegetables, including 

soybeans (Crop Group 

7, forage, green vines)

40 30 Vegetable, foliage of legume, 

group 7

Foliage of legume 

vegetables, including 

soybeans (Crop Group 

7), Hay

50 None Only one tolerance is possible 

per crop group. The 

recommended 30 ppm covers 

vines, forage, and hay from pea, 

bean, and soybean.

Soybean, seed 4 1.5

Fruiting vegetables, 

except cucurbits (Crop 

Group 8-10), fruit

3 1.5 Vegetable, fruiting, group 8-10

Tomato, paste 4 None Covered by the fruiting vegetable 

group tolerance.

Cucurbit vegetables 

(Crop Group 9), fruit

2 0.40 Vegetable, cucurbit, group 9

Citrus fruits (Crop 

Group 10-10), fruit

3 3.0 Fruit, citrus, group 10-10

Citrus, pulp, dried 15 10 Fruit, Citrus, dried pulp

Orange HAFT X Pf = 4.6 ppm X 

1.77 = 8.14 ppm

Pome fruits (Crop 

Group 11-10), fruit

1.5 0.70 Fruit, pome, group 11-10

Bushberry group (Crop 

Subgroup 13-07B), 

except cranberry

4 4.0 Bushberry, except cranberry,

subgroup 13-07B

Small fruit vine 

climbing subgroup, 

except fuzzy kiwifruit 

(Crop Subgroup 13-

07F)

3 3.0 Fruit, small vine climbing, except 

fuzzy kiwifruit, subgroup 13-07F

Grapes, raisin 6 5.0 Grape, raisin

Grape HAFT X Pf = 

1.90 ppm X 2.5 = 4.75 ppm
Page 10 of 116

Table 2.2.2. Tolerance Summary for Flupyradifurone

Commodity Proposed Tolerance 

(ppm)

HED-Recommended 

Tolerance (ppm)

Comments 

(correct commodity definition)

Low growing berry 

subgroup (Crop 

Subgroup 13-07G), 

except cranberry

1.5 1.5 Berry, low growing, except 

cranberry, subgroup 13-07G

Tree nuts (Crop Group 

14), nutmeat

0.15 0.02 Nut, tree, group 14-12

Pistachio 0.15 None Pistachio is included in the tree 

nut group 14-12.

Tree nuts (Crop Group 

14), hulls

15 15 Almond, hulls

Grain, cereal, group 15, 

except rice; grain

4 3.0 Grain, cereal, group 15, except 

rice and corn

Pop corn, grain - 0.05 Corn, pop, grain

Field corn, grain - 0.05 Corn, field, grain

Sweet corn, kernels 

plus cobs with husks 

removed (K+CWHR)

0.4 0.05 Corn, sweet, kernel plus cob with 

husks removed

Wheat, bran 5 None Wheat bran is covered by the 

cereal grain group 15 tolerance.

Rice, grain (rotational 

crop)

4 None No supporting data.

Grain, cereal, forage, 

fodder and straw, 

Group 16, forage 

20 30 Grain, cereal, forage, fodder and 

straw, group 16

Grain, cereal, forage, 

fodder and straw, 

Group 16, hay

40 None Only one tolerance is possible 

per crop group. The 

recommended 30 ppm covers hay, 

forage, fodder, straw, and stover 

of all cereal grains. The 

proposed 40 ppm for hay 

included residues from DFA, not 

part of the recommended 

definition.

Grain, cereal, forage, 

fodder and straw, 

Group 16, straw

30 None

Grain, cereal, forage, 

fodder and straw, 

Group 16, stover

15 None

Cotton, undelinted 

seed, Crop Subgroup 

20C

0.9 0.80 Cottonseed subgroup 20C

Cotton, gin by-products 40 40 Cotton, gin byproducts

Nongrass animal feeds, 

forage, Crop Group 18

20 None Inadequate number of trials for 

the representative commodity 

clover. Separate tolerances for 

clover with regional registration 

and alfalfa are listed elsewhere in 

this table. 

Alfalfa, forage - 9.0

Alfalfa, hay - 20

Nongrass animal feeds, 

hay, crop group 18

40 None Inadequate number of trials for 

the representative commodity 

clover. Separate tolerances for 

clover with regional registration 

and alfalfa are listed elsewhere in 

this table. 
Page 11 of 116

Table 2.2.2. Tolerance Summary for Flupyradifurone

Commodity Proposed Tolerance 

(ppm)

HED-Recommended 

Tolerance (ppm)

Comments 

(correct commodity definition)

Coffee, bean, green1 2 1.5 Coffee, green bean

Coffee, bean, roasted; 

instant

3 None Covered by the coffee bean 

tolerance.

Hops 20 10 Hop, dried cones

Peanut, hay 30 20

Peanut, nutmeat 0.15 0.04 Peanut

Prickly pear cactus, 

fruit

0.5 0.30 Cactus, fruit

Pitaya, fruit 0.5 0.30 Pitaya

Translation from prickly pear

cactus fruit.

Prickly pear cactus, 

pads

0.9 0.70 Cactus, pads

Cattle, fat 0.2 0.20

Cattle, meat 0.2 0.30

Cattle, meat byproducts 0.7 1.0

Goat, fat 0.2 0.20

Goat, meat 0.2 0.30

Goat, meat byproducts 0.7 1.0

Hog, fat 0.2 0.01

Hog, meat 0.2 0.01

Hog, meat byproducts 0.7 0.04

Horse, fat 0.2 0.20

Horse, meat 0.2 0.30

Horse, meat byproducts 0.7 1.0

Milk 0.3 0.15

Poultry, eggs 0.3 0.01 Egg

Poultry, meat 0.4 None No reasonable expectation of 

residues

Poultry, meat 

byproducts

0.5 None No reasonable expectation of 

residues

Sheep, fat 0.2 0.20

Sheep, meat 0.2 0.30

Sheep, meat byproducts 0.7 1.0

Tolerance with Regional Registration

Clover, forage - 20 Use limited to Oregon, Idaho, 

Washington 

Clover, hay - 30 Use limited to Oregon, Idaho, 

Washington

1 There is no US registration.

2.2.3 Revisions to Petitioned-For Tolerances

The Petitioner requested a definition for enforcement of tolerance as the sum of flupyradifurone 

and difluoro acetic acid (DFA) and 4-[(2,2-difluoroethyl)amino]furan-2(5H)-one (DFEAF), 

expressed as flupyradifurone, which significantly inflated the field trial residue values and 

resulted in higher tolerance values. EPA, consistent with its global review partners, has selected 
Page 12 of 116

parent flupyradifurone only as the residue definition for tolerance enforcement. Flupyradifurone 

is the major portion of the residue in plant commodities and in some livestock commodities. In 

other livestock commodities, it is present at the same approximate concentration as some 

metabolites. Moreover, the significant metabolite difluoroacetic acid (DFA) is not suitable for 

enforcement purposes, as its concentration is erratic with time. The harmonized enforcement 

definition, flupyradifurone only, will facilitate trade and is predicted to be the residue definition 

adopted by Codex in the future based on application of their policy. Therefore, EPA is reducing 

the tolerance values for the petitioned-for tolerances for the following commodity 

groups/subgroups or commodities: cattle, goat, hog, horse, and sheep meat and meat byproducts; 

hog fat; milk; poultry eggs; root vegetables subgroup 1B; tuberous and corm vegetables 

subgroup 1C; bulb onion subgroup 3-07A; leafy vegetable group 4; legume vegetables subgroup 

6A,6B,6C; soybean; foliage of legume vegetables group 7; fruiting vegetables group 8-10; 

cucurbit vegetables group 9; citrus pulp; pome fruits group 11-10; grape raisins; bushberry 

subgroup 13B except lowbush blueberry; tree nut group 14; cereal grain group 15 except rice 

and except corn; sweet corn, cereal grain forage, fodder, and straw group 16; nongrass animal 

feeds crop group 18; cotton undelinted seed; coffee bean; hops; peanut hay; peanut; prickly pear 

cactus fruit and pad.

The petition requested a tolerance for root vegetables, except sugar beets subgroup 1B at 1.5 

ppm. The ratio of highest average field trials (HAFTs) of the representative commodities 

(carrot/radish, 0.603/0.046 ppm) was 13, but the ratio of the median residue value was 1.8. The 

small median ratio indicates that the central tendency of both carrot and radish residue values are 

similar and that a single tolerance would be appropriate for the subgroup, represented by carrot 

and radish. The higher tolerance estimate from carrot (0.90 ppm) will cover all members of the 

subgroup. 

The petition requested a tolerance for the leafy vegetable, except brassica vegetables, group 4 at 

40 ppm. Based on the available residue data, EPA is establishing separate tolerances for each of 

the subgroups of group 4, instead of a single tolerance for the whole group. For subgroup 4A 

(leafy greens), EPA is establishing a tolerance at 30 ppm, based on the highest residues, which 

were found on the representative crop spinach. For subgroup 4B (leafy petioles), EPA is 

establishing a separate tolerance at 9.0 ppm based on the celery residues. The leafy greens 

subgroup tolerance was translated to cover taro leaves; therefore, EPA is establishing a tolerance 

for taro leaves at 30 ppm, rather than the 40 ppm requested. 

The petitioned-for tolerance for the shelled pea and bean subgroup 6B at 4 ppm was not possible 

because the residues on the garden pea and lima bean were substantially different. Residues 

differ by more than 5X between succulent peas and succulent beans. In accordance with 40 CFR 

180.40(g), a subgroup tolerance is not normally appropriate; rather, EPA may establish 

individual crop tolerances. Therefore, EPA is establishing individual tolerances for succulent 

peas and succulent beans. 

The petition requested a tolerance for cereal grains, grain, group 15 except rice at 4 ppm. The 

residues on sweet corn and field corn grain were much lower than those on sorghum, wheat, and 

barley grains; therefore, EPA is excluding corn (field corn, popcorn, and sweet corn) grain from 

that group 15 tolerance, as well as rice. Based on available residue data, EPA is establishing 
Page 13 of 116

separate tolerances for popcorn, grain, field corn, grain, and sweet corn (kernels plus cobs with 

husks removed) at 0.05 ppm. Under 180.40(h), EPA may exclude some commodities from a 

group tolerance where the residue levels are significantly higher or lower than the other 

commodities in the group. Corn, unlike the other cereal grains, has a protective husk and this 

difference is often reflected in lower residues for late season foliar applications. Therefore, EPA 

is excluding corn grain and rice from the crop group 15 tolerance and establishing separate 

tolerances for corn. The remaining cereal grains, represented by grain sorghum, barley, and 

wheat, are quite similar.

The petition requested a tolerance on nongrass animal feeds group 18, forage at 20 ppm and hay 

at 40 ppm. EPA is unable to establish group 18 tolerances at this time for forage and hay 

because data from only four field trials on clover (one of the representative crops) were 

available. Based on the available data, EPA is establishing tolerances for alfalfa and regional 

tolerances for clover (since use on clover is restricted to Washington, Oregon, and Idaho, the 

area where the field trials were conducted). A group tolerance could be considered if additional 

field trials for clover from diverse areas of the US were supplied.

The petition requested a tolerance for rice grain at 4 ppm as a rotational crop. EPA cannot 

establish this tolerance at this time because no data were provided to support this request. Rice 

field trial data are required to establish a tolerance. 

The proposed wheat bran tolerance of 5 ppm is not necessary. The cereal grain group tolerance 

covers wheat bran. The highest average field trial (HAFT) residue for wheat grain was 0.73 ppm 

and the experimentally determined processing factor for the conversion of grain to bran was 2.4. 

Therefore, the tolerance estimate for wheat bran is 1.8 ppm (0.73 X 2.4). As 1.8 ppm is less than 

the 3 ppm cereal group tolerance, a separate tolerance for wheat bran is not needed. 

EPA was petitioned for tolerances on tree nut group 14 and pistachio. In the Federal Register of 

August 22, 2012 (77 FR 50617) (FRL–9354–3), EPA issued a final rule that revised the crop 

grouping regulations. As part of this action, EPA expanded and revised the existing tree nut 

group 14. Changes to crop group 14 included adding the specialty commodities African nut tree, 

Brazilian pine, Bunya, Bur oak, Cajou nut, Candlenut, Coconut, Coquito nut, Dika nut, 

Ginkgo, Guiana chestnut, Heartnut, Japanese horse-chestnut, Mongongo nut, Monkey-pot, 

Monkey puzzle nut, Okari nut, Pachira nut, Peach palm nut, Pequi, Pili nut, Pine nut, Pistachio, 

Tropical almond and Yellowhorn including cultivars, varieties, and/or hybrids of these; and 

naming the new crop group tree nut group 14–12. EPA indicated in the August 22, 2012 final 

rule as well as the earlier November 9, 2011 proposed rule (76 FR 69693) (FRL–8887–8) that, 

for petitions for which a Notice of Filing had been published, the Agency would attempt to 

conform these petitions to the rule. Therefore, consistent with this rule, EPA has assessed 

exposure to the, insecticide flupyradifurone, assuming use under the revised tree nut group 14-

12. Because revising the requested crop group to the updated crop group did not result in a risk 

of concern, EPA is establishing tolerances for flupyradifurone residues on tree nut group 14–12. 

Cranberry was removed from subgroups 13-07B and 13-07G at the request of the petitioner as a 

modification to the original request. 
Page 14 of 116

Tolerances are not needed for the processed commodities tomato paste, roasted coffee, and 

instant coffee. The recommended tolerances for the raw agricultural commodities, tomato and 

green coffee bean cover the respective processed commodities. The highest average field trial 

(HAFT) result for coffee was 0.55 ppm, and the processing factors for roasted coffee and instant 

coffee were 0.59 and 1.9, respectively. Tolerance estimate (HAFT X processing factor; 

0.55X0.59 = 0.32 ppm roasted bean; 0.55X1.9=1.0 ppm instant coffee) are less than the 

recommended green coffee bean tolerance (1.5 ppm). The HAFT for the tomato field trials was 

0.57 ppm and the processing factor for conversion to paste was 2.0, and the product (0.57X2.0) 

is less than the recommended fruiting vegetable group tolerance (1.5 ppm).

Tolerances are not required for poultry meat and poultry meat byproducts, as the projected diet 

for poultry and the results of the poultry feeding study indicate that residues are not likely in 

poultry meat and poultry meat byproducts.

2.2.4 International Harmonization

Flupyradifurone has not been considered by the Codex system, and therefore there are no 

harmonization issues. The active global review participants, Australia, Canada, and the US, are 

working together to harmonize MRLs wherever possible. All plant commodity tolerances are 

harmonized. The livestock commodity tolerances for ruminant commodities are not harmonized 

with Canada, with US tolerance being approximately twice the corresponding Canadian 

tolerances. This is a direct result of the different diets (exposures) determined by Canada and the 

US. Canada does not consider forage and fodder crops that are not native to Canada. The US 

and Canada tolerances for eggs are harmonized. Canada will establish default tolerances for 

poultry meat and meat by-products at the LOQ. The US will establish no poultry tolerances as 

there is no reasonable expectation of residues. A comparison of specific tolerances/MRLs is 

provided in HED’s summary of flupyradifurone residue data (S. Funk, 02/17/2014, D415670).

2.3 Label Recommendations

2.3.1 Recommendations from Residue Reviews

The proposed label pre-harvest interval (PHI) for prickly pear is 14 days, but the crop trials were 

conducted with a 21- day PHI. The label PHI must be changed to 21 days. 

The proposed label specifies use on members of the non-grass animal feeds crop group 18 with 

use on clover limited to Washington, Idaho, and Oregon. However, clover and alfalfa are the 

representative commodities of this group, and there are an inadequate number of clover trials. 

Therefore, the label must be amended to allow use on alfalfa (nationally) and clover in 

Washington, Idaho, and Oregon. Uses on crop group 18 must be removed from the label.

A rotational crop interval of 30 days for rice is not adequately supported. The rotational field 

trials conducted in Europe at 50% of the seasonal rate shows no residues on barley grain at a 30 

day PBI. However, the residue level at a 100% seasonal rate cannot be predicted. Since the use 

on rice is not supported by adequate rotational crop data and cereal grain primary trials cannot be 

used to establish a rice tolerance (see 2.2.3), rice falls under the crops not on the label and for 
Page 15 of 116

which no tolerances exist; therefore, the appropriate interval is 12-months. The exception for 

rice must be removed from the label.

The label must be amended to indicate that uses in greenhouses are not allowed because 

supporting field trial studies for greenhouse uses were not submitted.

The proposed label specifies use on members of crop subgroup 1B (root vegetables). However, 

a crop subgroup tolerance could not be recommended. Therefore, the label must be amended to 

indicate use on carrot and radish only.

3.0 Introduction

Flupyradifurone is a member of the butenolide class of chemistry effective against a broad range 

of sucking insects. It has a similar insecticidal mode of action to neonicotinoids. 

Flupyradifurone is formulated into two systemic insecticide products: Sivanto 200 SL is for soil 

and foliar applications intended for the control of aphids, whiteflies, leafhoppers and other 

insects infesting many fruit, vegetable, plantation, row and specialty crops; and BYI 02960 480 

FS is for soybean seed treatment. After uptake into the plant via the roots or translaminarly 

through leaf tissue, flupyradifurone is translocated acropetally in the xylem, in the direction of 

the transpiration stream and is distributed into plant cells.

3.1 Chemical Identity

Table 3.1. Flupyradifurone Nomenclature.

Compound

C12H11ClF2N2O2

Chemical Structure

Common name Flupyradifurone

Company experimental name BYI 02960

IUPAC name 4-[(6-chloro-3-pyridylmethyl)(2,2-difluoroethyl)amino]furan-2(5H)-one

CAS name 4-[[(6-chloro-3-pyridinyl)methyl](2,2-difluoroethyl)amino]- 2(5H)-furanone

CAS # 951659-40-8

End-use product/EP SivantoTM 200SL (1.67 lbs ai/gallon or 200 g ai/l soluble concentrate)

BYI 02960 480 FS (4 lbs ai/gallon or 480 g ai/l flowable concentrate for seed 

treatment)

3.2 Physical/Chemical Characteristics

Flupyradifurone has substantial solubility in both organic solvents and water and a low 

octanol/water partition coefficient, and therefore is predicted to show no strong preference for fat 

O

Cl N

N

F

F

O
Page 16 of 116

versus muscle or for cream versus skim milk/whey. It has a low vapor pressure and not expected 

to volatilize. 

3.3 Pesticide Use Pattern

Table 3.3.1. Proposed Use Pattern for Flupyradifurone

Applic. Type

Applic. 

Rate 

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and 

Limitations

BYI 02960 480 FS (4 lbs ai/gallon)

Soybean

Seed treatment

0.045 –

0.068 

mg 

ai/seed,

30 – 45 g

ai/100 

kg,

or 0.0271

1

0.365

(from uses, 

seed 

treatment 

and foliar)

N/A

Use only as a commercial 

water-based slurry. All 

seeds treated must be 

colored with an EPAapproved dye or colorant. 

Treated seeds must be 

labeled in accordance with 

the requirements of the 

Federal Seed Act.

SivantoTM 200 SL (1.67 lbs ai/gallon)

Cereal Grains (except rice)

Foliar 0.183 - 0.365

7 sweet corn

7 forage

21 grain

21 straw

21 stover

Minimum retreatment 

interval 7 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Cotton

Foliar 0.183 - 0.365 14

Minimum retreatment 

interval 10 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Non-Grass Animal Feeds (Crop Group 18 including alfalfa, clover, crown vetch, kudzu, lespedeza, lupin, milk 

vetch, sainfoin, trefoil, velvet bean, vetch)

Foliar 0.183 - 0.365

7 forage, 

silage, hay, 

or seed of 

alfalfa, 

lespedeza, 

sainfoin

14 all other

Minimum retreatment 

interval 10 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial. Use on clover is 

limited to Idaho, 

Washington, and Oregon.

Peanut

Foliar 0.183 - 0.365 7

Minimum retreatment 

interval 10 days. Minimum 

spray volume 10 

gallons/acre for ground 
Page 17 of 116

Table 3.3.1. Proposed Use Pattern for Flupyradifurone

Applic. Type

Applic. 

Rate 

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and 

Limitations

and 2 gallons/acre for 

aerial.

Root Vegetables (except sugar beet) (crop group 1B including garden beet, carrot, celeriac, chervil, chicory, 

ginseng, horseradish, parsley (turnip-rooted), radish, oriental radish, rutabaga, salsify, skirret, turnip)

Foliar 0.183 - 0.365 7

Minimum retreatment 

interval 10 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Tuberous and Corm Vegetables (crop group 1C including Arracacha, Arrowroot, Artichoke (Chinese and 

Jerusalem), Canna (edible), Cassava (bitter and sweet), Chayote (root), Chufa, Dasheen (taro), Ginger, Leren, 

Potato, Sweet potato, Tanier (cocoyam), Turmeric, Yam bean (jicama, manoic pea), Yam (true)

Foliar 0.183 - 0.365 7

Minimum retreatment 

interval 7 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Leafy Vegetables (except Brassica) (crop group 4 including Amaranth (leafy amaranth, Chinese spinach, 

tampala), Arugula (Roquette), Cardoon, Celery, Celtuce, Chervil, Chinese celery, Chrysanthemum (edibleleaved and garland), Corn salad, Cress (garden), Cress (upland, yellow rocket, winter cress), Dandelion, Dock 

(sorrel), Endive, Florence fennel (sweet anise, sweet fennel, Finocchio), Lettuce (head and leaf), Orach, Parsley, 

Purslane (garden and winter), Radicchio (red chicory), Rhubarb, Spinach [including New Zealand and vine

(Malabar spinach, Indian spinach)], Swiss chard, Taro leaves

Foliar 0.183 - 0.365 1

Minimum retreatment 

interval 7 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Brassica (Cole) Leafy Vegetables (crop group 5 including Broccoli, Broccoli Raab (rapini), Brussels sprouts, 

Cabbage, Cauliflower, Cavalo broccolo, Chinese broccoli (gai lon), Chinese cabbage (bok choy), Chinese 

cabbage (napa), Chinese mustard cabbage (gai choy), Collards, Kale, Kohlrabi, Mizuna, Mustard greens, 

Mustard spinach, Rape greens) and Turnip Greens

Foliar 0.183 - 0.365 1

Minimum retreatment 

interval 7 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Legume Vegetables (succulent or dried) (crop group 6 including Edible Podded and Succulent Shelled Pea and 

Bean and Dried Shelled Pea and Bean (Lupinus spp., including grain lupin, sweet lupin, white lupin, and white 

sweet lupin) Bean (Phaseolus spp., including field bean, kidney bean, lima bean, navy bean, pinto bean, runner 

bean, snap bean, tepary bean, wax bean) Bean (Vigna spp., including adzuki bean, asparagus bean, blackeyed 

pea, catjang, Chinese longbean, cowpea, Crowder pea, moth bean, mung bean, rice bean, Southern pea, urd bean, 

yardlong bean) Pea (Pisum spp. including dwarf pea, edible-pod pea, English pea, field pea, garden pea, green 

pea, snow pea, sugar snap pea) Other Beans and Peas (Broad bean (fava bean), Chickpea (garbanzo bean), Guar, 

Jackbean, Lablab bean (hyacinth bean), Lentil, Pigeon pea, soybean (immature seed), Sword bean, soybean)
Page 18 of 116

Table 3.3.1. Proposed Use Pattern for Flupyradifurone

Applic. Type

Applic. 

Rate 

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and 

Limitations

Foliar 0.183 - 0.365

7 forage

7 leaves

7 vines

7 pods

7 hay

7 seed (fresh 

or dry, except 

soybean)

21 dry 

soybean seed

Minimum retreatment 

interval 7 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Fruiting Vegetables (crop group 8-10 including Cocona, Eggplant (including: African, Pea and Scarlet 

eggplants), Garden huckleberry, Goji berry, Groundcherry, Martynia, Naranjilla, Okra, Pepino, Pepper 

(including all peppers i.e. bell, non-bell, hot, sweet, etc.), Roselle, Sunberry, Tomatillo, Tomato (including: 

Bush, Currant, Tree) including cultivars, varieties and/or hybrids of these commodities)

Foliar 0.183 -

0.365

1

Minimum retreatment 

interval 10 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Soil 0.365 1 45

The following methods of 

application may be used: 

1. chemigation into rootzone through low-pressure 

drip, trickle, microsprinkler or equivalent 

equipment;

2. injection below the 

eventual seed-line prior to 

planting. Place pesticide 3-

4 inches below seed-line;

3. potting hole drench at 

transplanting; or

4. post-transplant drench 

following setting and 

covering.

Cucurbit Vegetables (crop group 8 including Chayote (fruit), Chinese waxgourd (Chinese preserving melon), 

Citron melon, Cucumber, Gherkin, Gourd (edible, includes hyotan, cucuzza, hechima, Chinese okra), 

Momordica spp. (includes balsam apple, balsam pear, bitter melon, Chinese cucumber), Muskmelon (hybrids 

and/or cultivars of Cucumis melo including true cantaloupe, cantaloupe, casaba, Crenshaw melon, golden 

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

melon, snake melon), Pumpkin, Squash (includes summer squash types such as: crookneck squash, scallop 

squash, straightneck squash, vegetable marrow, zucchini, and winter squash types such as acorn squash, 

butternut squash, calabaza, cushaw, Hubbard squash, spaghetti squash), Watermelon (includes hybrids and/or 

varieties of Citrullus lanatus)

Foliar 0.183 - 0.365 1

Minimum retreatment 

interval 7 days. Minimum 

spray volume 10 

gallons/acre for ground 
Page 19 of 116

Table 3.3.1. Proposed Use Pattern for Flupyradifurone

Applic. Type

Applic. 

Rate 

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and 

Limitations

and 2 gallons/acre for 

aerial.

Soil 0.365 1 21

The following methods of 

application may be used: 

1. chemigation into rootzone through low-pressure 

drip, trickle, microsprinkler or equivalent 

equipment;

2. injection below the 

eventual seed-line prior to 

planting. Place pesticide 3-

4 inches below seed-line;

3. potting hole drench at 

transplanting; or

4. post-transplant drench 

following setting and 

covering.

Hops

Foliar 0.137 1 0.137 21

Minimum spray volume 

25gallons/acre for ground 

and 10gallons/acre for 

aerial.

Citrus Fruit (crop group 10-10 including Calamondin, Citrus citron, Citrus hybrids (Citrus spp., Eremocitrus 

spp., Fortunella spp., Microcitrus spp., and Poncirus spp.), Grapefruit (including Japanese summer), Kumquat, 

Lemon, Lime, Lime (Sweet, Australian desert, Australian finger, Australian round, Brown River finger, Mount 

White, New Guinea wild, Russell River, Tahiti), Mandarin (Mediterranean, Satsuma), Orange (sour, sweet, 

Tachibana, Trifoliate), Pummelo, Tangelo, Tangerine [includes Tangerine (mandarin or mandarin orange), 

Clementine, Mediterranean mandarin, Satsuma mandarin, Tangelo, Tangor, cultivars and varieties], Tangor,

Uniq fruit, and cultivars, varieties and/or hybrids of these commodities).

Foliar 0.183 -

0.365

1

Minimum retreatment 

interval 10 days. Minimum 

spray volume 2.5 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.2

Soil 0.365 1 30

Pesticide may be applied 

by the following methods:

1. chemigation into rootzone through low-pressure 

drip, trickle, microsprinkler or equivalent 

equipment; or

2. basal drench in 

sufficient water to move 

pesticide into root-zone.

Pome Fruit (crop group 11-10 including Apple, Azarole, Crabapples (Chinese apple, Chinese crab apple, 

Chinese flowering apple, Crab apple, Cutleaf crab apple, Florentine crab apple, Hall crab apple, Iowa crab apple, 

Japanese crab apple, Kai do crab apple, Manchurian crab apple, Paradise apple, Sargent's crab apple, Siberian 
Page 20 of 116

Table 3.3.1. Proposed Use Pattern for Flupyradifurone

Applic. Type

Applic. 

Rate 

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and 

Limitations

crab apple, Soulard crab apple, Southern crab apple, Sweetcrab apple, Tea crab apple, Toringa crab apple, 

Western Crabapple, Yunnan crab apple, and varieties and/or hybrids of these), Loquat, Mayhaw, Medlar, Pear, 

Asian pear, Quince, Chinese quince, Japanese quince, Tejocote, and cultivars, varieties and/or hybrids of these).

Foliar 0.183 - 0.365 14

Minimum retreatment 

interval 10 days. Minimum 

spray volume 25 

gallons/acre for ground 

and 10 gallons/acre for 

aerial.

Bush Berry (crop subgroup 13-07B, except cranberry, including Aronia berry, Blueberry (Vaccinium spp. –

highbush, lowbush and cultivars and/or hybrids of these [= all blueberry species]), Chilean guava, Currant 

(black, buffalo, native and red), Elderberry, European barberry, Gooseberry (Ribes spp.), Honeysuckle (edible), 

Huckleberry, Jostaberry, Juneberry, Lingonberry, Salal, Sea buckthorn, and cultivars, varieties and/or hybrids of 

these).

Foliar 0.183 - 0.365 3

Minimum retreatment 

interval 7 days. Minimum 

spray volume 25 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Low Growing Berry (crop subgroup 13-07G, except cranberry, including Bearberry, Bilberry, Blueberry 

(lowbush), Cloudberry, Lingonberry, Muntries, Partridgeberry, Strawberry, plus cultivars, varieties and/or 

hybrids of these.)

Foliar 0.183 - 0.365 0

Minimum retreatment 

interval 10 days. Minimum 

spray volume 10 

gallons/acre for ground 

and 2 gallons/acre for 

aerial.

Small Fruit Vine Climbing (except Fuzzy Kiwifruit) (crop subgroup 13-07F including Amur river grape, 

Gooseberry (Ribes spp.), Grape, Kiwifruit (hardy, only), Maypop, Schisandra berry, and cultivars, varieties 

and/or hybrids of these

Foliar 0.183 -

0.365

0

Minimum retreatment 

interval 10 days. Minimum 

spray volume 25 

gallons/acre for ground 

and 10 gallons/acre for 

aerial.

Soil 0.365 1 30

Pesticide may be applied 

by the following methods:

1. chemigation into rootzone through low-pressure 

drip, trickle, microsprinkler or equivalent 

equipment; or

2. basal drench in 

sufficient water to move 

pesticide into root-zone.
Page 21 of 116

Table 3.3.1. Proposed Use Pattern for Flupyradifurone

Applic. Type

Applic. 

Rate 

(lb ai/A)

Max. 

No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. Rate

(lb ai/A)

PHI

(days)

Use Directions and 

Limitations

Tree Nut (crop group 14 including Beech nut, Brazil nut, Butternut, Cashew, Chestnut, Chinquapin, Hazelnut

(filbert), Hickory nut, Macadamia nut (bush nut), Pecan, Pistachio, Walnut [including black and English 

(Persian) walnuts]), excluding almond.

Foliar 0.183 - 0.365 7

Minimum retreatment 

interval 14 days. Minimum 

spray volume 75 

gallons/acre for ground. 

Do NOT apply by aerial 

application.

Cotton

Foliar 0.183 - 0.365 14

Minimum retreatment 

interval 10 days. Minimum 

spray volume 10 

gallons/acre for ground, 2 

gallons/acre for aerial. 

Prickly Pear /Cactus Pear (opuntia spp.), Pitaya

Foliar 0.183 - 0.365 14

Minimum retreatment 

interval 7 days. Minimum 

spray volume 75 

gallons/acre for ground. 

Do NOT apply by aerial 

application.

Coffee Beans (Import from Central America (Guatemala, Mexico) and Brazil)3

Drench + Foliar

0.535

+

0.178

1

+ 

3

1.07 0

The minimum retreatment 

interval for foliar 

application is 15 days. 

Application to soil should 

be October to February, 

when the soil is the 

wettest. 

Rotational Crops

Crop Type Rotational Interval (days)

On-label 0

With tolerance4 0

Sugarcane

(Florida) 14

Rice (white and wild) 30

All others 360

1 For a seeding rate of 60 lbs/acre (ExpoSAC SOP15, 03/02/2004)

2 Minimum application volumes are for control of Asian citrus psyllid control in Florida only. For control or suppression of other pests, 

application volumes should be increased to provide thorough and complete coverage to obtain adequate control.

3 Requisite translated label from Brazil was provided (MRID 48844205)

4Crop Group 3 has a recommended tolerance, but not a use on the proposed label.

3.4 Anticipated Exposure Pathways

Humans may be exposed to flupyradifurone in food and drinking water since flupyradifurone 

may be applied directly to growing crops and application may result in flupyradifurone reaching 
Page 22 of 116

surface and ground sources of drinking water. In an occupational setting, applicators may be 

exposed while handling the pesticide prior to application, during seed treatment, as well as 

during application. There is also a potential for post-application exposure for workers reentering treated fields. 

This is the first risk assessment prepared for the proposed uses of flupyradifurone. This risk 

assessment considers all of the exposure pathways based on the proposed new uses of 

flupyradifurone.

3.5 Consideration of Environmental Justice

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.epa.gov/environmentaljustice/resources/policy/exec_order_12898.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 U.S. Department of 

Agriculture’s National Health and Nutrition Examination Survey, What We Eat in America, 

(NHANES/WWEIA) 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 and ethnic 

group. 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 children 1-2 years, youths, and adults entering or playing on treated 

areas post-application 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.

4.0 Hazard Characterization and Dose-Response Assessment

Flupyradifurone is a member of the butenolide class of chemicals, which the Registrant claims to 

have a pesticidal mode of action similar to neonicotinoids, acting on the nicotinic acetylcholine 

receptor (nAchR). Analogous to neonicotinoids, flupyradifurone is thought to bind and stimulate 

insect nAchRs, leading to paralysis and death. The effects seen in the acute neurotoxicity study 

are likely related to stimulation of the nAchRs, however there is limited additional evidence in 

mammalian studies that the pesticidal mode of action is important to mammals. 

4.1 Toxicology Studies Available for Analysis

All the required toxicity studies on flupyradifurone have been submitted to support proposed 

food-use registrations. The toxicology database is acceptable for characterizing flupyradifurone 

hazard and includes 28-day oral, 90-day oral, and 28-day dermal studies in rats; 28-day oral and 
Page 23 of 116

90-day oral toxicity studies in mice; 28-day-oral and 90-day oral toxicity studies in dogs; a 1-

year dietary study in dogs; a carcinogenicity study in mice; a 2-year dietary combined 

chronic/carcinogenicity in rats; developmental toxicity studies in rats and rabbits; a 2-generation 

reproduction study in rats; acute and subchronic neurotoxicity studies in rats; a developmental 

neurotoxicity study in rats; mutagenicity and genotoxicity studies in bacterial & mammalian 

model systems; 28-day dietary immunotoxicity studies in rats; metabolism and pharmacokinetic 

studies in rats with 3 different 14C- labeling positions on flupyradifurone; and in vivo and in vitro

dermal penetration studies on the formulated flupyradifurone. Of the available studies, some 

subchronic toxicity studies in rats, mice, and dogs contained data on liver enzymes, thyroid 

hormones, and plasma concentration of flupyradifurone. Two metabolites (DFA and 

difluoroethyl-amino-furanone) were tested in subchronic oral toxicity studies and in the 

genotoxicity battery of studies, while two other metabolites ((6-chloro-3-pyridyl) methanol and 

6-chloronicotinic acid (6-CNA)) were tested only with bacterial gene mutation assays. 

Summaries of all toxicology studies are presented in Attachment A.

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

Absorption, distribution, metabolism and elimination (ADME) of flupyradifurone were 

investigated using 14C label at three different positions as shown below. 

Pyridinylmethyl14C Furanone-4-

14C Ethyl-1-14C

Regardless of labeling position, the results showed that following oral administration of a low 

dose (2 mg/kg) of flupyradifurone to male and female rats, the gastrointestinal absorption of 

radioactivity was high and accounted for >80 % of the administered dose. In most cases, the 

maximum plasma concentration was reached within 1 or 2 hours after dosing. With the high 

dose (200 mg/kg), the peak plasma concentration was observed between 2 and 4 hours after 

dosing. After reaching the peak concentration, the radioactivity levels in plasma declined 

steadily by several orders of magnitude in all studies independent of sex or labeling position of 

the test compound. Elimination was very fast, mainly via urine and almost completed after 24 

hours. No radioactivity was detected in the expired air after dosing with the pyridinylmethyland ethyl-1-labeled compounds. With administration of [furanone-4-

14C] flupyradifurone 

between 1 and 3% of the administered radioactivity was detected in the expired air.

The absorbed dose was rapidly distributed; at approximately 1 hour after dosing, the 

concentrations in liver and kidney were significantly higher than in blood, suggesting a preferred 

clearance from blood and distribution mainly to the organs responsible for metabolism (liver) 

and excretion (kidney). Very low levels were found in the brain, spinal cord, and renal fat. 

O

Cl N

N

F

F

O

*

O

Cl N

N

F

F

O

*

O

Cl N

N

F

F

O

*
Page 24 of 116

These results are similar in male and female rats independent of the labeling position. A fast 

decline of radioactivity concentrations was observed for all organs and tissues in males and 

females during the entire test period. Concentrations fell for most organs and tissues below 5% 

of the maximum tissue radioactivity after one day. After seven days, only very low 

concentrations were found in a few organs and tissues of rats. Basically, male and female rats 

exhibited very similar absorption, distribution, and elimination patterns. The quantitative whole 

body autoradiography studies demonstrated that there was no accumulation of radioactivity in 

any organ of the tested male and female rats. 

Flupyradifurone was readily metabolized in the rat. Numerous metabolites were formed, most of 

them being minor. The parent compound represented the predominant part of the radioactivity in 

urine of male and female rats. In feces of male rats, the metabolite BYI 02960-OH was more 

prominent than the parent compound. Two metabolites, 6-chloro-nicotinic acid (BYI 02960-6-

CNA) and BYI 02960-hippuric acid were also prominent in male but not in female rats.

The organ metabolism study using the ethyl-1-

14C label showed that, in the 24 hours samples of 

plasma, organs, and tissues, difluoroacetic acid (BYI 02960-DFA) was by far the major

metabolite accounting for more than 50% of the radioactivity in the tissues. However, the BYI 

02960-DFA accounted for approximately 6% of the administered dose. 

The metabolic profiles in urine and feces were very similar for both sexes, but male rats showed 

a higher rate of metabolite formation as compared to females.

The figure below schematically shows the sites of the molecule which are involved in the 

metabolic reactions: 

The principal metabolic reactions of flupyradifurone in rats could be summarized as follows:

 Hydroxylation followed by conjugation with glucuronic acid or sulfate;

 Cleavage of the difluoroethyl group forming BYI 02960-des-difluoroethyl, and BYI 02960-

DFA;

 Cleavage of the molecule at the pyridinylmethylene bridge forming 6-chlor-nicotinic acid 

BYI 02960-6-CNA, which was further conjugated with glycine to BYI 02960-hippuric acid 

and BYI 02960-difluoroethyl-amino-furanone.

O

N

N

F

F

Cl

O

hydroxylation and

conjugation

cleavage

cleavage
Page 25 of 116

4.2.1 Dermal Absorption

There is no dermal absorption study available with technical grade flupyradifurone. However, in 

vivo (rat) and in vitro (human and rat skin) dermal penetration studies with the liquid (SC) 

formulation of flupyradifurone are available. The dermal absorption values from the 24 hour 

measurements from in vivo and in vitro dermal absorption studies on the most dilute test 

formulation (0.1 g/L of 200 g/L SL) were used to estimate the human dermal absorption factor 

(DAF) with the equation: human DAF = (in vitro human % absorption) x [(in vivo rat % 

absorption/ (in vitro rat % absorption)]. The calculated DAF was 7.42% for 24-hour exposure. 

4.3 Toxicological Effects

The most sensitive effects seen in the flupyradifurone database were skeletal muscle 

atrophy/degeneration in dogs, which appear to be the most sensitive tested animal; however, with 

3⁄4 body weight scaling (Appendix A.5) the rat and dogs are equally as sensitive to the effects of 

flupyradifurone . With dietary administration, reductions in body weight and food consumption 

were commonly seen in all species of the test animals (rats, mice, dogs, and rabbits). The liver 

and thyroid were also common targets of flupyradifurone toxicity. The liver effects often 

consisted of increased liver weight, hepatocellular hypertrophy, liver enzyme increases 

(cytochrome p450 increases), and decreases in total cholesterol. Some of the liver effects were 

judged to be adaptive responses while some were correlated with vacuolations and changes in 

clinical chemistry parameters (increases in alkaline phosphatase (ALP) and alanine 

aminotranspherase (ALT), and cholesterol level changes indicative of liver effects which were 

progressed beyond the adaptive stage. The thyroid effects consisted of thyroid follicular cell 

hypertrophy and were seen mainly in rats. In addition, the thyroid effects were generally found 

in conjunction with liver effects. 

The developmental toxicity data in rats and rabbits showed that flupyradifurone caused delayed 

bone ossification in the fetal rats and increase incidence of fetal death in rabbits. These effects 

were seen at the maternal lowest observed adverse effect levels (LOAEL, 150 mg/kg/day) in rat 

developmental study. No adverse maternal effects was seen at the highest tested dose (80 

mg/kg/day) in the combined data of rabbit developmental studies (main and range finding 

studies). The increased incidence of fetal death in rabbits was considered to be both a 

quantitative increase in susceptibility in the developing fetuses. However, clear no observed 

adverse effect levels (NOAELs) were established for both rat and rabbit developmental toxicity 

studies.

The results of a 2-generation reproduction study showed that flupyradifurone reduced the

number of estrus cycles, decreasing the number of implantations in P2 dams, and decreasing the

litter size in the presence of decreased body weight and food consumption in maternal animals.

In addition, the body weight of F2 pups was decreased at a dose (37.8 mg/kg/day) where no 

effect was seen in the parental animals, and this finding suggested a quantitative increase in 

susceptibility in the young rat. 
Page 26 of 116

Carcinogenicity studies in rats and mice did not yield a compound-related increase in tumor 

incidence, and the genotoxicity battery did not show flupyradifurone to produce any 

genotoxicity. 

The acute neurotoxicity study showed that flupyradifurone caused increases in the incidence of 

piloerection and dilated pupils at 50 mg/kg. At the next higher dose level (200 mg/kg) and 

above, it produced a large number of clinical signs, which are indicative of neurotoxicity. These 

included lower muscle tone, rapid respiration, low arousal, tremors, myoclonic jerks, chewing, 

repetitive licking of lips, gait incoordination, flattened or hunched posture, dilated pupils, 

impaired (uncoordinated or slow) righting reflex, impaired flexor and tail pinch responses and 

reduced rectal temperature. However, none of these clinical signs were found in the dietary 

feeding studies, including the 90-day neurotoxicity study. The effects seen in the acute 

neurotoxicity study are likely related to stimulation of the nAchRs, however there is limited 

additional evidence in mammalian studies that the pesticidal mode of action is important to 

mammals. The differences in the findings between the acute neurotoxicity study and other 

studies using dietary administration might be explained by the rapid absorption and excretion. 

Flupyradifurone was absorbed rapidly in the metabolism study where rats were dosed by gavage. 

Peak plasma levels were reached within 1-4 hours of dosing depending on the dose, and 

flupyradifurone was almost completely eliminated approximately 24 hours after administration. 

With dietary administration, the rodent test animal consumed the compound mostly during the 

entire night, and the internal flupyradifurone concentration required to produce the effect was 

probably seldom reached due to metabolism and rapid elimination from the body. As a result, 

clinical signs were not reported. No neurotoxicity or other adverse effects were seen in 90-day 

dietary neurotoxicity study in rats at dose levels as high as 174 mg/kg/day.

No immunotoxicity was found in rats tested at the highest dose of 230 mg/kg/day.

The acute toxicity of flupyradifurone was low for all routes (oral, dermal, and inhalation). The 

rat oral LD50 was estimated to be greater than 2,000 mg/kg, with mortalities reported at 2,000 

mg/kg but none at 300 mg/kg (Toxicity Category III). The acute dermal LD50 for rats was 

>2,000 mg/kg (Toxicity Category III). The acute inhalation LC50 for rats was >4,671 mg/m3

(4.67 mg/L), which was the highest achievable concentration (Toxicity Category IV). 

Flupyradifurone was not irritating to rabbit skin and caused only slight ocular irritation (redness 

of the conjunctivae) which was reversed within 48 hours.

Several metabolites were found in plants and rat metabolism studies; some of these metabolites 

were tested in mutagenicity studies and subchronic oral toxicity studies. The results showed that 

most of the flupyradifurone metabolites had lower toxicity than the parent compound except 

difluoroacetic acid (DFA) (BCS-AA56716 see Toxicity Profile Table in Attachment A). The 

limited data (90-day oral feeding study in rats) showed that DFA produced a different effect 

from the parent compound, black foci in the glandular part of the stomach which correlated with 

the histopathology finding of focal glandular erosion/necrosis. In addition, slight decreases in 

hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin, and hematocrit were also 

found. The stomach effects were seen at a LOAEL of 66 mg/kg/day which was lower than a 

comparable 90-day oral toxicity study of the parent compound in rats (LOAEL = 156 

mg/kg/day). It should also be noted that when comparing the NOAEL and LOAEL of this study 
Page 27 of 116

to a similar study (90-day oral study in dogs) with parent compound, on a molar basis, the 

NOAELs and LOAELs of DFA and the parent are comparable, however, the effects are 

different. Furthermore, it should be reiterated that in the rat metabolism study with 

flupyradifurone, DFA was formed and detected as approximately 6% of the administered dose.

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

Based on the currently available toxicity and exposure data, the risk assessment team 

recommended the FQPA Safety Factor be reduced to 1X as supported by a complete 

toxicological database. Although there are clinical signs which indicated neurotoxicity in adult 

rats and quantitative increases in susceptibility demonstrated by decreased body weights in F2 rat 

pups and quantitative and qualitative susceptibility demonstrated by increased incidence of dead 

rabbit fetuses, there are clear NOAELs for these effects. The NOAEL for offspring toxicity in 

the 2-generation reproduction study is equivalent to the POD selected for risk assessment while 

the NOAELs for neurotoxicity (clinical signs) and rabbit development toxicity are greater than 

the NOAEL selected as the POD for risk assessment. Therefore, the POD is protective of the 

effects which are indicative of neurotoxicity and susceptibility in rats and rabbits. There is no 

uncertainty in the exposure database. Overall, the data support the determination that an 

additional safety factor is not needed. The details for reducing the FQPA safety factor are 

elaborated below.

4.4.1 Completeness of the Toxicology Database

The flupyradifurone toxicology database is adequate to characterize any potential for prenatal or 

postnatal risk for infants and children, and includes acceptable developmental toxicity studies in 

the rat and rabbit and a rat reproductive toxicity study, as well as acute and subchronic 

neurotoxicity studies. HED waived the required subchronic inhalation toxicity study based on 

flupyradifurone’s physical chemical properties, including low vapor pressure; low acute 

inhalation toxicity (Toxicity Category IV); and the use of a conservative, chronic oral POD that 

results in screening-level MOEs that do not exceed the target MOE for a waiver of 10X the LOC 

(TXR#0056903). 

4.4.2 Evidence of Neurotoxicity

Although there is evidence that flupyradifurone has neurotoxic effects, EPA has a complete set 

of neurotoxicity studies (acute, subchronic, and developmental). The effects of those studies are 

well-characterized and indicate neurotoxic effects that occur at levels above the chronic POD 

that was selected for risk assessment. The NOAEL for the acute neurotoxicity study is being 

used for the acute POD. Therefore, there is no need to retain the 10X FQPA safety factor to 

account for any uncertainty concerning these effects. 

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

There is no evidence that flupyradifurone results in increased susceptibility in in utero rats or 

rabbits in the prenatal developmental studies or in young rats in the 2-generation reproduction 

study. There is quantitative susceptibility in rabbit developmental study and in the pup of the 

reproduction study, but the PoDs are protective of this increased susceptibility.
Page 28 of 116

4.4.4 Residual Uncertainty in the Exposure Database

The exposure databases are complete or are estimated based on data that reasonably account for 

potential exposures. The chronic dietary exposure assessment for flupyradifurone was 

conservatively based on 100% crop treated (CT) assumptions, as well as conservative ground 

and surface drinking water modeling estimates. All of the exposure and risk estimates are based 

on conservative assumptions that do not underestimate risk.

4.5 Toxicity Endpoint and Point of Departure Selections

4.5.1 Dose-Response Assessment

With oral dosing, ADME of flupyradifurone was rapid. The time of peak plasma concentration 

was reached within 1-4 hours, depending on the dosage employed. Elimination was almost 

complete by 24 hours after dosing. The ADME data are consistent with the timing and doses 

causing effects throughout the database as there was little difference in the values of the 

LOAELs between the chronic study and subchronic study in either rats (90-day: 156 mg/kg/day; 

chronic: 120 mg/kg/day) or dogs (90-day: 33 mg/kg/day; chronic: 28 mg/kg/day). The minor 

differences were due to differences in dose selection. However, in the 1-year dog study, the 

effect seen at the LOAEL (28 mg/kg/day) was more extensive than that in the 90-day dog study. 

The 1-year dog study was used to establish the toxicity endpoints and POD for the chronic 

dietary exposure assessment. For short-term incidental oral exposure assessment and short- and 

intermediate-term dermal and inhalation assessment, the selection of the POD (12 mg/kg/day) 

and toxicity endpoint from the 90-day dog study and the 2-generation reproduction study as cocritical is appropriate and is protective of any effects seen in the developmental studies in rats 

and rabbits. In a similar reasoning, the 90-day dog study is also appropriate for toxicity endpoint 

selection for short-term dermal and inhalation exposure assessments. The duration of a 90-day 

dog study also corresponds to the duration of exposure for the intermediate-term dermal and 

inhalation exposure. The reason for employing the 2-generation reproduction study as a cocritical study in selecting the toxicity endpoint for the dermal, and inhalation exposure 

assessment is that the pup body weight loss occurred at similar LOAEL as the skeletal muscle 

atrophy/degeneration in the 90-day dog study. In addition, the pup body weight loss is a clear 

effect of flupyradifurone on the young animal. 

The POD (35 mg/kg) selected from the acute neurotoxicity study is also protective of any effects 

seen in the developmental toxicity studies in rats and rabbits. 

The toxicity endpoints and points of departures are presented in Table 4.5.4.1, and the rationale 

for the selections is presented in Appendix A.

4.5.2 Recommendation for Combining Routes of Exposures for Risk Assessment

HED combines exposure from different routes for each population if the same toxic effects are 

seen for that duration of exposure by each route. Since the same endpoint (skeletal muscle 

atrophy in the dog, co-critical with the pup body weight decrease) was chosen for both dermal 

and inhalation risk assessment, these exposures should be combined.
Page 29 of 116

4.5.3 Cancer Classification and Risk Assessment Recommendation

Flupyradifurone is classified as “Not likely to be Carcinogenic to Humans” based on the absence 

of increased tumor incidence in acceptable/guideline carcinogenicity studies in rats and mice.

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

Assessment

Table 4.5.4.1: Summary of Toxicity Endpoints and Points of Departure for Use in Dietary, Non-Occupational,

and 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)

NOAEL =

35 

mg/kg/day

UFA= 10x

UFH=10x

FQPA SF= 1x

aRfD =0.35 

mg/kg/day

Acute neurotoxicity study –rat

LOAEL = 50 mg/kg/day based on increased 

incidences of piloerection in both sexes and pupil 

dilation in females on Day 1. At the next higher 

dose level (200 mg/kg) or above, lower muscle 

tone, rapid respiration, low arousal, tremors, 

myoclonic jerks, chewing, repetitive licking of 

lips, gait incoordination, flattened or hunched 

posture, dilated pupils, impaired (uncoordinated or 

slow) righting reflex, impaired flexor and tail 

pinch responses and reduced rectal temperature. 

Automated measures of motor activity were also 

reduced in both sexes, compared to controls.

Chronic Dietary (All 

Populations)

NOAEL = 

7.8 

mg/kg/day

UFA= 10x

UFH=10x

FQPA SF= 1x

cRfD = 0.078 

mg/kg/day

cPAD = 0.078 

mg/kg/day

1-year oral toxicity study-dog

LOAEL= 28 mg/kg/day based on minimal to 

slight, focal to multifocal areas of skeletal muscle 

degeneration in gastrocnemius and/or biceps 

femoris muscle. 

Dermal 

Short-(1-30 days) 

and Intermediateterms (1-6 months)

NOAEL = 

12 

mg/kg/day

DAF = 

7.42%a

UFA= 10x

UFH=10x LOC = 100

90-day oral toxicity study-dog

LOAEL= 33 mg/kg/day based skeletal muscle 

atrophy/degeneration. 

2-generation reproduction study- rat as a cocritical study.

NOAEL= 7.7 mg/kg/day

Offspring LOAEL=38.7 mg/kg/day based on pup 

body weight decrease.

Inhalation Short-(1-

30 days) and 

Intermediate-terms 

(1-6 months)

NOAEL = 

12 

mg/kg/day

UFA= 10x

UFH=10x LOC = 100

90-day oral toxicity study-dog

LOAEL= 33 mg/kg/day based on skeletal muscle 

atrophy/degeneration 

2-generation reproduction study- rat as a cocritical study.

NOAEL= 7.7 mg/kg/day

Offspring LOAEL=38.7 mg/kg/day based on pup 

body weight decrease.

Cancer (oral, dermal, 

inhalation)

Classification: “Not likely to be Carcinogenic to Humans” based on data showing no treatment-related 

increase in tumors incidence in rat and mouse carcinogenicity studies. No mutagenic concern was 

reported in the genotoxicity studies. 

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 = 
Page 30 of 116

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 (c = chronic). RfD = reference 

dose. LOC = level of concern. Dermal Absorption Factor = DAF. Toxicity via the inhalation route of exposure is assumed to be 

equivalent to toxicity via the oral route. a: This DAF was calculated based on the dermal absorption values from the 24 hours 

measurements of the most dilute test formulation used in the in vivo rat and in vitro human and rat skin dermal penetration 

studies. To estimate the human dermal absorption factor (DAF), the following equation is used:

 Human DAF = (in vitro human % absorption) x [(in vivo rat % absorption/ (in vitro rat % absorption)]. 

5.0 Dietary Exposure and Risk Assessment 

5.1 Metabolite/Degradate Residue Profile

5.1.1 Summary of Plant and Animal Metabolism Studies

Plants

The metabolic fate of [14C]-flupyradifurone was investigated in potato, apple, rice, cotton, and 

tomato using two radiolabeled forms of flupyradifurone (furoanone-4-

14C and pyridinylmethyl14C) for all crops except tomatoes, where a third radiolabel form was used (ethyl-1-

14C). It is 

noted that no metabolism study was provided for a leafy vegetable. However, the array of 

studies presented with similar results is adequate to translate to the remaining plant types. The 

metabolism of flupyradifurone was qualitatively similar in five different metabolic group types 

(root, fruit, cereal grain, oilseed, and fruiting vegetable) regardless of the application type (foliar, 

soil drench, seed). Moreover, the metabolism was similar for both longer (100 day) and shorter 

(20 day) PHIs. However, the relative amounts of parent and metabolites varied considerably 

with the crop and timing of application. 

Flupyradifurone was generally a major component of the residue in all instances, although its 

contribution was significantly greater at the shorter PHIs typical of most proposed uses. An 

exception was noted in the early season only application to apple trees (PHI 98 days), where 

extensive metabolism/reincorporation of the radiolabel into natural products occurred (with the 

[Furanone-4-

14C]-BYI 02960 label) and parent was subsequently a minor component. 

The soil-treatment type studies showed some total breakdown of flupyradifurone and reincorporation of the radiolabel into carbohydrates, especially for rice and tomato. Cleavage of 

the parent to 6-chloro-3-pyridinemethanol (CHMP) and CHMP reaction products, hydroxylation 

/conjugation of the furanone moiety, cleavage of the pyridinylamine bond with formation of BYI 

02960-difluoroethyl amino furanone and degradation of the furanone moiety with formation of 

BYI 02960 acetic acid and further metabolism products were evident. A radiolabeled study with 

the difluoroacetic acid moiety was conducted only for the drench application to tomato, where 

large amounts of radiolabeled DFA were found. 

Similar paths of metabolism were observed with the foliar treatments (cotton, apple, rice). 

Formation of difluoroacetic acid was likely a significant pathway, as evidenced in the 

determination of non-radiolabeled difluoroacetic acid from the various plant extracts. 

Livestock

Nature of the residue studies with separate radiolabels on the furanone and pyridinyl rings of 

flupyradifurone were conducted with laying hens and a lactating goat. Adequate amounts of the 
Page 31 of 116

administered doses were recovered in all cases. Generally, adequate amounts of the radiolabeled 

residues were released by solvent extraction and subsequently identified or characterized.

Metabolism in poultry was far more extensive than in ruminants. Parent flupyradifurone was 

generally a minor component in hen matrices, with the exception of fat (15% of the TRR) and 

eggs (20% of the TRR) for the pyridinyl label only. Fatty acids were the major metabolic 

product with the furanone label for eggs, fat, and liver, indicating extensive metabolism. With 

the pyridinylmethyl label, acetyl-AMCP, from cleavage of both the furanone and difluroethyl 

groups, was the major residue in eggs, and the major residue in liver was BYI 02960 OH-SA 

from hydroxylation of the furanone. Similar extensive hydroxylation to BYI 02960 OH 

derivatives was seen in ruminant liver.

Metabolism in ruminants was very limited. BYI 02960 was the major portion of the residue in 

fat, muscle, and liver. The parent was also the major component in milk with the pyridinyl label, 

but lactose from total breakdown and reincorporation of the radiolabeled carbon was the major 

component in milk for the furanone label. Significant metabolism was demonstrated only in 

kidney. The major metabolites were BYI 02960 OH (15%-35% of the TRR) and BYI 02960 

OH-glucuonides (26%-31% of the TRR) from hydroxylation followed by conjugation with 

glucuronic acid.

Metabolism in livestock with [Ethyl-1-

14C]-BYI 02960 was not studied. Therefore, nothing can 

be concluded from the metabolism studies about the significance of DFA as a livestock 

metabolite. However, DFA was measured in the livestock feeding studies and was found is 

some matrices to be present in significant quantities. It was the major portion of the residue in 

poultry commodities.

5.1.2 Summary of Environmental Degradation

With respect to environmental fate, flupyradifurone is moderately soluble and is classified as 

mobile to moderately mobile. It is relatively stable to hydrolysis, soil photolysis, anaerobic soil 

metabolism, and anaerobic aquatic metabolism. It does degrade via aqueous photolysis with a 

half-life of approximately three days. Under aerobic aquatic conditions the half live values 

ranged from 237 to 365 days for parent alone and from 676 to 893 days for parent plus 

unextracted residues. The main transformation products observed were DFA and 6-CNA in 

aerobic and anaerobic soil metabolism studies and in field dissipation studies, while BYI 02960-

succinamide and BYI 02960-azabicyclosuccinamide were present in aqueous photolysis studies. 

Preliminary information indicates that DFA is highly mobile and 6-CNA is mobile to moderately 

mobile; therefore, both have the potential to leach to groundwater.

Based on flupyradifurone’s log KOW value of 0.08, and log octanol-air partition coefficient (KOA) 

values of 11, it is not likely to bioconcentrate in terrestrial organisms.1 This is supported by the 

predicted short half-life in the vapor phase. Compounds with a log KOW of three and above are 

 

1 A recent scientific advisory panel (SAP) reported, “Gobas et al. (2003) concluded that chemicals with a log KOA > 

5 can biomagnify in terrestrial food chains if log KOW >2 and the rate of chemical transformation is low. However, 

further proof is needed before accepting these limits without reservations” (USEPA, 2009). This was also supported 

by Armitage and Gobas’s work completed in 2007 (Armitage and Gobas, 2007). 
Page 32 of 116

generally considered to have the potential to bioconcentrate in aquatic organisms. Because 

flupyradifurone’s log KOW is 0.08, it is not expected to significantly bioconcentrate in aquatic 

organisms. 

Study results indicate that flupyradifurone is persistent to very persistent2in soil, sediment and 

water. 

The transformation products that are potentially important for human health drinking water 

exposure include the four major transformation products observed in environmental fate studies 

at greater than 10% applied radioactivity:

 6-chloronicotinic acid (6-CNA),

 difluoroacetic acid (DFA),

 BYI 02960-succinamide (M48), and 

 BYI 02960-azabicyclosuccinamide (M47).

6-CNA is degraded rapidly in three aerobic soil systems (the dissipation half-life, or DT50,

ranged from 3 to 7 days). The degradate DFA was persistent to very persistent in two aerobic 

aquatic systems (DT50 ranged from 121 to 951 days).

Dissipation half-lives for the whole soil profile ranged from 8 to 310 days. Most residues were 

observed in the top 15 cm at all sites; however, flupyradifurone was observed up to a depth of 40 

cm. Field sites varied in percent organic carbon (ranging from 0.8 to 4.4% OM), soil properties, 

and pH (range from 5.5 to 8.2). Carryover of residues at the end of the sampling period ranged 

from 8 to 59%, indicating that flupyradifurone does have the potential to accumulate in soil over 

multiple applications and from year to year. Two of the major degradates observed in laboratory 

studies, 6-CNA and DFA, were also observed in the field studies. M47 and M48 were not 

looked for in the field dissipation studies.

Measured aerobic soil DT50s of 38 to 401 days are uncertain because of high amounts of 

unextracted residues which may or may not constitute residues of concern. Half-lives calculated 

assuming that the unextracted residues do constitute residues of concern range from 79 to 799 

days and are approximately double those for parent alone.

5.1.3 Comparison of Metabolic Pathways

The metabolic pathways in the five crops and application types (soil, foliar, seed) studied are 

qualitatively similar and well understood based on characterization and identification of the 

residues. The metabolism from the confined rotational crop study is similar to the primary crop 

metabolism studies. Parent BYI 02960 is generally the predominant part of the residue; where it 

is not predominant, a natural product (such as glucose) predominates. Difluoroacetic acid is a 

major metabolite, although it has been directly confirmed in only one metabolism study. The 

metabolites are also rat metabolites.

 

2 According to the Toxic Release Inventory Classification System, chemicals with half-lives greater than 60-days are 

classified as persistent and chemicals with half-lives greater than 180 days are classified as very persistent (USEPA, 

2012a).
Page 33 of 116

On basis of the metabolites identified, transformation of flupyradifurone (BYI 02960) proceeds 

by the following pathways:

 oxidative cleavage of the difluoroethylamine bond and formation of difluoroacetic acid

 complete degradation of the furanone moiety and incorporation of carbon atoms into

the natural compound pool, e.g. into glucose/carbohydrates

 cleavage of the pyridinylmethylamine bond and formation of BYI 02960-

difluoroethylamino-furanone and its corresponding counterpart BYI 02960-CHMP, 

which was either conjugated with carbohydrates or oxidised to 6-chloronicotinic acid (6-

CNA)

 hydroxylation of the furanone moiety or the difluoroethyl moiety followed by 

conjugation with carbohydrates, 

 oxidative degradation of the furanone moiety to an acetic acid group followed either by 

conjugation with a carbohydrate or further degradation.

The metabolism in ruminants qualitatively mirrors that of plants. Metabolism is limited, with 

parent BYI 02960 the predominant component of the residue in all commodities. In milk, 

complete degradation of the parent (degradation of the furanone moiety) and reincorporation is 

indicated by the presence of radiolabeled lactose. Other similar metabolic pathways are 

indicated by the presence of 6-CNA from the cleavage of the pyridinylmethylamine bond and the 

presence of BYI 02960-OH-gluA from hydroxylation of the furanone moiety. 

The metabolism in poultry is much more extensive than in plants or ruminants, as evidenced by 

the low or no concentrations of parent BYI 02960 in eggs and tissues. The majority of the 

radiolabeled residue was characterized as fatty acids. The minor metabolites found are 

consistent with metabolites found in the ruminant and in the rat. An exception is BYI 02960 

acetyl-AMCP found only in poultry. 

5.1.4 Residues of Concern Summary and Rationale

Primary Crops: Parent flupyradifurone, glucose, CHMP-di-glyc, 6-CNA, and DFA were 

identified as major residues in the primary crop metabolism studies and/or crop field trials. 

Glucose and CHMP-di-glyc are highly soluble and not of toxicological concern. 6-CNA has 

been characterized as not of toxicological concern as well, and it is expected to be rapidly 

metabolized and conjugated. Parent flupyradifurone and DFA are considered as residues of 

concern (ROC) for risk assessment due to their comparable NOAELs and LOAELs and their 

identification as main residues in the metabolism studies and crop field trials. However, for 

tolerance enforcement, parent flupyradifurone alone is considered an appropriate marker of 

misuse.

Rotational Crops: Parent flupyradifurone and DFA were identified as main components in the 

rotational crops. Other metabolites also observed in the primary crops were identified in the 

rotational crops, but were excluded from the ROC definition based on the absence of a toxicity 

concern. Parent flupyradifurone is recommended as ROC for tolerance enforcement while 

parent flupyradifurone and DFA are recommended as the ROCs for risk assessment.
Page 34 of 116

Processed commodities: Processing studies showed that parent flupyradifurone is stable upon 

processing and therefore an adequate marker of misuse and tolerance enforcement in processed 

commodities. Parent flupyradifurone and DFA are included as the ROCs for risk assessment.

Livestock: Parent flupyradifurone and DFA are the main residues identified in the ruminant

metabolism and feeding studies. Since parent flupyradifurone was observed in the feeding study, 

it is considered an appropriate marker of misuse on ruminant commodities and recommended as 

the ROC for tolerance enforcement.

The poultry feeding study showed DFA as the main residue, and parent flupyradifurone and 

several metabolites at low concentrations relative to DFA. Parent flupyradifurone is predicted to 

be at or below the LOQ of the analytical method in poultry commodities at the calculated poultry 

exposure level. DFA may be slightly above the LOQ in some poultry commodities at the 

exposure level. The ROCKS suggested that the residue definition for enforcement should 

include parent and DFA. However, further consultation with the international partners led to the 

decision to include only parent in the ROC for enforcement. DFA does not have a strong 

advantage as a marker for misuse, and the lack of a DFA feeding study does not allow for 

accurate determination of the DFA residue contribution from DFA itself. Therefore, parent 

flupyradifurone is the ROC for tolerance enforcement and risk assessment in poultry 

commodities. 

Drinking Water: Parent flupyradifurone, DFA, BYI 02960-succinamide and BYI-02960-

azabicyclosuccinamide are included as residues of concern for risk assessment. The aqueous 

photolysis degradates, BYI 02960-succinamide (M48) and BYI 02960-azabicyclosuccinamide

(M47), are recommended for surface water estimates only since these are likely to be formed in 

clear and shallow water bodies. 6-CNA was a major transformation product in the fate studies, 

but is excluded as a ROC, since it is not considered of toxicity concern.

Table 5.1.4: Summary of Metabolites and Degradates to be included in the Risk Assessment and Tolerance 

Expression.

1, 2

Matrix Residues Included in Risk 

Assessment

Residues Included in 

Tolerance Expression

Plants Primary Crop Flupyradifurone

Difluoroacetic acid

Flupyradifurone

Rotational Crop Flupyradifurone

Difluoroacetic acid

Flupyradifurone

Processed Commodities Flupyradifurone

Difluoroacetic acid

Flupyradifurone

Livestock Ruminant Flupyradifurone

Difluoroacetic acid

Flupyradifurone

Poultry Flupyradifurone

Difluoroacetic acid

Flupyradifurone

Drinking Water2 Flupyradifurone, 

Difluoroacetic acid, BYI 

02960-succinamide, and BYI 

02960-azabicyclosuccinamide3

Not Applicable4

1 Difluoroacetic acid and flupyradifurone may need to be considered in separate risk assessments.

2 Refer to Appendix 1 for the names and/or chemical structures of the metabolites/degradates.
Page 35 of 116

3 The aqueous photolysis degradates, BYI 02960-succinamide (M48) and BYI 02960-azabicyclosuccinamide (M47), 

are recommended for surface water estimates only.

4 NA – Not applicable. 

5.2 Food Residue Profile

There are adequate residue data on plant food and feed commodities for the purposes of risk 

assessment and tolerance assessment. Parent flupyradifurone is the major component of the 

residue in food commodities, as evidenced by the plant metabolism studies and the crop field 

trial studies. The parent is quantifiable with the possible exception of tree nuts, where both 

flupyradifurone and DFA are at or below the LOQ (0.01ppm). The crop field trials indicate that 

difluoroacetic acid, DFA, can be a significant portion of the residue for some commodities, most 

notably legume vegetables. Residues of parent generally decline with PHI, but DFA often 

increases with PHI and reaches a plateau around 32 – 35 days after crop treatment. This makes 

DFA a poor marker for tolerance enforcement purposes.

Flupyradifurone shows only a slight tendency to concentrate as a surface residue. It tends to 

distribute throughout the commodity, i.e., is systemic. Flupyradifurone is taken into the plant via 

the roots (soil drench treatment) or translaminarly through the leaf tissue (foliar treatment). The 

residues are qualitatively similar from both paths. Flupyradifurone is stable to the conditions of 

processing. It concentrates in dried (raisins) and concentrated (tomato paste) processed 

commodities, but does not concentrate in juices or oils. It concentrates slightly in outer surface 

commodities such as cereal bran. Storage stability studies on divergent commodity types 

demonstrated that flupyradifurone and DFA are stable in commodities stored frozen for intervals 

that encompass the storage of samples from the crop field trials.

Confined rotational crop studies indicated the potential for flupyradifurone residues present at 

very low levels at PBIs up to one year. However, flupyradifurone is proposed for use on almost 

all food and feed commodities, with the exception of herbs and spices, stone fruit, tropical fruit, 

grass animal feeds, mushrooms, rice, sugar cane, and some oilseeds. Rotational crop studies 

with sugarcane show that a PBI of 14 days is acceptable. Limited field rotational crop studies 

from Europe indicate that flupyradifurone will most likely be <0.01 ppm on rotational crop 

commodities at a one year PBI. For crops without a tolerance and/or a labeled use, except 

sugarcane, a PBI of one year is necessary. 

Livestock feeding studies show that flupyradifurone does transfer to meat, milk, poultry, and 

eggs, but overall transfer to poultry commodities is low at the anticipated exposure levels. 

Adequate feeding concentration levels are available to bracket the exposure anticipated from

residues of flupyradifurone on livestock feed commodities. Parent is the major component of the 

residue in ruminant commodities, but DFA is significant in poultry commodities. No DFA 

feeding studies were available for risk assessment purposes, and DFA levels in livestock 

commodities from the feeding of DFA (in crop matrices) were estimated from a mass balance 

analysis of the flupyradifurone feeding studies.

5.3 Water Residue Profile
Page 36 of 116

Since flupyradifurone is a proposed new chemical, there are no monitoring data currently 

available. The estimated drinking water residues used in the dietary risk assessment were 

provided by EFED (K. White, D415166, 02/28/2014) and incorporated directly into the dietary 

exposure assessment. Estimated water residues were incorporated in the DEEM-FCID into the 

food categories “water, direct, all sources” and “water, indirect, all sources.” Estimated drinking 

water concentrations (EDWCs) were calculated for total toxic residues consisting of parent plus 

M47 plus M48 plus unextracted residues (referred to as “TTR-UN”). The number of growing 

seasons per year was not specified on the label and flupyradifurone could be used for multiple 

seasons per year on one site. Therefore, the estimates incorporated into the dietary assessment 

conservatively assumed three growing seasons per year, and resulted in the highest EDWC.

The EDWC for the acute and chronic assessment was estimated using PRZM-GW (ground

water). The models used to derive the EDWCs are listed in Table 5.3.1. The models and their 

descriptions are available at the EPA internet site: http://www.epa.gov/oppefed1/models/water/. 

Table 5.3.1. Tier I EDWCs for residues of flupyradifurone plus M47 plus M48 plus unextracted 

residues.1

Source of Drinking Water (Model)

TTR-UN concentration in drinking water (μg/L)

Acute Annual Average or Post 

Breakthrough Average

Surface Water (Modified Tier 1 Rice Model) 112 112

Surface Water (PRZM/EXAMS)

46.1 ( 1 season)

47.7 (2 seasons)

52.5 (3 seasons)

13.9 ( 1 season)

20.1 (2 seasons)

22.3 (3 seasons)

Ground Water (PRZM-GW)

117 (1 season)

23.8 (2 seasons)

352 (3 seasons)

102 (1 season)

208 (2 seasons)

307 (3 seasons)

1 For surface water, all values reflect residues of flupyradifurone plus the aqueous photolysis degradates, M47 and M48, plus 

unextracted residues. For groundwater, residue values reflect parent only as recommended by ROCKs because photolysis is less

likely in groundwater, and because PRZM-GW models do not include inputs for photolysis. Residues in groundwater also 

include unextracted residues because it is uncertain whether the unextracted residues are parent or a residue of concern.

Bolded values indicates values used in the acute and chronic assessments. Refinements can be made to get lower EDWCs. 

5.4 Dietary Risk Assessment

5.4.1 Description of Residue Data Used in Dietary Assessment

For both acute and chronic dietary assessments, HED used recommended tolerance-level 

residues for the proposed crops. DEEM default processing factors were used for dried apple, 

dried beef, and dried pear; empirical processing factors were used for processed commodities of 

apple (sauce and juice), coffee, citrus oil, cotton (oil), corn (bran, flour, meal, starch, oil), grape 

(wine, juice), grapefruit (juice), hops (dried cones), limes (juice), lemons (juice), oranges (juice

and peel), peanut (butter, oil), pears (juice), potatoes (chips, flakes, cooked), tomatoes (juice, 

puree, paste), soybeans (oil, milk, flour), and wheat (bran, germ, flour). 

5.4.2 Percent Crop Treated Used in Dietary Assessment

The acute and chronic dietary exposure analysis assumed that 100% of the proposed crops were 

treated with flupyradifurone because there are currently no registered uses. 
Page 37 of 116

5.4.3 Acute Dietary Risk Assessment

The results of the acute analysis indicate that acute dietary (food and drinking water) exposure 

and risk estimates do not exceed HED’s LOC [i.e., <100% acute population adjusted dose 

(aPAD)] for the U.S. population and all population subgroups. At the 95th percentile of 

exposure, the resulting acute dietary risk estimates utilized 24% of the aPAD for the general U.S. 

population and utilized 38% of the aPAD for children 1-2 years old, the most highly exposed 

population subgroup. The results of the acute dietary exposure analysis are included in Table

5.4.6. 

5.4.4 Chronic Dietary Risk Assessment

The chronic dietary (food and drinking water) exposure and risk estimates do not exceed HED’s 

LOC [i.e., <100% chronic population adjusted dose (cPAD)] for the U.S. population or any

population subgroups. The resulting chronic dietary risk estimates utilized 39% of the cPAD for 

the general U.S. population and utilized 84% of the cPAD for children 1-2 years old, the most 

highly exposed population subgroup. Based on the lack of refinement in the assessment, actual 

dietary exposure is expected to be significantly lower.

5.4.5 Cancer Dietary Risk Assessment

Flupyradifurone is classified as “not likely to be carcinogenic to humans”; therefore a cancer 

dietary exposure assessment was not performed. 

5.4.6 Summary Table

Table 5.4.6. Summary of Dietary (Food and Drinking Water) Exposure and Risk for

Flupyradifurone.1

Population Subgroup

Acute Dietary

(95th Percentile) Chronic Dietary

Dietary 

Exposure 

(mg/kg/day)

% aPAD Dietary Exposure

(mg/kg/day) % cPAD

General U.S. Population 0.082755 24 0.030629 39

All Infants (<1 year old) 0.100233 29 0.038123 49

Children 1-2 years old* 0.133852 38 0.065155 84

Children 3-5 years old 0.131183 37 0.055003 71

Children 6-12 years old 0.083856 24 0.035222 45

Youth 13-19 years old 0.063792 18 0.024110 31

Adults 20-49 years old 0.076762 22 0.028118 36

Adults 50-99 years old 0.075170 21 0.027976 36

Females 13-49 years old 0.080078 23 0.028251 36

1The subpopulation with the highest risk estimate is bolded.
Page 38 of 116

5.5 Dietary Exposure Evaluation - DFA

Studies submitted in support of the registration of flupyradifurone indicated that there could be 

exposure to DFA in food (plant and animal based) and drinking water. DFA was also shown to 

be a mammalian metabolite; approximately 6% of flupyradifurone administered to rats was 

converted to DFA, and DFA was a metabolite in the ruminant and poultry metabolism studies. 

The most sensitive toxic effects to be used in the risk assessment for flupyradifurone would not 

be expected from DFA, which has a very different chemical structure. A range-finding and 

subchronic toxicity study with DFA showed different toxic effects (black foci in the glandular 

part of the stomach) than the parent compound (skeletal muscle atrophy and degeneration), 

indicating that risk from DFA should be assessed separately from the parent. DFA is much more 

polar than the parent compound as well; which indicates it may be excreted rapidly. HED 

conducted a screening-level evaluation of DFA to determine if there were any residual concerns 

for exposure to DFA. This evaluation assumed conservative drinking water concentrations, that 

100% of the crops contained DFA at median residue values for all crops except when individual 

median residues were available. For livestock, dietary burdens were calculated based on DFA 

tissue to flupyradifurone feed ratios. Using these conservative inputs, exposure to DFA is 7X 

less than estimated exposure to flupyradifurone for the general US population, and 5X less than 

estimated exposure to flupyradifurone for children 1-2 years old, the highest exposed population 

subgroup. Therefore, since there is similar potency (albeit with different toxic effects) between 

flupyradifurone and DFA, but less exposure expected to DFA than the flupyradifurone, the 

Agency has no additional risk concerns about exposure to DFA.

6.0 Residential (Non-Occupational) Exposure/Risk Characterization

There are no proposed residential uses of flupyradifurone; therefore, a residential exposure 

assessment has not been conducted. A turf transferrable residue (TTR) study is not required for 

flupyradifurone at this time because there are no proposed uses on turf. 

6.1 Residential Bystander Post-application Inhalation Exposure

Based on the Agency's current practices, a quantitative post-application inhalation exposure 

assessment was not performed for flupyradifurone at this time primarily because of the low acute 

inhalation toxicity (Toxicity Category IV), low vapor pressure (7.0 x 10-9 mm Hg at 20oC), and 

the low proposed use rate (0.365 lb ai/A). However, volatilization of pesticides may be a source 

of post-application inhalation exposure to individuals nearby 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, 

and received the SAP’s final report on March 2, 20103. 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 post-application inhalation exposure into 

the Agency's risk assessments. If new policies or procedures are developed, the Agency may 

revisit the need for a quantitative post-application inhalation exposure assessment for 

flupyradifurone.

 

3 Available: http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html
Page 39 of 116

6.2 Spray Drift

Spray drift is a potential source of exposure to those nearby pesticide applications. This is 

particularly the case with aerial application, but, to a lesser extent, spray drift can also be a 

potential source of exposure from the ground application methods (e.g., groundboom and 

airblast) employed for flupyradifurone. The Agency has been working with the Spray Drift Task 

Force (a task force composed of various registrants which was developed as a result of a Data 

Call-In issued by EPA), 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). 4 The Agency is also taking means to qualitatively and 

qualitatively address spray drift as a potential source of exposure in risk assessments for 

pesticides through existing programs such as Ag Drift and chemical specific properties of 

pesticides. The potential for spray drift will be quantitatively evaluated for each pesticide during 

the Registration Review process which ensures that all uses for that pesticide will be considered 

concurrently. 

7.0 Aggregate Exposure/Risk Characterization

In accordance with the FQPA, HED must consider and aggregate (add) pesticide exposures and 

risks from three major sources: food, drinking water, and residential exposures. In an aggregate 

assessment, exposures from relevant sources are added together and compared to quantitative 

estimates of hazard (e.g., a NOAEL or PAD), or the risks themselves can be aggregated. When 

aggregating exposures and risks from various sources, HED considers both the route and 

duration of exposure. There are no residential uses of flupyradifurone; therefore, the aggregate 

risk includes only exposure from food and drinking water. Acute and chronic dietary risks do 

not exceed HED’s LOC for the U.S. population or any population subgroups. Refer to Section 

5.0 for the dietary exposure estimates. 

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 flupyradifurone and any other substances and flupyradifurone 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 flupyradifurone 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/.

 

4 Available: http://www.epa.gov/opp00001/factsheets/spraydrift.htm 
Page 40 of 116

9.0 Occupational Exposure/Risk Characterization

9.1 Short-/Intermediate-Term Occupational Handler Risk

There is potential for short- and intermediate-term occupational exposure to flupyradifurone

during both handler [mixing, loading, and application (via the dermal and inhalation routes)] and 

post-application activities (via the dermal route) based on the proposed uses.

Additionally, for both dermal and inhalation exposures, the PODs selected are considered 

protective of both short- and intermediate-term durations. 

The quantitative exposure/risk assessment developed for occupational handlers is based on the 

following scenarios: 

 Mixing/Loading liquid formulations for aerial, airblast, chemigation, and groundboom 

application; 

 Applying sprays with aerial, airblast, and groundboom equipment; 

 Flagging for aerial applications; 

 Mixing/Loading/Applying using a backpack sprayer and mechanically pressurized 

handgun;

 Primary handling for seed treatment (loading/applying, sewing, bagging treated seed; 

multiple activities); and 

 Secondary handling for seed treatment (planters).

Results are presented for “baseline,” defined as a single layer of clothing consisting of a long 

sleeved shirt, long pants, shoes plus socks, no protective gloves, and no respirator, as well as 

baseline with various levels of PPE as necessary (e.g., gloves, respirator, etc). The proposed 

BYI 02960 480 FS (EPA Reg. No. 264-RRUE) label requires seed treaters and workers cleaning 

the treatment facilities to wear long sleeved shirts, long pants, shoes, socks, and chemical 

resistant gloves. Baggers and others involved in the packaging of treated seed are required to 

wear long sleeved shirts, long pants, shoes, and socks. The proposed SivantoTM (EPA Reg. No. 

264-RRUR) label requires occupational handlers to wear long sleeved shirts, long pants, shoes, 

socks, and chemical resistant gloves. 

There are no risk estimates of concern at baseline (no PPE). For the agricultural uses of 

flupyradifurone, the short- and intermediate-term combined (dermal + inhalation) occupational 

handler MOEs ranged from 260 to 17,000 with baseline PPE. With the addition of chemical 

resistant gloves, as required on the flupyradifurone label, the short- and intermediate-term 

combined (dermal + inhalation) occupational handler MOEs ranged from 800 to 57,000. For the 

proposed seed treatment use of flupyradifurone, the combined (dermal + inhalation) short- and 

intermediate-term MOEs ranged from 2,000 to 14,000. The occupational handler MOE 

estimates are presented in Appendix F.
Page 41 of 116

9.2 Short-/Intermediate-Term Post-Application Risk

9.2.1 Dermal Post-application Risk

HED uses the term post-application to describe exposures that occur when individuals are 

present in an environment that has been previously treated with a pesticide (also referred to as reentry exposure). Such exposures may occur when workers enter previously treated areas to 

perform job functions, including activities related to crop production, such as scouting for pests 

or harvesting. For flupyradifurone, both short- and intermediate-term post-application exposure 

could occur for the proposed agricultural uses. It may be applied throughout the growth season, 

including pre-bloom, during bloom, or following bloom, increasing the likelihood of exposure 

during post-application activities. However, because the POD is the same for dermal short- and 

intermediate-term exposures, one assessment is protective of both durations. 

Chemical-specific dislodgeable foliar residue data have not been submitted for flupyradifurone. 

Therefore, this assessment uses HED’s default assumption that 25% of the application is 

available for transfer on day 0 following the application and the residues dissipate at a rate of 

10% each following day.

The occupational short- and intermediate-term dermal post-application risk estimates ranged 

from 170 to 15,000 on the day of application. A summary of the anticipated worst-case postapplication activities and associated transfer coefficients and MOEs for the proposed crops/use 

sites is provided in Appendix F. 

In accordance with 40CFR158, DFR data are required for all occupational (e.g., crop, nursery, 

greenhouse use sites) or residential (e.g., ornamental and vegetable gardens, pick your own 

farms, retail tree farms) uses that could result in post-application exposure to foliage. In the 

absence of chemical-specific DFR data, EPA uses default values. The 2012 Standard Operating 

Procedures for Residential Pesticide Exposure Assessment includes an analysis of a number of 

DFR studies, which resulted in the selection of a revised default values for the fraction of the 

application rate available for transfer after a foliar application (FAR). These values are based on 

an analysis of 19 DFR studies. Since that time, the Agricultural Re-entry Task Force has 

submitted information (MRID 49299201) that corrects an application rate error made in the 

original submission of “ARF039 – Determination of Dermal and Inhalation Exposure to Reentry 

Workers During Chrysanthemum Pinching in a Greenhouse” (EPA MRID 45344501). As a 

result, the range of FAR values was revised from 2% - 89% to 2% - 47%. In the data, a large 

range of transferability is observed and this variability can potentially be attributable to many 

factors such as active ingredient; formulation; field conditions in the studies; weather conditions 

(e.g., humidity); or many other difficult to quantify factors. Although witnessed across multiple 

chemicals, this range in FAR values is not expected when considering DFR data for a single 

chemical. At this time, the ARTF submission did not alter the selection of 25% as the 

reasonable, high-end default value. Because DFR data are not available for flupyradifurone, 

EPA is using the default value of 25%. Although there may be a small degree of uncertainty in 

the use of the default DFR value for flupyradifurone (i.e., there is a small chance that the FAR

value may exceed the applicable default value), it is likely that the health-protective aspects of 

EPA’s occupational post-application assessment methodology will more than compensate for 
Page 42 of 116

this potential uncertainty. For example, when assessing residential and occupational postapplication exposure to gardens and ornamentals, EPA assumes the following: exposures occur 

to zero-day (i.e., day of application) residues every day of the assessed exposure duration (i.e., 

EPA assumes that no dissipation or degradation occurs, it doesn’t rain, etc); individuals perform 

the same post-application activities performed in the transfer coefficient study day after day (e.g., 

weeding, harvesting, pruning, etc.); and individuals engage in these post-application activities for 

a high-end amount of time every day (represented by data reflecting time spent gardening based 

on survey data).

Given the conservatisms discussed above and the potential compounding nature of these 

conservatisms, EPA is able to rely upon the calculated exposure estimates with confidence that 

exposure is not being underestimated. 

However, since the highest estimated occupational post-application exposure using default DFR 

values for flupyradifurone is not minimal in comparison to the level of concern (i.e., the 

calculated MOE is not greater than 2 times higher than the level of concern, MOE = 170 

compared to the LOC of 100); EPA is requiring the 40CFR DFR data. Therefore, EPA is 

requiring the 40CFR DFR data requirement to facilitate any necessary exposure 

assessments refinements and to further EPA’s general understanding of the availability of 

dislodgeable foliar pesticide residues. The studies should be conducted on three dissimilar 

crops; however, HED specifically recommends including grapes in the studies.

9.2.2 Inhalation Post-application Risk

Based on the Agency's current practices, a quantitative post-application inhalation exposure 

assessment was not performed for flupyradifurone at this time primarily because of the low acute 

inhalation toxicity (Toxicity Category IV), low vapor pressure (7.0 x 10-9 mm Hg at 20oC), and 

the low proposed use rate (0.365 lb ai/A). However, there are multiple potential sources of postapplication inhalation exposure to individuals performing post-application activities in 

previously treated fields. These potential sources include volatilization of pesticides and 

resuspension of dusts and/or particulates that contain pesticides. 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, and 

received the SAP’s final report on March 2, 20105. The Agency is in the process of evaluating 

the SAP report as well as available post-application inhalation exposure data generated by the 

ARTF and may, as appropriate, develop policies and procedures, to identify the need for and, 

subsequently, the way to incorporate occupational post-application 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 occupational post-application inhalation exposure assessment 

for flupyradifurone.

Although a quantitative occupational post-application inhalation exposure assessment was not 

performed, an inhalation exposure assessment was performed for occupational/commercial 

handlers. Handler exposure resulting from application of pesticides outdoors is likely to result in 

higher exposure than post-application exposure. Therefore, it is expected that these handler 

 

5 Available: http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html
Page 43 of 116

inhalation exposure estimates would be protective of most occupational post-application 

inhalation exposure scenarios.

Furthermore, inhalation exposure during dusty mechanical activities such as shaking and 

mechanical harvesting of tree crops is another potential source of post-application inhalation 

exposure. However, the airblast applicator scenario is believed to represent a reasonable worst 

case surrogate estimate of post-application inhalation exposure during these dusty mechanical 

harvesting activities. The non-cancer inhalation risk estimate for commercial airblast application 

does not exceed the Agency’s LOC (i.e., MOE < 100).

A post-application inhalation exposure assessment is not required as exposure is expected to be 

negligible. Seed treatment assessments provide quantitative inhalation exposure assessments for 

seed treaters and secondary handlers (i.e., planters). It is expected that these exposure estimates 

would be protective of most post-application inhalation exposure scenarios.

10.0 References

Ideliz Negrón-Encarnación, D413192, 12/19/2013. Flupyradifurone. Report of the Residues of 

Concern Knowledgebase Subcommittee (ROCKS). 

Jessica Kidwell, 03/18/2014. Flupyradifurone - Summary of Toxicology Science Advisory 

Council (ToxSAC) Meeting of February 6, 2014. 

K. Rury, D413190, 04/08/2014. Flupyradifurone: Acute and Chronic Aggregate Dietary (Food 

and Drinking Water) Exposure and Risk Assessments for Proposed New Uses of the New Active 

Ingredient, Flupyradifurone on Soybean Seeds and the Following Agricultural Crops: Brassica;

Bushberries, except Cranberry; Cereal Grains; Citrus; Cotton; Cucurbits; Fruiting Vegetables; 

Hops; Leafy Vegetables; Legumes; Low Growing Berries; Non-Grass Animal Feeds; Peanuts;

Pome Fruit; Prickly Pears; Root Vegetables; Small Vine Climbing Fruit; Tree Nuts, except 

Almonds; and Tuberous and Corm Vegetables.

K. Rury, D413494, 04/08/2014. Flupyradifurone. Occupational and Residential Exposure 

Assessment for a New Insecticide Active Ingredient Proposed for Use on Soybean Seeds and the 

Following Agricultural Crops: Brassica; Bushberries, except Cranberry; Cereal Grains; Citrus; 

Cotton; Cucurbits; Fruiting Vegetables; Hops; Leafy Vegetables; Legumes; Low Growing 

Berries; Non-Grass Animal Feeds; Peanuts; Pome Fruit; Prickly Pears; Root Vegetables; Small 

Vine Climbing Fruit; Tree Nuts, except Almonds; and Tuberous and Corm Vegetables.

K. White, D415166, 02/18/2014. Drinking Water Exposure Assessment for the Section 3 New 

Chemical Registration for use of Flupyradifurone on a Variety of Agricultural Crops. 

H. Lantum; R. Baggs, D Krenitsky; M Anders, 12/2002. Nephrotoxicity of Chlorofluoroacetic 

Acid in Rats. Toxicological Science 70(2): 261-8.
Page 44 of 116

Monique Perron, TXR#0056903, 03/08/2014. Flypyradifurone: Summary of the Hazard and 

Science Policy Council (HASPOC) Meeting of February 20th: Waiver for a Subchronic 

Inhalation Study.

S. Funk, D415670, D413191, D415685, 02/17/2014. Flupyradifurone. First Food Use. 

Petition for the Establishment of Permanent Tolerances and Registration for Use on Root 

Vegetables Except Sugar Beet (Subgroup 1B), Tuberous and Corm Vegetables (Subgroup 1C), 

Bulb Vegetables (Group 3-07), Leafy Vegetables (Except Brassica) (Group 4), Taro Leaves, 

Turnip Tops; Head and Stem Brassica Vegetables (Subgroup 5A), Leafy Brassica Greens 

Vegetables (Subgroup 5B), Edible-Podded Legume Vegetables (Subgroup 6A), Succulent 

Shelled Pea and Bean (Subgroup 6B), Died Shelled Pea and Bean (except Soybean) (Subgroup 

6C), Foliage of Legume Vegetables (except Soybean) (Subgroup 7A), Soybean (Seed), Fruiting 

Vegetables Except Cucurbits (Group 8-10), Cucurbit Vegetables (Group 9), Citrus Fruits (Group 

10-10), Pome Fruits (Group 11-10), Bushberry (Subgroup 13-07B), Small Fruit Vine Climbing 

(Except Fuzzy Kiwifruit) (Subgroup 13-07F), Low Growing Berry (Subgroup 13-07G), Tree 

Nuts (Group 14-12), Cereal Grains Except Rice (Crop Group 15, Except Rice), Forage, Fodder 

and Straw of Cereal Grains (Crop Group 16), Nongrass Animal Feeds (Forage, Fodder, Straw 

and Hay) (Group 18), Cottonseed (Subgroup 20C), Coffee, Hops, Peanuts, Prickly Pear Cactus, 

and Pitaya. Summary of Analytical Chemistry and Residue Data.
Page 45 of 116

Appendix A. Toxicology Profile and Executive Summaries

A.1 Toxicology Data Requirements

The requirements (40 CFR 158.340) for the proposed food uses of flupyradifurone are in Table A. Use of the new 

guideline numbers does not imply that the new (1998) guideline protocols were used.

Table A.1: Toxicology Data Requirements of Flupyradifurone.

Study

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

no

CR

yes

yes

yes

no

yes*

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 ...................................................

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes 

870.5100 Mutagenicity—Gene Mutation - bacterial.....................

870.5300 Mutagenicity—Gene Mutation - mammalian................

870.5375 Mutagenicity—Structural Chromosomal Aberrations...

870.5550 Mutagenicity—Other Genotoxic Effects.......................

yes

yes

yes

yes

yes

yes

yes

yes

870.6100a Acute Delayed Neurotoxicity (hen)...............................

870.6100b 90-Day Neurotoxicity (hen) ..........................................

870.6200a Acute Neurotoxicity Screening Battery (rat).................

870.6200b 90-Day Neurotoxicity Screening Battery (rat) ..............

870.6300 Develop. Neurotoxicity .................................................

no

no 

yes

yes

CR

-

-

yes

yes

yes

870.7485 General Metabolism ......................................................

870.7600 Dermal Penetration........................................................

870.7800 Immunotoxicity .............................................................

yes

yes

yes

yes

yes

yes

Special Studies for Ocular Effects

Acute Oral (rat)...........................................................

Subchronic Oral (rat)..................................................

Six-month Oral (dog)..................................................

no

no

no

-

-

-

*Study waived by HASPOC (TXR# 0056903).
Page 46 of 116

A.2 Toxicity Profiles

Table A.2.1. Acute Toxicity Profile – Flupyradifurone.

OPPTS 

Guideline No. Study Type MRID Results Toxicity Category

870.1000 Acute Oral - rat 48844101 LD50 cut off ≥ 2000 mg/kg (HDT) 1/3 death

In ACN 2/12 test animals died at 800 mg/kg III

870.1200 Acute Dermal- Rabbit 48844104 LD50 > 2000 mg/kg III

870.1300 Acute Inhalation - Rat 48844105 LC50 > 4671 mg/m3 (4.67 mg/L) IV

870.2400 Primary Eye Irritation -

Rabbit 48844106 Redness of the conjunctivae, reversed within 

48 hours (score 2) IV

870.2500 Primary Dermal 

Irritation - Rabbit 48844107 Non-irritating IV

870.2600 Dermal Sensitization -

mouse

48844108 Non-sensitizing NA

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

Subchronic toxicity studies

870.3100

(28-day)

28-day oral 

toxicity study in 

rats (gavage)

48844149 (2012)

Acceptable /non-guideline

0, 75, 200, 350 mg/kg/day

NOAEL= 75 mg/kg/day

LOAEL = 200 mg/kg/day based on decreased food 

consumption in females; increases in ALT, creatinine, & 

triglycerides in females, enlarged and prominent lobulation 

of the liver in males, diffused follicular cell hypertrophy of 

the thyroid in male. Cytochrome P-450 was induced. 

28-day oral 

toxicity study in 

rats (diet) 

48844150 (2012)

Acceptable/non-guideline

0, 500, 5000 ppm

0, 33.6, 385 mg/kg/day

NOAEL= 33.6 mg/kg/day

LOAEL = 385 mg/kg/day based on decreases in body 

weight, and food consumption; decreases in glucose and 

total bilirubin; and increases in urea nitrogen and total 

cholesterol; prominent lobulation of the liver, and diffused 

follicular cell hypertrophy of the liver.

28-day oral 

toxicity in mice 

(diet0

48844151 (2007)

Acceptable/non-guideline

0, 300, 600, 1200 ppm

M: 0, 40, 78, 166 mg/kg/day

F: 0, 47, 98, 192 mg/kg/day

NOAEL = 166/199 mg/kg/day (M/F) (HDT)

28-day oral 

toxicity in dogs 

(diet) (2 

dogs/sex/dose)

48844152 (2008)

Acceptable/non-guideline

0, 500, 2000, 4000 ppm

M: 16, 62, 118 mg/kg/day

F: 0, 19, 77, 131 mg/kg/day

NOAEL = 62 mg/kg/day

LOAEL = 118 mg/kg/day based on increased thyroid 

weights, enlarged thyroid, diffuse follicular dilatation of the 

thyroid, and decreased food consumption. 

870.3100

(90-day)

90-day oral 

toxicity –rats 

(diet)

48844111 (2012)

Acceptable/Guideline

0, 100, 500, 2500 ppm

M: 0, 6.0, 30.2, 156 mg/kg/day

F:0, 7.6, 38.3, 186 mg/kg/day

NOAEL = 38 mg/kg/day

LOAEL = 156 mg/kg/day based on dark colored thyroid 

associated with follicular cell hypertrophy. Body weight was 

slightly decreased.
Page 47 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

90-day oral 

toxicity –mouse 

(diet)

48844112 (2012)

Acceptable/Guideline

0, 100, 500, 2500 ppm

M:0, 15.6, 80.7 407 mg/kg/day

F: 0, 18.8, 98.2, 473 mg/kg/day

NOAEL = 81 mg/kg/day

LOAEL = 407 mg/kg/day based on consistent decreases in 

body weight (>10%), liver effects (↑ ALP and ALT, ↓ in 

total cholesterol, ↑ in absolute and relative liver weights, ↑ 

in incidence of moderate diffuse hepatocellular hypertrophy 

). Kidney effects (changes in clinical chemistry parameters 

and loss of multifocal/diffuse cortical epithelial cell 

vacuolation & increases in urea).

870.3150 90-oral toxicitydogs (diet)48844114 (2012)

0, 400, 1200, 3600/2400 ppm 

(on week 9 reduced from 3600 

to 2400 ppm due to toxicity of 

the legs)

M: 0, 12, 33, 102/85 

mg/kg/day

F: 0, 12, 41, 107/78 mg/kg/day

NOAEL = 12 mg/kg/day

LOAEL= 33 mg/kg/day based on skeletal muscle myofiber 

atrophy/degeneration decreases in body weight towards the 

end of the study (7-9%). 

870.3200 28-day dermal 

toxicity study in 

rabbits.

48844115 (2012)

Acceptable/guideline

0, 50, 150, 500 mg/kg/day

NOAEL= 500 mg/kg/day (HDT).

No adverse effect was seen at any test groups.

870.3456 Subchronic 

inhalationtoxicity study in 

rats. 

Not available. HASPOC reviewed the data waiver request from the 

Registrant. A subchronic inhalation study is not required for 

flupyradifurone at this time (TXR 0056903).

Chronic toxicity studies

870.4100 Chronic oral 

toxicity study in 

dogs.

(1-year; diet)

48844121 (2012)

Acceptable/Guideline

0, 150, 300, 1000 ppm

M: 0, 4.6, 7.8, 28.1 mg/kg/day

F: 0, 4.1, 7.8, 28.2 mg/kg/day 

N

NOAEL= 7.8 mg/kg/day

LOAEL= 28 mg/kg/day based on minimal to slight, focal to 

multifocal areas of skeletal muscle degeneration in 

gastrocnemius and/or biceps femoris muscle. 

870.4300 Combined 

chronic/ 

carcinogenicity 

study in rats.

48844123 (2012)

Acceptable/guideline

0, 80, 400, 2000 ppm

M: 0, 3.2, 15.8, 80.9 

mg/kg/day

F: 0, 4.5, 22.5, 120 mg/kg/day

Interim sac. at 52 weeks 

(10/sex/dose)

NOAEL = 15.8 / 22.5 mg/kg/day (M/F)

LOAEL = 81/ 120 mg/kg/day (M/F) based on decreases on 

body weight and body weight gains in females, lens opacity 

in females, liver effects (macrovacuolation, increased liver 

weight, eosinophilic/tigroid/mixed foci of hepatocellular 

alterations increased brown pigmentation), thyroid colloidal 

alteration and follicular hypertrophy, and lung effects 

(fomay macrophages and chronic interstitial and 

perivascular inflammation). In addition, iridial Mydriasis 

and retinal fundus were also seen. 

870.4200 Carcinogenicity 

study in mice.

48844122 (2012)

Acceptable/guideline

0, 70, 300, 1500 ppm

M: 0, 10, 43, 224 mg/kg/day

F: 0, 12, 53, 263 mg/kg/day

Interim sac. at 52 weeks 

(10/sec/dose)

NOAEL = 43 mg/kg/day 

LOAEL = 224 mg/kg/day based on a combination decreases 

in terminal body weights (slight) and body weight gains. 

Liver weight increases with associated finding of diffuse 

hepatocellular vacuolation. 

Developmental and reproductive toxicity studies
Page 48 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

870.3700 Developmental 

toxicity - rabbit. 

(gavage)

48844117 (2012) (main study)

Acceptable/non-guideline 

0, 7.5, 15, 40 mg/kg/day 

49113601 (2013)

Range finding study

0, 15, 40, & 80 mg/kg/day

Combined data from both the main and the range finding 

study. 

Maternal NOAEL = 80 mg/kg/day 

Maternal LOAEL could not be established.

Developmental NOAEL = 40 mg/kg/day

Developmental LOAEL = 80 mg/kg/day based increases in 

the number of dead fetuses and dead fetus per litter. 

Reduced fetal body weight (8%).

870.3700 Developmental 

toxicity –rat 

(gavage)

48844116 (2012)

Acceptable/guideline

0, 15, 50, 150 mg/kg/day

Maternal NOAEL = 50 mg/kg/day

Maternal LOAEL = 150 mg/kg/day based increased 

incidence of salivation and decreased food consumption.

Developmental NOAEL = 50 mg/kg/day

Developmental LOAEL =150 mg/kg/day based on increased 

incidence of incomplete parietal and hyoid centrum skull 

bone ossification.

870.3800 2-Generation 

reproduction 

study in rats. 

48844119 (2011)

Acceptable/Guideline

0, 100, 500, 1800 ppm

Premating P1

M: 0, 6.6, 32.5, 117 mg/kg/day

F: 7.7, 38.7, 137 mg/kg/day 

Parental NOAEL = 38.7 mg/kg/day

Parental LOAEL = 137 mg/kg/day based on decreased body 

weights 

Reproductive NOAEL = 38.7 mg/kg/day

Reproductive LOAEL = 137 mg/kg/day based on reduced 

number of estrus cycles

Offspring NOAEL = 7.7 mg/kg/day

Offspring LOAEL = 38.7 mg/kg/day based on decreases in 

pup body weights and pup body weight gains in F2 pups. 

Neurotoxicity studies

870.6200a Acute 

neurotoxicity in 

rats. (gavage)

48844138 (2011)

Acceptable / Guideline

0, 20, 35, 50, 200, 800 mg/kg

NOAEL = 35 mg/kg/day

LOAEL = 50 mg/kg/day based on increased incidences of 

pupil dilation in females on Day 1and piloerection in both 

sexes. At the next higher dose level (200 mg/kg) or above, 

the observed effects included lower muscle tone, rapid 

respiration, low arousal, tremors, myoclonic jerks, chewing, 

repetitive licking of lips, gait incoordination, flattened or 

hunched posture, dilated pupils, impaired (uncoordinated or 

slow) righting reflex, impaired flexor and tail pinch 

responses and reduced rectal temperature. Automated 

measures of motor activity were also reduced in both sexes, 

compared to controls.

870.6200b Subchronic 

neurotoxicity 

study in rats.

48844139 (2011)

Acceptable / Guideline

0, 100, 500, 2500 ppm

M: 0, 5.7, 29.4, 143 mg/kg/day

F: 0, 6.9, 34.8, 173 mg/kg/day

NOAEL = 34.8 mg/kg/day

LOAEL = 143 mg/kg/day based on decreased body weight 

in both sexes

Neurotoxicity was not observed at the doses tested.

870.6300 Developmental 

neurotoxicity 

study in rats.

434203011 (2012)

Acceptable/guideline

0, 120, 500, 1200 ppm

0, 10.3, 42.4, 102 mg/kg/day

Maternal NOAEL = 102 mg/kg/day (HDT)

Offspring NOAEL = 42 mg/kg/day

Offspring LOAEL = 102 mg/kg/day based on statistically 

significant increases in startle response amplitude.
Page 49 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

Metabolism studies: It should be noted that absorption, distribution, metabolism, and elimination (ADME) of flupyradifurone was 

conducted using three different labeling positions: 14C in the pyridinlylmethylene bridge, in the 4-position of furanone ring and in the 

1 position of the ethyl side chain as indicated below:

 Pyridinylmethyl14C Furanone-4-

14C Ethyl-1-14C

870.7485 ADME with 

[pyridinylmethyl14C] BYI 02960- 

male Wistar rats

48844141 (2012)

Acceptable/guideline

Single gavage dose at 2 or 200 

mg/kg

The absorption started immediately after dosing with the 

peak plasma concentration (Cmax) reached approximately 1 

hour after administration in the low dose tests and within 

approximately 2 to 4 hours in the high dose tests.

The distribution of the radioactivity within the body was 

fast. From the maximum plasma level (Cmax), the 

radioactivity level declined slowly down to approximately 

50% of Cmax after 4 – 8 hours in the low dose tests and after 

8 – 24 hours in the high dose tests and down to low values 

around the LOQ in the low dose tests and to approximately 

0.5% of Cmax in the high dose tests by study termination (72 

hours).

Elimination was rapid, mainly by the renal route and 

essentially complete by 72 hours post dosing. Female rats 

exhibited slightly higher renal excretion rates of 

approximately 86% and 90% of the administered dose 

compared to approximately 76% of the dose in males.

Faecal elimination accounted for approximately 23–26% of 

the total administered dose in males, and 7–10% in females.

At the time of sacrifice, 72 hours after administration, the 

radioactive residues in organs and tissues were low, and 

only trace amounts of approx. <0.1 – 0.3% of the total 

administered dose was detected in the body and in the GIT.

The principal metabolic reactions of [pyridinylmethyl14C]BYI 02960 in rats were: (1) hydroxylation followed by 

conjugation with glucuronic acid to or with sulphate; (2) 

cleavage of the difluoroethyl group forming BYI 02960-

des-difluoroethyl; and cleavage of the molecule at the 

pyridinylmethyl bridge forming BYI 02960-6-CNA, which 

was further conjugated with glycine to BYI 02960-hippuric 

acid. Parent compound, three major (BYI 02960-OH, BYI 

02960-6-CNA and BYI 02960-hippuric acid) and five 

minor metabolites were isolated from urine and four of 

them identified by spectroscopic methods. 

[Pyridinylmethyl14C] whole body 

autoradiographyrat

48844142 (2011a)

Acceptable/guideline

A single gavage dose of 5 

mg/kg [pyridinylmethyl14C]BYI02960 in 0.5% aqueous 

Tragacanth®.

The data demonstrate that BYI 02960 was readily absorbed 

from the gastrointestinal tract and distributed throughout the 

body immediately after administration.

In male and female rats, maximum residue levels were 

reached for nearly all organs and tissues at one hour after 

administration. At this time, the levels for liver and kidney 

O

Cl N

N

F

F

O

*

O

Cl N

N

F

F

O

*

O

Cl N

N

F

F

O

*
Page 50 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

were significantly higher than in blood, suggesting a 

preferred clearance from blood and distribution mainly to 

those organs that are responsible for metabolism (liver) and 

excretion (kidney), along with several glands. Very low 

levels were found in the brain, spinal cord and in renal fat. 

From peak levels, a fast decline of radioactivity 

concentrations was observed for all organs and tissues in 

males and females during the whole testing period. 

In both sexes, concentrations fell for most organs and 

tissues below 5% of the maximum after one day and below 

the limit of quantification after seven days post 

administration. No significant retention of 

[pyridinylmethyl14C] BYI 02960 in male and female rats 

was found.

ADME with 

[furanone-4 14C]-

BYI 02960- 

male Wistar rats 

48844143 (2011b)

Acceptable/guideline

Single gavage dose of 2 mg/kg 

bw [furanone-4-

14C]BYI 02960 

in 0.5% aqueous Tragacanth®

[Furanone-4-14C]BYI 02960 was nearly completely 

absorbed since >79% and >91% of the total dose 

administered was detected in the urines and the organs of 

male and female rats, respectively. The absorption started 

immediately after dosing; peak plasma concentration (Cmax) 

was reached approximately 1.5 hours after administration in 

both sexes.

The distribution of the radioactivity within the body was 

fast. From the maximum plasma level (Cmax), the 

radioactivity level declined slowly down to approximately 

50% of Cmax after 8 hours in both sexes and <1% of Cmax 

72h after dosing.

Excretion was rapid and mainly by the renal route. The 

major part of the dose was excreted within 24 hours after 

treatment. At 168 hours after administration, approximately

0.5% of the dose administered for males and approximately 

0.2% for females was still detected in the body.

The parent compound was metabolized to approximately 20 

metabolites in total, consisting of one major (BYI 02960-

OH) and six minor metabolites of an isolated and purified 

compound. Parent compound represented the predominant 

part of the radioactivity in urine but in feces the metabolite,

BYI 02960-OH, was more prominent.

The principal metabolic reactions of [furanone-4-

14C]BYI 

02960 in rats were: (1) hydroxylation followed by 

conjugation with glucuronic acid or with sulphate; (2) 

cleavage of the difluoroethyl group forming BYI 02960-

desdifluoroethyl; (3) cleavage of the molecule at the 

pyridinylmethyl bridge forming BYI 02960-difluoroethylamino-furanone; and (4) cleavage of molecule at the 

nitrogen-carbon bond next to the furanone moiety followed 

by further conversion to C1 and C2 compounds of the 

natural pool including complete degradation to carbon

dioxide.
Page 51 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

[Furanone-4-

14C]

whole body

autoradiographyrat

48844144 (2011b)

Acceptable/Guideline

a single gavage dose of 5 

mg/kg bw [furanone-4-

14C]BYI 

02960 in 0.5% aqueous 

Tragacanth®.

BYI 02960 was readily absorbed from the gastrointestinal 

tract and distributed throughout the body immediately after 

administration. At 2 days after dosing, the excretion of 

radioactivity via urine and feces was almost completed with 

renal excretion as the predominant route. By 168 hours post 

dosing approximately 81% in males and 88% in females of 

the administered dose were recovered in urine and 

approximately 14% in males and 6% in females in the 

feces. Approximately 1 % (females) to 3% (males) of the 

dose was exhaled as 14C-carbon dioxide during a sampling 

period of 48 hours.

In male and female rats, maximum radioactivity levels were 

reached for nearly all organs and tissues at one hour after 

administration. At this time, the values for liver, kidney, 

brown fat, myocardium, nearly all glandular and hormonal 

organs, and the olfactory bulb were higher than that in the 

blood. After seven days, low radioactive residues were 

measured in nearly all organs and tissues. No evidence for 

accumulation or significant retention of [furanone-4-

14C]BYI 02960 in male and female rats

[Furanone-4-

14C]

Metabolism in 

Organs and 

Tissues--rat

48844145 (2012b)

Acceptable/guideline

A single gavage dose of 3 

mg/kg [furanone-4-

14C]BYI02960 in 0.5% aqueous 

Tragacanth® and sacrificed by 

exsanguination under 

anaesthesia at 6 hours post 

dosing.

Highest radioactivity levels were detected in the liver and 

kidney which are the main organs responsible for 

metabolism and urinary excretion. The residue-values for 

plasma and the other tissues were comparable for both 

sexes.

In the 6 h samples of plasma, organs, and tissues, the parent 

compound (BYI 02960) was by far the largest component 

accounting for more than 72% of the total radioactive 

residues (TRR). For all identified metabolites, the values 

were less than 12% of the TRR. In the respective urine 

sample pools, the parent compound was the largest 

radioactive component (≈ 22% of the dose in males and 

38% in females).

The metabolism was qualitatively similar in male and 

female rats. The differences occurred however 

quantitatively. Metabolism of the parent compound to the 

different metabolites was significantly higher in males 

compared to female rats

ADME with 

[Ethyl-1 14C]-

BYI 02960- 

male Wistar rats

48844146 (2011a)

Acceptable/guideline

a single gavage dose of 2 

mg/kg bw [Ethyl-1-

14C]BYI02960 in 0.5% aqueous 

Tragacanth®

[Ethyl-1-

14C]BYI02960 was nearly completely absorbed 

since >85% of the total dose administered was detected in 

the urine and the body without GIT at sacrifice. The 

absorption started immediately after dosing; the peak 

plasma concentration (Cmax) was reached approximately 1 

hour after administration. 

The distribution of the radioactivity within the body was 

fast. From the maximum plasma level (Cmax), the 

radioactivity level declined slowly down to approximately 

50% of Cmax within 8 hours and to approximately 8% of 

Cmax 72h after dosing.

Elimination was rapid and mainly by the renal route. The 

major part of the dose (>87%) was excreted within 24 hours 

after treatment. Approximately 82% of the total 

administered dose was excreted in the urine and 

approximately 14% in the faeces. Only a negligible part of 

0.2% of the total administered dose was detected in expired 

air. At the time of sacrifice, 72 hours after administration, a 
Page 52 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

small proportion of approximately 3% of the total dose 

administered was still detected in the body without GIT. 

Parent compound, one major (BYI 02960-OH) and five 

minor metabolites were identified. The label specific 

metabolite BYI 02960-DFA was additionally identified

(representing ≈5.77% of the administered dose). Parent 

compound represented the predominant part of the 

radioactivity in urine but in faeces samples (≈56% of the 

administered dose) the metabolite BYI 02960-OH was more 

prominent.

The principal metabolic reactions of [ethyl-1-14C]BYI 

02960 in rats were: (1) hydroxylation followed by 

conjugation with glucuronic acid; (2) cleavage of the 

difluoroethyl group leading to BYI 02960-DFA; and (3) 

cleavage of the molecule at the pyridinylmethyl bridge 

leading to BYI 02960-difluoroethyl-amino-furanone.

[Ethyl-1-

14C] -

Metabolism in 

organs and

tissues-rat

48844147 (2012a)

Acceptable/guideline

a single gavage dose of 3 

mg/kg bw [ethyl-1-

14C]BYI02960 in 0.5% aqueous 

Tragacanth®

The distribution of the radioactivity within the central 

compartments of the body (e.g. blood, liver, and kidney) 

was fast for both sexes. Radioactivity residues showed a 

distinctive preference towards the liver and kidney as the 

main organs responsible for metabolism and urinary 

excretion.

Metabolism of BYI02960 was extensive. Metabolic 

reactions took place at least at 3 different structural 

positions of the test compound. The principal metabolic 

reactions of [ethyl-1-14C]BYI 02960 in rats were: (1) 

hydroxylation followed by conjugation with glucuronic 

acid, (2) cleavage of the difluoroethyl group leading to BYI 

02960-DFA and (3) cleavage of the molecule at the 

pyridinylmethyl bridge leading to BYI 02960-difluoroethylamino-furanone.

In the 24 hours samples of plasma, and organs and tissues 

BYI 02960-DFA was the by far largest metabolite 

accounting for more than 50% of the TRR. For all other 

identified metabolites, the values were less than 10% of the 

TRR. The percentage-values of the parent compound in 

these samples ranged from 6 to 38% of the TRR. In the 

respective urine sample pools, the parent compound was the 

largest radioactive component (approximately 48% of the 

dose in males and 77% in females).

The metabolism was qualitatively similar in male and 

female rats. The differences occurred however 

quantitatively. Metabolism of the parent compound to the 

different metabolites was significantly higher in males 

compared to female rats.
Page 53 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

870.7600

(Triple 

pack)

In-vivo Dermal 

absorption study 

in rats.

200 g/L Soluble 

concentrate 

formulation 

(SL200)

48844557 (2010)

Acceptable 

Undiluted 200 g/L SL 

formulation, 0.625 g/L aqueous 

dilution, or 0.1 g/L aqueous 

dilution. Exposure time: 8 

hours.

Using the 24 hour measuring values, 

the potential dermal absorptions were: 

19.6%, 8.3% and 10.3% for undiluted 

200/L SL formulation, 0.625 g/L 

aqueous dilution, and 0.1 g/L aqueous 

dilation, respectively. 

Based on the 24 –

hour measuring 

dermal 

absorption values 

from the in vivo 

and in-vitro 

dermal 

absorption 

studies with 0.1 

g/L aqueous 

dilution , the in 

vivo human 

dermal 

absorption factor 

was estimated to 

be 7.42%

In-vitro dermal 

penetration 

studies with rat 

and human skin.

200 g/L Soluble 

concentrate 

formulation 

(SL200)

48844558 (2010)

Acceptable

Undiluted 200 g/L SL 

formulation, 0.625 g/L aqueous 

dilution , or 0.1 g/L aqueous 

dilution. Exposure time: 8 

hours.

Based on 24-hour measuring interval, 

the dermal penetration were: 

Rat skin: 0.15%, 5.67%, and 6.61% 

for 200 g/L concentrate, 0.625 g/L 

aqueous dilution, and 0.1 g/L aqueous 

dilution, respectively.

Human skin: 0.20% 2.01%, and 

4.75% for 200 g/L concentrate, 0.625 

g/L aqueous dilution, and 0.1 g/L 

aqueous dilution, respectively

The human DAF was derived as 

follows: in vivo human absorption (% 

absorbed) = (in vitro human % 

absorption × in vivo rat % absorbed) ÷

in vitro rat % absorption.

Immunotoxicity study

870.7800 28-Day Dietary 

Immunotoxicity 

Study 

48844148 (2011)

Acceptable / Guideline

0, 125, 600, 3000 ppm

0, 10, 50, 230 mg/kg/day

Systemic Toxicity

NOAEL = 230 mg/kg/day

LOAEL > 230 mg/kg/day

Immunotoxicity

NOAEL = 230 mg/kg/day

LOAEL > 230 mg/kg/day

Immunotoxicity was not observed at the doses tested.

Genotoxicity studies

870.5100 

(84-2 a) 

Mutagenic 

potential of 

Salmonella

typhimurium

48844124 (2009a)

Acceptable/guideline

TA98, TA100, TA102, 

TA1535, TA1537; (-/+ S9) ; 0, 

16, 50, 158, 500, 1581 and 

5000 μg/plate

Negative for mutagenic activity in +/- S9 test systems up to 

the limit dose (5000 μg/plate).

870.5100 

(84-2 a) 

Reverse mutation 

in Salmonella

typimurium.

48844125 (2011)

Acceptable/guideline

TA98, TA100, TA102, 

TA1535, TA1537 (+/-) S9

0, 3, 10, 33, 100, 333, 1000, 

2500 and 5000 μg/plate for 

Experiment1, and 0, 33, 100, 

333, 1000, 2500 and 5000 

μg/plate for Experiment 2. 

(DMSO).

Negative for mutagenic activity in +/- S9 test systems up to 

the limit dose (5000 μg/plate).
Page 54 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

870.5300 In vitro forward 

gene mutation 

assay in 

mammalian cells 

(hamster V79 

Cells) (HPRT 

mutation assay)

48844128 (2009)

Acceptable/guideline

0, 46, 92, 184, 368, 736, 1472 

and 2944 g/mL for 5 hours 

(±S9) at 37C.

Negative in the in the V79/HPRT mutation assay (+/-) S9.

870.5375

(84-2)

In vitro

Chromosome 

Aberration Test 

with Chinese 

Hamster V79 

Cells

48844131 (2009)

Acceptable/guideline

Toxicity assay, 0–3000 g/mL 

(the limit dose) with a 4-hour 

treatment period. Seven 

concentrations from 0–3000 

μg/mL with an 18-hour 

treatment period. 

Negative for the induction of structural and numerical 

chromosome aberrations in cultured Chinese Hamster V79 

cells (+/-) S9.

870. 5395 In vivo mouse 

(Crl:NMRI BR 

mice, males)

micronucleus 

assy (bone 

marrow 

plychromatic 

erythrycytes)

48844134 (2009b)

Acceptable/guidelline

0, 10, 20 and 40 mg/kg by two 

intra-peritoneal injections 24 

hours apart.

Negative for clastogenic and aneugenic activity in the mouse 

bone marrow micronucleus assay.

In vivo 

Micronucleus 

Assay in Bone 

Marrow Cells of 

the Mouse

(females)

48844135 (2011)

Acceptable/guideline

0, 12.5, 25 and 50 mg/kg by 

two intra-peritoneal injections 

24 hours apart.

Negative for clastogenic and aneugenic activity in the mouse 

bone marrow micronucleus assay.

Toxicity Studies on Metabolites 

Difluoroacetic acid—(BCS-AA56716)

14-Day oral 

toxicity study-rat 

(dietary)

48844153 (2011)

0, 500, 2000, & 8000 ppm

M: 0, 48, 187 & 745 mg/kg 

bw/ day 

F:0. 51, 201 & 800 mg/kg bw/ 

day

NOAEL = 51 mg/kg/day

LOAEL = 187 mg/kg/day based on mean glucose 

concentration reduced by 41% in males and 48% in females 

(p <0.01), mean urea concentration was 25% higher in 

females (not statistically significant) in comparison to the 

controls.

90-day oral 

toxicity study-rat

(dietary)

48844113 (2012)

Acceptable/guideline

0, 200, 1000, 6000 ppm

M: 0, 12.7, 66.2, 380 

mg/kg/day 

F:0, 15.6, 78.7, 472 mg/kg/day

NOAEL = 12.7/15.6 mg/kg/day (M/F)

LOAEL = 66.2/78.8 mg/kg/day (M/F) based on a number of 

findings including reduced body weight approaching 10% 

on week 13, decreased food consumption, black foci in the 

glandular part of the stomach with correlated histopathology 

finding of focal glandular erosion/necrosis. In addition, 

slight decreases in hemoglobin, mean corpuscular volume, 

mean corpuscular hemoglobin, and hematocrit.

Bacterial reverse 

mutation

(Salmonella 

typhimurium strains 

TA98, TA100, 

TA102, TA1535, 

TA1537)

48844126 (2010a)

Acceptable/guideline

0, 3, 10, 33, 100, 333, 1000, 

2500 and 5000 μg/plate

(+/-) S9

Negative for mutagenic activity Salmonella Typhimurium.

(+/-) S9
Page 55 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

Mammalian cell 

gene mutation 

(Chinese 

Hamster V79 

cell/HPRT)

48844129 (2010a)

Acceptable/guideline

0, 30, 60, 120, 240, 480 and 

960 g/mL (+/-) S9

Negative in (+/-) S9 V79/HPRT mutation assay.

In vitro 

cytogenetics

(chromosome 

aberration assay 

in Chinese 

hamster V79 

cells)

48844133 (2010b)

Acceptable/guideline

0, 240, 480 and 960 μg/mL

(+/-) S9

Negative for the induction of structural and numerical 

chromosome aberrations in cultured Chinese Hamster V79 

cells (+/-) S9.

BCS-CC98193 (BYI 02960-difluoroethyl-amino-furanone)

28-Day oral 

toxicity study –

rat

(dietary)

48844109 (2012)

Acceptable/Guideline

0, 200, 800, 3000 ppm

M:0, 17, 67, 244 mg/kg/day

F:0,19, 76, 256 mg/kg/day

NOAEL = 244/273 mg/kg/day (M/F) (HDT)

No adverse effect was found at all tested dose levels.

Bacterial reverse 

mutation

Salmonella 

typhimurium

strains TA98, 

TA100, TA102, 

TA1535, TA1537

48844127 (2010b)

Acceptable/guideline

0, 3, 10, 33, 100, 333, 1000, 

2500 and 5000 μg/plate for 

Experiment1, and 0, 33, 100, 

333, 1000, 2500 and 5000 

μg/plate for Experiment 2.In 

DMSO.

Negative tested up to the limit dose 5000 μg/plate (+/-) S9.

Mammalian gene 

mutation 

(Chinese 

Hamster V79 

Cells/HPRT) 

48844130 (2011)

Acceptable/guideline

0, 51.3, 102.5, 205, 410, 820 

and 1640 g/mL (+/-) S9.

Negative in the V79/HPRT mutation assay (+/-) S9

In vitro 

cytogenetics

(chromosome 

aberration assay 

in Chinese 

hamster V79 

cells)

48844133 (2011a)

Acceptable/guideline

0–1636 g/mL (the limit dose)

Positive (-S9)

Negative (+S9)

In vivo mouse 

bone marrow 

micronucleus 

assay

48844136 (2011b)

Acceptable/guideline

0, 125, 250 and 500 mg/kg by 

two intra-peritoneal injections 

24 hours apart

Negative for clastogenic or aneugenic activity in the mouse 

bone marrow micronucleus assay.

In vivo UDS with 

rat hepatocytes

48844137 (2011c)

Acceptable/guideline

0, 1000 and 2000 mg/kg by a 

single oral gavage dose.

Negative in unscheduled DNA synthesis at up to the limit 

dose of 2000 mg/kg bw.

(6-chloro-3-pyridyl)methanol (IM-0)
Page 56 of 116

Table A.2.2. Repeated dosing, neurotoxicity, mutagenicity, and metabolism studies on Flupyradifurone.

Guideline 

No. Study Type MRID No. (Date)/Classification/ Doses Results

Bacterial reverse 

gene mutation 

assay

Salmonella 

typhimurium

strains TA98, 

TA100, TA1535 

and TA1537, and 

Escherichia coli

strain WP2uvrA

44988432 (1997)

Acceptable/guideline

0, 313, 625, 1250, 2500 and 

5000 μg/plate. (in DMSO)

Negative up to the limit dose (5000 μg/plate) with (+/-) S9.

6-chloronicotinic acid (IC-0)

Bacterial reverse 

gene mutation 

assay

Salmonella 

typhimurium

strains TA98, 

TA100, TA1535 

and TA1537, and 

Escherichia coli

strain WP2uvrA

44988502 (1997b)

Acceptable/guideline

0, 313, 625, 1250, 2500 and 

5000 μg/plate. (in DMSO).

(+/-) S9

Negative up to the limit dose (5000 μg/plate) with (+/-) S9.

A.3 Hazard Identification and Endpoint Selection

A. 3.1 Acute Reference Dose (aRfD) – General population including female 13+

Study Selected: Acute neurotoxicity study in rats

MRID No.: 48844138

Dose and Endpoint for Establishing aRfD: NOAEL = 35 mg/kg/day. LOAEL = 50 mg/kg/day

based on increased incidences of piloerection in both sexes and pupil dilation in females on Day 

1. At the next higher dose level (200 mg/kg) or above, the observed effects included lower 

muscle tone, rapid respiration, low arousal, tremors, myoclonic jerks, chewing, repetitive licking 

of lips, gait incoordination, flattened or hunched posture, dilated pupils, impaired (uncoordinated 

or slow) righting reflex, impaired flexor and tail pinch responses and reduced rectal temperature. 

Automated measures of motor activity were also reduced in both sexes, compared to controls.

Uncertainty Factor (UF): 100 (10x intraspecies, 10x interspecies); FQPA SF = 1x

Comments about Study/Endpoint/Uncertainty Factor: The acute neurotoxicity study is 

appropriate; the clinical sign, pupil dilatation, is one of the classical signs produced by activation 

of nicotinic acetylcholine receptor (nAchR) and is a single dose effect. The selected NOAEL is 

also protective of the effects seen in the rabbit developmental toxicity study, where increased 

number of dead fetuses and dead fetuses per litter were seen at 80 mg/kg/day.

aRfD = 35 mg/kg/day = 0.35 mg/kg/day

 100

aPAD = 0.35 mg/kg/day = 0.35 mg/kg/day

1
Page 57 of 116

A.3.2 Chronic Reference Dose (cRfD)

Study Selected: One year Oral Toxicity Study in Dogs

MRID No.: 48844121

Dose and Endpoint for Establishing cRfD: NOAEL = 7.8 mg/kg/day. LOAEL = 28 mg/kg/day 

based on skeletal muscle degeneration.

Uncertainty Factor (UF): 100 (10x intraspecies, 10x interspecies); FQPA SF = 1x

Comments about Study/Endpoint/Uncertainty Factor: The one year dog study is appropriate for 

both the duration and population of concern. The effect (skeletal muscle degeneration) found at 

the LOAEL or above is rather serious and may relate to mode of the pesticidal action (activation 

of nicotinic acetylcholine receptions at the neuromuscular junction) of the chemical. In addition 

the NOAEL (7.8 mg//kg/day) is protective of the offspring effect (decrease in F2 pup body 

weight) observed in the 2-generation reproduction study. 

cRfD = 7.8 mg/kg/day = 0.078 mg/kg/day

 100

cPAD = 0.078 mg/kg/day = 0.078 mg/kg/day

A.3.3 Incidental Oral Exposure (Short-Term)

Selected Study: 90-Day Oral Toxicity Study in Dogs

Co-critical study: 2-Generation reproduction study in rats

MRID No.: 48844114

Dose and Endpoint for Risk Assessment: NOAEL = 12 mg/kg/day. LOAEL = 33 mg/kg/day 

based on skeletal muscle atrophy/degeneration 

Uncertainty Factor (UF): Residential Level of Concern for MOE = 100

Comments about Study/Endpoint/Margins of Exposure: This study is appropriate for the 

duration of exposure. In addition, the toxicity endpoint (skeletal muscle degeneration) is rather 

serious and may relate to mode of the pesticidal action (activation of nicotinic acetylcholine 

receptions at the neuromuscular junction) of the chemical and the dog is the most sensitive 

species. In addition the NOAEL (12 mg//kg/day) is protective of the offspring effect (decrease in 

F2 pup body weight) observed in the 2-generation at 38.7 mg/kg/day in the 2-generation 

reproduction study. The 2-generation reproduction study is selected as a co-critical study in 

selection. 

A.3.4 Dermal Exposure (Short-term; 1-30 Days)

Selected Study: 90-day oral toxicity study in dogs

Co-critical study: 2-Generation reproduction study in rats

MRID No.: 48844114

Dose and Endpoint for Risk Assessment: NOAEL = 12 mg/kg/day. LOAEL = 33 mg/kg/day 

based on skeletal muscle atrophy/degeneration decreases in body weight towards the end of the 

study (7-9%).

Uncertainty Factor (UF): MOE = 100
Page 58 of 116

Comments about Study/Endpoint/Margins of Exposure: This study is appropriate for the duration 

of exposure. In addition, the toxicity endpoint (skeletal muscle degeneration) is rather serious 

and may relate to mode of the pesticidal action (activation of nicotinic acetylcholine receptions at 

the neuromuscular junction) of the chemical and the dog is the most sensitive species. In addition 

the NOAEL (12 mg//kg/day) is protective of the offspring effect (decrease in F2 pup body 

weight) observed in the 2-generation at 38.7 mg/kg/day in the 2-generation reproduction study.

Inhalation Exposure (Short- and Intermediate-Term) 

Selected Study: 90-day oral toxicity study in dogs

Co-critical study: 2-generation reproduction study in rats.

MRID No.: 48844114

Dose and Endpoint for Risk Assessment: NOAEL = 12 mg/kg/day. LOAEL = 33 mg/kg/day 

based on skeletal muscle atrophy/degeneration. 

Uncertainty Factor (UF): MOE =100

Comments about Study/Endpoint/Margins of Exposure: No route specific (inhalation) study is 

available. This dog oral toxicity study is appropriate for the duration of exposure. In addition, 

the toxicity endpoint (skeletal muscle degeneration) is rather serious and may relate to mode of 

the pesticidal action (activation of nicotinic acetylcholine receptions at the neuromuscular 

junction) of the chemical and the dog is the most sensitive species. In addition the NOAEL (12 

mg//kg/day) is protective of the offspring effect (decrease in F2 pup body weight) observed in 

the 2-generation at 38.7 mg/kg/day in the 2-generation reproduction study.

A.4 Executive Summaries

A.4.1 Subchronic Toxicity

870.3100 90-Day Oral Toxicity - Rat

In a subchronic dietary study (MRID 48844111), BYI 02960 (99.5%; NLL 7780-44-6) was 

administered to six to seven week-old Wistar Rj:WI (IOPS HAN) rats in groups of 

10 rats/sex/dose at 0, 100, 500, or 2500 ppm daily for 95 to 97 days (0/0, 6.0/7.6, 30.2/38.3, and 

156/186 mg/kg bw/d for M/F, respectively). Two additional groups (10 rats/sex/dose) received 0 

or 2500 ppm for the same treatment period, then received diet free of the test substance for an 

additional 30 or 31 day recovery period.

There were no test substance related effects on clinical signs or FOB parameters, unscheduled 

mortality, ophthalmology, or urinalysis parameters. The study also examined test substance 

concentrations in plasma during the last week of the study; the results indicated a linear 

increasing trend between plasma concentration vs. dose level administered between 100 and 500 

ppm, but a sub-linear increasing trend between 100 and 2500 ppm plasma concentrations of test 

substance. A slight sex-specific difference in test substance plasma concentrations was noted, 

with higher levels observed in females (1.3–1.7× higher than males).

At 2500 ppm, decreases in mean absolute body weight and body weight gains were observed in 

both sexes during the treatment period. During day 8 measuring interval, the absolute body 

weight decrement in females reached 10%, and at day 14 the decrease was 8%. Thereafter, the 
Page 59 of 116

decrease in body weight was below 8% and persisted until the end of the study. The slight body 

changes were not considered adverse in males; for females, the decrease (↓10%) reached the 

magnitude of being adverse at the beginning of the study. The adverse body weight effect in 

females might reflect higher concentrations of the test compound in females relative to males.

The food consumption was consistently decreased in both males and females (↓9% to ↓29%). 

The increased incidence of gross and histopathological changes in the thyroid (dark color thyroid 

and thyroid follicular cell hypertrophy) combined with increased absolute and relative thyroid 

weights are considered to be adverse.

No adverse effects were found at 100 and 500 ppm.

Therefore, the NOAEL in both sexes was 500 ppm (38 mg/kg bw/day); LOAEL was 2500 

ppm (156 mg/kg bw/day) based on increased incidence of thyroid follicular cell 

hypertrophy with associated increases of absolute and relative thyroid weights, decreased 

body weights in females, and decreased food consumption in both sexes.

This study is classified as fully reliable (acceptable/guideline) and satisfies guideline 

requirements for a subchronic oral toxicity in rats [OPPTS 870.3100; OECD 408 (1998)].

870.3100 90-Day Oral Toxicity - Mouse

In a 90-day dietary study (MRID 48844112), BYI 02960 (99.5%; NLL 7780-44-6) was 

administered to six week old C57BL/6J mice in groups of 10/sex/dose at 0, 100, 500, or 2500 

ppm (equivalent to 0/0, 15.6/18.8, 80.7/98.2, or 407/473 mg/kg bw/d). Analysis of the plasma 

concentration of the test substance was conducted on blood samples of 5/sex/dose group.

Under the conditions of this study BYI 02960 did not affect mortality or produce clinical signs of 

toxicity. In addition, the test chemical did not produce adverse effects at 100 and 500 ppm. 

In males at 2500 ppm, lower body weight gain led to terminal body weights being 10% lower 

than controls. While decreases in body weight gain in males may be associated with decreased 

absolute food consumption, particularly in study weeks 1 to 2, where up to 11% lower 

consumption was observed Terminal body weights were unaffected in 2500 ppm females when 

accounting for differences in starting body weights.

At 2500 ppm, clinical chemistry examinations showed a 30/24% (M/F, p<0.01) decrease in 

serum cholesterol, 38% (p<0.01) increase in alkaline phosphatase (ALP) activity in male serum, 

and 106% increase in alanine aminotransferase (ALT) activity in female serum. Absolute and 

relative liver weights were increased in females at 2500 ppm. When the clinical chemistry 

parameter changes were considered in the context of an increased severity of diffuse 

centrilobular hepatocellular hypertrophy in both sexes, these findings were consistent with 

toxicologically adverse hepatocellular toxicity in both sexes.

Additionally at 2500 ppm, in clinical chemistry examinations there were increases of 51% in 

serum urea (p<0.05) in males and a 5% decrease (p<0.05) in serum protein in both sexes. When 

considered in the context of an 11% (p<0.01) decrease in absolute and relative (to brain weight) 

kidney weight, along with the absence of multifocal/diffuse cortical epithelial cell vacuolation, 
Page 60 of 116

collectively, these changes suggest test substance related, toxicologically adverse renal toxicity 

in males at 2500 ppm. 

The NOAEL was 500 ppm (81 mg/kg/day) for both sexes. The LOAEL was 2500 ppm (407 

mg/kg/day) based on based on consistent decreases in body weight (>10%) with associated 

reduction in body weight gains in male, liver effects (↑ ALP and ALT, ↓ in total cholesterol, 

↑ in absolute and relative liver weights, increased incidence of moderate diffuse 

hepatocellular hypertrophy ). Kidney effects (changes in clinical chemistry parameters and 

loss of multifocal/diffuse cortical epithelial cell vacuolation & increases in urea). 

The results of the plasma analysis showed that test substance concentrations in plasma at 90-days 

were higher in males than in females at all dose levels. In both sexes, a generally linear 

correlation between administered concentrations of test substance and plasma concentrations was 

observed. 

This study is classified as fully reliable (acceptable/guideline) and satisfies guideline 

requirements for a subchronic oral toxicity in mice [OPPTS 870.3100; OECD 408].

870.3150 90-Day Oral Toxicity - Dog

In a 90-day dietary study (MRID 48844114), BYI 02960 was administered to seven to eight 

month old beagle dogs in groups of 4/sex/dose at dietary concentrations of 0, 400, 1200, or 

3600/2400ppm (high dose reduced from 3600 ppm starting on study week 9). Dose levels were 

equivalent to 0/0, 12/12, 33/41, and 102[85]/107[78] mg/kg bw/d respectively. 

BYI 02960 did not affect mortality, ophthalmology, or urinalysis parameters in this study.

Clinical signs were confined to the 3600 ppm dose groups, where one male and one female 

experienced unsteady/stiff back legs and lower back on study days 44 (both sexes) and 53 and 54 

(for the male only). These findings led to reduction of the dose to 2400 ppm from study week 9 

(day 56) onwards.

Over study days 0 to 14, both sexes at 3600 ppm experienced group mean body weight loss of 

4/6% (M/F), respectively. Mean body weights at 3600/2400 ppm were over 10% lower than 

controls by study week 7 (11/14% decrease in M/F, statistically insignificant), reached a 

maximum difference of 14/16% (p<0.05 in M only) lower than controls at study week 8, and 

partially recovered thereafter, resulting in terminal body weights 11/13% lower than controls at 

study week 13. Group mean body weight gains in both sexes at 1200 ppm gradually decreased 

from controls from study week 3 onwards, resulting in 9/7% lower body weights compared with 

controls at study week 13. The decreases in body weight gain as well as instances of body weight

loss were at least partially accounted for decreased food consumption. 

In haematology, dose- and time point-related trends were observed for decreases in RBC count, 

plasma haemoglobin and haematocrit compared with controls, and the findings are consistent 

with a treatment-related effect at 3600/2400 ppm. 

In clinical chemistry, both sexes at ≥ 1200 ppm had marked increases in group mean creatine 

kinase (CK), aspartate aminotransferase (AST), and alanine aminotransferase activities (ALT), 
Page 61 of 116

and at 3600/2400 ppm there were decreased serum creatinine levels and increased serum 

cholesterol in both sexes, and increased glucose in females. However, all findings but ALT 

activity in males at ≥1200 ppm had resolved by study day 84. 

In terminal findings, organ weight changes were observed in 3600/2400 ppm males, with relative 

(to body weight) kidney weights increased by 31% (p<0.05), absolute prostate weights increased 

by 67% (p<0.05) and relative prostate weights by 88% (p<0.05).Increased relative kidney 

weights (16%; not statistically significant) were also observed in females at 3600/2400 ppm, and 

increased absolute (14/11% in M/F, p<0.05 in M only) and relative (28/24% in M/F, p<0.05) 

liver weights were also seen at 3600/2400 ppm.

Pathology examinations reported skeletal muscle myofiber atrophy/degeneration in 2/4 males 

(both minimal severity) and all four females (3 minimal, 1 slight severity) at 1200 ppm, with an 

increase in severity at 3600/2400 ppm in males only (1 minimal, 1 slight). All four females at 

3600/2400 ppm reported skeletal muscle myofiber atrophy/degeneration of minimal severity. 

Accumulation of brown pigment to a minimal severity was seen in hepatic Kupffer cells of 2/4 

females at 3600/2400 ppm, but was absent from all other groups.

The no-observed-adverse-effect level (NOAEL) for both sexes was 400 ppm (12 mg/kg/day). 

The LOAEL was 1200 ppm (33 mg/kg/day), based on increased incidence of skeletal muscle 

myofiber atrophy/degeneration with associated increases in CK. AST, and ALT levels.

This study is classified as fully reliable (acceptable/guideline) and satisfies guideline 

requirements for a subchronic oral toxicity in dogs [OPPTS 870.3150; OECD 409].

870.3200 21/28-Day Dermal Toxicity – Rat

In a 28-day dermal toxicity study (MRID 48844115), BYI 02960 (96.2%) was applied to the 

shaved, intact dorsal skin of male and female Wistar: Crl:WI(Han) rats (10/sex/dose). The test 

material was moistened with deionized water and applied onto approximately 58 cm2shave skin

for 28 daily (consecutive) applications. The rats were exposed to the test material for a 

minimum of 6 hours per day at 0, 50, 150 and 500 mg/kg bw/day. Parameters evaluated 

included body weight, body weight gain, food consumption, clinical signs, clinical pathology, 

ophthalmology, organ weights, and gross and microscopic pathology. 

Under the conditions of this study, no effects attributable to exposure to BYI02960 were 

observed in body weight, body weight gain, food consumption, clinical signs, clinical pathology, 

ophthalmology, or gross and microscopic pathology data.

The absolute and relative liver weights at 500 mg/kg/day males were decreased by 6% and 9%, 

respectively, compared to control rats, with only the relative decrease obtaining statistical 

significance. There were no test material related clinical or gross or microscopic pathology 

changes to correlate this finding. Consequently, based on the results of this study, the noobserved-adverse-effect-level (NOAEL) was 500 mg/kg bw/day (HDT) for both male and 

female rats. The study report stated that the highest dose, 500 mg/kg bw, was selected after 

consideration of the amount of test material that could be reliably applied to the skin.
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This study is considered to be fully reliable (acceptable/guideline) and to meet the data 

requirements for a 28-day dermal toxicity study (OPPTS 870.3200; OECD 410).

870.3465 90-Day Inhalation – Rat

The inhalation study was waived (HASPOC, 2/20/2014, TXR# 0056903) 

A.4.2 Prenatal Developmental Toxicity

870.3700a Prenatal Developmental Toxicity Study - Rat

In a developmental toxicity study (MRID 48844116), groups of mated Crl:CD(SD) female rats 

(23/dose group) received BYI 02960 (96.2% purity) in 0.5% aqueous methylcellulose 400 

vehicle at doses of 0, 15, 50, or 150 mg/kg bw/day (10 mL/kg bw dosing volume) on gestation 

days (GD) 6 to 20. For dams, parameters evaluated were: body weight, body weight gain, food 

consumption, survival, clinical signs, reproductive outcomes, and gross pathology. Fetal

parameters evaluated were: fetal body weight, incidences of dead fetuses and/or fetal resorptions, 

and incidences of external, visceral, head, and skeletal malformations and variations.

For dams, there were no test substance-related effects on survival, reproductive outcomes, or 

gross necropsy findings. The mean number of corpora lutea, implantation sites, resorptions, live 

fetuses, fetal weight and sex ratio were comparable across all groups and controls. An increased 

incidence of salivation (20/23) in 150 mg/kg bw/day animals was noted and considered a 

treatment-related effect. Additionally, a lower gestational body weight gain in females was noted 

as a treatment-related effect, with a 16% lower corrected body weight gain at 150 mg/kg bw/day

compared with controls, and statistically significant decreased food consumption in the same 

dose group over GD 6 to 12 compared with controls. No adverse maternal effects were observed 

in the 50 and 15 mg/kg bw/day groups.

In fetuses, there were no test substance-related effects on the incidence of malformations or 

external variations. However, at 150 mg/kg bw/day, the incidence of the variations “parietal 

(unilateral/bilateral): incomplete ossification” and “hyoid centrum: incomplete ossification” were 

higher than in the control group and were outside the in-house historical control at both litter and 

fetal levels. These findings were indicative of a slightly delayed fetal development and 

considered to be test substance related. No adverse developmental effects were found in 50 and 

15 mg/kg bw/day fetuses. 

The maternal NOAEL was 50 mg/kg bw/day, and maternal LOAEL was 150 mg/kg 

bw/day, based on salivation, lower gestational body weight gain and decreased food 

consumption during the treatment period.

The developmental NOAEL was 50 mg/kg bw/day; developmental LOAEL was 150 mg/kg 

bw/day, based on increased incidences of incomplete parietal and hyoid centrum skull bone 

ossification indicative of delayed fetal development. 

This study is fully reliable (acceptable/guideline) and satisfies the requirements for a 

developmental toxicity study in rats (OPPTS 870.3700; OECD 414; Directive 87/302/EEC Part 

B; MAFF 12 Nousan 8147). 
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870.3700b Prenatal Developmental Toxicity Study - Rabbit

In a developmental toxicity study (MRID 48844117) by oral gavage dosing, time-mated female 

NZW (Crl: KBL) rabbits in groups of 23/dose received BYI02960 (96.2% purity) in 0.5% 

aqueous methylcellulose 400 vehicle at doses of 0, 7.5, 15, or 40 mg/kg bw/d in dosing volumes 

of 4 mL/kg bw/d between gestation days (GD) 6–28. For the dams, the following parameters 

were evaluated: body weight, body weight gain, food consumption, survival, clinical signs, 

reproductive outcomes, liver weight and gross pathology. Foetal parameters evaluated were the 

following: foetal body weight, incidences of dead fetuses, and external, visceral, head, and 

skeletal malformations and variations.

There were no test substance-related effects on maternal clinical signs, reproductive parameters 

litter data endpoints, or gross necropsy findings. However, during GD 6–8, decreased corrected 

body weight gain and decreased food consumption were observed in 40 mg/kg bw/d maternal 

animals. However, the absolute body weights of the treated and the controls groups were 

comparable. The decreases in body weight gain and in the food consumption were marginal; 

these observations were considered not to be toxicologically adverse in this case. Therefore, the 

maternal NOAEL was established at 40 mg/kg bw/d, based on no adverse effects were seen 

at the highest dose tested. When the data of this main study were considered in 

combination with those of the range finding study (MRID 49113601) (Attachment: 

Abbreviated Review of the Range Finding study), a maternal LOAEL was established at 80 

mg/kg bw/d based on the markedly decrease in food consumption starting GD 6-10 and 

persisted at lower magnitude to the end of the study and clinical signs (no feces or few feces 

over several days).

As no evidence of developmental toxicity was observed, and no evidence of an increased 

frequency of treatment-related, toxicologically adverse external, visceral or skeletal 

malformations and variations were found; the developmental toxicity, NOAEL is 40 mg/kg 

bw/d, the highest dose tested in this study. However, at 80 mg/kg bw/d in the range finding 

study, there was an increase in the number of dead fetuses (7 fetuses in 4 litters) relative to the 

controls (2 fetuses in 1 litter). This finding demonstrated an increase in the percent of dead 

fetuses per litter (80 mg/kg/d: 7.8% vs. Control: 1.9%). This increase was reported to be outside 

of the historical control range of the performing laboratory (0.74 – 6.58%). Therefore the 

LOAEL for developmental toxicity could be established as 80 mg/kg bw/d. 

This study is fully reliable (acceptable/guideline) and satisfies the requirements for a 

developmental toxicity study in rabbits when considered with the results from the rangefinding study (OPPTS 870.3700; OECD 414; Directive 87/302/EEC B.31; MAFF 12 Nousan 

8147). 

A.4.3 Reproductive Toxicity

870.3800 Reproduction and Fertility Effects - Rat

In a two-generation reproduction study (MRID 48844119), groups of Wistar [(Crl:WI) Han] rats 

(30/sex/group) received BYI 02960 in the diet (96.2%; BYI 02960-01-03) at concentrations of 0, 

100, 500, or 1800 ppm (equivalent to 0, 6.6/7.7, 32.5/38.7, and 117/137 mg/kg bw/day for P1–

M/F premating intakes; and 0/0, 6.4/7.8, 32.0/39.6, and 122.1/143.4 mg/kg bw/day for P2–M/F 
Page 64 of 116

premating intakes). The test substance was solvated in acetone prior to incorporation into the 

diet. Parental animals received the test diet for at least 70 days before the two week mating 

period. Confirmed pregnant dams then continued to receive admixed diet during gestation (22 

days) and lactation to weaning (21 days). During lactation, test substance concentrations were 

reduced by 50% to account for the corresponding increases in feed intakes of dams during this 

period. At weaning on LD 21, F1 pups (30/sex/group) were randomly selected to comprise the P2

generation and treated in the same manner as their respective P1 generation sires and dams. 

Excess F1 pups were necropsied. P2 maternal animals were retained until weaning of the 

subsequent F2 generation at LD 21. 

Under the conditions of the study, BYI 02960 produced no effects on clinical signs, gross 

necropsy findings, reproductive organs, sperm parameters, or gestation length in both 

reproductive generations. 

In parental observations, clear treatment-related decreases in mean body weight (↓10%) with 

associated reduction in body weight gain were observed at 1800 ppm in P2 females during 

premating period. Decreased food consumption was noted at 1800 ppm females in both 

generations during the pre-mating period. 

While reproductive parameters were unaffected by treatment in P1 females, a slight decrease (-

17%) in the number of estrus cycles and a slight decrease (-8%) in the total number of 

implantation sites were noted in 1800 ppm P2 females, which may be associated with the 

decreased body weights observed at the same dose. In addition, a slight reduction in epididymal 

sperm count in P1 and P2 males and in testicular sperm count in P2 males was observed at 1800 

ppm. 

In terminal observations, treatment-related histopathological changes were noted in the liver 

(centrilobular hepatocellular hypertrophy) in P1 males, and accompanied by slight (+9%) 

increases in the absolute and relative liver weights, though these changes were considered an 

adaptive effect in the context of this study. While statistically significant increases in absolute 

and relative liver weights were also noted in other 1800 ppm animals across both generations, no 

other treatment-related liver histopathological findings were observed. An increase in the relative 

thyroid weight in both P1 and P2 males was not accompanied by gross or histopathological 

change, and the toxicological significance is uncertain. 

Ovarian follicle counts in F1 females selected as P2 maternal animals were unaffected by 

treatment with the test substance. 

In fetal observations, general survival parameters were unaffected by treatment in both 

generations. A slight decrease (-15%) in overall litter size in F2 pups at 1800 ppm was noted, and 

when considered along with decreased (-8%) overall implantations in P2 dams, suggests a slight 

effect on reproductive function at 1800 ppm.

Pup body weights were unaffected by treatment at 100 ppm in both generations. Treatmentrelated and statistically significant decreases in mean body weight (-7 to -14%) and body weight

gain (-8 to -14%) were observed during the weaning period in both generations at 1800 ppm, and 
Page 65 of 116

in the F2 generation at 500 ppm. Terminal findings (necropsy, histopathology and organ weight 

analyses) did not report treatment-related effects in both generations. 

Treatment-related changes in sexual maturation were limited to slight delays in vaginal patency 

and preputial separation at 1800 ppm in F1 pups; these effects were considered secondary to 

decreased mean body weights in these animals during weaning.

The NOAEL for parental toxicity was 500 ppm (38.7 mg/kg bw/d); the LOAEL was 1800 

ppm (137 mg/kg/day) based on decreased body weight (↓10%) with associated reduced body 

weight gains in P1 females during the pre-mating period. 

The NOAEL for offspring toxicity was 100 ppm (7.7 mg/kg bw/day); LOAEL was 500 ppm 

(38.7) based on decreased body weight (-7%) in the F2 male and female pups.

The NOAEL for reproductive toxicity was 500 ppm (38.7 mg/kg bw/day); LOAEL was 1800 

ppm (137 mg/kg/day) based on a 17% lower (p<0.05) number of estrus cycles, In addition, a 

slight reduction in epididymal sperm count in P1 and P2 males and in testicular sperm count in P2

males was observed. 

This study was classified as reliable (acceptable/guideline) and satisfied the guideline 

requirements (OPPTS 870.3800; OECD N0. 416; MAFF 12 Nousan 8147) for a reproduction 

and fertility study.

A.4.4 Chronic Toxicity

870.4100a (870.4300) Chronic Toxicity – Rat

In a combined chronic/carcinogenicity study (MRID 48844123), Wistar Rj:WI (IOPS HAN) rats 

in groups of 70/sex/concentration received BYI 02960 (96.2%; 2009-000239) in the diet at 

concentrations of 0, 80, 400, or 2000 ppm daily for 52 weeks (10/sex/concentration; interim 

sacrifice) or 104 weeks (60/sex/concentration). Achieved group mean daily intakes over the 

entire study duration were 0/0, 3.17/4.48, 15.8/22.5, and 80.9/120 mg/kg bw/d for M/F, 

respectively. Following overnight fasts on study days 369 to 371 for interim sacrifice groups or 

study days 739 to 753 for carcinogenicity phase groups, all surviving animals were sacrificed by 

isoflurane inhalation.

Parameters evaluated included clinical signs, body weight, body weight gain, food consumption, 

test compound intakes, haematology, clinical chemistry, coagulation, urinalysis, ophthalmology, 

organ weights, and gross and microscopic pathology. In addition, blood samples were collected 

from five randomly selected animals from each group on study weeks 52 and 105, and analysed 

for levels of parent compound in plasma.

There was no evidence of carcinogenic potential for the test substance at the doses tested in this 

study. The incidence of premature mortality was unaffected by dosing. 

During the first year of dosing, clinical signs were confined to the 2000 ppm dose level in the 

form of increased incidences of soiled fur for both sexes, alopecia (females only), and in males 
Page 66 of 116

only, external stimuli hyper-reactivity (7% vs. 0 to 1.4% in other groups), and handling 

resistance (approx. 2 to 4-old increased incidence). All clinical signs had resolved by the second 

year of dosing with the exception of slight increased incidences of alopecia and soiled fur in 

males at 2000 ppm. In the absence of other clinical signs of toxicity, the increased incidences of 

alopecia and soiled fur were not considered toxicologically adverse findings. 

Statistically significant differences in mean body weights were confined to the 2000 ppm groups 

in both sexes, In males, a peak decrease of -7% body weight (p<0.01) at 2000 ppm compared 

with controls was noted at study week 14, with a final week 106 difference in body weight of -

6% between 2000 ppm and control animals (not statistically significant). In females at 2000 ppm, 

mean body weights were 8% lower than controls by study week 14 (p<0.01), with peak body

weight differences of -17% between 2000 ppm and control animals at week 78 and final body

weight differences of -13% terminal body weight at 2000 ppm compared with controls at study 

week 106 (p<0.01). It is likely that the decreased body weight gain may be secondary to the 

decreased food consumption observed at 2000 ppm in females. 

Ophthalmological findings at the one year examination showed an increased incidence of lens 

opacity in females at 2000 ppm relative to controls (14.3% vs. 4.3%). A small consistent increase 

in serum cholesterol in females at 2000 ppm relative to controls throughout the study was 

observed, but this change was not considered to be adverse. Plasma concentration analyses after 

both one and two years of treatment indicated a consistent relationship between increasing test 

substance administration and plasma levels of the test substance for both sexes, with a sub-linear 

relationship observed in males and an approximately linear relationship observed in females. 

At both the 52-week and 104-week scheduled sacrifices, treatment-related changes in organ 

weights were confined to increased relative (to body weight) liver weight (p<0.01 in both sexes) 

at 2000 ppm that were accompanied by liver gross and histopathological changes, including 

centrilobular hypertrophy and macrovacuolation in both sexes; eosinophilic/tigroid/mixed foci of 

hepatocellular alteration in males, and increased brown pigmentation of Kupffer cells, general 

hepatocellular brown pigmentation and interstitial mononuclear cell infiltrate in females.

Other treatment-related terminal findings reported in the study included lung findings at 104 

weeks in 2000 ppm females, comprising of increased incidence of white foci visible at necropsy. 

Lung histopathology at 2000 ppm identified lesions comprised of foamy macrophages and 

chronic interstitial and perivascular inflammation. Additionally, increased thyroid colloid 

alteration in 2000 ppm males, slightly increased frequency of follicular cell hypertrophy at 2000 

ppm in both sexes, and increased brown pigmentation of follicular cells in 2000 ppm females 

were considered treatment-related and toxicologically adverse. 

Adverse effects were not found in 400 and 80 ppm test groups.

The no-observed adverse-effect level (NOAEL) in this study was 400 ppm (15.8/22.5 mg/kg 

bw/d for M/F respectively). The LOAEL was 2000 ppm (80.9/120 mg/kg bw/d for M/F 

respectively), based on a range of in-life and terminal changes in both sexes. In-life changes 

included decreased mean body weight with associated reduction in body weight gain (both 

sexes), a slightly decreased mean food consumption rate (females only), and a slightly earlier 

onset of lens opacity (females only) during the first year of treatment. Terminal findings 
Page 67 of 116

considered included increased relative (to body weight) liver weights at study termination (both 

sexes), which were accompanied by histopathological changes in the liver (centrilobular 

hypertrophy and macrovacuolation in both sexes; eosinophilic/tigroid/mixed foci of 

hepatocellular alteration in males; increased brown pigmentation of Kupffer cells, general 

hepatocellular brown pigmentation and interstitial mononuclear cell infiltrate in females). 

Additional histopathological changes at 2000 ppm included an increased frequency in a range of 

effects in the thyroid (colloidal alteration in males, follicular hypertrophy in both sexes) and 

lungs (fomay macrophages and chronic interstitial and perivascular inflammation). 

This study is classified as fully reliable (acceptable/guideline) and satisfies guideline 

requirements for a combined chronic oral toxicity/carcinogenicity study in rats [OPPTS 

870.4300; OECD 453 (1981].

870.4100b Chronic Toxicity - Dog

In a 1-year dietary study (MRID 48844121), BYI 02960 (96.2%; batch 2009-000239) was 

administered to 5 to 6-month old beagle dogs (4/sex/dose) at concentrations of 0, 150, 300, or 

1000 ppm (0/0, 4.6/4.1, 7.8/7.8, and 28.1/28.2 mg/kg bw/d for M/F, respectively) for one year. 

Parameters evaluated included body weight, body weight gain, food consumption, test compound 

intakes, clinical signs, haematology, coagulation, clinical chemistry, urinalysis, ophthalmology, 

organ weights, and gross and microscopic pathology. In addition, after an overnight fast blood 

samples were collected from 1/sex at 0 and 300 ppm animals on study day 141 and analysed for 

test substance concentrations in plasma.

Under the conditions of this study, there were no test substance-related effects on clinical signs, 

survival, haematology, coagulation, clinical chemistry, urinalysis, ophthalmology, general 

macroscopic findings and organ weight parameters.

Changes in body weight gain were confined to females at 1000 ppm, with an 86% lower body

weight gain relative to controls in study week 1, and 17 to 66% lower relative gains over the first 

two 13-week intervals and the final 26 week interval of the study. This decreased body weight

gain resulted in terminal body weights being 9% lower in females at this dose relative to 

controls. The decreased body weight gain in females at 1000 ppm during week 1 may partially 

be linked to a 26% lower food consumption relative to controls over the same period. The 

decease decrease in absolute body weight was slight and showed no statistical significance. 

Therefore, the changes in body weight were not considered to be adverse. In addition, group 

mean food consumption was unaffected when averaged across the whole one year treatment 

period.

Blood plasma levels of BYI 02960 in animals in the 300 ppm dosing group on study day 141 

peaked at 3 hours after withdrawal of food. A slightly elevated blood plasma concentration of 

test substance was observed in males compared with females. 

Test-substance related histopathological findings were confined to myofiber degeneration in 

skeletal muscle, particularly in gastrocnemius muscle at a 50% incidence and in bicep muscle at 

75% incidence in both sexes receiving 1000 ppm diets. These lesions were of either minimal or 

slight severity (each at 1 or 2 out of a maximum severity of 5). All animals presenting with 

gastrocnemius muscle degeneration also presented with biceps femoris muscle lesions, giving a 
Page 68 of 116

total incidence for muscle histopathology of 75% in both sexes at 1000 ppm. Degeneration of the 

myofiber comprised of one or more of the following changes: atrophy, necrosis, and/or presence 

of inflammatory cells around the affected myofiber. In addition, there was a slight increase in 

ALT level.

The no-observed-adverse-effect level (NOAEL) was 300 ppm (7.8 mg kg bw/d for both 

M/F) for both sexes. The LOAEL was 1000 ppm (28.1/28.2 mg kg bw/d for M/F) for both 

sexes, based on increased incidence of minimal-to-slight, focal to multifocal areas of skeletal 

muscle degeneration in gastrocnemius and biceps femoris (75% combined incidence) in both 

sexes with associated slight increase in ALT level.

This study is fully reliable (acceptable/guideline) and satisfies the data requirements for a 

chronic toxicity study in dogs (OPPTS 870.4100; OECD 452). 

870.4200b Carcinogenicity (feeding) - Mouse

In a carcinogenicity study (MRID 48844122), C57BL/6J mice received BYI 02960 (96.2%) in

the diet at concentrations of 0, 70, 300, or 1500 ppm for 52 weeks (10/sex/concentration) or 78 

weeks (50/sex/concentration). Achieved group mean daily intakes over the entire study duration 

were 0/0, 10.0/12.2, 43/53, and 224/263 mg/kg bw/d for M/F, respectively. Parameters evaluated 

included clinical signs, body weight, body weight gain, food consumption, test compound 

intakes, haematology, ophthalmology, organ weights, gross pathology (all groups) and 

histopathology (78-week group only). In addition, blood samples were collected and analysed for 

levels of parent compound at weeks 52 and 78.

There were no treatment-related effects on survival or clinical signs of toxicity across all dose 

levels tested. No adverse effects were observed at 70 and 300 ppm.

At 1500 ppm, treatment-related decreased mean body weights (-6%/-7% for M/F) and body 

weight gain (-19%/-13% for M/F) were observed compared with controls at statistically 

significantly levels. While food consumption in 1500 ppm animals was similar to controls, with 

only marginal decreases observed in females (-2–3% vs. controls), the decreased mean body 

weight and body weight gain suggest decreased food use efficiency, and in this context, the 

changes in body weight and body weight gain are considered toxicologically adverse. However, 

the US EPA secondary reviewer considered the changes in the body weight parameters not 

approaching a magnitude of being adverse. In terminal findings at 1500 ppm, increased absolute 

and relative liver weights in males were observed and correlated to a toxicologically adverse 

change in liver histopathology (increased frequency and severity of diffuse hepatocellular 

vacuolation). Increased incidence of small/atrophic kidneys and decreased kidney weights were 

seen in 1500 ppm males. 

Based on the study findings, the NOAEL was 300 ppm (43/53 mg/kg bw/d for

males/females respectively). The LOAEL was 1500 ppm (224/263 mg/kg bw/d for 

males/females respectively), based on statistically significant increases in absolute and 

relative liver weights, with correlative liver histopathology (diffuse hepatocellular 

vacuolation) and decreased kidney weights and alterations in kidney pathology in males 

(small/atrophic kidneys).

Under the conditions of this study, no treatment-related increases in tumor incidence were 
Page 69 of 116

observed at all dose levels tested.

Blood plasma analyses indicated that the concentration of test substance in plasma scaled in an 

approximately linear manner with increasing dietary dose at both 52 and 78 week time points. 

There were minor sex differences in test substance concentrations at both time points, with males 

presenting with slightly elevated concentrations compared with females. However, no 

accumulation of test substance was noted during the study.

This study is classified as fully reliable (acceptable/guideline) and satisfies guideline 

requirements for a carcinogenicity toxicity in mice [OPPTS 870.4200; OECD 451 (1981)].

A.4.6 Mutagenicity

Gene Mutation

Guideline #: 870.5100. Bacteria reverse 

mutation test., MRID 48844124 

Acceptable/guideline

Bacteria reverse gene mutation assay using Salmonella typhimurium strains TA98, 

TA100, TA102, TA1535, TA1537 with and without an exogenous metabolic 

activation system (S9) with dose levels of 0, 3, 10, 33, 100, 333, 1000, 2500 and 

5000 μg/plate for Experiment1, and 0, 33, 100, 333, 1000, 2500 and 5000 μg/plate 

for Experiment 2. The test substance was administered to the test system as a 

solution in dimethyl sulfoxide (DMSO). Under the conditions of this study, BYI 

02960 was tested up to the limit dose (5000 μg/plate) and was negative 

In vitro mammalian cell assay

Guideline #: 870 5300. study type: Test In 

Vitro Forward Mutation assay 

(V79/HPRT)

MRID 48844128Accetable/guideline 

In a Chinese Hamster V79 cell/HPRT mutation assay, BYI 02960 (96.2% purity) 

was tested in the presence and absence of an exogenous metabolic activation system 

(S9) at concentrations of 0, 46, 92, 184, 368, 736, 1472 and 2944 g/mL for 5 hours 

(±S9) at 37C. The highest concentration level was set based on the lack of test 

substance precipitation at a concentration greater than the limit dose of 10 mM. 

Cells were then independently subcultured for assessment of cytotoxicity (cloning 

efficiency) and for expression and selection of the 6-thioguanine (2-amino-6-

mercaptopurine)-resistant phenotype. The test substance was dissolved in dimethyl 

sulfoxide (DMSO) at a maximum concentration of 300 mg/mL. Ethyl 

methanesulfonate (EMS) and dimethylbenzanthracene (DMBA) were used as 

positive controls for the non-activated and activated test systems, respectively. 

In the mutagenesis assay, visible precipitate was observed at the limit dose of 2944 

μg/mL. However, no excessive cytotoxicity was observed at any concentration tested, 

and no concentration- and treatment-related increases in mutant frequency were 

observed.

BYI 02960 was negative in the non-activated and S9-activated test systems in 

the V79/HPRT mutation assay.

In vivo cytogenetic 
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Guideline 8705385. In Vivo

micronucleus assay in mouse bone 

marrowMRID MRID 48844134 

Acceptable /guideline

In the mouse micronucleus assay, male Crl:NMRI BR mice (5/dose level) were 

administered BYI 02960 at doses of 0, 10, 20 and 40 mg/kg by two intra-peritoneal 

injections 24 hours apart, Concurrent control groups were administered corn oil (the 

vehicle (negative) control), or 20 mg/kg of cyclophosphamide (positive control). 

All animals were sacrificed 24 hours after the second i.p. injection. Bone marrow 

smears were prepared immediately after the sacrifices. In-life observations 

included clinical signs. Two thousand PCEs per animal were evaluated for 

micronuclei. 

In the main study, there were no deaths, though treatment-related toxicity was 

observed, including apathy, roughened fur, weight loss, sternal recumbency, spasm, 

periodic stretching of the body and difficulty breathing. No evidence of a cytotoxic 

effect on the bone marrow cells was observed, while the positive and vehicle 

controls induced the expected response. No statistically significant increases in 

micronucleated PCE frequency were observed in any evaluated test substancetreated group of animals. 

Under the conditions of this study, BYI 02960 was neither clastogenic nor 

aneugenic in the mouse bone marrow micronucleus assay.

A.4.7 Neurotoxicity

870.6200 Acute Neurotoxicity Screening Battery

In an acute neurotoxicity study (MRID 48844138), Wistar (Rj:WI (IOPS HAN)) rats in groups 

of 12/sex/dose received BYI 02960 (96.2%; 2009-000239) at 0, 50, 200, or 800 mg/kg bw/day as 

single oral gavage dose in methylcellulose 400 (0.5% v/v) at 10 mL/kg bw final dosing volumes. 

A follow up cohort of 12 females/dose received 0, 20, or 35 mg/kg bw/day oral gavage doses. 

Neurobehavioral parameters examined in the first cohort consisted of motor activity and 

functional observational battery (FOB) assessments at 2 hours post dosing and on Days 7 and 14 

after treatment, along with neuropathological examinations of the peripheral and central nervous 

systems at study termination. 

There were two instances of unscheduled mortality in females at 800 mg/kg bw/day, with 

animals found dead on study Days 1 (day of dosing) and Day 5, respectively. Both mortalities

were test substance related. Clinical signs prior to death in the animal found dead on study day 1

consisted of piloerection, low muscle tone and arousal, rapid respiration, tremors, myoclonic 

jerks, convulsions, dilated pupils, absence of pupil and flexor reflexes and uncoordinated or slow 

surface righting reflex. 

Effects on body weight gain were confined to 40/46% (M/F) lower mean body weight gains at 

800 mg/kg bw/day in study week 1 relative to controls that subsequently resolved such that by 

study day 14 there were no differences in group mean body weight.

Changes in FOB and activity parameters were confined to study day 1 only, with no treatmentrelated findings being present on study days 7 or 14.
Page 71 of 116

At 50 mg/kg bw/day, increased incidences of piloerection in males and females (8/12 for M and 

7/12 for F, vs. 4/12 for both M and F controls) and of dilated pupils in females (6/12, vs. 1/12 for 

controls) were observed on study day 1. 

At 200 mg/kg bw/day/day, piloerection, dilated pupils, rapid respiration, lower muscle tone, low 

arousal, repetitive licking of lips, decreased rearing, exaggerated flexor reflexes, gait 

incoordination and flattened body posture, and higher incidence of tremors were seen in both 

sexes. In addition, males from the 200 mg/kg bw/day/day dose group exhibited myoclonic jerks 

and absence of movement, and were also cold to touch, while a higher incidence of walking on 

tiptoes was observed in females at this dose. Automated measures of motor activity were reduced 

during the first 10-min interval of the session in both sexes. 

At 800 mg/kg bw/day/day, piloerection, lower muscle tone, rapid respiration, low arousal, 

tremors, myoclonic jerks, chewing, repetitive licking of lips, gait incoordination, flattened or 

hunched posture, dilated pupils, impaired (uncoordinated or slow) righting reflex, impaired 

flexor and tail pinch responses and reduced rectal temperature were observed. Automated 

measures of motor activity were also reduced in both sexes. 

In the follow-up study, the animals at 20 and 35 mg/kg showed no treatment-related effects in all 

the parameters examined.

No gross or microscopic test substance-related morphological changes were seen in the nervous 

system tissues.

The NOAEL in this acute neurotoxicity study is 35 mg/kg bw/day/day; LOAEL is 50 mg/kg 

bw/day/day based on increased incidences of piloerection in both sexes and increased 

incidence of pupil dilation in females on study day 1.

This study is fully reliable (acceptable/guideline) and satisfies the data requirements for an acute 

neurotoxicity study (OPPTS 870.6200; OECD 424).

870.6200 Subchronic Neurotoxicity Screening Battery

In a subchronic neurotoxicity feeding study (MRID 48844139), seven-to-eight week old Wistar 

Rj:WI (IOPS HAN) rats in groups of 12/sex/dose received BYI 02960 (96.2%; 2009-000239) in 

the diet at concentrations of 0, 100, 500, and 2500 ppm (0/0, 5.7/6.9, 29.4/34.8, or 143/173 

mg/kg bw/day for M/F) for 90 days. The following parameters were evaluated: body weights, 

body weight gain, food consumption, clinical signs, detailed physical examination, 

ophthalmology, and gross pathology. A neurobehavioral test battery consisting of motor activity 

and functional observational battery (FOB) assessments was conducted on all animals prior to 

BYI 02960 dosing (baseline) and during study weeks 2, 4, 8, and 13 or 14, depending on 

sacrifice schedule. On test days 92 and 93, 6 rats/sex/group were perfused in situ with fixative. 

The peripheral and central nervous systems and selected muscle tissues from perfused control 

and high dose groups were prepared for histological evaluation.

Under the conditions of the study, there were no test substance-related effects on the following 

parameters: mortality, ophthalmology, neurobehavioral parameters (FOB and motor activity), or 

gross and microscopic morphology of the nervous system in either male or female rats of any 
Page 72 of 116

dose groups.

There was a decrease in absolute body weight in males and females at 2500 ppm reaching 9% at 

week 1 for females and at weeks 4 and 8 for males. The magnitude of reduced body weight did 

not persist or approach the level of being adverse. Associated mean body weight gains were also 

decreased for both sexes at 2500 ppm relative to controls from study week 1 onwards.

There were decreases in food consumptions in 2500 ppm males and female (↓18/29% (M/F)

p<0.01) over study week 1, which partially recovered over the study to reach a 9/4% (M/F) lower 

consumption relative to controls on study week 13. 

In this 90-day neurotoxicity study with dietary administration, flupyradifurone did not 

produce neurotoxicity at any dose levels tested. The no-observed-adverse-effect level 

(NOAEL) was 500 ppm (29.4/34.8 mg/kg bw/day; M/F); LOAEL was 2500 ppm (143/147 

mg/kg bw/day; M/F) based on decreased food consumption with associated slight decrease 

in absolute body weight.

This study is classified as fully reliable (acceptable/guideline) and meets the guideline 

requirements of subchronic neurotoxicity study (U.S. EPA OPPTS 870.6200; OECD 424; and 

MAFF Japan Nousan 8147). 

870.6300 Developmental Neurotoxicity Study

In a developmental neurotoxicity study (MRID 48844140), groups of time-mated 12-week old 

female Wistar Han CRL:WI (HAN) (30/dose group) received acetone-solvated BYI 02960 

(96.2%; 2009-000239) in the diet at concentrations of 0, 120, 500, or 1200 ppm (0, 10.3, 42.4, or 

102 mg/kg bw/day) from gestation day (GD) 6 to lactation day (LD) 21. For dams, the following 

parameters were evaluated: body weight, body weight gain, food consumption, mortality, clinical 

signs, detailed physical examination, FOB examination (GD 13 and 20 and LD 11 and 21), and 

reproductive outcomes. For pups, neurobehavioral evaluations including learning tasks (passive 

avoidance and the water maze test), motor activities, and FOB parameters were evaluated 

throughout the post-natal period. Additional pup parameters evaluated included body weight, 

food consumption, ophthalmology, sexual maturation, brain weights, gross necropsy, and neural 

and muscle tissue histopathological and morphometric analyses.

Under the conditions of this study, for dams, there were no test substance-related effects on 

maternal clinical signs, FOB parameters, mortality, or reproductive outcomes. For offspring, 

there were no test substance related effects on clinical signs, mortality, acquisition and retention 

parameters for the passive avoidance and water maze tasks, sexual maturation, surface righting, 

pupil reflex or other ophthalmology parameters, necropsy findings, organ weights, macroscopic 

or histological brain morphometry, or brain or peripheral nerve histopathology. 

During gestation, a decrease in body weight was seen (↓7%) in 1200 ppm dams and associated 

decreases in body weight gain were present. At lactation period a decrease of (4% to 6 %) in 

body weight was also found in1200 ppm dams. A slight decrease in food consumption was found 

in the dames at various times during the gestation and lactation periods (ranging from 1% to 

8%). However, these changes were slight and not considered as adverse. 
Page 73 of 116

For pups, a non-statistically significant increase in both motor and locomotor activity was seen in 

males at 1200 ppm on PND 13 relative to concurrent controls. On PND 60, startle amplitude for 

all 50 trials was statistically significantly (p<0.05) increased by approx. 2-fold in females at 1200 

ppm relative to controls. 

There was no evidence of treatment-related changes in brain morphometry or peripheral nerve 

histopathology.

Under the conditions of this study, the maternal NOAEL was established at 1200 ppm (102 

mg/kg/day) based on no adverse effects were found in the dams at the highest dose tested.

The offspring NOAEL was 500 ppm (42.4 mg/kg/day); LOAEL was 1200 ppm (102 mg/kg/day) 

based on statistically significant persistent increased in startle response amplitude.

This study is reliable (acceptable/guideline) and satisfies the requirements for a developmental 

neurotoxicity study in rats (OPPTS 870.6300; OECD 426).

A.4.8 Metabolism

870.7485 Metabolism – Rat

A. Pyridinylmethyl14C

In a toxicokinetic and metabolism study (MRID 48844141), groups of 4 Wistar rats per sex per 

dose were administered by oral gavage a single dose of 2 or 200 mg/kg bw [Pyridinylmethyl14C]BYI02960 in 0.5% aqueous Tragacanth® and sacrificed by exsanguination under anaesthesia 

at 72 hours post dosing. An additional group of 4 male Wistar rats were administered by i.v. a 

single dose of [Pyridinylmethyl14C]BYI02960 (2 mg/kg bw) in the same vehicle and sacrificed 

at the same time post dosing. The test compound was radiolabeled with 14C in the 

pyridinylmethyl bridge of the molecule. The metabolism and radioactivity which included the 

test compound and metabolites was determined in urine and faecal samples collected for the time 

range between dosing and sacrifice. Additionally, radioactivity in plasma micro samples was 

determined over the study period (17 time points). Total radioactivity was determined in excreta 

and in organs and tissues collected at sacrifice. Samples were analysed, and parent compound 

and metabolites identified, by radiochromatographic (HPLC, TLC) and spectroscopic (LC/MS) 

methods.

Mean total radioactivity was nearly quantitative since approximately 91 to 103% of the 

administered dose was found in the excreta and in the bodies of animals at sacrifice.

[Pyridinylmethyl14C]BYI 02960 was nearly completely absorbed after oral administration, 

which was demonstrated by the high factor of bioavailability (F = 0.93) calculated from the 

plasma data of low dose tests after oral and i.v. administration, and that approximately 76 to 90% 

of the administered radioactivity were detected in the urine and in the bodies without GIT at 

sacrifice of male and female rats. The absorption started immediately after dosing as could be 

seen from the quick increase of radioactivity in plasma micro samples, with the peak plasma 
Page 74 of 116

concentration (Cmax) reached approximately 1 hour after administration in the low dose tests and 

within approximately 2 to 4 hours in the high dose tests. 

The distribution of the radioactivity within the body was fast. From the maximum plasma level 

(Cmax), the radioactivity level declined slowly down to approximately 50% of Cmax after 4 – 8 

hours in the low dose tests and after 8 – 24 hours in the high dose tests and down to low values 

around the LOQ in the low dose tests and to approximately 0.5% of Cmax in the high dose tests 

by study termination (72 hours). 

Excretion was rapid, mainly by the renal route and essentially complete by 72 hours post dosing. 

Female rats exhibited slightly higher renal excretion rates of approximately 86% and 90% of the 

administered dose compared to approximately 76% of the dose in males. The major part of the 

dose detected in urine (>84%) was excreted within 24 hours after treatment and was ongoing up 

to 72 hours. Faecal excretion accounted for approximately 23 – 26% of the total administered in 

males, and 7 – 10% in females. At the time of sacrifice, 72 hours after administration, the 

radioactive residues in organs and tissues were low, and only trace amounts of approx. <0.1 –

0.3% of the total administered dose was detected in the body and in the GIT. Most of the 

residues of the low dose tests were lower than 0.01 mg/kg sample. The highest concentrations of 

the low dose tests, but also at a low level of approximately ≤0.018 mg/kg sample were detected 

in blood cells, the GIT and in the eyes of female rats. The residues of the low and high dose tests 

were nearly proportional to the dose.

Parent compound, three major (BYI 02960-OH, BYI 02960-6-CNA and BYI 02960-hippuric 

acid) and five minor metabolites were isolated from urine and four of them identified by 

spectroscopic methods (LC-MS and 1H-NMR and 2D-NMR), HPLC and/or TLC cochromatography or comparison. Identification rates were high in excreta, and amounted to 83% 

to 94% of the total administered radioactivity. Parent compound represented the predominant 

part of the radioactivity in urine of male and female rats. In faeces samples of male rats, the 

metabolite BYI 02960-OH was more prominent than the parent compound. Two metabolites, 

BYI 02960-6-CNA and BYI 02960-hippuric acid were also prominent metabolites in male rats 

but not in females. In total further 19 unknown metabolites were characterised by their

chromatographic behaviour. All of them were detected at trace amounts of approximately <0.1% 

to 0.9% of the dose. The metabolic profiles in urine and faeces were very similar for both sexes 

but male rats exhibited a higher rate of metabolite formation compared to female animals. The 

metabolic transformation of BYI 02960 was principally oxidative and took place at least at 3 

different structural positions of the test compound.

The principal metabolic reactions of [pyridinylmethyl-14C]BYI 02960 in rats were: (1) 

hydroxylation followed by conjugation with glucuronic acid to or with sulphate; (2) cleavage of 

the difluoroethyl group forming BYI 02960-des-difluoroethyl; and cleavage of the molecule at 

the pyridinylmethyl bridge forming BYI 02960-6-CNA, which was further conjugated with 

glycine to BYI 02960-hippuric acid.

The results of the toxicokinetic and metabolism study were in good accordance with those 

obtained in other studies performed with different radiolabels: [Ethyl-1-

14C]BYI 02960 (Weber, 

2011a; Study No. M1824567-3, Koester, 2012a; Study No. M1824575-2) and [Furanone-4-
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14C]BYI 02960 (Weber, 2011b; Study No.M1824560-6, Koester, 2012a; Study No. M1824574-

1, Koester, 2011b, Study No. M1821760-5). 

This study is fully reliable (acceptable/guideline) and satisfies the study requirements of a 

metabolism study (U.S. EPA 870.7485; OECD Section 4 Part 417 and Annex to Directive 

87/302/EEC, Part B, Toxicokinetic; JMAFF 12 Nousan 8147).

B. furanone-4-

14C

In a toxicokinetic and metabolism study (MRID 48844143), a group of 4 male and 4 female 

Wistar rats were administered by oral gavage a single dose of 2 mg/kg bw [furanone-4-

14C]BYI 

02960 in 0.5% aqueous Tragacanth® and sacrificed by exsanguination under anaesthesia at 168 

hours post dosing. The test compound was radiolabeled with 14C in the C4-position of the 

furanone ring of the molecule. The metabolism and radioactivity which included the test 

compound and metabolites was determined in urine and faecal samples collected for the time 

range between dosing and sacrifice. Additionally, radioactivity in plasma micro samples was 

determined over the study period (23 time points). Total radioactivity was determined in excreta 

and in organs and tissues collected at sacrifice. Samples were analysed, and parent compound 

and metabolites identified, by radiochromatographic (HPLC, TLC) and spectroscopic (LCMS) 

methods.

Mean total radioactivity recovery was nearly quantitative since approximately 96% and 102% of 

the administered dose were found in the excreta and bodies of males and females respectively at 

sacrifice. 

[Furanone-4-14C]BYI 02960 was nearly completely absorbed since >79% and >91% of the total 

dose administered was detected in the urines and the bodies without GIT at sacrifice of male and 

female rats respectively. The absorption started immediately after dosing as could be seen from 

the quick increase of radioactivity in plasma micro samples, with the peak plasma concentration 

(Cmax) was reached approximately 1.5 hours after administration in both sexes.

The distribution of the radioactivity within the body was fast. From the maximum plasma level 

(Cmax), the radioactivity level declined slowly down to approximately 50% of Cmax after 8 hours 

in both sexes and <1% of Cmax 72h after dosing.

Excretion was rapid and mainly by the renal route. Approximately 79% of the total dose 

administered was found the urine of male rats and approximately 91% in the urine of female rats. 

The major part of the dose was excreted within 24 hours after treatment, for male and female 

rats. At the time of sacrifice, 168 hours after administration, a small proportion of approximately 

0.5% of the dose administered for males and approximately 0.2% for females were still detected 

in the body without GIT.

The parent compound was moderately metabolised to approximately 20 metabolites in total, 

consisting of one major (BYI 02960-OH) and six minor metabolites of an isolated and purified 

compound. Identification rates were >84% of the total dose administered in male rats and >95% 

in females. Another approximate 8% of the dose in males and 4% in females were characterised 

by their chromatographic behaviour but not identified. All metabolites accounting for >1% of the 

dose administered were identified except a polar metabolite fraction accounting for 5.30% in 
Page 76 of 116

males and 2.45% in females. It is considered that this polar fraction is most likely represented by 

biomolecules. Parent compound represented the predominant part of the radioactivity in urine 

but in faeces samples the metabolite BYI 02960-OH was more prominent. 

Overall, male rats showed a higher rate of metabolism with only approximately 55% of 

unchanged parent compound found in excreta whereas 76% of unchanged BYI 02960 was found 

in the excreta of female rats, though the metabolic patterns were very similar in males and 

females.

The principal metabolic reactions of [furanone-4-

14C]BYI 02960 in rats were: (1) hydroxylation 

followed by conjugation with glucuronic acid or with sulphate; (2) cleavage of the difluoroethyl 

group forming BYI 02960-desdifluoroethyl; (3) cleavage of the molecule at the pyridinylmethyl 

bridge forming BYI 02960-difluoroethyl-amino-furanone; and (4) cleavage of molecule at the 

nitrogen-carbon bond next to the furanone moiety followed by further conversion to C1 and C2 

compounds of the natural pool including complete degradation to carbon dioxide.

Male rats exhibited a higher proportion of the polar metabolite fraction and higher residues in the 

body at the time of sacrifice, and also exhibited a higher proportion of radioactivity in exhaled 

air in a study with [pyridinylmethyl14C]BYI 02960 (Koester 2011a). All these observations 

taken together suggest that the furanone-4-

14C radiolabel is not completely stable and that a small 

part of the dose obviously underwent extensive biotransformation to C1- and C2-fragments that 

resulted in an incorporation of radioactivity into biomolecules, in particular in male rats.

The results of these metabolism investigations are in good accordance with those obtained from 

the corresponding organ metabolism rat study with [furanone-4-

14C]BYI 02960 (Koester, 

2012b). 

This study is fully reliable (acceptable/guideline) and satisfies the study requirements of a 

metabolism study (U.S. EPA 870.7485; OECD Section 4 Part 417 and Annex to Directive 

87/302/EEC, Part B, Toxicokinetic; JMAFF 12 Nousan 8147).

C. Ethyl-1-

14C

In a toxicokinetic and metabolism study (MRID 48844146), a group of 4 male Wistar rats were 

administered by oral gavage a single dose of 2 mg/kg bw [Ethyl-1-

14C]BYI02960 in 0.5% 

aqueous Tragacanth® and sacrificed by exsanguination under anaesthesia at 72 hours post 

dosing. The test compound was radiolabeled with 14C in the C1-position of the ethyl side chain 

of the molecule. The metabolism and radioactivity which included the test compound and 

metabolites was determined in urine and faecal samples collected for the time range between 

dosing and sacrifice. Additionally, radioactivity in plasma micro samples was determined over 

the study period (23 time points). Total radioactivity was determined in excreta (including 

expired air) and in organs and tissues collected at sacrifice. Samples were analysed, and parent 

compound and metabolites identified, by radiochromatographic (HPLC, TLC) and spectroscopic 

(LCMS) methods.

Mean total radioactivity recovery was nearly quantitative since approximately 100% of the 

administered dose was found in the excreta and bodies of males at sacrifice. 
Page 77 of 116

[Ethyl-1-

14C]BYI02960 was nearly completely absorbed since >85% of the total dose 

administered was detected in the urine and the body without GIT at sacrifice. The absorption 

started immediately after dosing as could be seen from the quick increase of radioactivity in 

plasma micro samples, with the peak plasma concentration (Cmax) was reached approximately 1 

hour after administration. 

The distribution of the radioactivity within the body was fast. From the maximum plasma level 

(Cmax), the radioactivity level declined slowly down to approximately 50% of Cmax within 8 

hours and to approximately 8% of Cmax 72h after dosing.

Excretion was rapid and mainly by the renal route. Approximately 82% of the total administered 

dose was excreted in the urine and approximately 14% in the faeces. Only a negligible part of 

0.2% of the total administered dose was detected in expired air. The major part of the dose 

(>87%) was excreted within 24 hours after treatment, though excretion was ongoing in the time 

range between 24 and 72 hours the time of sacrifice. In particular, the major part of the 

metabolite BYI 02960-DFA was excreted on day 2 and day 3. At the time of sacrifice, 72 hours 

after administration, a small proportion of approximately 3% of the total dose administered was 

still detected in the body without GIT. The residue was highest in plasma with 0.158 mg/kg 

sample. For most other organs and tissues, levels were in the range between 0.05 and 0.1 mg/kg 

sample.

Parent compound, one major (BYI 02960-OH) and five minor metabolites were identified by 

HPLC and/or TLC co-chromatography or comparison. The label specific metabolite BYI 02960-

DFA was additionally identified by high resolution LC/MS of the isolated compound. 

Identification rates were >95% of the total radioactivity in urine and >85% of the total 

radioactivity in faeces. Parent compound represented the predominant part of the radioactivity in 

urine but in faeces samples the metabolite BYI 02960-OH was more prominent. Approximately 

92% of the total dose administered was identified in excreta. Another approximate 3% of the 

dose corresponding to 6 unknown metabolites were characterised by their chromatographic 

behaviour. All metabolites representing >1% of the dose administered have been identified.

The principal metabolic reactions of [ethyl-1-14C]BYI 02960 in rats were: (1) hydroxylation 

followed by conjugation with glucuronic acid; (2) cleavage of the difluoroethyl group leading to 

BYI 02960-DFA; and (3) cleavage of the molecule at the pyridinylmethyl bridge leading to BYI 

02960-difluoroethyl-amino-furanone.

The results of the metabolism investigations are in good accordance with those obtained from the 

corresponding organ metabolism rat study with [ethyl-1-14C]BYI 02960 (Koester, 2012a).

This study is fully reliable (acceptable/guideline) and satisfies the study requirements of a 

metabolism study (U.S. EPA 870.7485; OECD Section 4 Part 417 and Annex to Directive 

87/302/EEC, Part B, Toxicokinetic; JMAFF 12 Nousan 8147).

870.7600 Dermal Absorption – Rat

Dermal absorption study with technical grade active ingredient was not conducted. Triple 

pack dermal penetration studies were conducted with the SL formulation.
Page 78 of 116

A. In vivo dermal absorption with SL formulation 

In an in vivo dermal absorption study with a [pyridinylmethyl14C]-BYI02960 200g/L soluble 

concentrate (SL) formulation, 7 to 9 week-old male Wistar Rj: WI (IOPS HAN) rats in groups of 

4/concentration/timepoint (MRID 48844557) over four sacrifice timepoints of 8, 24, 72, or 168 

hours received either the undiluted 200 g/L SL formulation, or 0.625 g/L or 0.1 g/L aqueous 

dilutions for eight hours. Absorption was followed using [14C]-BYI02960, which was uniformly 

blended into the formulations prior to application. Animals were lightly anaesthetised by an 

unspecified method and two plastic ‘protective saddles’ were secured to define the application 

site for the test substance The formulated products were then applied dose to a 2 x 6 cm2shaved 

area of dorsal skin as two aliquots of 60 L (total of 120 L) to each animal in the 12 groups (N 

= 4/group), and the exposed skin area and protective saddles were covered in perforated plastic 

as a semi-occluded cover not touching the skin, and held in place over the saddles with surgical 

tape (~3 x 4 cm). After eight hours, covers, saddles, and tape were removed and wiped down by 

swabs and distilled water. The application sites were swabbed with 1% v/v Tween 80 in PBS 

until no more radioactivity was detected. If necessary, the treated skin was shaved with the 

shavings being retained for analysis. The skin was then tape stripped until the epidermis 

appeared shiny. The 8 hour sampling group animals were sacrificed, while animals retained for 

the subsequent timepoints received new protective saddles and covers. 

Urine, feces, and cage wash samples were collected individually at 0 to 8, 8 to 24, and 24-hour 

intervals thereafter up to the time of final sacrifice. At sacrifice, animals were subjected to 

terminal anesthesia by isoflurane, and exsanguinated via cardiac puncture. Application site skin, 

surrounding skin (within 1 cm perimeter, distant skin, and cardiac blood were collected, and 

along with skin swabs, tape strips, covers, saddle, and tape were retained for analysis of 

radioactivity by LSC using a Packard 1900 TR counter. 

Non-absorbed dose was regarded to consist of radiolabel in dressings, surface tape strips (first 

two strips), and fur. Radiolabel in urine, feces, cage washes, non-treated skin and carcass was 

regarded as being directly absorbed. Radiolabel in stratum corneum, and skin, including 

surrounding skin were regarded as being potentially absorbable. 

For the 200 g/L neat product, the mean total absorbable fractions were 21.78, 19.63, 17.00, and 

19.18% of the applied dose for the 8, 24, 72, and 168 hour groups, respectively. Of these totals, 

the directly absorbed component was 2.27, 3.88, 4.39, and 8.14% of total applied dose, 

respectively. The test substance readily distributed to the surrounding skin, reaching 15.16% of 

total applied dose at 8 hours, and steadily falling to reach 7.69% of total applied dose by 168 

hours. The fraction in the non-treated skin reached a maximum of 2.71% of applied dose at 72 

hours, falling to 2.3% of applied dose at 168 hours. The proportion in the stratum corneum 

varied over time, being 1.05% at 8 hours, reaching a maximum of 4.14% of total applied dose at 

24 hours, falling to 0.71% of applied dose at 72 hours, and increasing to 1.34% at 168 hours. The 

urine was the predominant route of excretion, containing a mean total of 2.18% of applied dose 

at 168 hours, while faeces contained a mean total of 0.94%. Mean total radiolabel recovery 

ranged from 101.1 to 113.4% of that applied dose for the 8, 24, 72, and 168 hour sacrifice groups 

respectively.
Page 79 of 116

For the 0.625 g/L diluted product, the mean total absorbable fractions were 9.26, 8.28, 9.66, 

and 5.53% for the 8, 24, 72, and 168 hour exposure groups, respectively. Of these totals, the 

directly absorbed component was 2.21, 1.31, 2.18, and 2.24% of total applied dose, respectively. 

In contrast to the 200 g/L undiluted formulation, distribution to the surrounding skin was 

minimal, being only 0.307% of total applied dose at 8 hours, 0.345% at 24 hours and rising to 

0.577% at 72 hours, and falling to reach 0.154% of total applied dose by 168 hours. The 

proportion in the non-treated skin was also far lower than that obtained with the 200 g/L 

formulation, reaching a maximum of 0.473% of applied dose at 72 hours, and falling to 0.198% 

of applied dose at 168 hours. The proportion in the stratum corneum was 4.86% at 8 hours and 

5.96% at 24 hours, reaching a maximum at 72 hours of 6.41% of applied dose, and falling to 

2.71% at 168 hours. The urine was the predominant route of excretion, containing a mean total 

of 1.10% of applied dose at 168 hours, while faeces contained a mean total of 0.3%. Mean total 

radiolabel recovery was 99.84, 99.36, 92.30, and 95.59% of total applied dose at the 8, 24, 72, 

and 168 hour sacrifice groups, respectively.

For the 0.1 g/L diluted product, the mean total absorbable fractions were 16.64, 10.32, 18.20, 

and 20.57% for the 8, 24, 72, and 168 hour exposure groups, respectively. Of these totals, the 

directly absorbed component was 4.32, 2.78, 5.28, and 8.12% of total applied dose, respectively. 

Similar to the 0.625 g/L formulation and in contrast to the 200 g/L formulation, distribution to 

the surrounding skin was low, being 1.53% of total applied dose at 8 hours, 0.410% at 24 hours, 

0.400% at 72 hours, and rising slightly to 0.734% of total applied dose by 168 hours. The 

proportion in the non-treated skin was between the relatively low levels for the 0.625 g/L 

formulation and the high levels of the 200 g/L formulations, with a maximum of 1.551% at 8 

hours, and falling to 0.794% of applied dose at 168 hours. The proportion in the stratum corneum 

was 8.74% at 8 hours and 6.26% at 24 hours, and as with the other concentrations, maximum 

levels were reached at 72 hours, at 11.69% of applied dose, and falling to slightly to 10.37% at 

168 hours. The relative level of total applied dose in the stratum corneum at 168 hours was 

therefore 3.8-fold and 7.7-fold higher than those obtained with the 0.625 g/L and 200 g/L 

formulations, respectively. The urine was again the predominant route of excretion, containing a 

mean total of 3.00% of applied dose at 168 hours, while faeces contained a mean total of 0.443% 

for this timepoint. Mean total radiolabel recovery was 100.5, 95.8, 102.9, and 95.6% of total 

applied dose at the 8, 24, 72, and 168 hour sacrifice groups, respectively.

The last available layers of stratum corneum (tape strips 12 or 9) for the animals with the highest 

absorption values in each of the three 168 hour concentration groups all contained radiolabel, 

albeit at levels 32 to 64% lower than that on the first (surface) tape strips. When considered with 

the observed urinary excretion of radiolabel at 168 hour study termination, this finding 

demonstrated that dermal absorption of applied test material was potentially continuing up to and 

including the 168 hour timepoint.

The study authors stated that as a conservative estimate, the amount of BYI 02960 potentially 

absorbable following an 8-hour exposure ranged from 17.0 to 21.8% for the 200 g/L neat 

product, 5.54% to 9.66% for the 0.625 g/L intermediate dilution, and from 10.3% to 20.6% for 

the highly diluted 0.1 g/L formulation, based on group mean values.

The evaluator has considered that, due to the basis of high intragroup variability (standard 

deviation exceeding 25% of the mean), individuals in each group with the highest levels of 
Page 80 of 116

dermal absorption were considered to be more representative of potential intraspecies variation 

compared to group means. On an individual animal basis, the highest absorptions of test 

substance were 29.9, 9.38, and 23.9% for the concentrate, 0.625 g/L, and 0.1 g/L dilutions, 

respectively.

In summary, following an 8-hour in vivo dermal exposure to [pyridinylmethyl14C]-

BYI02960 200g/L SL formulation and dilutions, the maximal absorbable dose was 29.9, 

9.38, and 23.9% for 200 g/L (neat), 0.625 g/L, and 0.1 g/L dilutions, respectively. The 

dermal absorption data from both in vivo and in vitro dermal absorption studies were used 

to estimate the in vivo dermal absorption factor for humans; the estimated factors were 

42.1, 3.32 and 17.2% for BYI02960 200g/L SL concentrate, 0.625 g/L, and 0.1 g/L dilutions, 

respectively. 

This study is reliable (acceptable) and meets the data requirements for an in vivo dermal 

absorption study (OECD TG 427 [2004]).

B. In vitro dermal penetration study with rat and human skin

The dermal penetration of a BYI02960 200g/L soluble concentrate (SL) formulation was tested 

in vitro using rat (dorsal) and human (abdominal) skin mounted in a glass flow-through diffusion 

cell system with an exposure area of 1 cm2 maintained at 32+2oC (MRID 48844558). The test 

substance was applied as either the undiluted 200 g/L SL formulation, or as 0.625 g/L or 0.1 g/L 

aqueous dilutions. Penetration and absorption were followed using [pyridinylmethyl14C]-

BYI02960, which was uniformly blended into the formulations prior to application. 

The formulated products were applied at a rate of 10 μL/cm2 to 2 groups of 6 skins per dose level 

per species with the exception of the 0.625 g/L groups which had only 5 skins for humans and 4 

for rats. The achieved concentrations of BYI02960 applied per area of skin was approximately 

1800 to 2000, 4.5 to 5.0, and 0.9 to 1.1 μg/cm2 for the 200, 0.625 and 0.1 g/L formulations, 

respectively. The formulation concentrations and application rates were designed to mimic 

potential field-use exposures. The applied formulation remained in contact with the skins for 8 

hours. Serial receptor fluid samples (2×50 μL) were collected hourly for the 24 hour duration of 

the study. The volume of receptor fluid was maintained by the replacement with a volume of 

fresh receptor fluid, equal to the total aliquot volume. At 8 hours, the skin surfaces of all groups 

were washed with sponge swabs and freshly prepared 1% v/v Tween 80 in phosphate buffered 

saline. At 24 hours, the skin samples were swabbed again, and stripped using Monaderm 

adhesive tape to remove non-absorbed surface test material (first two strips) and stratum 

corneum (strips three until a shiny appearance had been reached, indicating complete removal). 

Stripping involved applying the tape for five seconds before removing the strip against the 

direction of hair growth.

For the 200 g/L formulation, mean total recovery was 106.1 and 105.5% of that applied for 

humans and rats, respectively. As a percentage of total applied dose, the potentially absorbable 

fraction (receptor fluid plus tape-stripped skin) over 24 hours was 0.204 and 0.145% for human 

and rat skin, respectively. The total absorbable dose was therefore approx. 1.4-fold greater for 

human skin than for rat skin. Of the potentially absorbable fraction, directly absorbed dose 

(receptor fluid and receptor fluid terminal) only comprised 0.016±0.029% and 0.071±0.071% of 

the total applied for human and rat skin, respectively. Stratum corneum contained just over half 
Page 81 of 116

(0.103±0.120%) of the total absorbable fraction in humans, and just over a third (0.055±0.075%) 

of the total absorbable for rats. Washing the skin at eight hours removed >105% of the applied 

dose for both species, while tape strips one and two at 24 hours removed 0.128 and 0.132% of 

the applied dose for human and rat skin, respectively.

For the 0.625 g/L formulation, mean total recovery was 100.3 and 96.4% of that applied for 

humans and rats, respectively. As a percentage of total applied dose, the potentially absorbable 

fraction (receptor fluid plus tape-stripped skin) over 24 hours was 2.008 and 5.667% for human 

and rat skin, respectively. The total absorbable dose was therefore approx. 2.5-fold greater for rat 

skin than for human skin. As was found for the concentrate formulation, directly absorbed dose 

(receptor fluid and receptor fluid terminal) was a minor contributor to the potentially absorbable 

total, being 0.392±0.344% and 1.075±0.330% for human and rat skin, respectively. Stratum 

corneum again contained just over half of the total absorbable fraction for both humans 

(1.149±0.534%) and rats (2.852±3.832%). Washing the skin at eight hours removed a mean of 

97% and 85.5% of the applied dose for human and rat skin samples, respectively. Tape strips one 

and two at 24 hours removed 0.492 and 2.137% of the applied dose for human and rat skin, 

respectively.

For the 0.1 g/L formulation, mean total recovery was 106.1 and 105.5% of that applied for 

humans and rats, respectively. As a percentage of total applied dose, the potentially absorbable 

fraction (receptor fluid plus tape-stripped skin) over 24 hours was 4.753±2.963% and 

6.607±2.796% for human and rat skin, respectively. The extent of interspecies difference at this 

concentration was therefore similar in magnitude to that for the concentrate, but in reverse 

direction, being only 1.4-fold higher for rat skin than for human skin. As was found for the two 

higher concentration levels, directly absorbed dose (receptor fluid and receptor fluid terminal) 

was a minor contributor to the potentially absorbable total, being 0.646±0.482% and 

1.105±0.436% for human and rat skin, respectively. Stratum corneum again contained just over 

half of the total absorbable fraction for humans (2.998±1.828%) but was even higher for rats, 

comprising approx. two-thirds (4.409±2.893%) of the total. Washing the skin at eight hours 

removed a mean of 89.4% and 85.5% of the applied dose for human and rat skin samples, 

respectively. Tape strips one and two at 24 hours removed 0.99% and 5.86% of the applied dose 

for human and rat skin, respectively.

As penetration into the receptor chamber remained ongoing at the 24 hour termination point of 

the study for the majority of rat and human skin samples for the three formulation 

concentrations, test substance remaining in the stratum corneum were considered to be 

potentially absorbable.

Group mean values were used in the calculations of absorbable dose. Although standard 

deviations for the potentially absorbable fractions in all groups ranged from 42% (rat 0.1 g/L 

sample) to 106% (human 200 g/L sample) of the means, the variations were considered likely to 

be outliers arising from experimental variation/errors rather than representations of true 

biological variation.

Under the conditions of this in vitro dermal absorption study, the study author calculated the 

mean total potentially absorbable values in humans/rat skin samples, respectively, over 24 hours 
Page 82 of 116

to be 0.20/0.15% for the 200 g/L formulation, 2.0/5.7% for the 0.625 g/L formulation, and 

4.8/6.6% for the 0.1 g/L formulation. The evaluator agreed with the study author’s conclusions.

The results obtained in this study, using an in vitro flow-through diffusion cell system, 

demonstrate that penetration and absorption of BYI02960 from the 200 g/L SL formulation was 

relatively equivalent to within 30 to 40% ranges in rat and human skin when applied as the 

undiluted concentrate or highly diluted (0.1 g/L) formulations, but that dermal absorption was 

nearly 3-fold higher in rats for the intermediate dilution (0.625 g/L). 

The in vitro dermal absorption data on isolated rat and human skin in combination with 

the in vivo rat dermal absorption data were used by the primary study evaluator to 

estimate the in vivo human dermal absorption factor; the factors were 42.1%, 3.32%, and 

17.2% for the concentrate, intermediate, and highly diluted formulation, respectively.

However, US EPA secondary reviewer does not agree with the conclusion concerning the 

human dermal absorption factor because there are no data for the exposure duration 

beyond 24 hours in the in-vitro human and rat skin studies. Therefore, the US EPA 

determines that the appropriate estimate for the potential human dermal absorption factor 

to be 7.42 % based on the data on the 24-hour exposure period and most dilute 

administered concentration (0.1 g/l). 

This study is reliable (Acceptable) and fulfils the requirements of the OECD guideline for 

in vitro dermal absorption studies in rats and humans (OECD 428 (2004)). 

A.4.9 Immunotoxicity

870.7800 Immunotoxicity

In an immunotoxicity study (MRID 48844148), BYI 02960 (96.2% a.i. batch# 2009-000239) 

was administered to seven week old female Wistar, Rj:WI (IOPS HAN) rats in groups of 10/dose 

at concentrations of 0, 125, 600, or 3000 ppm (0, 10, 50, or 230 mg/kg bw/d) for 30 days. A 

positive control group consisting of 10 female Wistar, Rj:WI (IOPS HAN) rats received oral 

gavage doses of 3.5 mg/kg bw/d cyclophosphamide at 5 mL/kg bw dosing volumes for 28 days.

On Day 26, the test animals were immunized with an injection of sheep red blood cells (SRBC). 

On study Day 30, blood samples were collected from the test animals and serum samples were 

assayed for their concentration of SRBC-specific IgM antibodies to provide a quantitative 

assessment of humoral immune response by ELISA. Additional parameters that were evaluated 

include mortality, clinical signs of toxicity, body weight, body weight gain, food consumption, 

selected organ weights (i.e. spleen, and thymus), and macroscopic examination of all major 

organs, tissues and body cavities.

There were no observable test substance related clinical signs, and premature mortality was 

confined to euthanasia of one animal at 600 ppm due to forelimb automutilation on study day 8. 

As this was unaccompanied by other necropsy findings, it was considered unrelated to the test 

substance.

Overall group mean body weight gains at 3000 ppm over study days 1 to 29 were 23% lower 

than that in controls (p<0.05), resulting in 6% lower mean terminal body weight than controls 
Page 83 of 116

without statistical significance (p > 0.05). Decreases in food consumption of ≤ 34% (week 1) 

relative to controls were seen at 3000 ppm throughout the study period and were likely linked to 

changes observed in body weight gain. 

Necropsy findings in negative control and test substance groups were unremarkable, whereas 

atrophied and/or small (5 or 6/10 animals) spleens were observed in cyclophosphamide-dosed 

positive control animals.

While there was a dose-related decreasing trend in absolute spleen weights relative to controls in 

treated animals (2%, 4% and 6% decreases at 125, 600 and 3000 ppm respectively), relative (to 

body weight) spleen weights were essentially unchanged at 3000 ppm (+1% increase). Similarly, 

absolute thymus weights at 3000 ppm were decreased by 4% relative to controls, but relative (to 

body weight) thyroid weights were unaffected. Positive control animals had 32 to 34% (p≤0.01) 

decreases in mean absolute and relative spleen weights, and 27 to 28% (p≤0.01) decreases in 

absolute and relative thymus weights, respectively.

The SRBC-specific IgM ELISA data showed a 55% increase from controls at 125 ppm, 15% 

decrease at 600 ppm, and an 18% decrease at 3000 ppm, with no findings being statistically 

significant (p>0.05). Based on the lack of dose dependency and absence of statistical 

significance, overall there were no indications of test substance immunosuppressive potential up 

to and including the highest dose tested of 3000 ppm (~230 mg/kg bw/d). The positive control 

performed as expected, with a 93% decrease (p<0.01) in anti-SRBC IgM antibody 

concentrations.

The immunotoxicity NOAEL is the highest dose tested of 3000 ppm (230 mg/kg bw/d), based on 

an absence of test substance related immunotoxicity findings at this dose.

This study is fully reliable (acceptable/guideline) and satisfies the guideline requirements 

(OPPTS 870.7800) for an immunotoxicity study in rats.

A.4.9 Special/Other Studies 

90- day oral toxicity with DFA (metabolite)

In a 90-day dietary study (MRID 48844113), BCS-AA56716 (97.1%; batch BCOO5984-5-8) 

was administered to Wistar [Rj:WI (IOPS HAN)] rats (10/sex/dose) at concentrations of 0, 200, 

1000, or 6000 ppm (0/0, 12.7/15.6, 66.2/78.7, or 380/472 mg/kg bw/d, respectively). BCSAA56716 (difluoroacetic acid) is a plant and soil metabolite of BYI02960. 

Parameters evaluated included body weight, body weight gain, food consumption, clinical signs, 

Functional Observational Battery parameters, exploratory locomotor activity, haematology, 

clinical chemistry, urinalysis, ophthalmology, organ weights, gross and microscopic pathology. 

Under the conditions of this study BCS-AA56716 did not produced test substance-related effects 

on survival, clinical signs of toxicity, functional observational battery observations, 

ophthalmological observations, or organ weights.
Page 84 of 116

In males at 1000 ppm, mean body weight by study day 8 was 4% lower than controls, 9% 

(p≤0.01) lower than controls by study day 29, and terminal body weights were 12% (p≤0.01) 

lower than controls at study day 92. Lower mean body weight and decreased body weight gain 

were also noted at 6000 ppm, with a mean body weight 4% lower than controls by study day 29, 

6% lower by study day 57, with no further decreases through to study termination (all values 

were not statistically significant). 

In females at 1000 ppm, mean body weight was 5% lower than controls at study day 57, and 

were 4% lower than controls by study day 92 (no statistical significance observed). Lower mean 

body weights during the treatment period were also observed at 6000 ppm in females, with a 

mean body weight 6% (p<0.05) lower than controls at study day 29, 7% (p≤0.05) lower at study 

day 57 (p≤0.05), and 9% (p≤0.01) lower at study day 92.

Decreased body weight gains in both sexes at 1000 and 6000 ppm was accompanied by 

corresponding decreases in absolute (g/d) food consumption from study day 4 onwards (earliest 

time point examined). 

In hematology observations, a 9% lower hemoglobin, 6% lower mean corpuscular volume, and 

8% lower mean corpuscular hemoglobin were noted in 1000 ppm females relative to controls,. 

These findings all displayed poor dose dependency, with similar decreases reported at 6000 ppm. 

. 

In clinical chemistry observations, Serum glucose concentrations and serum bilirubin were 

decreased across all dose levels compared with controls; however, noting the direction of change 

for the reported effects (decreases, rather than increases), the effects were not considered 

toxicologically adverse. 

A range of urinalysis parameters at ≥ 1000 ppm (including urinary volume, ketone levels and 

urinary pH) were considered to be treatment-related, but unlikely to be toxicologically 

significant given the lack of histopathology and clinical pathology changes. 

Test substance related findings at gross necropsy were confined to black foci in the stomach 

gland of both sexes at 1000 ppm (10/20% incidence for M/F) and 6000 ppm (30%/20% 

incidence for M/F). The finding was associated at the histopathological level with focal glandular 

erosion/necrosis in the stomach, and considered to be toxicologically adverse.

The NOAEL was 200 ppm for both sexes (12.7/15.6 mg/kg bw/d for M/F). The LOAEL was 

1000 ppm (66.2/78.7 mg/kg bw/d for M/F), based on decreased body weight gains in males, 

resulting in 12% lower terminal body weights relative to controls (p<0.01), associated decreases 

in food consumption, black foci in the glandular part of the stomach (10/20% incidence for M/F) 

for both sexes that correlated histopathologically with focal glandular erosion/necrosis, and (in 

females only) statistically significant (p≤0.01) decreases in plasma haemoglobin (-9%), mean 

corpuscular volume (-6%), mean corpuscular haemoglobin (-8%) and hematocrit (-7%).

This study is classified as fully reliable (acceptable/guideline) and satisfies guideline requirements 

for a subchronic oral toxicity in rats [OPPTS 870.3100; OECD 408 (1998)].
Page 85 of 116

A.5 Flupyradifurone: Summary of NOAEL/LOAEL (with BW 3⁄4 scaling for human 

equivalent dose)

With the initial glance, the toxicity data on flupyradifurone appear to indicate that the dog is 

more sensitive than the other testing animals. However, with BW 3⁄4 scaling for human 

equivalent dose calculation, the results reveal that the dog and rat have similar sensitivity to the 

effects of flupyradifurone as indicated in the table below. 

Table A.5: Flupyradifurone Summary of NOAEL/LOAEL (with BW 3⁄4 scaling for human equivalent dose)

NOAEL (mg/kg) LOAEL (mg/kg)

Study

Test Animal Human 

Equivalent Dose

Test Animal Human 

Equivalent Dose

28-day oral –rats (gavage) 75 18 200 48

28-day oral tox.-rats (dietary) 36 385

28-day oral tox.-mice 

(dietary)

166/199 (M/F) 

(HDT

28-day oral tox. dogs (diet)

(2 dogs/sex/dose)

62 40 118 75.52

90-day oral tox.—dogs 12 7.68 33 21.12

90-day oral toxicity –rats 

(diet)

38 9.12 156 37.44

90-day oral toxicity –mouse 

(diet)

81 407

28-day Dermal tox.-rats 500 (HDT)

Chronic oral toxicity study in 

dogs.

(1-year; diet)

7.8 4.00 28 17.92

Combined chronic/ 

carcinogenicity study in rats.

15.8 / 22.5 (M/F) 3.8/5.4 81/ 120 (M/F) 

(No compound related 

↑tumor incidence)

19.44/28.8

Carcinogenicity study in 

mice

43 224 

(No compound related 

↑tumor incidence)

Developmental toxicity -

rabbit. (gavage)

Mat- 40 Mat 80

Dev-40 Dev-80

Developmental toxicity –rat 

(gavage)

Mat- 50

Dev-150

Mat- 150

Dev-150

36

36

2-Generation reproduction 

study in rats

Parental-38.7

(HDT)

Reprod-38.7

Offspring 7.7 Offspring: 

1.85 

Parental 137

Reprod-137

Offspring-38.7 Offspring: 9.29

Acute neurotoxicity in rats. 

(gavage)

35 50

Subchronic neurotoxicity 

study in rats.

34.8 143
Page 86 of 116

Table A.5: Flupyradifurone Summary of NOAEL/LOAEL (with BW 3⁄4 scaling for human equivalent dose)

NOAEL (mg/kg) LOAEL (mg/kg)

Study

Test Animal Human 

Equivalent Dose

Test Animal Human 

Equivalent Dose

Developmental neurotoxicity 

study in rats.

Maternal -102 

(HDT)

Offspring-42

Offspring-102

28-Day Dietary 

Immunotoxicity Study

230 (HDT)

No systemic or 

Immunotoxicity was 

see
Page 87 of 116

Appendix B. Metabolism Summary Table

Table B. Overall Summary of Characterization and Identification of Radioactive Residues in Tomato, 

Potato, Apple, Cotton, and Rice Following Application of [Furanone-4-14C] BYI 02960 and 

[Pyridinylmethyl14C] BYI 02960 at Rates and PHIs Reflective of the Proposed Uses

Compound1 Tomato

(drench)

Potato

(seed treatment)

Apple

(foliar)

Cotton

Lint

(foliar)

Rice

(foliar)

TRRs = 0.130P

/0.096F ppm

TRRs =0.076P

/0.078F ppm

TRRs = 0.545P

/1.286F ppm

TRRs=8.846P/4.99

3F ppm

TRRs=0.620P/0.65

9F

% 

TRR

ppm % 

TRR

ppm % 

TRR

ppm %TRR Ppm %TR

R

ppm

BYI 02960 24/36 0.031/0.0

34

40/40 0.031/0.0

31

86/74 0.467/0.9

46

73/70 6.46/3.51 75/57 0.467/0.3

73

6-CNA 13.2/ 0.017/ 22/ 0.016/ 1.5/ 0.008/ 0.4/ 0.031/ 3.1/ 0.019/

CHMP-diglyc37.1/ 0.048/ 4.4/ 0.003/

CHMP-glyc 5.1/ 0.007/ 3.7/0.0

03

0.9/ 0.005/

CHMP 3.3/ 0.004/ 3.9/ 0.003/ 0.8/ 0.004/

OH-glyc 3.4/5.

5

0.004/0.0

05

6.7/6.6 0.005/0.0

05

1.7/1.

1

0.009/0.0

14

Glucose/

carbohydrat

e

/28 /0.026 /14 /0.182 /3.6 /0.023

Difluoroethy

l-aminofuranone

/10 /0.01 /4.2 /0.003 /0.2 /0.003

Acetic acidglyc0.8/0.

5

0.004/0.0

07

0.6/0.4 0.003/0.0

03

Acetic acid 1.1/0.

7

0.006/0.0

09

7.8/6.1 0.048/0.0

40

AMCPdifluroethan 

amine

4.1/ 0.023

OH 1.0/0.

8

0.005/0.0

1

0.4/ 0.002/

Glyoxylic 

acid

0.2/0.2 0.015/0.0

09

0.4/ 0.003/

OHglyc/acetic 

acid

14.6/13

.9

1.30/0.69

4

Bromo/chlor

o

1.6/1.6 0.140/0.0

78

1.5/1.7 0.009/0.0

11

Total 

identified

86/79 0.111/0.0

75

80/50 0.061/0.0

39

98/91 0.53/1.17 90/86 7.94/4.29 89/68 0.552/0.4

50

Total 

characterize

d

12/4.

3

0.016/0.0

04

9.3/12.

4

0.007/0.0

1

0.5/0.

1

0.002/0.0

02

9.5/11 0.837/0.5

30

7.4/17.

2

0.045/0.1

13

Total 

extractable

98/85 93/67 99/92 99/97 8.77/4.82 96/86 0.597/0.5

64

Unextractabl

e (PES)

1.5/1

5

6.6/33 1.3/8.

1

0.8/3.4 0.073/0.1

70

2.7/12.

8

0.017/0.0

85

[Difluoroace

tic acid]

[872] [0.1751]

1 See Table C.1 for names and structures.

2

[1-ethyl14C] BYI 02960. Conducted only with tomato.-

Appendix C. Physical/Chemical Properties and Metabolites
Page 88 of 116

Table C.1. Physicochemical Properties of the Flupyradifurone (99.4% Purity)

Parameter Value Reference

(MRID/BCS Study)

Molecular weight (g/mole) 288.68 MRID 48843601

M-434475-01-1

Melting point/range (°C) 69.0 MRID 48843630

M-367370-01-2

pH 6.6 at 24o C MRID 488436626

M-412128-01-2

Density (g/cm3) 1.43 g/ml at 20o C MRID 48843642

M-412635-01-2

Water solubility (g/L at 20°C) 3.2 MRID 48843643

M-204285-01-2

Solvent solubility (g/L at 20°C) Methanol

n-Heptane

Toluene

Dichloromethane

Acetone

Ethyl acetate

Dimethyl sulfoxide

>250

0.0005

3.7

>250>25

0

>250

>250

MRID 48843656

M-414064-01-2

Vapor pressure (Pa) 9.1 x 10-7at 20oC

1.7 x 10-7at 25oC

2.6 x 10-7at 50oC

MRID 48843650

M-309853-01-3

Dissociation constant (pKa) No dissociation occurs in aqueous 

solutions in the pH range between 

1 and 12.

MRID 48843636

M-418626-091-2

Octanol/water partition coefficient Log(KOW) 1.2 (pH 4 – 9) MRID 48843639

M-414485-01-2

Table C.2. Tabular Summary of Flupyradifurone and Its Metabolites and Degradates.

Chemical Name (other names in 

parenthesis) and Structure

Matrix Percent TRR (PPM)

Matrices -

Major Residue 

(>10%TRR)

Matrices -

Minor Residue 

(<10%TRR)

Parent

Flupyradifurone

BYI 02960

4-[[(6-chloropyridin-3-yl)methyl]

(2,2-difluoroethyl) amino]furan

-2(5H)-one (IUPAC)

2(5H)-furanone, 4-[[(6-chloro-3-

pyridinyl)methyl](2,2-difluoroethyl)

amino]- (CAS)

CAS-No.: 951659-40-8

Tomato 24P (0.031)

36F (0.034)

Potato 40P (0.031)

40F (0.031)

Apple 86P (0.47)

74F (0. 95)

Cotton 73P (6.5)

70 F (3.5)

Rice grain 75P (0.47)

57F (0.37)

CRC Wheat 

Grain (29 d)

8.3P (0.02)

0.4F (0.004)

CRC Swiss 

Chard (29 d)

46P (0.69)

43 F (0.37)
Page 89 of 116

CRC Turnip 

Leaf (29 d)

62P (0.51)

64 F (0.44)

CRC Turnip 

Root (29 d)

58P (0.04)

56F (0.04) 

Ruminant milk 89P (0.16)

24F (0.25)

Ruminant 

muscle

98P(0.35)

88F (0.48)

Ruminant fat 99P (0.10)

80F (0.21)

Ruminant 

kidney

35P (0.65)

50F (0.74)

Ruminant liver 85 P (1.0)

60F (1.0)

Poultry egg 20P (0.017)

2.3F (0.013)

Poultry muscle 14F (0.005) 9.8P (0.007)

Poultry fat 15P (0.003)

Poultry liver 0.9P (0.004)

0.5F (0.01)

Rat Excreta 40-77 TDA

BYI 02960 Chloro

(Co-elutes with Bromo)

3-chloro-4-{[(6-chloropyridin-3-yl)

methyl](2,2-difluoroethyl)amino}

furan-2(5H)-one

Cotton 1.6P (0.14)

1.6F (0.078)

Rice 0.4P (0.003)

CRC Turnip 

root (29-296 d)

1.4-2.5P (0.001)

1.3-2.5F (0.06-

0.001)

CRC Swiss 

chard (29-296 

d)

0.4P (0.04)

0.4-0.6F (0.003-

0.001

CRC Turnip 

leaves (29-296 

)

1.3-1.6P (0.001-

0.004)

1.1-1.8F (0.007-

0.002)

Water

BYI 02960 bromo

(co-elutes with chloro)

3-bromo-4-{[(6-chloropyridin-3-yl)

methyl](2,2-difluoroethyl)amino}

furan-2(5H)-one

O

Cl N

N

F

F

O

O

Cl N

N

F

F

O

Cl

O

Cl N

N

F

F

O

Br
Page 90 of 116

BYI 02960 OH

4-{[(6-chloropyridin-3-yl)methyl]

(2,2-difluoroethyl)amino}

-5-hydroxyfuran-2(5H)-one

Apple 1.0P (0.005)

0.8F (0.01)

Rice 0.4P (0.002)

CFC Wheat 

grain (29d)

10P (0.018) 2.3F (0.011)

CFC Swiss 

chard (29d)

1.6 P(0.023)

1.9F (0.02)

CFC Turnip 

root (29d)

0.5P (0.001)

0.4F (0.001)

CFC Turnip 

top(29d)

1.4P (0.011)

1.7F (0.012)

Ruminant liver 16P (0.30)

15F (0.22)

Ruminant 

muscle

1.8F (0.01)

Ruminant 

kidney

2.9F (0.008)

Poultry eggs 18P (0.015) 2.3F (0.013)

Poultry muscle 8.1P (0.006)

2.4F (0.004)

Poultry fat 5.5P (0.001)

Poultry liver 1.5 (0.007)

0.8F (0.018)

Rat excreta 13-29 TDA

BYI 02960 OH glyc

3-{[(6-chloropyridin-3-yl)methyl]

(2,2-difluoroethyl)amino}-

5-oxo-2,5-dihydrofuran-2-yl betaD-glucopyranoside

Tomato 3.4P (0.004)

5.5F (0.005)

Potato 6.7P (0.005)

6.6F (0.005)

Apple 1.7P (0.0090

1.1F (0.014)

CFC Wheat 

grain (29-296d)

5.0P (0.009)

2.1F (0.002)

CFC Swiss 

chard (29-

296d)

11-28P (0.16-0.036)

13-21F (0.12-0.033)

CFC Turnip 

leaf (29-296d)

10-12F (0.02-0.09) 9.4-11P (0.02-0.08)

CFC Turnip 

root (29-296d)

2.5-3.8P (0.001-

0.002)

2.1-3.1F (0.001)

BYI 02960-OH-glyc-SA (isomer 1)

And

BYI 02960-OH-glyc-SA (isomer 2)

CRC Swiss 

chard (29-

296d)

1.7-9.2P (0.02-0.04)

4.8-6.7F (0.01-0.05)

CRC Turnip 

leaf (29d)

2.3P (0.02)

O

Cl N

N

F

F

O

OH

O

OH

OH

OH

O

O

Cl N

N

F

F

O

OH
Page 91 of 116

BYI 02960 acetic acid

N-[(6-chloropyridin-3-yl)methyl]-N-(2,2-

difluoroethyl)glycine

Apple 1.1P (0.006)

0.7F ((0.009)

Rice 7.8P (0.048)

6.1F (0.040)

CRC Wheat 

grain (29-296d)

1.8P (0.002)

1.0F (0.002)

CRC Swiss 

chard (29-

296d)

0.6-0.9F (0.001-

0.005)

CRC Turnip 

leaf (29-296d)

1.1-1.3F (0.001-

0.008)

CRC Turnip 

root (29-296d)

0.2-0.3F (0.001)

Rat

Water

BYI 02960-acetic acid-glyc Apple 0.8P (0.004)

0.5F (0.007)

Rice 0.6P (0.003)

0.4F (0.003)

CRC Swiss 

chard (29-

296d)

3.0P (0.013)

0.2-1.6F (0.001-

0.01)

CRC Turnip 

leaf (29d)

0.4P (0.003)

0.5-3.5F (0.001-

0.02)

O

Cl N

N

F

F

O

+ O

glycosylsulfate

Cl N

N

F

F

COOH

Cl N

N

F

F

COOH

glycoside
Page 92 of 116

BYI 02960 glyoxylic acid

N-(6-chloropyridin-3-ylmethyl)-N-(2,2-

difluoroethyl)oxamic acid

Cotton 0.2P (0.015)

0.2F (0.009)

Rice 0.4P (0.002)

CRC Wheat 

grain (29d)

(15% wheat 

straw, forage, 

hay)

6.0P (0.011)

CRC Swiss 

chard (29d)

2.6P (0.039)

4.7F (0.041)

CRC Turnip 

leaf (29d)

2.6P (0.021)

6.6F (0.045)

CRC Turnip 

root (29d)

12F (0.009) 8.6P (0.006)

BYI 02960 CHMP

6-chloropyridin-3-ylmethanol (IUPAC)

3-pyridinemethanol, 6-chloro- (CAS)

CAS-No.: 21543-49-7

Tomato 3.3P (0.004)

Potato 3.9P (0.003)

Apple 0.8P (0.004)

CRC Turnip 

root (29d)

4.1P (0.003)

BYI 02960 CHMP glyc Tomato 5.1P (0.007)

)

Potato 3.7P,(0.003)

Apple 0.9P (0.005)

CRC Swiss 

chard (29d)

5.4P (0.080)

CRC Turnip 

leaf (29-296d)

4.5-5.9P (0.01-0.04)

Cl N

N

F

F

O

COOH

Cl N

OH
Page 93 of 116

CRC Turnip 

root (135d)

2.0P (0.001)

BYI CHMP di-glyc Tomato 37P (0.048)

Potato 4.4P (0.003)

BYI 02960 CHMP glyc di-SA

And

BYI 02960 CHMP glyc tri-SA

Or trisulfate

CRC Swiss 

chard (29-

296d)

3.2-5.3P (0.02-0.08)

6-CNA4

6-chloronicotinic acid (IUPAC)

CAS-No.: 5326-23-8

Tomato2 13.2P (0.017)

Potato3 22P (0.016)

Apple 1.5P (0.008)

Cotton 0.4P (0.031)

Rice 3.1P (0.019)

CRC Wheat 

grain

3.8P (0.007)

CRC Swiss 

chard

7.0P (0.10)

CRC Turnip 

leaf

1.0P (0.008)

CRC Turnip 

root

8.5P (0.006)

Poultry eggs 7.2P (0.006)

Poultry muscle 8.8P (0.;006)

Poultry fat 1.8P (<0.001)

Poultry liver 6.4P (0.028)

Rat excreta 0.4-6.3 TDA

Potato 2.3P (0.003)

Cl N

OH

glycoside Cl N

OH

diglycoside Cl N

OH

glycosyldisulfate Cl N

OH

O
Page 94 of 116

BYI 02960-6-CNA-glycerol-gluA 

(isomers 1, 2 & 3)

CRC Wheat 

grain

(14-29% wheat 

forage, straw, 

hay)

22P (0.16)

BYI 02960-difluoroethyl-amino-furanone 

(DFEAF)

4-[(2,2-difluoroethyl)amino]furan-2(5H)-one

Tomato 10F (0.01)

Potato 4.2F (0.003)

Apple 0.2F (0.003)

CRC Swiss 

chard (29d)

17F (0.14)

CRC Turnip 

leaf

1.0F (0.007)

Rat excreta 0.96-3.5

BYI 02960-difluoroethyl-amino-furanoneOH-glyc

CRC Swiss 

chard (29d)

1.2F (0.01)

BYI 02960-AMCP-difluoroethanamine

N-[(6-chloropyridin-3-yl)methyl]-2,2-

difluoroethanamine

Apple 4.1P (0.023)

Ruminant liver 1.2P (0.02)

Ruminant 

kidney

1.1P (0.02)

Cl N

OH

O

+ glycerol

glucuronide

O

HN

F

F

O

O

HN

F

F

O

+ O

glycoside

Cl N

NH

F

F
Page 95 of 116

BYI 02960-N-formyl-AMCPdifluoroethanamine

N-[(6-chloropyridin-3-yl)methyl]-N-(2,2-

difluoroethyl)formamide

And/Or

BYI 02960-N-acetyl-AMCPdifluoroethanamine

N-[(6-chloropyridin-3-yl)methyl]-N-(2,2-

difluoroethyl)acetamide

CRC Swiss 

chard

2.9P (0.043)

CRC Turnip 

leaf

3.6P (0.030)

CRC Turnip 

root

3.5P (0.003)

BYI 02960-mercapto-lactic acid

3-({4-[(2,2-difluoroethyl)amino]-2-oxo-2,5-

dihydrofuran-3-yl}sulfanyl)-2-

hydroxypropanoic acid

CRC Wheat 

forage, hay , 

straw (NOT 

grain)

1-10F (0.003-0.07)

BYI 02960-amino-furanone

4-aminofuran-2(5H)-one

CRC Wheat 

grain

0.5F (0.002)

CRC Swiss 

chard

3.1F (0.02)

Cl N

N

F

F

CH3

O

O

HN

F

F

O

HO S

O

OH

Cl N

N

F

F

O

H
Page 96 of 116

CRC Turnip 

leaf

0.9F (0.006)

CRC Turnip 

root

4.1 ,(0.003)

BYI 02960-bromo-amino-furanone

4-amino-3-bromofuran-2(5H)-one

CRC Wheat 

Forage, Straw, 

Hay (NOT 

grain)

2-10F (0.01-0.22)

DFA

difluoroacetic acid (IUPAC)

Acetic acid, 2,2-difluoro- (CAS)

CAS-No.: 381-73-7

Tomato 87 (0.18)

Rice*

Potato*

Cotton*

Apple*

CRC Wheat*

CRC Turnip*

CRC Swiss 

chard*

Ruminant*

Poultry*

*Shown to be present in significant amounts by analysis for 

non-labeled compound in the metabolism studies and by 

analyses of crop field trial studies commodity samples and 

livestock feeding studies commodity samples.

Rat excreta 5.3 urine TDA

0.49 feces TDA

Glucose (hexose) Tomato 28F (0.026)

Apple 14F (0.18)

Rice 3.6F (0.023)

CRC Wheat 

grain

71F (0.34)

CRC Turnip 

root

3.4F (0.003)

ANIMAL METABOLITES ONLY

Lactose Ruminant milk 67F (0.70)

O

H2N

O

O

H2N

O

Br

F

F

O

HO

O

HO

CH2OH

OH

OH

OH
Page 97 of 116

BYI 02960-acetyl-AMCP Poultry eggs 23P (0.019)

Poultry muscle 40P (0.028)

Poultry fat 28P (0.006)

Poultry liver 6.3P (0.027)

BYI 02960-AMCP-difluoroethanamine-SA Poultry liver 0.3P (0.001)

BYI 02960-acetyl-cysteinyl-nicotinic acid Poultry liver 0.3P (0.001)

BYI 02960-cysteinyl-nicotinic acid

6-[(2-amino-2-carboxyethyl)sulfanyl]nicotinic 

acid

Ruminant liver 4.8P (0.058)

Ruminant 

kidney

6.1P (0.11)

O

O

CH2OH

OH

OH

OH

O

CH2OH

OH

OH

OH

Cl N

N

H

O

CH3

Cl N

NH

F

F

+ SO3

HO S N

O

HN

OH

O

CH3

O
Page 98 of 116

BYI 02960-hippuric acid

N-[(6-chloropyridin-3-yl)carbonyl]glycine

Ruminant milk 9.1P (0.017)

Ruminant 

muscle

1.3P (0.005)

Ruminant 

kidney

9.5P (0.18)

Ruminant liver 0.8 (0.01)

Rat excreta 1.1 – 10.5 TDA

BYI 02960-CHMP-serinate Poultry excreta - -

BYI 02960-des-difluoroethyl-OH-SA Poultry muscle 2.1P (0.001)

0.5F (0.001)

Poultry fat 5.6P (0.001)

Poultry liver 3.1P (0.014)

0.2F (0.004)

Poultry eggs 0.1F (0.001)

BYI 02960-des-difluoroethyl

4-[(6-chloropyridin-3-ylmethyl)amino]furan2(5H)-one

Poultry eggs 8.9P (0.007)

1.2F (0.006)

Poultry muscle 9.9P (0.007)

2.6F (0.005)

Poultry fat 5.0P (0.001)

Poultry liver 1.8P (0.008)

0.8F (0.017)

Ruminant 

kidney

1.3F (0.019)

HO S N

O

NH2

OH

O

Cl N

N

H

COOH

O

Cl N

O

O

NH2

OH

O

Cl N

N

H

O

+ O

+ SO3

O

Cl N

N

H

O
Page 99 of 116

Rat excreta 1.7- 3.4 TDA

BYI 02960-methylthio-glyoxylic acid

({[6-(methylsulfanyl)pyridin-3-

yl]methyl}amino)(oxo)acetic acid

Ruminant milk 1.5P (0.003)

Ruminant 

muscle

1.3P (0.005)

BYI 02960-OH-SA

3-{[(6-chloropyridin-3-yl)methyl](2,2-

difluoroethyl)amino}-5-oxo-2,5-dihydrofuran2-yl hydrogen sulfate

Poultry eggs 5.1P (0.004)

0.6F (0.003)

Poultry muscle 1.8P (0.00)

Poultry fat 16P (0.003)

Poultry liver 22P (0.098) 5.1F (0.11)

Rat excreta 0.2 – 0.5 TDA

BYI 02960-OH-gluA (isomer 4) Ruminant 

kidney

7.5P (0.14)

3.5F (0.052)

BYI 02960-OH-gluA (isomer 3); (isomer2)

3-{[(6-chloropyridin-3-yl) methyl](2,2-

difluoroethyl) amino}-5-oxo-2,5-dihydrofuran2-yl beta-D-glucopyranosiduronic acid

Ruminant 

kidney

18P (0.33) 6.9F (0.10)

Ruminant liver 1.4P (0.016)

Rat excreta 0.4 – 2.4 TDA

BYI 02960-OH-gluA (isomer 1) Ruminant 

kidney

6.0P (0.11)

2.2F (0.03)

Rat excreta 0.5 – 1.8 TDA

S N

H3C

N

H

O

COOH

O

Cl N

N

F

F

O

O S

O

O

OH

O

Cl N

N

F

F

O

+ O

glucuronide

O

Cl N

N

F

F

O

O gluA
Page 100 of 116

Environment Metabolites Only

BYI 02960-azabicyclosuccinamide (M47)

4-{(2,2-difluoroethyl)[(3-oxo-2-

azabicyclo[2.2.0]hex-5-en-6-

yl)methyl]amino}-4-oxobutanoic acid 

water – aquatic 

photolysis (major)

BYI 02960-succinamide (M48)

4-{[(6-chloropyridin-3-yl)methyl](2,2-

difluoroethyl)amino}-4-oxobutanoic acid 

water – aquatic 

photolysis (major)

O

Cl N

N

F

F

O

+ O

glucuronide

N

H

H

H

O

H

N

F F

O

CO2H

N

N

Cl

F

F

O

CO2H
Page 101 of 116

BYI 02960-deschlorohydroxysuccinamide

(M49)

4-{(2,2-difluoroethyl)[(6-hydroxypyridin-3-

yl)methyl]amino}-4-oxobutanoic acid 

water – aquatic 

photolysis (minor)

Tomato: 0.535 lb ai/acre soil drench, 1.5X, at first bud, 69 - 73 day PHI.

Potato: 0.25 lb ai/acre seed piece treatment. No label except soybean seed treatment.

Apple: 0.155 lb ai/acre foliar, 0.42 X, 14 day PHI

Cotton: 0.344 lb ai/acre foliar, 0.94X, 90% bolls open

Paddy Rice 1: 0.38 lb ai/acre as GR to soil at transplant

Paddy Rice 2: 0.37 lb ai/acre foliar to rice plants, 30 day PHI. No label, but 1X numerous other crop foliar uses.

Hen: 1.0 mg ai/kg bw X 14 days, or 16 -17 mg ai/kg feed/day

Goat: 1.0 mg ai/kg bw X 5 days, or 24 mg ai/kg feed/day

Rat: 2 mg/kg bw and 200 mg/kg bw.

Confined Rotational: 0.387 lb ai/acre to soil (1.1X)

HO N

N

F

F

O

O

O

H
Page 102 of 116

Appendix D. 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 data, which include Pesticide 

Handlers Exposure Database Version 1.1 (PHED 1.1); the Agricultural Handler Exposure Task 

Force (AHETF) database; and ExpoSAC Policy 14 and 15.1 (SOPs for Seed Treatment), are (1) 

subject to ethics review pursuant to 40 CFR 26, (2) have received that review, and (3) are 

compliant with applicable ethics requirements. For certain studies, the ethics review may have 

included review by the Human Studies Review Board. Descriptions of data sources, as well as 

guidance on their use, can be found at the Agency website6.

 

6 http://www.epa.gov/pesticides/science/handler-exposure-data.html and 

http://www.epa.gov/pesticides/science/post-app-exposure-data.html
Page 103 of 116

Appendix E. Qualitative Evaluation of DFA 

Studies submitted in support of the registration of flupyradifurone indicate that there could be 

significant exposure to difluoroacetic acid (DFA) in drinking water and in food (plants and 

animals); DFA was shown to be a mammalian metabolite with approximately 6% of 

flupyradifurone administered to rats being converted to DFA. 

Hazard Considerations

The most sensitive flupyradifurone effects seen in the database were skeletal muscle myofiber 

atrophy/degeneration, decreases in body weight, and decreases in body weight gain at the 

LOAEL of 33 mg/kg/day in the 90-day dog oral toxicity study (NOAEL = 12 mg/kg/day). 

However, these effects would not be expected from DFA, which has a very different chemical 

structure. DFA is also much more polar than the parent compound, which may indicate it can be 

excreted more rapidly. 

The Registrant submitted a genotoxicity study, a range-finding rat toxicity (14-day) study, and a 

sub-chronic rat (90-day) toxicity study with DFA. DFA produced black foci in the glandular part 

of the stomach with correlated histopathology findings of focal glandular erosion/necrosis at 

66.2/78.8 mg/kg/day (M/F). These dose levels and effects confirm that DFA and flupyradifurone 

produce different effects on target different tissues. Although these effects occurred at similar 

potencies (similar comparable NOAELs and LOAELs on a molar basis7), the effects are 

different. Therefore, the toxicity to DFA should be evaluated separately from flupyradifurone. 

DFA was found in tissues (up to 50%) when flupyradifurone was administered to rats in the 

subchronic toxicity studies, so the toxicity of DFA has already been considered somewhat in the 

flupyradifurone toxicity studies and risk assessment. A qualitative Structure-Activity 

Relationship Analysis using DEREK Nexus 2.0 did not identify any toxicity endpoints of 

concern and the structure of DFA does not cause any specific toxicity concerns. One study in the 

literature identified kidney toxicity when administered intra-peritoneally at doses approximately 

10X the NOAEL. However, kidney toxicity was not observed in the sub-chronic rat (dietary) 

toxicity study at doses up to 380 mg/kg/day. 

Therefore, although flupyradifurone and DFA produce toxicity at similar dose levels, the effects 

are not the same, so parent and metabolite cannot be evaluated together. There are no additional 

toxicity concerns based on DFA’s chemical structure or based on any additional literature 

studies. 

Exposure Considerations

Exposure to DFA as a result of flupyradifurone application is expected in food (plant- and 

animal- based) and drinking water. DFA was not a major metabolite in most plant commodities, 

 

7

 Calculation of Equivalent Dose Between DFA and the Parent Compound: MW flupyradifurone = 289 g/mol 

MW DFA = 97 g/mol. 289 g/mol ÷ 97 g/mol = ~ 3 g/mol. NOAEL in 90 day rat oral toxicity study with 

flupyradifurone = 30/38 (M/F) mg/kg/day. NOAEL in 14 day rat oral toxicity study with DFA = 12.7/15.6 (M/F) 

mg/kg/day. 30 mg/kg/day ÷ 3 = ~10 mg/kg/day (which is similar on a molar basis to the DFA NOAEL of 12.7 

mg/kg/day.
Page 104 of 116

but was very significant for the following uses: seed treatment (soybean), soil drench (tomato), 

and foliar (succulent legume vegetables, especially green beans and lima beans, and cucurbits). 

DFA was a major degradate on a relative basis in poultry commodities; but on an absolute basis, 

only very small concentrations of DFA and parent are anticipated at the calculated livestock 

feeding (exposure) levels. DFA is a major environmental degradate depending upon the soil 

type and environmental conditions. DFA is expected to be more mobile than the parent 

compound. Therefore, exposure to DFA is still expected to be relatively low compared to 

exposure to parent flupyradifurone. 

The Agency conducted an exposure assessment using conservative drinking water estimates (see 

table below) and residue data from crop field trials. (The inputs are presented at the end of this 

appendix.) When conducting a screening evaluation of DFA, exposure to DFA is 7X less than 

estimated exposure to flupyradifurone for the general US population, and 5X less than estimated 

exposure to flupyradifurone for children 1-2 years old, the highest exposed population subgroup. 

Table E. Tier I EDWCs for residues of Difluoroacetic acid (DFA).1

Source of Drinking Water (Model)

DFA concentration in drinking water (μg/L)

Acute Annual Average or Post 

Breakthrough Average

Surface Water (Modified Tier 1 Rice Model) 43 43

Surface water (PRZM/EXAMS)

7.35 ( 1 season)

8.18 (2 seasons)

9.71 (3 seasons)

4.34 ( 1 season)

5.12 (2 seasons)

7.74 (3 seasons)

Groundwater (PRZM-GW)

51.7 (1 season)

105 (2 seasons)

152 (3 seasons)

36.0 (1 season)

76.2 (2 seasons)

114 (3 seasons)

1 Refinements can be made to get lower EDWCs. Tier II modeling could be conducted to determine EDWC in groundwater. 

Exposure Considerations

While DFA produces toxicity at a similar potency to the parent compound (similar NOAELs and 

LOAELs on a molar basis), DFA has already been evaluated somewhat in available subchronic 

toxicity studies; is polar and likely to be excreted more rapidly than the parent compound in 

mammals; and its chemical structure does not trigger any specific toxicity concerns. 

Additionally, a screening evaluation of exposure to DFA showed at least 5X less exposure to 

DFA than to flupyradifurone using conservative screening evaluation inputs (noted below). 

Since there is similar potency (albeit with different toxic effects) between flupyradifurone and 

DFA, and a highly conservative assessment indicates exposure to DFA is at least five times less 

than the parent compound, the Agency has no additional risk concerns about exposure to DFA.

Inputs for the Screening Evaluation of DFA

The chronic dietary exposure analysis of flupyradifurone is conservative, incorporating 

recommended tolerance-level values, conservative processing factors based on empirical data, 

and drinking water estimates that assume 3 growing seasons per year. The assessment also 

assumed that 100% of the proposed crops were treated with flupyradifurone. 
Page 105 of 116

U.S. EPA Ver. 3.16, 03-08-d

DEEM-FCID Chronic analysis for DFA - FLUPYRADIFURONE METABOLITE

 NHANES 2003-2008 2-day

Residue file name: C:\Users\KRURY\Documents\My Work Files\BYI 

02960\Dietary\DFAEstimateMedian of Highest Rep Crops with individual Medians and 10X 

without cranberry.R08

 Adjustment factor #2 NOT used.

Analysis Date 07-15-2014/13:11:53 Residue file dated: 07-15-2014/13:11:29

Reference dose (RfD, Chronic) = .0127 mg/kg bw/day

===============================================================================

 Total exposure by population subgroup

-------------------------------------------------------------------------------

 Total Exposure

 -----------------------------------

 Population mg/kg Percent of 

 Subgroup body wt/day Rfd 

-------------------------------------- ------------- ----------------

Total US Population 0.003989 31.4%

Hispanic 0.004098 32.3%

Non-Hisp-White 0.004037 31.8%

Non-Hisp-Black 0.003395 26.7%

Non-Hisp-Other 0.004485 35.3%

Nursing Infants 0.003389 26.7%

Non-Nursing Infants 0.011014 86.7%

Female 13+ PREG 0.003566 28.1%

Children 1-6 0.008134 64.0%

Children 7-12 0.004445 35.0%

Male 13-19 0.003185 25.1%

Female 13-19/NP 0.003068 24.2%

Male 20+ 0.003411 26.9%

Female 20+/NP 0.003560 28.0%

Seniors 55+ 0.003372 26.6%

All Infants 0.008660 68.2%

Female 13-50 0.003482 27.4%

Children 1-2 0.010061 79.2%

Children 3-5 0.007325 57.7%

Children 6-12 0.004730 37.2%

Youth 13-19 0.003125 24.6%

Adults 20-49 0.003543 27.9%

Adults 50-99 0.003418 26.9%

Female 13-49 0.003484 27.4%

-------------------------------------------------------------------------------
Page 106 of 116

Appendix F. Occupational Exposure Tables

Table F.1. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Baseline Attire. 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Baseline Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Mixer/Loader

Mixing/Loading 

Liquids for Aerial 

Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 220 0.219 0.18 lb ai/A 350 acres 0.0129 930 0.000173 69,000 920

Hops 100 220 0.219 0.14 lb ai/A 350 acres 0.010 1,200 0.000134 90,000 1,200

Field crop, typical9 100 220 0.219 0.18 lb ai/A 350 acres 0.0129 930 0.000173 69,000 920

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 220 0.219 0.18 lb ai/A 1200 acres 0.0441 270 0.000591 20,000 270

Mixing/Loading for 

Airblast Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 220 0.219 0.18 lb ai/A 40 acres 0.00147 8,200 0.0000198 610,000 8,100

Hops 100 220 0.219 0.14 lb ai/A 40 acres 0.00114 11,000 0.0000154 780,000 11,000

Mixing/Loading for 

Chemigation 

Application

Soil Directed: Crop 

Group 10-10 (Citrus), 

Crop Group 11-10 

(Pome Fruit), Crop 

Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 220 0.219 0.365 lb ai/A 350 acres 0.0261 460 0.000350 34,000 450
Page 107 of 116

Table F.1. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Baseline Attire. 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Baseline Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Broadcast: Field crop, 

typical9 100 220 0.219 0.18 lb ai/A 350 acres 0.0129 930 0.000173 69,000 920

Soil Directed: Field 

Crop Typical9 100 220 0.219 0.365 lb ai/A 350 acres 0.0261 460 0.000350 34,000 450

Broadcast: Crop Group 

15 (Cereal Grains), 

Cotton, Crop Group 18 

(Alfalfa & Forage 

Crops), Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 220 0.219 0.18 lb ai/A 350 acres 0.0129 930 0.000173 69,000 920

Mixing/Loading for 

Groundboom 

Application

Broadcast: Field Crop 

Typical9 100 220 0.219 0.18 lb ai/A 80 acres 0.00294 4,100 0.0000394 300,000 4,000

Soil Directed: Field 

Crop Typical9 100 220 0.219 0.365 lb ai/A 80 acres 0.00595 2,000 0.0000799 150,000 2,000

Broadcast: Crop Group 

15 (Cereal Grains), 

Cotton, Crop Group 18 

(Alfalfa & Forage 

Crops), Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 220 0.219 0.18 lb ai/A 200 acres 0.00735 1,600 0.0000985 120,000 1,600

Applicator

Aerial Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 2.08 0.0049 0.18 lb ai/A 350 acres 0.000122 98,000 0.00000386 3,100,000 95,000

Hops 100 2.08 0.0049 0.14 lb ai/A 350 acres 0.0000946 130,000 0.0000030 4,000,000 130,000

Broadcast: Field crop, 

typical9 100 2.08 0.0049 0.18 lb ai/A 350 acres 0.000122 98,000 0.00000386 3,100,000 95,000
Page 108 of 116

Table F.1. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Baseline Attire. 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Baseline Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 2.08 0.0049 0.18 lb ai/A 1200 acres 0.000416 29,000 0.0000133 900,000 28,000

Airblast Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 1,770 4.71 0.18 lb ai/A 40 acres 0.0118 1,000 0.000424 28,000 970

Hops 100 1,770 4.71 0.14 lb ai/A 40 acres 0.00919 1,300 0.00033 36,000 1,300

Groundboom 

Application

Broadcast: Field crop, 

typical9 100 78.6 0.34 0.18 lb ai/A 80 acres 0.00105 11,000 0.0000613 200,000 10,000

Soil Directed: Field 

crop, typical9 100 78.6 0.34 0.365 lb ai/A 80 acres 0.00213 5,600 0.000124 97,000 5,300

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 78.6 0.34 0.18 lb ai/A 200 acres 0.00262 4,600 0.000153 78,000 4,300

Flagger

Flagger for Aerial Hops 100 11 0.35 0.14 lb ai/A 350 acres 0.00050 24,000 0.000215 56,000 17,000
Page 109 of 116

Table F.1. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Baseline Attire. 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Baseline Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Application Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds), 

Field crop, typical9, 

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 11 0.35 0.18 lb ai/A 350 acres 0.00643 19,000 0.000276 43,000 13,000

Mixer/loader/Applicator

Backpack Sprayer

Ground/Soil Directed: 

Crop Group 10-10 

(Citrus)

100 8,260 2.58 0.0365 lb 

ai/gal 40 gallons 0.0112 1,100 0.0000471 250,000 1,100

Mechanically 

Pressurized Handgun

Broadcast: Crop Group 

10-10 (Citrus), Crop 

Group 11-10 (Pome 

Fruit), Crop Group 13-

07B (Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 1,300 3.9 0.0365 lb 

ai/gal 1,000 gallons 0.0441 270 0.00178 6,700 260

Ground/Soil Directed: 

Crop Group 10-10 

(Citrus)

100 1,300 3.9 0.0365 lb 

ai/gal 1,000 gallons 0.0441 270 0.00178 6,700 260

Broadcast: Field crop, 

typical9 100 1,300 3.9 0.0365 lb ai/gal 1,000 gallons 0.0441 270 0.00178 6,700 260

Soil Application: Field 

crop, typical9 100 1,300 3.9 0.0365 lb ai/gal 1,000 gallons 0.0441 270 0.00178 6,700 260

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (May 2013); Level of mitigation: Baseline. *Aerial Application is assessed assuming a closed cockpit 

(engineering controls).

2 Based on proposed label (Reg. No. SivantoTM (EPA Reg. No. 264-RRUR)).

3 Exposure Science Advisory Council Policy #9.1.
Page 110 of 116

4 Dermal Dose = Dermal Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A or gal/day) × DAF (7.42%) ÷ BW 

(80 kg).

5 Dermal MOE = Dermal NOAEL (mg/kg/day) ÷ Dermal Dose (mg/kg/day).

6 Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A or gal/day) ÷ BW (80 kg).

7 Inhalation MOE = Inhalation NOAEL (mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

8 Total MOE = NOAEL (12 mg/kg/day) ÷ (Dermal Dose + Inhalation Dose).

9 Crop Subgroup 1B (except sugarbeet), Crop Group 4 (Leafy Vegetables, except Brassica), Crop Group 5 (Brassica Cole Leafy Vegetables), Foliar Application to Crop Group 8-10 (Fruiting 

Vegetables), Foliar Application Crop Group 9 (Cucurbit Vegetables), Crop Group 13-07B (Bushberries, lowbush), Crop Subgroup 13-07G (Low Growing Berries).

Table F.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Label-Specified PPE (Gloves). 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Gloves Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Mixer/Loader

Mixing/Loading 

Liquids for Aerial 

Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 37.6 0.219 0.18 lb ai/A 350 acres 0.0022 5,500 0.000173 69,000 5,100

Hops 100 37.6 0.219 0.14 lb ai/A 350 acres 0.00177 7,000 0.000134 90,000 6,500

Field crop, typical9 100 37.6 0.219 0.18 lb ai/A 350 acres 0.00220 5,500 0.000173 69,000 5,100

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 37.6 0.219 0.18 lb ai/A 1200 acres 0.00753 1,600 0.000591 20,000 1,500

Mixing/Loading for 

Airblast Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 37.6 0.219 0.18 lb ai/A 40 acres 0.000251 48,000 0.0000198 610,000 44,000

Hops 100 37.6 0.219 0.14 lb ai/A 40 acres 0.000196 61,000 0.0000154 780,000 57,000

Mixing/Loading for 

Chemigation 

Soil Directed: Crop 

Group 10-10 (Citrus), 100 37.6 0.219 0.365 lb ai/A 350 acres 0.00445 2,700 0.000350 34,000 2,500
Page 111 of 116

Table F.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Label-Specified PPE (Gloves). 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Gloves Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Application Crop Group 11-10 

(Pome Fruit), Crop 

Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

Broadcast: Field crop, 

typical9 100 37.6 0.219 0.18 lb ai/A 350 acres 0.00220 5,500 0.000173 69,000 5,100

Soil Directed: Field 

Crop Typical9 100 37.6 0.219 0.365 lb ai/A 350 acres 0.00445 2,700 0.000350 34,000 2,500

Broadcast: Crop Group 

15 (Cereal Grains), 

Cotton, Crop Group 18 

(Alfalfa & Forage 

Crops), Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 37.6 0.219 0.18 lb ai/A 350 acres 0.00220 5,500 0.000173 69,000 5,100

Mixing/Loading for 

Groundboom 

Application

Broadcast: Field Crop 

Typical9 100 37.6 0.219 0.18 lb ai/A 80 acres 0.000502 24,000 0.0000394 300,000 22,000

Soil Directed: Field 

Crop Typical9 100 37.6 0.219 0.365 lb ai/A 80 acres 0.00102 12,000 0.0000799 150,000 11,000

Broadcast: Crop Group 

15 (Cereal Grains), 

Cotton, Crop Group 18 

(Alfalfa & Forage 

Crops), Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 37.6 0.219 0.18 lb ai/A 200 acres 0.00125 9,600 0.0000985 120,000 8,900

Applicator

Aerial Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

100 2.08 0.0049 0.18 lb ai/A 350 acres 0.000122 98,000 0.00000386 3,100,000 95,000
Page 112 of 116

Table F.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Label-Specified PPE (Gloves). 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Gloves Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Except Almonds)

Hops 100 2.08 0.0049 0.14 lb ai/A 350 acres 0.0000946 130,000 0.0000030 4,000,000 130,000

Broadcast: Field crop, 

typical9 100 2.08 0.0049 0.18 lb ai/A 350 acres 0.000122 98,000 0.00000386 3,100,000 95,000

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 2.08 0.0049 0.18 lb ai/A 1200 acres 0.000416 29,000 0.0000133 900,000 28,000

Airblast Application

Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 1,590 4.71 0.18 lb ai/A 40 acres 0.0106 1,100 0.000424 28,000 1,100

Hops 100 1,590 4.71 0.14 lb ai/A 40 acres 0.00825 1,500 0.00033 36,000 1,400

Groundboom 

Application

Broadcast: Field crop, 

typical9 100 16.1 0.34 0.18 lb ai/A 80 acres 0.000215 56,000 0.0000613 200,000 44,000

Soil Directed: Field 

crop, typical9 100 16.1 0.34 0.365 lb ai/A 80 acres 0.000436 28,000 0.000124 97,000 22,000

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 16.1 0.34 0.18 lb ai/A 200 acres 0.000538 22,000 0.000153 78,000 17,000

Flagger

Flagger for Aerial Hops 100 12 0.35 0.14 lb ai/A 350 acres 0.000545 22,000 0.000215 56,000 16,000
Page 113 of 116

Table F.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flupyradifurone with Label-Specified PPE (Gloves). 

Exposure Scenario Crop or Target Level of 

Concern

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure (μg/lb 

ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Gloves Baseline Dose 

(mg/kg/day)4 MOE5 Dose (mg/kg/day)6 MOE7 MOE8

Application Crop Group 10-10 

(Citrus), Crop Group 

11-10 (Pome Fruit), 

Crop Group 13-07B 

(Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds), 

Field crop, typical9, 

Crop Group 15 (Cereal 

Grains), Cotton, Crop 

Group 18 (Alfalfa & 

Forage Crops), 

Peanuts, Crop 

Subgroup 1C, Crop 

Group 6 (Legume 

Vegetables)

100 12 0.35 0.18 lb ai/A 350 acres 0.000701 17,000 0.000276 43,000 12,000

Mixer/loader/Applicator

Backpack Sprayer

Ground/Soil Directed: 

Crop Group 10-10 

(Citrus)

100 8,260 2.58 0.0365 lb 

ai/gal 40 gallons 0.0112 1,100 0.0000471 250,000 1,100

Mechanically 

Pressurized Handgun

Broadcast: Crop Group 

10-10 (Citrus), Crop 

Group 11-10 (Pome 

Fruit), Crop Group 13-

07B (Bushberries, 

Highbush), Crop 

Group 14 (Tree Nuts, 

Except Almonds)

100 1,300 3.9 0.0365 lb 

ai/gal 1,000 gallons 0.0132 910 0.00178 6,700 800

Ground/Soil Directed: 

Crop Group 10-10 

(Citrus)

100 1,300 3.9 0.0365 lb 

ai/gal 1,000 gallons 0.0132 910 0.00178 6,700 800

Broadcast: Field crop, 

typical9 100 1,300 3.9 0.0365 lb ai/gal 1,000 gallons 0.0132 910 0.00178 6,700 800

Soil Application: Field 

crop, typical9 100 1,300 3.9 0.0365 lb ai/gal 1,000 gallons 0.0132 910 0.00178 6,700 800

1 Based on the “Occupational Pesticide 
Page 114 of 116

Handler Unit Exposure Surrogate Reference Table” (May 2013); Level of mitigation: Gloves. *Aerial Application is assessed assuming a closed 

cockpit (engineering controls).

2 Based on proposed label (Reg. No. SivantoTM (EPA Reg. No. 264-RRUR)).

3 Exposure Science Advisory Council Policy #9.1.

4 Dermal Dose = Dermal Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre or gal) × Area Treated or 

Amount Handled (A or gal/day) × DAF (7.42%) ÷ BW (80 kg).

5 Dermal MOE = Dermal NOAEL (mg/kg/day) ÷ Dermal Dose (mg/kg/day).

6 Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre or gal) × Area Treated 

or Amount Handled (A or gal/day) ÷ BW (80 kg).

7 Inhalation MOE = Inhalation NOAEL (mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

8 Total MOE = NOAEL (12 mg/kg/day) ÷ (Dermal Dose + Inhalation Dose).

9 Crop Subgroup 1B (except sugarbeet), Crop Group 4 (Leafy Vegetables, except Brassica), Crop Group 5 (Brassica Cole Leafy Vegetables), 

Foliar Application to Crop Group 8-10 (Fruiting Vegetables), Foliar Application Crop Group 9 (Cucurbit Vegetables), Crop Group 13-07B 

(Bushberries, lowbush), Crop Subgroup 13-07G (Low Growing Berries).
Flupyradifurone Human Health Risk Assessment DP No. D407063

Page 115 of 116

Table F.3. Summary of Short- and Intermediate-Term Handler Exposures and Risks for Flupyradifurone Seed Treatment of Soybean 

Seeds1.

Maximum 

Application Rate2

Dermal

Unit Exposure3

Inhalation

Unit 

Exposure3

Amount of 

Seed 

Treated

or Planted 

Per Day4

Dermal 

Dose5

Inhalation Dose6 Dermal 

MOE7

Inhalation 

MOE8

Combined 

MOE9

lb ai/lb seed mg/lb ai mg/lb ai lb seed/day mg/kg/day mg/kg/day LOC = 

100 LOC = 100 LOC = 100

Loader/Applicator

0.00054 0.023 0.00034 281,250 0.00323 0.00000000032 3,700 38,000,000,000 3,700

Sewer

0.00054 0.0062 0.00023 281,250 0.000873 0.000000000016 14,000 770,000,000,000 14,000

Bagger

0.00054 0.0091 0.00016 281,250 0.00128 0.000000000023 9,400 510,000,000,000 9,400

Multiple Activities

0.00054 0.042 0.0016 281,250 0.00591 0.0000000050 2,000 2,400,000,000 2,000

Planters

0.00054 0.25 0.0034 26,667 0.0033 0.000000035 3,600 340,000,000 3,600

1 Seed treatment rate calculations are based on the following assumptions: Soybean Seeds: 1,500 to 3,600 seeds per lb.

2 Application Rate based on proposed label for flupyradifurone (EPA Reg. No. 264-RRUE).

3 Unit Exposures from HED Exposure Science Advisory Council Policy 14: Standard Operating Procedures for Seed Treatment (baseline 

inhalation = no respirator).

4 HED default for lb seed treated/planted per day from HED Exposure Science Advisory Council Interim Policy 15.1 and the BEAD memo 

“Acres Planted Per Day and Seeding Rates of Crops Grown in the United States” (J. Becker, March 2011).

5 Daily Dermal Dose (mg/kg/day) = daily inhalation unit exposure (mg/lb ai) × application rate (lb ai/lb seed) × amount planted (lb seed/day) × 

dermal absorption factor (7.42%) ÷ body weight (80 kg adult).

6 Daily Inhalation Dose (mg/kg/day) = daily inhalation unit exposure (mg/lb ai) × application rate (lb ai/lb seed) × amount planted (lb seed/day) 

÷ body weight (80 kg adult).

7 Dermal MOE = NOAEL (12 mg/kg/day for short- and intermediate-term exposure) ÷ Dermal Dose (mg/kg/day). Level of concern = 100.

8 Inhalation MOE = NOAEL (12 mg/kg/day for short- and intermediate-term exposure) ÷ Inhalation Dose (mg/kg/day). Short-term level of 

concern = 100.

9 Total MOE = NOAEL (12 mg/kg/day) ÷ (Dermal Dose + Inhalation Dose).
Flupyradifurone Human Health Risk Assessment DP No. D407063

Page 116 of 116

Table F.4. Worst-Case Short- and Intermediate-Term Occupational Post-application Non-Cancer Exposure and Risk 

Estimates for Flupyradifurone.

Crop/Site Activities

Application 

Rate (lb ai/A)

Transfer Coefficient 

(cm2/hr) DFR1 Dermal Dose (mg/kg/day)2 MOE3

Crop Group 1B and 

Crop Group 1C (Beet, 

Potato, Turnip)

Hand Set Irrigation 0.18 1900 0.50 0.0071 1,700

Crop Group 4 (Leafy 

Vegetables Except 

Brassica)

Hand Set Irrigation 0.18 1900 0.50 0.0071 1,700

Crop Group 5 

(Brassica Leafy 

Vegetables)

Scouting, Hand 

Harvesting, Hand 

Weeding

0.18 4200 0.50 0.0157 760

Crop Group 6 (Legume 

Vegetables) Hand Set Irrigation 0.18 1900 0.50 0.0071 1,700

Crop Group 8-10 

(Fruiting Vegetables) Hand Set Irrigation 0.18 1900 0.50 0.0071 1,700

Crop Group 9 

(Cucurbit Vegetables)

Hand Harvesting, 

Mechanically 

Assisted Harvesting, 

Training, Turning,

0.18 550 0.50 0.0021 5,800

Crop Group 10-10 

(Citrus)

Hand Harvesting 0.18 1400 0.50 0.0052 2,300

Crop Group 11-10 

(Pome Fruit) Thinning Fruit 0.18 3600 0.50 0.0135 890

Crop Subgroup 13-07B 

(Bushberries, except 

cranberry)

Hand Harvesting 0.18 1400 0.50 0.0052 2,300

Crop Subgroup 13-07G 

(Low Growing Berries)

Hand Harvesting 0.18 1100 0.50 0.0041 2,900

Crop Subgroup 13-07F 

(Small Fruit Vine 

Climbing, Except 

Fuzzy Kiwifruit)

Girdling/Turning 0.18 19300 0.50 0723 170

Crop Group 14 (Tree 

Nuts, Except Almonds)

Hand Harvesting 

(Net) 0.18 1400 0.50 0.0052 2,300

Crop Group 15 (Cereal 

Grains, Except Rice)

Detasseling/Hand 

Harvesting (Sweet 

Corn Only)

0.18 8800 0.50 0.0330 360

Hand Set Irrigation 0.18 1900 0.50 0.0071 1,700

Crop Group 18 [NonGrass Animal Feeds 

(Forage, Fodder, 

Straw, Hay)]

Hand Set Irrigation 0.18 1900 0.50 0.0071 1,700

Cotton Scouting 0.18 210 0.50 0.00079 15,000

Hop

Harvesting, 

Mechanically 

Assisted

0.14 19300 0.39 0.0562 210

Peanut Hand Set Irrigation 0.18 1900 0.50 0.0071 1,700

1 DFR = Application Rate × F × (1-D)t × 4.54E8 μg/lb × 2.47E-8 acre/cm2; where F = 0.25 and D = 0.10 per day 

2 Daily Dermal Dose = [DFR (μg/cm2) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption (7.42 %)]  BW (kg).

3 MOE = POD (12 mg/kg/day) / Daily Dermal Dose.