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 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND

 POLLUTION PREVENTION

MEMORANDUM

Date: May 15, 2014

SUBJECT: Bifenazate: Occupational and Residential Exposure/Risk Assessment for Proposed 

Uses on Herb Subgroup 19A, Fruiting Vegetable Group 8-10, Pome Fruit Group 

11-10, and Timothy Grass Forage and Timothy Grass Hay.

PC Code: 000586 DP Barcode: D388802

Decision Nos.: 446177 Registration Nos.: 59639-107

Petition No.: 1E7847 Regulatory Action: Section 3

Risk Assessment Type: Single Chemical

Occupational/Residential Assessment

Case No.: NA

TXR No.: NA CAS No.: 149877-41-8

MRID No.: NA 40 CFR: §180.572

FROM: Lata Venkateshwara, Environmental Scientist

Risk Assessment Branch 1

Health Effects Division (7509P)

THROUGH: Kelly M. Lowe, Environmental Scientist

Charles Smith, Branch Chief

Risk Assessment Branch 1

Health Effects Division (7509P)

and

Nancy Tsaur, Chemist, ExpoSAC Designated Reviewer

Shalu Shelat, Industrial Hygienist, ExpoSAC Designated Reviewer

Exposure Science Advisory Committee (ExpoSAC) / HED

TO: Barbara Madden, RM 05

Registration Division (7505P) 

Chemtura Corporation has proposed a Section 3 Registration (PP# 1E7847) for application of 

bifenazate to Herb Subgroup 19A (except chive and chervil), Fruiting Vegetable Group 8-10, 

Pome Fruit Group 11-10, and Timothy Grass Forage and Hay. The Registration Division (RD) 

requested that the Health Effects Division (HED) conduct an exposure and risk assessment for 
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these proposed uses of bifenazate. This memorandum assesses occupational and residential 

exposure and risk from the use of bifenazate on the sites mentioned above.

It is HED policy to use the best available data to assess exposure. Sources of generic data, used 

as surrogate data in the absence of chemical-specific data, include the Pesticide Handlers 

Exposure Database Version 1.1 (PHED 1.1), the Agricultural Handler Exposure Task Force 

(AHETF) database, the Outdoor Residential Exposure Task Force (ORETF) database; the

Residential SOPs (Gardens and Trees), and the Agricultural Reentry Task Force (ARTF). Some 

of these data are proprietary, and subject to the data protection provisions of the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA). 

This memorandum was reviewed by the Exposure Science Advisory Committee (ExpoSAC) on 

August 29, 2013. 
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TABLE OF CONTENTS

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

2.0 Summary of Conclusions and Data Requirements......................................................... 6

2.1 Summary of Risk Estimates............................................................................................. 6

2.2 Data Deficiencies and Requirements ............................................................................... 6

3.0 Hazard Characterization................................................................................................... 6

4.0 Proposed Use Profile.......................................................................................................... 9

5.0 Residential Exposure and Risk Estimates ..................................................................... 10

5.1 Residential Handler Exposure/Risk Estimates.......................................................... 10

5.2 Residential Post-application Exposure/Risk Estimates.................................................. 11

5.3 Residential Risk Estimates for Use in Aggregate Assessments................................ 12

5.4 Spray Drift...................................................................................................................... 13

5.5 Residential Bystander Post-Application Inhalation Exposure ....................................... 13

6.0 Occupational Exposure and Risk Estimates.................................................................. 14

6.1 Occupational Handler Exposure/ Risk Estimates..................................................... 14

Appendix A. Residential Handler and Post-application Algorithms.................................... 22

Appendix B. Summary of Occupational and Residential Non-cancer Algorithms ............. 25

Appendix C. Summaries of Dislodgeable Foliar Residue Studies and Proposed Use in 

Assessment................................................................................................................................... 26
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1.0 Executive Summary

This document presents an occupational and residential exposure/risk assessment for the 

proposed application of bifenazate to herb subgroup 19A (except chive and chervil), fruiting 

vegetable group 8-10, pome fruit group 11-10, and timothy grass forage and hay. 

The proposed uses will not result in residential exposure; however, the currently registered 

gardens and ornamentals use has been reassessed in this document to reflect updates to HED’s 

2012 Residential Standard Operating Procedures (SOPs). The residential exposures have been 

revised since they will impact the aggregate assessment for bifenazate.

Proposed Use Profile:

Bifenazate is a selective miticide which controls the motile stage of mites either by direct contact 

or through contact with foliar residues. The petition submitted by the Registrant includes 

addition of the fruiting vegetable group 8-10, herbs subgroup 19A (except chive and chervil), 

and pome fruit group 11-10 to the Acramite®50WS product label (EPA Reg. # 400-503). This 

product is formulated as a wettable-powder (WP) in water-soluble bags (WSB). Application is 

proposed at a maximum rate of 0.5 lb ai/A via ground and aerial application. The petition also 

included addition of timothy forage and hay to the Acramite® 4SC product label (EPA Reg. # 

400-514). This product is formulated as a suspension concentrate (flowable). Application is 

proposed at a maximum rate of 0.75 lb ai/A via ground and aerial application, and chemigation. 

The proposed pre-harvest intervals (PHIs) range from 0 to 7 days.

Hazard Concerns:

HED identified a short- and intermediate-term dermal toxicological endpoint from a prenatal 

developmental toxicity rat study where the LOAEL is 80 mg/kg/day. An estimated 25% dermal 

absorption factor was used for calculating a dermal dose estimate. The short- and intermediateterm inhalation endpoints were derived from the route specific 28-day inhalation study in rats 

where the NOAEL is 0.030 mg/L. The inhalation study NOAEL was converted to human 

equivalent concentrations (HECs; 0.0009 and 0.0039 mg/L for residential and occupational 

exposures, respectively) and human equivalent doses (HEDs; 0.14 and 0.19 mg/kg/day for 

residential and occupational exposures, respectively). The level of concern for inhalation 

exposure is 30 which includes interspecies (3x), and intraspecies (10x) uncertainty factors. The 

interspecies factor was reduced from 10x to 3x due to the HEC calculation accounting for 

pharmacokinetic (not pharmacodynamic) interspecies differences. The level of concern for 

dermal exposure is 100 which includes interspecies (10x), intraspecies (10x), and FQPA (1x).

The average adult body weight of 80 kg was used for estimating dermal dose and 80 kg was used 

for estimating inhalation dose. No evidence of carcinogenicity was seen in the rat and mouse 

studies and HED classified bifenazate as "not likely" to be a human carcinogen by any relevant 

route of exposure.

Residential Exposure/Risk:

The proposed uses will not result in residential exposure; however, the currently registered 

garden and ornamental use has been reassessed in this document to reflect updates to HED’s 

2012 Residential Standard Operating Procedures (SOPs). A total aggregated risk index (ARI) 

approach was used since the levels of concern (LOCs) for dermal exposure (100) and inhalation 

exposure (30) are different. The dermal and inhalation exposure risk estimates for residential 
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handlers are not of concern at baseline for all scenarios. All the ARIs are above 1 and do not 

exceed HED’s LOC for all scenarios. All adult and children (6 to 11 years) dermal postapplication risk estimates for exposure to treated trees and gardens are not of concern (margins 

of exposure or MOEs) ≥ 100). 

Occupational Handler Exposure:

Occupational handler short- and intermediate-term exposure is anticipated from the proposed 

uses. Chronic exposure is not expected for the proposed uses. Bifenazate is classified as “not 

likely to be carcinogenic to humans;” therefore, a cancer assessment was not conducted. The 

label for Acramite®- 50WS only requires protective eyewear, long-sleeved shirt and long pants; 

shoes and socks. The label does not require gloves. The label for Acramite®- 4SC requires longsleeved shirt and long pants, shoes plus socks. It includes a statement that “When not using a 

closed system, wear apron and chemically resistant gloves made of any waterproof material for 

mixing/loading activities.”

Inhalation risk estimates were not of concern for all scenarios. MOEs ranged from 100 to 12,000 

(MOEs ≥ 30). Dermal risk estimates were not of concern for all scenarios. MOEs ranged from 

110 to 33,000 (MOEs ≥ 100). All ARIs are greater than 1 except for the following scenarios that 

require single layer of gloves:

 Mixing/loading liquids for aerial and chemigation applications and 

 Mixing/loading/application of liquids via mechanically pressurized handgun (foliar). 

Occupational Post-application Exposure:

Post-application dermal exposure will occur since bifenazate is applied post-emergence as a 

foliar spray. Chemical-specific DFR data were available and used for bifenazate. The short- and 

intermediate-term risk estimates are not of concern (i.e., (MOEs≥100)) on the day of treatment 

(i.e., Day 0) for the post-application exposure activities. Based on the Agency's current 

practices, a quantitative occupational post-application inhalation exposure assessment was not 

performed for bifenazate 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 bifenazate.

The 12-hour REI listed on the label is adequate to protect agricultural workers from postapplication exposures to bifenazate.

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; the Outdoor Residential Exposure Task Force (ORETF) database; and 

the Residential SOPs (Gardens/Trees), 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 
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Board. Descriptions of data sources, as well as guidance on their use, can be found at the 

Agency website1. 

2.0 Summary of Conclusions and Data Requirements

2.1 Summary of Risk Estimates

Residential Risk Estimate Summary:

The dermal and inhalation exposure risk estimates for residential handlers are not of concern at 

baseline for all scenarios. All adult and children (6<11 years) dermal post-application risk 

estimates for exposure to treated trees and treated gardens are not of concern (MOEs ≥ 100). 

Occupational Risk Estimate Summary:

Occupational handler inhalation and dermal risk estimates were not of concern for all scenarios. 

The interim Worker Protection Standard (WPS) restricted-entry interval (REI) of 12 hours is 

adequate to protect agricultural workers. 

2.2 Data Deficiencies and Requirements

There are no data deficiencies or data requirements for the proposed new use of bifenazate.

3.0 Hazard Characterization

The acute toxicity data for bifenazate is summarized below in Table 3.1. 

Table 3.1 Acute Toxicity of Bifenazate.

Guideline

No. Study Type MRID # Results Toxicity Category

870.1100 Acute Oral 44464934 LD50 > 5,000 mg/kg IV

870.1200 Acute Dermal 44464936 LD50 > 5000 mg/kg IV

870.1300 Acute Inhalation 44464937 LC50 > 4.4 mg/L IV

870.2400 Primary Eye Irritation 44464938 slight irritation IV

870.2500 Primary Skin Irritation 44464939 slight irritation IV

870.2600 Dermal Sensitization 45385101 dermal sensitizer Magnusson/Kligman

870.2600 Dermal Sensitization 44464940 not a dermal sensitizer Buehler

Toxicological doses selected for use in this assessment are summarized in Tables 3.2 and 3.3. 

The short- and intermediate-term dermal endpoints were derived from the 21-day dermal rat 

study where the NOAEL is 80 mg/kg/day. The LOAEL is 400 mg/kg/day based upon decreased 

body weight in females, decreased food consumption in both sexes, increased urinary ketones, 

increased urinary protein, increased urinary specific gravity, and decreased urinary volume in 

 

1

http://www.epa.gov/pesticides/science/handler-exposure-data.html and 

http://www.epa.gov/pesticides/science/post-app-exposure-data.html
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both sexes, and increased incidences of extramedullary hematopoiesis in the spleen in both 

sexes. The level of concern is 100 based upon a 10x-UF for inter-species extrapolations, and a 

10x-UF for intra-species variations. This study protects for the early resorptions in the 

developmental rat study where the maternal and fetal effects occur at the same dose. This study

is appropriate for the route as well as the durations of exposure, in both residential and 

occupational settings.. 

The short- and intermediate-term inhalation endpoints were derived from the route-specific 28-

day inhalation study in rats where the NOAEL is 0.030 mg/L. The LOAEL is 0.075 mg/L for 

both sexes based on dried red material around the nose in females, lower body weights and 

weight gains, decreased food consumption, decreased heart and thymus weights in females, 

increased incidences of mild brown pigmentation of the spleen, and minimal to mild 

degeneration of the olfactory epithelium within nasal levels III, IV, and V in both sexes. This 

study is appropriate for the route and duration of exposure, and is protective of adults in 

occupational and residential settings.

The methods and dosimetry equations described in EPA’s RfC guidance (1994) are suited for 

calculating HECs based on the inhalation toxicity NOAEL for use in MOE calculations. The 

regional deposited-dose ratio (RDDR), which accounts for the particulate diameter (mass median 

aerodynamic diameter [MMAD] and geometric standard deviation [g] of aerosols), can be used 

to estimate the different dose fractions deposited along the respiratory tract. The RDDR is also 

based on interspecies differences in ventilation and respiratory-tract surface areas. Thus, the 

RDDR can be used to adjust an observed inhalation particulate exposure of an animal to the 

predicted inhalation exposure for a human. For the 4-week inhalation study with bifenazate, an 

RDDR was estimated at 2.8 based on the reported mass medium aerodynamic diameter 

(MMAD) of 2.20 μm and standard deviation (g) of 2.78 and the respiratory-tract surface area of 

the rat relative to the human. Since the rat inhalation study was carried out for 6 hr/day for 5 

days/week, the only exposure adjustment made was in the assumption of 8 hrs/day for human 

occupational exposures. The resulting HECs are 0.0009 mg/L and 0.0039 mg/L for residential 

and occupational exposures, respectively. The resulting HEDs are 0.14 and 0.19 mg/kg/day for 

residential and occupational exposures, respectively. 

The level of concern for inhalation is 30 which includes interspecies (3x) and intraspecies (10x) 

uncertainty factors. The interspecies factor was reduced from 10x to 3x due to the HEC 

calculation accounting for pharmacokinetic (not pharmacodynamic) interspecies differences. 

The level of concern for dermal exposure is 100 which includes interspecies (10x), intraspecies 

(10x), and FQPA (1x).

The average adult body weight of 80 was used for estimating dermal dose and 80 kg was used 

for estimating inhalation dose. No evidence of carcinogenicity was seen in the rat and mouse 

studies and HED classified bifenazate as "not likely" to be a human carcinogen by any relevant 

route of exposure. 
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Table 3.2. Summary of Toxicological Doses and Endpoints for Bifenazate for Use in Dietary and NonOccupational Human-Health Risk Assessments.

Exposure/ 

Scenario POD

Uncertainty/FQPA 

SFs

RfD, PAD, 

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Incidental Oral 

Short Term (1 

- 30 days) and 

Intermediate 

Term

NOAEL = 

0.9 

mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF = 1x

Residential 

LOC for 

MOE = 100

90-Day Subchronic- Dogs

LOAEL = 10.4 mg/kg/day based upon 

changes in hematological parameters in 

both sexes, increased bilirubin in the urine 

in males, increased absolute and relative 

liver weight in females and liver 

histopathological effects in both sexes.

Dermal Shortand 

IntermediateTerm (1-30 

days and 1-6 

months)

LOAEL = 

80 

mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF = 1x

Residential 

LOC for 

MOE = 100

21-Day Dermal Toxicity-Rat

LOAEL = 400 mg/kg/day based on 

decreased body weight in females, 

decreased food consumption in both 

sexes, increased urinary ketones, 

increased urinary protein, increased 

urinary specific gravity, and decreased 

urinary volume in both sexes, and 

increased incidence of extramedullary 

hematopoiesis in the spleen in both sexes.

Inhalation 

Short- and 

IntermediateTerm (1-30 

days, and 1-6 

months)

Rat 

NOAEL = 

0.03 mg/L 

UFA = 3x

UFH = 10x

FQPA SF = 1x

Residential

LOC for 

MOE = 30

28-Day Inhalation Toxicity-Rat

LOAEL = 0.075 mg/L [M/F] on dried red 

material around the nose in females, lower 

body weights and body-weight gains, 

decreased food consumption, decreased 

heart and thymus weights in females, 

increased incidences of mild brown 

pigmentation of the spleen, and minimal 

to mild degeneration of the olfactory 

epithelium within nasal levels III, IV, and 

V.

HEC= 

0.0009 

mg/L

HED = 

0.14 mg/kg 

bw/day

Cancer (oral, 

dermal, 

inhalation)

Bifenazate is classified as "not likely to be a human carcinogen”.

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

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

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

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

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

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

of concern. N/A = not applicable.
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Table 3.3 Summary of Toxicological Doses and Endpoints for Bifenazate for Use in Occupational Human 

Health Risk Assessments

Exposure/ 

Scenario POD Uncertainty Factors

Level of Concern 

for Risk 

Assessment

Study and Toxicological Effects

Dermal Shortand 

IntermediateTerm (1-30 

days and 1-6 

months)

LOAEL = 

80 

mg/kg/day

UFA = 10x

UFH = 10x

Occupational 

LOC for MOE = 

100

21-Day Dermal Toxicity- Rat

LOAEL = 400 mg/kg/day based on 

decreased body weight in females, 

decreased food consumption in both sexes, 

increased urinary ketones, increased 

urinary protein, increased urinary specific 

gravity, and decreased urinary volume in 

both sexes, and increased incidence of 

extramedullary hematopoiesis in the spleen 

in both sexes.

Inhalation 

Short- and 

IntermediateTerm (1-30 

days, and 1-6 

months)

Rat NOAEL

= 0.03 mg/L 

UFA = 3x

UFH = 10x

Occupational

LOC for MOE = 

30

28-Day Inhalation Toxicity-Rat

LOAEL = 0.075 mg/L [M/F] based on 

dried red material around the nose, lower 

body weights and body-weight gains, 

decreased food consumption, mild brown 

pigmentation of the spleen, and minimal to 

mild degeneration of the olfactory 

epithelium within nasal levels III, IV, and 

V in both sexes.

HEC = 

0.0039 

mg/L

HED = 0.19 

mg/kg 

bw/day

Cancer (oral, 

dermal, 

inhalation)

Bifenazate is classified as "not likely” to be a human carcinogen.

POD = a data point or an estimated point that is derived from observed dose-response data and used to mark the 

beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. 

NOAEL = no-observed adverse-effect level. LOAEL = lowest-observed adverse-effect level. UF = uncertainty 

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

members of the human population (intraspecies). MOE = margin of exposure. LOC = level of concern. 

4.0 Proposed Use Profile

Table 4.1 provides a summary of the proposed use patterns. Acramite®50WS is formulated as a 

wettable-powder (WP) in water-soluble bags (WSB). It is proposed for use on fruiting vegetable 

group 8-10, herbs subgroup 19A (except chive and chervil), and pome fruit group 11-10 at a 

maximum application rate of 0.5 lb ai/A via ground and aerial application. Acramite® 4SC is 

formulated as a suspension concentrate (flowable) and is proposed for use on timothy forage and 

hay at a maximum application rate of 0.75 lb ai/A via ground and aerial application, and 

chemigation. 

The proposed pre-harvest intervals (PHIs) range from 0 to 7 days. The Acramite® 4SC label 

requires applicators and other handlers to wear a long-sleeved shirt and long pants and shoes plus 

socks, plus an apron and chemical-resistant gloves of any waterproof material for mixing/loading 

activities (when not using a closed system). The Acramite® 50WS label requires applicators and 

other handlers to wear protective eyewear, long-sleeved shirt and long pants, and shoes plus 

socks. The label does not require gloves.
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Table 4.1. Summary of Proposed Directions for Use of Bifenazate.

Commodity

Trade 

Name 

(EPA 

Reg. No.)

Application 

Timing, Type, 

Equipment

Applicatio

n Rate

(lb ai/A)

Maximum 

Seasonal 

Application 

Rate

(lb ai/A)

PHI

(days)

Maximum 

Number 

Applications

Min. GPA

Herbs 

subgroup 19A 

(except 

chives, 

chervil) Acramite

® 50WS 

(400-503)

Groundboom

Aerial

Airblast

Handheld

0.5 0.5

3

1

50 (ground)

Fruiting 

vegetable 

group 8-10

3

50 (ground);

10 (air)

Pome fruit 

group 11-10 7

50

(ground)

Timothy 

forage and 

hay1

Acramite

® 4SC

(400-514)

Groundboom

Chemigation

Aerial

Handheld

0.75 0.75

0 

(forage) 20

(ground);

7 (hay) 10 (air)

PHI = pre-harvest interval

GPA = gallons of water per acre

1 Application can only be made in Eureka and Humboldt Counties in Nevada

5.0 Residential Exposure and Risk Estimates

The proposed uses do not involve applications by homeowners or commercial applicators in 

residential settings. Therefore, no new residential exposure is expected. However, there are 

existing residential uses that have been reassessed in this document to reflect updates to HED’s 

2012 Residential SOPs (http://www.epa.gov/pesticides/science/residential-exposure-sop.html) 

along with policy changes for body weight assumptions. The revision of residential exposure

estimates will impact the human health aggregate risk assessment for bifenazate.

5.1 Residential Handler Exposure/Risk Estimates

The residential handler exposure assessment estimates dermal and inhalation exposures for 

individuals using bifenazate on residential ornamentals. The quantitative exposure/risk 

assessment developed for residential handlers is based on the following scenarios: 

(1) mixing/loading/applying liquids with manually-pressurized hand wand, 

(2) mixing/loading/applying liquids with hose-end sprayer,

(3) mixing/loading/applying liquids with backpack, and

(4) mixing/loading/applying liquids with sprinkler can.

Unit exposure values and estimates for area treated were taken from HED’s 2012 Residential 

SOPs: Gardens and Trees. 

Combining Exposures/Risk Estimates:
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A total aggregated risk index (ARI) was used since the LOCs for dermal exposure (100) and 

inhalation exposure (30) are different. The target ARI is 1; therefore, ARIs of less than 1 are risk 

estimates of concern. The aggregate risk index (ARI) was calculated as follows.

Aggregate Risk Index (ARI) = 1÷ [(Dermal LOC ÷ Dermal MOE)+ (Inhalation LOC ÷ Inhalation MOE)]

Short-term risk estimates for residential handlers are presented in Table 5.1. Intermediate-term 

exposures are not likely because of the intermittent nature of applications by homeowners. 

Short-term dermal and inhalation risk estimates to residential handlers do not exceed HED’s 

level of concern for all scenarios. All the ARIs are above 1 and do not exceed HED’s level of 

concern for all scenarios.

Table 5.1. Residential Handler Exposure and Risk Estimates for Bifenazate Applications to Ornamentals.

Exposure 

Scenario

Application 

Rate1

Area 

Treated 

Daily2

Baseline Unit 

Exposures (mg/lb ai)

Baseline Dose4

(mg/kg/day) Baseline MOE5 Total

Dermal3Inhalation3 Dermal Inhalation

Dermal

(LOC = 

100)

Inhalatio

n (LOC = 

30)

ARI6

Mixer/Loader/Applicator for Soluble Concentrates( Liquids)

Manuallypressurized 

handwand

0.00125 lb 

ai/gal 5 gal 63 0.018 0.0049 0.0000014 16,000 100,000 150

Hose-end 

sprayer

0.00125 lb 

ai/gal 11 gal 58 0.0014 0.01 0.00000024 8,000 580,000 80

Backpack 0.00125 lb 

ai/gal 5 gal 130 0.14 0.01 0.000011 7,900 13,000 66

Sprinkler 

can

0.00125 lb 

ai/gal 5 gal 58 0.0014 0.0045 0.00000011 18,000 1,300,000 180

1. Application rates based on communication between the Registrant and EPA regarding the maximum rates allowed on the 

labels for the residential use sites. From label 400-508: 2.0 lb ai/gal/128 fl oz gal * 8 fl oz/100 gal = 0.00125 lb ai/gal

2. Based on HED’s SOPs: Gardens and Trees (HED’s 2012 Residential SOPs)

3. Baseline Dermal: Long-sleeve shirt, long pants, shoes and socks and no gloves; Baseline Inhalation: no respirator. 

4. Dose (mg/kg/day) = daily unit exposure (mg/lb ai) x application rate (lb ai/gal) x gal treated x% Absorption (100% dermal and 

100% inhalation assumed) / Body weight (80 kg).

5. MOE = NOAEL (Dermal = 80 mg/kg/day; Inhalation = 0.14 mg/kg/day) / daily dose (mg/kg/day). 

6. ARI = Aggregate Risk Index = 1÷ [(Dermal LOC ÷ Dermal MOE) + (Inhalation LOC÷ Inhalation MOE)].

5.2 Residential Post-application Exposure/Risk Estimates

Non-cancer Exposure/Risk Estimates

Short-term dermal exposure and risk estimates have been assessed for bifenazate. The 

scenarios, routes of exposure and lifestages assessed include:

 Gardens and Trees: adults (dermal) and children 6< 11 years old (dermal).

The lifestages (i.e., adults and children 6 < 11 years old) selected for each post-application 

scenario are based on an analysis provided as an Appendix in the 2012 Residential SOPs. These 

lifestages are not the only lifestages that could be potentially exposed for these post-application 

scenarios; however, the assessment of these lifestages is health protective for the exposures and 

risks for any other potentially exposed lifestages. 

Residential Post-application Exposure Data and Assumptions
Page 12 of 27

A series of assumptions and exposure factors served as the basis for completing the residential 

post-application risk assessment. Each assumption and factor is detailed in the 2012 Residential 

SOPs (http://www.epa.gov/pesticides/science/residential-exposure-sop.html).

Residential Post-application Non-Cancer Exposure and Risk Equations

The algorithms used to estimate residential post-application exposure and dose can be found in 

the 2012 Residential SOPs (http://www.epa.gov/pesticides/science/residential-exposuresop.html). For this assessment a DFR value was used.

Table 5.2 lists the updated assessments of currently registered residential post-application 

exposures and risk estimates. All adult and children dermal post-application risk estimates for 

exposure to treated trees and to treated gardens are not of concern (MOEs ≥ 100.

Table 5.2. Short- and Intermediate-Term Residential Post-application Exposure and Risk 

Estimates for Bifenazate.

Liquid Formulations

Lifestage Post-application Exposure Scenario Dosea MOEsb

(LOC = 100)

Adult

Garden - sprays

0.037 2,200

Child 6 < 11 

years old 0.025 3,100

Adult

Tree – sprays

0.0034 23,000

Child 6 < 11 

years old 0.0023 34,000

a. Dermal Dose (mg/kg/day) = DFRt (μg/cm2) x 0.001 (mg/μg) x short-term TC (cm2/hr) x ET (hr/day) x Dermal Absorption (100%) 

BW (kg) 

b. Dermal MOE = NOAEL (80 mg/kg/day) / Dermal Dose (mg/kg/day)

Inhalation

Based on the Agency's current practices, a quantitative post-application inhalation exposure 

assessment was not performed for bifenazate at this time. However, volatilization of pesticides 

may be a potential source of post-application inhalation exposure to individuals nearby to 

pesticide applications. The Agency sought expert advice and input on issues related to 

volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) 

Scientific Advisory Panel (SAP) in December 2009. The Agency received the SAP’s final report 

on March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The 

Agency is in the process of evaluating the SAP report and may, as appropriate, developing 

policies and procedures, to identifying 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 put into place, the Agency may revisit the need for a quantitative post-application 

inhalation exposure assessment for bifenazate.

5.3 Residential Risk Estimates for Use in Aggregate Assessments 

Table 5.3 reflects the residential risk estimates that are recommended for use in the aggregate 

assessment for bifenazate. 

 The recommended residential exposure for use in the adult aggregate assessment reflects 

dermal post-application exposure to treated gardens.

 The recommended residential exposure for use in the children 6 to 11 years old aggregate 

assessment reflects dermal post-application exposure to treated gardens. 
Page 13 of 27

Table 5.3. Short-Term Residential Exposures for the Bifenazate Combined Residential Risk 

Calculations.

Population

Handler Exposure 

(mg/kg/day)1

Post-application Exposure 

(mg/kg/day)2

Recommended Postapplication Exposure 

for Aggregate 

(mg/kg/day) Dermal Inhalation Dermal Inhalation Oral 3

Adult 0.0045 0.000011 0.037 N/A N/A 0.037

Children 6 < 11 yrs old N/A N/A 0.025 N/A N/A 0.025

1. Handler exposure represents high-end handler exposure, where the appropriate duration is appropriate to assess. 

2. Postapplication exposure represents high-end dermal, inhalation and/or incidental oral exposure for the relevant exposure 

duration.

3. The highest estimated total residential exposure (for adults and child populations) should be used as the basis of the aggregate 

assessments.

5.4 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 bifenazate. 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).

2

 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. 

5.5 Residential Bystander Post-Application Inhalation Exposure

Based on the Agency's current practices, a quantitative post-application inhalation exposure 

assessment was not performed for bifenazate at this time primarily because of the low acute 

inhalation toxicity (Toxicity Category IV), low vapor pressure (<1 x 10-7 mm Hg @ 25°), and the 

low proposed use rate (0.75 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, 2010 

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

process of evaluating the SAP report and may, as appropriate, develop policies and procedures to 

identify the need for and, subsequently, the way to incorporate 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 bifenazate.

 

2 Available: http://www.epa.gov/opp00001/factsheets/spraydrift.htm 
Page 14 of 27

6.0 Occupational Exposure and Risk Estimates

The proposed uses are on agricultural crops; therefore, there is potential for occupational handler 

and post-application exposure. 

6.1 Occupational Handler Exposure/ Risk Estimates

HED uses the term handlers to describe those individuals who are involved in the pesticide 

application process. HED believes that there are distinct job functions or tasks related to 

applications and exposures can vary depending on the specifics of each task. Job requirements 

(amount of chemical used in each application), the kinds of equipment used, the target being 

treated, and the level of protection used by a handler can cause exposure levels to differ in a 

manner specific to each application event. 

Based on the anticipated use patterns, current labeling, and types of equipment that can 

potentially be used, occupational handler exposure is expected from the proposed uses. The 

quantitative exposure/risk assessment developed for occupational handlers is based on the 

following scenarios:

Mixer/Loader:

1.mixing/loading water soluble bags (engineering controls for the wettable powder scenario) 

for aerial application; 

2.mixing/loading water soluble bags (engineering controls for the wettable powder scenario) 

for groundboom application;

3.mixing/loading water soluble bags (engineering controls for the wettable powder scenario) 

for airblast application;

4. open mixing/loading liquids for aerial application;

5. open mixing/loading liquids for groundboom application;

6. open mixing/loading liquids for chemigaton;

Applicator:

7. application of sprays via aerial application;

8. application of sprays via groundboom equipment; 

9. application of sprays via airblast application;

10. application of sprays via chemigation; 

Mixer/Loader/Applicator:

11. application of liquids via mechanically pressurized handgun (foliar);

12. application of wettable powder in water soluble bags via mechanically pressurized 

handgun (foliar); and

Flagger:

13. flagging to support aerial spray applications.

Occupational Handler Exposure Data and Assumptions

A series of assumptions and exposure factors served as the basis for completing the occupational 

handler risk assessments. Each assumption and factor is detailed below on an individual basis.
Page 15 of 27

Application Rate:

Maximum applications rates as provided in Table 4.1 were used in the assessment. 

Unit Exposures:

It is the policy of HED to use the best available data to assess handler exposure. Sources of 

generic handler data, used as surrogate data in the absence of chemical-specific data, include the 

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

Force (AHETF) database, the Outdoor Residential Exposure Task Force (ORETF) database, or 

other registrant-submitted occupational exposure studies. Some of these data are proprietary

(e.g., AHETF data), and subject to the data protection provisions of FIFRA. The standard values 

recommended for use in predicting handler exposure that are used in this assessment, known as 

“unit exposures”, are outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate 

Reference Table3”, which, along with additional information on HED policy on use of surrogate 

data, including descriptions of the various sources, can be found at the Agency website4. 

Area/Amount Treated:

Based on HED ExpoSAC Standard Operating Policy (SOP) No. 9.1, the area treated in a day was 

assumed to be:

 80 acres for groundboom applications,

 350 acres for aerial and chemigation applications,

 40 acres for airblast applications, and

 350 acres for flagging to support aerial treatment. 

Body Weight:

The average adult body weight of 80 kg was used for estimating dermal dose because the 

selected toxicological PODs are based on developmental effects. The average adult body weight 

of 80 kg was used for estimating inhalation dose because the selected toxicological PODs are not 

based on developmental effects. 

Exposure Duration:

HED classifies exposures from 1 to 30 days as short-term and exposures and 30 days to six 

months as intermediate-term. Exposure duration is determined by many things, including the 

exposed population, the use site, the pest pressure triggering the use of the pesticide, and the 

cultural practices surrounding that use site. For most commercial pest control, it is reasonable to 

believe that occupational handlers will not apply the same chemical every day for more than a 

one-month time frame; however, commercial applicators may apply a product over a period of 

weeks. Long-term exposure is not expected.

Note, according to the label there is a maximum of 1 spray per season at a maximum rate of 0.5 

lb ai/ A for herbs subgroup 19A, fruiting vegetable groups 8-10 and pome fruit group 11-10 and 

0.75 lb ai/A for timothy forage and hay. Long-term exposures are not expected; therefore, a 

long-term assessment was not conducted. 

 

3 Available: http://www.epa.gov/opp00001/science/handler-exposure-table.pdf

4 Available: http://www.epa.gov/pesticides/science/handler-exposure-data.html
Page 16 of 27

Mitigation Approaches:

For pesticide handlers, it is HED’s standard practice to present estimates of dermal exposure for 

“baseline” that is, for workers wearing a single layer of work clothing consisting of a long 

sleeved shirt, long pants, shoes plus socks and no protective gloves, as well as for “baseline” and

the use of protective gloves or other Personal Protective Equipment (PPE) as might be necessary. 

The Acramite® 4SC label requires applicators and other handlers to wear a long-sleeved shirt and 

long pants and shoes plus socks, plus an apron and chemical-resistant gloves for mixing/loading 

activities (when not using a closed system). The Acramite® 50WS label requires applicators and 

other handlers to wear protective eyewear, long-sleeved shirt and long pants, and shoes plus 

socks. The label does not require gloves.

Application Rate:

Refer to the proposed use pattern table in Section 4.0.

Occupational Handler Non-Cancer Exposure and Risk Estimate Equations

The algorithms used to estimate non-cancer exposure and dose for occupational handlers can be 

found in Appendix B.

A total aggregated risk index (ARI) was used since the LOC values for dermal exposure (100) 

and inhalation exposure (30) are different. The target ARI is 1; therefore, ARIs of less than 1 are 

risk estimates of concern. The aggregate risk index (ARI) was calculated as follows.

Aggregate Risk Index (ARI) = 1÷ [(Dermal LOC ÷ Dermal MOE)+ (Inhalation LOC ÷ Inhalation MOE)]

Summary of Occupational Handler Non-Cancer Exposure and Risk Estimates

Table 6.1.1 provides a summary of the estimated exposures and risks to occupational pesticide 

handlers. An MOE ≥ 100 is adequate to protect occupational pesticide handlers from dermal 

exposures and an MOE ≥ 30 from inhalation exposures. Inhalation and dermal risk estimates 

were not of concern for all scenarios. All ARIs are greater than 1 and are not risks of concern,

except for the following scenarios that require single layer of gloves:

 Mixing/loading liquids for aerial and chemigation applications and 

 Mixing/loading/application of liquids via mechanically pressurized handgun (foliar). 

Table 6.1.1. Short-/Intermediate-Term Occupational Exposure and Risk Estimates for Bifenazate. 

Exposure 

Scenario

Dermal Unit 

Exposure

(ug/lb ai)1

Inhalation Unit 

Exposure

(ug/lb ai)1

Application 

Rate2

Amount 

Treated 

Daily3

Dose (mg/kg/day)4,5 MOE6,7 Total

Dermal Inhalation

Dermal

(LOC = 

100)

Inhalation

(LOC = 30) ARI9

Mixer/Loader Wettable Powder in Water Soluble Bags

Aerial 

Application

Eng Control8: 

9.8

Eng Control8: 

0.24

0.5 lb ai/A 350 A EC: 0.0215 EC: 0.00053 EC: 3,700 EC: 360 EC: 9.1

Airblast 

Applications 0.5 lb ai/A 40 A EC: 0.00245 EC: 0.00006 EC: 33,000 EC: 3,200 EC: 81

Groundboom 

applications 0.5 lb ai/A 80 A EC: 0.0049 EC: 0.00012 EC: 16,000 EC: 1,600 EC: 40

Mixer/Loader Liquids
Page 17 of 27

Table 6.1.1. Short-/Intermediate-Term Occupational Exposure and Risk Estimates for Bifenazate. 

Exposure 

Scenario

Dermal Unit 

Exposure

(ug/lb ai)1

Inhalation Unit 

Exposure

(ug/lb ai)1

Application 

Rate2

Amount 

Treated 

Daily3

Dose (mg/kg/day)4,5 MOE6,7 Total

Dermal Inhalation

Dermal

(LOC = 

100)

Inhalation

(LOC = 30) ARI9

Aerial 

Application

Base:220 Base: 0.219

0.75 lb ai/A 350 A Base: 0.723

SL/G: 0.123 Base: 0.00072 Base: 110SL/G: 650 Base: 260 Base: 0.98SL/G: 3.7

Chemigation 

Applications 0.75 lb ai/A 350 A Base: 0.723SL/G: 0.123 Base: 0.00072 Base: 110SL/G: 650 Base: 260 Base: 0.98SL/G: 3.7

Groundboom 

applications 0.75 lb ai/A 80 A Base: 0.165 Base: 0.00016 Base: 480 Base: 1,200 Base: 4.3

Applicator

Applicator, Aerial EC: 2.08 EC: 0.0049 0.75 lb ai/A 350 A EC: 0.00683 EC: 0.0000161 EC: 12,000 EC: 12,000 EC: 92

Applicator, Open 

Cab Groundboom Base: 78.6 Base: 0.34 0.75 lb ai/A 80 A Base: 0.00365 Base: 0.443 Base: 180 Base: 750 Base: 1.3

Applicator, Open 

Cab, Airblast Base: 1770 Base: 4.71 0.5 lb ai/A 40 A Base: 0.00383 Base: 0.059 Base: 1,400 Base: 160 Base: 9

Mixer/Loader/Applicator

Mixing/Loading 

Applying Liquids

with Mechanically 

Pressurized 

Handgun (foliar)

Base: 1,300

SLw/G: 390 Base: 3.9 0.0375 lb ai/gallon

1,000 

Gallons Base: 0.61 Base : 0.00183

Base: 130

SLw/G:440 Base: 100 Base: 0.94SLw/G: 1.9

Mixing/Loading 

Applying Water 

Soluble Packets 

with Mechanically 

Pressurized 

Handgun (foliar)

Base: 1,300 Base: 3.9 0.01 lb 

ai/gallon

1,000 

Gallons Base: 0.163 Base:0.000488 Base: 490 Base: 390 Base: 3.6

Flagger

Flagger Base: 

11 Base: 0.35 0.75 lb ai/A 350 A Base: 0.0361 Base: 0.0011 Base: 2,200 Base: 170 Base: 4.5

1 Based on “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (March 2013); includes data from PHED 

/AHETF (level of mitigation: Baseline, PPE, Eng. Controls).: 

Base = single layer and no gloves; no respirator; SL w/G = single layer w/glove; EC = Engineering control; PF5 = dust/mist 

respirator.

2 Based on proposed labels for bifenazate (see Table 4.1).

3 Exposure Science Advisory Council Policy #9.1.

4 Dermal Dose = Dermal Unit Exposure (ug/lb ai) x CF (0.001 mg/ug) x Application Rate (lb ai/acre) x Area Treated (A/day) x% 

Absorption (100% dermal) / Body weight (80 kg).

5 Dermal MOE = Dermal NOAEL (80 mg/kg/day)/Dermal Dose (mg/kg/day).

6 Inhalation Dose = Inhalation Unit Exposure (ug/lb ai) x CF (0.001 mg/ug) x Application Rate (lb ai/acre) x Area Treated 

(A/day) /BW (80 kg). 

7 Inhalation MOE = Inhalation NOAEL (0.19 mg/kg/day)/ Inhalation Dose (mg/kg/day).

8 Engineering controls for the wettable-powder scenario.

9 ARI = Aggregate Risk Index = 1÷ [(Dermal LOC ÷ Dermal MOE) + (Inhalation LOC ÷ Inhalation MOE)].

6.2 Post-application Exposure/ Risk

Dermal

HED expects that post-application dermal exposure will occur since bifenazate is applied postemergence as a foliar spray to upper and lower leaf surfaces. Post-application exposure is 

expected to be short- and intermediate-term based on information provided on proposed labels 

(e.g., according to the label there is a maximum of 1 spray per season at a maximum rate of 0.75 
Page 18 of 27

lb ai/A). Only short-term exposure was assessed, however the assessment is protective of 

intermediate-term exposures since the dermal endpoints are the same. 

Data and Assumptions for Post-application Exposure Scenarios

It is the policy of HED to use the best available data to assess post-application exposure. 

Sources of generic post-application data, used as surrogate data in the absence of chemicalspecific data, are derived from Agricultural Reentry Task Force (ARTF) exposure monitoring 

studies, and, as proprietary data, are subject to the data protection provisions of FIFRA. The 

standard values recommended for use in predicting post-application exposure that are used in 

this assessment, known as “transfer coefficients”, are presented in the “Science Advisory

Council for Exposure (ExpoSAC) Policy 3” 

(http://www.epa.gov/pesticides/science/exposac_policy3.pdf), which, along with additional 

information about the ARTF data, can be found at http://www.epa.gov/pesticides/science/postapp-exposure-data.html. Table 9 provides a summary of the transfer coefficients and activities 

associated with Herb Subgroup 19A (except chive and chervil), Fruiting Vegetable Group 8-10, 

Pome Fruit Group 11-10, and Timothy Grass Forage and Timothy Grass Hay.

Table 6.2.1 summarizes the possible scenarios. In addition, the following assumptions were used 

in the calculations:

• Exposure Duration: 8 hours per day

• Body Weight: 80 kg for dermal and 80 kg for inhalation

•

Table 6.2.1. Anticipated Post-application Activities and Dermal Transfer Coefficients.

Proposed 

Crops

Policy Crop 

Group 

Category

Application Rate

(lb ai/acre)

Transfer Coefficients 

(cm2/hr) Activities

Fruiting 

vegetable 

group 8-10

Vegetable, 

fruiting 0.5

1,900 Irrigation (hand-set)

1,100

Harvesting (hand), 

tying/training

550

Harvesting (hand), 

tying/training

230 Transplanting

210 Scouting

90

Hand pruning, scouting, 

hand weeding, thinning

Herbs 

subgroup 

19A (except 

chives, 

chervil)

Vegetable, 

leafy* 0.5

1,900 Irrigation (hand-set)

1,400 Hand harvesting

230 Transplanting

210 Scouting

70 Hand weeding, thinning
Page 19 of 27

Table 6.2.1. Anticipated Post-application Activities and Dermal Transfer Coefficients.

Proposed 

Crops

Policy Crop 

Group 

Category

Application Rate

(lb ai/acre)

Transfer Coefficients 

(cm2/hr) Activities

Pome fruit 

group 11-10

Tree, “fruit,” 

deciduous 0.5

3,600 Thinning 

1,400 Hand harvesting

580

Scouting, hand pruning, 

training

230 Transplanting

100

Hand weeding, propping, 

orchard maintenance, bird 

control

Timothy 

forage and 

hay 

Field/row crop, 

low/medium 0.75

1,900 Irrigation (hand-set)

1,100 Scouting

210 Scouting

70 Hand weeding, thinning

*Activities and transfer coefficients associated with parsley considered to be representative for new use site. 

Chemical-specific DFR data were available for bifenazate; however, the data were not for the 

currently proposed crops. Since DFR data are not available for the specific crops currently 

proposed for bifenazate, the available data were used as surrogates. Based on a review of the 

available data, it was decided that the DFR data for Spathiphyllum (Peace Lily) in greenhouses 

would be used as a surrogate for the proposed field crops (fruiting vegetable group 8-10, herb 

subgroup 19 A, pome fruit group 11-10, and timothy forage and hay). 

Even though the data are not for the specific crops, it is the only chemical-specific data 

submitted to HED. There are several limitations that were considered such as (1) the study 

represents DFR data collected in a greenhouse which may potentially be a more conservative 

estimate of residue dissipation compared to field crops, (2) the formulation in the study is a 

wettable powder packaged in a water soluble bag whereas one of the proposed labels (EPA 

Reg.#400-514) is for a product that is a suspension concentrate (liquid), (3) the application rate 

was lower in the study (0.29 lb ai/A) compared to the proposed labels (0.5 lb ai/A and 0.75 lb 

ai/A), and (4) the application was made with a calibrated hand-held boom sprayer. 

Tables 6.2.2 provide a summary of the data for use in the post-application exposure and risk 

calculations. Appendix C provides summaries of the studies and references. 

Table 6.2.2. Summary of DFR Values and Regression Analysis Results for Treated Spathiphyllum (Peace Lily) in 

Greenhouses with Bifenazate (MRID# 448597-01).

Input/Parameter Site: Florida

Bifenazate

Application Rate (lb ai/A) aStudy Target Rate = 0.29 lb 

ai/A

0.29 lb ai/A
Page 20 of 27

Table 6.2.2. Summary of DFR Values and Regression Analysis Results for Treated Spathiphyllum (Peace Lily) in 

Greenhouses with Bifenazate (MRID# 448597-01).

Input/Parameter Site: Florida

Spray Volume (GPA) 5 gallons/1000 ft2

Measured Average Day 0 Residue (μg/cm2) 0.151

Predicted Day 0 Residue (μg/cm2) b0.161

Slope -0.07

Half-life (days) 9.9

R

2

0.8433

a. The application was conducted using hand-held boom sprayer. 

b. Regressions are based on data collected after second application. 

The following equations were used to calculate risks for workers performing postapplication 

activities:

Daily Dermal Dose t = (DFRt x CF1 x TC x DA x ET) / BW 

Where:

Daily Dermal Dose = Absorbed dose received from exposure to a pesticide in a given scenario on day 

“t” (mg/kg/day),

DFRt = dislodgeable foliage residue on day "t" (μg/cm2),

CF1 = conversion factor (1E-3 mg/μg),

TC = transfer coefficient (cm2/hr),

DA = dermal absorption factor (unitless),

ET = exposure time (hr/day), and

BW = body weight (kg).

MOE = Point of Departure (mg/kg/day) / Daily Dermal Dose (mg/kg/day)

HED has determined that short- and intermediate-term risk estimates are not of concern (i.e., 

MOEs <100) on the day of treatment (i.e., Day 0) for all the post-application exposure activities. 

Estimates were calculated for the highest transfer coefficients and are protective of all other 

activities. Table 6.2.3 presents the risk estimates for all crops for the highest transfer coefficient 

associated with that crop; this represents the activities with the highest estimated risk. 

Table 6.2.3. Dermal Post-application Exposure and Risk for Bifenazate Using Chemical-Specific DFR Data.

Crop

Application 

Rate

(lb ai/A)

Highest Transfer 

Coefficient for 

Crop (cm2/hr) 

and Associated 

Activity

DFR1

(ug/cm2)

Days After 

Treatment

Daily Dose2

(mg/kg/

day)

MOE3 

Fruiting 

vegetable 

Group 8-10

0.5

1,900

(irrigation; handset)

0.278 0 (12 hours) 0.0528 1,500

Herbs 

Subgroup 

19A

0.5 1,900 (irrigation; 

hand-set) 0.278 0 (12 hours) 0.01528 1,500

Pome fruit 

Group 11-10 0.5 3,600(thinning fruit) 0.278 0 (12 hours) 0.10 800

Timothy 

forage and 

hay

0.75

1,900

(irrigation; handset)

0.416 0 (12 hours) 0.079 1,000
Page 21 of 27

1. Chemical-specific DFR = predicted chrysanthemum DFR data for Spathiphyllum (Peace Lily) in greenhouses for a surrogate for the proposed 

field crops (fruiting vegetable group 8-10, herb subgroup 19 A, pome fruit group 11-10, and timothy forage and hay). Application rate in 

studies is less than the proposed application rate. 

2. Dermal Dose = [DFR (ug/cm2) x TC (cm2/hr) x 0.001 mg/ug x 8 hrs/day x DA (100%)]  body-weight (80 kg).

3 MOE = NOAEL (Short- and Intermediate-term NOAEL 80 mg/kg/day)/Daily Dose (LOC=100)). 

Inhalation 

Based on the Agency's current practices, a quantitative occupational post-application inhalation 

exposure assessment was not performed for bifenazate at this time primarily because it has a low 

acute inhalation toxicity (Toxicity Category IV), has a low vapor pressure (<1 x 10-7 torr at 

25oC), and is applied at a low use rate (max of 0.75 lb ai/A). However, there are multiple 

potential sources of post-application inhalation exposure to individuals performing postapplication activities in previously treated areas. 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, 2010 

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

process of evaluating the SAP report as well as available post-application inhalation exposure 

data generated by the Agricultural Reentry Task Force 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 bifenazate.

REI

Bifenazate is classified in acute Toxicity Category IV for acute dermal, inhalation, and oral 

toxicity, primary eye irritation, and primary skin irritation. Bifenazate is a dermal sensitizer by 

the Magnusson/Kligman method, but not the Buehler method. The 12-hour REI listed on the 

label is adequate to protect agricultural workers from post-application exposures to bifenazate.
Page 22 of 27

Appendix A. Residential Handler and Post-application Algorithms

1.0 Residential Handlers

1.1 Residential Handler Exposure Calculations

1.1.1 Turf, Gardens and Trees, Indoor Environments

Dermal and Inhalation Handler Exposure Algorithm

Daily dermal and inhalation exposure (mg/day) for residential pesticide handlers, for a given 

formulation-application method combination, is estimated by multiplying the formulationapplication method-specific unit exposure by an estimate of the amount of active ingredient 

handled in a day, using the equation below:

E = UE * AR * A

where:

E = exposure (mg/day);

UE = unit exposure (mg/lb ai);

AR = application rate (e.g., lb ai/ft2, lb ai/gal); and

A = area treated or amount handled (e.g., ft2/day, gal/day).

1.2 Residential Handler Dose Calculations

Dermal and/or inhalation absorbed doses normalized to body weight are calculated as:

D = E *AF / BW

where:

D = dose (mg/kg-day);

E = exposure (mg/day);

AF = absorption factor (dermal and/or inhalation); and

BW = body weight (kg).

2.0 Residential Post-application

2.1 Gardens and Trees

Post-application Dermal Exposure Algorithm

Exposure resulting from contacting previously treated gardens and trees while performing 

physical activities is calculated as shown below. Residential post-application exposure 

assessment must include calculation of exposure on the day of application. Therefore, though an 

assessment can present exposures for any day “t” following the application, it must include “day

0” exposure.

E = DFRt * CF1 * TC * ET
Page 23 of 27

where:

E = exposure (mg/day);

DFRt = dislodgeable foliar residue on day "t" (μg/cm2);

CF1 = weight unit conversion factor (0.001 mg/μg);

TC = transfer coefficient (cm2/hr); and

ET = exposure time (hrs/day).

In the absence of chemical-specific data, DFRt can be calculated as follows:

DFRt = AR * FAR * (1-FD)

t

* CF2 * CF3

where:

DFRt = dislodgeable foliar residue on day "t" (μg/cm2);

AR = application rate (lbs ai/ft2or lb ai/acre);

FAR = fraction of ai as dislodgeable residue following application (unitless);

FD = fraction of residue that dissipates daily (unitless);

t = post-application day on which exposure is being assessed;

CF2 = weight unit conversion factor (4.54 x 108μg/lb); and

CF3 = area unit conversion factor (1.08 x 10-3ft2/cm2or 2.47 x 10-8acre/cm2).

Absorbed dermal dose, normalized to body weight, is calculated as:

BW

E AF D*



where:

D = dose (mg/kg-day);

E = exposure (mg/day);

AF = absorption factor (dermal and/or inhalation); and

BW = body weight (kg).

Table A-X: Gardens, Trees, and “Pick-your-own” Farms –Inputs for Residential Postapplication Dermal Exposure 

Algorithm 

Notation

Exposure Factor

(units)

Point 

Estimate(s)

AR Application rate

(mass ai per unit area) [input]

FAR

DFR following application, if chemical-specific is unavailable

(fraction) 0.25

FD

Daily residue dissipation, if chemical-specific is unavailable

(fraction) 0.10

TC

Transfer 

Coefficient

(cm2/hr)

Gardensa Adults 8400

Children 6 < 11 years old 4600

Trees, Retail Adults 1700
Page 24 of 27

Table A-X: Gardens, Trees, and “Pick-your-own” Farms –Inputs for Residential Postapplication Dermal Exposure 

Algorithm 

Notation

Exposure Factor

(units)

Point 

Estimate(s)

Plants (if 

applicable)a Children 6 < 11 years old 930

Indoor Plants Adults 220

Children 6 < 11 years old 120

ET

Exposure 

Time

(hours per 

day)

Home 

activitiesb

Gardens

Adults 2.2

Children 6 < 11 

years old 1.1

Trees, 

Retail 

Plants (if 

applicable)

Adults 1.0

Children 6 < 11 

years old 0.50

Indoor 

Plants

Adults 1.0

Children 6 < 11 

years old 0.50

“Pick-yourown” Farms 

(if applicable)

Adults 5.0

Children 6 < 11 years old 1.9

BW Body weight

(kg)

Adults 80

Children 6 < 11 years old 32

a

Transfer coefficient point estimates from a composite distribution assuming equal proportion 

of time spent conducting various activities. See “Transfer Coefficient” section below. 

Children 6 < 11 years old TC derived using surface area adjustment (see Section 2.3).

b Activity time point estimates from a composite distribution assuming equal proportion of 

each respective activity. Time for children 6 < 11 years old derived using hrs/day ratio 

adjustment. 
Page 25 of 27

Appendix B. Summary of Occupational and Residential Non-cancer Algorithms

Average Daily Dose

Potential daily exposures for occupational handlers are calculated using the following formulas:

E=UE * AR * A * 0.001 mg/ug

where:

E = exposure (mg ai/day),

UE = unit exposure (μg ai/lb ai),

AR = maximum application rate according to proposed label (lb ai A or lb ai/gal), and

A = area treated or amount handled (e.g., A/day, gal/day).

The daily doses are calculated using the following formula:

ADD= 

E * AF

BW

where:

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day),

E = exposure (mg ai/day),

AF = absorption factor (dermal and/or inhalation), and

BW = body weight (kg).

Margin of Exposure

Non-cancer risk estimates for each application handler scenario are calculated using a Margin of 

Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern. The 

daily dermal and inhalation dose received by occupational handlers are compared to the 

appropriate POD (i.e., NOAEL) to assess the risk to occupational handlers for each exposure 

route. All MOE values are calculated using the following formula:

MOE= 

POD

ADD

where:

MOE = margin of exposure: value used by HED to represent risk estimates (unitless),

POD = point of departure (mg/kg/day), and

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day).
Page 26 of 27

Appendix C. Summaries of Dislodgeable Foliar Residue Studies and Proposed Use in 

Assessment

Proposed Uses for Bifenazate

Commodity Foliage Typea Product 

Name

Application 

Equipment

Applicatio

n Rate

(lb ai/A)

Maximum 

Number 

Applications

Per Season

Herbs subgroup 19 A 

(except chives, chervil) Unknown

Florimite® 

50WP 

Groundboom, 

Aerial 

Airblast

Fruiting vegetable group 0.5 1

8-10 smooth

Pome fruit group 11-10 smooth

Timothy forage hay varied Airblast 0.75 1

a. Based on information in the ARTF/ORETF DFR Guidance

DFR Studies Available:

Florimite® 50WP on Spathiphyllum: Dislodgeable Foliar Residue Study (MRID 448597-01).

(HED Review: Memo, L. Venkateshwara, -Nov-2012, D )

This study was designed to collect data to evaluate dislodgeable foliar residue (DFR) 

dissipation for the compound bifenazate from Spathiphyllum (Peace Lily) foliage grown 

in a greenhouse at one site in Florida. One field trial was conducted in two greenhouses, 

one containing treated Spathiphyllum (Peace Lily) plants and the other containing 

untreated plants. Primary review of the study was conducted by Versar Inc., 7 July 2000 

(MRID 448597-01). The secondary review was conducted by HED on November __, 

2012 (D________). 

Florimite® 50WP is a wettable powder packaged in water soluble bags which contains 50

% bifenazate as the active ingredient. Floramite® 50WP was applied with a hand-held 

boom sprayer at 0.29 lb ai/A. Three applications were made with a 30 day application 

interval. DFR samples were collected were up to 28 days after the first two treatments 

and up to 35 days after the last treatment. Samples were analyzed for combined residues 

of bifenazate and a breakdown product UCC-D3598.

Study results indicate that the range of DFR values quantified were quite similar after all 

three applications. The maximum DFR analyzed was 72 μg/sample (after correction for 

68 percent field recovery), found on DAT-1 after the first application. DFR values did 

not decline to <LOQ (i.e. 2 μg/sample) within the 21-day sampling period following the 

first two applications. DFR values did decline to <LOQ by DAT-35 after the third 

application.

Assuming first order kinetics, HED modeled dissipation rates and estimated half lives for 

bifenazate of 9.9 days in Florida (R2= 0.8433). 

Summary of DFR Values and Regression Analysis Results for Treated Spathiphyllum (Peace Lily) in Greenhouses with 

Bifenazate (MRID# 448597-01).
Page 27 of 27

Input/Parameter Site: Florida

Bifenazate

Application Rate (lb ai/A)a

Study Target Rate = 0.29 lb ai/A 0.29 lb ai/A

Spray Volume (GPA) 5 gallons/1000 ft2

Measured Average Day 0 Residue (μg/cm2) 0.151

Predicted Day 0 Residue (μg/cm2) b0.161

Slope -0.07

Half-life (days) 9.9

R

2

0.8433

a. The application was conducted using hand-held boom sprayer .

b. Regressions are based on data collected after second application.

Proposed use of DFR data:

 Use the greenhouse Spathiphyllum (Peace Lily) DFR data to estimate post-application 

exposure for herbs subgroup 19 A (except chives, chervil), fruiting vegetable group 8-10, 

pome fruit group 11-10, Timothy forage hay (use predicted values).

Crop DFR Data Sites

Proposed 

use of DFR 

Data

Characterization

Herbs subgroup 19 A (except 

chives, chervil), Fruiting 

vegetable group 8-10, Pome 

fruit group 11-10, Timothy 

forage hay 

Spathiphyllum

(Peace Lily) 

(Greenhouse)

FL Predicted

DFR values

 DFR data collected in greenhouse; is a 

conservative estimate.

 The formulation in the study is a wettable 

powder packaged in a water soluble bag 

whereas in one of the proposed labels 

(EPA Reg#400-514) the formulation is a 

suspension concentrate (liquid). The 

second label (EPA Reg#400-503) the 

formulation is a wettable powder in a 

water soluble bag.

 The application rate was lower in the 

study (0.29 lb ai/A) compared to the 

proposed label (0.5 lb ai/A and 0.75 lb 

ai/A).

 Application method is not application 

method for proposed crops.