Date: 

Subject: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

June 6, 2015 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

FLUFENACET. Occupational and Residential Exposure Assessment for 

Registration Review. 

PC Code: 12 1903 

Decisio n No.: 485585 

Petition No.: NA 

DP Barcodc: 0427 11 9 

Registra tion No.: NA 

Regulato ry Action: Registration Review 

Risk Assessment Type: Occupational/Residential Exposure Assessment Case No.: 7245 

TXR No.: NA 

MRID No.: NA 

CAS No.: 142459-58-3 

40 CFR: § 180.527 

From: 

Through: 

To: 

Kristin 

Risk Assess

Rury, 

me

Bi

nt 

ol

Branch 

ogist 'f-l1I o~ C~B 3p Health Effects Division (7509P) 

Barry O' Keefe, Senior Biologist JJ. 0 Wo1J,, 

Risk Assessment Branch III (RAB 3) , ~ 

Health Effects Division (7509P) 

and 

Shalu Shelat, Industrial Hygienist -· 

Zaida Figueroa, Industrial Hygienist '?£(., L£. t 

Exposure Science Advisory Committee (ExpoSAC) I HED 

Kristin Rury, Risk Assessor 

Risk Assessment Branch lfI (RAB 3) 

Health Effects Division (7509P) 

And 

Margaret Hathaway 

Chemical Review Manager (CRM) 

Pesticide Re-Evaluation Division (7508P) 

Page I of 33 

-
Introduction 

The Health Effects Division (HED) of the Office of Pesticide Programs (OPP) is charged with 

estimating the risk to human health from exposure to pesticides. As part of Registration Review, 

the Pesticide Re-evaluation Division (PRD) of OPP has requested that HED evaluate the hazard 

and exposure data and conduct occupational and residential exposure assessments, as needed, to 

estimate the risk to human health that will result from the registered uses of flufenacet. This 

memorandum serves as HED's Registration Review assessment of the occupational handl er and 

post-application exposure and residential post-application exposure (spray drift) and risk from 

the registered uses. 

Flufenacet is currently registered for use on the following agricultural crops: corn (field, seed, 

silage, and sweet), grasses grown for seed, soybeans, triticale, and wheat. 

It is HED policy to use the best available data to assess exposure. Several sources of generic 

data were used in this assessment as surrogate data in the absence of chemical-specific data, 

including: Pesticide Handlers Exposure Database Version I. I (PHED I. I); the Agricultural ReEntry Task Force (ARTF); and the Agricultural Handler Exposure Task Force (AHETF) 

database. Some of these data are proprietary, and subject to the data protection provisions of the 

Federal Insecticide, Fungicide, and Rodcnticide Act (FIFRA). 

Note: This memorandum was reviewed by the Exposure Science Advisory Committee 

(ExpoSAC) on February 12, 20 15. 

Page 2 of 33 
Page 3 of 33

Table of Contents

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

2.0 Risk Assessment Conclusions ............................................................................................. 6

2.1 Data Deficiencies and Requirements ............................................................................... 6

3.0 Hazard Characterization....................................................................................................... 7

4.0 Use Profile ......................................................................................................................... 10

5.0 Residential Exposure and Risk Estimates.......................................................................... 11

5.1 Spray Drift...................................................................................................................... 11

5.1.2 Risk Estimates From Lawn Deposition Adjacent to Agricultural Applications ........ 12

5.2 Residential Bystander Post-Application Inhalation Exposure ....................................... 14

6.0 Occupational Exposure and Risk Estimates ...................................................................... 15

6.1 Occupational Handler Exposure/Risk Estimates............................................................ 15

6.2 Occupational Post-application Exposure/Risk Estimates .............................................. 18

6.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates...................... 18

6.2.2 Occupational Post-application Dermal Exposure/Risk Estimates.......................... 19

Appendix A. Summary of Occupational and Residential Non-cancer Algorithms..................... 22

Appendix B. Registered Flufenacet End-Use Products............................................................... 25

Appendix C. Rationale for Requiring TTR and DFR Data ......................................................... 26

Appendix D. Occupational Handler Exposure Tables................................................................. 29
Page 4 of 33

1.0 Executive Summary

HED has conducted an occupational and residential exposure assessment for Registration 

Review of the active ingredient (ai), flufenacet. Flufenacet is an anilide herbicide used to control 

grasses and broadleaf weeds; and is currently registered for use on corn, grasses grown for seed, 

soybeans, triticale, and wheat. This memorandum contains HED’s occupational exposure and 

risk estimates to pesticide handlers (i.e., mixers, loaders, applicators) and to agricultural workers

conducting post-application activities. This assessment also contains a residential postapplication assessment evaluating the exposure resulting from flufenacet drift from agricultural 

applications onto residential areas. 

Use Pattern

Flufenacet is currently formulated as soluble concentrate (SC) and dry flowable (DF) end-use 

products (EPs) containing between 24% and 60% ai. The maximum single application rates for 

each crop or use site range from 0.34 to 0.78 lb ai/A. The registered labels permit application via 

ground equipment and tractor drawn spreaders (for impregnated fertilizer applications) only; use 

of aerial and chemigation application equipment is prohibited. Flufenacet is added to dry bulk 

fertilizers and then applied to the registered crops along with the fertilizer. The labels list a 12-

hour restricted entry interval (REI). Occupational handlers must wear the following personal 

protective equipment (PPE) when handling flufenacet: long sleeved shirt, long pants, chemical 

resistant gloves, shoes and socks. In addition to the PPE listed above, a respirator and coveralls 

are required when mixing/loading EPA Reg. No. 264-765. Chemical resistant aprons are also 

required when mixing/loading and cleaning equipment for EPA Reg. Nos. 264-800 and 264-852 

(co-formulations with isoxaflutole), which are two products classified as restricted use pesticides 

(RUPs). 

Exposure Profile

The occupational handler assessment was completed assuming the labeled maximum single 

application rate for each crop or use site. Based on the currently registered uses of flufenacet, 

the durations of exposure are expected to be both short-term (1 to 30 days) and intermediate-term 

(1 to 6 months) for occupational handlers. Long-term exposures (greater than 6 months) are not 

anticipated based on the currently registered use pattern. 

There are no currently registered residential uses of flufenacet; however, a post-application 

exposure assessment was conducted for adults (dermal) and children 1 to 2 years old (dermal and 

incidental oral) to evaluate potential exposure from spray drift onto residential areas from nearby 

agricultural applications. 

Hazard Characterization

The toxicity database for flufenacet is complete and adequate for risk assessment. In repeateddose oral, dermal, and inhalation studies, the liver was consistently the target organ; however in 

most cases liver effects were not considered adverse. Thyroid hormone levels were also 

consistently depressed in oral, dermal, and inhalation studies, and the studies suggest the thyroid 

effects are secondary to the liver effects. In developmental studies, flufenacet seems to delay 

ossification (especially in the skull), eye opening, and male puberty. Neurotoxic effects were 
Page 5 of 33

also observed in dogs and rats exposed as adults, and in female rats exposed in utero and during 

early postnatal period. After chronic exposure, eye effects were observed in the rat, dog, and 

mouse. Mild anemia was observed in rats exposed orally or via inhalation, and 

methemoglobinemia was observed in rats and mice after chronic oral exposure. Flufenacet is 

considered “not likely to be a human carcinogen”. For the incidental oral and dermal exposures, 

the point of departure (POD) is based on effects observed in the rat developmental neurotoxicity 

study (decreased pup body weight and decreased caudate putamen size in offspring). The effect 

on the caudate putamen size was seen at higher doses than the selected POD; however, the effect 

was not evaluated at the low doses, therefore, a NOAEL was not observed for decreased caudate 

putamen size. The level of concern (LOC) for dermal and incidental oral exposures is 1000 (10x

interspecies, 10x intraspecies, 10x for the lack of a no observed adverse effect level (NOAEL)

and unavailability of comparative thyroid data). The inhalation POD (all durations) is based on 

a route-specific 28-day inhalation study in rats. The LOC for inhalation exposures is 300 which 

includes interspecies (3x) and intraspecies (10x) uncertainty factors, as well as a 10x uncertainty 

factor for the lack of a NOAEL in the study. The interspecies factor was reduced from default 

10x to 3x, because the human equivalent concentration (HEC) calculation completed when using 

a route-specific inhalation study accounts for pharmacokinetic interspecies differences. The 

default intraspecies factor is retained at 10x because the HEC calculation does not account for 

pharmacodynamic intraspecies differences.

Occupational Handler Exposure

There are some occupational handler risk estimates of concern for the registered uses of 

flufenacet at baseline and label-specified PPE. At baseline, occupational dermal margins of 

exposure (MOEs) ranged from 40 to 4,000; and occupational inhalation MOEs ranged from 22 to 

1,400. Some risk estimates are of concern even with engineering controls. 

Occupational Post-Application Exposure

All occupational short- and intermediate-term risk estimates resulted in dermal MOEs of concern 

on day 0 with default dislodgeable foliar residue (DFR) inputs. There are no chemical-specific 

DFR studies available for flufenacet. The dermal post-application MOEs for flufenacet range 

from 88 to 800 on the day of application. The number of days for the MOE to reach the LOC of 

1,000 range from 3 to 23 days for the registered uses of flufenacet. Therefore, the REI of 12 

hours is not adequate and a DFR study on corn or soybeans is required. 

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

inhalation exposure assessment was not performed for flufenacet 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 flufenacet.

Residential Exposure - Spray Drift Assessment

There are no registered residential uses of flufenacet; however, a quantitative non-occupational 

spray drift assessment was conducted. Adult dermal and children’s (1 to < 2 year old) dermal 

and incidental oral risk estimates from indirect exposure to flufenacet related to spray drift 

exceed the LOC at various distances from the edge of the field, depending on spray type/nozzle 

configuration. Results indicate that groundboom application to corn results in the worst-case 
Page 6 of 33

estimate of exposure from drift. However, when using a low boom, and fine to medium/coarse 

sprays, there were no risks of concern estimated at the field’s edge. 

Human Studies Review

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 

PHED 1.1; the AHETF database; and the 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. Descriptions of data sources, as well as guidance on their use, 

can be found at the Agency website1. 

2.0 Risk Assessment Conclusions 

Occupational Handler

There are risks of concern at the label-specified PPE for some occupational handler scenarios 

even at the highest level of appropriate mitigation available (e.g., engineering controls). 

Occupational Post-Application 

All occupational short- and intermediate-term risk estimates resulted in dermal MOEs of concern 

on day 0. Therefore, additional mitigation is required, such as increased REIs to protect workers 

entering treated fields. The days needed following flufenacet application in order for the MOEs 

to be not of concern are provided in Table 6.2.2. 

Spray Drift 

For the registered uses of flufenacet, the dermal MOEs at the edge of the field ranged from 670 

to 8,700 for adults; and combined dermal and incidental oral MOEs ranged from 260 to 3,400 for 

children 1 to < 2 years old. Some scenarios require differing boom heights, spray droplet sizes, 

or distances from the field edge to be not of concern (dermal and incidental oral LOC = 1000). 

2.1 Data Deficiencies and Requirements

Dislodgeable Foliar Residue (DFR) Data: Since the highest estimated occupational postapplication exposure using default DFR values for flufenacet is 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 = 2,000 compared to the LOC of 1,000); EPA is requiring the 40 CFR DFR data. 

Therefore, EPA is requiring the 40 CFR 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. EPA is requesting that DFR studies be submitted on 

 

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

http://www.epa.gov/pesticides/science/post-app-exposure-data.html
Page 7 of 33

corn or soybeans in separate geographic locations. Additionally, a protocol should be submitted 

prior to starting these studies.2 

3.0 Hazard Characterization

The toxicity database for flufenacet is complete and adequate for risk assessment. The 

requirement for a guideline immunotoxicology study has been waived (TXR 0056951, J. Leshin 

2014). The mammalian toxicological database identifies several flufenacet target tissues, 

including liver, eye, blood, and nervous system; changes in thyroid hormones were associated 

with non-adverse liver effects, including metabolic enzyme induction. In developmental studies, 

delayed ossification, especially in the skull, was seen after in utero exposure to flufenacet. In an 

inhalation study, portal of entry effects were observed in the extrathoracic region after exposure 

to flufenacet. Neurotoxic effects were also observed in dogs and rats exposed as adults, and in 

female rats exposed in utero and during early postnatal period. After chronic exposure, eye 

effects were observed in the rat, dog, and mouse. Mild anemia was observed in rats exposed 

orally or via inhalation, and methemoglobinemia was observed in rats and mice after chronic oral 

exposure. Flufenacet is considered “not likely to be a human carcinogen”. 

The dermal POD remains unchanged since the previous risk assessment. However, the 

inhalation and incidental oral PODs have been revised since the previous assessment. For the 

incidental oral and dermal exposures, the POD (lowest observed adverse effect level; LOAEL = 

1.7 mg/kg/day) is based on effects observed in the rat developmental neurotoxicity study 

(decreased pup body weight, delayed eye opening and preputial separation, and decreased 

caudate putamen size and motor activity in adult female offspring). The LOC for dermal and 

incidental oral exposures is 1000 (10x interspecies, 10x intraspecies, 10x for the lack of a 

NOAEL and unavailability of comparative thyroid data). For the inhalation POD (all durations) 

a LOAEL of 0.02 mg/L from a route-specific 28-day inhalation study in rats was used to 

calculate a human-equivalent dose (HED) of 0.143 mg/kg/day. The LOC for inhalation 

exposures is 300 which includes interspecies (3x) and intraspecies (10x) uncertainty factors, as 

well as a 10x uncertainty factor for the lack of a NOAEL in the study. The interspecies factor 

was reduced from default 10x to 3x, because the HEC calculation accounts for pharmacokinetic

interspecies differences. The default intraspecies factor is retained at 10x because the HEC 

calculation does not account for pharmacodynamic intraspecies differences.

Because the inhalation POD is based on a route-specific study, and the incidental oral and dermal 

PODs are based on oral studies, the inhalation and dermal risk estimates for flufenacet are not 

combined into a total risk estimate. 

Acute Toxicity

The acute toxicity of flufenacet is summarized in Table 3.1. Flufenacet has low acute toxicity 

via the oral (Toxicity Category III), dermal (Toxicity Category III), and inhalation routes 

 

2 http://www.ecfr.gov/cgi-bin/textidx?SID=a5983c2e243fca24493fbe7a02254834&mc=true&node=se40.24.158_11070&rgn=div8
Page 8 of 33

(Toxicity Categories IV). Flufenacet produces slight eye irritation (Toxicity Category IV) and is 

not a dermal irritant or sensitizer. 

Table 3.1. Acute Toxicity Profile – Flufenacet.

Guideline No. Study Type MRID(s) Results Toxicity Category

870.1100 Acute oral rat 43441104 LD50 = 1617 mg/kg (M)

 589 mg/kg (F) III

870.1200 Acute dermal rat 43441106 LD50 ≥ 2000 mg/kg III

870.1300 Acute inhalation rat 43441108 LC50 > 3.74 mg/L IV

870.2400 Acute eye irritation rabbit 43850017 slight eye irritant IV

870.2500 Acute dermal irritation rabbit 43850023 not a dermal irritant IV

870.2600 Skin sensitization guinea pigs –

Buehler method 43850025 not a dermal sensitizer N/A

870.2600 Skin sensitization guinea pigs –

Maximization method 43877601 dermal sensitizer N/A

Table 3.2. Summary of Toxicological Doses and Endpoints for Flufenacet for Use in Occupational and 

Non-Occupational Human Health Risk Assessments.

Exposure/ 

Scenario Point of Departure

Uncertainty

/FQPA 

Safety 

Factors

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Incidental Oral 

Short-Term (1-30 

days) and 

Intermediate-Term 

(1-6 months)

LOAEL= 1.7

mg/kg/day

UFA= 10x

UFH= 10x

FQPA SF= 

10x (UFL)

Residential 

LOC for MOE 

= 1000

Developmental neurotoxicity 

study in rats. LOAEL = 1.7 

mg/kg/day based on decreased 

pup body weight, delayed eye 

opening, delayed preputial 

separation, and decreased caudate 

putamen size.

Dermal Short-Term 

(1-30 days) and 

Intermediate-Term 

(1-6 months)

LOAEL= 1.7

mg/kg/day

UFA= 10x

UFH= 10x

UFL = 10x

Occupational

LOC for MOE 

= 1000

Residential 

LOC for MOE 

= 1000

Developmental neurotoxicity 

study in rats. LOAEL = 1.7 

mg/kg/day based on decreased 

pup body weight, delayed eye 

opening, delayed preputial 

separation, and decreased caudate 

putamen size.
Page 9 of 33

Table 3.2. Summary of Toxicological Doses and Endpoints for Flufenacet for Use in Occupational and 

Non-Occupational Human Health Risk Assessments.

Exposure/ 

Scenario Point of Departure

Uncertainty

/FQPA 

Safety 

Factors

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Inhalation ShortTerm (1-30 days)

and IntermediateTerm (1-6 months)

LOAEL = 0.02 mg/L

HEC = 0.00252 mg/L

f = 8.3 L/min

HED =

0.143 mg/kg/day

f = 16.7 L/min

HED =

0.289 mg/kg/day

f =

29 L/min

HED =

0.501 mg/kg/day

UFA= 3x

UFH= 10x

UFL = 10x

Occupational

LOC for MOE 

= 300

Residential = 

N/A

28-day inhalation toxicity study 

in rats. LOAEL = 0.2 mg/kg/day 

based on portal of entry effects 

(nasal cavity goblet cell 

hyperplasia in males and larynx 

inflammatory infiltrate in 

females) and increased incidence 

of sperm-related lesions of the 

testis and epididymis.

Cancer (oral, 

dermal, inhalation)

Classification: Not likely to be a human carcinogen (RfD Peer Review Committee report, 

7/16/1997).

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). UFL = use of a LOAEL to extrapolate a 

NOAEL. FQPA SF = FQPA Safety Factor. MOE = margin of exposure. LOC = level of concern. N/A = not 

applicable. HEC = Human Equivalent Concentration. HED = Human Equivalent Dose. f = breathing rate 

associated with a specific activity.

Absorption: No dermal absorption data are available. However, for route-to-route extrapolation 

a factor of 4% has been established based on a comparison between the LOAEL of 6 mg/kg/day 

in the 90-day feeding study in rats (MRID 43743401) and a LOAEL of 150 mg/kg/day in the 21-

day dermal study in rats (MRID 43850027); endpoints in both studies are based on decreased 

thyroid hormone levels in plasma (K Raffaele, TXR 0051853, 4/23/2003; TXR 0013638, 

02/19/1997). The 4% factor is appropriate for use in the absence of dermal absorption data 

because it accounts for the differential effects between the dermal and oral routes of exposure, 

and it characterizes the differences between dermal and oral absorption together with differences 

in other processes that occur after flufenacet enters the body through either route, such as 

metabolism and transport to the target organs.

Body Weight: Since the dermal POD is based on developmental and/or fetal effects, the adult

body weight appropriate for dermal assessments is 69 kg. Since the inhalation POD is not based 

on developmental and/or fetal effects, the adult body weight appropriate for inhalation 

assessments is 80 kg. For the spray drift assessment, a default body weight of 11 kg was used 

for children 1 to < 2 years old. 
Page 10 of 33

4.0 Use Profile 

Flufenacet is currently formulated into seven liquid SC and DF EPs containing between 24% and 

60% ai. Flufenacet is currently registered on field, silage, seed, and sweet corn; grass grown for 

seed; soybeans; triticale; and wheat. The maximum single application rates range from 0.34 to 

0.78 lb ai/acre for the registered uses. Most of the labels only allow for one application of 

flufenacet per year; however, EPA Reg. No. 264-766 allows for multiple applications to triticale 

and wheat (RTI = 21 days) but it restricts the application amount to 0.34 lb ai/A per season. All 

labels list a 12-hour REI. Occupational handlers must wear the following PPE when handling 

flufenacet: long sleeved shirt, long pants, chemical resistant gloves, shoes and socks. In addition 

to the PPE listed above, a respirator and coveralls are required when mixing/loading EPA Reg. 

No. 264-765. Chemical resistant aprons are also required when mixing/loading and cleaning 

equipment for EPA Reg. Nos. 264-800 and 264-852 (co-formulations with isoxaflutole).

The uses and application rates are summarized in Table 4.1. 

Table 4.1. Summary of Directions for Use of Flufenacet.

Applic. Timing, Type, and 

Equip.

Max. 

Applic. 

Rate

Max. No. 

Applic. per 

Season

Max. 

Seasonal 

Applic. Rate 

RTI1

(days) Use Directions and Limitations

Corn (field, silage, seed, and sweet)

Groundboom, Dry Bulk 

Fertilizer

0.78 lb 

ai/A 1 0.78 lb ai/A N/A Preplant surface, preplant incorporated, or preemergent application only

Dry Bulk Fertilizer3 7.88 lb 

ai/ton 1 7.88 lb ai/ton NA Use a minimum of 200 pounds and a maximum of 450 pounds per acre

Soybeans

Groundboom 0.46 lb 

ai/A 1 0.46 lb ai/A N/A Preplant surface, preplant incorporated, or preemergent application only

Dry Bulk Fertilizer3 4.56 lb 

ai/ton 1 4.56 lb ai/ton NA Use a minimum of 200 pounds and a maximum of 450 pounds per acre

Triticale & Wheat

Groundboom 0.34 lb 

ai/A N/A2 0.34 lb ai/A 21 Preemergent to early postemergent applications only

Grass Grown for Seed

Groundboom 0.44 lb 

ai/A 1 0.44 lb ai/A N/A

Allow a minimum of 4 weeks between 

application of flufenacet and other 

photosynthetic inhibitor herbicides

1. RTI = Re-Treatment Interval.

2. Sequential applications are allowed to triticale and wheat on EPA Reg. No. 264-766. However, the maximum seasonal 

application rate is 0.34 lb ai/A. Reduced maximum single application rates must be used if multiple applications per season 

are required. 

3. To calculate the dry bulk fertilizer rate: Application Rate (fl oz product/A) × (1 gallon product/128 fl oz product) × (lb 

ai/gallon product) × (1 A/200 lb fertilizer) × (2000 lb fertilizer/1 ton fertilizer) = lb ai/ton fertilizer.
Page 11 of 33

5.0 Residential Exposure and Risk Estimates

There are no proposed or registered residential uses of flufenacet at this time; however, there are 

existing agricultural uses that could result in potential drift onto residential areas and result in 

potential post-application exposure. 

5.1 Spray Drift

Off-target movement of pesticides can occur via many types of pathways and it is governed by a 

variety of factors. Sprays that are released and do not deposit in the application area end up offtarget and can lead to exposures to those it may directly contact. They can also deposit on 

surfaces where contact with residues can eventually lead to exposures (e.g., children playing on 

lawns where residues have deposited next to treated fields). The potential risk estimates from 

these residues can be calculated using drift modeling coupled with methods employed for 

residential risk assessments for turf products.

The approach to be used for quantitatively incorporating spray drift into risk assessment is based 

on a premise of compliant applications which, by definition, should not result in direct exposures 

to individuals because of existing label language and other regulatory requirements intended to 

prevent them.3 Direct exposures would include inhalation of the spray plume or being sprayed 

directly. Rather, the exposures addressed here are thought to occur indirectly through contact 

with impacted areas, such as residential lawns, when compliant applications are conducted. 

Given this premise, exposures for children (1 to < 2 years old) and adults who have contact with 

turf where residues are assumed to have deposited via spray drift thus resulting in an indirect 

exposure are the focus of this analysis analogous to how exposures to turf products are 

considered in risk assessment. 

In order to evaluate the drift potential and associated risks, an approach based on drift modeling 

coupled with techniques used to evaluate residential uses of pesticides was utilized. Essentially, 

a residential turf assessment based on exposure to deposited residues has been completed to 

address drift from the agricultural applications of flufenacet. In the spray drift scenario, the 

deposited residue value was determined based on the amount of spray drift that may occur at 

varying distances from the edge of the treated field using the AgDrift (v2.1.1) model and the 

Residential Exposure Assessment Standard Operating Procedures Addenda 1: Consideration of 

Spray Drift Policy. Once the deposited residue values were determined, the remainder of the

spray drift assessment was based on the algorithms and input values specified in the recently 

revised (2012) Standard Operating Procedures For Residential Risk Assessment (SOPs). 

A screening approach was developed based on the use of the AgDrift model in situations where 

specific label guidance that defines application parameters is not available.4 AgDrift is 

appropriate for use only when applications are made by aircraft, airblast orchard sprayers, and 

groundboom sprayers. When AgDrift was developed, a series of screening values (i.e., the Tier 

1 option) were incorporated into the model and represent each equipment type and use under 

 

3 This approach is consistent with the requirements of the EPA’s Worker Protection Standard.

4http://www.epa.gov/pesticides/science/models_pg.htm
Page 12 of 33

varied conditions. The screening options specifically recommended in this methodology were 

selected because they are plausible and represent a reasonable upper bound level of drift for 

common application methods in agriculture. These screening options are consistent with how 

spray drift is considered in a number of ecological risk assessments and in the process used to 

develop drinking water concentrations used for risk assessment. In all cases, each scenario is to 

be evaluated unless it is not plausible based on the anticipated use pattern (e.g., herbicides are 

not typically applied to tree canopies) or specific label prohibitions (e.g., aerial applications are 

not allowed). Section 5.1.2 provides the screening level drift related risk estimates. 

In many cases, risks are of concern when the screening level estimates for spray drift are used as 

the basis for the analysis. In order to account for this issue and to provide additional risk 

management options additional spray drift deposition fractions were also considered. These drift 

estimates represent plausible options for pesticide labels

5.1.2 Risk Estimates From Lawn Deposition Adjacent to Agricultural Applications

Flufenacet is used on numerous agricultural crops and can only be applied via groundboom 

equipment. The spray drift risk estimates are based on an estimated deposited residue 

concentration as a result of the screening level agricultural application scenarios. The 

recommended drift scenario screening level options are listed below: 

 Groundboom applications are based on the AgDrift option for high boom height and 

using very fine to fine spray type using the 90th percentile results. 

The highest exposure resulted from drift following flufenacet applications to corn using 

groundboom equipment. There were dermal risk estimates of concern at the field edge for adults 

following application to corn, and dermal and incidental oral combined risk estimates of concern 

for children 1 to <2 years old following application to corn, soybeans, and grasses grown for 

seed. However, if a low boom or medium/coarse sprays are used or the distance from the field 

edge is increased, these MOEs are not of concern. See Tables 5.1.2.1 and 5.1.2.2 for detailed

results.

Table 5.1.2.1. Adult Dermal Risk Estimates (MOEs) Related to Spray Drift Exposure to Flufenacet from 

the Registered Agricultural Uses. 

Application 

Type

Spray Type/Nozzle 

Configuration

Appl. Rate 

(lb ai/A) TTR (μg/cm2

)

2 At Edge (LOC 

= 1000)

10 Feet (LOC = 

1000)

Corn

Groundboom

High Boom Very 

fine to Fine

0.78 0.086697

670 1,300

Low Boom Very 

fine to Fine 1,500

N/A High Boom Fine to 

Medium/Coarse 2,600

Low Boom Fine to 

Medium/Coarse 3,800

Soybeans
Page 13 of 33

Table 5.1.2.1. Adult Dermal Risk Estimates (MOEs) Related to Spray Drift Exposure to Flufenacet from 

the Registered Agricultural Uses. 

Application 

Type

Spray Type/Nozzle 

Configuration

Appl. Rate 

(lb ai/A) TTR (μg/cm2

)

2 At Edge (LOC 

= 1000)

10 Feet (LOC = 

1000)

Groundboom

High Boom Very 

fine to Fine

0.46 0.051129

1,100

N/A

Low Boom Very 

fine to Fine 2,500

High Boom Fine to 

Medium/Coarse 4,300

Low Boom Fine to 

Medium/Coarse 6,400

Grass Grown for Seed

Groundboom

High Boom Very 

fine to Fine

0.44 0.048906

1,200

N/A

Low Boom Very 

fine to Fine 2,600

High Boom Fine to 

Medium/Coarse 4,500

Low Boom Fine to 

Medium/Coarse 6,700

Wheat/Triticale

Groundboom

High Boom Very 

fine to Fine

0.34 0.037791

1,500

Low Boom Very N/A

fine to Fine 3,400

High Boom Fine to 

Medium/Coarse 5,900

Low Boom Fine to 

Medium/Coarse 8,700

1 HED’s default assumption that 10% 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.

Table 5.1.2.2. Children 1 to < 2 Years Old Combined Dermal and Hand-to-Mouth Risk Estimates (MOEs) 

Related to Spray Drift Exposure to Flufenacet from the Registered Agricultural Uses. 

Application 

Type

Spray 

Type/Nozzle 

Configuration

Appl. 

Rate 

(lb 

ai/A)

TTR (μg/cm2)

1

At Edge 

(LOC = 

1000)

10 Feet 

(LOC = 

1000)

25 Feet 

(LOC = 

1000)

50 Feet 

(LOC = 

1000)

Corn

Groundboom

High Boom Very 

fine to Fine

0.78 0.086697

260 520 870 1,400

Low Boom Very 

fine to Fine 570 1,500

High Boom Fine N/A N/A

to 

Medium/Coarse

990 2,600
Page 14 of 33

Table 5.1.2.2. Children 1 to < 2 Years Old Combined Dermal and Hand-to-Mouth Risk Estimates (MOEs) 

Related to Spray Drift Exposure to Flufenacet from the Registered Agricultural Uses. 

Application 

Type

Spray 

Type/Nozzle 

Configuration

Appl. 

Rate 

(lb 

ai/A)

TTR (μg/cm2)

1

At Edge 

(LOC = 

1000)

10 Feet 

(LOC = 

1000)

25 Feet 

(LOC = 

1000)

50 Feet 

(LOC = 

1000)

Low Boom Fine 

to 

Medium/Coarse

1,500 N/A

Soybeans

Groundboom

High Boom Very 

fine to Fine

0.46 0.051129

440 880 1,500

N/A

Low Boom Very 

fine to Fine 970 2,600

N/A

High Boom Fine 

to 

Medium/Coarse

1,700

N/A

Low Boom Fine 

to 

Medium/Coarse

2,500

Grass Grown for Seed

Groundboom

High Boom Very 

fine to Fine

0.44 0.048906

460 920 1,500

N/A

Low Boom Very 

fine to Fine 1,000

N/A N/A

High Boom Fine 

to 

Medium/Coarse

1,800

Low Boom Fine 

to 

Medium/Coarse

2,600

Wheat/Triticale

Groundboom

High Boom Very 

fine to Fine

0.34 0.037791

600 1,200

N/A N/A

Low Boom Very 

fine to Fine 1,300

N/A

High Boom Fine 

to 

Medium/Coarse

2,300

Low Boom Fine 

to 

Medium/Coarse

3,400

1 HED’s default assumption that 10% 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.

5.2 Residential Bystander Post-Application Inhalation Exposure

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 
Page 15 of 33

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 has evaluated the SAP report and has developed a Volatilization Screening Tool and a 

subsequent Volatilization Screening Analysis 

(http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219). 

During Registration Review, the agency will utilize this analysis to determine if data (i.e., flux 

studies, route-specific inhalation toxicological studies) or further analysis is required for 

flufenacet.

6.0 Occupational Exposure and Risk Estimates

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 and current labeling, types of equipment and techniques 

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 

scenarios listed in Table 6.1.1. 

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.

Application Rate: The maximum single application rates are listed in Table 4.1. 

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 PHED 1.1, the AHETF 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 Table5”, 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 website6.

 

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

6 Available: http://www.epa.gov/pesticides/science/handler-exposure-data.html
Page 16 of 33

Area Treated or Amount Handled: The amount/area treated for each scenario is listed in 

Appendix D. 

Exposure Duration: HED classifies exposures from 1 to 30 days as short-term and exposures 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 agricultural uses, 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, there may be a large agribusiness and/or 

commercial applicators who may apply a product over a period of weeks (e.g., completing 

multiple applications for multiple clients within a region). 

For flufenacet, based on the proposed use, short- and intermediate-term exposures are expected. 

However, since the short- and intermediate-term inhalation and dermal PODs are the same for 

both durations, the assessment is protective of both durations. 

Mitigation/Personal Protective Equipment: Estimates of dermal and inhalation exposure were 

calculated for various levels of PPE. 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). Occupational handlers must wear the following PPE when handling 

flufenacet: long sleeved shirt, long pants, chemical-resistant gloves, shoes and socks. In addition 

to the PPE listed above, a respirator and coveralls are required when mixing/loading EPA Reg. 

No. 264-765. Chemical resistant aprons are also required when mixing/loading and cleaning 

equipment for EPA Reg. Nos. 264-800 and 264-852 (co-formulations with isoxaflutole).

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 A.

Summary of Occupational Handler Non-Cancer Exposure and Risk Estimates

There are some occupational handler risk estimates of concern for the registered uses of 

flufenacet at baseline, PPE, and engineering control mitigation. The level of concern (LOC) for 

occupational handler dermal risk estimates is a MOE of 1,000. The LOC for occupational 

handler inhalation risk estimates is a MOE of 300. At baseline, occupational dermal MOEs 

ranged from 40 to 4,000; and occupational inhalation MOEs ranged from 22 to 1,400. 

The following scenarios are not of concern at baseline PPE: 

 Applying sprays via groundboom equipment to sod; and 

 Applying flufenacet in on-farm impregnated dry bulk fertilizers to soybeans.

The following scenario requires gloves to be not of concern: 

 Mixing/loading liquid flufenacet to produce impregnated dry bulk fertilizers on-farm to 
Page 17 of 33

treat soybeans.

The following scenarios require the use of a PF5 respirator to be not of concern: 

 Mixing/loading dry flowable flufenacet for groundboom application to sod; and

 Applying flufenacet sprays via groundboom equipment to corn.

The following scenario requires gloves and a double layer of clothing to be not of concern: 

 Mixing/loading dry flowable flufenacet for groundboom application to wheat. 

The following scenario requires gloves, a double layer of clothing, and a PF10 respirator to be 

not of concern: 

 Mixing/loading liquid flufenacet for groundboom application to soybeans.

The following scenarios require the use of engineering controls to be not of concern: 

 Mixing/loading dry flowable flufenacet to produce impregnated dry bulk fertilizers onfarm to treat corn and soybeans;

 Mixing/loading dry flowable flufenacet for groundboom application to corn and 

soybeans; 

 Mixing/loading liquid flufenacet to produce impregnated dry bulk fertilizers on-farm to 

treat corn; and

 Mixing/loading liquid flufenacet for groundboom application to corn. 

The following scenarios are of concern at all levels of PPE (including engineering controls): 

 Mixing/loading dry flowable flufenacet to produce impregnated dry bulk fertilizers 

commercially to treat corn and soybeans; and

 Mixing/loading liquid flufenacet to produce impregnated dry bulk fertilizers 

commercially to treat corn and soybeans.

The use of gloves when handling flufenacet is already required on the flufenacet labels. In 

addition to gloves, a respirator and coveralls are already required when mixing/loading EPA 

Reg. No. 264-765. Chemical resistant aprons are also required when mixing/loading and 

cleaning equipment for EPA Reg. Nos. 264-800 and 264-852. Therefore, HED recommends that 

PRD require the appropriate PPE on all relevant labels so that the scenarios above are not of 

concern. For the scenarios of concern with the maximum PPE level, PRD should evaluate 

additional mitigation options with the Registrant.

A summary of the occupational handler scenarios and the PPE required to be not of concern for 

each scenario is provided in Table 6.1.1. Detailed scenarios and exposure estimates are provided 

in Appendix D. 

Table 6.1.1. Summary of PPE Required (if any) for MOEs to be Not of Concern for Occupational Handlers of Flufenacet.

Exposure Scenario and Formulation Crop or Target

PPE Required to be not of concern 

(Dermal LOC = 1000) 

(Inhalation LOC = 300)

Mixer/Loader
Page 18 of 33

Table 6.1.1. Summary of PPE Required (if any) for MOEs to be Not of Concern for Occupational Handlers of Flufenacet.

Exposure Scenario and Formulation Crop or Target

PPE Required to be not of concern 

(Dermal LOC = 1000) 

(Inhalation LOC = 300)

Mixing/Loading Dry Flowables for Commercial Treatment To 

Produce Impregnated Fertilizers

Corn

X1

Soybeans

Mixing/Loading Dry Flowables for On-Farm Treatment To 

Produce Impregnated Fertilizers

Corn

Engineering Controls Soybeans

Mixing/Loading Dry Flowables for Groundboom Application

Sod Gloves + PF5 Respirator

Corn Engineering Controls

Soybeans Engineering Controls

Wheat Double Layer Clothing + Gloves + 

PF10

Mixing/Loading Liquids for Commercial Treatment To Produce 

Impregnated Fertilizers

Corn

X1

Soybeans

Mixing/Loading Liquids for On-Farm Treatment To Produce 

Impregnated Fertilizers

Corn Engineering Controls

Soybeans Gloves

Mixing/Loading Liquids for Groundboom Application Corn EC Soybeans

Applicator

Applying Sprays via Groundboom Equipment

Sod None (Baseline)

Corn Gloves + PF5 Respirator

Soybeans Gloves

Wheat Gloves

Applying Impregnated Dry Bulk Fertilizer - Commercial 

Treatment

Corn

Soybeans PF5 Respirator

Applying Impregnated Dry Bulk Fertilizer - On-Farm Treatment Corn

Soybeans None (Baseline)

1. Scenarios of concern with maximum PPE (engineering controls). PRD should evaluate other mitigation options (e.g., reduced 

application rates, etc.) with the Registrant. 

6.2 Occupational Post-application Exposure/Risk Estimates

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. Post-application exposure levels vary over time and depend on such things as the 

type of activity, the nature of the crop or target that was treated, the type of pesticide application, 

and the chemical’s degradation properties. In addition, the timing of pesticide applications, 

relative to harvest activities, can greatly reduce the potential for post-application exposure.

6.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates

There are multiple potential sources of post-application 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 
Page 19 of 33

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 has 

evaluated the SAP report and has developed a Volatilization Screening Tool and a subsequent 

Volatilization Screening Analysis (http://www.regulations.gov/#!docketDetail;D=EPA-HQOPP-2014-0219). During Registration Review, the agency will utilize this analysis to determine 

if data (i.e., flux studies, route-specific inhalation toxicological studies) or further analysis is 

required for flufenacet.

In addition, the Agency is continuing to evaluate the available post-application inhalation 

exposure data generated by the Agricultural Reentry Task Force. Given these two efforts, the 

Agency will continue to identify the need for and, subsequently, the way to incorporate 

occupational post-application inhalation exposure into the agency's risk assessments.

6.2.2 Occupational Post-application Dermal Exposure/Risk Estimates

Occupational Post-application Dermal Exposure Data and Assumptions

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

post-application risk assessments. Each assumption and factor is detailed below on an individual 

basis.

Exposure Duration: HED classifies exposures from 1 to 30 days as short-term and exposures 30 

days to six months as intermediate-term. For flufenacet, based on the proposed use, only shortand intermediate-term post-application exposures are expected. However, since the short- and 

intermediate-term dermal POD is the same, it is protective of both durations. 

Transfer Coefficients: It is the policy of HED to use the best available data to assess postapplication exposure. Sources of generic post-application data, used as surrogate data in the 

absence of chemical-specific data, are derived from 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 ExpoSAC Policy 37” which, along with 

additional information about the ARTF data, can be found at the Agency website8. Table 6.2.2 

provides a summary of the anticipated post-application activities and associated transfer 

coefficients for the proposed crops/use sites. 

For flufenacet, because it is applied only early in the crop growth cycle for the agricultural crops 

(pre-emergent, or early post-emergent applications), only post-application exposure to low crop 

heights and minimum foliage density was evaluated for corn, soybeans, and wheat. Hand 

weeding was not evaluated because flufenacet is an herbicide used to control weeds and grasses; 

therefore, hand weeding the field would not be necessary. 

 

7 Available: http://www.epa.gov/pesticides/science/exposac_policy3.pdf

8 Available: http://www.epa.gov/pesticides/science/post-app-exposure-data.html
Page 20 of 33

However, flufenacet can be applied to established grasses grown for seed; therefore all crop 

heights and foliage densities were evaluated. 

Application Rate: A summary of the registered application rates for flufenacet is provided in 

Table 4.1. 

Exposure Time: The average occupational workday is assumed to be 8 hours. 

Dislodgeable Foliar Residues: Chemical-specific dislodgeable foliar residue data have not been 

submitted for flufenacet. 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.

Dislodgeable Foliar Residue (DFR) Data: Since the highest estimated occupational postapplication exposure using default DFR values for flufenacet is 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 = 2,000 compared to the LOC of 1,000); EPA is requiring the 40 CFR DFR data. 

Therefore, EPA is requiring the 40 CFR 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. For additional information on this data requirement, see 

Appendix C.

Occupational Post-application Non-Cancer Dermal Exposure and Risk Estimate Equations

The algorithms used to estimate non-cancer exposure and dose for occupational post-application 

workers can be found in Appendix A.

Occupational Post-application Non-Cancer Dermal Risk Estimates

A summary of the occupational dermal post-application MOEs for the registered uses of 

flufenacet are provided in Table 6.2.2. The LOC for occupational post-application risk is a MOE 

of 1,000. All occupational short- and intermediate-term risk estimates resulted in dermal MOEs 

of concern on day 0, except for sod maintenance (LOC = 1,000). The dermal post-application 

MOEs for flufenacet range from 88 to 800 on the day of application. The days to reach an MOE 

of 1,000 for each activity are listed in Table 6.2.2. Therefore, HED recommends that PRD 

require the appropriate REIs on all relevant labels to address these concerns. 

Table 6.2.2. Occupational Post-application Non-Cancer Exposure and Risk Estimates for Flufenacet.

Crop/Site Activities Transfer 

Coefficient (cm2/hr) DFR/TTR1 Dermal Dose (mg/kg/day)2 MOE3

Days for MOE to 

Reach LOC of 

1,000

Corn

Scouting 210

2.19

0.0021 800 3

Hand-Set Irrigation 1,900 0.019 88 23

Grasses 

Grown for 

Seed*

Hand-Set Irrigation 1,900 1.23 0.011 160 18

Scouting 1,100 1.23 0.0063 270 13

Soybean Scouting 1,100 1.29 0.0066 260 13
Page 21 of 33

Table 6.2.2. Occupational Post-application Non-Cancer Exposure and Risk Estimates for Flufenacet.

Crop/Site Activities Transfer 

Coefficient (cm2/hr) DFR/TTR1 Dermal Dose (mg/kg/day)2 MOE3

Days for MOE to 

Reach LOC of 

1,000

Wheat Scouting 1,100 0.95 0.0049 350 10

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 (used for corn, soybeans, 

wheat); TTR = Application Rate × F × (1-D)t × 4.54E8 μg/lb × 2.47E-8 acre/cm2; where F = 0.1 and D = 0.10 per day (used for sod). 

2 Daily Dermal Dose = [DFR/TTR (μg/cm2) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption (4.0 %)]  BW (69 kg).

3 MOE = POD (1.7 mg/kg/day) / Daily Dermal Dose. 

* The post-application exposure inputs for “forage crops” was used as a surrogate. 

Restricted Entry Interval

The REI specified on the proposed label is based on the acute toxicity of flufenacet. Flufenacet

is classified as Toxicity Category III via the dermal route and Toxicity Category IV for skin 

irritation potential. It is not a skin sensitizer. Short- and intermediate-term post-application risk 

estimates were not a concern on day 0 (12 hours following application) for activities related to

sod production. However, there were risk estimates of concern related to scouting and hand-set 

irrigation in corn, and scouting for soybeans and wheat. Therefore, HED is recommending that 

the REIs be revised on the label to address those concerns.
Page 22 of 33

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

Occupational Non-cancer Handler Algorithms

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 registered 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).

Occupational Non-cancer Post-application Algorithms
Page 23 of 33

Potential daily exposures for occupational post-application workers are calculated using the 

following formulas:

DFRt=AR * F* (1-D)t* (4.54E8

ug

lb) * (2.47E-8

A

cm2

)

where:

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

AR = application rate (lb ai/acre),

F = fraction of ai retained on foliage or 25% (unitless),

D = fraction of residue that dissipates daily or 10% (unitless), and

t = number of days after application day (days).

E=TC * DFR t* ET * 0.001

mg

ug

where:

E = exposure (mg ai/day),

TC = transfer coefficient (cm2/hr),

DFRt = dislodgeable foliar residue on day “t” (μg/cm2), and

ET = exposure time (hours/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 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 dose received by occupational post-application workers is compared to the 

appropriate POD (i.e., NOAEL) to assess the risk to occupational post-application workers. All 

MOE values are calculated using the following formula:

MOE= 

POD

ADD

where:
Page 24 of 33

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 25 of 33

Appendix B. Registered Flufenacet End-Use Products

Table B.1. Registered Flufenacet End-Use Products.

EPA Reg. No. Formulation 

Type Product Label Name Company

264-819 SC DEFINETM SC HERBICIDE

Bayer CropScience

264-818 SC Flufenacet 500 SC FLOWABLE 

HERBICIDE

264-800 DF EpicTM DF Herbicide

264-765 DF DEFINETM DF HERBICIDE

264-852 SC Flufenacet & Isoxaflutole SC Herbicide

264-771 DF DomainTM DF Herbicide

264-766 DF Axiom® DF Herbicide
Page 26 of 33

Appendix C. Rationale for Requiring TTR and DFR Data 

Turf Transferable Residue (TTR): In accordance with 40 CFR 158, TTR data are required for all 

occupational (e.g., sod farms, golf courses, parks, and recreational areas) or residential turf uses

that could result in post-application exposure to turf. In the absence of chemical-specific TTR 

data, EPA uses default values. The 2012 Standard Operating Procedures for Residential 

Pesticide Exposure Assessment includes an analysis of all TTR data, available at the time, which 

resulted in the selection of revised liquid and granular default values for the fraction of the 

application rate available for transfer after a turf application (FAR). These values are based on an 

analysis of 59 TTR studies performed with the Modified California Roller Method (36 studies 

using liquids, 11 studies using wettable powders/water dispersible granules, and 12 studies using 

granules). The liquid results (N=131) indicate a range of FAR values from 0.0005% to 6.1% and 

the granular results (N=37) indicate a range of 0.00064% to 0.69%. In both the liquid and 

granular 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 

TTR data for a single chemical. HED selected 1% and 0.2% as high-end default values for 

liquid and granular products, respectively. Because TTR data are not available for flufenacet, 

EPA is using the default value of [appropriate value for liquid or granular product]. Although 

there may be a small degree of uncertainty in the use of the default TTR value for flufenacet (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 turf assessment 

methodology will more than compensate for this potential uncertainty (i.e., the methodology is 

likely to overestimate exposure by a factor greater than the factor than the highest measured FAR

values exceed the defaults ). For example, when assessing residential post-application turf 

exposure, 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, the grass is not mowed, etc); individuals perform the same 

post-application activities performed in the turf transfer coefficient study day after day (e.g., 

tumbling, playing on turf with toys, etc.); and individuals engage in these post-application 

activities for a high-end amount of time every day that is represented by data reflecting time 

children spend outdoors and not specifically engaged in activities on turf, when in actuality 

children do not spend all of their outdoor time on turf and high-end levels of activity will not 

occur every day.

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. 

Since the estimated residential turf post-application exposure for sod using default TTR values 

for flufenacet is not minimal in comparison to the level of concern (i.e., the calculated MOE is 

not greater than 10 times higher than the level of concern, MOE = 10,000 compared to the LOC 

of 1,000), future refinements of this post-application exposure for flufenacet may be necessary 
Page 27 of 33

due to increased use of flufenacet or advances in EPA risk assessments. Therefore, EPA is 

requiring the 40CFR TTR data requirement to facilitate any necessary exposure assessments 

refinements and to further EPA’s general understanding of the availability of turf transferable 

pesticide residues.

Dislodgeable Foliar Residue (DFR): 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 postapplication 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 flufenacet, 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 flufenacet (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 this potential uncertainty. For example, when assessing residential and 

occupational post-application 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. 

Since the highest estimated occupational post-application exposure using default DFR values for 

flufenacet 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 = 2,000 compared to the LOC of 

1,000); EPA is requiring the 40 CFR DFR data. Therefore, EPA is requiring the 40CFR DFR 
Page 28 of 33

data requirement to facilitate any necessary exposure assessments refinements and to further 

EPA’s general understanding of the availability of dislodgeable foliar pesticide residues.
Page 29 of 33

Appendix D. Occupational Handler Exposure Tables 

Table D.1. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet at Baseline PPE.

Exposure Scenario Crop or 

Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2 (lb 

ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

Baseline* Baseline*

Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 

300)

Mixer/Loader

Mixing/Loading Dry Flowables for 

Commercial Treatment with 

Impregnated Fertilizers

Corn

9.8 0.24

7.88 lb 

ai/ton 960 tons

0.043 40 0.02228 22

Soybeans 4.56 lb 

ai/ton 0.0249 68 0.0131 38

Mixing/Loading Dry Flowables for 

On-Farm Treatment with 

Impregnated Fertilizers

Corn

227 8.96

0.78

160 acres

0.0164 100 0.0140 21

Soybeans 0.46 0.00968 180 0.00824 35

Mixing/Loading Dry Flowables for 

Groundboom Application

Sod

227 8.96

0.44 80 acres 0.00463 370 0.00394 73

Corn 0.78

200 acres

0.0205 83 0.0175 17

Soybeans 0.46 0.0121 140 0.0103 28

Wheat 0.34 0.00893 190 0.00761 38

Mixing/Loading Liquids for 

Commercial Treatment with 

Impregnated Fertilizers

Corn

8.6 0.083

7.88 lb 

ai/ton 960 tons

0.0377 45 0.00785 64

Soybeans 4.56 lb 

ai/ton 0.0218 48 0.00454 110

Mixing/Loading Liquids for OnFarm Treatment with Impregnated 

Fertilizers

Corn

220 0.219

0.78

160 acres

0.0159 110 0.000341 850

Soybeans 0.46 0.00939 180 0.000201 1,400

Mixing/Loading Liquids for 

Groundboom Application

Corn 220 0.219 0.78 200 acres 0.0199 85 0.000428 680

Soybeans 0.46 0.0117 150 0.000251 1,200

Applicator

Applying Sprays via Groundboom 

Equipment

Sod

78.6 0.34

0.44 80 acres 0.00161 1,100 0.00150 950

Corn 0.78

200 acres

0.00713 240 0.000662 220

Soybeans 0.46 0.00419 410 0.000391 370

Wheat 0.34 0.0031 550 0.000289 490

Applying Impregnated Dry Bulk 

Fertilizer - Commercial Treatment

Corn 9.9 1.2 0.78 320 acres 0.00143 1,200 0.00375 130

Soybeans 0.46 0.000846 2,000 0.00221 230

Applying Impregnated Dry Bulk 

Fertilizer - On-Farm Treatment

Corn 9.9 1.2 0.78 160 acres 0.000719 2,400 0.00188 270

Soybeans 0.46 0.000423 4,000 0.00110 460

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE, Eng. Controls. *Baseline for mixing/loading for commercial 

treatment of impregnated fertilizers is engineering controls in a closed system. 
Page 30 of 33

2 Based on registered labels. See Appendix B.

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 tons/day) × DAF (4 %) 

÷ BW (69 kg).

5 Dermal MOE = Dermal LOAEL (1.7 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 (0.143, 0.289, or 0.501 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

Table D.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet - Scenario requiring Gloves to Be Not of Concern. 

Exposure Scenario Crop or 

Target

Dermal Unit 

Exposure (μg/lb 

ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

(lb ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

Gloves Baseline Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 300)

Mixer/Loader

Mixing/Loading Liquids for 

On-Farm Treatment with

Impregnated Fertilizers

Soybeans 37.6 0.219 0.46 160 acres 0.00161 1,100 0.000201 1,400

Applicator

Applying Sprays via 

Groundboom Equipment 

Soybeans 16.1 0.34 0.46 200 acres 0.000858 2,000 0.000391 370

Wheat 0.34 0.000632 2,700 0.000289 490

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE, Eng. Controls.

2 Based on registered labels. See Appendix B.

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 (4 %) ÷ 

BW (69 kg).

5 Dermal MOE = Dermal LOAEL (1.7 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 (0.143, 0.289, or 0.501 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

Table D.3. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet - Scenarios Requiring Gloves and a PF5 Respirator to be Not of 

Concern. 

Exposure Scenario

Crop or 

Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

(lb ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

Gloves PF5 Respirator Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 300)

Mixer/Loader

Mixing/Loading Dry 

Flowables for Groundboom 

Application 

Sod 51.6 1.792 0.44 80 acres 0.00106 1,600 0.000789 370

Applicator
Page 31 of 33

Table D.3. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet - Scenarios Requiring Gloves and a PF5 Respirator to be Not of 

Concern. 

Exposure Scenario

Crop or 

Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

(lb ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

Gloves PF5 Respirator Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 300)

Applying Sprays via 

Groundboom Equipment Corn 16.1 0.068 0.78 200 acres 0.00146 1,200 0.000133 1,100

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE, Eng. Controls.

2 Based on registered labels. See Appendix B.

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 (4 %) ÷ 

BW (69 kg).

5 Dermal MOE = Dermal LOAEL (1.7 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 (0.143, 0.289, or 0.501 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

Table D.4. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet - Scenarios Requiring a PF5 Respirator to be Not of Concern. 

Exposure Scenario Crop or 

Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

(lb ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

Baseline PF5 Respirator Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 300)

Applicator

Applying Impregnated Dry 

Bulk Fertilizer - Commercial 

Treatment

Corn

9.9 0.24

0.78

320 acres

0.00143 1,200 0.000749 670

Soybeans 0.46 0.000846 2,000 0.000441 1.100

Applying Impregnated Dry 

Bulk Fertilizer - On-Farm 

Treatment

Corn 0.78 160 acres 0.000719 2,400 0.000375 1,300

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE, Eng. Controls.

2 Based on registered labels. See Appendix B.

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 (4 %) ÷ 

BW (69 kg).

5 Dermal MOE = Dermal LOAEL (1.7 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 (0.143, 0.289, or 0.501 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).
Page 32 of 33

Table D.5. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet - Scenarios requiring Double Layer and Gloves Not of 

Concern. 

Exposure Scenario Crop or 

Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

(lb ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

DL + G Baseline Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 300)

Mixer/Loader

Mixing/Loading Liquids for 

Groundboom Application Soybeans 29.1 0.219 0.46 200 acres 0.00155 1,100 0.000251 1,200

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE, Eng. Controls.

2 Based on registered labels. See Appendix B.

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 (4 %) ÷ 

BW (69 kg).

5 Dermal MOE = Dermal LOAEL (1.7 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 (0.143, 0.289, or 0.501 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

Table D.6. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet - Scenarios requiring Double Layer, Gloves, and a PF10 

Respirator to be Not of Concern. 

Exposure Scenario Crop or 

Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

(lb ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

DL + G PF10 Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 300)

Mixer/Loader

Mixing/Loading Dry 

Flowables for Groundboom 

Application

Wheat 41.2 0.896 0.34 200 acres 0.00162 1,000 0.000761 380

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE, Eng. Controls.

2 Based on registered labels. See Appendix B.

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 (4 %) ÷ 

BW (69 kg).

5 Dermal MOE = Dermal LOAEL (1.7 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 (0.143, 0.289, or 0.501 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).
Page 33 of 33

Table D.7. Occupational Handler Non-Cancer Exposure and Risk Estimates for Flufenacet - Scenarios requiring Engineering Controls to be Not of 

Concern. 

Exposure Scenario Crop or 

Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

(lb ai/A)

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation

EC EC Dose 

(mg/kg/day)4

MOE5 

(LOC = 1000)

Dose 

(mg/kg/day)6

MOE7 

(LOC = 300)

Mixer/Loader

Mixing/Loading Dry 

Flowables for On-Farm

Treatment with Impregnated 

Fertilizers

Corn

9.8 0.24

0.78

160 acres

0.00071 2,400 0.000375 1,300

Soybeans 0.46 0.00042 4,100 0.000221 2,300

Mixing/Loading Dry 

Flowables for Groundboom 

Application

Corn 0.78

200 acres

0.00089 1,900 0.000468 1,100

Soybeans 0.46 0.00052 3,300 0.000276 1,800

Mixing/Loading Liquids for 

On-Farm Treatment with 

Impregnated Fertilizers

Corn 0.78 160 acres 0.00062 2,700 0.000130 3,900

Mixing/Loading Liquids for 

Groundboom Application Corn 8.6 0.083 0.78 200 acres 0.00078 2,200 0.000161 3,100

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table”; Level of mitigation: Baseline, PPE, Eng. Controls.

2 Based on registered labels. See Appendix B.

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 (4 %) ÷ 

BW (69 kg).

5 Dermal MOE = Dermal LOAEL (1.7 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 (0.143, 0.289, or 0.501 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).