Date: 

Subject: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

March 24, 2016 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

Ethalfluralin. Occupational and Residential Exposure Assessment for 

Registration Review. 

PC Code: 113101 

Decision No.:...5135'76 

Petition No.: NA 

DP Barcode: 0432018 

Registration No.: NA 

Regulatory Action: Registration 

Review 

Risk Assessment Type: Occupational/Residential Exposure Assessment 

TXR No.: NA 

Case No.: 2260 

CAS No.: 5523-68-6 

MRID No.: NA 40 CFR: §180.416 

From: 

Through: 

To: 

Mon

Risk 

i

Assessment 

ca Hawkins, 

Branch 

Ph.D., M.P.H.

VI 

, Environmental Health Scientist }fLz ~ 

Health Effects Division (7509P) I 

Shalu 

Donna 

Sh

S. 

e

Davis

lat, Industrial 

, Branch 

Hy

Chief 

gienist 

~~ f\J. /./\ ,., . . _' .!_£),.... 

Risk Assessment Branch VI 1\:7)"1 ~ Q~\ 

Health Effects Division (7509P) 

and 

Jennifer R. Tyler, ExpoSAC Reviewer </)ft,/fc''-'-'Ve<-- r/~';J;l{(~~ Ivan Nieves, ExpoSAC Reviewer ayu~x.le_; ( d£/??:>:(!/.,tQ/ 7uL 

Exposure Science Advisory Committee (ExpoSAC) I HED 

Julie Van Alstine, M.P.H., Environmental Health Scientist/Risk Assessor 

Risk Assessment Branch VI 

Health Effects Division (7509P) 

and 

Kelly Ballard, Chemical Review Manager 

Tom Moriarty, Team Leader 

Neil Anderson, Branch Chief 

Risk Management and Implementation Branch l 

Page 1 of .30 
Pesticide Re-Evaluation Division (7508P) 

Introduction 

As part of Registration Review, the Pesticide Re-evaluation Division (PRO) of OPP has 

requested that the Health Effects Division (HED) conduct an occupational and residential 

exposure assessment, as needed, to estimate the risk to human health that will result from the 

currently registered uses of ethaltluralin. 

It is HED poli cy to use the best available data to assess exposure. Several sources of generi c 

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 1.1 ) and the Agricultural 

Handler Exposure Task Force (AHETF) database. Some of these data are proprietary, and 

subj ect to the data protection provisions of the Federal Insecticide, Fungicide, and Rodenticide 

Act (FIFRA). 

Note: This memorandum was reviewed by the Exposure Science Advisory Conm1ittee 

(ExpoSAC) on November 19, 2015. 

Page 2 of 3 0 
Page 3 of 30

Table of Contents

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

2.0 Risk Assessment Conclusions and Recommendations............................................................. 6

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

2.2 Label Recommendations from Occupational/Residential Assessment................................. 6

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

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

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

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates................................................ 11

7.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates..... 12

8.0 Occupational Exposure and Risk Estimates ........................................................................... 13

8.1 Occupational Handler Exposure/Risk Estimates................................................................ 13

8.2 Occupational Post-application Exposure/Risk Estimates................................................... 21

8.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates........................... 21

Appendix A. Summary of Occupational Non-cancer Algorithms............................................... 23

Appendix B. Summary of Occupational Cancer Algorithms ...................................................... 24

Appendix C. Occupational Handler Cancer Exposure and Risk Estimates................................. 25
Page 4 of 30

1.0 Executive Summary

HED has conducted an occupational and residential exposure assessment for Registration 

Review of the active ingredient (ai), ethalfluralin. Ethalfluralin is a preemergence herbicide used 

to control a variety of annual grasses and broadleaf weeds on agricultural sites.

Use/Exposure Profile

Ethalfluralin has multiple end-use products that are registered for use on various agricultural 

crops. Ethalfluralin is marketed as an emulsifiable concentrate and a granule. For most use 

sites, baseline attire (i.e., long-sleeved shirt, long pants, shoes and socks) and chemical-resistant 

gloves, chemical-resistant footwear plus socks, protective eyewear, chemical-resistant headgear 

for overhead exposure, and chemical-resistant apron when cleaning equipment, mixing, or 

loading are required. 

Based on the registered uses of ethalfluralin, it has been determined that the potential exposure 

scenarios that will need to be assessed include short- and intermediate-term occupational handler

exposures. Occupational post-application dermal exposure was not quantitatively assessed since 

there is no dermal hazard for ethalfluralin. 

Hazard Concerns

A dermal point of departure (POD) was not chosen for ethalfluralin because systemic toxicity 

was not seen in a 28-day dermal toxicity study in rats up to the limit dose (1,000 mg/kg/day), no 

evidence of increased susceptibility was observed, and a low dermal absorption value was 

reported; therefore, quantification of dermal risks is not required. For inhalation exposure, a twogeneration reproduction study in rats was selected to derive the inhalation route POD because a 

subchronic inhalation study was not available for ethalfluralin. A POD of 20 mg/kg/day (No 

Observed Adverse Effect Level) (NOAEL) based on increased liver weights (absolute and 

relative) in the F0-generation parents and F1 adults at 61 mg/kg/day ((Lowest Observed Adverse 

Effect Level) (LOAEL)) was selected for the short- and intermediate term inhalation POD. 

The level of concern (LOC) for non-cancer inhalation and incidental oral risk assessment is a 

margin of exposure (MOE) of 100 (i.e., an MOE < 100 is of concern). Ethalfluralin is 

considered “likely to be carcinogenic to humans” and an assessment of potential cancer risk was 

conducted using a linear low-dose approach. A Q1* of 8.9 x 10-2(mg/kg/day)-1 was used to 

estimate cancer risk following ethalfluralin exposure. Cancer dermal doses were adjusted for 

dermal absorption because the Q1* is based on an oral study (dermal absorption factor = 2.7 %).

Residential Exposure and Risk

There are no residential uses for ethalfluralin. Therefore, residential handler and post-application 

exposure and risk were not assessed. 
Page 5 of 30

Non-occupational Exposure and Risk

A quantitative spray drift assessment was conducted. Risk estimates from aerial and 

groundboom applications are not of concern from the field edge for all scenarios considered. 

Occupational Exposure and Risk

There were no non-cancer inhalation risk estimates of concern with baseline attire (i.e., longsleeved shirt, long pants, shoes and socks); all non-cancer short- and intermediate-term handler

inhalation risk estimates resulted in MOEs ranging from 460 to 160,000. All dermal and 

inhalation cancer risk estimates ranged from 6x10-7to 1x10-5at baseline attire plus the personal 

protective equipment (PPE) required on the label (gloves) for private handlers (assumed exposed 

for 10 days per year). All dermal and inhalation cancer risk estimates ranged from 2x10-6to 

2x10-4for commercial handlers (assumed exposed 30 days per year) at baseline attire plus the 

PPE required on the label (gloves). Note: Additional PPE requirements (i.e., chemical-resistant 

footwear plus socks, protective eyewear, chemical-resistant headgear for overhead exposure, and 

chemical-resistant apron) are listed on the label but are not reflected in the assessment.

There is potential for short- and intermediate-term occupational exposure during post-application 

activities, however, no short- or intermediate-term dermal POD selected for ethalfluralin, 

therefore a non-cancer dermal post-application assessment was not performed. An occupational 

post-application cancer assessment was not performed since the use directions does not indicate 

that ethalfluralin is applied directly to foliage. The use directions indicate that the product is to 

be applied to seeded crop prior to its emergence, or apply as a banded spray between rows after 

crop emergence or transplanting. 

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

inhalation exposure assessment was not performed for ethalfluralin 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 ethalfluralin. Although a quantitative 

occupational post-application inhalation exposure assessment was not performed, an 

occupational handler inhalation exposure assessment was performed. Handler exposure resulting 

from the application of pesticides outdoors is likely to result in higher exposure than postapplication exposure. Therefore, it is expected that these handler inhalation exposure estimates 

would be protective of most occupational post-application inhalation exposure scenarios. 

Restricted Entry Interval (REI)

Ethalfluralin has low acute toxicity by the oral, dermal, and inhalation routes of exposure 

(Toxicity Categories IV, IV and III, respectively). It is moderately irritating to the eye (Toxicity 

Category II) and produces moderate to severe skin irritation (category II). It is a dermal 

sensitizer. Therefore, the Worker Protection Standard (WPS) REI of 24 hours on the registered 

labels is adequate to protect agricultural workers from post-application exposures to ethalfluralin.
Page 6 of 30

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 and Recommendations

2.1 Summary of Risk Estimates

Occupational Handler Exposures and Risk Estimates

There were no non-cancer inhalation risk estimates of concern at baseline attire (i.e., longsleeved shirt, long pants, shoes and socks); all non-cancer inhalation short- and intermediateterm handler risk estimates resulted in MOEs ranging from 460 to 160,000. All dermal and 

inhalation cancer risk estimates ranged from 6x10-7to 1x10-5at baseline attire plus the PPE 

required on the label (gloves) for private handlers (assumed exposed for 10 days per year). All 

dermal and inhalation cancer risk estimates ranged from 2x10-6to 2x10-4for commercial 

handlers (assumed exposed 30 days per year) at baseline attire plus the PPE required on the label 

(gloves). 

Note: Additional PPE requirements (i.e., chemical-resistant footwear plus socks, protective 

eyewear, chemical-resistant headgear for overhead exposure, and chemical-resistant apron) listed 

on the registered labels are not reflected in the assessment.

2.2 Label Recommendations from Occupational/Residential Assessment 

None.

3.0 Hazard Characterization

Acute Toxicity

Ethalfluralin has low acute toxicity by the oral, dermal, and inhalation routes of exposure 

(Toxicity Categories IV, IV and III, respectively). It is moderately irritating to the eye (Toxicity 

Category II) and produces moderate to severe skin irritation (category II). It is a dermal 

sensitizer. Table 3.1 presents a summary of the acute toxicity information for ethalfluralin.

 

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 30

Toxicological PODs Used for Risk Assessment

Incidental Oral Endpoint: The two-generation reproduction study in rats (MRID 42300301) was 

selected for this endpoint. The NOAEL is 20 mg/kg/day and the LOAEL is 61 mg/kg/day based 

on increased liver weights (absolute and relative) in the F0-generation parents and F1-generation 

adults. This effect was also observed in the 90-day rat study at similar doses. The UF is 100 (10X 

for inter-species extrapolations, 10X for intra-species variations, and a 1X FQPA SF).

Dermal Endpoints: A 21-day dermal toxicity study in rabbits indicates no systemic toxicity at the 

limit dose of 1,000 mg/kg/day. No toxicity endpoints for short-term or intermediate-term dermal 

exposure were selected, and there is no short-term or intermediate-term dermal risk associated 

with the proposed or existing uses. Additionally, the dermal study is protective of the effects 

seen in the developmental rabbit study (absorptions, resorptions, skeletal variations) since the 

dermal equivalent dose (using the low DAF of 2.7%) for the oral study is well above the limit 

dose. 

Inhalation Endpoints: No inhalation toxicity study is available for ethalfluralin. The need for a 

subchronic inhalation study for ethalfluralin was discussed by the Hazard and Science Policy 

Council (HASPOC) (K. Rury, TXR # 0056533). The HASPOC concluded that based on a 

weight-of-evidence approach, considering all the available hazard and exposure information for 

ethalfluralin, a subchronic inhalation study is not needed at this time. Thus, the short-term and 

intermediate-term inhalation endpoint for worker exposures is derived from the two-generation 

reproduction study in rats (MRID 42300301). The NOAEL is 20 mg/kg/day and the LOAEL is 

61 mg/kg/day based on increased liver weights (absolute and relative) in the F0-generation 

parents and F1 adults. The UF is 100 (10X for inter-species extrapolations and a 10X for intraspecies variations). An assumption of 100% inhalation absorption is used for route-to-route 

extrapolation. The selected study is appropriate for the durations of exposure and is protective of 

the developing fetus of potentially pregnant female workers. 

Cancer: Ethalfluralin has been classified as a possible human carcinogen (Group C) by the 

Carcinogenicity Peer Review Committee (CPRC; R. Landolt and E. Rinde, 9/14/1994). The 

decision was based on positive genotoxicity assays (two positive Salmonella assays and a 

Table 3.1 Acute Toxicity Profile for Ethalfluralin

Guideline No. Study Type MRID No. Results Toxicity Category

870.1100 Acute oral toxicity rats 00135189 LD50 >5000 mg/kg/ IV

870.1200 Acute dermal toxicity 

rabbit 00135189 LD50 >5000 mg/kg/ IV

870.1300 Acute inhalation toxicity 

rats 00135189 LC50> 0.94 mg/L III

870.2400 Acute eye irritation rabbits 00135189 Moderate II

870.2500 Acute dermal irritation 

rabbits 41613909 Moderate to severe II

870.2600 Dermal sensitization 

guinea pigs 00094788 Sensitizer --
Page 8 of 30

positive assay for chromosomal aberrations) and findings from a 2-year chronic carcinogenicity 

study in rats (showing an increased incidence of mammary gland fibroadenomas and combined 

adenomas/fibroadenomas in female rats). The CPRC recommended using the Q1

*

approach for 

risk assessment. The Q1

*

is 8.9 x 10-2(mg/kg/day)-1. 

A summary of the toxicological doses and endpoints for use in this occupational and residential 

risk assessment are provided in Table 3.2.

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). LOC = level of concern. IA = inhalation 

absorption factor.

Table 3.2 Summary of Toxicological Doses and Endpoints for Ethalfluralin for Use in 

Occupational and Non-Occupational Human Health Risk Assessments

Exposure/

Scenario

Point of 

Departure

Uncertainty

Factors

Level of Concern for 

Risk Assessment

Study and Toxicological 

Effects

Dermal, 

Short-term (1 to 30 

days) and 

Intermediate-term 

(1-6 months)

Dermal risks are not of concern because no systemic effects were observed up to the limit 

dose (1000 mg/kg) in a dermal study.

Inhalation, 

Short-term (1 to 30 

days) and

Intermediate-term 

(1-6 months)

(oral)

NOAEL = 20 

mg/kg/day

UFH=10X

UFA=10X

IA = 100%

LOC = 100

Rat Two-generation 

Reproduction Toxicity Study

MRID: 42300301

LOAEL = 61 mg/kg/day based 

on increased liver weights 

(absolute and relative) in F0-

generation and F1-generation 

adults.

Incidental Oral 

Short-Term (1-30 

days) and 

Intermediate-term 

(1-6 months)

NOAEL = 20

mg/kg/day

UFA = 10x

UFH =10x

FQPA SF= 

1X

LOC = 100 Rat Two-generation 

Reproduction Toxicity Study

MRID: 42300301

LOAEL = 61 mg/kg/day based 

on increased liver weights 

(absolute and relative) in F0-

generation and F1-generation 

adults.

Cancer (oral, 

dermal, inhalation)

Ethalfluralin has been classified as a possible human 

carcinogen (Group C) based on increased mammary 

gland fibro-adenomas & combined adenomas/fibroadenomas in female rats. Q* = 8.9 x 10-2

(mg/kg/day)-1. 

[For the dermal route, a dermal absorption factor of 

2.7% was used for assessing cancer aggregate risk]

Rat, 2-year 

chronic/carcinogenicity study

MRID: 00094776, 92062013
Page 9 of 30

Absorption

A dermal absorption factor of 2.7% was used for the cancer assessment. Since no inhalation 

absorption data are available, toxicity by the inhalation route is considered to be equivalent to the 

estimated toxicity by the oral route of exposure.

Body Weight

The standard body weight for the general population (80 kg) was used for the non-cancer 

occupational handler assessment since the endpoints selected were not developmental and/or 

fetal effects. Since the inhalation PODs for cancer are based on developmental and/or fetal 

effects, the body weight appropriate for inhalation cancer assessments is 69 kg. A body weight 

of 11 kg was used to assess exposure to children (1 to < 2 years old) from spray drift.

4.0 Use Profile 

Table 4.1 provides a summary of the highest application rate of the registered uses for 

ethalfluralin. 

Table 3.3. Summary of Directions for Use of Ethalfluralin.

Type of 

Application

Registered 

Formulations

Max. 

Applic. 

Rate

REI Use Directions and Limitations

Dry Beans, Sunflower

Aerial, Ground,

Chemigation Emulsifiable 

Concentrate

1.7 lb 

ai/A 

24 hours

Apply Sonalan HFP through properly equipped 

chemigation systems to dry beans (does not include 

soybean) and sunflower. Do not apply this product 

through any type of irrigation system to other labeled 

crops, unless otherwise specified by a Dow 

AgroSciences product bulletin or supplemental label. Dry Bulk Fertilizer1 17 lb 

ai/ton

Dry Peas

Aerial, Ground Emulsifiable 

Concentrate

0.75 lb 

ai/A 24 hours

Do not apply this product through any type of 

irrigation system to other labeled crops, unless 

otherwise specified by a Dow AgroSciences product 

bulletin or supplemental label.

Canola

Aerial, Ground Emulsifiable 

Concentrate

0.94 lb 

ai/A 24 hours

Do not apply this product through any type of 

irrigation system to other labeled crops, unless 

otherwise specified by a Dow AgroSciences product 

bulletin or supplemental label.

Safflower, Peanuts

Aerial, Ground Emulsifiable 

Concentrate

1.13 lb 

ai/A 24 hours

Do not apply this product through any type of 

irrigation system to other labeled crops, unless 

otherwise specified by a Dow AgroSciences product 

bulletin or supplemental label.

Potatoes

Aerial, Ground Emulsifiable 

Concentrate

1.01 lb 

ai/A 24 hours

Do not apply this product through any type of 

irrigation system to other labeled crops, unless 

otherwise specified by a Dow AgroSciences product 

bulletin or supplemental label.

Soybean
Page 10 of 30

Table 3.3. Summary of Directions for Use of Ethalfluralin.

Type of 

Application

Registered 

Formulations

Max. 

Applic. 

Rate

REI Use Directions and Limitations

Aerial, Ground

Emulsifiable 

Concentrate

1.3 lb 

ai/A

24 

hours.

Apply Sonalan HFP through properly equipped 

chemigation systems to dry beans (does not include 

soybean) and sunflower. Do not apply this product 

through any type of irrigation system to other labeled 

crops, unless otherwise specified by a Dow 

AgroSciences product bulletin or supplemental label.

Dry Bulk Fertilizer1 13 lb 

ai/ton

Cucumbers, Pumpkins, Summer Squash, Winter Squash, Watermelons

Aerial, Ground

Emulsifiable 

Concentrate

1.7 lb 

ai/A 24 hours Do not apply to any area not specified on the label.

Alfalfa

Ground, 

Chemigation

Emulsifiable 

Concentrate

1.69 lb 

ai/A 24 hours

SLN (OR-940037; NV-950001; ID950020; MT010002; WY-030005; WA-940018). Do not make 

more than one application per crop. Do not apply the 

product to soils that are wet, cloddy, or subject to 

prolonged periods of flooding. Do not apply to 

seedling alfalfa (up to 6 true leaf stage). 

Clover

Ground Emulsifiable 

Concentrate

1.5 lb 

ai/A 24 hours

SLN (WY-030005). Do not apply the product to soils 

that are wet, cloddy, or subject to prolonged periods 

of flooding. Do not apply to seedling clover (up to 6 

true leaf stage).

Dill

Ground Emulsifiable 

Concentrate

1.125

lb ai/A 24 hours

34704-610 SLN (OR-120002; WA-090013) Do not 

graze or forage crop grown in treated soil or cut for 

hay or silage.

Do not apply CURBIT® to soils which are wet, 

cloddy, or subject to prolonged periods of flooding 

because poor weed control or crop injury may result. 

Do not apply to any area not specified on the label.

Do not incorporate CURBIT prior to planting as crop 

loss will occur. Do not use CURBIT under or over 

row covers, hot caps, plastic mulches, or other plant 

covers as severe crop injury will occur. Do not make 

broadcast application to transplants. Do not plant in a 

furrow. Do not spray over plastic mulch

Sunflower, Dry Beans

Aerial, Ground Granule 1.7 lb 

ai/A 24 hours Apply only in areas and to crops specified on this label.

Dry Peas

Aerial, Ground Granule 0.75 lb 

ai/A

24 

hours.

Apply only in areas and to crops specified on this 

label.

Canola

Aerial, Ground Granule 0.95 lb 

ai/A

24 

hours.

Apply only in areas and to crops specified on this 

label.

Safflower, Peanuts

Aerial, Ground Granule 1.15 lb 

ai/A

24 

hours.

Apply only in areas and to crops specified on this 

label.

Soybeans

Aerial, Ground Granule 1.3 lb 

ai/A

24 

hours.

Apply only in areas and to crops specified on this 

label.
Page 11 of 30

1. To calculate the dry bulk fertilizer rate: Application Rate (lb ai/A) × (1 A/200 lb fertilizer) × (2000 lb fertilizer/1 ton 

fertilizer) = lb ai/ton fertilizer.

5.0 Residential Exposure and Risk Estimates

There are no residential uses proposed for ethalfluralin. Therefore, residential handler and postapplication exposure/risk were not assessed. 

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates

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 include 

assessing 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 exposure scenario. 

Aside from the predicted residues available for transfer, the routes of exposure and assessment 

methodology is 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 flurprimidol. 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. 

Exposures were considered for 50 feet wide lawns where the nearest side of the property was 

directly adjoining the treated field (at field edge) and at varied distances up to 300 feet 

downwind of a treated field. 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 for situations where specific label guidance for 

application parameters is not available.2 AgDrift® is appropriate for use only when applications 

are made by aircraft, airblast 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 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. 

In all cases, each scenario is to be evaluated unless it is not plausible based on the anticipated use 

 

2http://www.agdrift.com/ 
Page 12 of 30

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

(e.g., aerial applications are not allowed). The section below provides the screening level drift 

related risk estimates. These drift estimates represent plausible options based on the available 

pesticide labels. 

Risk Estimates From Lawn Deposition Adjacent to Applications

The spray drift risk estimates are based on an estimated deposited residue concentration as a 

result of the screening level agricultural application scenarios. Ethalfluralin is used to control a

variety of annual grasses and broadleaf weeds on various agricultural sites. The spray drift 

assessment was conducted using the highest registered application rate of 1.7 lb ai/A for use on 

sunflower and dry beans cucumbers, pumpkins, summer squash, winter squash, and 

watermelons. 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. 

 Aerial applications are based on the use of AgDrift® Tier 1 aerial option for a fine-tomedium spray type and a series of other parameters, which will be described in more 

detail below (e.g., wind vector assumed to be 10 mph in a downwind direction for entire 

application/drift event).

There are no short- or intermediate-term dermal PODs. Only incidental oral risk estimates were 

evaluated. The total applicable LOC is 100, so MOEs <100 would be of concern. Children (1 to 

<2 years old) incidental oral risk estimates from exposure to ethalfluralin related to spray drift 

result in no risks of concern at the field edge for groundboom applications (Table 6.1). 

Table 6.1. Children (1 to < 2 years old) Incidental Oral Risk Estimates (MOEs) Related to 

Spray Drift Exposure for Ethalfluralin.

1

Crop/Rate 

Group

Spray Type/ Nozzle 

Configuration 

Application 

Rate (lb 

ai/A)

Estimated 

or 

Adjusted 

TTRt

(ug/cm2)

At Edge 

HtM MOE 

Sunflower, Dry Beans, Cucumbers, Pumpkins, Summer Squash, Winter Squash, Watermelons

Aerial Fine to Medium

1.7 0.188955

3,000

Groundboom High Boom Very fine to 

Fine 4,100

1 The spray drift assessment was conducted using the highest registered application rate of 1.7 lb ai/A for use on 

sunflower, dry beans, cucumbers, pumpkins, summer squash, winter squash, and watermelons. Therefore, the 

highest application rate is protective of all registered ethalfluralin uses.

7.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates

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 
Page 13 of 30

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

ethalfluralin.

8.0 Occupational Exposure and Risk Estimates

8.1 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 

following scenarios: 

 Mixing/Loading granules for aerial application,

 Mixing/Loading granules for tractor application,

 Mixing/Loading liquids for commercial treatment with impregnated fertilizers,

 Mixing/Loading liquids for on-farm treatment with impregnated fertilizers,

 Mixing/Loading liquids for aerial application,

 Mixing/Loading liquids for chemigation and groundboom application; 

 Applying sprays for aerial application,

 Applying sprays for groundboom application,

 Applying ethalfluralin in commercial impregnated dry bulk fertilizers,

 Applying ethalfluralin in on-farm impregnated dry bulk fertilizers, 

 Applying granules for aerial application, 

 Applying granules for tractor application

 Flagging for aerial application for liquids, and

 Flagging for aerial application for granules.

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: Refer to the currently registered use patterns at the maximum application rates 

in Table 4.1.
Page 14 of 30

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, 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.

For the dry bulk fertilizer scenarios, HED assumed a closed mixing/loading scenario for 

commercial impregnation of dry bulk fertilizer, and an open mixing/loading scenario for growerowned equipment impregnation of dry bulk fertilizer. For all applications of dry bulk fertilizer, 

HED assumed the use of an open-cab spreader.

Area Treated or Amount Handled: The area treated or amount handled is based on HED 

ExpoSAC Policy No. 9.1. Refer to Table 8.1.1 for these assumptions for each scenario.

Since the exposure and risk will be less for the typical field crops (cucumber, pumpkins, summer 

squash, winter squash, and watermelons) than the high acreage field crops (sunflower and dry 

beans) the high acreage field crop assessment covers the potential exposure and risk from 

treating the typical field crops with ethalfluralin. Table 8.1.1. provides the worst-case scenarios 

for the registered uses for ethalfluralin. 

HED does not have data regarding the mixing/loading or the application of ethalfluralinimpregnated dry bulk fertilizer. The mixing/loading processing rate for commercial 

impregnation of dry bulk fertilizer has been estimated to be 960 tons of fertilizer processed per 8 

hour day based on information supplied by a registrant concerning the chemical alachlor (as 

referenced in its reregistration eligibility document (RED) document5). Mixing/loading for onfarm impregnation of dry bulk fertilizer was then assessed using an estimate of 160 acres/day. 

Application of dry bulk fertilizer was assessed assuming application to up to 320 acres/day for 

commercial equipment and 160 acres/day for grower-owned equipment. 

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). 

 

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

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

5 http://www.epa.gov/oppsrrd1/REDs/0063.pdf
Page 15 of 30

For ethalfluralin, based on the currently registered uses, short- and intermediate-term exposure is 

expected for occupational non-cancer and cancer handlers. The short- and intermediate-term 

endpoints and PODs are the same for the inhalation route of exposure and, therefore, only shortterm handler exposures were estimated and are considered protective for intermediate-term 

exposure and risk. Long-term exposures are not expected.

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). For most use sites, baseline attire (i.e., long-sleeved shirt, long pants, 

shoes and socks) and chemical-resistant gloves, chemical-resistant footwear plus socks, 

protective eyewear, chemical-resistant headgear for overhead exposure, and chemical-resistant 

apron when cleaning equipment, mixing, or loading are required.

Days per Year of Exposure: To assess cancer risk, it is assumed that private growers would be 

exposed 10 days per year and commercial applicators would be exposed 30 days per year. The 

term “private grower” means that the grower or one of the workers would apply the pesticides to 

land owned or operated by the grower. Commercial applicators means the applicators are 

completing multiple applications for multiple clients.

Years per Lifetime of Exposure: It is assumed that handlers would be exposed for 35 years out of 

a 78 year lifespan.

Lifetime Expectancy: Life expectancy values are from the Exposure Factors Handbook 2011 

Edition Table 18-1 (U.S. EPA, 2011). The table shows that the overall life expectancy is 78 

years based on life expectancy data from 2007. In 2007, the average life expectancy for males 

was 75 years and 80 years for females. Based on the available data, the recommended value for 

use in cancer risk assessments is 78 years. 

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 no inhalation risk estimates of concern at baseline attire (no personal protective

equipment; PPE); all non-cancer short- and intermediate-term handler risk estimates (inhalation 

only) resulted in MOEs ranging from 460 to 160,000. Table 8.1.1. provides the worst-case 

scenarios for the registered uses for ethalfluralin. Therefore, all other application rates/inputs 

would result in risk estimates below those currently presented in Table 8.1.1.

The Agency matches quantitative occupational exposure assessment with appropriate 

characterization of exposure potential. While HED presents quantitative risk estimates for human 
Page 16 of 30

flaggers where appropriate, agricultural aviation has changed dramatically over the past two 

decades. According the 2012 National Agricultural Aviation Association (NAAA) survey of 

their membership, the use of GPS for swath guidance in agricultural aviation has grown steadily 

from the mid 1990’s. Over the same time period, the use of human flaggers for aerial pesticide 

applications has decreased steadily from ~15% in the late 1990’s to only 1% in the most recent 

(2012) NAAA survey. The Agency will continue to monitor all available information sources to 

best assess and characterize the exposure potential for human flaggers in agricultural aerial 

applications.

HED has no data to assess exposures to pilots using open cockpits. The only data available is for 

exposure to pilots in enclosed cockpits. Therefore, risks to pilots are assessed using the 

engineering control (enclosed cockpits) and baseline attire (long-sleeve shirt, long pants, shoes, 

and socks); per the Agency’s Worker Protection Standard stipulations for engineering controls, 

pilots are not required to wear protective gloves for the duration of the application. With this 

level of protection, there are no risk estimates of concern for applicators.

Table 8.1.1. Occupational Handler Non-Cancer Short- and Intermediate-Term Handler Exposure and Risk 

Estimates for Ethalfluralin.

Exposure Scenario Crop or Target1

Baseline 

Inhalation 

Unit 

Exposure2

μg/lb ai

(unless 

otherwise 

indicated)

Maximum

Application 

Rate3

Area 

Treated or 

Amount 

Handled 

Daily4

Baseline Inhalation

Dose5

mg/kg/day

MOE6

LOC = 100

Mixer/Loader

M/L Granules for Aerial 

Application

High-Acreage Field 

Crops 1.7

1.7 lb ai/A 1,200 

acres

0.0434 460

M/L Granules for Tractor-Drawn 

Spreader Application

High-Acreage Field 

Crops 1.7 lb ai/A 200 acres 0.00723 2,800

M/L Liquids for Commercial 

Treatment with Impregnated 

Fertilizers

Sunflower, Dry Beans 0.083

(EC) 17 lb ai/ton 960 tons 0.0169 1,200

M/L Liquids for On-Farm 

Treatment with Impregnated 

Fertilizers

Sunflower, Dry Beans 0.219 1.7 lb ai/A 160 acres 0.000745 27,000

M/L Liquids for Aerial Application High-Acreage Field 

Crops

0.219 1.7 lb ai/A

1,200 

acres

0.00559 3,600

M /L Liquids for Chemigation 

Application Sunflower, Dry Beans 350 acres 0.00163 12,000

M /L Liquids for Groundboom 

Application

High-Acreage Field 

Crops 200 acres 0.000931 21,000

Applicator

Applying Sprays for Aerial 

Application

High-Acreage Field 

Crops

0.0049

(EC) 1.7 lb ai/A 1,200 acres

0.000125 160,000

Applying Sprays for Groundboom 

Application

High-Acreage Field 

Crops 0.34

1.7 lb ai/A

200 acres 0.00145 14,000

Applying Impregnated Dry Bulk 

Fertilizer - Commercial Treatment Sunflower, Dry Beans

1.2

320 acres 0.00816 2,500

Applying Impregnated Dry Bulk

Fertilizer - On-Farm Treatment Sunflower, Dry Beans 160 acres 0.00408 4,900

Applying Granules for Aerial 

Application

(Engineering Controls)

High-Acreage Field 

Crops

1.3

(EC) 1.7 lb ai/A 1,200 acres

0.0331 600
Page 17 of 30

Table 8.1.1. Occupational Handler Non-Cancer Short- and Intermediate-Term Handler Exposure and Risk 

Estimates for Ethalfluralin.

Exposure Scenario Crop or Target1

Baseline 

Inhalation 

Unit 

Exposure2

μg/lb ai

(unless 

otherwise 

indicated)

Maximum

Application 

Rate3

Area 

Treated or 

Amount 

Handled 

Daily4

Baseline Inhalation

Dose5

mg/kg/day

MOE6

LOC = 100

Applying Granules for TractorDrawn Spreader Application Sunflower, Dry Beans 1.2 1.7 lb ai/A 200 acres 0.0051 3,900

Flagger

Flagger for Aerial Application for 

Liquids High-Acreage Field 

Crops

0.35

1.7 lb ai/A 350 acres

0.0026 7,700

Flagger for Aerial Application for 

Granules 0.15 0.00112 18,000

1 “High Acreage Field Crops” include Sunflower and Dry Beans. Note: All other single application rates would result in risk estimates below 

those currently presented in Table 8.1.1.

2 “Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (September 2015); Level of mitigation = Baseline 

except for aerial applicator which includes engineering controls.

3 Based on the registered labels (See Table 4.1).

4 Exposure Science Advisory Council Policy #9.1.

5 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 Daily (A or gal/day) ÷ BW (80kg).

6 Short- and Intermediate-term Inhalation MOE = Inhalation NOAEL (20 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

Occupational Handler Cancer Exposure and Risk Equations

Although a non-cancer dermal risk assessment was not performed due to the lack of an adverse 

effect in the non-cancer dermal study, a dermal cancer exposure and risk assessment was 

performed because dermal exposure does contribute to the overall cancer risk for ethalfluralin. 

Cancer risk estimates were calculated using a linear low-dose extrapolation approach in which a 

Lifetime Average Daily Dose (LADD) is first calculated and then compared with a Q1* that has 

been calculated for ethalfluralin based on dose response data in the appropriate toxicology study 

(Q1* = 0.089 (mg/kg/day)-1). Absorbed average daily dose (ADD) levels were used as the basis 

for calculating the LADD values. Dermal and inhalation ADD values were first added together 

to obtain combined ADD values. LADD values were then calculated and compared to the Q1* to 

obtain cancer risk estimates. The algorithms used to estimate the LADD and cancer risk for 

occupational handlers can be found in Appendix B.

Summary of Occupational Handler Cancer Exposure and Risk Estimates

All dermal and inhalation cancer risk estimates ranged from 6x10-7to 1x10-5at baseline attire 

plus the PPE required on the label (gloves) and with engineering controls for private handlers 

(assumed exposed for 10 days per year) and 2x10-6to 2x10-4at baseline attire plus the PPE 

required on the label (gloves) and with engineering controls for commercial handlers (assumed 

exposed for 30 days per year). See Table 8.1.2 below. Occupational handler cancer exposure 

and risk estimates with varying mitigation measure including a PF5 respirator, PF10 respirator, 

and with engineering controls are shown in Appendix C (Tables C.1., C.2., and C.3.). Note: 

Additional PPE requirements (i.e., chemical-resistant footwear plus socks, protective eyewear, 
Page 18 of 30

chemical-resistant headgear for overhead exposure, and chemical-resistant apron) are listed on 

the label that is not reflected in the assessment.
Page 19 of 30

Table 8.1.2. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Label-Required PPE. 

Exposure Scenario Crop/Target1

Private Handler Commercial Handler

LADD (mg/kg/day)

Total LADD4 Cancer Risk 

Estimate5

LADD (mg/kg/day)

Total LADD4 Cancer Risk 

Estimate5 Dermal2

Inhalation3

(No R

unless otherwise 

indicated)

Dermal2

Inhalation3

(No R

unless otherwise 

indicated)

M/L Granules for 

Aerial Application High-Acreage Field Crops 0.0000679 0.000618 0.000686 6E-05 0.000204 0.00186 0.00206 2E-04

M/L Granules for 

Tractor-Drawn 

Spreader 

Application

High-Acreage Field Crops 0.0000113 0.000103 0.000114 1E-05 0.0000339 0.000309 0.000343 3E-05

M/L Liquids for 

Commercial 

Treatment with 

Impregnated 

Fertilizers

(EC)

Sunflower, Dry Beans 0.000674 0.000241

(EC) 0.000915 8E-05 0.00202 0.000723(EC) 0.00274 2E-04

M/L Liquids for 

On-Farm Treatment 

with Impregnated 

Fertilizers

Sunflower, Dry Beans 0.0000491 0.0000106 0.0000596 5E-06 0.000147 0.0000319 0.000179 2E-05

M/L Liquids for 

Aerial Application Typical Field Crops 0.000108 0.0000231 0.000132 1E-05 0.000323 0.0000693 0.000395 4E-05

M/L Liquids for 

Aerial Application High-Acreage Field Crops 0.000369 0.0000797 0.000449 4E-05 0.00111 0.000239 0.00135 1E-04

M /L Liquids for 

Chemigation 

Application

Typical Field Crops 0.000108 0.0000231 0.000132 1E-05 0.000323 0.0000693 0.000395 4E-05

M /L Liquids for 

Chemigation 

Application

Sunflower, Dry Beans 0.000108 0.0000231 0.000132 1E-05 0.000323 0.0000693 0.000395 4E-05

M /L Liquids for 

Groundboom 

Application

Typical Field Crops 0.0000246 0.00000531 0.0000299 3E-06 0.0000738 0.0000159 0.0000896 8E-06

M /L Liquids for 

Groundboom 

Application

High-Acreage Field Crops 0.0000616 0.0000133 0.0000749 7E-06 0.000185 0.0000398 0.000225 2E-05

Applicator

Applying Sprays for 

Aerial Application

(Engineering 

Controls) 

Typical Field Crops 0.00000596 0.00000052

(EC) 0.00000648 6E-07 0.0000179 0.00000156(EC) 0.0000194 2E-06

Applying Sprays for 

Aerial Application

(Engineering 

Controls)

High-Acreage Field Crops 0.0000204 0.00000178

(EC) 0.0000223 2E-06 0.0000612 0.00000535(EC) 0.0000668 6E-06
Page 20 of 30

Table 8.1.2. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Label-Required PPE. 

Exposure Scenario Crop/Target1

Private Handler Commercial Handler

LADD (mg/kg/day)

Total LADD4 Cancer Risk 

Estimate5

LADD (mg/kg/day)

Total LADD4 Cancer Risk 

Estimate5 Dermal2

Inhalation3

(No R

unless otherwise 

indicated)

Dermal2

Inhalation3

(No R

unless otherwise 

indicated)

Applying Sprays for 

Groundboom 

Application

Typical Field Crops 0.0000105 0.00000824 0.0000188 2E-06 0.0000316 0.0000247 0.0000564 5E-06

Applying Sprays for 

Groundboom 

Application

High-Acreage Field Crops 0.0000263 0.0000207 0.000047 4E-06 0.0000789 0.000062 0.000141 1E-05

Applying 

Impregnated Dry 

Bulk Fertilizer -

Commercial 

Treatment

Sunflower, Dry Beans 0.0000188 0.000116 0.000135 1E-05 0.0000564 0.000349 0.000406 4E-05

Applying 

Impregnated Dry 

Bulk Fertilizer - OnFarm Treatment

Sunflower, Dry Beans 0.00000943 0.000058 0.0000675 6E-06 0.0000283 0.000174 0.000202 2E-05

Applying Granules 

for Aerial

Application

(EC)

High-Acreage Field Crops 0.0000167 0.000472

(EC) 0.000489 4E-05 0.0000502 0.00142(EC) 0.00147 1E-04

Applying Granules 

for Tractor-Drawn 

Spreader 

Application

Sunflower, Dry Beans 0.0000118 0.0000727 0.0000845 8E-06 0.0000354 0.000218 0.000253 2E-05

Flagger for Aerial 

Application for 

Liquids

Typical Field Crops 0.0000343 0.000037 0.0000713 6E-06 0.000103 0.000111 0.000214 2E-05

Flagger for Aerial 

Application for 

Liquids

High-Acreage Field Crops 0.0000343 0.000037 0.0000713 6E-06 0.000103 0.000111 0.000214 2E-05

Flagger for Aerial 

Application for 

Granules

High-Acreage Field Crops 0.00000779 0.0000159 0.0000236 2E-06 0.0000234 0.0000476 0.0000708 6E-06

1 “High Acreage Field Crops” include Sunflower and Dry Beans. “Typical Field Crops” include Cucumbers, Pumpkins, Summer Squash, Winter Squash, and Watermelons. 

2 Dermal LADD (mg/kg/day) = Dermal dose (mg/kg/day) × [Days per year of exposure (days/yr) ÷ 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

3 Inhalation LADD (mg/kg/day) = Inhalation Dose (mg/kg/day) × [Days per year of exposure (days/yr) / 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

Engineering Controls = EC

4 Total LADD (mg/kg/day) = Dermal LADD (mg/kg/day) + Inhalation LADD (mg/kg/day).

5 Cancer risk estimates = Total LADD × Q1

*

, where Q1

* = 0.089 (mg/kg/day)-
Page 21 of 30

8.2 Occupational Post-application Exposure/Risk Estimates

Occupational post-application dermal exposure was not assessed for ethalfluralin because there 

is no identified systemic dermal hazard. An occupational post-application cancer assessment 

was not performed since the use directions does not indicate that ethalfluralin is applied directly 

to foliage. The use directions indicate that the product is to be applied to seeded crop prior to its 

emergence, or apply as a banded spray between rows after crop emergence or transplanting. 

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

exposure assessment was not performed for ethalfluralin at this time. However, an inhalation 

exposure assessment was performed for occupational handlers and this assessment resulted in 

risk estimates that did not exceed HED’s level of concern at baseline inhalation PPE. Since 

handler exposure resulting from application of pesticides outdoors is likely to result in higher 

exposure than post-application exposure; these handler inhalation exposure estimates would be 

protective of most occupational post-application inhalation exposure scenarios. 

Dislodgeable Foliar Residue (DFR): In accordance with the updated Part 158 data requirements 

(2007), one or more DFR studies are required when a pesticide has residential or occupational 

uses that could result in post-application dermal exposure. Since there is no hazard via the 

dermal route of exposure, a non-cancer dermal post-application risk assessment was not 

performed for ethalfluralin. Therefore, DFR studies are not needed for ethalfluralin at this time. 

If the PODs change, the need for DFR studies may be reevaluated in the future to refine the postapplication assessment.

8.2.1 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 

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 ethalfluralin.

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.
Page 22 of 30

Restricted Entry Interval

Ethalfluralin is classified as Toxicity Category IV via the dermal route and Toxicity Category II 

for skin irritation potential. It is a skin sensitizer. Under 40 CFR 156.208 (c) (2), ai’s classified 

as Acute II for acute dermal, eye irritation and primary skin irritation are assigned a 24-hour REI. 

Therefore, the [156 subpart K] Worker Protection Statement interim REI of 24 hours is adequate 

to protect agricultural workers from post-application exposures to ethalfluralin. HED would 

recommend a REI of 24 hours. This is the REI listed on the currently registered labels, and is 

considered protective of post-application exposure. 
Page 23 of 30

Appendix A. Summary of Occupational 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 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 24 of 30

Appendix B. Summary of Occupational Cancer Algorithms

After the development of the ADD values, the next step required to calculate carcinogenic risk 

estimates is to amortize these values over the anticipated lifetime, which results in the LADD. 

LADD values are calculated using the following equation:

LADD = ADD * 

Days per Year of Exposure

365 Days per Year * 

Years per Lifetime of Exposure

Lifetime Expectancy

where:

LADD = absorbed dose over a lifetime (mg ai/kg/day),

ADD = average daily dose absorbed in a given scenario (mg 

ai/kg/day),

Days per Year of Exposure = annual frequency of an application by an individual 

(days/year),

Years per Lifetime of Exposure = amount of a lifetime that an individual would be 

expected to use pesticides (years), and

Lifetime Expectancy = average life expectancy of an individual (years).

Cancer risk estimate calculations are completed by comparing the LADD values calculated 

above to the Q1* for the chemical. Cancer risk estimates are calculated using the following 

equation:

Total Cancer Risk Estimate = (Dermal LADD + Inhalation LADD) * Q1*

where:

Cancer Risk Estimate = probability of incidence of cancer cases over a lifetime (unitless),

Dermal LADD = absorbed dose from dermal exposure over a lifetime (mg ai/kg/day),

Inhalation LADD = absorbed dose from inhalation exposure over a lifetime (mg

ai/kg/day), and

Q1* = quantitative dose response factor used for linear, low-dose response 

cancer risk estimate calculations (mg/kg/day)-1.
Page 25 of 30

Appendix C. Occupational Handler Cancer Exposure and Risk Estimates 

Occupational handler cancer exposure and risk estimates with varying mitigation measures including a PF5 respirator, PF10 respirator, 

and with engineering controls are shown in Tables C.1., C.2., and C.3. below. 

Note: Additional PPE requirements (i.e., chemical-resistant footwear plus socks, protective eyewear, chemical-resistant headgear for 

overhead exposure, and chemical-resistant apron) are listed on the label that is not reflected in the assessment.

Table C.1. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Additional PPE (PF5 Respirator, Double Layer Gloves). 

Exposure Scenario Crop or 

Target

Private Handler Commercial Handler

LADD (mg/kg/day) Total 

LADD3

(SL/G + 

PF5R)

Total

LADD3

(DL/G 

+PF5R)

Cancer Risk 

Estimate4

(SL/G +PF5R)

Cancer Risk 

Estimate

(DL/G+PF5

R)

LADD (mg/kg/day)

Total LADD3

(SL/G+PF5R)

Total 

LADD3

(DL/G+PF

5R)

Cancer 

Risk 

Estimate4

(SL/G+PF

5R)

Cancer 

Risk 

Estimate4

(DL/G+PF

5R)

Dermal

(SL/G)1

Dermal

(DL/G)

Inhalation2

(PF5R) Dermal

(SL/G)1

Dermal

(DL/G)1

Inhalation

(PF5R)2

M/L Granules for 

Aerial Application

HighAcreage 

Field Crops

0.0000679 0.0000334 0.000124 0.000192 0.000157 2E-05 1E-05 0.000204 0.0001 0.000372 0.000575 0.000472 5E-05 4E-05

M/L Granules for 

Tractor-Drawn 

Spreader 

Application

HighAcreage 

Field Crops

0.0000113 0.00000558 0.0000207 0.000032 0.0000262 3E-06 2E-06 0.0000339 0.0000167 0.000062 0.0000959 0.0000786 9E-06 7E-06

M/L Liquids for 

Commercial 

Treatment with 

Impregnated 

Fertilizers

Sunflower, 

Dry Beans ND ND ND ND ND ND ND ND ND ND ND ND ND ND

M/L Liquids for 

On-Farm Treatment 

with Impregnated 

Fertilizers

Sunflower, 

Dry Beans 0.0000491 0.0000381 0.00000211 0.0000511 0.0000402 5E-06 4E-06 0.000147 0.000114 0.00000634 0.000153 0.000121 1E-05 1E-05

M/L Liquids for 

Aerial Application

Typical Field 

Crops 0.000108 0.0000832 0.00000465 0.000112 0.0000879 1E-05 8E-06 0.000323 0.00025 0.0000139 0.000337 0.000264 3E-05 2E-05

M/L Liquids for 

Aerial Application

HighAcreage 

Field Crops

0.000369 0.000285 0.000016 0.000385 0.000301 3E-05 3E-05 0.00111 0.000856 0.0000479 0.00115 0.000904 1E-04 8E-05

M /L Liquids for 

Chemigation 

Application

Typical Field 

Crops 0.000108 0.0000832 0.00000465 0.000112 0.0000879 1E-05 8E-06 0.000323 0.00025 0.0000139 0.000337 0.000264 3E-05 2E-05

M /L Liquids for 

Chemigation 

Application

Sunflower, 

Dry Beans 0.000108 0.0000832 0.00000465 0.000112 0.0000879 1E-05 8E-06 0.000323 0.00025 0.0000139 0.000337 0.000264 3E-05 2E-05

M /L Liquids for 

Groundboom 

Application

Typical Field 

Crops 0.0000246 0.0000191 0.00000106 0.0000257 0.0000202 2E-06 2E-06 0.0000738 0.0000572 0.00000319 0.0000771 0.0000605 7E-06 5E-06
Page 26 of 30

Table C.1. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Additional PPE (PF5 Respirator, Double Layer Gloves). 

Exposure Scenario Crop or 

Target

Private Handler Commercial Handler

LADD (mg/kg/day) Total 

LADD3

(SL/G + 

PF5R)

Total

LADD3

(DL/G 

+PF5R)

Cancer Risk 

Estimate4

(SL/G +PF5R)

Cancer Risk 

Estimate

(DL/G+PF5

R)

LADD (mg/kg/day)

Total LADD3

(SL/G+PF5R)

Total 

LADD3

(DL/G+PF

5R)

Cancer 

Risk 

Estimate4

(SL/G+PF

5R)

Cancer 

Risk 

Estimate4

(DL/G+PF

5R)

Dermal

(SL/G)1

Dermal

(DL/G)

Inhalation2

(PF5R) Dermal

(SL/G)1

Dermal

(DL/G)1

Inhalation

(PF5R)2

M /L Liquids for 

Groundboom 

Application

HighAcreage 

Field Crops

0.0000616 0.0000476 0.00000266 0.0000643 0.0000503 6E-06 4E-06 0.000185 0.000143 0.00000797 0.000193 0.000151 2E-05 1E-05

Applicator

Applying Sprays for 

Aerial Application 

Typical Field 

Crops ND ND ND ND ND ND ND ND ND ND ND ND ND ND

Applying Sprays for 

Aerial Application

HighAcreage 

Field Crops

ND ND ND ND ND ND ND ND ND ND ND ND ND ND

Applying Sprays for 

Groundboom 

Application

Typical Field 

Crops 0.0000105 0.00000822 0.00000165 0.0000122 0.00000987 1E-06 9E-07 0.0000316 0.0000247 0.00000494 0.0000365 0.0000296 3E-06 3E-06

Applying Sprays for 

Groundboom 

Application

HighAcreage 

Field Crops

0.0000263 0.0000205 0.00000412 0.0000305 0.0000247 3E-06 2E-06 0.0000789 0.0000616 0.0000124 0.0000915 0.0000741 8E-06 7E-06

Applying 

Impregnated Dry 

Bulk Fertilizer -

Commercial 

Treatment

Sunflower, 

Dry Beans 0.0000188 0.000011 0.0000234 0.0000422 0.0000343 4E-06 3E-06 0.0000564 0.0000329 0.0000701 0.000127 0.000103 1E-05 9E-06

Applying 

Impregnated Dry 

Bulk Fertilizer - OnFarm Treatment

Sunflower, 

Dry Beans 0.00000943 0.00000548 0.0000116 0.000021 0.0000171 2E-06 2E-06 0.0000283 0.0000164 0.0000349 0.0000631 0.0000513 6E-06 5E-06

Applying Granules 

for Aerial 

Application

HighAcreage 

Field Crops

ND ND ND ND ND ND ND ND ND ND ND ND ND ND

Applying Granules 

for Tractor-Drawn 

Spreader 

Application

Sunflower, 

Dry Beans 0.0000118 0.00000688 0.0000145 0.0000263 0.0000214 2E-06 2E-06 0.0000354 0.0000207 0.0000435 0.0000789 0.0000642 7E-06 6E-06

Flagger for Aerial 

Application for 

Liquids

Typical Field 

Crops 0.0000343 0.0000304 0.00000743 0.0000417 0.0000377 4E-06 3E-06 0.000103 0.0000911 0.0000223 0.000125 0.000113 1E-05 1E-05

Flagger for Aerial 

Application for 

Liquids

HighAcreage 

Field Crops

0.0000343 0.0000304 0.00000743 0.0000417 0.0000377 4E-06 3E-06 0.000103 0.0000911 0.0000223 0.000125 0.000113 1E-05 1E-05

Flagger for Aerial 

Application for 

Granules

HighAcreage 

Field Crops

0.00000779 0.00000455 0.00000318 0.000011 0.00000773 1E-06 7E-07 0.0000234 0.0000136 0.00000955 0.0000329 0.0000232 3E-06 2E-06

1 “High Acreage Field Crops” include Sunflower and Dry Beans. “Typical Field Crops” include Cucumbers, Pumpkins, Summer Squash, Winter Squash, and Watermelons. ND = No Data; See Table 

8.1.2. and C.3.for aerial applicator scenarios which includes engineering controls.
Page 27 of 30

2 Dermal LADD (mg/kg/day) = Dermal dose (mg/kg/day) × [Days per year of exposure (days/yr) ÷ 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

3 Inhalation LADD (mg/kg/day) = Inhalation Dose (mg/kg/day) × [Days per year of exposure (days/yr) / 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

4 Total LADD (mg/kg/day) = Dermal LADD (mg/kg/day) + Inhalation LADD (mg/kg/day).

5 Cancer risk estimates = Total LADD × Q1

*

, where Q1

* = 0.089 (mg/kg/day)-1 

Table C.2. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Additional PPE (PF10 Respirator, Double Layer Gloves). 

Exposure Scenario Crop or 

Target

Private Handler Commercial Handler

LADD (mg/kg/day) Total 

LADD3

(SL/G + 

PF10R)

Total

LADD3

(DL/G 

+PF10R)

Cancer Risk 

Estimate4

(SL/G 

+PF10R)

Cancer Risk 

Estimate

(DL/G+

PF10R)

LADD (mg/kg/day) Total LADD3

(SL/G+PF10

R)

Total LADD3

(DL/G+

PF10R)

Cancer Risk 

Estimate4

(SL/G+PF10

R)

Cancer 

Risk 

Estimate4

(DL/G+

PF10R)

Dermal

(SL/G)1

Dermal

(DL/G) Inhalation2

(PF10R) Dermal

(SL/G)1

Dermal

(DL/G)1

Inhalation

(PF10R)2

M/L Granules for 

Aerial Application

HighAcreage 

Field Crops

0.0000679 0.0000334 0.0000618 0.00013 0.0000953 1E-05 8E-06 0.000204 0.0001 0.000186 0.000391 0.000286 3E-05 3E-05

M/L Granules for 

Tractor-Drawn 

Spreader 

Application

HighAcreage 

Field Crops

0.0000113 0.00000558 0.0000103 0.0000216 0.0000159 2E-06 1E-06 0.0000339 0.0000167 0.0000309 0.0000649 0.0000476 6E-06 4E-06

M/L Liquids for 

Commercial 

Treatment with 

Impregnated 

Fertilizers

Sunflower, 

Dry Beans ND ND ND ND ND ND ND ND ND ND ND ND ND ND

M/L Liquids for 

On-Farm Treatment 

with Impregnated 

Fertilizers

Sunflower, 

Dry Beans 0.0000491 0.0000381 0.00000106 0.0000502 0.0000392 4E-06 3E-06 0.000147 0.000114 0.00000319 0.00015 0.000118 1E-05 1E-05

M/L Liquids for 

Aerial Application

Typical Field 

Crops 0.000108 0.0000832 0.00000231 0.00011 0.0000856 1E-05 8E-06 0.000323 0.00025 0.00000693 0.00033 0.000257 3E-05 2E-05

M/L Liquids for 

Aerial Application

HighAcreage 

Field Crops

0.000369 0.000285 0.00000797 0.000376 0.000293 3E-05 3E-05 0.00111 0.000856 0.0000239 0.00113 0.000878 1E-04 8E-05

M /L Liquids for 

Chemigation 

Application

Typical Field 

Crops 0.000108 0.0000832 0.00000231 0.00011 0.0000856 1E-05 8E-06 0.000323 0.00025 0.00000693 0.00033 0.000257 3E-05 2E-05

M /L Liquids for 

Chemigation 

Application

Sunflower, 

Dry Beans 0.000108 0.0000832 0.00000231 0.00011 0.0000856 1E-05 8E-06 0.000323 0.00025 0.00000693 0.00033 0.000257 3E-05 2E-05

M /L Liquids for 

Groundboom 

Application

Typical Field 

Crops 0.0000246 0.0000191 0.000000531 0.0000251 0.0000195 2E-06 2E-06 0.0000738 0.0000572 0.00000159 0.0000752 0.0000586 7E-06 5E-06

M /L Liquids for 

Groundboom 

Application

HighAcreage 

Field Crops

0.0000616 0.0000476 0.00000133 0.0000629 0.0000489 6E-06 4E-06 0.000185 0.000143 0.00000398 0.000189 0.000147 2E-05 1E-05

Applicator

Applying Sprays for 

Aerial Application 

Typical Field 

Crops ND ND ND ND ND ND ND ND ND ND ND ND ND ND
Page 28 of 30

Table C.2. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Additional PPE (PF10 Respirator, Double Layer Gloves). 

Exposure Scenario Crop or 

Target

Private Handler Commercial Handler

LADD (mg/kg/day) Total 

LADD3

(SL/G + 

PF10R)

Total

LADD3

(DL/G 

+PF10R)

Cancer Risk 

Estimate4

(SL/G 

+PF10R)

Cancer Risk 

Estimate

(DL/G+

PF10R)

LADD (mg/kg/day) Total LADD3

(SL/G+PF10

R)

Total LADD3

(DL/G+

PF10R)

Cancer Risk 

Estimate4

(SL/G+PF10

R)

Cancer 

Risk 

Estimate4

(DL/G+

PF10R)

Dermal

(SL/G)1

Dermal

(DL/G) Inhalation2

(PF10R) Dermal

(SL/G)1

Dermal

(DL/G)1

Inhalation

(PF10R)2

Applying Sprays for 

Aerial Application

HighAcreage 

Field Crops

ND ND ND ND ND ND ND ND ND ND ND ND ND ND

Applying Sprays for 

Groundboom 

Application

Typical Field 

Crops 0.0000105 0.00000822 0.000000824 0.0000114 0.00000905 1E-06 8E-07 0.0000316 0.0000247 0.00000247 0.0000341 0.0000271 3E-06 2E-06

Applying Sprays for 

Groundboom 

Application

HighAcreage 

Crops

0.0000263 0.0000205 0.00000207 0.0000284 0.0000226 3E-06 2E-06 0.0000789 0.0000616 0.0000062 0.0000852 0.0000679 8E-06 6E-06

Applying 

Impregnated Dry 

Bulk Fertilizer -

Commercial 

Treatment

Sunflower, 

Dry Beans 0.0000188 0.000011 0.0000116 0.0000305 0.0000226 3E-06 2E-06 0.0000564 0.0000329 0.0000349 0.0000915 0.0000679 8E-06 6E-06

Applying 

Impregnated Dry 

Bulk Fertilizer - OnFarm Treatment

Sunflower, 

Dry Beans 0.00000943 0.00000548 0.0000058 0.0000152 0.0000113 1E-06 1E-06 0.0000283 0.0000164 0.0000174 0.0000457 0.0000339 4E-06 3E-06

Applying Granules 

for Aerial 

Application

HighAcreage 

Field Crops

ND ND ND ND ND ND ND ND ND ND ND ND ND ND

Applying Granules 

for Tractor-Drawn 

Spreader 

Application

Sunflower, 

Dry Beans 0.0000118 0.00000688 0.00000727 0.0000191 0.0000141 2E-06 1E-06 0.0000354 0.0000207 0.0000218 0.0000572 0.0000424 5E-06 4E-06

Flagger for Aerial 

Application for 

Liquids

Typical Field 

Crops 0.0000343 0.0000304 0.0000037 0.000038 0.0000341 3E-06 3E-06 0.000103 0.0000911 0.0000111 0.000114 0.000102 1E-05 9E-06

Flagger for Aerial 

Application for 

Liquids

HighAcreage 

Field Crops

0.0000343 0.0000304 0.0000037 0.000038 0.0000341 3E-06 3E-06 0.000103 0.0000911 0.0000111 0.000114 0.000102 1E-05 9E-06

Flagger for Aerial 

Application for 

Granules

HighAcreage 

Field Crops

0.00000779 0.00000455 0.00000159 0.00000938 0.00000613 8E-07 5E-07 0.0000234 0.0000136 0.00000476 0.0000281 0.0000184 3E-06 2E-06

1 “High Acreage Field Crops” include Sunflower and Dry Beans. “Typical Field Crops” include Cucumbers, Pumpkins, Summer Squash, Winter Squash, and Watermelons. ND = No Data; See Table 

8.1.2. and C.3.for aerial applicator scenarios which includes engineering controls.

2 Dermal LADD (mg/kg/day) = Dermal dose (mg/kg/day) × [Days per year of exposure (days/yr) ÷ 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

3 Inhalation LADD (mg/kg/day) = Inhalation Dose (mg/kg/day) × [Days per year of exposure (days/yr) / 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

4 Total LADD (mg/kg/day) = Dermal LADD (mg/kg/day) + Inhalation LADD (mg/kg/day).

5 Cancer risk estimates = Total LADD × Q1

*

, where Q1

* = 0.089 (mg/kg/day)-1 
Page 29 of 30

Table C.3. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Engineering Controls. 

Exposure Scenario Crop or Target

Private Handler Commercial Handler

LADD (mg/kg/day)

Total LADD3 Cancer Risk 

Estimate4

LADD (mg/kg/day)

Total LADD3 Cancer Risk 

Estimate4 Dermal1 Inhalation2

(No R) Dermal1 Inhalation2(No R)

M/L Granules for Aerial 

Application High-Acreage Field Crops 0.0000842 0.0000301 0.000114 1E-05 0.000253 0.0000904 0.000343 3E-05

M/L Granules for 

Tractor-Drawn Spreader 

Application

High-Acreage Field Crops 0.000014 0.00000503 0.0000191 2E-06 0.000042 0.0000151 0.0000572 5E-06

M/L Liquids for 

Commercial Treatment 

with Impregnated 

Fertilizers

Sunflower, Dry Beans 0.000674 0.000241 0.000915 8E-05 0.00202 0.000723 0.00274 2E-04

M/L Liquids for On-Farm 

Treatment with 

Impregnated Fertilizers

Sunflower, Dry Beans 0.0000113 0.00000403 0.0000152 1E-06 0.0000338 0.0000121 0.0000457 4E-06

M/L Liquids for Aerial 

Application Typical Field Crops 0.0000246 0.0000088 0.0000334 3E-06 0.0000738 0.0000264 0.0001 9E-06

M/L Liquids for Aerial 

Application High-Acreage Field Crops 0.0000842 0.0000301 0.000114 1E-05 0.000253 0.0000904 0.000343 3E-05

M /L Liquids for 

Chemigation Application Typical Field Crops 0.0000246 0.0000088 0.0000334 3E-06 0.0000738 0.0000264 0.0001 9E-06

M /L Liquids for 

Chemigation Application Sunflower, Dry Beans 0.0000246 0.0000088 0.0000334 3E-06 0.0000738 0.0000264 0.0001 9E-06

M /L Liquids for 

Groundboom Application Typical Field Crops 0.00000563 0.00000202 0.00000765 7E-07 0.0000169 0.00000605 0.0000229 2E-06

M /L Liquids for 

Groundboom Application High-Acreage Field Crops 0.000014 0.00000503 0.0000191 2E-06 0.000042 0.0000151 0.0000572 5E-06

Applicator

Applying Sprays for 

Aerial Application Typical Field Crops 0.00000596 0.00000052 0.00000648 6E-07 0.0000179 0.00000156 0.0000194 2E-06

Applying Sprays for 

Aerial Application High-Acreage Field Crops 0.0000204 0.00000178 0.0000223 2E-06 0.0000612 0.00000535 0.0000668 6E-06

Applying Sprays for 

Groundboom Application Typical Field Crops 0.00000334 0.00000104 0.00000439 4E-07 0.00001 0.00000313 0.0000132 1E-06

Applying Sprays for 

Groundboom Application High-Acreage Crops 0.00000832 0.00000261 0.0000109 1E-06 0.000025 0.00000782 0.0000328 3E-06

Applying Impregnated 

Dry Bulk Fertilizer -

Commercial Treatment

Sunflower, Dry Beans 0.00000784 0.0000214 0.0000293 3E-06 0.0000235 0.0000642 0.0000878 8E-06

Applying Impregnated 

Dry Bulk Fertilizer - OnFarm TreatmentSunflower, Dry Beans 0.00000392 0.0000107 0.0000146 1E-06 0.0000118 0.000032 0.0000439 4E-06

Applying Granules for 

Aerial Application High-Acreage Field Crops 0.0000167 0.000472 0.000489 4E-05 0.0000502 0.00142 0.00147 1E-04
Page 30 of 30

Table C.3. Occupational Handler Cancer Exposure and Risk Estimates for Ethalfluralin with Engineering Controls. 

Exposure Scenario Crop or Target

Private Handler Commercial Handler

LADD (mg/kg/day)

Total LADD3 Cancer Risk 

Estimate4

LADD (mg/kg/day)

Total LADD3 Cancer Risk 

Estimate4 Dermal1 Inhalation2

(No R) Dermal1 Inhalation2(No R)

Applying Granules for 

Tractor-Drawn Spreader 

Application

Sunflower, Dry Beans 0.00000327 0.0000133 0.0000166 1E-06 0.00000981 0.0000398 0.0000498 4E-06

Flagger for Aerial 

Application for Liquids Typical Field Crops ND ND ND ND ND ND ND ND

Flagger for Aerial 

Application for Liquids High-Acreage Field Crops ND ND ND ND ND ND ND ND

Flagger for Aerial 

Application for Granules High-Acreage Field Crops ND ND ND ND ND ND ND ND

1 “High Acreage Field Crops” include Sunflower and Dry Beans. “Typical Field Crops” include Cucumbers, Pumpkins, Summer Squash, Winter Squash, and Watermelons. ND = No Data

2 Dermal LADD (mg/kg/day) = Dermal dose (mg/kg/day) × [Days per year of exposure (days/yr) ÷ 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

3 Inhalation LADD (mg/kg/day) = Inhalation Dose (mg/kg/day) × [Days per year of exposure (days/yr) / 365 days/year] × [Years per lifetime of exposure (yrs) ÷ Lifetime expectancy (yrs)].

4 Total LADD (mg/kg/day) = Dermal LADD (mg/kg/day) + Inhalation LADD (mg/kg/day).

5 Cancer risk estimates = Total LADD × Q1

*

, where Q1

* = 0.089 (mg/kg/day)-1