Date: 

Subject: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

03-MAR-2016 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

Bcnsulide. Occupational and Residential Exposure Assessment in Support of 

Registration Review 

PC Code: 00980 I 

Decision No.: 507866 

Petition No.: NA 

DP Barcode: 0428877 

Registration No.: NA 

Regulatory Action: Registration 

Review 

Risk Assessment Type: Occupational/Residential Exposure Assessment 

TXR No.: NA 

Case No.: 2035 

CAS No.: 741-58-2 

MRID No.: NA 40 CFR: 180.241 

From: 

Through: 

To: 

Introduction 

Alexandra Gavelek, Biologist /L ~ { /t\, ~ Kelly 

Risk Assessment 

M. Lowe, E

Branch 

nvironm

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VII 

af Sc nti ·· ~~ 

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Health Effects Division (7509P) 

Michael Metzger, Branch Chief ' J /} !} )N 

Risk Assessment Branch YNII L 1

( k (- tl'v· {• 

Health Effects Division (7509P) f 

and 

J

Bridgett 

ennifer Tyler 

Bobowiec 

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Exposure Science Advisory Committee (ExpoSAC) I HED 

Margaret Hathaway I Kevin Costel lo 

Pesticide Re-evaluation Division (7508P) 

The Pesticide Re-Evaluation Division (PRO) requested that the Health Effects Division (HED) 

conduct an exposure and risk assessment for bensulide as part of registration review. 

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, 

Page I of 4 1 
including Pesticide Handlers Exposure Database Version I. I (PHED I . I); the Agricultural 

Handler Exposure Task Force (AHETF) database; the Outdoor Residential Exposure Task Force 

(ORETF) database; the Agricultural Reentry Task Force (ARTF) database; and the Residential 

SOPs (turf SOP). Some of these data are proprietary, and subject to the data protection 

provisions of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). 

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

(ExpoSAC) on October I, 2015. 

Page 2 of 41 
Page 3 of 41

Table of Contents

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

2.0 Risk Assessment Conclusions and Recommendations............................................................. 5

2.1 Summary of Risk Estimates.................................................................................................. 5

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

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

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

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

5.1 Residential Handler Exposure/Risk Estimates.................................................................... 11

5.2 Residential Post-application Exposure/Risk Estimates ...................................................... 14

5.3 Residential Risk Estimates for Use in Aggregate Assessment ........................................... 17

6.0 Non-Occupational Spray Drift Exposure and Risk Estimates................................................ 17

7.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates..... 22

8.0 Occupational Exposure and Risk Estimates ........................................................................... 22

8.1 Occupational Handler Exposure/Risk Estimates................................................................ 22

8.2 Occupational Post-application Exposure/Risk Estimates................................................... 28

8.2.1 Occupational Post-application Inhalation Exposure/Risk Estimates........................... 28

8.2.2 Occupational Post-application Dermal Exposure/Risk Estimates............................... 28

Appendix A. Summary of Occupational and Residential Non-cancer Algorithms..................... 31
Page 4 of 41

1.0 Executive Summary

The Pesticide Re-Evaluation Division (PRD) requested that the Health Effects Division (HED) 

conduct an exposure and risk assessment for bensulide as part of Registration Review.

Bensulide is an organophosphate herbicide; its mode of toxic action in mammals is the inhibition 

of the cholinesterase (ChE) enzyme. Bensulide is used for weed control in residential and 

occupational settings. Bensulide can be applied to vegetable crops, golf courses, and residential 

turf.

OPs exhibit a phenomenon known as steady-state AChE inhibition. After repeated dosing at the 

same dose level, the degree of inhibition comes into equilibrium with the production of new, 

uninhibited enzyme. At this point, the amount of AChE inhibition at a given dose remains 

consistent across duration. As such, the endpoints focus on acute (single-day) effects and steadystate effects. For this assessment, the duration of exposure is assumed to be steady-state and the 

toxicological endpoints are based on cholinesterase inhibition. 

The existing residential uses of bensulide on residential turf and golf courses have been 

reassessed to reflect updates to HED’s Residential SOPs. Residential handler risk estimates for 

applying liquid and granule products to residential lawns are of concern at currently labeled use 

rates. For residential handlers, a total aggregated risk index (ARI) was used since the LOCs for 

dermal exposure (1000) and inhalation exposure (3000) are different. The target ARI is 1; 

therefore, ARIs of less than 1 are risk estimates of concern. Residential post-application risk 

estimates for turf uses were assessed using chemical-specific turf transferable residue (TTR) data

for a liquid formulation, and accounting for the difference in toxicity between the parent, 

bensulide, and the oxon (i.e., by applying a 50x toxicity adjustment factor). Risk estimates are of 

concern for dermal exposure for adults and children conducting high exposure activities on

treated turf; for dermal exposure for adults and youths golfing; for hand-to-mouth exposure for

children on treated turf; and for episodic granule ingestion exposure.

A spray drift assessment was completed; spray drift risk estimates are based on an estimated 

deposited residue concentration as a result of the screening level agricultural application 

scenarios. Risk estimates related to spray drift are of concern at various distances from the edge 

of the field for adults and children (1 to <2 years) depending on the spray drift scenario. For 

adults, the screening level scenario indicates the LOC is exceeded at a distance of less than 25 

feet for application to vegetables and less than 75 feet for applications to golf courses. For 

children, the screening level scenario indicates the LOC is exceeded at a distance of 75 feet for 

application to vegetables and less than150 feet for application to golf courses. Drift reduction 

technologies, such as using coarser sprays and lowering boom height for groundboom sprayers, 

reduces risk concerns; however, there are still risk estimates of concern at the field edge in some 

cases. 

Occupational handler risk estimates were calculated for the registered uses on golf courses, turf, 

and vegetable crops. Different personal protective equipment (PPE) are required based on 

formulations and target crops. With the label-required PPE, all handler risk estimates are of 

concern. Even with the addition of maximum PPE or engineering controls, many occupational 

handler risk estimates remain of concern.
Page 5 of 41

Since bensulide is applied to vegetables as a preplant or preemergence application only, 

occupational post-application dermal exposure are not anticipated for these uses. Occupational 

post-application risk estimates were assessed for worker exposure to bensulide and bensulide 

oxon during maintenance activities on golf courses. Risk estimates were of concern (i.e., MOEs 

are < 1,000) until 5 days after treatment. The Worker Protection Statement interim REI is 12 

hours; this is the REI listed on the proposed labels, and is considered protective of postapplication exposure. However, there were risk estimates of concern related to golf course 

maintenance activities; therefore, HED is recommending that the REI for golf courses be revised 

on the label to address those concerns.

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

inhalation exposure assessment was not performed for bensulide 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 bensulide.

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; the Outdoor Residential Exposure Task Force (ORETF) 

database; the ARTF database; and the Residential SOPs (Turf SOP), 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

Residential handler risk estimates for applying liquid and granule products to residential lawns 

are of concern at currently labeled use rates. Residential post-application risk estimates for turf 

uses were also of concern; Risk estimates are of concern for dermal exposure for adults and 

children conducting high exposure activities are treated turf; for dermal exposure for adults and 

youths golfing; for hand-to-mouth exposure for children on treated turf; and for episodic granule 

ingestion exposure.

Risk estimates related to spray drift are of concern at various distances from the edge of the field 

for adults and children (1 to <2 years) depending on the spray drift scenario. For adults, the 

screening level scenario requires a distance of 25 feet for application to vegetables and 75 feet 

for application to golf courses. For children, the screening level scenario requires a distance of 

75 feet for application to vegetables and 150 feet for application to golf courses. Drift reduction 

 

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

http://www.epa.gov/pesticides/science/post-app-exposure-data.html
Page 6 of 41

technologies, such as using coarser sprays and lowering boom height for groundboom sprayers, 

reduces risk concerns; however there are still risk estimates of concern at the field edge in some 

cases. 

Occupational handler risk estimates were calculated for the registered uses on golf courses, turf, 

and vegetable crops. With the label-required PPE, all handler risk estimates are of concern. Even 

with applying maximum PPE or engineering controls, many occupational handler risk estimates 

are of concern.

Occupational post-application risk estimates were assessed for worker exposure during 

maintenance activities on golf courses; risk estimates were of concern until 5 days after 

treatment. 

2.2 Data Deficiencies and Requirements

There are no data deficiencies. Chemical-specific turf transferable residue (TTR) data are 

available; DFR data are not required based on the registered use pattern.

3.0 Hazard Characterization

Bensulide is Toxicity Category II for acute oral toxicity. The acute lethal toxicity is low for other 

routes, Toxicity Category III or IV for dermal and inhalation toxicity; and dermal and eye 

irritation. It is not a dermal sensitizer.

Table 3.0.1. Acute Toxicity Profile - Bensulide

Guideline

No. Study Type MRID # Results Toxicity 

Category

870.1100 Acute oral [rat] 00097921 

92005011

LD50 = 360 mg/kg (M)

LD50 = 270 mg/kg (F) II

870.1200 Acute dermal [rat] 41597501 LD50 ≥ 2000 mg/kg III

870.1200 Acute dermal [rabbit] 00097921 LD50 > 5000 mg/kg IV

870.1300 Acute inhalation [rat] 41646201 LC50 > 1.75 mg/L III

870.2400 Acute eye irritation [rabbit] 41597502 mild irritant III

870.2500 Acute dermal irritation [rabbit] 00097921 

92005012 mild irritant IV

870.2600 Dermal sensitization [guinea pig] 00160075 not a sensitizer NA

OPs exhibit a phenomenon known as steady-state AChE inhibition. After repeated dosing at the 

same dose level, the degree of inhibition comes into equilibrium with the production of new, 

uninhibited enzyme. At this point, the amount of AChE inhibition at a given dose remains 

consistent across duration. As such, the endpoints focus on acute (single-day) effects and steadystate effects. 

HED’s Hazard Science Policy Council (HASPOC) recommended a waiver for the 

immunotoxicity study (Van Alstine, 2013; TXR # 0056738). Furthermore, HASPOC 

recommended waivers for the 6-month ocular toxicity study in dog, and developmental and 

subchronic neurotoxicity studies; however, the subchronic inhalation study is required and is 

considered a datagap (Leshin, 2015, TXR # 0057280).
Page 7 of 41

The toxicological endpoints for risk assessment are summarized in Tables 3.0.2 and 3.0.3 below. 

The endpoint for all exposure scenarios is RBC AChEI and points of departure (PODs) were 

selected from high quality, well-conducted CCA rat studies. The POD for the steady-state (a 21-

day assessment) incidental oral, dermal, and inhalation scenarios is 6 mg/kg/day. The FQPA 

safety factor (10X) has been retained for infants, children, youths, and women of child-bearing 

age for all exposure scenarios due to uncertainty in the human dose-response relationship for 

neurodevelopmental effects. Additionally, for inhalation exposures, a database uncertainty 

factor of 30X was applied due to uncertainty in the human dose-response relationship for 

neurodevelopmental effects and lack of an inhalation toxicity study. For all exposure scenarios, 

interspecies (10X) and intraspecies (10X) uncertainty factors were applied. As a result, a total 

uncertainty factor of 1000X was applied for all non-cancer exposure scenarios, except inhalation 

exposures (total uncertainty factor = 3000X).

As a CCA study is not available for the bensulide oxon, a default toxicity adjustment factor 

(TAF) of 50X was applied to the bensulide oxon (assuming the oxon is 50X the toxicity of the 

parent).

Table 3.0.2. Summary of Toxicological Doses and Endpoints and Points of Departure for Bensulide in 

Dietary and Non-Occupational Human Health Risk Assessments a

Exposure

Scenario

Point of 

Departure

(mg/kg/day)

Uncertainty/FQPA 

Factors

RFD, PAD, & LOC

for Risk 

Assessment

Study and Toxicological

Effects

Acute 

Dietary (All 

Populations)

BMDL10 = 11 

mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF = 10x

Acute RfD = aPAD = 

0.011 mg/kg/day

Acute CCA Study (MRID 

49433502) in the rat 

BMD10 = 16 mg/kg/day

Inhibition of RBC ChE in 

female pups (PND 11)

Incidental 

Oral 

(Steady-state)

BMDL10 = 6 

mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF = 10x

Residential LOC for 

MOE = 1000x 

Repeated-Dose CCA Study 

(MRID 49466201) in the rat 

BMD10 = 8 mg/kg/day

Inhibition of RBC ChE in 

male pups (PND 11 initially)

Dermal 

(Steady-state)

BMDL10 = 6 

mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF = 10x

DAF = 10%

Residential LOC for 

MOE = 1000x

Repeated-Dose CCA Study 

(MRID 49466201) in the rat 

BMD10 = 8 mg/kg/day

Inhibition of RBC ChE in 

male pups (PND 11 initially)

Inhalation 

(Steady-state)

BMDL10 = 6 

mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF/UFDB = 

30x

Residential LOC for 

MOE = 3000x 

Repeated-Dose CCA Study 

(MRID 49466201) in the rat 

BMD10 = 8 mg/kg/day

Inhibition of RBC ChE in

male pups (PND 11 initially)

Cancer (oral, 

dermal, 

inhalation)

Bensulide has been classified as a Group E substance; the chemical is not likely to be 

carcinogenic in humans via relevant routes of exposure.
Page 8 of 41

a 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. BMDL = lower limit of the bench mark dose. 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). SF = 

Safety Factor. PAD = population adjusted dose (a = acute, c = chronic). RfD = reference dose. MOE = margin of 

exposure. LOC = level of concern. 

FQPA SF retained for infants, children, youths, and women of childbearing age for all exposure scenarios due to 

uncertainty in the human dose-response relationship for neurodevelopmental effects. UFDB for inhalation exposures 

= database uncertainty factor incorporating uncertainty in the human dose-response relationship for 

neurodevelopmental effects and the lack of a subchronic inhalation toxicity study.

Table 3.0.3 Summary of Toxicological Doses and Endpoints for Bensulide for Use in Occupational Human 

Health Risk Assessments a

Exposure/ 

Scenario

Point of 

Departure

Uncertainty/

FQPA 

Factors

LOC for Risk 

Assessment

Study and Toxicological Effects

Dermal 

Steady-state

BMDL10 = 6 

mg/kg/day

UFA = 10x

UFH = 10x

UFDB = 10X

DAF = 10%

Occupational 

LOC for MOE = 

1000x

Repeated-Dose CCA Study (MRID 

49466201) in the rat 

BMD10 = 8 mg/kg/day

Inhibition of RBC ChE in male pups 

(PND 11 initially)

Inhalation 

Steady-state

BMDL10 = 6 

mg/kg/day

UFA = 10x

UFH = 10x

UFDB = 30X

Occupational 

LOC for MOE = 

3000x

Repeated-Dose CCA Study (MRID 

49466201) in the rat 

BMD10 = 8 mg/kg/day

Inhibition of RBC ChE in male pups 

(PND 11 initially)

Cancer (oral, 

dermal, 

inhalation)

Bensulide has been classified as a Group E substance; the chemical is not likely to be 

carcinogenic in humans via relevant routes of exposure.

a 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. BMDL = lower limit of the bench mark dose. 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. 

UFDB for occupational dermal exposures = database uncertainty factor for uncertainty in the human dose-response 

relationship for neurodevelopmental effects.

UFDB for occupational inhalation exposures = database uncertainty factor incorporating uncertainty in the human 

dose-response relationship for neurodevelopmental effects and the lack of a subchronic inhalation toxicity study.

Absorption

A dermal absorption factor of 10% was used for the exposure assessment and is based on 

comparing the results occurring in an oral developmental rat study to the 21-day dermal rat 

study. 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
Page 9 of 41

For adults, when an endpoint is not sex-specific (i.e., the endpoints are based on developmental 

or fetal effects) a body weight of 80 kg is typically used in risk assessment; however, in this case, 

a female-specific body weight of 69 kg was used. While the endpoint of concern, RBC AChE 

inhibition, is not sex-specific, the female-specific body weight was used to protect for pregnant 

women due to uncertainty in the human dose-response relationship for neurodevelopmental 

effects. Body weights of 57, 32 and 11 kg was used to assess exposure to children 11 to <16 

years, 6 to <11 years, and 1 to <2 years old.

4.0 Use Profile 

Bensulide is used for weed control in residential and occupational settings. Bensulide can be 

applied to vegetable crops, golf courses, and residential turf. A summary of bensulide uses is 

listed in Table 4.1.

Table 4.1. Summary of Directions for Use of Bensulide.

Applic. Timing, 

Type, and 

Equip.

Formulation 

[EPA Reg. 

No.]

Applic. 

Rate (lb 

ai/A)

Max. 

Seasonal 

Applic. Rate 

(lb ai/A)

PHI (days) Use Directions and Limitations

Turf (Golf Courses and Residential Lawns)

Groundboom or 

low pressure 

turfgun,

Handwand for 

spot treatment 

Watered in

Liquid 

4 lb ai/gal

(46% ai)

EPA Reg. No. 

2217-696

12.5 lb 

ai/acre 25 lb ai/acre NA

PPE: baseline, gloves, PF5 respirator

Tractor drawn 

spreader, Push 

type spreader

Watered in

Granular

7% ai

EPA Reg. No. 

2217-778

12.6 lb 

ai/acre

25.2 lb 

ai/acre NA

PPE: Loaders, spreader applicator: 

Coveralls, gloves, PF5 respirator

All others: baseline, gloves

For hire applicators must wear PF5 

respirator

Cannot be applied aerially

Only on lawns

Push type 

spreader only

Granular

3.6% ai

EPA Reg. No. 

2217-838

12.5 lb 

ai/acre NA NA

No PPE listed

Hand-held rotary broadcast spreader 

prohibited

Tractor drawn 

spreader, push 

type spreader 

Granular

8.5% ai

EPA Reg. No 

9198-172

12.4 lb 

ai/acre NA NA

PPE: loaders, spreader applicator:

coveralls, gloves, PF5 respirator

All others: baseline, gloves

Golf courses only

Tractor drawn

spreader or push 

type spreader

Granular

5.25% ai

EPA Reg. No. 

9198-176

16 lb ai/acre 32 lb ai/acre NA

Not for sale or use by homeowners

PPE: push spreaders and loader: 

coveralls, gloves, PF5 respirator

Other applicators: baseline, gloves

For hire applicators must wear PF5 

respirator
Page 10 of 41

Table 4.1. Summary of Directions for Use of Bensulide.

Applic. Timing, 

Type, and 

Equip.

Formulation 

[EPA Reg. 

No.]

Applic. 

Rate (lb 

ai/A)

Max. 

Seasonal 

Applic. Rate 

(lb ai/A)

PHI (days) Use Directions and Limitations

Watered in

Golf courses only

Groundboom, low 

pressure turfgun, 

LP Handwand for 

spot treatment 

Liquid

46.4% ai

4 lb ai/gal

EPA Reg. No. 

10163-196

12.5 lb 

ai/acre 25 lb ai/acre NA

PPE: Mixer/loader: baseline, gloves, 

PF5 respirator

Applicator and other: baseline, 

gloves; for hire applicators must 

wear PF5 respirator

Golf courses only

Watered in

Granular

12.5% ai

EPA Reg. No. 

10163-198

12.5 lb 

ai/acre 25 lb ai/acre NA

PPE: Loaders, spreader applicator: 

coveralls, gloves, respirator

Other applicators: baseline, gloves, 

respirator

Golf courses only

Tractor drawn 

spreader or pushtype spreader

Watered in

Granular

3.6% ai

EPA Reg. No. 

10163-199

12.5 lb 

ai/acre NA NA

PPE: Loaders and spreader 

applicators: coveralls, gloves,

eyewear, for-hire applicators must 

wear respirator

All other applicators: baseline, 

gloves, respirator

Hand-held rotary spreaders are 

prohibited

Golf courses only

Tractor drawn 

spreader or pushtype spreader

Watered in

Granular

7% ai

EPA Reg. No. 

10163-204

12.6 lb 

ai/acre 25 lb ai/acre NA

PPE: loaders and spreader 

applicators: coveralls, gloves, 

respirator; others: baseline, gloves, 

for-hire applicators must wear 

respirator

Residential lawns 

only

RTU Garden hose 

sprayer

46.4% ai

EPA Reg. No. 

10163-205

16 fl oz 

product/ 

2500 sq. ft

8.7 lb ai/A

NA NA

No PPE listed

Cucurbit vegetables 

Groundboom, 

Chemigation, 

Handgun

Preplant or 

preemergence

Emulsifiable 

Liquid

4 lb ai/gal

EPA Reg. No. 

10163-200

6 lb ai/acre NA NA

PPE: baseline, gloves; Mixers, 

loaders and commercial applicators 

must wear a PF5 respirator

May not be applied by aircraft

9 lb ai/acre NA NA

SLN label – CA 960003

Brassica (cole) leafy vegetables; leafy vegetables

Groundboom, 

Chemigation, 

Handgun

Emulsifiable 

Liquid

4 lb ai/gal

6 lb ai/acre 6 lb ai/acre NA

PPE: baseline, gloves; Mixers, 

loaders and commercial applicators 

must wear a PF5 respirator

Do not use on spinach or Swiss 

Chard
Page 11 of 41

Table 4.1. Summary of Directions for Use of Bensulide.

Applic. Timing, 

Type, and 

Equip.

Formulation 

[EPA Reg. 

No.]

Applic. 

Rate (lb 

ai/A)

Max. 

Seasonal 

Applic. Rate 

(lb ai/A)

PHI (days) Use Directions and Limitations

Preplant or 

preemergence 

EPA Reg. No. 

10163-200

May not be applied by aircraft

9 lb ai/acre 9 lb ai/acre NA SLN label – NJ 070001

Fruiting vegetables 

Groundboom, 

Chemigation, 

Handgun

Preplant or 

preemergence

Emulsifiable 

Liquid

4 lb ai/gal

EPA Reg. No. 

10163-200

6 lb ai/acre NA NA

PPE: baseline, gloves; Mixers, 

loaders and commercial applicators 

must wear a PF5 respirator

May not be applied by aircraft

Carrots

Groundboom, 

Chemigation, 

Handgun

Preplant or 

Preemergence 

Emulsifiable 

Liquid

4 lb ai/gal

EPA Reg. No. 

10163-200

5 lb ai/acre 5 lb ai/acre NA

PPE: baseline, gloves; Mixers, 

loaders and commercial applicators 

must wear a PF5 respirator

May not be applied by aircraft

Dry Bulb Vegetables 

Groundboom, 

Chemigation, 

Handgun

Preplant or 

Preemergence 

Emulsifiable 

Liquid

4 lb ai/gal

EPA Reg. No. 

10163-200

6 lb ai/acre 6 lb ai/acre NA

PPE: baseline, gloves; Mixers, 

loaders and commercial applicators 

must wear a PF5 respirator

May not be applied by aircraft

NA = Not Applicable; early season application

5.0 Residential Exposure and Risk Estimates

The existing residential uses that have been reassessed in this document to reflect updates to 

HED’s 2012 Residential SOPs2along with policy changes for body weight assumptions. The 

revision of residential exposures will impact the human health aggregate risk assessment for 

bensulide. Exposure to bensulide is assessed for handler scenarios; exposure to bensulide and 

bensulide oxon was assessed for post-application scenarios.

5.1 Residential 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 tasks related to applications and that 

exposures can vary depending on the specifics of each task. Residential handlers are addressed 

somewhat differently by HED as homeowners are assumed to complete all elements of an 

application without use of any protective equipment.

 

2 Available: http://www.epa.gov/pesticides/science/residential-exposure-sop.html
Page 12 of 41

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

following scenarios: 

 Mixing/loading/applying liquid and granular formulations dispersed by hand to 

residential turf/lawns, and 

 Mixing/loading/applying liquid and granular formulations with handheld equipment to 

residential turf/lawns.

Residential Handler Exposure Data and Assumptions

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

handler risk assessments. Each assumption and factor is detailed below.

Application Rate:

Application rates are listed in Table 4.1.

Unit Exposures and Area Treated or Amount Handled:

Unit exposure values and estimates for area treated or amount handled were taken from HED’s 

2012 Residential SOPs3.

Exposure Duration: 

Residential handler exposure is assessed as steady-state in duration.

Residential Handler Non-Cancer Exposure and Risk Estimate Equations

The algorithms used to estimate exposure and dose for residential handlers can be found in the 

2012 Residential SOPs4.

Combining Exposures/Risk Estimates:

A total aggregated risk index (ARI) was used since the LOCs for dermal exposure (1000) and 

inhalation exposure (3000) are different. The target ARI is 1; therefore, ARIs of less than 1 are 

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

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

Summary of Residential Handler Non-Cancer Exposure and Risk Estimates

A summary of residential handler risk estimates is provided in Table 5.1.1 below. Most 

residential handler risk estimates are of concern (ARI < 1). 

 

3 Available: http://www.epa.gov/pesticides/science/residential-exposure-sop.html

4 Available: http://www.epa.gov/pesticides/science/residential-exposure-sop.html
Page 13 of 41

Table 5.1.1. Residential Handler Non-cancer Exposure and Risk Estimates for Bensulide.

Exposure Scenario

Dermal Unit 

Exposure 

(mg/lb ai)

Inhalation Unit 

Exposure 

(mg/lb ai)

Maximum 

Application 

Rate1

Area Treated or 

Amount Handled 

Daily2

Dermal Inhalation Total

Dose 

(mg/kg/day)3

MOE

(LOC = 1000)4

Dose 

(mg/kg/day)5

MOE

(LOC = 3000)6 ARI7

Mixer/Loader/Applicator

Liquid Concentrate, 

Handwand, Lawns 63 0.018 0.16 lb ai/gal 5 gallons 0.073 82 0.0002 29,000 0.081

Ready-to-use, hose end 

sprayer, Lawns 6.26 0.034 8.7 lb ai/acre 0.5 acres 0.039 150 0.0021 2,800 0.13

Liquid, Backpack, 

Lawns 130 0.14 0.16 lb ai/gal 5 gallons 0.15 40 0.0016 3,700 0.039

Granule, Push type 

rotary spreader, Lawns 0.81 0.0026 12.5 lb ai/acre 0.5 acres 0.0073 820 0.0002 25,000 0.75

Granule, belly grinder, 

lawns 360 0.039

0.00029 lb 

ai/ft2

1200 ft2 0.18 33 0.0002 31,000 0.033

Granule, Spoon, Lawns 6.2 0.087

100 ft2

0.00026 23,000 0.000037 160,000 16

Granule, Cup, Lawns 0.11 0.013 0.0000046 1,300,000 0.0000055 1,100,000 290

Granule, Hand 

dispersal, Lawns 160 0.38 0.0067 890 0.00016 38,000 0.83

Granule, Shaker can, 

Lawns 0.11 0.013 0.0000046 1,300,000 0.0000055 1,100,000 290

1 Based on registered labels (see Table 4.1).

2 Based on HED’s 2012 Residential SOPs (http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/standard-operating-procedures-residential-pesticide).

3 Dermal Dose = Dermal Unit Exposure (mg/lb ai) × Application Rate (lb ai/acre, ft2 or gal) × Area Treated or Amount Handled (A or ft2/day or gallons/day) × Dermal 

Absorption Factor (10%) ÷ Body Weight (69 kg).

4 Dermal MOE = Dermal NOAEL (6 mg/kg/day) ÷ Dermal Dose (mg/kg/day).

5 Inhalation Dose = Inhalation Unit Exposure (mg/lb ai) × Application Rate (lb ai/acre, ft2 or gal) × Area Treated or Amount Handled (A or ft2/day or gallons/day) ÷ Body Weight 

(69 kg).

6 Inhalation MOE = Inhalation NOAEL (6 mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

7 ARI = Aggregate Risk Index = 1÷ [(Dermal LOC ÷ Dermal MOE) + (Inhalation LOC ÷ Inhalation MOE)].
Page 14 of 41

5.2 Residential Post-application Exposure/Risk Estimates

There is the potential for post-application exposure for individuals exposed as a result of being in 

an environment that has been previously treated with bensulide. The quantitative exposure/risk 

assessment for residential post-application exposures is based on the following scenarios: 

 Dermal exposure from high contact with treated turf (adults and children 1 to < 2 years 

old)

 Dermal exposure from golfing (adults and youth 11 to < 16 years old and youth 6 to < 11 

years old)

 Dermal exposure from mowing treated turf (adult and youth 11 to < 16 years old)

 Incidental ingestion (i.e., hand-to-mouth, object-to-mouth, soil ingestion exposure) from 

contact with treated turf (children 1 to < 2 years old)

 Episodic granular ingestion (children 1 to < 2 years old)

The lifestages selected for each post-application scenario are based on an analysis provided as an 

Appendix in the 2012 Residential SOPs5. While not the only lifestage potentially exposed for 

these post-application scenarios, the lifestage that is included in the quantitative assessment is 

health protective for the exposures and risk estimates for any other potentially exposed lifestage.

Residential Post-application Exposure Data and Assumptions

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

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

SOPs5.

Application Rate:

Application rates are listed in Table 4.1. 

Turf Transferable Residue (TTR) Data:

Liquid Formulations:

Chemical-specific TTR data are available for bensulide and are summarized in Table 

5.2.1 (HED review: D413875, 10/29/13, A. Rivera-Lupianez). The study includes TTR 

data on bensulide and its metabolite, bensulide oxon, that transferred from turf treated 

with a liquid formulation containing bensulide at a rate of 12.5 lb ai/A. The product was 

watered in immediately following the application. Residues were sampled using the 

modified California Roller technique. First-order dissipation kinetics were assumed in 

order to generate dissipation curves for bensulide and combined residues of bensulide and 

bensulide oxon. The summary of statistics include only post-irrigation measurements as 

the product labels require the product to be watered in. Due to the differences in the 

dissipation of bensulide and the oxon, residues of the oxon were adjusted by the TAF of 

50 [oxon residue, ug/cm2* 50X TAF], and total residues (bensulide + adjusted oxon) 

were used to determine the risk resulting from exposures following bensulide 

 

5 Available: http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/standard-operating-proceduresresidential-pesticide
Page 15 of 41

applications. For assessment of residential post-application exposures, the predicted day 

0 combined residues (0.479 ug/cm2) were used in the exposure calculations (see Table 

5.2.1 below).

Table 5.2.1. Regression Summary for Turf Treated with BENSUMEC 4LF (MRID 44799001)

Statistic Bensulide Bensulide oxon Combined 

residues

Combined 

Residue with 

50x factor for 

oxon1

Actual Application Rate (lb ai/A) 12.6

Actual Average 8-12 hours 

(μg/cm2)

(post-irrigation )

0.2093 0.0057 0.2144 0.4627

Predicted Day 0 (μg/cm2)

(post-irrigation ) 0.201 0.002 0.206 0.479

Slope -0.27 -0.049 -0.271 -0.303

Half-life (days) 2.6 14.2 2.6 2.3

R

2 0.897 0.0285 0.8934 0.8123

Bolded value represents residue value used in post-application exposure calculations.

1 Combined residue, ug/cm2 = [ (oxon residue, ug/cm2

) * 50 X TAF] + [bensulide residue, ug/cm2)

Solid Formulations: 

Chemical-specific TTR data are not available for solid formulations applied to turf; liquid 

TTR data were used as surrogate. This is considered a health protective approach since, 

in general, granular formulations tend to result in lower percent transfer from turf than do 

liquid formulations (e.g., the 2012 Residential SOP turf default percent transfer factor is 

1% for liquids and 0.2% for granulars).

Exposure Duration: 

The exposure duration for residential post-application exposures is steady-state. Granule 

ingestion is considered episodic and thus is an acute duration.

Residential Post-application Non-Cancer Exposure and Risk Equations

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

the 2012 Residential SOPs6.

Combining Exposure and Risk Estimates

Since dermal and incidental oral exposure routes share a common toxicological endpoint, risk 

estimates have been combined for those routes. The incidental oral scenarios (i.e., hand-tomouth and object-to-mouth) should be considered inter-related and it is likely that they occur 

interspersed amongst each other across time. Combining these scenarios with the dermal 

exposure scenario would be overly-conservative because of the conservative nature of each 

 

6 Available: http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/standard-operating-proceduresresidential-pesticide
Page 16 of 41

individual assessment. Therefore, the post-application exposure scenarios that were combined 

for children 1 < 2 years old are the dermal and hand-to-mouth scenarios. This combination 

should be considered a protective estimate of children’s exposure.

Summary of Residential Post-application Non-Cancer Exposure and Risk Estimates

A summary of the residential post-application exposure and risk estimates for bensulide and its 

oxon is in Tables 5.2.2 (for the liquid formulations) and 5.2.3 (for the granular formulations) 

below. Risk estimates are of concern (MOEs < 1000) for dermal exposure for adults and 

children conducting high exposure activities are treated turf; for dermal exposure for adults and 

youths golfing; for hand-to-mouth exposure for children on treated turf; and for episodic granule

ingestion exposure.

Table 5.2.2. Residential Post-application Non-cancer Exposure and Risk Estimates for Bensulide + Oxon (Liquid 

Formulations).

Lifestage

Post-application Exposure 

Scenario Application 

Rate1

Dose 

(mg/kg/day)2

MOEs

(LOC = 

1000)3

Combined Routes

(X indicates included 

in Combined MOE)

Combined MOEs4

(LOC = 1000) Use Site Route of 

Exposure

Adult

Lawns/ Turf

Dermal – Turf

12.5 lb ai/A

0.187 32

NA

Dermal - Mowing 0.0038 1,600

Dermal – Golfing 0.0147 410

Youth (11 to 

< 16 years)

Dermal- Mowing 0.00378 1,600

Dermal – Golfing 0.0148 410

Youth (6 to < 

11 years) Dermal- Golfing 0.0174 350

Child (1 to < 

2 years)

Dermal - Turf 0.32 19 X

16 HTM 0.0656 91 X

OTM 0.00199 3,000 NA Soil Ingestion 0.00042 14,000

1 Based on registered labels (see Table 4.1). Predicted Day 0 combined (bensulide + adjusted oxon) residue value (0.479 ug/cm2; from MRID 

44799001) used in calculations.

2 Dose (mg/kg/day) algorithms provided in 2012 Residential SOPs (http://www2.epa.gov/pesticide-science-and-assessing-pesticiderisks/standard-operating-procedures-residential-pesticide).

3 MOE = Dermal and Incidental Oral POD (6 mg/kg/day) ÷ Dose (mg/kg/day).

4 Combined MOE = 1 ÷ (1/dermal MOE) + (1/incidental oral MOE), where applicable.

Table 5.2.3. Residential Post-application Non-cancer Exposure and Risk Estimates for Bensulide + Oxon (Solid 

Formulations).

Lifestage

Post-application Exposure 

Scenario Application 

Rate1

Dose 

(mg/kg/day)2

MOEs

(LOC = 

1000)3

Combined Routes

(X indicates included 

in Combined MOE)

Combined MOEs4

(LOC = 1000) Use Site Route of 

Exposure

Adult

Lawns/ Turf

Dermal – Turf 12.5 lb ai/A 0.2082 29

NA

Dermal - Mowing 0.0038 1,600

Dermal – Golfing 16 lb ai/A 0.0188 320

Youth (11 to 

< 16 years)

Dermal- Mowing 12.5 lb ai/A 0.00378 1,600

Dermal – Golfing

16 lb ai/A

0.0189 320

Youth (6 to < 

11 years) Dermal- Golfing 0.0222 270

Child (1 to < 

2 years)

Dermal - Turf

12.5 lb ai/A

0.3527 17 X

16 HTM 0.0325 180 X

OTM 0.00199 3,000 NA Soil Ingestion 0.00042 14,000
Page 17 of 41

Table 5.2.3. Residential Post-application Non-cancer Exposure and Risk Estimates for Bensulide + Oxon (Solid 

Formulations).

Lifestage

Post-application Exposure 

Scenario Application 

Rate1

Dose 

(mg/kg/day)2

MOEs

(LOC = 

1000)3

Combined Routes

(X indicates included 

in Combined MOE)

Combined MOEs4

(LOC = 1000) Use Site Route of 

Exposure

Episodic Granule 

Ingestion 3.41 3.2

1 Based on registered labels (see Table 4.1). Predicted Day 0 combined (bensulide + adjusted oxon) residue value (0.479 ug/cm2; from MRID 

44799001) used in calculations.

2 Dose (mg/kg/day) algorithms provided in 2012 Residential SOPs (http://www2.epa.gov/pesticide-science-and-assessing-pesticiderisks/standard-operating-procedures-residential-pesticide).

3 MOE = Dermal and Incidental Oral POD (6 mg/kg/day) ÷ Dose (mg/kg/day).

4 Combined MOE = 1 ÷ (1/dermal MOE) + (1/incidental oral MOE), where applicable.

5.3 Residential Risk Estimates for Use in Aggregate Assessment

As the residential turf scenarios are risks of concern, there are no residential risk estimates 

recommended for steady state aggregate assessment.

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 indirect 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 onto 50 feet wide lawns 

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.7 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 bensulide. 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 

 

7 This approach is consistent with the requirements of the EPA’s Worker Protection Standard.
Page 18 of 41

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). 

For bensulide, chemical-specific turf transferable residue (TTR) data are available. See Section 

5.2 for a description of the TTR data. The data include measurements on bensulide and the 

oxon. For assessment of exposures resulting from spray drift, the predicted day 0 combined 

(bensulide + adjusted oxon) residue value (0.479 ug/cm2) was adjusted for differences in 

application rate between the study and the registered agricultural uses, and the adjusted residue 

value was used in the exposure calculations.

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.8 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 

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). Table 6.1 provides the screening level drift related risk estimates. In many cases, 

risk estimates 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.

Combined 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. Bensulide is registered in both 

liquid and granular formulation end-use products. Granular formulations, applied as solid 

materials and no liquid spray, have different drift patterns than liquid sprays, and as such need to 

be considered in a separate analysis. However, from a human health perspective, off-site 

movement of granular products would result in lower risk estimates than those for liquid 

products (e.g., less drift occurs and there is less exposure uptake for granules). In most cases 

pesticides also have liquid end-use products and an analysis for them would be protective of 

potential risks from granular drift; thus granular products are not assessed. 

Bensulide is registered on vegetable crops and golf courses and can be applied via groundboom 

equipment at a maximum single application rate of 6 lb ai/A for vegetable crops (9 lb ai/A on 

SLN labels) and 12.5 lb ai/acre for golf courses. The recommended drift scenario screening 

level options are listed below:

 

8 http://www.agdrift.com/ 
Page 19 of 41

 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. 

In addition to the screening level spray drift scenarios described above, additional results are 

provided which represent viable drift reduction technologies (DRTs) that represent potential risk 

management options. In particular, different spray qualities have been considered as well as the 

impact of other application conditions (e.g., boom height and crop canopy conditions).

Dermal risk estimates were calculated for adults. Dermal and incidental oral risk estimates for 

children (1 to <2 years old) were combined because the toxicity endpoint for each route of 

exposure is the same (RBC AChE inhibition). The total applicable LOC is 1000, so MOEs 

<1000 represent risk estimates of concern. 

Risk estimates related to spray drift are of concern at various distances from the edge of the field 

for adults and children (1 to <2 years) depending on the spray drift scenario. Adult and children 

risk estimates are summarized in Table 6.1. For adults, the screening level scenario of a high 

boom and very fine to fine spray indicates the LOC is exceeded at a distance of less than 25 feet

for application to vegetables, less than 50 feet for application to SLN vegetables, and less than 75 

feet for application to golf courses to reach a dermal MOE ≥ 1000. For children, the screening 

level scenario indicates the LOC is exceeded at a distance of less than 75 feet for application to 

vegetables, less than 100 feet for application to SLN vegetables, and less than 150 feet for 

application to golf courses to reach a combined (dermal and incidental oral) MOE ≥1000. Drift 

reduction technologies, such as using coarser sprays and lowering boom height for groundboom

sprayers, reduces risk concerns; however there are still risk estimates of concern at the field edge

for some scenarios. 
Page 20 of 41

Table 6.1. Spray Drift Risk Estimate Summary for Bensulide.

Crop / 

Application 

Type

Spray Type/ 

Nozzle 

Configuration

Application 

Rate 

(lb ai/A)

Estimated 

TTR

(ug/cm2)

MOE at Different Distances from Edge of Field

LOC = 1000

At Edge 10 Feet 25 Feet 50 Feet 75 Feet 100 Feet 125 feet 150 feet 200 feet 250 feet 300 feet

Adults (Dermal Exposure Only); Vegetable Crops (6 lb ai/acre)

Vegetable / 

Groundboom

Screening Level

High Boom Very 

fine to Fine

6 0.2299

 

360 

 

720 

 

1,200 

 

1,900 

 

2,700 

 

3,300 

 

3,900 

 

4,800 

 

6,100 

 

8,300 

 

9,500 

Low Boom Very 

fine to Fine

 

780 

 

2,100 

 

3,300 

 

5,100 

 

6,700 

 

8,300 

 

9,500 

 

11,000 

 

13,000 

 

17,000 

 

22,000 

High Boom Fine to 

Medium / Coarse

 

1,400 

 

3,500 

 

5,100 

 

7,400 

 

9,500 

 

11,000 

 

13,000 

 

13,000 

 

17,000 

 

22,000 

 

22,000 

Low Boom Fine to 

Medium / Coarse

 

2,000 

 

5,600 

 

8,300 

 

11,000 

 

13,000 

 

17,000 

 

22,000 

 

22,000 

 

33,000 

 

33,000 

 

33,000 

Adults (Dermal Exposure Only); Vegetable Crops (SLN rate of 9 lb ai/acre)

Vegetable / 

Groundboom

Screening Level

High Boom Very 

fine to Fine

9 0.345

 

240 

 

480 

 

790 

 

1,300 

 

1,800 

 

2,200 

 

2,600 

 

3,200 

 

4,000 

 

5,600 

 

6,400 

Low Boom Very 

fine to Fine

 

520 

 

1,400 

 

2,200 

 

3,400 

 

4,400 

 

5,600 

 

6,400 

 

7,400 

 

8,900 

 

11,000 

 

15,000 

High Boom Fine to 

Medium / Coarse

 

910 

 

2,300 

 

3,400 

 

4,900 

 

6,400 

 

7,400 

 

8,900 

 

8,900 

 

11,000 

 

15,000 

 

15,000 

Low Boom Fine to 

Medium / Coarse

 

1,300 

 

3,700 

 

5,600 

 

7,400 

 

8,900 

 

11,000 

 

15,000 

 

15,000 

 

22,000 

 

22,000 

 

22,000 

Adults (Dermal Exposure Only); Golf Courses

Golf Course/ 

Groundboom

Screening Level

High Boom Very 

fine to Fine

12.5 0.479

 

170 

 

340 

 

570 

 

910 

 

1,300 

 

1,600 

 

1,900 

 

2,300 

 

2,900 

 

4,000 

 

4,600 

Low Boom Very 

fine to Fine

 

380 

 

1,000 

 

1,600 

 

2,500 

 

3,200 

 

4,000 

 

4,600 

 

5,300 

 

6,400 

 

8,000 

 

11,000 

High Boom Fine to 

Medium / Coarse

 

650 

 

1,700 

 

2,500 

 

3,600 

 

4,600 

 

5,300 

 

6,400 

 

6,400 

 

8,000 

 

11,000 

 

11,000 

Low Boom Fine to 

Medium / Coarse

 

970 

 

2,700 

 

4,000 

 

5,300 

 

6,400 

 

8,000 

 

11,000 

 

11,000 

 

16,000 

 

16,000 

 

16,000 

Children (1 to < 2 years old) (Dermal and Incidental Oral Exposure); Vegetable Crops (6 lb ai/acre)
Page 21 of 41

Vegetable / 

Groundboom

Screening Level

High Boom Very 

fine to Fine

6 0.2299

 

170 

 

350 

 

580 

 

930 

 

1,300 

 

1,600 

 

1,900 

 

2,300 

 

2,900 

 

4,100 

 

4,600 

Low Boom Very 

fine to Fine

 

380 

 

1,000 

 

1,600 

 

2,500 

 

3,200 

 

4,100 

 

4,600 

 

5,400 

 

6,500 

 

8,100 

 

11,000 

High Boom Fine to 

Medium/Coarse

 

660 

 

1,700 

 

2,500 

 

3,600 

 

4,600 

 

5,400 

 

6,500 

 

6,500 

 

8,100 

 

11,000 

 

11,000 

Low Boom Fine to 

Medium/Coarse

 

980 

 

2,700 

 

4,100 

 

5,400 

 

6,500 

 

8,100 

 

11,000 

 

11,000 

 

16,000 

 

16,000 

 

16,000 

Children (1 to < 2 years old) (Dermal and Incidental Oral Exposure); Vegetable Crops (SLN rate of 9 lb ai/acre)

Vegetable / 

Groundboom

Screening Level

High Boom Very 

fine to Fine

9

 

120 

 

230 

 

390 

 

620 

 

860 

 

1,100 

 

1,300 

 

1,500 

 

2,000 

 

2,700 

 

3,100 

Low Boom Very 

fine to Fine

 

250 

 

680 

 

1,100 

 

1,700 

 

2,200 

 

2,700 

 

3,100 

 

3,600 

 

4,300 

 

5,400 

 

7,200 

High Boom Fine to 

Medium/Coarse

 

440 

 

1,100 

 

1,700 

 

2,400 

 

3,100 

 

3,600 

 

4,300 

 

4,300 

 

5,400 

 

7,200 

 

7,200 

Low Boom Fine to 

Medium/Coarse

 

650 

 

1,800 

 

2,700 

 

3,600 

 

4,300 

 

5,400 

 

7,200 

 

7,200 

 

11,000 

 

11,000 

 

11,000 

Children (1 to < 2 years old) (Dermal and Incidental Oral Exposure); Golf Courses

Golf Course/ 

Groundboom

Screening Level

High Boom Very 

fine to Fine

12.5 0.479

 

83 

 

170 

 

280 

 

440 

 

620 

 

780 

 

920 

 

1,100 

 

1,400 

 

1,900 

 

2,200 

Low Boom Very 

fine to Fine

 

180 

 

490 

 

780 

 

1,200 

 

1,600 

 

1,900 

 

2,200 

 

2,600 

 

3,100 

 

3,900 

 

5,200 

High Boom Fine to 

Medium/Coarse

 

320 

 

820 

 

1,200 

 

1,700 

 

2,200 

 

2,600 

 

3,100 

 

3,100 

 

3,900 

 

5,200 

 

5,200 

Low Boom Fine to 

Medium/Coarse

 

470 

 

1,300 

 

1,900 

 

2,600 

 

3,100 

 

3,900 

 

5,200 

 

5,200 

 

7,800 

 

7,800 

 

7,800 

Bolded values are below the LOC of 1000.
Page 22 of 41

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 

March 2, 2010 (http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2009-0687-

0037). 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 bensulide.

The California Department of Pesticide Regulation (DPR) has released a draft report on its air 

monitoring network for public comment. In 2011, DPR established a monitoring network to 

sample ambient air for multiple pesticides in three communities on a regular basis. The draft 

report of results for the monitoring in 2014 is available at 

http://www.cdpr.ca.gov/docs/emon/airinit/air_network_results.htm. In the draft Air Monitoring 

Network Results for 2014 report, there were 0 detections of bensulide of 157 samples. 

Furthermore, in the 2012 and 2013 reports, there were 0 detections of bensulide. In the 2011 

report, there were 5 detects of bensulide of 142 samples; all detects were below the quantitation 

limit.

8.0 Occupational Exposure and Risk Estimates

Exposure to bensulide is assessed for handler scenarios; exposure to bensulide and bensulide 

oxon was assessed for post-application scenarios.

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 tractor application, 

 Mixing/loading liquids for chemigation and groundboom application,
Page 23 of 41

 Applying granules via tractor,

 Applying sprays via groundboom equipment, 

 Mixing/loading/applying liquids via handgun equipment, and

 Mixing/loading/applying granules via rotary spreader.

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: 

A summary of application rates is provided 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, 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 Table9”, 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 website10.

Area Treated or Amount Handled: 

Based on ExpoSAC Policy 9.1, the area treated or amount handled is assumed to be:

 40 acres for tractor or groundboom applications to golf courses, 

 350 acres for chemigation applications,

 80 acres for groundboom applications to typical field crops (vegetables),

 1000 gallons for handgun applications to field crops (vegetables), and

 5 acres for handgun/rotary spreader applications to golf courses.

Exposure Duration: 

For bensulide, based on the proposed use, steady-state exposure is expected.

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

calculated for various levels of personal protective equipment (PPE). Results are presented for 

the label-required PPE and also with various levels of additional PPE as necessary. A summary 

of PPE requirements in listed in Table 4.1.

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.

 

9 Available: http://www2.epa.gov/sites/production/files/2015-09/documents/handler-exposure-table-2015.pdf

10 Available: http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/occupational-pesticide-handlerexposure-data
Page 24 of 41

Combining Exposures/Risk Estimates:

A total aggregated risk index (ARI) was used since the LOC values for dermal exposure (1000) 

and inhalation exposure (3000) are different. The target ARI is 1; therefore, ARIs of less than 1 

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

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

Summary of Occupational Handler Non-Cancer Exposure and Risk Estimates

A summary of occupational handler risk estimates for bensulide with the label-required PPE is 

provided in Table 8.1.1 below. With the label-required PPE, all handler risk estimates are of 

concern (ARI < 1). A summary of handler risk estimates with additional PPE/ engineering 

controls to mitigate risks is provided in Table 8.1.2; most handler risk estimates are still of 

concern with the maximum PPE/ engineering controls. 
Page 25 of 41

Table 8.1.1. Occupational Handler Non-Cancer Exposure and Risk Estimates for Bensulide (with label-required PPE).

Exposure Scenario Crop or Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

Area 

Treated or 

Amount 

Handled 

Daily3

Dermal Inhalation Total

Dose 

(mg/kg/day)4

MOE5

(LOC = 

1000)

Dose 

(mg/kg/day)6

MOE7

(LOC = 

3000)

ARI8

Mixer/Loader

M/L, Granule, Tractor 

Application Golf Course DL/G: 3.4 PF 5: 0.34 16 lb ai/A 40 A 0.00316 1,900 0.00316 1,900 0.48

M/L, Liquid, Chemigation

Cucurbit/ Brassica/ 

Fruiting/ Dry bulb 

Vegetables 

SL/ G: 37.6 PF 5: 0.0438

6 lb ai/ A 350 A 0.114 53 0.00133 4,500 0.051

SLN Vegetables 9 lb ai/A 0.171 35 0.002 3,000 0.034

M/L, Liquid, Groundboom 

Application

Golf Course 12.5 lb ai/A 40 A 0.0272 220 0.000317 19,000 0.21

Cucurbit/ Brassica/ 

Fruiting/ Dry bulb 

Vegetables

6 lb ai/A 80 A 0.0261 230 0.000304 20,000 0.22

SLN Vegetables 9 lb ai/A 0.0393 150 0.000457 13,000 0.14

Applicator

Applying Sprays via 

Groundboom Equipment

Golf Course

SL/G: 16.1 PF 5: 0.068

12.5 lb ai/A 40 A 0.0117 510 0.000493 12,000 0.45

Cucurbit/ Brassica/ 

Fruiting/ Dry bulb 

Vegetables

6 lb ai/A 80 A 0.0112 540 0.000472 13,000 0.48

SLN Vegetables 9 lb ai/A 0.0168 360 0.00071 8,500 0.32

Applying Granule via 

Tractor Golf Course SL/G: 7.2 PF 5: 0.24 16 lb ai/A 40 A 0.00668 900 0.00223 2,700 0.45

Mixer/Loader/Applicator

M/L/A, Liquid, Handgun

Golf Course/ Lawn SL/ G: 880 PF 5: 0.38 12.5 lb ai/A 5 A 0.0797 75 0.000345 17,000 0.074

Field Crop SL/G: 390 PF 5: 0.78 0.16 lb 

ai/gal 1000 gal 0.0904 66 0.00181 3,300 0.062

L/A, Granule, Rotary 

Spreader

Lawn DL/G: 130 PF 5: 2 12.5 lb ai/A 5 A 0.0118 510 0.00181 3,300 0.35

Golf Course 16 lb ai/A 0.0151 400 0.00232 2,600 0.27

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (March 2013); Level of mitigation: SL/G =Single layer clothing and gloves; DL/G = Double layer clothing 

and gloves; PF 5 = respirator with protection factor of 5; PF 10 = respirator with protection factor of 10; EC = engineering controls.

2 Based on registered labels.

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 (%) ÷ BW (kg).

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

6 Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) × Conversion Factor (0.001 mg/μg) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A or gal/day) ÷ BW (kg).

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

8 ARI = Aggregate Risk Index = 1÷ [(Dermal LOC ÷ Dermal MOE) + (Inhalation LOC ÷ Inhalation MOE)].
Page 26 of 41

Table 8.1.2. Occupational Handler Non-Cancer Exposure and Risk Estimates for Bensulide (with additional level of PPE).

Exposure Scenario Crop or Target

Dermal Unit 

Exposure 

(μg/lb ai)1

Inhalation Unit 

Exposure 

(μg/lb ai)1

Maximum 

Application 

Rate2

Area Treated or 

Amount 

Handled Daily3

SL/G + PF 5 DL/G + PF 5 SL/G + PF 10 DL/G + PF 10 EC

ARI4

Mixer/Loader

M/L, Granule, Tractor 

Application Golf Course

SL/G: 6.9

DL/G: 3.4

EC: 8.6

PF 5: 0.34

PF 10: 0.17

EC: 0.083

16 lb ai/A 40 A 0.38 0.48

(current PPE) 0.54 0.76 0.58

M/L, Liquid, 

Chemigation

Cucurbit/ Brassica/ 

Fruiting/ Dry bulb 

Vegetables 

SL/ G: 37.6

DL/ G: 29.1

EC: 8.6

PF 5: 0.0438

PF 10: 0.0219

EC: 0.083

6 lb ai/ A

350 A

0.051

(current PPE) 0.065 0.052 0.066 0.18

SLN Vegetable 9 lb ai/A 0.034

(current PPE) 0.043 0.034 0.044 0.12

M/L, Liquid, 

Groundboom 

Application

Golf Course 12.5 lb ai/A 40 A 0.21

(current PPE) 0.27 0.22 0.27 0.75

Cucurbit/ Brassica/ 

Fruiting/ Dry bulb 

Vegetables

6 lb ai/A

80 A

0.22

(current PPE) 0.29 0.23 0.29 0.77

SLN Vegetables 9 lb ai/A 0.14

(current PPE) 0.19 0.15 0.2 0.52

Applicator

Applying Sprays via 

Groundboom 

Equipment

Golf Course

SL/G: 16.1

DL/ G: 12.6

EC: 5.1

PF 5: 0.068

PF 10: 0.034

EC: 0.043

12.5 lb ai/A 40 A 0.45

(current PPE) 0.57 0.48 0.61 1.3

Cucurbit/ Brassica/ 

Fruiting/ Dry bulb 

Vegetables

6 lb ai/A

200 A

0.48

(current PPE) 0.59 0.51 0.63 1.4

SLN Vegetables 9 lb ai/A 0.32

(current PPE) 0.4 0.34 0.43 0.88

Applying Granule via 

Tractor Golf Course

SL/G: 7.2

DL/ G: 4.2

EC: 2

PF 5: 0.24

PF 10: 0.12

EC: 0.22

16 lb ai/A 40 A 0.45

(current PPE) 0.56 0.6 0.82 0.74

Mixer/Loader/Applicator

M/L/A, Liquid, Handgun

Golf Course/ Lawn SL/ G: 880

DL/G: 450

PF 5: 0.38

PF 10: 0.19 12.5 lb ai/A 5 A 0.074

(current PPE) 0.15 0.075 0.15 NA

Field Crop SL/G: 390

DL/G: 290

PF 5: 0.78

PF 10: 0.39 0.16 lb ai/gal 1000 gal 0.062

(current PPE) 0.082 0.064 0.086 NA

L/A, Granule, Rotary 

Spreader

Lawn SL/G: 240

DL/G: 130

PF 5: 2

PF 10: 1

12.5 lb ai/A

5 A

0.22 0.35

(current PPE) 0.25 0.41 NA

Golf Course 16 lb ai/A 0.18 0.27

(current PPE) 0.2 0.33 NA

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (March 2013); Level of mitigation: SL/G =Single layer clothing and gloves; DL/G = Double layer clothing 

and gloves; PF 5 = respirator with protection factor of 5; PF 10 = respirator with protection factor of 10; EC = engineering controls.

2 Based on registered labels.

3 Exposure Science Advisory Council Policy #9.1.
Page 27 of 41

4 ARI = Aggregate Risk Index = 1÷ [(Dermal LOC ÷ Dermal MOE) + (Inhalation LOC ÷ Inhalation MOE)].
Page 28 of 41

8.2 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.

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.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2009-0687-0037). 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 bensulide.

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.

8.2.2 Occupational Post-application Dermal Exposure/Risk Estimates

Bensulide is registered for use on golf course turf and on vegetable crops. A dermal postapplication assessment has been conducted for the golf course turf use. However, since 

bensulide is applied to vegetables as a preplant or preemergence application only, occupational 

post-application dermal exposures are not anticipated for these uses. There is a low potential for 

occupational post-application exposure when pre-emergent herbicides are used. Bensulide is 

applied to the soil directly and is soil incorporated well before the crops are mature. The timing 

of the application of bensulide can greatly reduce the potential for post-application exposure. 

Minimal exposure during harvesting or any other late season activities is expected since

bensulide is applied pre-emergent. Therefore, HED does not require a post-application 

occupational exposure assessment (HED Exposure Science Advisory Council Policy No. 008).

Occupational Post-application Dermal Exposure Data and Assumptions
Page 29 of 41

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

post-application risk assessments for the golf course use. Each assumption and factor is detailed 

below on an individual basis.

Exposure Duration: 

For bensulide, an exposure profile consistent with steady-state exposure is expected.

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 311” which, along with 

additional information about the ARTF data, can be found at the Agency website12. Table 

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

coefficients for the proposed crops/use sites.

Table 8.2.2.1. Anticipated Post-Application Activities and Dermal Transfer Coefficients.

Proposed Crops

Policy Crop 

Group 

Category

Crop 

Height

Foliage 

Density

Transfer 

Coefficients 

(cm2/hr)

Activities

Golf Course Turf Low Full 3700 Maintenance

Application Rate:

Application rates are listed in Table 4.1. 

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

Turf Transferable Residues: Chemical-specific TTR data are available for the liquid formulation 

of bensulide. See Section 6.2 for a description of the TTR data. The data include measurements 

on bensulide and the oxon. Due to the differences in the dissipation of bensulide and the oxon, 

residues of the oxon were adjusted by the toxicity adjustment factor (TAF; oxon residue, ug/cm2

* 50X TAF), and total residues (bensulide + adjusted oxon) were used to determine the risk 

resulting from exposures following bensulide applications. Since no data are available for the 

granular formulation, the liquid formulation residue data were used as a surrogate. As noted 

above, this is considered a health protective approach since, in general, granular formulations 

tend to result in lower percent transfer from turf than do liquid formulations (e.g., the 2012 

Residential SOP turf default percent transfer factor is 1% for liquids and 0.2% for granulars).

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

 

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

12 Available: http://www.epa.gov/pesticides/science/post-app-exposure-data.html
Page 30 of 41

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

Occupational post-application risks were estimated for workers; risk estimates were of concern 

until 5 days after treatment (DAT 5). See Tables 8.2.2.2 (for liquid formulations) and 8.2.2.3

(for granular formulations) below for a summary of the occupational post-application risk 

estimates.

Table 8.2.2.2. Occupational Post-application Non-Cancer Exposure and Risk Estimates for Bensulide + Oxon (with 50X 

TAF) (Liquid Formulations).

Crop/Site Activities Transfer Coefficient 

(cm2/hr)

DAT

TTR1 Dermal Dose 

(mg/kg/day)2 MOE3

Golf Course Maintenance 3700

0 0.475 0.0204 290

1 0.351 0.0151 400

2 0.259 0.0111 540

3 0.192 0.0082 730

4 0.141 0.0061 990

5 0.105 0.00448 1,300

1 TTR = Data from MRID 44799001. Total TTR, ug/cm2 = [ (oxon residue, ug/cm2) * 50 X TAF] + [bensulide residue, ug/cm2)

2 Daily Dermal Dose = [DFR (μg/cm2) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption (10%)]  BW (69 kg).

3 MOE = POD (6 mg/kg/day) / Daily Dermal Dose. 

Table 8.2.2.3. Occupational Post-application Non-Cancer Exposure and Risk Estimates for Bensulide + Oxon (with 50X 

TAF) (Solid Formulations).

Crop/Site Activities Transfer Coefficient 

(cm2/hr)

DAT

TTR1 Dermal Dose 

(mg/kg/day)2 MOE3

Golf Course Maintenance 3700

0 0.6083 0.026097 230

1 0.4493 0.019276 310

2 0.3319 0.014238 420

3 0.2452 0.010517 570

4 0.181 0.00777 770

5 0.134 0.00574 1,000

1 TTR = Default assumption that 0.2% of application rate available as TTR on day 0. Dissipation rate and oxon conversion data from MRID 

44799001. Total TTR, ug/cm2 = [ (oxon residue, ug/cm2) * 50 X TAF] + [bensulide residue, ug/cm2)

2 Daily Dermal Dose = [DFR (μg/cm2) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption (10%)]  BW (69 kg).

3 MOE = POD (6 mg/kg/day) / Daily Dermal Dose. 

Restricted Entry Interval

Bensulide is classified as Toxicity Category III via the dermal route, Toxicity Category IV for 

dermal irritation, and Toxicity Category III for eye irritation. It is not a skin sensitizer. Under 

40 CFR 156.208 (c) (2), ai’s classified as Acute III or IV for acute dermal, eye irritation and 

primary skin irritation are assigned a 12-hour REI. However, steady-state post-application risk 

estimates were a concern up to Day 5 for golf course maintenance activities. Therefore, HED is 

recommending that the REI be revised on the label to address those concerns.
Page 31 of 41

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

Residential Non-cancer Handler Algorithms

Dermal and Inhalation Handler Exposure Algorithm

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

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

handled in a day, using the equation below:

E = UE * AR * A

where:

E = exposure (mg/day);

UE = unit exposure (mg/lb ai);

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

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

Residential Handler Dose Algorithm

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

D = E *AF / BW

where:

D = dose (mg/kg-day);

E = exposure (mg/day);

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

BW = body weight (kg).

Residential Non-cancer Post-application Algorithms

Post-application Dermal Exposure Algorithm – Physical Activities on Turf

Exposure resulting from contacting previously treated turf while performing physical activities is 

calculated as shown below. Residential post-application exposure assessment must include 

calculation of exposure on the day of application. Therefore, though an assessment can present 

exposures for any day “t” following the application, it must include “day 0” exposure.

E = TTRt * CF1 * TC * ET

where:
Page 32 of 41

E = exposure (mg/day);

TTRt = turf transferable residue on day t (μg/cm2);

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

TC = transfer coefficient (cm2/hr); and

ET = exposure time (hr/day).

If chemical-specific TTR data are available, then surface residues from the day of application 

should be used (assume that individuals could be exposed to residues immediately after 

application). However, if data are not available, then TTRt can be calculated using the following 

formula:

TTRt= AR * F * (1-FD)t * CF2 * CF3

where:

TTRt = turf transferable residue on day t (μg/cm2);

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

F = fraction of ai as transferable residue following application (unitless);

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

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

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

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

Dermal absorbed doses are calculated as:

BW

E AF D*



where:

D = dose (mg/kg-day);

E = exposure (mg/day);

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A-1: Turf (Physical Activities) -- Inputs for Residential Post-application Dermal Exposure

Algorithm Notation Exposure Factor

(units) Point Estimate(s)

AR Application rate

(mass active ingredient per unit area) 12.5 lb ai/acre

F

Fraction of AR as TTR 

following application (if 

chemical-specific data is 

unavailable)

L/WP/WDG 0.01

Granules 0.002

FD

Daily residue dissipation 

(if chemical-specific data 

is unavailable)

(fraction)

L/WP/WDG 0.1

Granules 0.1

TC L/WP/WDG Adults 180,000
Page 33 of 41

Table A-1: Turf (Physical Activities) -- Inputs for Residential Post-application Dermal Exposure

Algorithm Notation Exposure Factor

(units) Point Estimate(s)

Transfer 

Coefficient 

(cm2/hr)

Children 1 < 2 years old 49,000

Granules

Adults 200,000

Children 1 < 2 years old 54,000

ET Exposure Time

(hours per day)

Adults 1.5

Children 1 < 2 years old 1.5

BW Body Weight

(kg)

Adults 80

Children 1 < 2 years old 11

L/WP/WDG = Liquids/Wettable Powders/Water-dispersible Granules

Post-application Hand-to-Mouth Exposure Algorithm– Physical Activities on Turf

Exposure from hand-to-mouth activity is calculated as follows (based on the algorithm utilized in 

the SHEDS-Multimedia model):

E = [HR * (FM * SAH) * (ET * N_Replen) * (1- (1- SE)

(Freq_HtM/N-Replen))]

where:

E = exposure (mg/day);

HR = hand residue loading (mg/cm2);

FM = fraction hand surface area mouthed / event (fraction/event);

SAH = typical surface area of one hand (cm2);

ET = exposure time (hr/day);

N_Replen = number of replenishment intervals per hour (intervals/hour);

SE = saliva extraction factor (i.e., mouthing removal efficiency); and

Freq_HtM = number of hand-to-mouth contacts events per hour (events/hour).

and

SA * 2

Fai *DE

HR

H

hands



where:

HR = hand residue loading (mg/cm2);

Faihands = fraction ai on hands compared to total surface residue from dermal transfer coefficient 

study (unitless);

DE = dermal exposure (mg); and

SAH = typical surface area of one hand (cm2).

Dose, normalized to body weight, is calculated as:

BW

E

D 
Page 34 of 41

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-2: Turf (Physical Activities) – Inputs for Residential Post-application Hand-to-Mouth 

Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

Faihands

Fraction of ai on hands 

from dermal transfer 

coefficient study

(unitless)

Liquid formulations 0.06

Granular formulations 0.027

DE Dermal exposure (mg) Calculated

SAH

Typical surface area of one hand (cm2), children 1 < 

2 years old 150

AR Application rate

(mass active ingredient per unit area) 12.5 lb ai/acre

HR Residue available on the hands (mg/cm2) Calculated via (DE * Faihands)/SAH

FM

Fraction hand surface area mouthed

(fraction/event) 0.127

N_Replen Replenishment intervals per hour

(intervals/hr) 4

ET Exposure time 

(hrs/day) 1.5

SE Saliva extraction factor

(unitless) 0.48

Freq_HtM Hand-to-mouth events per hour

(events/hr) 13.9

BW Body Weight

(kg)

Children 1 < 2 years 

old 11

Post-application Object-to-Mouth Exposure Algorithm– Physical Activities on Turf

Exposure from object-to-mouth activity is calculated as follows (based on the algorithm utilized 

in SHEDS-Multimedia):

E = [OR* CF1 * SAMO * (ET * N_Replen) * (1- (1- SEO)

(Freq_OtM/N_Replen))]

where:

E = exposure (mg/day);

OR = chemical residue loading on the object on day “t” (ug/cm2);

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

SAMO = area of the object surface that is mouthed (cm2/event);

ET = exposure time (hr/day);

N_Replen = number of replenishment intervals per hour (intervals/hour);

SEO = saliva extraction factor (i.e., mouthing removal efficiency); and

Freq_OtM = number of object-to-mouth contact events per hour (events/hour).
Page 35 of 41

and

OR = AR * FO * CF2 * CF3

where:

OR = chemical residue loading on the object (μg/cm2);

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

FO = fraction of residue available on the object (unitless);

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

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

Dose, normalized to body weight, is calculated as:

BW

E

D 

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-3: Turf (Physical Activities) – Inputs for Residential Post-application Object-to-Mouth 

Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

AR Application rate (to turf)

(mass active ingredient per unit area) 12.5 lb ai/acre

FO Fraction of AR as OR following application 1 0.01

SAMO

Surface area of object mouthed 

(cm2/event) 10

N_Replen Replenishment intervals per hour (intervals/hour) 4

SEO

Saliva extraction factor

(fraction) 0.48

ET Exposure time 

(hours per day) 1.5

Freq_OtM Object-to-mouth events per hour (events/hr) 8.8

BW Body Weight (kg) Children 1 < 2 years old 11

1 This SOP assumes that all of the residue on the turf could be transferred to the object (e.g., object residue is 

equal to turf transferable residue).

Post-application Incidental Soil Ingestion Exposure Algorithm– Physical Activities on Turf

Exposure from incidental soil ingestion is calculated as follows:

E = SRt * SIgR * CF1

where:

E = exposure (mg/day);
Page 36 of 41

SRt = soil residue on day "t" (μg/g);

SIgR = ingestion rate of soil (mg/day); and

CF1 = weight unit conversion factor (1 x 10-6g/μg).

and

SRt = AR * FS * (1-FD)

t

* CF2 * CF3 * CF4

where:

SRt = soil residue on day "t" (μg/g);

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

FS = fraction of ai available in uppermost cm of soil (fraction/cm);

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

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

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

CF3 = area unit conversion factor (1.08 x 10-3ft2/cm2 or 2.47 x 10-8acre/cm2); and

CF4 = soil volume to weight unit conversion factor (0.67 cm3/g soil).

Dose, normalized to body weight, are calculated as:

BW

E

D 

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-4: Turf (Physical Activities) – Inputs for Residential Post-application Incidental Soil Ingestion 

Exposure 

Algorithm 

Notation

Exposure Factor

(units) Point Estimate(s)

AR Application rate

(mass active ingredient per unit area) 12.5 lb ai/acre

FS Fraction of AR available in uppermost 1 cm of soil

(unitless) 1

FD

Daily residue dissipation

(fraction) 0.1

SIgR Soil ingestion rate (mg/day) 50

BW Body weight (kg) Children 1 < 2 years old 11

Post-application Episodic Granular Ingestion Exposure Algorithm– Physical Activities on Turf

Exposure from incidental ingestion of pesticide pellets or granules is calculated as follows:

 E = GIgR* FD * CF1
Page 37 of 41

where:

E = exposure (mg/day);

GIgR = ingestion rate of dry pesticide formulation (g/day);

FD = fraction of ai in dry formulation (unitless); and

CF1 = weight unit conversion factor (1,000 mg/g).

Dose, normalized to body weight, are calculated as:

BW

E

D 

where:

D = dose (mg/kg-day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A-5: Turf (Physical Activities) – Inputs for Residential Post-application Episodic Granular 

Ingestion Exposure 

Algorithm 

Notation

Exposure Factor 

(units) Point Estimate(s)

FD Fraction of active ingredient in dry formulation 12.5%

AR Application rate (lbs/A or lbs/1,000 ft2) 12.5 lb ai/acre

GIgR Granule ingestion rate per day

(g/day) 1 0.3

BW Body Weight (kg) Children 1 < 2 years old 11

1 See discussion below on how this value may be adjusted if product specific information is available.

Post-application Dermal Exposure Algorithm – Mowing

Exposure resulting from contacting previously treated turf while mowing is calculated as 

follows:

E = TTRt * CF1 * TC * ET

where:

E = exposure (mg/day);

TTRt = turf transferable residue on day "t" (μg/cm2);

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

TC = transfer coefficient (cm2/hr); and

ET = exposure time (hr/day).

and

TTRt = AR * FAR * (1-FD)

t

* CF2 * CF3

where:
Page 38 of 41

TTRt = turf transferable residue on day "t" (μg/cm2);

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

FAR = fraction of ai retained on turf (unitless);

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

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

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

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

Absorbed dose, normalized to body weight, are calculated as:

BW

E AF D*



where:

D = dose (mg/kg-day);

E = exposure (mg/day); 

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A-6: Turf (Mowing) – Inputs for Residential Post-application Dermal Exposure 

Algorithm Notation Exposure Factor

(units) Point Estimate(s)

AR Application rate

mass active ingredient per unit area 12.5 lb ai/acre

FAR

Fraction of AR as 

TTR following 

application

L/WP/WDG 0.01

Granules 0.002

FD

Daily residue 

dissipation

L/WP/WDG 0.1

Granules 0.1

TC Transfer Coefficient

(cm2/hr)

Adult 5,500

Children 11 < 16 years 

old 4,500

ET Exposure time 

(hours per day) 1

BW Body Weight 

(kg)

Adults 80

Children 11 < 16 years 

old 57

L/WP/WDG = liquid/wettable powder/water dispersible granule

Post-application Dermal Exposure Algorithm – Golfing

Exposure resulting from contacting previously treated turf while golfing is calculated as follows:

E = TTRt * CF1 * TC * ET

where:
Page 39 of 41

E = exposure (mg/day); 

TTRt = turf transferable residue on day "t" (μg/cm2);

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

TC = transfer coefficient (cm2/hr); and

ET = exposure time (hr/day).

and

TTRt = AR * F * (1-FD)

t

* CF2 * CF3

where:

TTRt = turf transferable residue on day "t" (μg/cm2);

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

F = fraction of ai retained on turf (unitless);’

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

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

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

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

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

BW

E AF D*



where:

D = dose (mg/kg-day);

E = exposure (mg/day); 

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A-7: Turf (Golfing) – Inputs for Residential Post-application Dermal Exposure 

Algorithm 

Notation

Exposure Factor

(units)

Point Estimate(s)

AR Application rate

(mass active ingredient per unit area)

12.5 lb ai/acre

F Fraction of AR as TTR 

following application

L/WP/WDG 0.01

Granules 0.002

FD Daily residue dissipation L/WP/WDG 0.1

Granules 0.1

TC Transfer Coefficient

(cm2/hr)

Adult 5,300

Children 11 < 16 years old 4,400

Children 6 < 11 years old 2,900

ET Exposure time

(hours per day)

Pesticides used on greens, tees, 

and fairways 

4

Pesticides used only on greens 

and tees

1

BW Body Weight

(kg)

Adults 80

Children 11 < 16 years old 57

Children 6 < 11 years old 32
Page 40 of 41

NA = not applicable

L/WP/WDG = liquid/wettable powder/water dispersible granule

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 41 of 41

Occupational Non-cancer Post-application Algorithms

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

following formulas:

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:

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).