### UNITED ST A TES ENV IRO NMENT AL PROTECTION AGENCY
WASHINGTON, D.C. 20460



### OFFICE OF CHEMICAL SAFETY AND POLLUTION PRE VENT ION

MEMORAN D UM

Date: 15 Se ptemb er 2015



### SUBJECT : C hlorimuron 

### Ethyl. Draft Human H ea lth Risk Asstssment in Support of R egistrat i on Re view

.



### FROM :

THROUGH:

TO: PC Code : 1 2890 I Decision No.: 502175 Petition No.: NA 

### Risk Assessment Type: 

### Single Chemical 

### Aggregate TXR 

### No .: NA 

### MRID No.: 

### None DP 

### Barcode: 04 26094 Registration No.: NA 

### Regu l atory Act i on: 

### Regi s tration Review Case No.: 7403

CAS No. : 90982-32-4 40 CFR: 180.429



### Mic h ael A. Doherty

, Ph.D., Chemist

,, 

# crv
Karlyn Middleton, M.S.

, Toxicologist Zaida Figueroa, DrPH

, Industrial Hygienist Risk Assessment Branch II Health Effects Division (7509P) ·

Christina Swartz, Branch Chief

# ~**~** Risk Assessment Branch II Health Effects Divi sion (7509 P)

Wilhemena Livingston

, Chemical R eview Manager Kevin Costello, Branch Chief Ri sk Management and Implem e ntation Branch IV (RM lB IV ) Pesticide Re-Evaluation Division (7508P)

As part of r eg i stration review, HED h as examined the toxicologica l and expos ure d atabases for

a s sessing human health risks associated with chlorimuro n et hyl and conducted a n ew risk

assessmen t following current practices a nd policies. S ignificant changes relative to the last risk

a s sessment (D358796

, W. Cutc hin

, 14 Sept. 2009) include:

• E stablishment of e ndp oints and point s of departure for assessing acute diet ary exposure , dermal exposure for child r en, and incidental oral exposure for children;

• Assessment of acute dietary risk for all population group s; and

• Assessment of spray drift risk for adults and c hildr e n

.
Page 1o f 46

### 1.0


### 2.0 2.1 2.2 

## 3.0
3. 1 3.2 3.3


### 4.0 4.1 

### 4.2 4. 3 4.4 

## 5.0
5.1 5.2 5

. 3 

### Table of Contents

Executive Summary

.... ..... ............ ..... .... . ......................... . .. . ..... ... ..... ...... ... . ........... . . ..... . ..... 3
HED Recommendations

.... . ........ .. .... . .... .. ............................................... .. . .... ... ..... .. .......... 4
T o l e ran ce Considerat i o n s

.. ....... .. .... . ... .. ... ... .. .. .. ... ... ...... ... ... . .. ... ..... . ...... .... ..... ... .... .. ....... .. 4 Label Co n s ider at ion s

. .. .. ....... .. .... . .................................................................................... 5


### Introduction

............................................ ............ ................. .. .. ... . . ...................................... 5 C h em i ca l I den tit y and Ph ysica l / C h emical Charac teri s tic s

.. ..... .. ...... .. ..... ..... ... . ........ . ....... 5 P es ticid e Use P atte rn a nd A nti c ipat ed Exposure Pathway s

... . ........................ . ............... . 

### 5 Conside r at i o n of E n vironmenta l Ju st i ce

....... .. ............. ... ...... . .. .. .. ..... ...... . ........................ 6


### Hazard Identification/Toxicology

... ... ....... ... ....... . ........ . . ...... .......... ...... .............. ... ........... . 7 Su mm ary of Toxico l ogical Effects

................ .. ... . ... ... .. ...... .. ...... ...... .. .... .... ... ..... ..... .... ..... 7 Safety Fa c t or for I nfants and Chi ldr e n (F QP A Safety F a cto r)

..... .... ...... .. ..... .. ........ . ........ 

### 8 Toxicity E ndpoint and Point of Departure Selections

...................................................... 

### 9
E ndocrine Disruptor Screening Pro gram

....................................................................... 11 

### Dietary Exposure and Risk Assessment

........... . ......... . ........ . ...... . ... . ............. . ..... . ........... 12
Wate r R esidue Profile

........... .. . . .... ... ........ . .... ... ....... .. ....... .. ..... .. ...... . ...... . ....................... 1 2 Foo d R esi du e Pr o fil e

..... . .... ... ...... ... .... ...... ... ... ........ . ....... .. ... .. ...... ...... ........... .. . . ...... .. .... . . 1 3 Dietary Expos ur e and Risk Estimates

................ . ........................................................... 13


### 6.0 Re s idential (Non-Occupationa l ) Exposure/Risk Characterization

............................. 14 6.1 S pra y Drift

.. . .... .. ....................... ... ..... ...... .. ... ........ . ..... . .. . .... ..... ... ..... ..... ...... . .... ... . . ..... .. .... 14 

### 6. 1. l Combined Risk Estimates from La wn D e p ositio n Adjace nt to App li cat i o n s

.............. 14 6

. 2 R es id e ntial Bystander Po st-A pplication Inh a l ation Ex po s ur e

....................................... 1 5


### 7.0 Aggregate Exposure/Risk Characterization

..................................................... . ............ 16
8.0 Cumulative Exposure / Risk Characterization

............................................................... 16
9

. 0 Occupational Exposure/Risk Characterization

............................................................ 16 9.1 Occupational H andler Exposure / Risk Est im ates

........................................................ . ... 16 9.2 Occupational P ost -applic at ion Ex po s ure / Ri sk Estimates

...... . .......... .. ............ . .............. 19 9.2 .1 Occupational P os t- app li ca tion Inh a l ation Exposure / Risk Est i mates

.. .... ... . .. .. . ........... . 20 

### 9.2.2 O ccupa ti ona l P ost

- ap pli ca tion Dermal Exposure/Ri s k Es timat es

............................... 

### 20
10

. 0 Public Health and Pesticide E pidemiology Data

...................................................... .. ... 22
11.0 Literature Reference s

........... ...... ..... .. ......... ......... ... ..... ..... .......... ....... .. ............................ 23
12.0 References

... .... ...................... ......... .. ............. ............ .......... ... ... .. .. ......... ......... . ......... . .... ... 23 Appendix A. Appendix B. Appendix C. 

### Appendix D. Appendix E. Appendix F. Toxicology Data Requirements and Toxicology Profile

................................ 24 Revie\v of Human Research

... ... ........... ..... ... ...................................... ... ....... . ... 29 Occupational Non-cancer Algorithms

. ...... ... ................................................... 29 Dietary Exposure/Risk Modeling Input and Output

..................................... 31
Nomenclature and Physical/Chemical Propertie s

........ ... ...... . ..... ........... .... .... 44 Spray Drift Detailed De sc ription

..................................................................... 45

Pa ge 2o f 46

### Page 3 of 46

1 .0 Executive Summary

Chlorimuron ethyl { ethyl 2

- [[[[(4

- chloro

- 6

- methoxy

- 2

- pyrimidinyl)amino]carbonyl]amino]

- sulfonyl]benzoate } is a herbicide of the sulf on ylurea class

. Its mode of action is through inhibition of the plant enzyme acetolactate synthase, which is also known as acetohydroxy acid synthase

. Inhibition of this enzyme blocks branch ed

- chain amino acid biosynthesis of valine, leucine, and isoleucine (involved in plant growth) processes and leads to death of the plant. Chlorimuron ethyl is registered for use on soybeans, field corn, peanuts, low growing berries (subgroup 13

- 07H, except strawberry) and non

- crop areas such as fence rows and roadsides 

### for the control of broadleaf weeds and grass es

.

The last human health risk assessment for chlorimuron ethyl was completed in 200 9 ( D 370361

, W. Cutchin )

. A human health scoping document was conducted for chlorimuron ethyl in 201 0 ( D 379636 , D. McNeilly ) . Identified data needs include d a cute and subchronic neurotoxicity studies in the rat, an immunotoxicity study, a 21

- or 28

- day dermal toxicity study in the rat or rabbit

, and a rat 90

- day subchronic inhalation study



### . At this time, all of the required studies have been submitted or waiv ed

, and both the toxicology and exposure database s for chlorimuron ethyl are considered complete and adequate for risk assessment

. This draft risk assessment incorporates all new data and includes updates to hazard and exposure assessments, science policie s , and procedures

.

For dieta ry exposure, HED has conducted screening

- level acute and chronic dietary risk
assessment s for chlorimuron ethyl using tolerance

- level residues in foods and a sulfonylurea

class

- wide screening

- level estimate of residues in dri nking water

. Dietary risk estimates range from 3 to 13% (acute) and from 8 to 30% (chronic) of the population adjusted dose s ( PAD s ) and are below HED’s level of concern (LOC)

.

There are no registered residential uses or uses resulting in direct residential exposure associated with chlorimuron ethyl

. Therefo re, a quantitative residential exposure assessment was not performed

. However, chlorimuron ethyl can be applied via groundboom and aerial equipment and, therefore, there is the potential for in direct exposure to chlorimuron ethyl as a result of spray drift

. Based on this, HED estimated risks associated with spray drift. The resulting ris k estimates are not of concern ( margin s of exposure (MOE s) ≥ 23 ,000 with a level of concern (LOC) of 100)

. Due to the lack of uses in a residential setting , aggregate exposure and risk estimates are equivalent to the dietary exposure and risk estimates and do not exceed HED’s level of concern.

No chemical

- specific handler exposure data were submitted in suppor t of this draft risk
assessment ; therefore, HED relied on the best available data to assess handler exposure

. Default assumptions established by HED ’s Science Advisory Council for Exposure (ExpoSAC) were used for parameters such as body weight and amount h andled

. All occupational handler scenarios for the registered uses resulted in MOEs ranging from 860 to 1,900,000. As these are greater than the LOC of 100 at risk mitigation ranging from baseline attire ( with no gloves or respirator )
to engineering control s ( for aerial applications such as enclosed cockpits) they reflect risk estimates that are not of concern

.

### Page 4 of 46

Based on the Agency's current practices, a quantitative non

- cancer occupational post

- application inhalation exposure assessme nt was not performed for chlorimuron ethyl

. If new policies or procedures are put into place, the Agency may revisit the need for such an assessment

.

The restricted entry interval ( REI ) of 12 hours specified on the registered labels is based on the

acu te toxicity of chlorimuron ethyl and is adequate to protect agricultural workers from post

application exposures

.

HED has no t identified any risk concerns associated with the registered uses of chlorimuron ethyl

. There are no data gaps that would require su bmission of additional toxicity , residue chemistry, or exposure data.

2.0 HED Recommendations

2.1 Tolerance Considerations

The existing tolerances (40 CFR 180. 429 ) are supported by the available residue chemistry data

. At this time, there is a Canadian MRL for residues of chlorimuron ethyl in soybeans at 0.05 ppm; there are no other Canadian MRLs and no Codex MRLs for chlorimuron ethyl . The U.S. tolerance for residues of chlorimuron ethyl in soybean, seed is 0.05 ppm and is harmonized with the Canadian MRL. No revisions to the existing U.S. tolerances are needed during registration review.

An analytical reference standard for chlorimuron ethyl is currently available in EPA’s National Pesticide Standards Repository (NPSR) and has an expirat ion date of 22 January 2019 (email communication between G. Verdin and J. Van Alstine, 5/11/2015)

. The registrant is required to maintain reasonable amounts of the reference standards for chlorimuron ethyl in the NPSR as long as tolerances remain published in 40 CFR §180.429

. When necessary, new reference standards, or updated certificates of analysis (COAs), should be sent to the Analytical Chemistry Branch (ACB), which is located at Fort Meade, MD

. It should be sent to the attention of either Theresa Cole or Thuy Nguyen at the address listed below, along with a letter of transmittal

. Please note that the full 9

- digit ZIP Code is required, or the mail will be returned to the registrant

.

USEPA

National Pesticide Standards Repository Analytical Chemistry Branch/BEAD/OPP 701 Mapes Road Fort George G. Meade, MD 20755

- 5350

The letter of transmittal sho uld include the assay of the standard, name of the analytical method used, a statement of principal impurities, purification procedures employed, storage requirements, and special precautions for safe handling

. Replacement of standards, or updated COAs, ma y be required periodically if supplies are exhausted, if the standards expire, or if decomposition occurs during storage

. Safety Data Sheets (SDSs) must accompany all analytical

### Page 5 of 46

standards as specified by the Occupational Safety and Health Administration (O SHA) in 29CFR §1910.1200

.

2.2 La bel C onsiderations

The current labels for chlorimuron don’t require enclosed cockpits for aerial applications; HED recommends that PRD ensure that the registered labels state the need of enclosed cockpits for aerial equipment.

3.0 Introduction

3.1 Chemical Identity and Physical/Chemical Characteristics

Chlorimuron ethyl { ethyl 2

- [[[[(4

- chloro

- 6

- methoxy

- 2

- pyrimidinyl)amino]carbonyl]amino]

- sulfonyl]benzoate } is a systemic herbicide belonging to the pyrimidinylsulfonylurea class of chemicals

. The chemical properties of chlorimuron ethyl do not suggest that there are any particular exposure issues that warrant special consideration

. The compound has a dissociation
constant of 4.2 at 25°C , making its wa ter solubility dependent on pH, with low solubility below pH 3

. The potential for chlorimuron ethyl to partition into fatty matrices is also, by extension, pH dependent; however, based on the octanol/water partitioning coefficients, such partitioning is

un likely to occur at physiological pH levels

. Chlorimuron ethyl has a relatively low vapor
pressure , indicating that inhalation of vapors is unlikely to be a significant source of exposure under ambient conditions

. The nomenclature and physical/chemical prop erties of chlorimuron ethyl are provided in Appendix E

.

3.2 Pesticide Use Pattern and Anticipated Exposure Pathways

Chlorimuron ethyl is registered for use on soybeans, field corn, peanuts, low growing berries (subgroup 13

- 07H, except strawberry) and non

- crop areas such as fence rows and roadsides



### . There

are 22 registered end

- use product s , all of which are forms of dry

- flowable formulations

. The registered application methods for chlorimuron ethyl include the use of aerial and ground equipment.

The re gistered use pattern s allows one or two application per season ; therefore , the duration of
exposure for occupational handlers is expected to be short

- term ( i.e

. , 1 to 30 days) and i ntermediate

- term ( i.e., 1 to 6 months) ; long

- term exposures (greater than 6 months) are not anticipated

. The PPE statement s on registered labels require applicators, flaggers and other handlers to wear the following : long sleeved shirt, long pants, shoes plus socks, and chemical

resistant gloves

. The restricted entry interval (REI) on all labels is 12 hours.

Exposure Pathways

Individuals may be exposed to chlorimuron ethyl via their diet (food and drinking water)

. There are no registered uses for chlorimuron ethyl that will result in direct non

- dietary (i.e., residential)
exp osures

. However, there is the potential for indirect exposure (incidental oral and dermal) to

### Page 6 of 46

chlorimuron ethyl related to spray drift

. Agricultural workers may be exposed to chlorimuron ethyl during mixing, loading, and/or applying the herbicide (dermal a nd inhalation routes) as well as during post

- application activities (dermal route)

.

Table 3.2

. Summary of Directions for Registered Use s of Chlorimuron ethyl

. Applic. Timing, Type, and Equip. Formulation and

Products [EPA Reg No.] Applic.

Rate (lb ai/A) Max. No. Applic. per Season Max.

Seasonal Applic. Rate (lb ai/A) Use Directions and Limitations

Field Corn Ground band or broadcast, aerial 25% a.i. (DG)

[352

- 436] 0.005

- 0.063 2 0.063 Product may be applied crop pre

plant, pre

- and post

- emergence, and post

- harvest as a burn down. Application interval = 7 days Pre

- harvest interval = 7 days Cranberry Ground broadcast

, aerial 25% a.i. (DG)

[ WA100004 ] 0.016 1 0.016 Product may be applied early post weed emergence Pre

- harvest interval = 60 days Only for use in the state of Washington Peanut Ground band or broadcast, aerial 25% a.i. (DG)

[352

- 436]

25% a.i. (DG) [ 71368

- 82 ] 0.0 078 1 0.0078 Product may be applied 60 days after crop emergence to 45 days before harvest. Pre

- harvest interval = 45 days

Soybean Ground band or broadcast, aerial 279

- 3179, 279

- 3184,

352

- 436, 352

- 444, 352

- 573, 352

- 574

, 352

- 589, 352

- 596 , 352

- 599, 352

- 635, 352

- 648, 352

- 650, 352

- 749, 352

- 756, 352

- 757, 59639

- 116, 59639

- 117, 71368

- 8 2, 71368

- 83

, 71368

- 8 4 and 85588

- 5 (% ai varies from 8.3

– 31.8% in products) 0.0 0 47

- 0.063 2 0.063 Apply after the first trifoliate has opened, but not later than 60 days before maturity.

Application interval = 2

- 3 weeks Pre

- harvest interval = Do not app ly later than the flowering stage Do not graze treated fields or harvest for forage or hay.

Non

- crop land (fence rows, roadsides, equipment storage, and similar areas) Ground band or broadcast, aerial 25% a.i. (DG)

[352

- 436]

25% a.i. (DG) [ 71368

- 82 ] 0.016

- 0.031 2 0.063 Apply to weeds, post

- emergent



### 3.3 Consideration of Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, were considered in the preliminary human health risk assessment for chlorimuron ethyl , in accordance with U.S. Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority

### Page 7 of 46

Populations and Low

- Income Populations

. " 1 

### As a part of every pesticide risk assessment, OPP considers a large variety of consumer subgroups accor ding to well

- established procedures

. In line with OPP policy, HED estimates risks to population subgroups from pesticide exposures that are based on patterns of that subgroup’s food and water consumption, and activities in and around the home that involve pesticide use in a residential setting

. Extensive data on food consumption patterns are compiled by the USDA under the National Health and Nutrition Examination Surveys/What We Eat in America (NHANES/WWEIA) and are used in pesticide risk assessments for al l registered food uses of a pesticide

. These data are analyzed and categorized by subgroups based on age and ethnic group

. Additionally, OPP is able to assess dietary exposure to smaller, specialized subgroups and exposure assessments are performed when co nditions or circumstances warrant

. Whenever appropriate, non

- dietary exposures based on home use of pesticide products and associated risks for adult applicators and for toddlers, youths, and adults entering or playing on treated areas post

- application are evaluated

. Further considerations are currently in development as OPP has committed resources and expertise to the development of specialized software and models that consider exposure to bystanders and farm workers as well as lifestyle and traditional di etary patterns among specific subgroups

.

4.0 Hazard Identification/Toxicology

The toxicology database for chlorimuron ethyl is complete and adequate for risk assessment

. Immunotoxicity and inhalation studies are not available for chlorimuron ethyl , as required in accordance with the current Part 158 Guidelines (40 CFR Part 158)

. However, t he Hazard and Science Policy Council (HASPOC) determined that the subchronic inhalation (TXR# 0056401) and immunotoxicity studies are not required for chlorimuron ethyl

. The immunotoxicity requirement has been waived for the entire sulfonylurea class of chemicals ( TXR#0056723)

. Since the last risk assessment ( D358796

, D. McNeilly, 14 September 2009 ), new acute and subchronic neurotoxicity and dermal toxicity studie s have been submitted

. The toxicological endpoints and points of departure (PODs) have been updated based on the new toxicology data

, and new acute dietary and incidental oral risk assessments have been conducted

. Also, the dermal risk assessment has been revised, and a separate children’s dermal risk assessm ent has been conducted since the adult dermal assessment is based on a developmental endpoint (not appropriate for children’s exposure)

. All other endpoints/PODs selected for risk assessment remain the same as in previous assessments

. See Appendix A for the chlorimuron ethyl toxicological profile.

4.1 Summary of Toxicological Effects

A variety of effects were seen after oral exposure to chlorimuron ethyl

. After subchronic exposure, decreased body wei ght/body weight gain and liver effects (increased weights and margination of hepatocyte cytoplasmic content) were observed in rats

. After chronic exposure, effects in the rat were limited to decreased body weight and body weight gain; no liver effects

were observed

. In dogs, hematological changes (decreased erythrocyte count, hematocrit, and hemoglobin concentration) were primarily seen after both subchronic and chronic exposure

. Increased liver weights and atrophy of the thymus and prostate were also obser ved in dogs after

1 http://www.epa.gov/compliance/resources/policies/ej/exec_order_12898.pdf

### Page 8 of 46

subchronic exposure

. However, these effects were not seen in chronic dog studies

. No treatment

related effects were seen in mice after subchronic or chronic exposure

. There was no evidence of carcinogenicity observed in the mouse or rat carcinogenicity studies

. In addition, there was no indication of mutagenicity in the battery of available studies.

No treatment related effects were observed after dermal exposure to chlorimuron ethyl at doses up to the limit dose

. C linical signs were o bserved in acute and subchronic neurotoxicity studies

. In the acute study, reduced arousal and reduced motor activity were seen in male and female rats at the mid and high dose

. At the high dose , males preferred a curled up posture compared to controls and there was an increased incidence of palpebral closure

. In the subchronic neurotoxicity study, effects observed were decreased body weight/body weight gain and reduced food consumption in females at the high dose

. No treatment

- related neurotoxic effects we re observed in the study.

Increased quantitative susceptibility of the young was observed in rabbit developmental and rat reproduction toxicity studies

. In the rabbit developmental study, delayed ossification was seen in fetuses in the absence of mater nal toxicity

. In the rat reproduction study, decreased body weight and histopathology in the cerebellum (cellular changes in the internal granular and external germinal layers) were seen in pups in the absence of maternal toxicity

. The changes observed in the cerebellum were not associated with neurotoxicity or neurobehavioral changes, and not observed in other rat reproduction studies available for chlorimuron at similar doses

. Additionally, there was no evidence of increased susceptibility observed in the other reproduction studies

. In acute lethality studies, chlorimuron ethyl has low or minimal acute toxicity via the oral (category IV), dermal (category III), and inhalation routes of exposure (category IV)

. It is mildly irritating to the eye (category III) and non

- irritating to the skin (category IV); it is not a skin sensitizer.

Chlorimuron ethyl is well absorbed from the gastrointestinal tract, extensively metabolized and excreted approximately equally between the urine and feces

. Unchanged parent co mpound was identified, primarily in the urine

. In the feces at 24 hrs post

- dosing, less than 10% of the radioactivity was identified as the parent compound

. Radioactivity was distributed throughout the body, with the highest levels observed in the liver, a nd a half

- life of 50 hrs; retention of radioactivity in tissues was insignificant by 168 hrs post

- dosing

.

4.2 Safe ty Factor for Infants and Children (FQPA Safety Factor)

HED recommends that the FQPA S afety F actor be reduced to 1 x for chlorimuron ethyl

. The toxicology database is complete, and there no concerns/ residual uncertainties with regard to pre

and/or postnatal toxicity , and no concern for neurotoxicity

. Although increased quantitative susceptibility was seen in the rabbit developmental and rat reproduction studies, the fetal effect seen in rabbits was limited to delayed ossification and increased susceptibility was not seen in a rat developmental study

. The effects observed in the rat reproduction study (histopathology in the cerebellum) were no t reproduced in two other rat reproduction studies at similar doses

. Additionally, there are clear NOAELs for the fetal/offspring effects seen in the studies

.

### Page 9 of 46

Furthermore, the endpoints and points of departure selected for risk assessment are protective of the effects observed in the studies

.

4.3 Toxicity Endpoint and Point of Departure Selections

The toxicological endpoints and points of departure (PODs) used for risk assessment have been updated considering new toxicology data which includes a dermal toxicity study, as well as acute and subchronic neurotoxicity studies

. An acute dietary risk assessment has been conducted since treatment related effects were noted in the new acute neurotoxicity study

. An endpoint/POD for incidental oral exposure has also been selected for use in a spray drift assessment

. No treatment related effects were seen in the new dermal toxicity study at doses up to the limit dose

. However, increased susceptibility was seen in developmental and reproduction studies

. Therefore, the developmental rabbit, with the lowest point of departure, was used for adult dermal risk assessment to protect for potential sensitivity. The endpoint (delayed ossification) observed in fetuses in the developmental rabbit study is not relevant for asse ssing kids dermal risk

. Therefore, the reproduction study (with a higher POD) was used for assessing children’s dermal risk

. All other endpoints/PODs selected for risk assessment remain the same as in previous
assessments

. It should be noted that the endpo ints and points of departure (POD) presented in the toxicology profile table (appendix X) have not been updated to comply with current policy

. The NOAELs and LOAELS have not been changed

. Therefore, the endpoints/PODs selected for risk assessment may be co nservative

. The PODs selected for risk assessment are protective of the effects observed in the chlorimuron toxicology database

. A summary of toxicological doses and endpoints used in the chlorimuron ethyl human health risk assessments is presented below:

Table 4.3. 1

. Toxicological Doses and Endpoints for Chlorimuron ethyl for Use in Dietary and Non

- Occupational

Human Health Risk Assessments. Exposure/ Scenario Point of

Departure Uncertainty/

FQPA Safety Factors RfD, PAD,

Level of Concern for Risk Assessment Study and Toxicological Effects

Acute Dietary (All populations) NOAEL =

100 mg/kg/day UF A = 10X

UF H = 10X FQPA SF = 1X Acute RfD =1

mg/kg/day

aPAD = 1 mg/kg/day Acute Neurotoxicity

- Rat, LOAEL=500

mg/kg/day, based on reduced arousal and reduced motor activity in male and female rats

Incidental oral (short

- term) NOAEL =

9.0 mg/kg/day UF A = 10X

UF H = 10X FQPA SF = 1X Residential

LOC for MOE = 100 Co

- critical studies

90

- day oral toxicity

– dogs LOAEL = 42.7 mg/kg/day, based on hematological changes (increased hematocrit, hemoglobin, erythrocyte counts) atrophy of the thymus and prostate, increased absolute and relative liver weights.

Chronic toxicity

– dogs LOAEL = 50 mg/kg/day, based on mild anemia.

### Page 10 of 46

Table 4.3. 1

. Toxicological Doses and Endpoints for Chlorimuron ethyl for Use in Dietary and Non

- Occupational

Human Health Risk Assessments. Exposure/ Scenario Point of

Departure Uncertainty/

FQPA Safety Factors RfD, PAD,

Level of Concern for Risk Assessment Study and Toxicological Effects

Children’s Dermal Short

- (1

- 30 days) and Intermediate

term (1

- 6 months) Offspring

NOAEL = 17/21mg/kg/d
ay

* DAF=4.8% UF A = 10X

UF H = 10X FQPA SF = 1X Residential

LOC for MOE = 100 2 generation reproduction

- rats

Offspring LOAEL

- Rat = 177/214 mg/kg/day, based on reduced pup weight i n both generations (up to 20%) and histopathological findings in the cerebellum (cellular changes in the internal granular and external germinal layers)

. Effects observed in the absence of maternal effects. Chronic Dietary (All Populations) NOAEL = 9

mg/kg/day UF A = 10X

UF H = 10X FQPA SF = 1X Chronic RfD =

0.09 mg/kg/day

cPAD = 0.09 mg/kg/day Co

- critical studies

90

- day oral toxicity

– dogs LOAEL = 42.7 mg/kg/day, based on hematological changes (increased hematocrit, hemoglobin, erythrocyte counts) atrophy of the thymus and prostate, increased absolute and relative liver weights.

Chronic toxicity

– dogs LOAEL = 50 mg/kg/day, based on mild anemia. Cancer (oral, dermal, inhalation) “Not Likely to be Carcinogenic to Humans.”

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 leve l

. LOAEL = lowest observed adverse effect level

. UF = uncertainty factor

. UFA = extrapolation from animal to human (interspecies)

. UFH = potential variation in sensitivity among members of the human population (intraspecies)

. UFL = use of a LOAEL to extrapolate a NOAEL

. UFS = use of a short

- term study for long

- term risk assessment

. UFDB = to account for the absence of key data (i.e., lack of a critical study)

. FQPA SF = FQPA Safety Factor

. PAD = population adjusted dose (a = acute, c = chronic)

. RfD = reference dose

. MOE = margin of exposure

. LOC = level of concern

. N/A = not applicable. * Dermal absorption factor based on a comparison between the dermal toxicity and the oral rabbit developmental toxicity studies using a ratio of the oral LOAEL and derm al NOAEL [i.e., (48/1000)*100].

Table 4.3. 2. Summary of Toxicological Doses and Endpoints for Chlorimuron ethyl for Use in Occupational

Human Health Risk Assessments. Exposure/ Scenario Point of

Departure Uncertainty

Factors Level of

Concern for Risk Assessment Study and Toxicological Effects

Adult Dermal (1

- 30 days) and Intermediate

- term (1

- 6 months) Development

al NOAEL = 13 mg/kg/day

DAF=4.8% UF A = 10X

UF H = 10X FQPA SF = 1X Occupational

LOC for MOE = 100 Developmental Toxicity

- Rabbit

Developmental LOAEL = 48 mg/kg/day, based on delayed ossification in fetuses in the absence of maternal effects.

### Page 11 of 46

Table 4.3. 2. Summary of Toxicological Doses and Endpoints for Chlorimuron ethyl for Use in Occupational

Human Health Risk Assessments. Exposure/ Scenario Point of

Departure Uncertainty

Factors Level of

Concern for Risk Assessment Study and Toxicological Effects

Inhalation Short

- (1

- 30 days) and Intermediate

- term (1

- 6 months) NOAEL = 9.0

mg/kg/day UF A = 10X

UF H = 10X FQPA SF = 1X Occupational

LOC for MOE = 100 Co

- critical studies

90

- day oral toxicity

– dogs LOAEL = 42.7 mg/kg/day, based on hematological changes (increased hematocrit, hemoglobin, erythrocyte counts) atrophy of the thymus and prostate, increased absolute and relative liver weigh ts.

Chronic toxicity

– dogs LOAEL = 50 mg/kg/day, based on mild anemia. Cancer (oral, dermal, inhalation) “Not Likely to be Carcinogenic to Humans.”

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 f actor

. UFA = extrapolation from animal to human (interspecies)

. UFH = potential variation in sensitivity among members of the human population (intraspecies)

. UFL = use of a LOAEL to extrapolate a NOAEL

. UFS = use of a short

- term study for long

- term risk a ssessment

. UFDB = to account for the absence of key data (i.e., lack of a critical study)

. FQPA SF = FQPA Safety Factor

. PAD = population adjusted dose (a = acute, c = chronic)

. RfD = reference dose

. MOE = margin of exposure

. LOC = level of concern

. N/A = not applicable.



### 4.4 Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse outcomes from exposure to chemicals

. Collectively, these studies include acute, subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include endpoints which may be susceptible to endocrine influence, including effects on endocrine target organ h istopathology, organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring

. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, developmenta l and reproductive effects in different taxonomic groups

. As part of its most recent registration decision for chlorimuron ethyl

, EPA reviewed these data and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing haz ard database

. However, as required by FFDCA section 408(p ), chlorimuron ethyl is subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP).

EPA has developed the EDSP to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” The EDSP employs a two

- tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems

. chemicals that go th rough Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA

### Page 12 of 46

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endocrine

- related effects caused by the substance, and establish a dose

- response relationship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemic als

. Between October 2009 and February 2010, EPA issued test orders/data call

- ins for the first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients

. A second list of che micals identified for EDSP screening was publ ished on June 14, 2013 2 

### and includes some pesticides

s che duled for Registration Review and che micals found in water

. For further information on the status of the EDSP, the policies and procedures, the list s of che micals, future lists, the test guidelines a nd the Tier 1 screening battery, please visit our website. 3



### 5.0 Dietary Exposure and Risk Assessment

5.1 Water Residue Profile

Screening groundwater

- sourced drinking water exposure estimates were generated with the Pesticide Root Zone Model for GroundW ater ( PRZM

- GW; v.1.07) for use in the sulfonylurea (SU) dietary risk assessments

. Rather than produce chemical

- specific estimated drinking water concentrations (EDWCs) following the usual assessment procedures, EFED provided coarse

screen estimates that sh ould exceed upper

- bound, chemical

- specific EDWCs for any SU

. This was achieved by using model inputs that represent the use pattern of highest exposure from any SU, the highest soil mobility of any SU residue of concern, and the highest persistence to any route of degradation over time

. The resulting coarse

- screen EDWCs from PRZM

- GW were used as conservative estimates of exposure and are summarized in Table 5.1 ( D427429, G. Orrick )

. The acute and chronic dietary assessments for chlorimuron ethyl used the coarse

- screen maximum daily concentration of 751 μg/L (0.751 ppm) and the post

- breakthrough mean value of 492 μg/L (0.492 ppm), respectively

.

Table 5.1. PRZM

- GW Coarse

- Screen EDWCs for Sulfonylureas 1

.

Modeled Scenario K d or K OC Initial Application Dates (days post

emergence) Max. Daily Conc.

(μg/L) Mean

Breakthrough Time (yrs) Post

breakthrough Mean (μg/L)

WI corn K d 7 449 11.5 415

K OC 7 504 6.9 425
DMV corn K d 7 489 5.3 369

K OC 7 560 3.3 378
FL citrus K d 7 429 3.2 351

K OC 7 467 2.3 349 FL potato K d 7 375 2.6 272

2 See http://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPPT

- 2009

- 0477

- 0074 for the final second list of chemicals.

3 http://www.epa.gov/endo/

### Page 13 of 46

Table 5.1. PRZM

- GW Coarse

- Screen EDWCs for Sulfonylureas 1

.

Modeled Scenario K d or K OC Initial Application Dates (days post

emergence) Max. Daily Conc.

(μg/L) Mean

Breakthrough Time (yrs) Post

breakthrough Mean (μg/L)
K OC 7 407 2.2 275 GA peanut K d 7 197 5.2 156

K OC 7 206 3.9 158
NC cotton K d 7 640 8.7 492

K d 37 641 8.7 491
K d 67 637 8.7 490
K OC 7 742 5.7 484
K OC 37 751 5.7 483
K OC 67 744 5.7 482

1 Maximum values are bold ed.



### 5.2 Food Residue Profile

Chlorimuron ethyl is registered for use on , and tolerances have been established for residues of chlorimuron ethyl in or on, corn (grain at 0.01 ppm)

, low

- growing berry except strawberry (crop subgroup 13

- 07H at 0.02 ppm) , peanut (0.02 ppm) , and soybean (seed at 0.05 ppm). In conducting this assessment, HED has assumed tolerance

- level residues in those raw agricultural commodities and processed products

, and that 100 percent of those crops are treated with chlorimuron ethyl

.

5.3 Dietary Exposure and Risk Estimates

Exposure and risk estimates were obtained from the Dietary Exposure Evaluation Model using the Food Commodity Intake Database (DEEM

- FCID; version 3.18)

. The model uses food consumption data from the 2003

- 2 008 NHANES/WWEIA database, coupled with recipe files and residues in foods, to derive estimates of dietary exposure and risk

. Generally, HED is concerned when dietary exposure estimates exceed 100% of the population adjusted dose (PAD)

. In the case of chlo rimuron ethyl , the dietary risk estimates (Table 5.3) are below HED’s level of concern, ranging from 2 to 4% of the acute PAD ( aPAD ) and from 3 to 1 0 % of the chronic PAD ( cPAD )

. Because of the very conservative assumptions used in the analysis (tolerance l evel residues, 100 % crop treated, upper

- bound modeled drinking water estimates), actual exposure and risk are expected to be much lower than those shown in Table 5 .3

. The listings of inputs and outputs to the assessment are included in Appendix D

.

Table 5 .3

. Summary of dietary exposure and risk estimates for chlorimuron ethyl

. Acute Estimates (95 th 

### Percentile) Chronic Estimates

Population Group Exposure, mg/kg bw Risk, % aPAD Exposure, mg/kg bw/day Risk, % cPAD Total US Population 0.0410 4 0.0103 12 

### All Infants (< 1 year old) 0.128 13 0.0267 30 

### Children 1

- 2 years old 0.0633 6 0.0150 17 

### Children 3

- 5 years old 0.0513 5 0.0126 14

### Page 14 of 46

Table 5 .3

. Summary of dietary exposure and risk estimates for chlorimuron ethyl

. Acute Estimates (95 th 

### Percentile) Chronic Estimates

Population Group Exposure, mg/kg bw Risk, % aPAD Exposure, mg/kg bw/day Risk, % cPAD Children 6

- 1 2 years old 0.0391 4 0.00910 10 

### Youth 13

- 19 years old 0.0342 3 0.00756 8 

### Adults 20

- 49 years old 0.0404 4 0.0103 12 

### Adults 50

- 99 years old 0.0360 4 0.0102 11 

### Female 13

- 49 years old 0.0409 4 0.0103 11



### 6.0 Residential (Non

- Occupational) Exposure/Risk Characterization

There are no registered residential uses or occupational uses resulting in residential exposure associated with chlorimuron ethyl

. Therefo re, a quantitative residential exposure assessment was not performed.

6.1 Spray Drift

A detailed description about HED’s spray drift policy and how to evaluate the drift potential and associated risks is available in Appendix F.

6.1. 1 Combined Risk Estimates from Lawn Deposition Adjacent to Applications

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

r esult of the screening level agricultural application scenarios

. 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 product s

. Chlorimuron ethyl is used

on a variety of agricultural crops including soybeans, field corn, peanuts, and low growing berries (subgroup 13

- 07H, except strawberry)

. It is also used in non

- crop areas such as fence rows and roadsides and can be applied via ground and aerial equipment

. Soybean is the predominant agricultural usage, and therefore, it is considered representative of the registered

uses

. 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 to medium 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).

• Airblast applications are based on the AgDrift option for Sparse (Young/Dormant) tree canopies.

T he spray drift a ssessment is based on dermal and incidental oral exposures

. The highest exposure resulted from drift following chlorimuron applications using aerial equipment for children 1 to <2 years old (margin s of exposure (MOEs) ≥ 23 ,000

, with a LOC = 100)

. There are no risks of concern at the field’s edge (i.e., assuming a residential lawn is directly adjacent to a

### Page 15 of 46

field where agricultural crops are grown and treated with aerial, groundboom or airblast equipment)

. See Tables 6.1.1 and 6.1.2 for detaile d results.

1 HED’s default assumption that 10% of the application is available for transfer on day 0 following the application and the residues dissipate at a rate of 10% each following day.

1 HED’s default assumption that 10% of the application is available for transfer on day 0 following the application and the residues dissipate at a rate of 10% each following day.



### 6.2 Residential Bystander Post

- Application Inhalation Exposure

Volatilization of pesticides may be a source of post

- application inhalation exposure to individuals nearby pesticide applications

. The agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fun gicide, 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

. 4 

### During Registration Review, the agency will use this analysis to determine if data (i.e., flux studies, route

- specific inhalation toxicological studies) or further analys e s are required for chlorimuron ethyl

.

4 Available at: http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

- OPP

- 2014

- 0219

. Table 6.1.1. Adult Risk Estimates (MOEs) Related to Dermal Exposure to Spray Drift from Chlorimuron ethyl. Crop/Rate Group Spray Type/ Nozzle Configuration Appl. Rate (lb ai/A) TTR 1 (ug/cm 2 ) At Edge of the Field

Aerial Fine to Medium 0.0 8 0.008892 30,000 Groundboom High Boom Very fine to Fine 42,000 Airblast Sparse 54,000

Table 6.1.2

. Children (1<2 years old) Risk Estimates (MOEs) Related to Derma l and Indirect Exposure to Spray Drift

from Chlorimuron. Crop/Rate Group Spray Type/ Nozzle Configuration Appl. Rate (lb ai/A) TTR 1 (ug/cm 2 ) At Edge of the Field

Dermal Aerial Fine to Medium 0.0 8 0.008892 23,000 Groundboom High Boom Very fine to Fine 32,000 Airblast Sparse 42,000 Incidental Oral (Hand

- to

- Mouth) Aerial Fine to Medium 0.0 8 0.008892 29,000 Groundboom High Boom Very fine to Fine 0.0 8 0.008892 40,000 Airblast Sparse 51,000

### Page 16 of 46

7.0 Aggregate Exposure/Risk Characterization

The Food Quality Protection Act of 1996 directs EPA to assess aggregate exposure to pesticide chemical residues, including all anticipated dietary exposures and all other exposures for which there is reliable information

. In the case of chlorimuron ethyl , aggregate exposure and risk estimates are equivalent to the dietary exposure and risk estimates in Section 5, above, and are below HED’s level of concern.

8.0 Cumulative Exposure/Risk Characterization

In 2015, EPA’s Office of Pesticide Programs released a guidance document entitled, Pesticide Cumulative Risk Assessment: Framework for Screening Analysis [http://www.epa.gov/oppfead1/cb/csb_page/updates/2015/framework

- for

- s creening

analysis.html]. This document provides guidance on how to screen groups of pesticides for cumulative evaluation using a two

- step approach beginning with the evaluation of available toxicological information and if necessary, followed by a risk

- ba sed screening approach. This framework supplements the existing guidance documents for establishing common mechanism groups (CMGs) 5 

### and conducting cumulative risk assessments (CRA) 6



### . The Agency has utilized this framework to evaluate the SUs of which orthosulfamuron is a member (J. D’Agostino; D428798; 9/9/15). Although the SUs share some chemical and toxicological characteristics, the toxicological database does not support a testab le hypothesis for a common mechanism of action. No further mechanistic data are required and no further cumulative evaluation is necessary.

9.0 Occupational Exposure/Risk Characterization

9.1 Occupational Handler Exposure/Risk Estimates

Based on curr ent labeling, types of equipment and techniques that can potentially be used, occupational handler exposure is expected from the registered uses

. The quantitative
exposure /risk assessment developed for occupational handlers is based on the scenarios listed in Table 9.1

. Based on the use pattern (i.e., 1

- 2 applications per crop depending on rate) and agricultural practices, occupational exposure from the registered food uses is expected to be short

- term (1

- 30 days) and intermediate

- term (i.e., 1

- 6 months) in duration

. Since the same endpoint and point of departure were selected for short

- and intermediate

- term durations, short

term exposure and risk estimates are considered to be protective of intermediate

- term exposure and risk

. Long

- term exposures (i.e., mo re than 6 months) are not anticipated.

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.

5 Guidance For Identifying Pesticide Chemicals and Other Substances that have a Common Mechanism of Toxicity (USEPA, 1999)

6 Guidance on Cumulative Risk Assessment of Pesticide Chemicals That Have a Common Mechanism of Toxicity (USEPA, 2002)

### Page 17 of 46

Application Rate : The maximum single application rates are listed in Table 3.2

. Refer to section 3.0 for a complete use pattern description.

Body Weight: The standard body weight for the general population (80 kg) was used for all inhalation exposure scenarios covered in this risk assessment because the endpoint selected was not developmental and/or based on fetal effects

. However, since the dermal PODs is based on developmental and/or fetal effects, the body weight appropriate for dermal assessments is 69 kg

. Absorption Factor : Since no inhalation absorption data are available, toxicity by the inhalation route is conside red to be equivalent to the estimated toxicity by the oral route of exposure

. A n upper bound dermal absorption factor of 4.8 % was determined for the exposure assessment based on a comparison between the dermal toxicity and the oral rabbit developmental tox icity studies using a rati o of the oral LOAEL and dermal N OAEL [i.e., (48/1000)*100].

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 absen ce of chemical

- specific data, include PHED 1.1, and the AHETF database

. 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 th at are used in this assessment, known as “unit exposures”, are outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table 7



### . ” HED policy on use of surrogate data, including descriptions of the various sources, can be found at t he Agency website 8



### .

Area Treated or Amount Handled: The inputs for area treated or amount handled were based on the Science Advisory Council for Exposure Policy 9.1: Standard Values for Daily Acres Treated in Agriculture (values are listed in Table 9.1)

. The acres treated for high acreage crops and orchard/vineyards were used as screening for the occupational assessment.

Risk Estimate Equations : The algorithms used to estimate non

- cancer exposure and dose for occupational handlers can be found in Appen dix C.

Summary of Occupational Handler Non

- Cancer Exposure and Risk Estimate

The exposure scenarios presented in Table 9.1 are considered protective of all existing uses

. All occupational handler scenarios for the registered uses resulted in MOEs greater than 100 at baseline level of risk mitigation (i.e., baseline attire with no gloves or respirator) or engineering control for aerial applications (i.e., enclosed cockpits) and, therefore, are not of concern

. The lowest MOE is 860 associated with dermal ex posure during mixing/loading activities for a dispersible granule formulation being applied aerially over up to 1,200 acres 9



### . All other MOEs were significantly higher, ranging from 2,300 to 1,900,000

. The current labels for chlorimuron

7 Available: http://www.epa.gov/opp00001/sci ence/handler

- exposure

- table.pdf

8 Available: http://www.epa.gov/pesticides/science/handler

- exposure

- data.html

9 The MOE of 860 is based on an application rate of 0.08 lb ai/A which was identified during the initial phase of registration review; however, that rate does not appear on any currently registered labels for chlorimuron ethyl.

### Page 18 of 46

don’t require enclos ed cockpits for aerial applications; therefore, PRD should ensure that the registered labels state the need of enclosed cockpits for aerial equipment.

The Agency matches quantitative occupational exposure assessment with appropriate characterization of exp osure potential

. While HED presents quantitative risk estimates for human flaggers where appropriate, agricultural aviation has changed dramatically over the past two decades

. According the 2012 National Agricultural Aviation Association (NAAA) survey of
t heir membership, the use of Global Positioning System ( GPS ) technology 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 a gricultural aerial a pplications.

HED has no data to assess exposures to pilots using open cockpits

. The only data available reflects exposure to pilots in enclosed cockpits

. Therefore, risks to pilots are assessed using the engineering control ( i.e., enclosed cockpits) and baseline attire ( i.e., 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 lev el of protection, there are no risk estimates of concern for applicators.

Table 9.1

. Short

- term Handler Exposure and Risk Estimates for Chlorimuron. Exposure Scenario Dermal

Unit Exposure (ug/lb ai) [Mitigation Level] ab Inhalation

Unit Exposure (ug/lb ai) [Mitigation Level] ab Application

Rate c Area

Treated or Amount Handled d Dermal

Dose e (mg/kg/day ) Dermal

MOE f Inhalation Dose g (mg/kg/day) Inhalation

MOE h

Mixer/Loader Dry Flowable ( D ispersible Granule) for Aerial Application 227 8.96 0.063 lb ai/A 1,200 A 0.012 1,000 0.00846 1,100

0.080 lb ai/A 0.015 860 0.0108 830

Dry Flowable ( D ispersible Granule) for Groundboom Application 227 8.96 0.063 lb ai/A 200 A 0.00199 6,500 0.00141 6,400

0.080 lb ai/A 0.00253 5,100 0.00179 5,000

Dry Flowable ( D ispersible Granule) for Airblast Application 227 8.96 0.063 lb ai/A 40 A 0.000398 33,000 0.000283 32,000

Applicator Sprays for Aerial Application 2.08

[Engineeri
ng Controls

– Enclosed Cockpit] 0.0049

[Engineering Controls

– Enclosed Cockpit] 0.063 lb

ai/A 1,200 A 0.000109 120,000 0.00000463 1,900,000

0.080 lb ai/A 0.000139 94,000 0.00000588 1,500,000

Sprays for Groundboom Application 78.6 0.34 0.063 lb ai/A 200 A 0.000689 19,000 0.0000535 170,000

0.080 lb ai/A 0.000877 15,000 0.0000680 130,000

### Page 19 of 46

Table 9.1

. Short

- term Handler Exposure and Risk Estimates for Chlorimuron. Exposure Scenario Dermal

Unit Exposure (ug/lb ai) [Mitigation Level] ab Inhalation

Unit Exposure (ug/lb ai) [Mitigation Level] ab Application

Rate c Area

Treated or Amount Handled d Dermal

Dose e (mg/kg/day ) Dermal

MOE f Inhalation Dose g (mg/kg/day) Inhalation

MOE h

Sprays for Airblast Application 1,770 4.71 0.063 lb ai/A 40 A 0.0031 4,200 0.0001490 60,000

Flagger Sprays for Aerial Application 11 0.35 0.063 lb ai/A 350 A 0.000169 77,000 0.0000965 93,000

0.080 lb ai/A 0.000214 61,000 0.000123 73,000

Mixer/Loader/Applicator

M/L/A Dry Flowable ( D ispersible Granule) for Mechanically

p ressurized Handgun 1,300 3.9 0.0063 lb ai/gal 1,000 gal 0.0057 2,300 0.000308 29,000

M/L/A Dry Flowable ( D ispersible Granule) for Backpack Sprayer 8,260 2.58 0.0063 lb ai/gal 40 gal 0.00145 9,000 0.00000813 1,100,000

M/L/A Dry Flowable ( D ispersible Granule) for Manually

pressurized Handwand 29,000 1,100 0.0063 lb ai/gal 40 gal 0.00509 2,600 0.00346 2,600

a. Mitigation Level: “ baseline ” (i.e., single layer of clothing consisting of a long sleeved shirt, long pants, shoes plus socks, no gloves, and no respirator ); “ engineering controls for aerial applications ” (i.e., enclosed cockpit). b. Based on the “ Occupational Pesticide Handler Unit Exposur e Surrogate Reference Table ” (February, 2015). c. Based on the maximum single application rates listed on registered labels (Table 3.2). A maximum rate of 0.08 lb ai/A was identified during the scoping phase of registration review, but that rate is not on any currently registered labels; it may be from a petitioned

- for use that was not registered. d. Based on the Science Advisory Council for Exposure Policy 9.1: Standard Values for Daily Acres Treated in Agriculture

. e. Dermal Dose (mg/kg/day) = [Rate x UE x 0.0001 x Dermal Absorption (4.8%) x Acres Treated or Amount Handled]/BW (69 kg) . f. Dermal MOE = Dermal NOAEL (mg/kg/day)/ Dermal Dose (mg/kg/day) . LOC=100. g. Inhalation Dose (mg/kg/day) = [Rate x UE x 0.0001 x Acres Treated or Amount Handled]/BW (80 k g)

. h. Inhalation MOE = Inhalation NOAEL (mg/kg/day)/ Inhalation Dose (mg/kg/day) . LOC=100.



### 9.2 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 re

entry 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 proper ties

. In addition, the timing of pesticide applications, relative to harvest activities, can greatly reduce the potential for post

- application exposure.

### Page 20 of 46

9.2.1 Occupational Post

- application Inhalation Exposure/Risk Estimates

There are multiple potential s ources 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 pesti cides

. 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/#!docketDetai l;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 chlorimuron

. In addition, the Agenc y 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
occup ational post

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

Although a quantitative occupational post

- application inhalation exposure assessment was not performed, an inhalation exposure assessment was performed for occupational handl ers

. Handler exposure resulting from application of pesticides outdoors is likely to result in higher exposure than post

- application exposure

. Therefore, it is expected that these handler inhalation exposure estimates would be protective of most occupation al post

- application inhalation exposure scenarios.

9.2.2 Occupational Post

- application Dermal Exposure/Risk Estimates

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

- application dermal risk assessment , including the following:

Exposure Duration: Based on the use pattern and agricultural practices, occupational post

application exposure from the registered food uses is expected to be short

- term (1

- 30 days) and intermediate

- term (i.e., 1

- 6 months) in duration

. Since the same endpoint and point of departure were selected for short

- and intermediate

- term durations, short

- term exposure and risk estimates are considered to be protective of intermediate

- term exposure and risk

. Long

- term exposures (i.e., more than 6 months) are not anticipated.

Transfer Coefficients: It is the policy of HED to use the best available data to assess post

application exposure

. Sources of generic post

- application data, used as surrogate data in the absence of chemical

- specific data, are derived from Agricultural Re

- entry Tas k Force ( ARTF ) exposure monitoring studies, and, as proprietary data, are subject to the data protection provisions of FIFRA

. The standard values recommended for use in predicting post

- application exposure that are used in this assessment, known as “transf er coefficients”, are presented in the

### Page 21 of 46

ExpoSAC Policy 3 10 

### ” which, along with additional information about the ARTF data, can be found at the Agency website 11



### . Table 9.2.2.1 provides a summary of the anticipated post

application activities and associated transfer coefficients for the proposed crops/use sites.

Table 9.2.2.1

. Anticipated High

- contact Post

- Application Activities and Dermal Transfer Coefficients.

Proposed Crop s Policy Crop Group Category Crop

Height Foliage

Density Transfer

Coefficients (cm 2 /hr ) Activities

Corn, sweet, grain, processing Field, row, tall High Full 1,900 Irrigation (Hand set)

Corn, sweet, grain Field, row, tall High Full 8,800 Hand, Detasseling

Cranberry Berry, low Low Full 1,100 Scouting

Peanuts Field, row,

low

- medium Low Full 1,900 Irrigation (Hand set)

Soybean Field, row,

low

- medium Low Full 1,100 Scouting



### Application Rate : The maximum single application rates are listed in Table 3.2

. Refer to section 3.0 for a complete use pattern description.

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

Dislodgeable Foliar Residues: Chemical

- specific dislodgeable foliar residue data have not been submitted for chlorim uron during registration review

. T his assessment uses HED’s default assumption that 25% of the application is available for transfer on day 0 following the application and the residues dissipate at a rate of 10% each following day.

Risk Estimate Equations : The algorithms used to estimate non

- cancer exposure and dose for occupational post

- application workers can be found in Appendix C.

Occupational Post

- application Non

- Cancer Dermal Risk Estimates

A summary of the post

- application exposure and risk estimates for the registered uses is provided in Table 9.2.2.2

. Only risk estimates for the highest contact activity for each crop are shown below

. Post

- application dermal exposure and risk estimates for the scenarios shown below resulted in MOEs greater t han 100 and are not of concern on day 0 (i.e., 12 hours following application)

. All other scenarios involving lower contact activities would have higher MOEs and are also not of concern.

10 Available: http:/

/www.epa.gov/pesticides/science/exposac_policy3.pdf

11 Available: http://www.epa.gov/pesticides/science/post

- app

- exposure

- data.html

### Page 22 of 46

Table 9.2.2.2

. Occupational Post

- application Non

- Cancer Exposure and Risk Estimates for Chlorimuron.

Crop/Site Activities Transfer Coefficient (cm 2 /hr) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3

Short

- and Intermediate

- term Corn, sweet, grain, processing Irrigation (Hand set) 1,900 0.18 0.00187 7,000
Corn, sweet, grain Hand, Detasseling 8,800 0.18 0.00865 1,500
Cranberry Scouting 1,100 0.04 0.00027 47,000

Peanuts Irrigation (Hand

set) 1,900 0.09 0.0092 14,000
Soybean Scouting 1,100 0.22 0.00137 9,500

1. DFR = Application Rate × F × (1

- D) t × 4.54E8 μg/lb × 2.47E

- 8 acre/cm 2 ; where F = 0.25 and D = 0.10 per day.

2. Daily Dermal Dose = [DFR (μg/cm 2 ) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × Dermal Absorption (%)] 

###  BW (kg). 3. MOE = Dermal NOAEL (mg/kg/day) / Dermal Dose (mg/kg/day); LOC=100.


### Restricted Entry Interval

The REI specified on the proposed label is based on the acute toxicity of chlorimuron

. Chlorimuron is classified as Toxicity Category III via the dermal route and Toxicity Category IV for skin irritation potential

. It is not a skin sensitizer

. Short

- and inter mediate

- term post

application risk estimates were not a concern on day 0 (i.e., 12 hours following application) for all post

- application activities

. Under 40 CFR 156.208 (c) (2) (iii), ai’s classified as Acute III or IV for acute dermal, eye irritation and primary skin irritation are assigned a 12

- hour REI

. Therefore, the [156 subpart K] Worker Protection Statement interim REI of 12 hours is adequate to protect agricultural workers from post

- application exposures to chlorimuron.

10.0 Public Health and Pesti cide Epidemiology Data D426223 , S. Recore, 12 May 2015

Chlorimuron

- ethyl was previously reviewed in 2010 (K. Middleton et al., 08/19/2010, D380339)

. At the time, there were no incidents reported for the single chemical chlorimuron ethyl in the Main Incide nt Data System ( IDS ) and three incidents reported to Aggregate IDS from January 1, 2000 to May 25, 2010

. In addition, there were two cases reported for chlorimuron ethyl to NIOSH SENSOR

- Pesticides from 1998 to 2007

. Upon review of these incidents, it was c oncluded that

“ Based on the low frequency and severity of incident cases, there does not appear to be a concern at this time that would warrant further investigation. ”

The current IDS analysis from January 1, 2010 through March 10, 2015, shows one incid ent reported involving chlorimuron ethyl in Main IDS involving multiple chemicals and six incidents reported to Aggregate IDS

. There were no single

- chemical incidents reported to IDS. The query of SENSOR

- Pesticides 1998

- 2011 identifies the same two cases, both involving multiple active ingredients, that were previously identified in 2010.

Based on the low frequency and mostly low severity of incident cases reported for chlorimuron ethyl in both IDS and NIOSH SENSOR

- Pesticides, there does not appear to be a concern at this

### Page 23 of 46

time that would warrant further investigation

. Several initial investigations within the AHS have made an epidemiological risk estimate of the association between chlori muron ethyl and various anatomical cancer endpoints; however, these cancer sites were either not related to use of chlorimuron ethyl (prostate or lung cancers, NHL, and cutaneous melanoma), or the association measured was non

- statistically significantly mo dest in size (<1.5) (breast, colorectal, pancreatic cancers). The Agency will continue to monitor the incident information and if a concern is triggered, additional analysis will be conducted.

11.0 Literature References

A literature search was performed for chlorimuron ethyl

. The search did not reveal information that would impact the current risk assessment

.

12.0 References

Author Barcode Date Title Dow, M. D365816 24 June 2009 Chlorimuron ethyl: Human Occupational Exposure/Risk Assessment for the Proposed Use on Field Corn and Soybeans. Cutchin, W. D358796 14 Sept 2009 Chlorimuron ethyl: Human Health Risk Assessment for Proposed Uses on Field Corn and Soybean. Middleton, K. D380339 19 Aug 2010 Chlorimuron ethyl: Review of Human Incidents

. McNeilly, D. D379636 27 Sept 2010 Chlorimuron ethyl

. Human Health Assessment Scoping Document in Support of Registration Review. Recore, S., Evans, E., Christensen, C. D426223 12 May 2015 Chlorimuron

- ethyl: Tier I Review of Human Incidents for Draft Risk Assessment

G. Orrick D427429 

### 8/12/2015 Drinking Water Exposure Assessment for the Registration Review of 22 Sulfonylurea Herbicides

### Page 24 of 46

Appendix A. Toxicology Data Requirements and Toxicology Profile

The toxicology requirements (40 CFR 158.340) for chlorimuron ethyl are presented below.

Test Technical
Required Satisfied
870.1100 Acute Oral Toxicity

................................ ....................... 870.1200 Acute Dermal Toxicity

................................ .................. 870.1300 Acute Inhalation Toxicity

................................ .............. 870.2400 Primary Eye Irritation

................................ .................... 870.2500 Primary Dermal Irritation

................................ .............. 870.2600 Dermal Sensitization

................................ ..................... Yes
Yes
Yes
Yes
Yes
Yes Yes
Yes
Yes
Yes
Yes
Yes 870.3100 Oral Subchronic (rodent)

................................ ............... 870.3150 Oral Subchronic (nonrodent)

................................ ......... 870.3200 21

- Day Dermal

................................ .............................. 870.3250 90

- Day Dermal

................................ .............................. 870.3465 21/90

- Day Inhalation

................................ ..................... Yes
Yes
Yes
No

No Yes
Yes
No
No Not required * 870.3700a Developmental Toxicity (rodent)

................................ .. 870.3700b Developmental Toxicity (nonrodent)

............................ 870.3800 Reproduction

................................ ................................ . Yes
Yes
Yes Yes
Yes
Yes 870.4100a Chronic Toxicity (rodent)

................................ .............. 870.4100b Chronic Toxicity (nonrodent)

................................ ........ 870.4200a Oncogenicity (rat)

................................ .......................... 870.4200b Oncogenicity (mouse)

................................ ................... 870.4300 Chronic/Oncogenicity

................................ ................... Yes
Yes
Yes
Yes
Yes Yes
Yes
Yes
Yes
Yes 870.5100 Mutagenicity

— Gene Mutation

- bacterial

..................... 870.5300 Mutagenicity

— Gene Mutation

- mammalian

............... 870.5385 Mutagenicity

— Mammalian Bone Marrow Chromosome Aberration Aberrations

.... 870.5550 Mutagenicity

— Unscheduled DNA Synthesis

............... Yes
Yes

Yes
No Yes
Yes

Yes
No
870.6200a Acute Neurotoxicity Screening Battery (rat)

................. 870.6200b 90

- Day Neurotoxicity Screening Battery (rat)

.............. 870.6300 Developmental Neurotoxicity

................................ ....... Yes
Yes
No Yes
Yes
No

870.7485 General Metabolism

................................ ...................... 870.7600 Dermal Penetration

................................ ........................ 870.7800 Immunotoxicity

................................ ............................. Yes
No

Yes Yes
No Not required *

* The Hazard and Science Policy Council (HASPOC) determined that subchronic inhalation and immunotoxicity studies are not required (TXR#s 0056401 and 0056723).

### Page 25 of 46

A.2. Toxicity Profiles

Table A.1

. Acute Toxicity Profile

– Chlorimuron ethyl Type of Study/Guide line Study Title MRID Results

870.1000 Acute Oral LD 50 , Rat (75%) 00131566 LD 50 (M/F) >5000 mg/kg Tox Category IV 870.1200 Acute Dermal LD 50 , Rabbit (75%) 00131567 LD 50 (M/F) >2000 mg/kg Tox Category III 870.1300 Acute Inhalation Toxicity, Rats (96%) 40843203 LC 50 (M/F) 5 mg/L Tox Category IV 870.2400 Primary Eye Irritation, Rabbit

(75%) 00131568 mild irritation @ 26 mg Tox Category III 870.2500 Primary Dermal Irritation, Rabbit (75%) 00131569 mild erythema and edema @ 0.5 g Tox Category IV 870.2600 Dermal Sensitization, Guinea Pig (75%) 00131570 Not a sensitizer

Table A.2. Subchronic, Chronic and Other Toxicity Profile for Chlorimuron ethyl Guide line Study Title MRID Dose Levels Results 870.3100 90

- Day Oral Toxicity,

Rat MRID 00131581 Levels tested: 0, 100, 2500, 7500 ppm, equivalent
to: [M]: 0, 7, 173, 551 mg/kg/day [F]: 0, 8, 209, 672 mg/kg/day NOAEL (M/F) = 7/8 mg/kg/day (100

ppm) LOAEL (M/F) = 173/209 mg/kg/day (2500 ppm) based on decreased body weight gain (14%) in females and liver pathology (margination of hepatocyte cytoplasmic content in centrilobular areas) in males

a 870.3100 90

- Day Oral Toxicity,

Mouse MRID 00143127 Levels tested: 0, 25, 125, 1250, 5000 ppm
equ ivalent to: [M]: 0, 6, 27, 268, 1030 mg/kg/day [F]: 0, 6, 30, 381, 1151mg/kg/day NOAEL (M/F) 1030/1151 mg/kg/day

LOAEL not established

870.3150 90

- Day Oral Toxicity,

Dog MRID 00132745 Levels tested: 0, 100, 1500, 7500 ppm equivalent
to: [M]: 0, 2.8, 45.8, 176.5 mg/kg/day [F]: 0, 2.9, 42.7, 187.1 mg/kg/day NOAEL (M/F) = 2.8/2.9 mg/kg/day (100

ppm) LOAEL (M/F) = 45.8/42.7 mg/kg/day (1500 ppm), based on hematologic changes (increased hematocrit, hemoglobin, erythrocyte counts in mid and high dose dogs) atrophy of thymus and prostate, increased absolute and relative liver weights.

870.3200 21

- Day Dermal,

Rabbit MRID 4864620 Levels tested: 0, 100, 400, 1000 NOAEL=1000 mg/kg/day

LOAEL=not determined 870.3465 21/90

- Day Inhalation Not required

### Page 26 of 46

Table A.2. Subchronic, Chronic and Other Toxicity Profile for Chlorimuron ethyl Guide line Study Title MRID Dose Levels Results 870.4100b Chronic Feeding, Dog MRID 00149579 Levels tested: 0, 25, 250, 1500 ppm, equivalent to: [M]: 0, 0.8, 10, 51 mg/kg/day [F]: 0, 0.8, 9, 55 mg/kg/day NOAEL = 10/9 mg/kg/day (250 ppm)

LOAEL = 51/55 mg/kg/day (1500 ppm), based on mild decrease in erythrocyte count, hematocrit, and hemoglobin concentration (mild anemia)

870.4200b Carcinogenicity, 18

-

Month Feeding, Mouse MRID 00145781 Levels tested: 0, 12.5, 125, 1250 ppm equivalent
to: [M]: 0, 1.6, 16, 160 mg/kg/day, [F]: 0, 2.1, 21, 216 mg/kg/day NOAEL (M/F) 160/216 mg/kg/day

LOAEL not established No treatment

- related neoplasms

870.4300 Chronic/Oncogenicity,

2

- Year

- Rat MRID 00149580 Levels tested: 0, 25, 250, 2500 ppm equivalent
to: [M&F]: 0, 1.25, 12.5, 125 mg/kg/day NOAEL = 12.5 mg/kg/day (250 ppm)

LOAEL= 125 mg/kg/day) (2500 ppm) based on decreased body weight in both sexes (8/24% [M/F], respectively) No treatment

- related neoplasms

870.3700a Developmental

Toxicity, Rat MRID 00131582 Levels tested: 0, 30, 150, 600 mg/kg/day GD 7

- 16 Maternal NOAEL = 30 mg/kg/day

Maternal LOAEL = 150 mg/kg/day based on decreased weight gain during GD 7

- 16 (11%) Developmental NOAEL = 30 mg/kg/day Developmental LOAEL = 150 mg/kg/day based on growth retardation (delayed ossification, centra and sternebrae ) 870.3700b Developmental

Toxicity, Rabbit MRID 00145782 Levels tested: 0, 13, 48, 300 mg/kg/day GD 7

- 19 Maternal NOAEL = 48 mg/kg/day

Maternal LOAEL = 300 mg/kg/day based on decreased weight gain during DG 7

- 19 (5%) Developmental NOAEL = 13 mg/kg/day Developmental LOAEL = 48 mg/kg/day based on delayed ossification 870.3800 Reproduction (1

-

Generation), Rat MRID 00131581 Levels tested: 0, 100, 2500, 7500 ppm equivalent to: [M]: 0, 7, 173, 551mg/kg/day [F]: 0, 8, 209, 672 mg/kg/day Reproductive NOAEL ( M/F) =

>551/672 mg/kg/day Reproductive LOAEL (M/F) = not established Offspring NOAEL = 7/8 mg/kg/day Offspring LOAEL = 173/209 mg/kg/day based on decreased litter weights Parental NOAEL (M/F) = 7/8 mg/kg/day Parental LOAEL (M/F) =173/209( mg/kg/day) based on

### Page 27 of 46

Table A.2. Subchronic, Chronic and Other Toxicity Profile for Chlorimuron ethyl Guide line Study Title MRID Dose Levels Results decreased body weight in females (12%) and liver pathology in males 870.3800 Reproduction (1

- year

interim sacrifice), Rat MRID 00143128 Levels tested: 0, 25, 250, 2500 ppm equivalent
to: [M]: 0, ?, 19, 195 mg/kg/day [F]: 0, ?, 23, 227 mg/kg/day Reproductive NOAEL 195/227

mg/kg/day Reproductive LOAEL not established Offspring NOAEL = 19/23 mg/kg/day Offspring LOAEL = 195/227 mg/kg/day based on decreased pup weight (20% and 19% in F 1a M and F, respectivel y; 12% in F 1b F) Parental NOAEL = 19/23 mg/kg/day Parental LOAEL = 195/227 mg/kg/day based on decreased body weight (12% F) 870.3800 Reproduction (2

-

Generation), Rat MRID 00149580 Levels tested: 0, 25, 250, 2500 ppm equivalent
to: [M]: 0, 1.7, 17, 177 mg/kg/day [F]: 0, 2.2, 21, 214 mg/kg/day Reproductive NOAEL 177/214

mg/kg/day Reproductive LOAEL = not established Offspring NOAEL = 17/21mg/kg/day Offspring LOAEL = 177/214 mg/kg/day based on reduced pup weight (20/19% in F 1a M/F; 7/12% in F 1b M/F; 13/13% in F 2a M/F; 20/18% in F 2b M/F ) and histopathologic findings in the cerebellum (cellular changes in the internal granular and external germinal layers) Parental NOAEL (M/F) 177/214 mg/kg/day Parental LOAEL not established 870.5100 Ames Bacterial

Mutagenicity Test MRID 00131571

--- Negative at 0.001 through 0.5 ·g/ml in presence of rat liver S

- 9 activation. 870.5300 In Vitro Mammalian

Gene Mutation

- Chinese Hamster Ovary BH4 Cells MRID 00131572

--- Not mutagenic in the presence or absence of S

- 9 activation

870.5385 Mammalian Bone

Marrow Chromosome Aberration Assay

- Rat MRID 00131573

--- This study was negative for induction of chromosome aberrations in the bone marrow cells of male or female Sprague

Dawley rats 6

- , 12

- , 24

- , and 48

- hr time points after gavage administration of 500

- 1500 mg/kg of test material 870.5550 Unscheduled DNA

Synthesis MRID 00132577

00155156 --- Additional data supporting a justification for the selection of the highest dose level was submitted and accepted

. Based on these findings, it was concluded that chlorimuron ethyl showed no evidence of UDS. 870.6200a Acute neurotoxicity

screening battery

- rats MRID



### 48704302 Levels tested:

mg/kg/day (M/F): 0, 100, 500, 2000 NOAEL = 100 mg/kg/day

LOAEL = 500 mg/kg/day, based on reduced arousal and reduced motor activity

### Page 28 of 46

Table A.2. Subchronic, Chronic and Other Toxicity Profile for Chlorimuron ethyl Guide line Study Title MRID Dose Levels Results 870.6200b Subchronic

neurotoxicity screening battery MRID 48704301 Levels tested: ppm: 0, 500, 1,250, and 3,750/5,000 (equivalent to mg/kg/day (M/F): 0/0, 27/35, 71/90, and 220 /259 NOAEL = 71 mg/kg/day

LOAEL = 220 mg/kg/day, based on decreased body weight and body weight gains and reduced food consumption in females.

870.7485 General Metabolism MRIDs 00154749 and 00149578 Doses = 16 and

3000 mg/kg of

14 C labeled phenyl or pyrimidinyl rings of chlorimuron ethyl

. Chlorimuron ethyl extensively

metabolized by both male and female rats at the low and high dose. Excretion was monitored up to 168 hrs. Elimination of radioactivity was equally via the urine & feces for low and high dose. Half

- life = 50 hrs. Major metabolites: HOPY

- DPX

- F6025, ODM

DPX

- F6025, HPY

- DPX

- F6025, DI

HOPY

- DPX

- F6025, DPX

- F6025 (See Appendix V for structures). 870.7800 Immunotoxicity Not required

### Page 29 of 46

Appendix B

. Review of Human Research

This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical

. These data are subject to ethics review pursuant to 40 CFR 26, have received that review, and are compliant with applicable ethi cs requirements

. For certain studies that 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 : http://www.epa.gov/pesticides/science/handler

- exposure

- data.html and http://www.epa.gov/pestici des/science/post

- app

- exposure

- data.html

. Appendix C

. Occupational Non

- cancer Algorithms

Occupational Non

- cancer Handler Algorithms

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

E=UE * AR * A * 0.001 mg/ug where: E = e xposure (mg ai/day), UE = u nit e xposure (μg ai/lb ai), AR = m aximum application rate according to registered label s (lb ai / A), and A = a rea treated or amount handled (e.g., A/day or 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 = e xposure (mg ai/day), AF = absorption fa ctor (dermal or inhalation), and BW = body weight (kg).

Margin of Exposure: Non

- c ancer 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/or inhalation dose s 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 a re calculated using the following formula:

MOE= POD
ADD where: MOE = margin of exposu re: value used by HED to represent risk estimates (unitless), POD = point of departure (mg/kg/day), and ADD = average daily dose absorbed in a given scenario (mg ai/kg/day).

Occupational Non

- cancer Post

- application Algorithms

### Page 30 of 46

Potential daily exposures for occupational post

- application workers are calculated using the following formulas:

DFR t 

### =AR * F* (1

- D) t 

### * ( 4.54E8 ug lb ) * ( 2.47E

- 8 A

cm 2 

### )

where: DFRt = dislodgeable foliage residue on day "t" (μg/cm2), AR = a pplication r ate (lb ai/acre), F = fraction of ai ret ained on foliage or 25% (unitless), D = fraction of residue that dissipates daily or 10% (unitless), and
t = number of days after application day (days)

.

E=TC * DFR t 

### * ET * 0.001 mg
ug where: E = e xposure (mg ai/day), TC = t ransfer coefficient (cm 2 /hr), DFR t = d islodgeable f

oliar r esidue on day “t” (μg/cm 2 ), and ET = e xposure t ime (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 = e xposure (mg ai/day), AF = absorption fa ctor (dermal), 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 a re calculated using the following formula:

MOE= POD
ADD where: MOE = margin of exposure: value used by HED to represent risk estimates (unitl ess), POD = point of departure (mg/kg/day), and ADD = average daily dose absorbed in a given scenario (mg ai/kg/day).

### Page 31 of 46

Appendix D

. Dietary Exposure/Risk Modeling Input and Output

Filename: Chlorimuron.R08 Chemical: Chlorimuron RfD(Chronic): .09 mg/kg b w/day NOEL(Chronic): 0 mg/kg bw/day RfD(Acute): 1 mg/kg bw/day NOEL(Acute): 0 mg/kg bw/day Date created/last modified: 04

- 08

- 2015/11:58:43 Program ver. 3.16, 03

- 08

- d

----------------------------------------------------------------------------------- EPA Crop Def Res Adj.Factors Comment Code Grp Commodity Name (ppm) #1 #2

---------- -- -- ------------------------------- ---------- ------ ------ ------- 0600347000 6 Soybean, seed 0.050000 1.000 1.000 0600349000 6 Soybean, soy milk 0.050000 1.000 1.000 0600349001 6 Soybean, soy mi lk

- babyfood or in 0.050000 1.000 1.000 0600350000 6 Soybean, oil 0.050000 1.000 1.000 0600350001 6 Soybean, oil

- babyfood 0.050000 1.000 1.000 0603348000 6C Soybean, flour 0.050 000 1.000 1.000 0603348001 6C Soybean, flour

- babyfood 0.050000 1.000 1.000 1302057000 13B Blueberry 0.020000 1.000 1.000 1302057001 13B Blueberry

- babyfood 0.020000 1.000 1.000 1307 130000 13G Cranberry 0.020000 1.000 1.000 1307130001 13G Cranberry

- babyfood 0.020000 1.000 1.000 1500120000 15 Corn, field, flour 0.010000 1.000 1.000 1500120001 15 Corn, field, flour

- babyfood 0.010000 1.000 1.000 1500121000 15 Corn, field, meal 0.010000 1.000 1.000 1500121001 15 Corn, field, meal

- babyfood 0.010000 1.000 1.000 1500122000 15 Corn, field, bran 0.0 10000 1.000 1.000 1500123000 15 Corn, field, starch 0.010000 1.000 1.000 1500123001 15 Corn, field, starch

- babyfood 0.010000 1.000 1.000 1500124000 15 Corn, field, syrup 0.010000 1.000 1.000 15 00124001 15 Corn, field, syrup

- babyfood 0.010000 1.000 1.000 1500125000 15 Corn, field, oil 0.010000 1.000 1.000 1500125001 15 Corn, field, oil

- babyfood 0.010000 1.000 1.000 8601000000 86A Water, dire ct, all sources 0.751000 1.000 0.655 Fact. 2 = 492 / 751 (chronic/acute H2O) 8602000000 86B Water, indirect, all sources 0.751000 1.000 0.655 Fact. 2 = 492 / 751 (chronic/acute H2O) 9500263000 O Peanut 0.020000 1.000 1.000 9500264000 O Peanut, butter 0.020000 1.000 1.000 9500265000 O Peanut, oil 0.020000 1.000 1.000

### Page 32 of 46

US EPA Ver. 3.16, 03

- 08

- d
DEEM

- FCID Chronic analysis for CHLORIMURON NHANES 2003

- 2008 2

- day Residue file name: Chlorimuron.R08 Adjustment factor #2 used. Analysis Date 04

- 08

- 2015/11:46:01 Residue file dated: 04

- 08

- 2015/11:12:22 Reference dose (RfD, Chronic) = .09 mg/kg bw/day

=============================================================================== Total exposure by population subgroup

------------------------------------ -------------------------------------------

Total Exposure

----------------------------------- Population mg/kg Perc ent of Subgroup body wt/day Rfd

-------------------------------------- ------------- ---------------- Total US Population 0.010345 11.5% Hispanic 0.009883 11.0%
Non

- Hisp

- White 0.010637 11.8%
Non

- Hisp

- Black 0.008543 9.5%
Non

- Hisp

- Other 0.01192 5 13.2% Nursing Infants 0.009351 10.4%
Non

- Nursing Infants 0.034382 38.2% Female 13+ PREG 0.009738 10.8% Children 1

- 6 0.013302 14.8% Children 7

- 12 0.008652 9.6% Male 13

- 19 0.007127 7.9% Female 13

- 19/NP 0.007975 8.9% Male 20+ 0.009631 10.7% Female 20+/NP 0.010851 12.1% Seniors 55+ 0.009988 11.1% All Infants 0.026654 29.6% Female 13

- 50 0.010286 11.4% Children 1

- 2 0.014977 16.6% Children 3

- 5 0.012624 14.0% Children 6

- 12 0.009099 10.1% Youth 13

- 19 0.007555 8.4% Adults 20

- 49 0.010313 11. 5% Adults 50

- 99 0.010190 11.3% Female 13

- 49 0.010275 11.4%

-------------------------------------------------------------------------------

### Page 33 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 RAC/FF intake summed over 24 hours
Run Comment: ""

===============================================================================

Summary calculations

-- per capita:

95th Percentile 99th Percentile 99.9th Percentile Exposure % aRfD Exposure % aRfD Exposure % aRfD

---------- -------- ---------- -------- ---------- -------- Total US Population: 0.040989 4.10 0 .067488 6.75 0.128489 12.85 All Infants: 0.128345 12.83 0.173678 17.37 0.256576 25.66 Children 1

- 2: 0.063275 6.33 0.095464 9.55 0.235102 23.51 Children 3

- 5: 0.051309 5.13 0.079153 7.92 0.125941 12.59 Children 6

- 12: 0.039140 3.91 0.064122 6.41 0.098832 9.88 Youth 13

- 19: 0.034153 3.42 0.056287 5.63 0.085017 8.50 Adults 20

- 49: 0.040398 4.04 0.059937 5.99 0.087504 8.75 Adults 50

- 99: 0.035994 3.60 0.054352 5.44 0.085668 8.57 Female 13

- 49: 0.040893 4.09 0.060056 6.01 0.084457 8.45

### Page 34 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 RAC/FF intake summed over 24 hours Run Comment: ""

============================= ==================================================

Summary calculations

-- users:

95th Percentile 99th Percentile 99.9th Percentile Exposure % aRfD Exposure % aRfD Exposure % aRfD

---------- -------- ---------- -------- ---------- -------- Total US Population: 0.041007 4.10 0.067515 6.75 0.128531 12.85 All Infants: 0.131773 13.18 0.189910 18.99 0.256753 25. 68 Children 1

- 2: 0.063290 6.33 0.095466 9.55 0.235105 23.51 Children 3

- 5: 0.051309 5.13 0.079153 7.92 0.125941 12.59 Children 6

- 12: 0.039141 3.91 0.0641 23 6.41 0.098832 9.88 Youth 13

- 19: 0.034159 3.42 0.056289 5.63 0.085017 8.50 Adults 20

- 49: 0.040400 4.04 0.059938 5.99 0.087506 8.75 Adults 50

- 99: 0.035998 3.60 0.054354 5.44 0.085669 8.57 Female 13

- 49: 0.040893 4.09 0.060056 6.01 0.084457 8.45

### Page 35 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 0 8

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.000000 mg/kg body

- wt/day RAC/FF intake summed over 24 hours Run Comment: ""

===============================================================================

Total US Population Daily Exposure Analysis /a

------------------- (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.015769 0.015794 Standard Deviation 0.014375 0.014373 Standard Error of mean 0.000065 0.000065 Percent of aRfD 1.58 1.58

Percent of Person

- Days that are User

- Days = 99.84%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ------- --- --------- 10.00 0.002419 0.24 90.00 0.031618 3.16 20.00 0.005195 0.52 95.00 0.041007 4.10 30.00 0.007609 0.76 97.50 0.051801 5.18 40.00 0.009994 1.00 99.00 0.067515 6.75 50.00 0.012599 1.26 99.50 0.082328 8.23 60.00 0.015549 1.55 99.75 0.097503 9.75 70.00 0.018959 1.90 99.90 0.128531 12.85 80.00 0.023468 2.35

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.002367 0.24 90.00 0.031599 3.16 20.00 0.005162 0.52 95.00 0.040989 4.10 30.00 0.007579 0.76 97.50 0.051773 5.18 40.00 0.009971 1.00 99.00 0.067488 6.75 50.00 0.012576 1.26 99.50 0.082279 8.23 60.00 0.015529 1.55 99.75 0.097471 9.75 70.00 0.018941 1.89 99.90 0.128489 12.85 80.00 0.023449 2.34

------------------------------------------------------------------------------- a/ Analysis based on all two

- day participant records in NHANES 2003

- 2008 2

- Day with 2 days of valid drinking water records.

### Page 36 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.000000 mg/kg body

- wt/day RAC/FF intake summed over 24 hours Run Comment: ""

===============================================================================

All Infants Daily Exposure Analysis

----------- (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.040651 0.044814 Standard Deviation 0.045130 0.045374 Standard Error of mean 0.000903 0.000949 Percent of aRfD 4.07 4.48

Percent of Person

- Days that are User

- Days = 90.71%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.000261 0.03 90.00 0. 106724 10.67 20.00 0.002380 0.24 95.00 0.131773 13.18 30.00 0.007809 0.78 97.50 0.148414 14.84 40.00 0.016893 1.69 99.00 0.189910 18.99 50. 00 0.031183 3.12 99.50 0.200542 20.05 60.00 0.050135 5.01 99.75 0.233871 23.39 70.00 0.065966 6.60 99.90 0.256753 25.68 80.00 0.082569 8. 26

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- -------- -- ---------- --------- 10.00 0.000020 0.00 90.00 0.103662 10.37 20.00 0.000308 0.03 95.00 0.128345 12.83 30.00 0.004184 0.42 97.50 0.146126 14.61 40.00 0.010654 1.07 99.00 0.173678 17.37 50.00 0.022606 2.26 99.50 0.200028 20.00 60.00 0.043150 4.31 99.75 0.231885 23.19 70.00 0.062864 6.29 99.90 0.256576 25.66 80.00 0.078732 7.87

### Page 37 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.000000 mg/kg body

- wt/day RAC/FF intake summed over 24 ho urs Run Comment: ""

===============================================================================

Children 1

- 2 Daily Exposure Analysis

------------ (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.022810 0.022819 Standard Deviation 0.022327 0.022327 Stan dard Error of mean 0.000408 0.000408 Percent of aRfD 2.28 2.28

Percent of Person

- Days that are User

- Days = 99.96%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt /day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.002319 0.23 90.00 0.048759 4.8 8 20.00 0.006346 0.63 95.00 0.063290 6.33 30.00 0.010007 1.00 97.50 0.078475 7.85 40.00 0.013597 1.36 99.00 0.095466 9.55 50.00 0.017206 1.72 99.50 0.132912 13.29 60.00 0.021318 2.13 99.75 0.145762 14.58 70.00 0.026843 2.68 99.90 0.235105 23.51 80.00 0.035296 3.53

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- - --------- --------- 10.00 0.002296 0.23 90.00 0.048755 4.88 20.00 0.006338 0.63 95.00 0.063275 6.33 30.00 0.010001 1.00 97.50 0.078466 7.85 40.00 0.013588 1.36 99.00 0.095464 9.55 50.00 0.017200 1.72 99.50 0.132911 13.29 60.00 0.021309 2.13 99.75 0.145750 14.57 70.00 0.026833 2.68 99.90 0.235102 23.51 80.00 0.035288 3.53

### Page 38 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.000000 mg/kg body

- wt/day RAC/FF intake summed over 24 hou rs Run Comment: ""

===============================================================================

Children 3

- 5 Daily Exposure Analysis

------------ (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.019209 0.019209 Standard Deviation 0.017378 0.017378 Standard Error of mean 0.000327 0 .000327 Percent of aRfD 1.92 1.92

Percent of Person

- Days that are User

- Days = 100.00%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percenti le Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.001778 0.18 90.00 0.040676 4.07 20.00 0.005999 0.60 95.00 0.051309 5.13 30.00 0.008983 0.90 97.50 0.062160 6.22 40.00 0.011962 1.20 99.00 0.079153 7.92 50.00 0.015315 1.53 99.50 0.093587 9.36 60.00 0.018874 1.89 99.75 0.103124 10.31 70.00 0.023074 2.31 99.90 0.125941 12.59 80.00 0.029466 2.95

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- - --------- ---------- --------- 10.00 0.001778 0.18 90.00 0.040676 4.07 20.00 0.005999 0.60 95.00 0.051309 5.13 30.00 0.008983 0.90 97.50 0.062160 6.22 40.00 0.011962 1.20 99.00 0.079153 7.92 50.00 0.015315 1.53 99.50 0.093587 9.36 60.00 0.018874 1.89 99.75 0.103124 10.31 70.00 0. 023074 2.31 99.90 0.125941 12.59 80.00 0.029466 2.95

### Page 39 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.000000 mg/kg body

- wt/day RAC/FF intake summed o ver 24 hours Run Comment: ""

===============================================================================

Children 6

- 12 Daily Exposure Analysis

------------- (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.013850 0.013851 Standard Deviation 0.013186 0.013186 Standard Error of mean 0.00 0163 0.000163 Percent of aRfD 1.39 1.39

Percent of Person

- Days that are User

- Days = 99.99%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.001404 0.14 90.00 0.028689 2.87 20.00 0.003889 0.39 95.00 0.039141 3.91 30.00 0.005929 0.59 97.50 0.049490 4.95 40.00 0.008161 0.82 99.00 0.064123 6.41 50.00 0.010566 1.06 99. 50 0.076224 7.62 60.00 0.013359 1.34 99.75 0.086564 8.66 70.00 0.016936 1.69 99.90 0.098832 9.88 80.00 0.021420 2.14

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0 .001402 0.14 90.00 0.028689 2.87 20.00 0.003888 0.39 95.00 0.039140 3.91 30.00 0.005928 0.59 97.50 0.049489 4.95 40.00 0.008160 0.82 99.00 0.064122 6.41 50.00 0.010565 1.06 99.50 0.076224 7.62 60.00 0.013358 1.34 99.75 0.086562 8.66 70.00 0.016935 1.69 99.90 0.098832 9.88 80.00 0.021420 2.14

### Page 40 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.000000 mg/kg body

- wt/day RAC/FF intake summed over 24 hours
Run Comment: ""

====================== =========================================================

Youth 13

- 19 Daily Exposure Analysis

----------- (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.011511 0.011513 Standard Deviation 0.011750 0.011750 Standard Error of mean 0.000127 0.000127 Percent of aRfD 1.15 1.15

Percent of Person

- Days that are User

- Days = 99.98%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.000452 0.05 90.00 0.025134 2.51 20.00 0.002743 0.27 95.00 0.034159 3.42 30.00 0.004584 0.46 97.50 0.044063 4.41 40.00 0.006308 0.63 99.00 0.056289 5.63 50.00 0.008263 0.83 99.5 0 0.067375 6.74 60.00 0.010757 1.08 99.75 0.078791 7.88 70.00 0.013672 1.37 99.90 0.085017 8.50 80.00 0.017940 1.79

Estimated percentile of per

- capita d ays falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0. 000448 0.04 90.00 0.025132 2.51 20.00 0.002738 0.27 95.00 0.034153 3.42 30.00 0.004581 0.46 97.50 0.044062 4.41 40.00 0.006306 0.63 99.00 0.056287 5.63 50.00 0.008261 0.83 99.50 0.067369 6.74 60.00 0.010754 1.08 99.75 0.078791 7.88 70.00 0.013670 1.37 99.90 0.085017 8.50 80.00 0.017939 1.79

### Page 41 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.000000 mg/kg body

- wt/day RAC/FF intake summed over 24 hours Run Comment: ""

===============================================================================

Adults 20

- 49 Daily Exposure Analysis

------------ (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.015725 0.015729 Standard Deviation 0.012900 0.012899 Stan dard Error of mean 0.000113 0.000113 Percent of aRfD 1.57 1.57

Percent of Person

- Days that are User

- Days = 99.98%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt /day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.002350 0.23 90.00 0.032053 3.2 1 20.00 0.005266 0.53 95.00 0.040400 4.04 30.00 0.007802 0.78 97.50 0.048828 4.88 40.00 0.010277 1.03 99.00 0.059938 5.99 50.00 0.012982 1.30 99.50 0.068782 6.88 60.00 0.015963 1.60 99.75 0.076040 7.60 70.00 0.019429 1.94 99.90 0.087506 8.75 80.00 0.023968 2.40

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.002341 0.23 90.00 0.032051 3.21 20.00 0.005261 0.53 95.00 0.040398 4.04 30.00 0.007797 0.78 97.50 0.048825 4.88 40.00 0.010274 1.03 99.00 0.059937 5.99 50.00 0.012978 1.30 99.50 0.068777 6.88 60.00 0.015961 1.60 99.7 5 0.076037 7.60 70.00 0.019426 1.94 99.90 0.087504 8.75 80.00 0.023965 2.40

### Page 42 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analys is for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1.00000 0 mg/kg body

- wt/day RAC/FF intake summed over 24 hours
Run Comment: ""

===============================================================================

Adults 50

- 99 Daily Exposure Analysis

------------ (mg/kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.015540 0.015544
Stan dard Deviation 0.011128 0.011127 Standard Error of mean 0.000099 0.000099 Percent of aRfD 1.55 1.55

Percent of Person

- Days that are User

- Days = 99.97%

Estimated percentile of user

- days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.004160 0.42 90.00 0.028899 2.89 20.00 0.006636 0.66 95.00 0.035998 3.60 30.00 0.008841 0.88 97.50 0.043039 4.30 40.00 0.010995 1.10 99.00 0.054354 5.44 50.00 0.013358 1.34 99.50 0.062596 6.26 60.00 0.015979 1.60 99.75 0.071509 7.15 70.00 0.018836 1.88 99.90 0.085669 8.57 80.00 0.022784 2.28

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.004153 0.42 90.00 0.028897 2.89 20.00 0.006630 0.66 95.00 0.035994 3.60 30.00 0.008838 0.88 97.50 0.043035 4.30 40.00 0.010992 1.10 99.00 0.054352 5.44 50.00 0.013354 1.34 99.50 0.062593 6.26 60.00 0.015974 1.60 99.7 5 0.071504 7.15 70.00 0.018833 1.88 99.90 0.085668 8.57 80.00 0.022782 2.28

### Page 43 of 46

US EPA Ver. 3.18, 03

- 08

- d
DEEM

- FCID ACUTE Analysis for CHLORIMURON NHANES 2003

- 2008 2

- Day Residue file: Chlorimuron.R08 Adjustment factor #2 NOT used. Analysis Date: 04

- 08

- 2015/12:00:55 Residue file dated: 04

- 08

- 2015/11:58:43 Acute Reference Dose (aRfD) = 1 .000000 mg/kg body

- wt/day RAC/FF intake summed over 24 hours
Run Comment: ""

===============================================================================

Female 13

- 49 Daily Exposure Analysis

------------ (mg /kg body

- weight/day) per Capita per User

----------- ----------- Mean 0.015667 0.015667 Standard Deviation 0.013165 0.0 13164 Standard Error of mean 0.000123 0.000123 Percent of aRfD 1.57 1.57

Percent of Person

- Days that are User

- Days = 100.00%

Estimated percentile of user

- days falling below calculated exposur e in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- ---------- ---------- --------- 10.00 0.001996 0.20 90.00 0.032752 3.28 20.00 0.004917 0.49 95.00 0.040893 4.09 30.00 0.007304 0.73 97.50 0.049529 4.95 40.00 0.009968 1.00 99.00 0.060056 6.01 50.00 0.012832 1.28 99.50 0.066956 6.70 60.00 0.015862 1.59 99.75 0.072568 7.26 70.00 0.019465 1.95 99.90 0.084457 8.45 80.00 0.024234 2.42

Estimated percentile of per

- capita days falling below calculated exposure in mg/kg body

- wt/day with Percent of aRfD

Percentile Exposure % aRfD Percentile Exposure % aRfD

---------- ---------- --------- - --------- ---------- --------- 10.00 0.001996 0.20 90.00 0.032752 3.28 20.00 0.004917 0.49 95.00 0.040893 4.09 30.00 0.007303 0.73 97.50 0.049529 4.95 40.00 0.009968 1.00 99.00 0.060056 6.01 50.00 0.012832 1.28 99.50 0.066956 6.70 60.00 0.015862 1.59 99.75 0.072566 7.26 70.00 0. 019465 1.95 99.90 0.084457 8.45 80.00 0.024234 2.42

### Page 44 of 46

Appendix E. Nomenclature and Physical/Chemical Properties

TABLE E.1 Chlorimuron ethyl Nomenclature Compound Chlorimuron ethyl

Common name Chlorimuron ethyl Company experimental name N/A

IUPAC name ethyl 2

- (4

- chloro

- 6

- methoxypyrimidin

- 2

- ylcarbamoylsulfamoyl)benzoate

CAS name ethyl 2

- [[[[(4

- chloro

- 6

- methoxy

- 2

- pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoate

CAS # 90982

- 32

- 4

TABLE E.2 Physicochemical Properties of the Technical Grade Chlorimuron ethyl

Parameter Value Reference
Melting point/range 181  C PP#3G2959; 1/10/84; S. Creeger
pH 4.4 PP#3G2959; 1/10/84; S. Creeger Density 1.51 g/cc PP#3G2959; 1/10/84; S. Creeger Water solubility (mg/L) pH 1.3 = 1.5 pH 1.9 = 1.5 pH 2.5 = 1.5 pH 4.2 = 4.1 pH 5.0 = 9.0 pH 5.8 = 99 pH 6.5 = 450 pH 7.0 = 1200 PP#3G2959; 1/10/84; S. Creeger

Solvent solubility (mg/100 mL at 25  C) Acetone = 7.05 Acetonitrile = 3.10 Benzene = 0.815 Ethyl Acetate = 2.36 Ethyl Alcohol = 0.392

n

- Hexane = 0.006 Methyl Alcohol = 0.740 Methylene Chloride = 15.3 Xylene = 0.283 PP#3G2959; 1/10/84; S. Creeger

Vapor pressure at 25  C 1.5 x 10

- 5 mm Hg PP#3G2959; 1/10/84; S. Creeger
Dissociation constant (pK a ) at 25  C 4.2 PP#3G2959; 1/10/84; S. Creeger
Octanol/water partition coefficient Log(K OW ) 1.3 PP#3G2959; 1/10/84; S. Creeger

### Page 45 of 46

Appendix F. Spray Drift Detailed Description

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 off

target and can lead to exposures to those the chemical may directly contact

. Sprays can also dep osit on surfaces where individuals come into contact with residues on these surfaces, lead ing to indirect exposures (e.g., children playing on lawns where residues have deposited next to treated fields).

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
preve nt them 12



### . [ 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 applica tions 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 anal ogous 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 util ized

. Essentially, a residential turf assessment based on exposure to deposited residues has been completed to address drift from the agricultural applications of chlorimuron ethyl

. In the spray drift scenario, the deposited residue value was determined ba sed on the amount of spray drift that may occur at varying distances from the edge of the treated field using the AgDrift (v2.1.1) model and the Residential Exposure Assessment Standard Operating Procedures Addenda 1: Consideration of Spray Drift Policy . O nce the deposited residue values were determined, the remainder of the spray drift assessment was based on the algorithms and input values specified in the 2012 Standard Operating Procedures for Residential Risk Assessment (SOPs)

. A screening approach wa s developed based on the use of the AgDrift model in situations where specific label guidance that defines application parameters is not available 13 14



### . 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 t his 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 ecologica l 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

12 This approach is consistent with the requ irements of the EPA’s Worker Protection Standard.

13 http://www.agdrift.com/

14 Note that for many cases the scenarios outlined in the screening approach represent actual use practice so risk assessors should be aware and characterize these appropriately.

### Page 46 of 46

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

. Section 6.1 .1 provides the screening level drift related risk estimates.

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

. In order to account for this issue and to provide additional risk management options additional spray drift deposition fractions were also considered

. These drift estimates represent plausible options for pesticide labels

.