UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460



### MEMORANDUM

DATE: January 21, 2015 OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION



### SUBJECT: Paclobutrazol: Revised Preliminary Occupational and Residential Exposure/Risk

Assessment for Registration Re view



### PC Code: 125601



### Decision No.: 455061



### Petition No.: DP Barcode: D427481 

### Registration No.: Regulatory Action: Registration Re v iew



### Case No.: 7002 

### Risk Assessment Type: Single

Chemical/ Aggregate



### TXRNo.:

MRID No.:

FROM: CAS No.: 76738-62-0

40 

### CFR:

Monica Hawkins, Ph.D., M.P .H., Environmental Health Scientist 

# Jr'l

# ~~ Risk Assessment Branch 6

Health Effects Division (7509P)



### THROUGH: Donna Davis

, Acting Chief

Risk Assessment Branch 6

Health Effects Division (7509P)



### TO: Khue Nguyen

Risk Management and Implementation Branch I

Pesticide Re-evaluation Division (7508P)

and

Sheila Piper, Risk Assessor

Risk Assessment Branch 6

Health Effects Division (7509P)

Page I of 44

### INTRODUCTION

As part of Registration Review, the Pesticide Re

- evaluation Division (PRD) of OPP requested

that HED conduct a revised occupational and residential exposur e/risk assessment for paclobutrazol for application as a foliar spray for turf (including parks, athl etic fields, and golf courses); a foliar spray for ornamentals in greenhouses and nurseries; as a tree injection; as a tree

root d rench; and as a seed treatment (on cucurbit, pepper, tomato , broccoli, cauliflower, and cabbage seeds)

. As part of Registrati on Review, the paclobutrazol hazard assessment was revisited by HED

.

The revised occupational and residential exposure asses sment is based on the previous 20 13 risk

assess ment ( D394230, S. Piper, C. Smith, M. Hawkins, and N. McCarroll, 9/11/13 ). The document was revised to incorporate data from the acceptable/ guideline acute neurotoxicity and to account for the data waivers granted for the subchronic inhalation and the immunotoxicity studies by the Hazard and Science Policy Council on February 27, 201 4. As a result of the meeting

, the 10X database uncertainty factor was removed. In addition, the dermal absorption factor was updated to be consistent with current HED policy.

It is HED policy to use the best available data to assess exposure. Sever al sources of generic data were used in this assessment as surrogate data in the absence of chemical

- specific data, including Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1) ; the Agricultural Handler Exposure Task Force (AHETF) database; the Ou tdoor Residential Exposure Task Force (ORETF) database; the Agricultural Reentry Task Force (ARTF) database; ExpoSAC Policy 14 (SOPs for Seed Treatment); the Res idential SOPs ( Lawns/ Turf ), a chemical

- specific turf transferable residue study (MRID 45214201), and a chemical

- specific dislodgeable foliar residue study ( MRID 45310801 and 45336601 )

. Some of these data are proprietary, and subject to the data protection provisions of the Federal Insecticide, Fungicide, and Rodenticide Act ( FIFRA).

Page 2 of 44

### Table of Contents

1.0 Executive Summary

................................ ................................ ................................ ........... 4

2.0 Risk Assessment Conclusions and Recommendations

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

2.1 Summary of Risk Estimates

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

2.2 Label Recommendations from Occupational Assessment

................................ .......... 7

2.3 Label Recommendations from Residential Assessment

................................ ............. 7

2.4 Data Deficiencies and Requirements

................................ ................................ ............ 7

3.0 Hazard Characterization

................................ ................................ ................................ ... 7

4.0 Use Profile

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

5.0 Residential Exposure and Risk Estimates

................................ ................................ ..... 12

5.1 Residential Handler Exposure/Risk Estimates

........... Error! Bookmark not defined.

5.2 Residential Post

- application Exposure/Risk Estimates

................................ ............ 12

5.3 Residential Risk Estimates for Use in Aggregate Assessment

................................ .. 15

5.4 Spray Drift

................................ ................................ ................................ .................... 15

5.5 Residential Bystander Post

- Application Inhalation Exposure

................................ 16

6.0 Occupational Exposure and Risk Estimates

................................ ................................ .. 16

6.1 Occupational Handler Exposure/Risk Estimates

................................ ...................... 16

6.2 Occupational Post

- application Exposure/Risk Estimates

................................ ........ 28

6.2.1 Occupational Post

- application Inhalation Exposure/Risk Estimates

.................. 28

6.2.2 Occupational Post

- application Dermal Exposure/Risk Estimates

....................... 29

Appendix A. Summary of Occupational and Residential Non

- cancer Algorithms

............. 34 Appendix B. Paclobutrazol DFR and TTR Study Results

................................ ..................... 41

Page 3 of 44

### 1.0 Executive Summary

Paclobutrazol, is a triazole plant growth regulator that slows vegetative growth by inhibiting gibberilin biosysthesis creating more compact plants.

Use Profile

There are a number of existing uses for paclobutrazol with formulations including liquids,

wetta ble powders, and granulars. Paclobutrazol is currently regis tered for use as a foliar spray for turf (including parks, athletic fields, and golf courses); a foliar spray for ornamentals in greenhouses and nurseries; as a tree injection; as a tree root d rench; and as a seed treatment (on cucurbit, pep per, tomato, broccoli, cauliflower, and cabbage seeds).

Hazard Profile

Paclobutrazol is classified as Toxicity Category III via the dermal route and or skin irritation potential based on studies submitted in 2012. It is not a skin sensitizer. Quantif ication of short

term (1

- 30 days) and intermediate

- term (1

- 6 months) dermal and inhalation risks for paclobutrazol was performed using a developmental oral toxicity study. T he Lowest Observed

Adverse E ffect Level ( LOAEL ) from this study was 40 mg/kg/day based on partial ossification

of the 7 th 

### vertebra and an increased incidence of 14 th 

### rib on a fetal and litter basis at a dose that was not maternally toxic (LOAEL = 40 mg/kg/day)

. The No Observed Adverse Effect Level ( NOAEL ) from this study was 10 mg/kg /day. Based on a dermal absorption stu dy in male rats, absorption of p aclobutrazol was deemed to be 18.7 % after 10 hours. Since both the dermal and inhalation endpoints were based on the same toxi cological effects, these route s may be combined

to result in a total margin of exposure ( MOE )

. Since the dermal and inhalation points of departure (PODs) are based on developmental and/or fetal effects, the body weight appropriate

for dermal and inhalation assessments is 69 kg

. Quantifica tion of an incidental oral risk wa s performed using a reproductive rat toxicity study. The o ffspring LOAEL from this study was

116.9 mg/kg /day based on the increased incidence of chromodacryorrhea, thickened eyelids and dental malocclusion, increased liver weights, mottling or accentuation of the lobular structure of the liver along with liver enlargement, pallor and discoloration in male and female pups of both generations . Th e NOAEL from this study was 23.2 mg/kg/day

. A target MOE of 100 is

conside red adequate for all exposure scenarios (10X for interspecies extrapolation, 10X for

intr aspecies variability ).

There are no proposed or currently registered food uses for paclobutrazol. Carcinogenicity studies are not required for non

- food use chemical s. Carcinogenicity studies in mice and rats

are available. The Agency was unable to determine the potential carcinogenicity of paclobutrazol because the maximum tolerated dose (MTD) was not achieved in the 2

- year carcinogenicity/ chronic study in rats and the carcinogenicity/chronic study in mice. The carcinogenic potential will be re

- evaluated if the use pattern changes (i.e., food uses are proposed).

Residential Exposure and Risk

Page 4 of 44

### Paclobutrazol is currently not registered for homeowner use on residential lawns. Therefore, a residential handler exposure assessment was not conducted. Paclobutrazol is applied commercially to parks and golf courses; therefore residential post

- applicat ion exposure was

assessed. A chemical

- specific turf transferable residue (TTR) study was available and was used

to estimate transferable residues from turf treated with liquid formulations

. Dermal post

application risks were assessed for adults, and chil dren 11 to 16 years old. All adult and older children golfing dermal risk estimates for both liquid and granular formulations are greater than HED’s level of concern (MOEs ≥ 100). All adults on treated turf dermal risk estimates for both liquid and granu lar formulations MOEs range from 170 to 1,100. All children 1

– 2 years old

oral non

- dietary ingestion risk from hand

- to

- mouth activity on treated turf estimates for both liquid and granular formulations MOEs range from 210 to 1,400,000.

A quantitative spray drift assessment for paclobutrazol is not required because the maximum application rate to a crop/target site multiplied by the adjustment factor for drift of 0.26 is less than the maximum direct spray residential turf application rate (0.75 lb ai/A ) 1 

### for the paclobutrazol products. The turf post

- application MOEs are protective for any potential exposures related to spray drift for paclobutrazol.

Occupational Exposure and Risk

The occupational handler assessment was completed assuming the maximum label application rate for each crop. Based on the activity use pattern, the duration of exposure is expected to be

short

- term (1 to 30 d ays) and intermediate

- term (1 to 6 months). Lo ng

- term exposures (greater than 6 months) are not anticipated based on the existing use pattern. For the dermal and

inhalation route s of exposure, the same points of departure were chosen for short

- term and

intermediate

- term exposures; therefore, risks ar e the same for both durations of exposure. Occupational handler exposures to the existing turf, ornamental, and tree uses of paclobutrazol may occur via the dermal and inhalation route. The short

- and intermediate

- term risk estimates for the occupational handler scenarios are greater than HED’s LOC (MOEs ≥ 100) with the exception of mixing/loading/applying liquids via a backpack sprayer. The MOEs range from 29 to 19,000,000. The backpack sprayer equipment scenario is still not greater than HED’s LOC (MOEs < 100) even with the use of personal protective equipment PPE of a double layer and gloves (MOE = 58).

Occupational handler exposures to the existing seed uses of paclobutrazol may occur via the dermal and inhalation route for both primary handlers (i.e., those who treat the seed in commercial seed treatment facilities) and secondary handlers (i.e., those w ho plant paclobutrazol treated seeds). The short

- and intermediate

- term risk estimates for all primary and secondary handler scenarios are greater than HED’s LOC (MOEs ≥ 100 ) at varying levels of PPE

. The

short

- and intermediate

- term risk estimates for al l primary and secondary handler scenarios MOEs range from 16,000 to 13,000,000.

Occupational post

- application exposures to the existing uses of paclobutrazol may occur via the

dermal route. The results indicate that occupational post

- applica tion risks are greater than

HED’s LOC (MOE s ≥ 100 ) on day zero after application for all post

- application activities that

1 0.59 lb ai/A x 0.26 ≤ 0.75 lb ai/A

Page 5 of 44

### were assessed

. The occupational post

- application risks MOEs range from 110 to 2,800

.

Paclobutrazol is classified as Toxicity Category III via the dermal route and or skin irritation potential based on studies submitted in 2012. It is not a skin sensitizer. Short

- and intermediate

term post

- application risk estimates were not a concern on day 0 (12 hours following application) for all post

- applica tion activities. Under 40 CFR 156.208 (c) (2) (iii), ai’s classified as Acute Toxicity Category III chemicals require a 12

- hr restricted entry interval ( REI ) . The occupational

post

- application assessment, dermal risk estimates do not exceed HED’s level of concern (MOEs >100). Based on the acute dermal toxicity, the 12

- hour REI that appears on the current paclobutrazol labels is supported by the acute toxicity data.

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

- cancer occupational post

- app lication inhalation exposure assessment was not performed for paclobutrazol at this time. If new policies or procedures are put into place, the Agency may revisit the need for a quantitative occupational

post

- application inhalation exposure assessment for paclobutrazol

.

Review of Human Research

This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical. These data, which include studies from PHED 1.1; the AHETF datab ase; the Outdoor Residential Exposure Task Force (ORETF) database; the ARTF database; ExpoSAC Policy 14 (SOPs for Seed Treatment); the Residential SOPs (Lawns/Turf); a chemical

- specific turf transferable residue study (MRID 45214201), and a

chemical

- specif ic dislodgeable foliar residue study (MRID 45310801 and 45336601)

. are (1) subject to ethics review pursuant to 40 CFR 26, (2) have received that review, and (3) are compliant with applicable ethics requirements. For certain studies, the ethics review may have included review by the Human Studies Review Board. Descriptions of data sources, as well as guidance on their use, can be found at the Agency website 2



### .

2.0 Risk Assessment Conclusions and Recommendations

2.1 Summary of Risk Estimates

All adult and older children golfing dermal risk estimates for both liquid and granular formulations are greater than HED’s level of concern (MOEs ≥ 100). All adults on treated turf dermal risk estimates for both liquid and granular formulations MOEs range fr om 170 to 1,100.

All children 1

– 2 years old oral non

- dietary ingestion risk from hand

- to

- mouth activity on treated turf estimates for both liquid and granular formulations MOEs range from 210 to 1,400,000.

The short

- and intermediate

- term risk estimates for the occupational handler scenarios are greater

than HED’s LOC (MOEs ≥ 100) with the exception of mixing/loading/applying liquids via a backpack sprayer. The MOEs range from 29 to 19,000,000. The backpack sprayer equipment

2 http://www.epa.gov/pesticides/science/handler

- exposure

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

- app

- exposure

- data.html

Page 6 of 44

### scenario is still not greater than HED’s LOC (MOEs < 100) even with the use of personal protective equipment PPE of a double layer and gloves (MOE = 58).

The short

- and intermediate

- term risk estimates for all primary and secondary handl er scenarios are greater than HED’s LOC (MOEs ≥ 100) at varying levels of PPE

. The short

- and

intermediate

- term risk estimates for all primary and secondary handler scenarios MOEs range from 16,000 to 13,000,000.

The occupational post

- applica tion risks ar e greater than HED’s LOC (MOE s ≥ 100) on day zero after application for all post

- application activities that were assessed . The occupational post

application risks MOEs range from 110 to 2,800

.

2.2 Label Recommendations from Occupational Assessment

None.

2.3 Label Recommendations from Residential Assessment

None.

2.4 Data Deficiencies and Requirements

None.

3.0 Hazard Characterization

Paclobutrazol has low toxicity in the rat, rabbit, and guinea pig via the oral (category III) route of exposure, the dermal route (category III) in rats and rabbits, and via the inhalation route (category III to IV) in rats. It is slightly to mildly irritating to the skin and the eye and is

nega tive for dermal sensitization. T able 3.1 presents a summary of the acute toxicity information for paclobutrazol.

Acute Toxicity

Table 3. 1

. : Acute Toxicity of Paclobutrazol Technical Grade

Guideline No/Study Type MRIDs Results Toxicity Category

870.1100 Acute Oral (97% ai) Alderley Park Rat 00117478 (1983) LD 50 = 1954 mg/kg (M) 1336 mg/kg (F) III

870.1100 Acute Oral (97% ai) Alderley Park Mouse 00117478 (1982) LD 50 = 490 mg/kg (M) 1219 mg/kg (F) II

870.1100 Acute Oral (97% ai) Dunkin Hartley Albino Guinea pig 00117478 (1982) LD 50 = 542 mg/kg (M) >400 and <640 mg/kg (F) III

870.1100 Acute Oral (97% ai) 00117478 (1982) LD 50 = 835 mg/kg (M) 937 mg/kg (F) III

Page 7 of 44NZW Rabbit

870.1200 Acute Dermal (97% ai) Alderley Park Rat 00117478 (1982) LD 50 = >1000 mg/kg (M F) II

870.1200 Acute Dermal (97% ai)

NZW Rabbit 00117478 (1982) LD 50 = >1000 mg/kg (M F) II

870.1300 Acute Inhalation (97% ai)

50% ai Alderley Park Rat 00117482 (1982) LC 50 = >766 mg/m 3 (M)

359

- 766 mg/m 3 (F) III

870. 2400 Primary Eye Irritation ( 97% ai)

NZW Rabbit 00117479 (1982) 5/6 rabbits with unwashed eyes had slight corneal opacity, which cleared within 7 days; 3/6 rabbits with washed eyes

had slight redness of the conjunctiva, with some chemosis and discharge, which

was not apparent by 3 days. III a

870.2500 Primary Skin Irritation (97% ai) NZW Rabbit 00117479 (1982) Mild irritation that persisted for

72 hours III

870.2500 Primary Skin Irritation ( 97% ai) Alderley Park Albino Rat 00117479 (1982) 3/5 M showed erythema; 2/5 (F) showed desquamation and scabbing. Effects did not persist in either sex. III

870.2600 Dermal Sensitization (Guinea pig) Dunkin Hartley Albino 00117479 (1982) Not a skin sensitized

a Reclassified in 1995, based on additional data provided by the registrant (HED Document 011460).



### Toxicological PODs Used for Risk Assessment

Short

- term Dermal : Quantification of dermal risks was performed using a developmental rat study with a NOAEL of 10 mg/kg/day base d on partial ossification of the 7 th 

### vertebra and an

increased incidence of 14 th 

### rib on a fetal and litter basis at a dose that was not maternally toxic (LOAEL = 40 mg/kg/day)

. Since an oral dose was selected, a dermal absorption factor of 18.7 % should be used in estimating dermal risks

. A Margin of Exposure (MOE) of 100 is required

which includes an in terspecies extrapolation (10X) and an intrasp ecies variability (10X)

.

Short

- term Inhalation : Quantification of inhalation risks was performed using a developmental rat study with a NOAEL of 10 mg/kg/day based on partial ossification of the 7 th 

### vertebra and an

increased incidence of 14 th 

### rib on a fetal and litter basis at a dose that was not maternally toxic (LOAEL = 40 mg/kg/day)

. Si nce an oral dose was selected absorption via inhalation is presumed to be equivalent to oral absorption. A MOE of 100 is requi red which includes an in terspecies extrapolation (10X) and an intraspecies vari ability (10X)

.

Short

- term Incidental Oral : Quantification of incidental oral ingestion risks was performed using a reproductive rat study with a NOAEL of 23.2 mg/kg/day based o n the increased incidence of chromodacryorrhea, thickened eyelids and dental malocclusion, increased liver weights, mottlin g

Page 8 of 44

### or accentuation of the lobular structure of the liver along with liver enlargement, pallor and discoloration in male and female pups of both generations (Offspring LOAEL = 116.9 mg/kg/day) . A MOE of 100 is required which includes an interspecies ex trapo lation (10X) and

an intrasp ecies variability (10X)

.

HED reviewed the full toxicological database for paclobutrazol in an attempt to select endpoints for the dermal children 1 < 2 years old and 6 to < 11 years old scenarios; however no appropriate endpoint was available because in a three

- week derma l toxicity test paclobutrazol was not systemic ally toxic up to the limit dose. An inhalation endpoint for the children 1 < 2 y ears old and 6 < 11 years old scenario was not selected because there i s no exposure to them via the

inhalation route.

The need for a subchronic inhalation study for paclobutrazol was discussed by the Hazard and

Sci ence Policy Council (HASPOC) ( Leshin , 2014, TXR # 0056914 ) . The HASPOC concluded that based on a weight

- of

- evidence approach, considering all the available hazard and exposure information for paclobutrazol, a subchronic inhalation study is not needed at this time.

There are no proposed or currently registered food uses for paclobutrazol. Carcinogenicity

studies are not required for non

- food use chemicals , however, c arcinogenicity studies in mice

and rats are available. In 1994, the RfD Peer Committee evaluated the potential carcinogenicity of paclobutrazol (TXR 0011081). At that time it was determined that the Agency w as unable to determine the potential carcinogenicity of paclobutrazol because the maximum tolerated dose (MTD) was not achieved in the 2

- year carcinogenicity/chronic study in rats and the carcinogenicity/chronic study in mice. The carcinogenic potential wi ll be re

- evaluated if the use pattern changes (i.e., food uses are proposed).

The Agency’s level of concern for risks (i.e., target level for MOEs) is defined by the uncertainty factors that are applied to the assessment. The Agency typicall y applies a f actor of 10X to account for interspecies extrapolation to humans from the animal test species and another factor

of 10X to account for intra

- species sensitivity

. In the case of paclobutrazol, t he total uncertainty factor that has been applied to occupational and res idential risk assessments is 10 0 for short

- and

intermediate

- term dermal, inhalation and incidental oral exposures.

A summary of the toxicological doses and endpoints for use in the occupational and residential exposure and risk ass essment are provided in Table 3.2

.

Table 3.2

. : Summary of Toxicological Doses and Endpoints and Point s of Departure for

Paclobutrazol

Exposure/

Scenario Point of Departure Uncertainty

Factors Level of Concern for

Risk Assessment Study and Toxicological Effects

Acute Dietary General Population NOAEL = 30 mg/kg UF A =10x

UF H =10x 30 mg/kg NOAEL 100 (UF)

a RfD = 0. 3 mg/kg Acute Neurotoxicity Study (Rats)

MRID 49211902

LOAEL = 150 mg/kg, based on transient

alterations in motor activity (decreased rearing

and decreased subsession distances in females

3

- 4 hours after dosing)

Page 9 of 44

### Table 3.2

. : Summary of Toxicological Doses and Endpoints and Point s of Departure for

Paclobutrazol

Exposure/

Scenario Point of Departure Uncertainty

Factors Level of Concern for

Risk Assessment Study and Toxicological Effects

Acute Dietary

Females 13

- 49 NOAEL = 10 mg/kg/day UF A =10x

UF H =10x 10 mg/kg/day NOAEL 100 (UF)

a RfD = 0. 1 mg/kg Developmental Toxicity in Rats MRID 00143158) Developmental LOAEL = 40 mg/kg/day, based on partial ossification of the 7 th vertebra and an

increased incidence of 14 th rib on a fetal and

litter basis at a dose th at was not maternally

toxic.

Chronic Dietary All Populations NOAEL = 10.8 mg/kg/day UF A =10x

UF H =10x 10.8 mg/kg/day NOAEL 100 (UF)

cRfD = 0.11 mg/kg/day Chronic (2

- Year Rat) Feeding Toxicity MRID

40734301 LOAEL = 54.2 mg/kg/day , based on increased

liver weights (both sexes), hypertrophy, and steatosis (both sexes) and decreased triglycerides (females)

Incidental Oral

Short

- and Intermediate

Term (Young children1

- 2 years old) NOAEL =

23.2 mg/kg/day UF A =10x

UF H =10x Residential LOC = 100 Reproductive Toxicity Study in Rats

MRID 40734303/47338506 Offspring LOAEL = 116.9 mg/kg/day, based

on the increased incidence of chromodacryorrhea, thickened eyelids and dental malocclusion; increased liver weights; mottling or accentuation of the lobular structure of the liver along with liver enlargement, pallor and discoloration in male and female

pup s of both generations.

Dermal

Short

- and Intermediate

Term (Young Children 1

- 2 years old) No dermal risk assessment because in a 3

- week dermal toxicity test (MRID 00132688), paclobutrazol was not systemically toxic up to the limit dose.

Inhalation

Short

- and Intermediate

Term (Young Children 1

- 2 years old) There is no exposure to young children via the inhalation route

.

Cancer (oral, dermal, inhalation) Not required for non

- food use pesticides.

Dermal

Short

- and Intermediate

Term (Females 13

- 49) Oral NOAEL = 10 mg/kg/day

(Dermal Absorption Rate =

18.7%; (MRID

41048202) UF A =10x

UF H =10x Residential/Occupational

LOC = 100 Developmental Toxicity in Rats MRID 00143158) Developmental LOAEL = 40 mg/kg/day, based on partial ossification of the 7 th vertebra and an

increased incidence of 14 th rib on a fetal and litter basis at a dose that was not maternally

toxic.

Inhalation

Short

- and Intermediate

Term (Females 13

- 49) Oral NOAEL = 10 mg/kg/day

Inhalation Rate =

100% UF A =10x

UF H =10x Residential/Occupational

LOC = 100 Developmental Toxicity in Rats MRID 00143158) Developmental LOAEL = 40 mg/kg/day, based on partial ossification of the 7 th vertebra and an

increased incidence of 14 th rib on a fetal and

litter basis at a dose that was not maternally

toxic.

NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human population (intraspecies). MOE = margin of exposure. LOC = level of concern. Note: A FQPA factor was not applied because the currently registered use patterns are all non

- food uses.

Page 10 of 44

### Absorption

A dermal absorption factor of 18.7 % was used for the expo sure assessment and is based on a dermal penetration study . Since no inhalation absorption data are available, toxicity by the inhalation route is considered to be equivalent to the est imated toxicity by the oral route of

exposure.

Body Weight

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

4.0 Use Profile

Paclobutrazol is currently registered for use as a foliar spray to turf (including parks, athletic fields, residential lawns, and golf courses)

, ornamental plants in nurseries and greenhouses, as a tree injection, as a soil injection, as a bulb soak treatment, as pre

- plant plugs/liners, and as a seed treatment (on cucurbi t, pepper, tomato , broccoli, cauliflower, and cabbage seeds). Specific

detai ls related to the existing use pattern are s ummarized in Table 4.1

.

Table 4.1

. : Paclobutrazol Use Patterns and Formulations

Formulation Use Sites Maximum Application Rate Application Equipment REI Notes

Soluble

Concentrate Turf 0.75 lb ai/A Ground and

handheld 24 hrs or 12 hrs depending

on label Although paclobutrazol turf products do not appear to be specifically marketed towards residential handler use (i.e., homeowners); residential handler

use was assumed to be protective of any such use

Granul ar Turf 0.5 lb ai/A Ground and

handheld 12 hrs Although paclobutrazol turf products do not appear to be specifically marketed towards residential handler use (i.e., homeowners); residential handler

use was assumed to be protective of any such use

So luble

Concentrate Tree Injection (Soil injection at

base of tree) 0.352 lb ai/tree Soil injection equipment N/A

Emulsifiable

Concentrate Pre

- plant plugs/liners 0.0000 51 lb ai/gal Plug/liner soak N/A

Emulsifiable

Concentrate Bulbs 0.00255 lb ai/gal Bulb soak N/A Application rate represents highest application rate for a bulb (freesia)

Emulsifiable

Concentrate Ornamental

Plants in

Greenhouses

and Nurseries 0.59 lb ai/A Ground and

handheld 12 hours Application rate represents highest application rate for an ornamental (chrysanthemums)

Soluble

Concentrate Tree Injection (8 inch tree) 0.0099 lb ai/tree Pressurized injection system

N/A Application rates on labels are presented for multiple diameter trees; two application rates were selected to be representat ive of

those on the labels Tree Injection (35 inch tree) 0.07 lb ai/tree Pressurized injection system

Page 11 of 44Table 4.1

. : Paclobutrazol Use Patterns and Formulations

Formulation Use Sites Maximum Application Rate Application Equipment REI Notes

Soluble

Concentrate Cucurbit Seed 0.00027 lb ai/lb seed

Commercial seed treatment equipment N/A On

- farm seed treatment is prohibited Tomato Seed 0.00414 lb ai/lb seed Pepper Seed 0.00247 lb ai/lb seed

Broccoli Seed 0.000661 lb ai/seed

Cauliflower

Seed 0.000635 lb ai/seed

Cabbage Seed 0.000639 lb ai/seed

Wettable

Powder Tree Injection (6

- 16 inches in

diameter) 0.000059 lb ai/tree Pressurized injection system

N/A Application rates on labels are presented for multiple diameter trees; two application rates were selected to be representative of

those on the labels Tree Injection (>16 inches in

diameter) 0.00024 lb ai/tree Pressurized injection system



### 5.0 Residential Exposure and Risk Estimates

Paclobutrazol is currently registered for use as a foliar spray for turf (including parks, athletic fields, and golf courses). Paclobutrazol is currently not registered for homeowner use on residential lawns. Therefore, a residential handler exposure ass essment was not conducted. A residential post

- application assessment was performed as use of paclobutrazol in parks and golf courses is expected to result in residential post

- application exposure. In assessing these

exposures, HED’s 2012 Residential SOPs 3 

### for Residential Pesticide Exposure Assessment: Lawns/Turf was used. Some of the data included in the Lawns/Turf SOP are proprietary and thus are subject to the data protection provisions of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA ).

5.1 Residential Post

- application Exposure/Risk Estimates

There is the potential for post

- application exposure for individuals exposed as a result of being in an environment that has been previously treated with paclobutrazol. The quantitative exposure/risk assessment for residential post

- application exposures is based on the following

scenarios:

• Physical activities on turf: adults (dermal) and children 1 < 2 years old (incidental oral)

• Golfing: adults (dermal), children 11 < 16 years old (d ermal)

The lifestages selected for each post

- application scenario are based on an analysis provided as an Appendix in the 2012 Residential SOPs 4 

### . While not the only lifestage potentially exposed for these post

- application scenarios, the lifestage that is included in the quantitative assessment is health protective for the exposures and risk estimates for any other potentially exposed lifestage.

Residential Post

- application Exposure Data and Assumptions

3 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.html

4 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.html

Page 12 of 44

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

post

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

SOPs 5



### .

In addition, the following assumptions were used to ca lculate post

- application risk estimates:

Assumptions:

• A TTR study was used to assess the liquid formulation scenarios ( Turf Enhancer® 2SC Plant Growth Regulator Transferable Turf Residue Study

– MRID No.: 45214201). Data

were collected at three sites in the TTR study including New York, California, and North

Carolina. Data from the California site was used in this assessment as it resulted in the highest predicted Day 0 residues (see Appendix B for more details).

Application Rate: Refer to the currently registered use patter n table in Table 4.1.

Exposure Duration: Residential post

- application exposure is expected to be short

- term in duration. While multiple applications may be possible, it is anticipated that these applications

will be inter mittent in nature and dissipation due to rainfall/irrigation, grass growth, and grass mowing is expected.

Residential Post

- application Non

- Cancer Exposure and Risk Equations

The algorithms used to estimate residential post

- application exposure and dose can be found in Appendix A and/or the 2012 Residential SOPs 5



### .

Combining Exposure and Risk Estimates

The incidental oral scenarios (i.e., hand

- to

- mouth and object

- to

- mouth) should be considered

inter

- related and it is likely that they occur interspersed amongst each other across time. However, combining these scenarios would be overly

- conservative becaus e of the conservative nature of each individual assessment. Therefore, the post

- application exposure scenarios that represents the highest exposure for children 1 to < 2 years old is the hand

- to

- mouth scenario. This scenario should be considered a protec tive estimate of children’s exposure to pesticides

used outdoors.

Summary of Residential Post

- application Non

- Cancer Exposure and Risk Estimates

A summary of the adult and children short

- term dermal exposure and risk estimates is shown in

Table 5 .1.1. All adult and children golfing dermal risk estimates for both liquid and granular formulations are greater than the LOC (MOEs ≥ 100). All adults on treated turf dermal risk estimates for both liquid and granular formulations are greater than the LOC (MOE s ≥ 100).

Page 13 of 44Table 5.1.1. Residential Post

- application Non

- cancer Exposure and Risk Estimates for Paclobutrazol

Lifestage Post

- application Exposure Scenario Application Rate

a (lb ai/A) TTR (ug/cm 2 ) Dermal Dose

b (mg/kg/day) Dermal MOEs c

Liquid Formulations

Adult Dermal Physical Activities on Turf

0.75 0.080 d, 0.058 170

Golfing 0.0046 2,200

Child 11 < 16 years old Dermal Golfing 0.75 0.080 d 0.0046 2,200

Granular Formulations

Adult

Dermal Physical Activities on Turf

0.5 0.01 e 0.01 1,100

Golfing 0.0006 16,000

Child 11 < 16 years old 0.0006 16,000

a. Application rates = maximum application rates from labels.

b. Dose (mg/kg/day) equations provided in Appendix A.

c. Dermal MOE = NOAEL (10 mg/kg/day) / Dermal Dose (mg/kg/day) d. Representative of California TTR data taken from MRID No.: 45214201; the site that resulted in the highest TTR values. e. Turf Transferable Residues (TTR) = Application Rate x 0.2% x 11.2.



### A summary of the children short

- term oral non

- d ietary ingestion exposure and risk estimates is

shown in Tabl e 5 .1.2. All children oral non

- dietary ingestion risk estimates for both liquid and granular formulations do not exceed HED’s level of concern (MOEs ≥ 100).

Table 5.1.2. Short

- Term Oral Non

- dietary Ingestion Residential Post

- application Exposure and Risk Estimates for

Paclobutrazol

Lifestage Post

- application Exposure Scenario Application Rate a (lb ai/A) TTR (ug/cm 2 ) Oral Dose b (mg/kg/day) Oral

MOEs c Liquids

Child 1 < 2 year old Oral Hand

- to

- Mouth

0.75 0.080 d 0.011 2,100 Object

- to

- Mouth 0.00033 70,000

Soil Ingestion 0.000025 910,000

Granulars

Child 1 < 2 year old Oral Hand

- to

- Mouth

0.5 0.01 e 0.0008 31,000 Object

- to

- Mouth 0.00005 500,000

Soil Ingestion 0.000017 1,400,000 Episodic Granular Ingestion (1.4% ai) 0.05 210



### a. Application rates = maximum application rates from labels.

b. Dose (mg/kg/day) equations provided in Appendix A.

c. Oral MOE = NOAEL (23.2 mg/kg/day) / Oral Dose (mg/kg/day).

d. Representative of California TTR data taken from MRID No.: 45214201; the site that resulted in the highest TTR values. e. Turf Transferable Residues (TTR) = Application Rate x 0.2% x 11.2.

Page 14 of 44

### 5.3 Residential Risk Estimates for Use in Aggregate Assessment

Table 5

. 3 reflects the residential risk estimates that are recommended for use in the aggregate assessment for paclobutrazol.

• The recommended residential exposure for use in the adult short

- term aggregate assessment reflects dermal exposure from post

- appl ication exposure from physical

activities on turf.

• The recommended residential exposure for use in the children 1 to <2 years old short

term aggregate assessment reflects hand

- to

- mouth exposures from post

- application exposure to turf applications.

Table 5

. 3 . Recommendation for the Residential Exposures for the Paclobutrazol Aggregate Assessment

Lifestage Exposure

Scenario Dose (mg/kg/day) 1 MOE 2

Dermal Inhalation Oral Total Dermal Inhalation Oral Total

Adult Turf

(Liquids) 0.058 N/A N/A 0.058 170 N/A N/A 170

Child 1 to <2 yrs old Hand

- to

Mouth

(Liquids) N/A N/A 0.011 0.011 N/A N/A 2,100 2,100

1 Dose = the highest dose for each applicable lifestage of all residential scenarios assessed. Total = dermal + inhalation + i ncidental oral (where applicable).

2 MOE = the MOEs associated with the highest residential doses. Total = 1 ÷ (1/Dermal MOE) + (1/Inhalation MOE) + (1/Incidenta l Oral MOE), where applicable.



### 5.4 Spray Drift

Off

- target movement of pesticides can occur via many types of pathways and it is governed by a
variety of factors. Sprays that are released and do not deposit in th e application area end up off

t rget and can lead to exposures to those it may directly contact. They can also deposit on surfaces

where contact with resi dues can eventually lead to indirect exposures ( e.g. , children playing on
lawns where residues have deposited next to treated fields). The potential risk estimates from
these residues can be calculated using drift modeling coupled with methods employed for
residential risk assessments for turf products.

The approach to be used for quantitatively incorporating spray drift into risk assessment is based
on a premise of compliant applications which, by definition, should not result in direct exposures

to indivi duals because of existing label language and other regulatory requirements intended to
prevent them. 5 

### Direct exposures would include inhalation of the spray plume or being sprayed
directly. Rather, the exposures addressed here are thought to occur indire ctly through contact
with impacted areas, such as residential lawns, when compliant applications are conducted.
Given this premise, exposures for children (1 to 2 years old) and adults who have contact with
turf where residues are assumed to have deposite d via spray drift thus resulting in an indirect

5 

### This approach is consistent with the requirements of the EPA’s Worker Protection Standard which,

when in cluded on all labels, precludes direct exposure pathways.

Page 15 of 44

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

considered in risk assessment.

Several paclobutrazol products have existing labels for use on turf, thus it was consid ered
whether the risk assessment for that use may be considered protective of any type of exposure
that would be associated with spray drift. The currently registered maximum single application
rate of paclobutrazol for foliar sprays on ornamentals in nur series is 0.59 lb ai/A which is less
than the direct turf application rate of 0.75 lbs ai/A, therefore the registered residential uses on
turf result in exposure greater than potential exposure from spray drift; and no new spray drift

residential assessment needs to be completed. The turf post

- appli cation MOEs are protective for
any potential exposures related to spray drift for paclobutrazol

.

5.5 Residential Bystander Post

- Application Inhalation Exposure

Volatilization of pesticides may be a s ource of post

- application inhalation exposure to individuals nearby pesticide applications. The agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act

Scientific Advisory Panel (SAP) in December 2009, and received the SAP’s final report on March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The agency has evaluated the SAP report and has developed a Volatilization Screening Tool and a subsequent Volatilization Screening Analysis ( http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

- OPP

- 2014

- 0219 ). During Registration Review, the agency will utilize thi s analysis to determine if data (i.e., flux studies, route

- specific inhalation toxicological studies) or f urther analysis is required for paclobutrazol

.

6.0 Occupational Exposure and Risk Estimates

6.1 Occupational Handler Exposure/Risk Estimates

HED uses the term handlers to describe those individuals who are involved in the pesticide application process. HED believes that there are distinct job functions or tasks related to applications and exposures can vary depending on the specifics of each t ask. Job requirements (amount of chemical used in each application), the kinds of equipment used, the target being treated, and the level of protection used by a handler can cause exposure levels to differ in a manner specific to each application event.

Based on the anticipated use patterns and current labeling, types of equipment and techniques that can potentially be used, occupational handler dermal and inhalation exposure is expected

from the existing uses.

The quantitative exposure/risk assessme nt developed for occupational handlers is based on the following scenarios:

Page 16 of 44

### • Mixing/loading liquids for groundboo m applications

• Mixing/loading liquids for tree injection

• Mixing/loading liquids for soil injection

• Mixing/loading wettable powders for tree injections

• L oading granules for open cab solid broadcast spreader applications

• Mixing/loading liquid concentrations via dip (bulb soak) /liner soaks

• Applying sprays for open cab groundboom equipmen t

• Applying granules for open cab solid broadcast spreader

• Lo ading/applying granules for belly grinder applications

• Loading/applying granules for pus h type spreader applications

• Mixing/loading/applying liquids for backpack sprayer applications

• Mixing/loading/applying liquids for manually pressurized handwand applica tions

• Mixing/loading/applying liquids for mechanically pressurized handgun sprayer applications

Occupational Handler Exposure Data and Assumptions

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

handler risk assessments. Each assumption and factor is detailed below on an individual basis.

Application Rate : Refer to the currently registered use pattern table in Section Table 4.1

.

Unit Exposures: It is the policy of HED to use the best available data t o assess handler exposure. Sources of generic handler data, used as surrogate data in the absence of chemical

- specific data, include PHED 1.1, the AHETF database, the Outdoor Residential Exposure Task Force (ORETF) database, or other registrant

- submitted occupational exposure studies. Some of these data are proprietary (e.g., AHETF data), and subject to the data protection provisions of FIFRA. The standard values recommended for use in predicting handler exposure that are used in this assessment, known a s “unit exposures”, are outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table 6 

### ”, which, along with additional information on HED policy on use of surrogate data, including descriptions of the various sources, can be found at the Agency website 7



### .

Area Treated or Amount Handled:

The daily areas treated or amounts handled were defined for each handler scenario (in appropriate units) by determining the amount that can be reasonably treated by an individual in a single day. When possible, the assumptions for daily areas treated or amounts handled are taken from the HED’s ExpoSAC Policy #9 .1 : “Standard Values for Daily Acres Treated in Agriculture”. Values used for area treated or amount handled include :

• 40 acres for groundboo m application for golf courses and nurseries ;

• 4 0 acres for tractor drawn spreader application for golf courses ;

6 Available: http://www.epa.gov/opp00001/science/handler

- exposure

- table.pdf

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

- exposure

- data.html

Page 17 of 44

### • 50 trees/day for tree inject ion applications (see note below) ;

• 5 0 trees/day for soil injection applications (see note below) ;

• 100 and 1000 gallons for mixing/loading liquids concentrations via dip (bulb soak) /liner

soaks ;

• 5 acres for mixing/loading/applying with a mechanica lly pressurized handgun sprayer to turf and golf courses and 25 acres to nurseries and greenhouses ;

• 5 acres for mixing/loading/applying with a ma nually pressurized h andwand to nurseries and greenhouses ;

• 5 acres for mixing/loading/ap plying with a backpack sprayer to turf, golf courses, nurseries, and greenhouses ; and

• 5 acre s for push

- type spreader application to t urf and golf courses

.

Note: HED received written information from several paclobutrazol registrants that for occupational applicators, about 50 trees per day are treated for tree injection applications and soil injection applications. The data ranged from 10 trees per day to 70 trees per day . HED selected 50 trees per day for tree and soil injection applications because it wa s the most typical number

from the available information

.

Exposure Duration:

HED classifies exposures from 1 to 30 days as short

- term and exposures 30 days to six months

as intermediate

- term. Exposure duration is determined by many things, including the exposed population, the use site, the pest pressure triggering the use of the pesticide, and the cultural practices surrounding that use site. For most agricultural uses, it is reasonable to believe that occupational handlers will not apply the same chemical every day for more than a one

- month time frame; however, there may be a la rge agribusiness and/or commercial applicators who may apply a product over a period of weeks (e.g., completing multiple applications for multiple clients within a region).

For paclobutrazol , based on the proposed use, short

- and intermediate

- term expos ures are expected. The short

- and intermediate

- term PODs are the same; therefore, short

- term risk estimates are protective of longer

- term exposures.

Mitigation/Personal Protective Equipment: Estimates of dermal and inhalation exposure were calculated for various levels of personal protective equipment (PPE). Results are presented for “baseline,” defined as a single layer of clothing consisting of a long sleeved shirt, long pants, shoes plus s ocks, no protective gloves, and no respirator, as well as baseline with various levels

of PPE as necessary (e.g., gloves, respirator, etc). The paclobutrazol product labels direct mixers, loaders, applicators and other handlers to wear long

- sleeved shirt and long pants,

chemical

- resistant gloves, and shoes plus socks. In addition, some of the labels also state that

chemical

- resistant aprons should also be used.

Occupational Handler Non

- Cancer Exposure and Risk Estimate Equations

The algorithms used to estimate non

- cancer exposure and dose for occupational handlers can be found in Appendix A.

Page 18 of 44

### Combining Exposures/Risk Estimates:

Dermal and inhalation risk estimates were combined in this assessment, since the toxicological effects for these exposure rou tes were similar. Dermal and inhalation risk estimates were combined using the following formula:

Total MOE = 1 ÷ (1/Dermal MOE) + (1/Inhalation MOE)



### Summary of Occupational Handler Non

- Cancer Exposure and Risk Estimates

The short

- and intermediate

- term risk estimates for occupational handlers are included in Table

6 .1.1. The short

- and intermediate

- term risk estimates for the occupational handler scenarios are greater than HED’s LOC (MOEs ≥ 100) with the exception of mixi ng/loading/applying liquids via a backpack sprayer. The backpack sprayer equipment scenario is still not greater than HED’s

LOC (MOEs < 100) even with the use of PPE of a double layer and gloves (MOE = 58).

Page 19 of 44

### Table 6 .1.1. Occupational Handler Exposures and Risks for Paclobutrazol Turf, Ornamental, and Tree Uses

Activity Use Site PPE

- G Dermal Unit Exposure (mg/lb ai) a Baseline

Inhalation Unit Exposure (mg/lb ai) a Application

Rate b Area

Treated Daily c PPE

- G Baseline Inhalation Total MOE (PPE

- G + Baseline Inhalation) Dermal

Dose (mg/kg/day) d MOE f Dose (mg/kg/day) e MOE g

Mixer/Loader

Mixing/Loading Liquids Groundboom Applications on Ornamentals in

Nurseries

0.0376 0.000219 0.59 lb ai/A 40 A 0.0024 4,200 0.000075 130,000 4,000

Groundboom Applications on

Golf Courses 0.75 lb ai/A 40 A 0.0031 3,300 0.000095 110,000 3,200

Tree Injection (8

diameter Inch Trees) 0.0099 lb

ai/tree 50 trees 0.00005 200,000 0.0000016 6,400,000 190,000

Tree Injection (35

diameter Inch Trees) 0.07 lb

ai/tree 50 trees 0.00036 28,000 0.000011 900,000 27,000

Tree Soil Injection 0.352 lb

ai/tree 50 trees 0.0018 5,600 0.000056 180,000 5,400

Dips for Plug/Liner Soaks 0.000051 lb ai/gal 100 gals 0.00000052 19,000,000 1.60E

- 08 620,000,000 19,000,000

0.000051 lb ai/gal 1000 gals 0.0000052 1,900,000 1.60E

- 07 62,000,000 1,900,000

Dips for Bulb Soaks (Freesia) 0.00255 lb ai/gal 100 gals 0.000026 380,000 8.1E

- 07 12,000,000 370,000

0.00255 lb

ai/gal 1000 gals 0.00026 38,000 0.0000081 1,200,000 37,000

Mixing/Loading Wettable

Powders Tree Injection (6

- 16 inches in diameter) 0.17 0.043 0.000059 lb

ai/tree 50 trees 0.0000014 7,400,000 0.0000018 5,400,000 3,100,000

Tree Injection (>16 inches in

diameter) 0.00024 lb

ai/tree 50 trees 0.0000055 1,800,000 0.0000075 1,300,000 770,000

Page 20 of 44

### Table 6 .1.1. Occupational Handler Exposures and Risks for Paclobutrazol Turf, Ornamental, and Tree Uses

Activity Use Site PPE

- G Dermal Unit Exposure (mg/lb ai) a Baseline

Inhalation Unit Exposure (mg/lb ai) a Application

Rate b Area

Treated Daily c PPE

- G Baseline Inhalation Total MOE (PPE

- G + Baseline Inhalation) Dermal

Dose (mg/kg/day) d MOE f Dose (mg/kg/day) e MOE g

Loading Granulars Tractor Drawn Spreader Applications on

Golf Courses 0.0069 0.0017 0.5 lb ai/A 40 A 0.00037 27,000 0.00049 20,000 12,000

Applicator

Applying Liquid Sprays

via Groundboom Golf Courses

0.0161 0.00034 0.75 lb ai/A 40 A 0.0013 7,600 0.00015 68,000 6,900

Ornamentals in

Nurseries 0.59 lb ai/A 40 A 0.001 9,700 0.00012 86,000 8,700

Applying Granulars via Tractor Drawn Spreader Golf Courses 0.0072 0.0012 0.5 lb ai/A 40 A 0.00039 26,000 0.00035 29,000 14,000

Mixer/Loader/Applicator

Mixing/Loading/Applying Liquids via Backpack Sprayer Turf

8.26 0.00258 0.75 lb ai/A 5 A 0.084 120 0.00014 71,000 120

Golf Course 0.75 lb ai/A 5 A 0.084 120 0.00014 71,000 120

Drench Tree Treatments (8 inch Tree) 0.07 lb

ai/tree 50 trees 0.078 130 0.00013 76,000 130

Drench Tree Treatments (35

inch Tree) 0.31 lb

ai/tree 50 trees 0.35 29 0.00058 17,000 29

Drench Tree

Treatments (35 inch Tree) 4.12 (PPE G

- DL) 0.00258 0.31 lb

ai/tree 50 trees 0.17 58 0.00058 17,000 58 (PPE G

- DL + baseline Inhalation)

Foliar Sprays on

Ornamentals in

Nurseries and

Greenhouses 11200 140 0.00423 lb ai/gallon 40 gallons 0.00515 1,900 0.000343 29,000 1,800

Mixing/Loading/Applying Liquids via Manually

Pressurized Handwand Foliar Sprays on

Ornamentals in

Nurseries and

Greenhouses 0.43 30 0.00423 lb ai/gallon 40 gallons 0.000197 51,000 0.0000736 140,000 37,000

Drench Tree Treatments (8 inch Tree) 0.07 lb

ai/tree 50 trees 0.0041 2,500 0.0015 6,600 1,800

Page 21 of 44

### Table 6 .1.1. Occupational Handler Exposures and Risks for Paclobutrazol Turf, Ornamental, and Tree Uses

Activity Use Site PPE

- G Dermal Unit Exposure (mg/lb ai) a Baseline

Inhalation Unit Exposure (mg/lb ai) a Application

Rate b Area

Treated Daily c PPE

- G Baseline Inhalation Total MOE (PPE

- G + Baseline Inhalation) Dermal

Dose (mg/kg/day) d MOE f Dose (mg/kg/day) e MOE g

Drench Tree Treatments (35

inch Tree) 0.31 lb

ai/tree 50 trees 0.018 550 0.0067 1,500 400

Loading/Applying

Granulars via Push

- type Spreader Turf

0.24 0.01 0.5 lb ai/A 5 A 0.0016 6,100 0.00036 28,000 5,000

Golf Course 0.5 lb ai/A 5 A 0.0016 6,100 0.00036 28,000 5,000

Mixing`/Loading/Applying Liquids via Mechanically

Pressurized Handwand Turf 0.88 0.0019 0.75 lb ai/A 5 A 0.0089 1,100 0.0001 97,000 1,100

Golf Course 0.75 lb ai/A 5 A 0.0089 1,100 0.0001 97,000 1,100 Foliar Sprays on

Ornamentals in

Nurseries 390 3.9 0.00423 lb ai/gallon 1,000 gallons 0.00447 2,200 0.000239 42,000 2,100

Foliar Sprays on

Ornamentals in

Greenhouses 2,500 120 0.00423 lb ai/gallon 1,000 gallons 0.0287 350 0.00736 1,400 280

a. Unit Exposures taken from Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (http://www.epa.gov/opp 00001/science/handler

- exposure

- table.pdf)

b. Application rates = maximum application rates from labels. c. Exposure Science Advisory Council Policy #9.1. d. Dermal Dose (mg/kg/day) = Dermal Unit exposure (mg/lb ai) × Conversion Factor (0.001 mg/μg) x Application Rate x Area Tre ated or Amount Handl ed x % Dermal Absorption Factor (18.7%) /Body weight (69 kg).

e. Inhalation Dose (mg/kg/day) = Inhalation Unit Exposure (mg/lb ai) x Conversion Factor (0.001 mg/μg) x Application Rate x Area Treated x %Absorption (100% inhalatio n ) / Body weight (69 kg).

f. Dermal MOE = Dermal NOAEL (10 mg/kg/day) / Dermal Dose (mg/kg/day). LOC = 100. g. Inhalation MOE = Inhalation NOAEL (10 mg/kg/day) / Inhalation Dose (mg/kg/day). LOC = 100

Page 22 of 44

### Short

- /Intermediate

- Term Handler Risk for Seed Tre atments

Paclobutrazol is currently registered for commercial seed treatment use on tomato, pepper, and cucurbit, broccoli, cauliflower, and cabbage se eds . The paclobutrazol labels do not permit on

farm seed treatment. Based on the existing seed treatment use pattern, t here is a potential for exposure to paclobutrazol to primary handlers (i.e., activities related to treating the seed) and secondary handlers (i.e., planting treated seed). Primary and secondary handler exposure is expected to be sh ort

- or intermediate

- term in duration based on the information provided on the existing label s

. The short

- and intermediate

- term toxicological endpoints are the same for the respective routes of exposure; therefore, the estimates of risk for short

- term du ration exposures are protective of those for intermediate

- term durations.

Primary Handler (Treating Seed)

Potential primary occupational handler exposure scenarios from the use of paclobutrazol as a commercial seed treatment include:

• Mixing, loading, applying liquid formulations;

• Bagging treated seed;

• Sewing bags; and

• Multiple activities.

Typically, for large

- scale commercial seed treatments, workers perform only those specific individual tasks listed above; however, it is assumed that workers also ma y perform multiple activities throughout the day. As a result a “multiple activities” scenario (i.e. where one worker performs all seed treatment tasks such as loading/applying, sewing, bagging, cleaning, calibration, repair, forklif t driver, etc.) was addressed. No assessment was performed for on

farm seed treatment as the paclobutrazol labels do not permit on

- farm seed treatment.

Secondary Handler (Planting Treated Seed)

Potential secondary occupational handler exposure scenari os from the use of paclobutrazol as a commercial seed treatment include planting treated seed.

It is the policy of HED to use the best available data to assess handler exposure. Sources of generic handler data for seed treatment are incorporated in HED E xpoSAC Policy 14: SOPs for Seed Treatment. The amount of active ingredient handled depends on the application rate (lb ai/lb seed or lb ai/seed), the pounds of seed treated in a day, and the pounds of seed that can be planted in a day, all of which vary d epending upon the seed type. Values for the amount of seed treated and planted per day were obtained from HED ExpoSAC Policy 15.

Summaries of the risk estimates for primary and secondary h andlers are included in Tables 6.1.2

and 6 .1.3

. The short

- and intermediate

- term risk estimates for all primary and secondary handler scenarios are greater than HED’s LOC (MOEs ≥ 100) at some level of PPE

.

Page 23 of 44Table 6.1.2 Summary of Short

- and Intermediate

- Term Handler Exposures and Risks for Paclobutrazol Seed Treatment

Seed Type Max Application

Rate a Unit Exposure b (mg/lb ai) Amount of Seed

Treated c Absorbed Dose (mg/kg/day) d MOE e

lb ai/lb seed Dermal Inhal. lb seed/day Dermal Inhal. Dermal Inhal.
LOADER/APPLICATOR (single layer, gloves)

Cu curbit (Cucumber) 0.000229

0.00023 0.00034 3,000 0.000043 0.000003 230,000 3,000,000

Cucurbit (Cantaloupe) 0.00027 0.000050 0.000004 200,000 2,500,000

Cucurbit (Pumpkin) 0.000107 0.000020 0.000002 500,000 6,300,000

Cucurbit (Squash) 0.000172 0.000032 0.000003 310,000 3,900,000

Cucurbit (Watermelon) 0.000157 0.000029 0.000002 340,000 4,300,000

Pepper 0.00247 0.000462 0.000037 22,000 270,000

Tomato 0.00414 0.000774 0.000061 13,000 160,000

Broccoli 0.000661 0.000124 0.000010 81,000 1,000,000

Cauliflower 0.000635 0.000119 0.000009 84,000 1,1 00,000

Cabbage 0.000639 0.000119 0.000009 84,000 1,1 00,000
SEWER (single layer, no gloves)

Cucurbit (Cucumber) 0.000229

0.0062 0.00023 3,000 0.000012 0.000002 870,000 4,400,000

Cucurbit (Cantaloupe) 0.00027 0.000014 0.000003 730,000 3,700,000

Cucurbit (Pumpkin) 0.000107 0.000005 0.000001 1,900,000 9,300,000

Cucurbit (Squash) 0.000172 0.000009 0.000002 1,200,000 5,800,000

Cucurbit (Watermelon) 0.000157 0.000008 0.000002 1,300,000 6,400,000

Pepper 0.00247 0.000125 0.000025 80,000 400,000

Tomato 0.00414 0.000209 0.000041 48,000 240,000

Broccoli 0.000661 0.000033 0.000007 300,000 1,500,000

Cauliflower 0.000635 0.000032 0.000006 310,000 1,600,000

Page 24 of 44Table 6.1.2 Summary of Short

- and Intermediate

- Term Handler Exposures and Risks for Paclobutrazol Seed Treatment

Seed Type Max Application

Rate a Unit Exposure b (mg/lb ai) Amount of Seed

Treated c Absorbed Dose (mg/kg/day) d MOE e

lb ai/lb seed Dermal Inhal. lb seed/day Dermal Inhal. Dermal Inhal.
Cabbage 0.000639 0.000032 0.000006 310,000 1,600,000 BAGGER (single layer, no gloves)

Cucurbit (Cucumber) 0.000229

0.0091 0.00016 3,000 0.000017 0.000002 590,000 6,300,000

Cucurbit (Cantaloupe) 0.00027 0.000020 0.000002 500,000 5,300,000

Cucurbit (Pumpkin) 0.000107 0.000008 0.000001 1,300,000 13,000,000

Cucurbit (Squash) 0.000172 0.000013 0.000001 790,000 8,400,000

Cucurbit (Watermelon) 0.000157 0.000012 0.000001 860,000 9,200,000

Pepper 0.00247 0.000183 0.000017 55,000 580,000

Tomato 0.00414 0.000306 0.000029 33,000 350,000

Broccoli 0.000661 0.000049 0.000005 200,000 2,200,000

Cauliflower 0.000635 0.000047 0.000004 210,000 2,300,000

Cabbage 0.000639 0.000047 0.000004 210,000 2,2 00,000

MULTIPLE ACTIVITIES (combination of loader/applicator with gloves and no coveralls, sewer without gloves, stacker without gloves)

Cucurbit (Cucumber) 0.000229

0.042 0.0016 3,000 0.000078 0.000016 130,000 630,000

Cucurbit (Cantaloupe) 0.00027 0.000092 0.000019 110,000 530,000

Cucurbit (Pumpkin) 0.000107 0.000037 0.000007 270,000 1,300,000

Cucurbit (Squash) 0.000172 0.000059 0.000012 170,000 840,000

Cucurbit (Watermelon) 0.000157 0.000054 0.000011 190,000 920,000

Pepper 0.00247 0.000843 0.000172 12,000 58,000

Tomato 0.00414 0.001414 0.000288 7,100 35,000

Broccoli 0.000661 0.000226 0.000046 44,000 220,000

Cauliflower 0.000635 0.000217 0.000044 46,000 230,000

Cabbage 0.000639 0.000218 0.000044 46,000 22 0,000

Page 25 of 44a Application Rates based on existing labels for paclobutrazol.

b Unit Exposures from HED Exposure Science Advisory Council Policy 14.

c HED default for lb seed treated per day from HED Exposure Science Advisory Council Policy 15.

d Dermal Dose (mg/kg/day) = dermal unit exposure (mg/ lb ai) x application rate (lb ai/lb seed) x amount treated (lb see d/day) x absorption factor (18.7 %) / body weight (69 kg

adult). Dermal MOE = NOAEL (10.0 mg/kg/day for short

- and i ntermediate

- term exposure) / Dermal Dose (mg/kg/day). Level of concern = 100.

e Inhalation Dose (mg/kg/day) = inhalation unit exposure (mg/ lb ai) x application rate (lb ai/lb seed) x amount treated (lb seed/day) x absorption factor (100%) / body weight (69

kg adult). Inhalation MOE = NOAEL (10 .0 mg/kg/day for short

- and intermediate

- term exposure) / Inhalation Dose (mg/kg/day). Level of concern = 100.

Table 6 .2.3 . Summary of Secondary Handler (Planter) Exposures and Risks for Paclobutrazol (Single L ayer, Gloves during Loading Only)

Seed Type Max Application

Rate a (lb ai/lb

seed) Dermal Unit Exposure b (mg/lb ai) Inhalation Unit Exposure b
(m g/lb ai) Amount

of Seed

Planted

Per Day c

(lb

seed/day) Absorbed

Dermal

Dose d (mg/kg/day) Absorbed

Inhalation

Dose d (mg/kg/day) Dermal

MOE e Baseline

Inhalation

MOE e

Cucurbit Seed

(Cucumber) 0.000229 0.25 0.003 4 3,000 0.00046547 0.0000339 21, 000 300, 000

Cucurbit Seed (Cantaloupe) 0.00027 0.25 0.003 4 3,000 0.00054880 0.0000399 18,00 0 250, 000

Cucurbit Seed

(Pumpkin) 0.000107 0.25 0.003 4 3,000 0.00021749 0.0000158 46, 000 63 0

, 000

Cucurbit Seed

(Squash) 0.000172 0.25 0.003 4 3,000 0.00034961 0.0000254 29,000 390,000

Cucurbit Seed (Watermelon) 0.000157 0.25 0.003 4 3,000 0.00031912 0.0000232 31, 000 430,000

Pepper 0.00247 0.25 0.0034 3,000 0.00502054 0.0003651 2,000 27,000

Page 26 of 44Tomato 0.00414 0.25 0.003 4 3,000 0.00841500 0.0006120 1,20 0 16,000

Broccoli 0.000661 0.25 0.003 4 3,000 0.00134355 0.0000977 7,400 100, 000

Cauliflower 0.000635 0.25 0.003 4 3,000 0.00129071 0.0000939 7,70 0 110, 000

Cabbage 0.000639 0.25 0.003 4 3,000 0.001298837 0.0000945 7,700 110,000

a Application Rates based on existing labels for paclobutrazol. b Unit Exposures from HED Exposure Science Advisory Council Policy 14: Standard Operating Procedures for Seed Treatment

. c HED default for lb seed planted per day from HED Exposure Science Advisory Council Interim Policy 15 and the BEAD memo “Ac res Planted Per Day and Seeding Rates of

Crops Grown in the United States” (J. Becker, March 2011)

. d Daily Absorbed Dose (mg/ kg/day) = daily unit exposure (mg/ lb ai) x application rate (lb ai/lb seed) x amount treated (lb see d/day) x absorption factor (18.7% for dermal, 100%

for inhalation ) / body weight (69 kg a dult). Level of concern = 10 0

.

e MOE = NOAEL ( dermal and inhalation = 10 .0 mg/kg/day for short

- and intermedi ate

- term exposure) /Absorbed Dose (mg/k g/day). Level of concern = 100

.

Page 27 of 44

### 6.2 Occupational Post

- application Exposure/Risk Estimates

HED uses the term post

- application to describe exposures that occur when individuals are present in an environment that has been previously treated with a pesticide (also referred to as 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 acti vity, the nature of the crop or target that was treated, the type of pesticide application, and the chemical’s degradation properties. In addition, the timing of pesticide applications, relative to harvest activities, can greatly reduce the potential for post

- application exposure.

6.2.1 Occupational Post

- application Inhalation Exposure/Risk Estimates

There are multiple potential sources of post

- application inhalation exposure to individuals performing post

- application activities in previously treated fields. These potential sources include volatilization of pesticides and resuspension of dusts and/or particulates that contain pesticides. The agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insect icide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP’s final report on March 2, 2010 ( http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html ). The agency has evaluated the SAP report and has developed a Volatilization Screening Tool and a subsequent Volatilization Screening Analysis ( http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

OPP

- 2014

- 0219 ). During Registration Review, the agency will utilize this analysis to determine if data (i.e., flux studies, route

- specific inhalation toxicological studies) or f urther analysis is required for paclobutrazol

.

In addition, the Agency is continuing to evaluate the available post

- application inhalation exposure data generated by the Agricultural Reentry Task Force. Given these two efforts, the Agency will continue to identify the need for and, subsequently, the way to incorporate occupational post

- application inhala tion 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/commercial

handlers. 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 occupational post

- appl ication inhalation exposure scenarios.

The Worker Protection Standard for Agricultural Pesticides contains requirements for protecting workers from inhalation exposures during and after greenhouse applications through the use of ventilation requirements. [40 CFR 170.110, (3) (Restrictions associated with pesticide applications)]

.

Page 28 of 44

### A post

- application inhalation exposure assessment is not required as exposure is expected to be negligible. Seed treatment assessments provide quantitative inhalation exposure a ssessments for seed treaters and secondary handlers (i.e., planters). It is expected that these exposure estimates would be protective of any potential low

- level post

- application inhalation exposure that could result from these types of applications.

6.2 .2 Occupational Post

- application Dermal Exposure/Risk Estimates

Occupational Post

- application Dermal Exposure Data and Assumptions

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

post

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

basis.

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

- term and exposures 30 days to six mo nths as intermediate

- term. For paclo butrazol, based on the curr ently registered use, short

- and intermediate

- term expo sures are expected. The short

- and intermediate

- term PODs are the same; therefore, short

- term risk estimates are protective of longer

- term exposures.

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 ARTF exposure monitoring studies, and, as proprietary data, are s ubject to the data protection provisions of FIFRA. The standard values recommended for use in predicting post

- application exposure that are used in this assessment, known as “transfer coefficients”, are presented in the ExpoSAC Policy 3 8 

### ” which, along with additional information about the ARTF data, can be found at the Agency website 9 

### . Table 6.2.2.1 provides a summary of the anticipated post

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

Table 6.2.2.2. provides a summary of the transfer coefficients and activities associated with turf and ornamentals in greenhouse and nurseries

.

Table 6.2.2.1 . Post

- application Activities and Dermal Transfer Coefficients.

Crops Crop Height Foliage
Density Transfer Coefficients

(cm 2 /hr) Activities

Turf Low Full 2,500 Golf course maintenance,
greens only

Turf Low Full 3,700 Maintenance

Ornamentals in

Nurseries Low Min 230 Grafting, Propagating,
Transplanting

Low Full 230 Hand harvesting, Hand
pruni ng, Scouting, Hand
Weeding , T ransplanting,
Pinching, Tying/Training

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

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

- app

- exposure

- data.html

Page 29 of 44Table 6.2.2.1 . Post

- application Activities and Dermal Transfer Coefficients.

Crops Crop Height Foliage
Density Transfer Coefficients

(cm 2 /hr) Activities

High Min 230 Hand harvesting, Hand
pruning, Transplanting

High Full 230 Hand harvesting, Hand
pruning, Sc outing,
Container Moving, Hand

w eeding, Transplanting,
Pinching
Low/High Full 1900 Hand set irrigation

Ornamentals in

Greenhouses Low Min

230 Grafting, Propagating,
Transplanting

Low Full Hand harvesting, Hand
pruni ng, Scouting, Hand
weeding, Transp lanting,
Pinching, Tying/Training
High Min Hand harvesting, Hand
pruning, Transplanting
High Full Hand harvesting, Hand
pruning, Scouting,
Container Moving, Hand
weeding, Transplanting,
Pinching



### Application Rate:

• Application Rate = 0. 75 lb ai/A for turf

• Application Rate = 0. 13 lb ai/A for poinsettas

• Application Rate = 0.59 lb ai/A for chrysanthemums

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

In addition, the following assumptions and data were used in the paclobutrazol dermal post

application assessment:

• Chemical

- specific TTR data submitted in support of the paclobutrazol turf uses (MRID 45214201) . In the study, Turf Enhancer 2SC Plant Growth Regulator was applied to turf at three test sites located in Madera, California, North Rose, New York, and Creedmo or, North Carolina. Each test site consisted of one untreated control plot (containing 50 subplots) and one treated plot (containing 60 subplots). The first application was made at an application rate of 0.5 lb ai/A and the remaining applications were ma de at 0.75 lb ai/A. The turf application was made in California with a 60

- gallon tank pressure sprayer. The turf application was made in New York with a 30

- gallon cone shaped tank with a

commercial tractor

- mounted boom. The turf application was made in N orth Carolina

with a commercial tractor

- mounted sprayer equipped with a 5

- foot boom. The Modified California Roller technique was used to evaluate the amount of transferable residues from

Page 30 of 44

### turf grass. For the California test site, the average paclobutrazo l TTR value was 0.0821 ug/cm 2 

### following the third application. The residues dropped below the level of detection fourteen days after treatment, third application. For the New York test site, the average paclobutrazol TTR value was 0.0212 ug/cm 2 

### following the third application. The residues dropped below the level of detection eight days after treatment three. For the North Carolina test site, the average paclobutrazol TTR value was 0.156 ug/cm 2


### following the fourth application. The residues dropped bel ow the level of detection

twenty

- two days after treatment four. The TTR level used in this assessment (0.080 ug/cm 2 

### ) is based on the California data as it resulted in the highest predicted Day 0

residues

. Appendix B has more specific information regardin g the TTR study.

• Chemical

- specific dislodgeable foliar residue ( DFR ) data submitted in support of the paclobutrazol poinsettia uses (MRID 45336601). In the study, BONZI Ornamental Growth Regulator was applied to chrysanth emums in a greenhouse. A single application was made to chrysanthemums in separate greenhouses by a hand

- held boom powered by

CO 2 

### . Leaf discs were collected using a Birkestrand 1.784 cm (0.702 inch) diameter leaf punch. The average total paclobutrazol DFR on chrysanthemums was 0 .755 ug/cm 2



### twenty

- four hours after the application. By day thirty

- five, the average total paclobutrazol residues declined to 0.202 ug/cm 2 

### . The DFR values did not drop below the limit of quantitation (0.005 ug/cm 2 

### ) during the timeframe of the study. App endix B has more specific information regarding this DFR study.

• Chemical

- specific D F R data submitted in support of the chrysanthemum uses (MRID 45310801). In this study, Bonzi Ornamental Growth Regulator was applied to poinsettias

in shadehouses . Three a pplications were made to poinsettias at 7

- day intervals in a commercial shadehouse in Stuart, Florida. The three applications were made at a rate of 0.13 lb ai/Acre with a backpack sprayer with a hand

- held boom powered by CO 2 

### . The

field trial consisted o f one treated plot and one untreated plot. Leaf discs were collected using a Birkestrand 2.54 cm (1 inch) diameter leaf punch. The average total paclobutrazol DFR value on poinsettias was 0.439 ug/cm 2 

### after the third (final) application. By thirty

- five days after the last application, the total paclobutrazol residue declined to <LOQ (0.005 ug/cm 2 

### ). Appendix B has more specific information regarding this DFR study.

Daily dermal exposures were calculated on each post

- application day after application using the following equation:

DE (t) 

### (mg/day) = (TR (t) 

### (μg/cm 2 

### ) x TC (cm 2 

### /hr) x Hr/Day)/1000 (μg/mg)

Where:

DE(t) = Daily exposure or amount deposited on the surface of the skin at time (t) attributable for activity in a previously treated area, also referred to as potential dose (mg ai/day); TR(t) = Transferable residues that can be dislodgeable foliar residue at time “t” ( μ g/cm 2 

### );

TC = Transfer Coefficient (cm 2 

### /hour); and Hr/day = Exposure duration meant to represent a typical workday (hours).

Page 31 of 44

### Occupational Post

- application Non

- Cancer Dermal Exposure and Risk Estimate Equations

The algorithms used to estimate non

- cancer exposure and dose for occupational post

- application workers can be found in Appendix A.

Occupational Post

- application Non

- Cancer Dermal Risk Estimates

A summary of the estimated occupational post

- application r isks are provided in Table 6.2.2.2

. The short

- and intermediate

- term risk estimates for golf course maint enance activities are greater

than HED’s LOC (MOEs ≥ 100) u sing predicted Day 0 residue values from the TTR study. The

short

- and intermediate

- term risk estimates for ornamentals in greenhou ses and nurseries are greater than HED’s LOC (MOEs ≥ 100) using predicted Day 0 residue values from either the Chrysanthemum or Poinsettia DFR data for all activities.

Table 6.2.2.2. Occupational Post

- application Non

- Cancer Exposure and Risk Estimates for Paclobutrazol

.

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

Short

- and Intermediate

- term

Turf 4 Golf course maintenance, greens only 2,500 0.080 0.004 2,300

Turf 4 M aintenance 3,700 0.080 0.006 1,600

Ornamentals in Nurseries using Chrysanthemum DFR

Data 5 Hand harvesting, Hand pruning, Scouting, Container moving, Hand

Weeding, Transplanting,

Grafting, Propagating,

Pinching, Tying/Training 230 0.73 0.004 2,800

Hand set irrigation 1,900 0.73 0.030 330

Ornamentals in Greenhouse using Chrysanthemum DFR

Data 5 Hand harvesting, Hand pruning, Scouting, Container moving, Hand

Weeding, Transplanting,

Grafting, Propagating,

Pinching, Tying/Training 230 0.73 0.004 2,800

Ornamentals in Nurseries using

Poinsettia DFR Data 6 Hand harvesting, Hand pruning, Scouting, Container moving, Hand

Weeding, Transplanting,

Grafting, Propagating,

Pinching, Tying/Training 230 2.20 0.011 910

Page 32 of 44Table 6.2.2.2. Occupational Post

- application Non

- Cancer Exposure and Risk Estimates for Paclobutrazol

.

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

Short

- and Intermediate

- term

Hand set irrigation 1,900 2.20 0.091 110

Ornamentals in Greenhouse using

Poinsettia DFR Data 6 Hand harvesting, Hand pruning, Scouting, Container moving, Hand

Weeding, Transplanting,

Grafting, Propagating,

Pinching, Tying/Training 230 2.20 0.011 910

1 ( See MRID 45214201, MRID 45310801, MRID 45336601).

2 Daily Dermal Dose = [DFR or TTR (μg/cm 2 ) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption ( 18.7 %)] ÷ BW ( 69 kg).

3 MOE = POD (mg/kg/day) / Daily Dermal Dose. Daily Dermal Dose = [DFR/TTR (μg/cm 2 ) × TC × 0.001 mg/μg × 8 hrs/day × dermal

absorption factor ( 18.7 %)] ÷ BW ( 69 kg).

4 TTR data represents CA which was the test site with the highest residues (MRID 45214201)

. 5 Chrysanthemum DFR data represents use in a greenhouse in Oregon (MRID 45310801)

. 6 Poinsettia DFR data represents use in a shadehouse in Florida (MRID 45336601)

.



### Restricted Entry Interval

Paclobutrazol is classified as Toxicity Category III via the dermal route and or skin irritation potential based on studies submitted in 2012. It is not a skin sensitizer. Short

- and intermediate

term post

- application risk estimates were not a concern on day 0 (12 hours following application) for all post

- applicat ion activities. Under 40 CFR 156.208 (c) (2) (iii), ai’s classified as Acute Toxicity Category III chemicals require a 12

- hr REI. The occupational post

- application assessment, dermal risk estimates do not exceed HED’s level of concern (MOEs >100). Based on the acute dermal toxicity, the 12

- hour REI that appears on the current paclobutrazol labels is supported by the acute toxicity data.

Page 33 of 44

### Appendix A. Summary of Occupational and Residential Non

- cancer Algorithms

Residential Non

- cancer Handler Algorithm s

Handler dermal and/or inhalation exposures are estimated by multiplying the application

method

- specific unit exposure by an estimate of the amount of active ingredient handled in a day, using the following algorithm:

A * AR * UE E =



### where:

E = exposure (mg/day);

UE = unit exposure (mg/lb ai);

AR = application rate (e.g., lb ai/ft 2 

### , lb ai/gal); and

A = area treated or amount handled (e.g., ft 2 

### /day, gal/day).

Dermal and/or inhalation doses are estimated using the following algorithm:



### BW AF * E D =

where:

D = dose rate (mg/kg

- day);

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

BW = body weight (kg).

Dermal and inhalation risks were combined in this assessment, since the toxicological effects for these exposure routes were similar. Dermal and inhalation risks were combined using the following formula:

Total MOE = Point of Departure (mg/kg/day) / Combined dermal + inhalation dose (mg/kg/day)

Residential Non

- cancer Post

- application Algorithms

Dermal exposure:

E = TTRt * CF1 * TC * ET

where :
E = exposure (mg/day);

TTRt = turf transferable residue on day "t" (μg/cm 2 

### );

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

TC = transfer coefficient (cm 2 

### /hr); and

Page 34 of 44

### ET = exposure time (hr/day).

Assumptions:

• A TTR study was used to assess the liquid formulation scenarios ( Turf Enhancer® 2SC Plant Growth Regulator Transferable Turf Residue Study

– MRID No.: 45214201). Data were collected at three sites in the TTR study including New York, Californ ia, and North

Carolina. Data from the California site was used in this assessment as it resulted in the highest predicted Day 0 residues (see Section 4.2.1 and Appendix A for more details)

.

• Transfer coefficients:

o Physical activities on turf: 180,000 cm 2 

### / hr for adults and 49,000 cm 2 

### /hr for children 1 < 2 years old for liquids and 200,000 cm 2 

### /hr for adults and 54,000

cm 2 

### /hr for children for granulars

o Mowing: 5,500 cm 2 

### /hr for adults and 4,500 cm 2 

### /hr for children 11 < 16 years old

o Golfing: 5,300 cm 2 

### /hr for adults, 4,400 cm 2 

### /hr for children 11 < 16 years old, and 2,900 cm 2 

### /hr for children 6 < 11 years old

• Exposure time (hr):

o Physical activities on turf: 1.5 hr for adults and children

o Mowing: 1 hr

o Golfing: 4 hr

Hand

- to

- Mouth:

E = [HR * ( F M 

### * SA H 

### ) * (ET * N_Replen) * (1

- (1

- SE ) (Freq_Replen/N

- Replen) 

### )]

where:

E = exposure (mg/day);

HR = hand residue loading (mg/cm 2 

### );

F M 

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

SA H 

### = typical surface area of one hand (cm 2 

### );

ET = exposure time (hr/day); N_Replen = number of replenishment intervals per hour (intervals/hour);

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

- to

- mouth contacts events per hour (events/hour).

and

2 * SA DE * Faihands HR

H 

### =



### where:

HR = hand residue loading (mg/cm 2 

### );

Fai hands 

### = fraction ai on hands compared to total surface residue from dermal transfer coefficient study (unitless);

DE = dermal exposure (mg); and

SA H 

### = typical surface area of one hand (cm 2 

### ).

Page 35 of 44

### Object

- to

- Mouth:

E = [OR* CF1 * SAM O 

### * (ET * N_Replen) * (1

- (1

- SE O 

### ) (Freq_Replen/N_Replen) 

### )]

where:

E = exposure (mg/day);

OR = chemical residue loading on the object on day “t” (ug/cm 2 

### );

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

SAM O 

### = area of the object surface that is mouthed (cm 2 

### /event);

ET = exposure time (hr/day); N_Replen = number of replenishment intervals per hour (intervals/hour);

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

- to

- mouth contact events per hour (events/hour).

and

OR = AR * F O 

### * CF2 * CF3

where:

OR = chemical residue loading on the object (μg/cm 2 

### );

AR = application rate (lbs ai/ft 2 

### or lb ai/acre);

F O 

### = fraction of residue available on the object (unitl ess);

CF2 = weight unit conversion factor (4.54 x 10 8 

### μg/lb); and

CF3 = area unit conversion factor (1.08 x 10

- 3 

### ft 2 

### /cm 2 

### or 2.47 x 10

- 8



### acre/cm 2 

### ). Soil Ingestion:

E = SRt * SIgR * CF1

where:

E = exposure (mg/day);

SRt = soil residue on day "t" (μg/g); SIgR = ingestion rate of soil (mg/day); and

CF1 = weight unit conversion factor (1 x 10

- 6 

### g/μg).

and

SRt = AR * FS * (1

- F D 

### ) t 

### * CF2 * CF3 * CF4

where:

SRt = soil residue on day "t" (μg/g);

AR = application rate (lbs ai/ft 2 

### or lb ai/acre);

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

F D 

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

t = post

- application day on which exposure is being assessed;

Page 36 of 44

### CF2 = weight unit conversion factor (4.54 x 10 8 

### μg/lb);

CF3 = area unit conversion factor (1.08 x 10

- 3 

### ft 2 

### /cm 2 

### or 2.47 x 10

- 8 

### acre/cm 2 

### ); and

CF4 = soil volume to weight unit conversion factor (0.67 cm 3 

### /g soil).

Mowing:

E = TTRt * CF1 * TC * ET

where :
E = exposure (mg/day);

TTRt = turf transferable residue on day "t " (μg/cm 2 

### );

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

TC = transfer coefficient (cm 2 

### /hr); and

ET = exposure time (hr/day).

and

TTRt = AR * F * (1

- F D 

### ) t 

### * CF2 * CF3

where : TTRt = turf transferable residue on day "t" (μg/cm 2 

### );

AR = application rate (lbs ai/ft 2 

### or lb ai/acre);

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

F D 

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

t = post

- application day on which exposure is being assessed;

CF2 = weight unit conversion factor (4.54 x 10 8 

### μg/lb); and

CF3 = area unit conversion factor (1.08 x 10

- 3 

### ft 2 

### /cm 2 

### or 2.47 x 10

- 8 

### acre/cm 2 

### ).

Golfing:

E = TTRt * CF1 * TC * ET

where :
E = exposure (mg/day);

TTRt = turf transferable residue on day "t" (μg/cm 2 

### );

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

TC = transfer coefficient (cm 2 

### /hr); and

ET = exposure time (hr/day).

and

TTRt = AR * F * (1

- F D 

### ) t 

### * CF2 * CF3

where : TTRt = turf transferable residue on day "t" (μg/cm 2 

### );

AR = application rate (lbs ai/ft 2 

### or lb ai/acre);

Page 37 of 44

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

F D 

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

t = post

- application day on which exposure is being assessed;

CF2 = weight unit conversion factor (4.54 x 10 8 

### μg/lb); and

CF3 = area unit conversion fact or (1.08 x 10

- 3 

### ft 2 

### /cm 2 

### or 2.47 x 10

- 8 

### acre/cm 2 

### ).

For each scenario, absorbed dose (normalized to body weight) was calculated as:

BW AF * E D =



### where :
D = dose (mg/kg

- day);

E = exposure (mg/day);

AF = absorption factor (dermal only; 24.5 %); and

BW = body weight (79.5 kg for adults; 56.8 kg for children 11 < 16 years old, 31.8 kg for children 6 < 11 years old, 11.4 kg for children 1 < 2 years old).

Dermal and incidental oral risk estimates were calculated using the following formula:

MOE = Point of Departure (mg/kg/day) / Dermal or incidental oral dose (mg/kg/day)

where : Dermal NOAEL = 10 mg/kg/day, and Incidental oral NOAEL =18.8 mg/kg/day

Occupational Non

- cancer Handler Algorithms

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

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

where:

E = exposure (mg ai/day),

UE = unit exposure (μg ai/lb ai),

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

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

The daily doses are calculated using the following formula:

ADD= E * AF

BW

where:

Page 38 of 44

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

E = exposure (mg ai/day),

AF = absorpti on factor (dermal and/or inhalation), and

BW = body weight (kg).

Margin of Exposure: Non

- cancer risk estimates for each application handler scenario are calculated using a Margin of Exposure (MOE), which is a ratio of the toxicological endpoint to

the daily dose of concern. The daily dermal and inhalation dose received by occupational handlers are compared to the appropriate POD (i.e., NOAEL) to assess the risk to occupational handlers for each exposure route. All MOE values are calculated using the f ollowing formula:

MOE= POD

ADD

where:

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

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

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

Occupational Non

- cancer Post

- application Algorithms

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:

DFR t 

### = dislodgeable foliage residue on day "t" (μg/cm 2 

### ),

AR = application rate (lb ai/acre),

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

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

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

E=TC * DFR t 

### * ET * 0.001 mg

ug

w here:

E = exposure (mg ai/day),

TC = transfer coefficient (cm 2 

### /hr),

DFR t 

### = dislodgeable foliar residue on day “t” (μg/cm 2 

### ), and

ET = exposure time (hours/day).

Page 39 of 44

### The daily doses are calculated using the following formula:

ADD= E * AF

BW

where:

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

E = exposure (mg ai/day),

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

BW = body weight (kg).

Margin of Exposure: Non

- cancer risk estimates for each scenario are calculated usi ng 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 occu pational post

- application workers. All MOE values are calculated using the following formula:

MOE= POD

ADD

where:

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

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

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

Page 40 of 44

### Appendix B. Paclobutrazol DFR and TTR Study Results

Summary of the TTR Study: Determination of Transferable Residues of Paclobutrazol

Turf Treated with Turf Enhancer 2SC Plant Growth Regulator (MRID 45214201)

The study was designed to determine the total tran s ferable residues (TTR) of paclobutrazol dislodged from turf treated with Turf Enhancer 2SC Plant Growth Regulator, a liquid soluble concentrate formulation containing 22.3 % paclobutrazol as the active ingredient. The test site consisted of three fields located in Madera, California, North Rose, New York, and Creedmoor, North Carolina. Each test site consisted of one untreated control plot (containing 50 subplots)

and one t reated plot (containing 60 subplots). The first application was made at an application rate of 0.5 lb ai/A and the remaining applications were made at 0.75 lb ai/A. Applications were made in California (60

- gallon tank pressure sprayer was used) and New Y ork (30

- gallon cone shaped tank was used) with a commercial tractor

- mounted boom and in North Carolina with a

commercial tractor

- mounted sprayer equipped with a 5

- foot boom. The Modified California Roller technique was used to evaluate the amount of trans ferable residues from turf grass.

First

- order dissipation kinetics were assumed to generate dissipation curves for paclobutrazol at all three test sites. The individual residue data was collected after the last application through the first day when all triplicate TTR levels were less than the level of quantitation (LOQ). For values that were less than the LOQ, a value was used that is one

- half of the LOQ. A linear regression analysis was conducted using the natural logarithm of the individual TTR value s from

cloth dosimeters.

For the California test site, the average paclobutrazol TTR value was 0.0821 ug/cm 2 

### following the third application. The residues dropped below the level of detection fourteen days after

tre atment, third application

. For the Ne w York test site, the average paclobutrazol TTR value was 0.0212 ug/cm 2 

### following the third application. The residues dropped below the level of detection eight days after treatment three. For the North Carolina test site, the average paclobutrazol TTR v alue was 0.156 ug/cm 2 

### following the fourth application. The residues dropped below the level of detection twenty

- two days after treatment four.

The overall average low and high level field fortification recoveries for California were > 90%. The overall average low and high level field fortification recoveries for New York and North Carolina were both <90%. The raw field residue samples were corrected using the corresponding average low or high fortification level recovery for each test site when the recoveries were <90%. For New York, the field residue samples that had the average low level field fortification were corrected for an 83.7% low level average recovery. All of the field samples from the North Carolina test site were correc ted for either the average low level recovery of 81.5% or the average high level recovery of 83.5%.

Based on the results, the half

- life was determined to be 1.77 days (R 2 

### =0.916) for California, 1.50 days (R 2 

### =0.983) for New York and 2.56 days (R 2 

### =0.815) for North Carolina.

The results of the study are acceptable for risk assessment purposes.

Page 41 of 44Table B 1 . Summary of TTR Values and Regression Analysis Results for Turf Enhancer 2SC Plant Growth Regulator Transferable Turf Residue Study (MRID# 45214201).

Inp ut/Parameter New York California North Carolina

Application Rate (lb ai/A) 0.51 (1st application)

0.76 (2nd application)

0.77 (3rd application) 0.51 (1st application)

0.76 (2nd application)

0.77 (3rd application) 0.51 (1st application)

0.75 (2nd application)

0.76 (3rd application)

0.75 (4th application)

Spray Volume (GPA) † 44.0 (1 st application)

44.4 (2 nd application)

44.9 (3 rd application) 44.4 (all applications) 44.0 (1 st , 2 nd , & 3 rd application) 43.6 (4 th application)

Measured Average Day 0 Residue (μg/cm 2 ) 0.212 (1st application) 0.0821 (1st application) 0.0373 (1st application)

Predicted Day 0 Residue (μg/cm 2 ) ‡ 0.018 0.077 0.050

Slope

- 0.4616

- 0.39084

- 0.2703

Half

- life (days) 1.50 1.77 2.56

R 2 0.983 0.916 0.815

Page 42 of 44

### Summary of the DFR Study for Treated Chrysanthemums with Bonzi Ornamental Growth Regulator (MRID# 45310801)

The study review was designed to determine the dissipation of dislodgeable foliar residues (DFR) of paclobutrazol from chrysanthemums treated with BONZI Ornamental Growth Regulator, a liquid formulation containing 0.4% paclobutrazol as the active ingredient (ai). The

tes t site consisted of commercial greenhouses located in Aurora, Oregon. The field trial consisted of one treated plot and one untreated plot that were located in separate greenhouses. A single application was made to chrysanthemums by a hand

- held boom powe red by CO 2 

### . The application was made at an application rate of 0.56 lb ai/A. Leaf discs were collected using a Birkestrand 1.784 cm (0.702 inch) diameter leaf punch.

The DFR samples were collected prior to and immediately after the application, and on d ays 1, 2, 4, 7, 10, 14, 21, 28, and 35 after the application. The average total paclobutrazol DFR on chrysanthemums was 0.755 ug/cm 2 

### twenty

- four hours after the application. By day thirty

- five, the average total paclobutrazol residues declined to 0.202 u g/cm 2 

### . The DFR values did not drop below the limit of quantitation (0.005 ug/cm 2 

### ) during the timeframe of the study.

The DFR values were not corrected because the average low level field fortification recovery was >90%. The midpoint was used between the two fortification concentrations (1.25 ug/cm 2 

### ) as the break point and all of the DFR values were below the midpoint.

Based on the results, the half

- life was determined to be 22.7 days (R 2 

### =0.774). The study was found to be acceptable for use in exposure and risk assessments.

Table B 2

. Summary of DFR Values and Regression Analysis Results for Treated Chrysanthemums with Bonzi (MRID# 45310801).

Input/Parameter Oregon

Application Rate (lb ai/A) 0.56 lb ai/A bench space

Spray Volume (GPA) † 2.87 qt/100 sq ft of bench space (1 st application)

Measured Average Day 0 Residue (μg/cm 2 ) 0.467 (1st application) 0.755(2 nd application) 0.623(3 rd application) Predicted Day 0 Residue (μg/cm 2 ) ‡ 0.684 Slope

- 0.03053

Half

- life (days) 22.7

R 2 0.774

Page 43 of 44

### Summary of the DFR Study for Treated Poinsettas with Bonzi Ornamental Growth Regulator (MRID# 45336601)

The study was designed to determine the dissipation o f dislodgeable foliar residues of paclobutrazol applied to poinsettia s with Bonzi Ornamental Growt h R egulator, a liquid formulation containing 0.4 % paclobutrazol as the active ingredient (ai). Three applications were made to poinsettias at 7

- day intervals in a commercial shadehouse in Stuart, Florida. The three applications were made at a rate of 0. 13 lb ai/Acre with a backpack sprayer with a hand

- held boom powered by CO 2 

### . The field trial consisted of one treated plot and one untreated plot. Leaf discs were collected using a Birkestrand 2.54 cm (1 inch) diameter leaf punch.

The DFR samples were co llected prior to and following each application, and on days 1, 2, 4, 7, 10, 14, 21, 28, and 35 following the last application. The average total paclobutrazol DFR value on poinsettias was 0.439 ug/cm 2 

### after the third (final) application. By thirty

- five days after the last application, the total paclobutrazol residue declined to <LOQ (0.005 ug/cm 2 

### ).

The DFR values were corrected using the average percent recovery of the field fortification samples (88%). The midpoint between the two fortification concen trations (1.25 ug/cm 2 

### ) was used as the break point.

The DFR residue values were not corrected that were below the LOQ (0.005 ug/cm 2 

### ). For residue values that were less than the level of quantification (LOQ) (0.005 ug/cm 2 

### ), 1⁄2 LOQ was

used in the calcula tions.

Based on the results, the half

- life was determined to be 4.55 days (R2=0.911).

The study was found to be acceptable for use in exposure and risk assessments.

Table B 3 . Summary of DFR Values and Regression Analysis Results for Treated Poinsettias with Bonzi (MRID# 45336601).

Input/Parameter Florida

Application Rate (lb ai/A) 0.13 (all application s )

Spray Volume (GPA) † 2.9 qt/100 sq ft of bench space (1 st application ) 3.0 qt/100 sq ft of bench space (2 nd application) 3.0 qt/100 sq ft of bench space (3 rd application)

Measured Average Day 0 Residue (μg/cm 2 ) 0.292 (1st application) 0.326(2 nd application) 0.439 (3 rd application) Predicted Day 0 Residue (μg/cm 2 ) ‡ 0.471 Slope

- 0. 1522

Half

- life (days) 4.55

R 2 0. 914

Page 44 of 44