## Date:

S ubj ec t: UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON

, 

## D

. C. 20460

15-SEP-2015 OFFICE OF CHEMICAL SAFETY

A ND POLLUTION PREVENTION



## Dimethoate. Occupational and Residential Exposure and Risk Assessment for

Re gistration Re view

PC Code: 03500 I DP Barcode: 0418589



### D ecis i o n Nos.: 484715 

### R eg i st r atio n Nos.: N I A



### Petition No. : N I A 

### Regulatory Act ion : R egistration Review

Risk Assessmen t T ype: Single C hemical Case No.: 0088

TXR No.: NA 

### CAS No.: 60-51-5



### MRJD No.: NA 

### 40 CFR: §180.204



## From: Kelly Lowe,

# Environmen~tal**Scienti~ ~j** **~** Jennifer Tyler

, Chemist (/

## · Ri sk Assessment Branch (RABI

/ 

# L

He a lth Effects Di vis ion (HED; 7509P) // 

# ;f 

# L, 

# tr;

Through: Thurston Morton, Acti n g Branch Chief (

# p~~ HED (7509P)



## To:

Introduction and

Margarita Collantes

, Review r

# '77**J~ r:&..~.** **~{11- ({.z.­**  Nancy Keller

, R eviewe r Exposure Science Advisory Co mmitt ee (Expo I 

## HED

Thomas Moriarty Kelly Ballard

Pesticide Re-evaluation Division ( PRD )

As part of Registrat i on Review, the Pesticide R e-eva lu atio n Divis i on (PRD) of OPP ha s

r eq ue s ted that HED evaluate the hazard and expos ur e dat a and conduct occupational and

residential ex po sure assessments

, as needed

, to est imate the risk to human h ea lth that will result

from the current ly registered use s of p est icide s. This memorandum serves as H E D 's Registration Review assessment of the occupational and residential handler and post-application

expos ure and risk from the curre n tly r eg ist e red u ses of dimethoat e.

Pagt: I of 56

### It 

## is HED policy to use the best available data to assess exposure. Severa l so urce s of ge n e ri c
data were used in this assessment as surrogate data in the absence of chemical-spec i fic data,

in cluding P est icide Handler s Exposure Dat abase Version 1.1 (PHED I. I); the Agricultura l

Handler Exposu r e Task Force ( AHETF) database ; the Outdoor Re s idential Exposure Task Force
(ORETF) database ; and the Agricu ltur al Reentry Task Forc e (ART F ) database. Some of these

data are proprietary

, and subject to th e data prot ectio n prov i sions of the Federal In secticide

, F un g icide

, a nd Rodenticide Ac t (FlFRA)

.

Note: 

## This memorandum was reviewed by th e Exposure Sc i ence Adv i so r y Comm i ttee (ExpoSAC) on 10-09- 20 14.

Pa ge 2 of56Page 3 of 56 

## Ta ble of Contents

1.0 Executive Summary

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

2.0 Risk Assessment Conclusions and Recommendations

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

2.1 Summary of Risk Estimates

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

2.2 Label Recommendations

................................ ................................ ................................ .. 8

2.3 Data Deficiencies and Requirements

................................ ................................ ............... 8

3.0 Hazard Characterization

................................ ................................ ................................ ....... 8

4. 0 Exposure and Use Profile

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

5.0 Residential Exposure and Risk Estimates

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

6.0 Non

- Occupational Spray Drift Exposure and Risk Estimates

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

7.0 Non

- Occupational Bystander Post

- Application Inhalation Exposure and Risk Estimates 15

8.0 Occupational Exposure and Risk Estimates

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

8.1 Occupational Handler Exposure/Risk Estimates

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

8.2 Occupational Post

- application Exposure/Risk Estimates

................................ .............. 24

8.2.1 Occupational Post

- application Inhalation Exposure/Risk Estimates

...................... 24

8.2.2 Occupational Post

- application Dermal Exposure/Risk Estimates

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

- cancer Algorithms

..................... 39 Appendix B. Summary of Available DFR Data for Dimethoate

................................ ................. 42 Appendix C. Use Summary for Dimethoate

................................ ................................ ................ 46 Appendix D. Spray Drift Calculations (see excel files)

................................ ............................... 56Page 4 of 56



## 1.0 Executive Summary

Dimetho ate is a general use systemic, organophosphate (OP) insecticide/acaricide that is used to

control a w ide variety of insect pests. The mode of action for dimethoate toxicity inv olves inhibition of the enzyme acetylcholinesterase ( AChE ) via phosphorylation of the serine residue at the active site of the enzyme

. The exposure/ risk assessment for dimethoat e also takes into consideration the toxicity and potential exposure to its major metabolite, omethoate, because omethoate plays a role in the toxicity of dimethoate , and is also f ound in residue studies

. D imethoate must be metabolized (activated) to omethoate , which is the active AChE inhibiting moiety. Omethoate is registered as an active ingredient (ai) internationally, but not in the United

States. This document assesses expo sures and risk estimates from the registered uses of

dimethoate ( which include a gricultural crops, Christmas tree farms

, trees grown for pulp, and

ornamental s in outdoor nurseries ) required during Registration Review

. There are current ly no registered residential uses ; however

, there is the potential for non

- occupational exposure as a

result of spray drift

.

U se Profile

There are numerous end

- use product labels registered with dimethoate as the ai

. These include liquids and water soluble package (WSP) formulations. Most of the registered products are applied either via aerial, chemigation, airblast, groundboom

, or with handheld equipment. For most use sites/crops

, t he maximum application rate is 2 lb ai/A; but for ornamentals in outdoor nurseries, the maximum application rate is 4.15 lb ai/A for airblast applications specifically

.

Exposure Profile Occupational handler s are anticipated to be exposed to dimethoate only (i.e., not its metabolite, omethoate) . D ue to the degradation of dimethoate once applied, post

- application workers may be exposed to residues of both dimethoate and omethoate. In terms of personal protective equipment (PPE), m ost of the dimethoate registered labels require handlers to wear a si ngle layer of clothing (long sleeved shirt and long pants), shoes plus socks, protective eyewear (either goggles or face shield ) , chemical

- resistant gloves, a NIOSH

- approved dust/mist filtering respirator with MSHA/NIOSH approval number prefix TC

- 21C or a NIOSH

- approved respirator with any N, R, P, or HE filter, and a chemical

- resistant apron when mixing, loading, cleaning up spills, or equipment. Depending on the crop and geographical area of application (i.e., arid

versus non

- arid) , the registered labels for dimethoate recommend a range of restricted entry intervals (REIs) from 48 hours to 24 days. A s noted above, t here are currently no registered

residential uses ; however, there is the potential for non

- occupational exposure (dermal and incidental oral) as a result of spray drift

.

Hazard Profile and Dose Response Since this assessment considers exposure and risk from both dimethoate and its metabolite

, omethoate, toxicity and hazard information related to both are included in the hazard

characterizat ion. All of the toxicity studies currently available for both dimethoate and omethoate have been utilized in picking endpoints and points of departure (PODs) for the various routes of exposure.Page 5 of 56



## Dimethoate is classified as having low acute toxicity via the oral , dermal, and inhalation routes ( Toxicity Category III or IV). It was found to be a moderate eye irritant, but not a dermal irritant

or dermal sensitizer. Omethoate is classified as acutely toxic via the oral, dermal, and inhalation routes (C ategory I or II).

Dimethoate is an OP with a neurotoxic adverse outcome pathway (AOP); neurotoxicity is the most sensitive effect in all species, routes, and lifestages

, and is being used in deriving P O Ds.

D imethoate must be metabolized (activated) to omethoate, which is the active AChE inhibiting moiety

. Dimethoate and omethoate have high quality dose response data across multiple lifestages, durations, and routes for both red blood cell (RBC) and brain ACh E inhibition. Many of these studies have been evaluated using benchmark dose (BMD) modeling techniques. BMD estimates are similar across age, sex, and method of administration (gavage, feeding, drinking water) for dimethoate and omethoate (Appendix 9 of USEPA 2004 1 

## ). High quality studies for

the dermal and inhalation routes with dimethoate and omethoate, respectively, allow for route specific evaluation.

The steady

- state incidental oral POD (BMDL 10 

## = 0.22 mg/kg) was selected from the OP

Cumulative Ri sk Assessment ( CRA ) (USEPA, 2002 and 2006) , and is based on a dimethoate combined chronic oral toxicity/carcinogenicity study . The BMD 10 

## of 0.25 mg/kg was based on

brain AChE inhibition. The steady

- state dermal POD was selected from a dimethoate 28

- day

d ermal toxicity study in rats based on brain AChE inhibition in female rats (BMDL 10 

## = 20.2 mg/kg/day; BMD 10 

## = 28.5 mg/kg/day). The steady

- state inhalation POD was selected from a n omethoate 28

- day inhalation toxicity study based on brain AChE inhibition in male rats (B MC L 10 

## = 0.38 mg/m 3 

## /day or 0.00038 mg/L/day; BM C 10 

## = 0.51 μg/L/day or 0.00051 mg/L/day).

Omethoate has been found to be a more potent AChE inhibitor than dimethoate. Because of this,

and because the PODs for risk assessment are based on both dimethoate and omethoate toxicity studies, the potential exposure profiles were examined to determine if adjustment factors were necessary to account for the increased potency of omethoate. For occupational handlers, exposure is anticipated to be to the parent, dimethoate, only . T he dermal route of exposure is assessed using a dim ethoate

- specific toxicity study; therefore, no toxicity adjustment factors (TAFs) were used in the dose calculations . The inhalation route of exposure is assessed using an

omethoate

- specific toxicity study since a dimethoate

- specific inhalation toxicity study is not

available . No TAFs were used in the dose calculations , but it should be noted that the risk estimates presented are representa tive of exposure to the more toxic metabolite , omethoate, and, therefore, are a conservative estimate of potential exposure to dimethoate. For occupational

post

- application workers, exposure is anticipated to be to both dimethoate and omethoate. Since

th e dermal route of exposure is assessed using a dimethoate

- specific toxicity study, the omethoate residues have been adjusted by a TAF to account for the increased potency of

omethoate.

Resulting occupational dermal and inhalation risk estimates were combined since the same effects were observed for both routes of exposure (brain AChE inhibition ). Residential post

-

1 Appendix 9: BMD Analysis of Brain Cholinesterase Inhibition Data. November 2, 2004. SAP Meeting “ Dimethoate: Issues Related to the Hazard and Dose Response Assessment. ” ttp://www.epa.gov/scipoly/sap/meetings/2004/november/appendix9.pdfPage 6 of 56



## application dermal and incidental oral risk estimates were also combined since the same effects were observed for both routes of exposure ( brain AChE inhibition). For residential incidental oral and dermal scenarios, a total uncertainty factor of 1000X was applied ( 10 X for interspecies extrapolation, 10X for intraspecies variation, and a 10X Food Quality Protection Act ( FQPA ) safety factor ( SF) due to uncertainty in the human dose

- response relationship for neurodevelopmental effects 2 

## ). For occupational dermal and inhalation scenarios, a total uncertainty factor of 1000X was applied ( 10 X for interspecies extrapolation, 10X for intraspecies variation, and a 10X database uncertainty factor due to uncertainty in the human dose

- response relationship for neurodevelopmental effects ).

Dimethoate is classified as a Group C carcinogen

- possible human carcinogen ( Memo; K. Dearfield; 29

- AUG

- 1991). On June 25, 1992, the FIFRA SAP concurred with the Agency's classification of dimethoate as a Group C carcinogen. Quantitative risk assessment for dimethoate using the RfD approach will adequately acco unt for all chronic toxic effects, including carcinogenicity.

Residential Exposure and Risk

There are currently no registered residential uses of dimethoate.

Non

- Occupational Spray Drift Exposure and Risk A quantitative non

- occupational spray drift assessment was conducted for the registered uses of

dimethoate. The assessment takes into consideration both dimethoate residues and residues of the major metabolite, omethoate. Adult dermal and children’s (1 to < 2 year old) dermal and

incidental oral r isk estimates from indirect exposure related to spray drift are of concern (MOEs

≤ 1000) at a range of distances from the edge of the field depending on the spray

- drift scenario (e.g., 0 to >300 feet). Results indicate that the major spray

- drift risk concern s are from aerial applications.

Occupational Exposure and Risk Occupational handler dermal and inhalation exposure and risk estimates were calculated for the registered uses of dimethoate. The occupational handler exposure and risk estimates in dicate

that the dermal and inhalation combined MOEs are of concern to HED (i.e., MOE s ≤ 100 0 ) for most scenarios assuming the use of label

- required PPE. As was noted above, the inhalation risk estimates are considered to be a conservative estimate of expo sure to dimethoate residues considering the inhalation POD was selected from an omethoate toxicity study. Only five scenarios (out of 40) reach an MOE above the LOC of 1000 at some level of PPE (above what is currently required on the labels) or with engi neering controls.

O ccupational post

- application dermal exposure and risk estimates were assessed for all registered uses of dimethoate using submitted chemical

- specific dislodgeable foliar residue (DFR) data. The post

- application assessment takes into co nsideration both dimethoate residues and residues of the major metabolite , omethoate ; both of which were measured in the available

DFR studies

. Based on the current exposure assessment, post

- application ris k estimate s remain a

concern in some situations for more than 30 days after application (i.e., MOEs < 100 0 ). Current product

- label REIs range from 48 hours to 24 days depending on the crop and geographic

2 For more details, see Section 4.4 in the human health risk assessment: Me mo, M. Perron et al , 15

- SEP

- 2015, D416010.Page 7 of 56



## location (i.e., arid versus non

- arid). Even though REIs of 12 and 24 hours may be long enough

for MOEs to reach the LOC of 100 0 for some crops/activities, HED recommends a minimum REI of 48 hours (72 hours in arid regions ) to be protective of potential for exposure to omethoate which is known to form after application. These REIs are in line with the 40 CFR 156.208 (c) (2 ) assignments for active ingredients that are classified as Toxicity Category I for acute dermal, eye irritation

, and primary skin irritation

.

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

- cancer occupational post

- application inhalation exposure assessment was not performed for dimethoate at this time. If new policies or procedures are put into place, the Agency may revisit the nee d for a quantitative occupational

post

- application inhalation exposure assessment for dimethoate

.

Human Studies Review This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pesticide or othe r chemical. These data, which include studies from the PHED 1.1, ORETF, the AHETF database, and the ARTF database are (1) subject to ethics review pursuant to 40 CFR 26, (2) have received that review, and (3) are compliant with applicable ethics requireme nts. 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 3



## .

2.0 Risk Assessment Conclusions and Recommenda tions

2.1 Summary of Risk Estimates

 The occupational handler exposure and risk estimates indicate that the steady

- state
dermal and inhalation combined MOEs are of concern for many scenarios with the use of

label

- recommended PPE

, and continue to be a concern even with highest level of PPE and/or mitigation (i.e., engineering controls) available

.

 Occupational post

- application dermal exposure and risk estimates were assessed for all

uses and based on the current exposure assessment, REIs of 12 hours to more than 30 days are necessary to reach acceptable MOEs (i.e., MOEs ≥ 100 0 ). Even though REIs of

12 and 24 hours may be long enough for MOEs to reach the LOC of 1000 for some crops/activities, HED recommends a minimum REI of 48 hours (72 hours in arid regions) to be protective of potential for exposure to omethoate which is known to form after application. Current product label REIs range from 48 hours to 24 days depending on the crop and loca tion

.

 The spray drift assessment indicates that risk management options such as buffers may be necessary for certain use site/application scenarios

, and/or label modifica tions designed

to reduce risks may be necessary to reduce drift such as nozzles in t he drift reduction technology program

.

3 

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

- exposure

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

- app

- exposure

- data.htmlPage 8 of 56



## 2.2 Label Recommendations

No label recommendations have been identified. A summary of the risk estimates has been provided

, and shows that there are risk estimate s of concern for registered uses of dimethoate

based on the label

- required personal protective equipment and restricted entry intervals (REIs)

.

2.3 Data Deficiencies and Requirements

In accordance with 40CFR158, TTR data are required for all occupational (e.g., sod farms, golf courses, parks, and re creational areas) or residential turf uses that could result in post

- application exposure to turf

, and DFR data are required for all occupational (e.g., crop, nursery, greenhouse use sites) or residential (e.g., ornamental and vegetable gardens, pick your own farms, retail tree farms) uses that could result in post

- application exposure to foliage. In the absence of chemical

specific TTR and/or DFR data, EPA uses default values. In the case of dimethoate, there are no registered turf uses; therefore, TTR d ata are not required at this time. Acceptable DFR studies have been submitted and incorporated into the current Registration Review assessment.

3 .0 Hazard Characterization

Th is assessment considers exposure and risk from both dimethoate and its metabol ite

, omethoate; therefore, toxicity and hazard information related to both are included in the hazard

characterization. The database of toxicology studies for dimethoate is considered complete

. Although never registered as an ai in the U.S., omethoate has in the past been registered in other countries and, as a result, there is an extensive toxicity database for omethoate. All of the toxicity studies currently available for both dimethoate and omethoate have been utilized in pic king endpoints and PODs for the various routes of exposure.

Dimethoate is classified as having low acute toxicity via the oral, dermal, and inhalation routes ( Toxicity Category III or IV). It was found to be a moderate eye irritant, but not a derma l irritant

or dermal sensitizer. Omethoate is classified as acutely toxic via the oral, dermal, and inhalation routes (Category I or II). Table s 3.1 and 3.2 present a summary of the acute toxicity information

for dimethoate and omethoate, respectively

.

Table 3.1. Acute Toxicity Profile

– Dimethoate.

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

870.1100 Acute oral (rat) 48890603 LD50 = 550 mg/kg (F) III

870.1200 Acute dermal (rabbit) 48890604 LD50 > 5000 mg/kg IV

870.1300 Acute inhalation (rat) 48890605 LC50 > 2.1 mg/L IV

870.2400 Acute eye irritation (rabbit) 48890606 Moderate irritant II

870.2500 Acute dermal irritation (rabbit) 48890607 Not a dermal irritant IV

870.2600 Skin sensitization (guinea pig) 48890608 Not a sensitizer N/A

Table 3.2. Acute Toxicity Profile

– Omethoate.

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

870.1100 Acute oral (rat) 46099809 LD50= 22/28 mg/kg (M/F) I

870.1200 Acute dermal (rat) 46099810 LD50= 215 mg/kg I

870.1300 Acute inhalation (rat) 46099813 LC50= 0.28 mg/kg IIPage 9 of 56



## Dimethoate is an OP with a neurotoxic AOP ; neurotoxicity is the most sensitive effect in all species, routes, and lifestages

, and is being used in deriving P O Ds. D imethoate must be metabolized (activat ed) to omethoate, which is the active AChE inhibiting moiety

. Dimethoate

and omethoate have high quality dose response data across multiple lifestages, durations, and

routes for both RBC and brain AChE inhibition. Many of these studies have been evaluat ed using BMD modeling techniques. BMD estimates are similar across age, sex, and method of administration (gavage, feeding, drinking water) for dimethoate and omethoate (Appendix 9 of

USEP A 2004). High quality studies for the dermal and inhalation routes with dimethoate and omethoate, respectively, allow for route specific evaluation.

OPs exhibit a phenomenon known as steady state AChE inhibition. After repeated exposure at

the same dose, the degree of inhibition comes into equilibrium with the production of new, uninhibited enzyme. At this point, the amount of AChE inhibition at a given dose remains

consistent across duration. In general, OPs reach steady state within 2

- 3 w ee ks

, but this can vary among OPs. In the case of dimethoate, the pattern of steady state is reached at or near 11 days of

exposure. In addition to the consistency across durations, the data across multipl e repeat dosing

studies in rats are similar. For t he purposes of the occupational and residenti al risk assessment, only the steady

- state duration is relevant to the exposure scenarios.

Consistent with risk assessments for other AChE

- inhibiting compounds, OPP has used a benchmark response (BMR) level of 10%

, and has thus calculated BMD 10 

## and BMDL 10 

## values.

The BMD 10 

## is the estimated dose where AChE is inhibited by 10% compared to background.

The BMDL 10 

## is the lower confidence bound on the BMD 10 

## . As a matter of science policy, the agency uses the BMDL, not the BMD, for use as the POD (USEPA, 2012 4 

## ).

The steady

- state incidental oral POD (BMDL 10 

## = 0.22 mg/kg) was selected from the OP CRA (USEPA, 2002 and 2006) , and is based on a dimethoate combined chronic oral toxicity/carcinogenicity study . The BMD 10 

## of 0.25 mg/kg was based on brain AChE inhibition.

The steady

- state dermal POD was selected from a dimethoate 28

- day dermal toxicity study in rats based on brain AChE inhibition in female rats (BMDL 10 

## = 20.2 mg/kg/day; BMD 10 

## = 28.5 mg/kg/day).

The st eady

- state inhalation POD was selected from a n omethoate 28

- day inhalation toxicity study based on brain AChE inhibition in male rats (B MC L 10 

## = 0.38 mg/m 3 

## /day or 0.00038 mg/L/day; BM C 10 

## = 0.51 μg/L/day or 0.00051 mg/L/day). Due to the lack of characterization of particle sizes in the study, the mass median aerodynamic diameter (MMAD) and geometric standard deviation could not be determined. As a result, human equivalent concentrations could not be estimated for the systemic effects (AChE inhib ition) from inhalation exposure. For occupational scenarios, duration adjustments were made to extrapolate exposure in the animal study (6 hours/day; 5 days/week) to a typical occupational exposure (8 hours/day; 5 days/week). The resulting duration adjus ted value for occupational exposures is 0.285 mg/m 3 

## . For the purpose of estimating occupational inhalation risks from different occupational activities,

4 

### US EPA (U.S. Environ mental Protection Agency). 2012 . Benchmark Dose Technical

G uidance. http://www.epa.gov/raf/publications/pdfs/benchmark_dose_guidance.pdfPage 10 of 56



## inhalation doses corresponding to the breathing rates for each activity (8.3, 16.7, or 29 L/min)

were calculated using this duration adjusted value.

For residential incidental oral and dermal scenarios, a total uncertainty factor of 1000X was applied ( 10 X for interspecies extrapolation, 10X for intraspecies variation, and a 10X FQPA safety factor due to uncertainty in the human dose

- response relationship for neurodevelopmental

effects 5 

## ). For occupational dermal and inhalation scenarios, a total uncertainty factor of 1000X was applied ( 10 X for interspecies extrapolation, 10X for intraspecies variation, an d a 10X database uncertainty factor due to uncertainty in the human dose

- response relationship for neurodevelopmental effects ).

Omethoate has been found to be a more potent AChE inhibitor than dimethoate. Because of this,

and because the PODs for risk as sessment are based on both dimethoate and omethoate toxicity studies, the potential exposure profiles were examined to determine if TAFs were necessary to account for the increased potency of omethoate . For occupational handlers, exposure is anticipated to be to the parent, dimethoate, only. The dermal route of exposure is assessed using

a dimethoate

- specific toxicity study, therefore, no adjustments were made to the doses

calculated. The inhalation route of exposure is assessed using an omethoate

- specific toxicity study since a dimethoate

- specific inhalation toxicity study is not available . No adjustments to the doses were made, but it should be noted that the risk estimates presented are representa tive of exposure to the more toxic metabolite , omethoate, and, therefore, are a conservative estimate of potential exposure to dimethoate. For occupational post

- application workers, exposure is anticipated to be to both dimethoate and omethoate. Residues of both have been measured in

submitted DFR studies. Since the dermal route of exposure is assessed using a dimethoate

specific toxicity study, the omethoate residues have been adjusted by a TAF to account for the increased potency of omethoate. TAFs we re estimated previously using BMD modeling to evaluate relative potency for dimethoate and omethoate ( A. Lowit; 11

- APR

- 2005; TXR# 0052940) . T he originally calculated steady

- state TAF of 3 for omethoate (A. Lowit; 24

- APR

2002) was verified with additional subchronic and chronic studies. For this risk assessment, no changes were made, and this value has been used in the post

- application exposure calculations for Registration Review.

Dimethoate is classified as a Group C carcinogen

- possible human carcin ogen ( Memo; K. Dearfield; 29

- AUG

- 1991). On June 25, 1992, the FIFRA SAP concurred with the Agency's classification of dimethoate as a Group C carcinogen. Quantification of risk using a non

- linear approach will adequately account for all chronic toxicity, including carcinogenicity that could result from exposure to dimethoate.

Table 3.3

. Summary of Toxicological Doses and Endpoints for Dimethoate for Use in Non

- Occupational and Occupational Human Health Risk Assessments Exposure/

Scenario Point of Departure

(POD) Uncertainty

Factors a Level of Concern

(LOC) Study and Toxicological

Effects

Incidental Oral Steady State (21 days and longer) BMDL 10 =

0.22 mg/kg/day UF A = 10x

UF H = 10x FQPA SF = 1 0 x Residential LOC

for MOE = 100 0 Dimethoate Combined chronic oral

toxicity/carcinogenicity study (OP CRA 2002, 2006; MRID 00164177)

BMD 10 = 0.25 mg/kg/day

5 For more details, see Section 4.4 in the human health risk assessment: Memo, M. Perron et al , 15

- SEP

- 2015, D416010.Page 11 of 56

Table 3.3

. Summary of Toxicological Doses and Endpoints for Dimethoate for Use in Non

- Occupational and Occupational Human Health Risk Assessments Exposure/

Scenario Point of Departure

(POD) Uncertainty

Factors a Level of Concern

(LOC) Study and Toxicological

Effects

Inhibition of brain AChE in adult rats

Dermal Steady

State (21 days and longer) BMDL 10 =

20.2 mg/kg/day UF A = 10x

UF H = 10x FQPA SF /

UF DB = 10x Occupational /

Residential LOC

for MOE = 100 0 Dimethoate 28

- day rat dermal toxicity

(MRID 44999101)

BMD 10 = 28.5 mg/kg/day

Inhibition of brain AChE in adult rats

Inhalation Steady State (21 days and longer) BMCL 10 =

0.38 mg/m 3 /day b UF A = 10x

UF H = 10x

UF DB = 10x Occupational

LOC for MOE =

100 0 Omethoate 21

- day inhalation rat study

(MRID 46358601)

BMC 10 = 0.51 mg/m3/day

Inhibition of brain AChE in adult rats Cancer (oral, dermal, inhalation) Classification: Group C carcinogen (possible human carcinogen)

a. For residential incidental oral and dermal scenarios, FQPA SF retained for infants, children, youths, and women of childbearing age for all exposure scenarios due to uncertainty in the human dose

- response relationship for neurodevelopmental effects (see Section 4.4 of the human health risk assessment, D416010 ). For occupational dermal and inhalation scenarios, UF DB = database uncertainty factor for uncertainty in the human dose

- response relationship for neurodevelopmental effects (see Section 4.4 of the human health risk assessment, D416010).

b. Occupational inhalation PODs = 0.016, 0.033, and 0.057 mg/kg/day for the b reathing rates of 8.3, 16.7, and 29 L/min, respectively.

Point of departure (POD) = A data point or an estimated point that is derived from observed dose

- response data and used to mark the beginning of extrapolation to determine risk associated with lo wer environmentally relevant human exposures. 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 sensit ivity among members of the human population (intraspecies). MOE = margin of exposure. LOC = level of concern. BMD = benchmark dose. BMDL = lower 95% confidence

interval for benchmark dose.



## Absorption : Since the dermal and inhalation POD s were based on route

- specific toxicity studies

, absorption factor s w ere not necessary to estimate exposure.

Body Weight: For adults, when an endpoint is not sex

- specific (i.e., the endpoints are not based on developmental or fetal effects) a body weight of 80 kg is typically used in risk assessment; however, in this case, a female

- specific body weight of 69 kg was used. While the endpoint of concern, brain AChE inhibition, is not sex

- specific, the female

- specific body weight was used to protect for pregnant women due to uncertainty in the human dose

- response relationship f or neurodevelopmental effects 6



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

4 .0 Exposure and Use Profile

There are numerous end

- use p roduct labels registered with dimethoate as the ai . These include liquid and WSP formulations. The labeled use sites include various agricultural crops, Christmas tree farms and trees grown for pulp, and ornamentals in outdoor nurseries

. Most of the reg istered products are applied either via aerial, chemigation, airblast, groundboom or with handheld

6 For more details, see Section 4.4 in the human health risk assess ment: Memo, M. Perron et al, 15

- SEP

- 2015, D416010.Page 12 of 56



## equipment. For most use sites/crops, the maximum application rate is 2 lb ai/A; but for ornamentals in outdoor nurseries, the maximum application rate is 4. 15 lb ai/A for airblast applications specifically.

Based on the registered use pattern for dimethoate, dermal and inhalation exposures are anticipated for occupational handlers and post

- application workers. Occupational handler s are anticipated to be exposed to the parent, dimethoate, only . Occupational post

- application workers may be exposed to residues of both dimethoate, and its metabolite , omethoate. In terms of personal protective equipment (PPE), most of the dimethoate registered labels require handlers to wear a single layer of clothing (long sleeved shirt and long pants), shoes plus socks, protective eyewear (either goggles or face shield ) , chemical

- resistant gloves, a NIOSH

- approved dust/mist filtering respirator with MSHA/NIOSH approval numb er prefix TC

- 21C or a NIOSH

- approved respirator with any N, R, P, or HE filter, and a chemical

- resistant apron when mixing, loading, cleaning up spills, or equipment. Depending on the crop and geographical area of application (i.e., arid versus non

- arid)

, the registered labels for dimethoate recommend a range of restricted entry intervals (REIs) from 48 hours to 24 days. As noted above, t here are currently no registered residential uses ; however, there is the potential for non

- occupational exposure (derma l and incidental oral) as a result of spray drift

. A summary of registered labels and dimethoate use directions are included in Appendix C

.

5 .0 Residential Exposure and Risk Estimates

All residential and other non

- occupational uses of dimethoate were voluntarily cancelled, effective March 13, 2002 (Federal Register Notice/Vol. 67, No. 84/Wednesday, May 01, 2002/Notices/21669). Currently, dimethoate is registered solely for use on occupational sites.

6.0 Non

- Occupational Spray Drift Exposure and Ris k Estimates

Off

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

target and can lead to exposures to those it may directly contact. They can also deposit on surfaces where contact with residues can eventually lead to indirect exposures ( e.g. , children playing on lawns where residues have deposited next to treated fields). The potential risk

estimates from these residues can be calculated using drift modeling onto 50 feet wide lawns coupled with methods employed for residential risk assessments for turf products.

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

on a premise of compliant applications which, by definition, should not result in direct exposures to individuals because of existing label language and other regulatory requirements intended to prevent them. 7 

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

7 This approach is consistent with the requirements of the EPA’s Worker Protection Standard.Page 13 of 56



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

considered in risk assessment.

In order to evaluate the drift potential and associated risks, an approach based on drift modeling coupled with techniques used to evaluate residential uses of pesticides was utilized. Essentially, a

residential turf assessment based on exposure to deposited residues has been completed to address drift from the agricultural applications of dimethoate. In the spray drift scenario, the deposited residue value was determined based on the amount of spray drift that may occur at varying dist ances from the edge of the treated field using the AgDrift ( v2.1.1) model and the Residential Exposure Assessment Standard Operating Procedures Addenda 1: Consideration of Spray Drift Policy

. Once the deposited residue values were determined, the remainder of the spray drift assessment was based on the algorithms and input values specified in the recently revised (2012) Standard Operating Procedures For Residential Risk Assessment (SOPs)

.

For dimethoate, chemical

- specific TTR data are not available, there fore, the estimated TTR are based on a default assumption from the 2012 Residential SOPs that the transferable residue available for exposure is 1% of the total deposited residue, which is assumed to be equivalent to the maximum application rate. In order to account for the formation the metabolite, omethoate, an assumption was made that 5% of the dimethoate residues would metabolize to omethoate. This assumption is based on a review of available TTR and DFR data for other OPs where both the parent and me tabolite were measured in residue samples. Five percent was found to be the high

- end value for the percent of parent that metabolized during the course of the residue studies.

Once the estimated omethoate residues were calculated (dimethoate residues * 5 %), the resulting values were adjusted further by the TAF value of 3 to account for the increased potency of

omethoate since a dimethoate

- specific dermal toxicity study was used for calculation of the risk

estimates.

A screening approach was developed b ased on the use of the AgDrift model in situations where specific label guidance that defines application parameters is not available. 8 

## AgDrift is appropriate for use only when applications are made by aircraft, airblast orchard sprayers, and groundboom sp rayers. When AgDrift was developed, a series of screening values (i.e., the Tier 1 option) were incorporated into the model and represent each equipment type and use under varied conditions. The screening options specifically recommended in this methodol ogy were selected because they are plausible and represent a reasonable upper bound level of drift for common application methods in agriculture. These screening options are consistent with how spray drift is considered in a number of ecological risk asse ssments and in the process used to develop drinking water concentrations used for risk assessment. In all cases, each scenario is to be evaluated unless it is not plausible based on the anticipated use pattern (e.g., herbicides are not typically applied t o tree canopies) or specific label prohibitions (e.g., aerial applications are not allowed). In many cases, risks are of concern when the screening level estimates for spray drift are used as the basis for the analysis. In order to account for this issue and to provide additional risk management options additional spray drift deposition fractions were also considered. These drift estimates represent plausib le options for pesticide labels.

Combined Risk Estimates from Lawn Deposition Adjacent to Applications

8 http://www.agdrift.com/Page 14 of 56



## The spray drift risk estimates are based on an estimated deposited residue concentration as a result of the screening level agricultural application scenarios

. Dimethoate is registered on

various agricultural crop s, Christmas tree farms and trees grown for pulp, and ornamentals in

outdoor nurseries

. Most of the registered products are applied either via aerial, chemigation, groundboom , airblast or with handheld equipment. For most use sites , the maximum applicati on

rate is 2 lb ai/A; but for ornamentals in outdoor nurseries, the maximum application rate is 4.15 lb ai/A for airblast applications specifically. The recommended drift scenario screening level options are listed below:

 Groundboom applications are base d on the AgDrift option for high boom height and using very fine to fine spray type using the 90 th 

## percentile results.

 Orchard airblast applications are based on the AgDrift option for Sparse (Young/Dormant) tree canopies.

 Aerial applications are based on the use of AgDrift Tier 1 aerial option for a fine to medium spray type and a series of other parameters which will be described in more detail below (e.g., wind vector assumed to be 10 mph in a downwind direction for entire application/drift event).

In addition to the screening level spray drift scenarios described above, additional results are provided which represent viable drift reduction technologies (DRTs) that represent potential risk management options. In particular, different spray qualities h ave been considered as well as the impact of other application conditions (e.g., boom height, use of a helicopter instead of fixed wing aircraft, crop canopy conditions).

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

children ( 1 to <2 years old ) were combined because the toxicity endpoint for each route of exposure is the inhibition of brain cholinesterase (ChE). The total applicable LOC is 100 0

, so MOEs < 100 0 represent risk estimates of concern.

Adult dermal and children’s (1 to < 2 year old) dermal and incidental oral risk estimates related to spray drift result in a range of buffers depending on the spray drift scenario . These are

summarized in Table 6.0.1 (all drift calculations are provided i n Appendix D as excel files)

. Results indicate that the major risk concern is from aerial applications

. Appropriate drift reduction technologies such as changing the spray type/nozzle configuration to coarser spray applications may result in less drift and reduced risk concerns (i.e., higher MOEs) from aerial applications. Similarly, using coarser sprays and lowering boom height for groundboom

sprayers reduces risk concerns.

Table 6.0.1 . Summary of Spray Drift Buffers for Dimethoate.

Crop Category Cr ops Application rate (lb ai/A) Adult Buffer Summary Children 1 < 2 years Buffer Summary (Dermal + Incidental Oral)

Buffers Necessary to reach MOE of

100 0 Buffers Necessary to reach MOE of

100 0

Aerial Groundboom Airblast Aerial Groundboom Airblast

Forestry Cottonwoods grown

for pulp 2 100

- >300 NA NA >300 NA NAPage 15 of 56

Table 6.0.1 . Summary of Spray Drift Buffers for Dimethoate.

Crop Category Cr ops Application rate (lb ai/A) Adult Buffer Summary Children 1 < 2 years Buffer Summary (Dermal + Incidental Oral)

Buffers Necessary to reach MOE of

100 0 Buffers Necessary to reach MOE of

100 0

Aerial Groundboom Airblast Aerial Groundboom Airblast

High Acreage Crops Alfalfa (field and

seed crop), Beans (fresh, snap, lima, dry, not cowpeas), Corn (field and popcorn), Cotton, Grass grown for seed, Potatoes, Safflower, Sorghum, Soybeans,

Wheat 0.5 25

- >300 0

- 25 125

- >300 10

- 150

Typical Acreage Crops Brussels sprouts 1 50

- >300 0

- 50 200

- >300 25

- 250

Asparagus, Broccoli, Cauliflower, Celery, Garbanzo beans, Lentils, Melons, Peas,
Tomatoes,

Watermelon 0.5 10

- >300 0

- 10 125

- >300 10

- 125

Peas, dry; Peas, succulent; Peppers 0.33 0

- 200 0

- 10 75

- >300 10

- 75

Kale, Mustard greens, Turnip 0.25 0

- 150 0

- 10 75

- >300 10

- 75

Peas 0.16 0

- 75 0 50

- >300 0

- 50

Nurseries /

Orchard Ornamentals in

outdoor nurseries 4.15

NA 0

- 100

NA 25

- 250

Citrus

- non

- bearing and nursery stock, Cherries (preharvest and postharvest),

Christmas tree nurseries, Citrus, Pears (including non

bearing and nursery stock) 1 0

- 25 0

- 100

Lupine 0.5 0

- 10 0

- 75

Orchard Pecans 0.33 0

- 10 0

- 50



## 7.0 Non

- Occupational Bystander Post

- Application Inhalation Exposure and Risk

Estimates

Volatilization of pesticides may be a source of post

- application inhalation exposure to individuals nearby pesticide applications. The agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP’s final report on March 2, 2010 ( http://www.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/#!do cketDetail;D=EPA

- HQ

- OPP

- 2014

- 0219). During RegistrationPage 16 of 56



## Review, the Agency will utilize this analysis to determine if data (i.e., flux studies) or further analysis are required for dimethoate.

8 .0 Occupational Exposure and Risk Estimates

8 .1 Occupationa l 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 d epending on the specifics of each task. Job requirements (amount of chemical used in each application), the kinds of equipment used, the target being treated, and the level of protection used by a handler can cause exposure levels to differ in a

manner sp ecific to each application event.

The quantitative exposure/risk assessment developed for occupational handlers is based on the following scenarios which cover all the registered uses of dimethoate :

 Mixing/loading liquids and water soluble packets to support aerial applications,

 Mixing/loading liquids and water soluble packets to support airblast applications,

 Mixing/loading liquids to support chemigation applications,

 Mixing/loading liquids and water soluble packets to support groundboom applications,

 Applying sprays with aircraft,

 Applying sprays with groundboom equipment,

 Applying sprays with airblast equipment,

 Flagging to support aerial spray applications,

 Mixing/loading/applying liquids via backpack,

 Mixing/loading/applying liquids via mechanica lly

- pressurized handgun, and

 Mixing/loading/applying liquids via manually

- pressurized handwand.

Occupational Handler Exposure Data and Assumptions A series of assumptions and exposure factors served as the basis for completing the occupational

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

Application Rate : The application rates used in this assessment are provided in Appendix C

. For similar crop/application method scenarios, the highest application rat e was assessed assuming this would be protective of lower application rates.

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

- 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 t he data protection provisions of FIFRA. The standard values recommended for use in predicting handler exposure that are used in this assessment, known as “unit exposures”, are outlined in the “Occupational Pesticide Handler UnitPage 17 of 56



## Exposure Surrogate Referen ce Table 9 

## ”, 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 10



## .

Area Treated or Amount Handled : The inputs for area treated were based on information in ExpoSAC Policy 9.1. The following summarizes the inputs used for estimating handler

exposures:

 7500 acres for aerial application to forestry crops

,

 1200 acres for aerial application to high acreage crops
,

 350 acres for aerial application to typical acreage crops and orchards

,

 350 acres for chemigation applications

,

 350 acres for flaggers

,

 200 acres for ground application to high acreage crops

,

 80 acres for ground application to typical acreage crops

,

 60 acres for aerial, chemigation, and groundboom applications to nurseries

,

 40 acres for airblast applications to orchards

,

 20 acres for airblast applications to nurseries

,

 40 gallons for backpack and manually

- pressurized handwand applications , and

 1000 gallons for mechanically

- pressurized handgun

.

Exposure Duration: HED typically 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 the organophosphate pesticides, the match between the toxicological endpoint selection and the exposure dura tion is different than HED’s approach for conventional chemicals. The endpoint selection for organophosphate pesticides involves a “single day” and “steady state” approach based on an

individual chemical’s cholinesterase inhibition. T he steady state approa ch is appropriate for

dimethoate given the toxicological and exposure profile. The “steady state” endpoint selection

for dimethoate overlaps HED’s traditional short

- term exposure duration endpoint selection and is

considered health protective for occupatio nal handlers that apply commercially over longer periods of time (i.e., intermediate

- term exposures).

For most agricultural uses, it is reasonable to believe that occupational handlers will not apply the same chemical every day for more than a one

- month time frame; however, there may be a large agribusiness and/or commercial applicators who may apply a produ ct over a period of weeks ( e.g., completing multiple applications for mult iple clients within a region). The available product labels for dimethoate indicate that the products can be applied anywhere from o n c e per season up to three times per season.

Mitigation/Personal Protective Equipment: Estimates of dermal and inhalation exposure were calculated for various levels of personal protective equipmen t (PPE). Results are presented for “baseline,” defined as a single layer of clothing consisting of a long sleeved shirt, long pants,

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

- exposure

- table.pdf

10 Available: http://www.epa.gov/pes ticides/science/handler

- exposure

- data.htmlPage 18 of 56



## shoes plus socks, no protective gloves, and no respirator, as well as baseline with various levels

of PPE as necessary ( e. g., gloves, respirator, etc). Most of the dimethoate registered labels require handlers to wear a single layer of clothing (long sleeved shirt and long pants), shoes plus socks, protective eyewear (either goggles or face shield ) , chemical

- resistant gloves , a NIOSH

approved dust/mist filtering respirator with MSHA/NIOSH approval number prefix TC

- 21C or a

NIOSH

- approved respirator with any N, R, P, or HE filter, and a chemical

- resistant apron when mixing, loading, cleaning up spills, or equipment.

Occupatio nal 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.

Combining Exposures/Risk Estimates

Dermal and inhalation risk estimates were com bined in this assessment, since the toxicological effects for these exposure routes were similar. It should be noted, however, that a dimethoate dermal toxicity study was used to estimate dermal risks and an omethoate inhalation toxicity study was used to estimate inhalation risks. The inhalation risk estimates are considered to be a conservative estimate of exposure to dimethoate for handlers. 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 occupational handler exposure and risk estimates indicate that the dermal and inhalation

combined MOEs ar e of concern to HED (i.e., MOE s ≤ 100 0 ) for most scenarios assuming the

use of label

- required PPE (noted by the highlighted column in Table 8 .1.1

– single layer of clothing, gloves and a PF5 respirator)

. As was noted above, the inhalation risk estimates a re considered to be a conservative estimate of exposure to dimethoate residues considering the inhalation POD was selected from an omethoate toxicity study. Only five scenarios (out of 40)

reach an MOE above the LOC of 1000 at some level of PPE (above what is currently required on the labels) or with engineering controls.

HED has no data to assess exposures to pilots using open cockpits. The only data available is for exposure to pilots in enclosed cockpits . Therefore, risks to pilots are assessed using the engineering control (enclosed cockpits) and baseline attire (long

- sleeve shirt, long pants, shoes, and socks); per the Agency’s Worker Protection Standard stipulations for engineering controls, pilots ar e not required to wear protective gloves for the duration of the application. With this level of protection, there are no risk estimates of concern for applicators.

The Agency matches quantitative occupational exposure assessment with appropriate characterization of exposure potential. While HED presents quantitative risk estimates for human flaggers where appropriate, agricultural aviation has changed dramat ically over the past two decades. According the 2012 National Agricultural Aviation Association (NAAA) survey of their membership, the use of GPS for swath guidance in agricultural aviation has grown steadily from the mid 1990’s. Over the same time period, the use of human flaggers for aerial pesticide applications has decreased steadily from ~15% in the late 1990’s to only 1% in the most recent (2012) NAAA survey. The Agency will continue to monitor all available information sources toPage 19 of 56



## best assess and char acterize the exposure potential for human flaggers in agricultural aerial applications

. HED recommends that the PPE on the registered dimethoate labels for flaggers be revised to reflect the requirements identified above (and in Table 8 .1.1) to reach acceptable MOEs, or that flaggers be prohibited on the label.Page 20 of 56

Table 8. 1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Dimethoate

.

Exposure

Scenario Crop or Target 1 Dermal Unit Exposure
(μg/lb ai) 2 Inhalation

Unit Exposure
(μg/lb ai) 2 Maximum

Application

Rate 3 Area

Treated 4 Total MOE 5 (LOC = 100 0 )

SL/No G

No

- R SL/G

No

- R DL/G

No

- R SL/No G

PF5 R SL/G

PF5

- R DL/G

PF5

- R SL/No G

PF10 R SL/G

PF10

- R DL/G

PF10

- R EC

Mixer/Loader

M/L liquids for aerial applications

and c hemigation 8 Nursery

SL/No G 220

SL/G 37.6

DL/G 29.1

EC 8.6 No

- R 0.219

PF5 R 0.0438

PF10 R 0.0219

EC 0.083 1 lb ai/A 60 A 67 130 140 98 360 420 100 450 540 610

Orchard 6 0.33 lb ai/A

350 A 34 70 74 49 190 210 52 240 280 320

1.0 lb ai/A 11 24 25 16 63 72 17 80 95 110

1.33 lb ai/A 8.6 17 18 12 46 52 13 59 69 78

Typical field crops 7 0.5 lb ai/A 22 46 48 32 120 140 34 150 190 210

1 lb ai/A 11 24 25 16 63 72 17 80 95 110

High

- acreage field

crops 0.5 lb ai/A 1200 A 6.7 13 14 9.8 36 42 10 45 54 61

Forestry (aerial only) 2 lb ai/A 7500 A 0.26 0.54 0.57 0.38 1.5 1.7 0.4 1.8 2.2 2.4

M/L liquids for

airblast applications Nursery 4.15 lb ai/A 20 A 48 100 110 68 260 300 72 330 440 440

Orchard 1.33 lb ai/A 40 A 74 150 160 110 410 470 110 510 610 690

M/L liquids for groundboom applications Nursery 0.5 lb ai/A 60 A 130 270 290 190 700 820 200 890 1

, 100 1

, 200

Typical field crops 2 lb ai/A 80 A 25 51 53 36 130 150 38 170 210 230

High

- acreage field

crops 0.5 lb ai/A 200 A 39 79 83 56 220 250 59 270 320 370

M/ L WSP for aerial applications Orchard

EC 9.8 EC 0.24 1 lb ai/A 350 A ND ND ND ND ND ND ND ND ND 42

High

- acreage field

crops 0.5 lb ai/A 1,200 ND ND ND ND ND ND ND ND ND 24

M/L WSP for

airblast applications Orchard 1 lb ai/A 40 A ND ND ND ND ND ND ND ND ND 370

M/L WSP for groundboom applications High

- acreage field

crops 0.5 lb ai/A 200 A ND ND ND ND ND ND ND ND ND 140Page 21 of 56

Table 8. 1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Dimethoate

.

Exposure

Scenario Crop or Target 1 Dermal Unit Exposure
(μg/lb ai) 2 Inhalation

Unit Exposure
(μg/lb ai) 2 Maximum

Application

Rate 3 Area

Treated 4 Total MOE 5 (LOC = 100 0 )

SL/No G

No

- R SL/G

No

- R DL/G

No

- R SL/No G

PF5 R SL/G

PF5

- R DL/G

PF5

- R SL/No G

PF10 R SL/G

PF10

- R DL/G

PF10

- R EC

Applicator

Applying sprays

via aerial equipment Nursery

EC 2.08 EC 0.0049 1 lb ai/A 60 A ND ND ND ND ND ND ND ND ND 2

, 800

Orchard 1.33 lb ai/A 350 A ND ND ND ND ND ND ND ND ND 360

Typical field crops 1 lb ai/A ND ND ND ND ND ND ND ND ND 480

High

- acreage field

crops 0.5 lb ai/A 1,200 A ND ND ND ND ND ND ND ND ND 280

Forestry 2 lb ai/A 7,500 A ND ND ND ND ND ND ND ND ND 11

Applying sprays

via airblast equipment 9 Nursery SL/No G 1,770

SL/G 1,590

DL/G 1,480

EC 14.6 No

- R 4.71

PF5 R 0.942

PF10 R 0.471

EC 0.068 4.15 lb ai/A 20 A 2.2 2.2 2.2 5.7 6.2 6.2 7.1 7.9 7.9 170

Orchard 1.33 lb ai/A 40 A 3.4 3.5 3.5 8.9 9.3 9.9 11 12 13 260

Applying sprays via groundboom equipment Nursery SL/No G 78.6

SL/G 16.1

DL/G 12.6

EC 5.1 No

- R 0.34

PF5 R 0.068

PF10 R 0.034

EC 0.043 0.5 lb ai/A 60 A 93 110 110 280 460 470 380 800 850 2

, 300

Typical field crops 2 lb ai/A 80 A 17 19 19 52 84 87 71 150 160 430

High

- acreage field

crops 0.5 lb ai/A 200 A 27 31 31 85 140 140 120 230 250 680

Flagger

Flagger Nursery

SL/No G 11

SL/G 12

DL/G 10.6 No

- R 0.35

PF5 R 0.07

PF10 R 0.035 1 lb ai/A 60 A 170 170 170 650 630 660 1

, 000 950 1

, 000 ND

Orchard 1.33 lb ai/A

350 A 22 22 22 83 81 84 130 120 130 ND

Typical field crop 1 lb ai/A 29 29 30 110 110 110 170 160 170 ND

High

- acreage field

crop 0.5 lb ai/A 59 58 59 220 220 220 340 320 350 ND

Mixer/Loader/Applicator

M/L/A liquids ground applications (soil directed) with backpack Orchard

SL/No G 8,260 SL/G 8,260 DL/G 4,120 No

- R 2.58

PF5 R 0.516

PF10 R 0.258 0.005 lb ai/gal

40 gal 710 710 1

, 200 820 820 1

, 600 830 830 1

, 600 ND

Christmas tree farm 0.025 lb ai/gal 140 140 250 160 160 320 170 170 330 ND

Forestry 0.04 lb ai/gal 92 92 150 110 110 200 110 110 200 ND

Nursery 0.08 lb ai/gal 45 45 79 51 510 100 52 52 110 NDPage 22 of 56

Table 8. 1.1. Occupational Handler Non

- Cancer Exposure and Risk Estimates for Dimethoate

.

Exposure

Scenario Crop or Target 1 Dermal Unit Exposure
(μg/lb ai) 2 Inhalation

Unit Exposure
(μg/lb ai) 2 Maximum

Application

Rate 3 Area

Treated 4 Total MOE 5 (LOC = 100 0 )

SL/No G

No

- R SL/G

No

- R DL/G

No

- R SL/No G

PF5 R SL/G

PF5

- R DL/G

PF5

- R SL/No G

PF10 R SL/G

PF10

- R DL/G

PF10

- R EC

M/L/A liquids

broadcast applications with backpack Christmas tree farm SL/No G

58400

SL/G 30500

DL/G 16900 No

- R 69.1

PF5 R 13.8

PF10 R 6.9 0.025 lb ai/gal 17 25 34 22 40 64 23 43 72 ND

Nursery 0.08 lb ai/gal 5 8 11 7 12 20 7 13 23 ND

Forestry SL/No G 8,260

SL/G 8,260 DL/G 4,120 No

- R 2.58

PF5 R 0.516

PF10 R 0.258 0.04 lb ai/gal 11 16 21 14 25 40 14 27 45 ND

M/L/A liquids foliar applications with manually

pressurized handgun Christmas tree farm SL/No G 100,000

SL/G 430

DL/G 365 No

- R 30

PF5 R 6

PF10 R 3 0.025 lb ai/gal

40 gal 13 120 130 14 550 560 14 920 970 ND

Nursery 0.08 lb ai/gal 4 39 40 4.3 170 180 4.4 290 310 ND

M/L/A liquids foliar applications with mechanically

pressurized handgun Orchard

SL/No G 6050

SL/G 2050

DL/G 1360 No

- R 8.68

PF5 R 1.74

PF10 R 0.87 0.0025 lb ai/gal 1,000 gal 61 110 130 83 210 280 88 230 330 ND Christmas tree farm

Nursery

Typical field crop

M/L/A liquids drench/soil/ground

directed applications with mechanically

pressurized handgun Orchard

Nursery

Typical field crop

Shaded column = current PPE required on labels. Bold MOE values indicate the LOC has been exceeded with label

- recommended and/or additional PPE.

1 Typical field crops include asparagus, broccoli, cauliflower, Brussel sprouts, celery, endive, leaf lettuce, Swiss chard, garbanzo beans, kale, lentils, melons, mustard greens, peas, peppers, tomatoes, turnips, and watermelon. High acreage field crops included alfalfa, beans, corn, cotton, grass grow n for seed, potatoes, sa fflower, sorghum, soybeans and wheat. Orchard crops include cherries, citrus, pears and pecans. Nurseries include citrus, lupine, ornamentals in outd oor nurseries. Forestry includes trees grown for pulp.

2 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” ( September 2015 ); Level of mitigation: SL/No G No

- R = Single layer clothing, no gloves, no respirator; SL/G No

- R = Single layer clothing, gloves, no respirator; DL/G No

- R = Double layer clothing, gloves, no respirator; SL/No G PF5 R = Single layer clothing, no gloves, PF5 respirator; SL/G PF5 R = Single layer clothing, gloves, PF5 respirator; DL/G PF5 R = Double layer cl othing, gloves, PF5 respirator; SL/No G PF10 R = Sing le layer clothing, no gloves, PF10 respirator; SL/G PF10 R = Single layer clothing, gloves, PF10 respirator; DL/G PF10 R = Do uble layer clothing, gloves, PF10 respirator; EC = Engineering Controls. ND = no data.

3 Based on registered labels.

4 Exposure Sci ence Advisory Council Policy #9.1.

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

. 6 Application rates for orchard crops: Pecans (0.33 lb ai/A); Pears and Citrus (1 lb ai/A) Cherries (1.33 lb ai/A).Page 23 of 56

7 Dimethoate 400 label (67760

- 118); Label lists m aximum application rate for Brussels Sprout as 0.5 lb ai/A, but also indicates 38.2 fl oz. product/A, which is 1 lb ai/A.

8 Only the scenarios assessed at 350 A are applicable for Chemigation applications.

9 For airblast applications to nurs eries and orchards, additional PPE could include chemical

- resistant headgear (CRH). The addition of CRH resulted in MOEs that exceed HED’s LOC: Nursery

– SL/G/CRH = 24, DL/G/CRH

– 27; Orchard SL/G/CRH = 37, DL/G/CRH

– 41.Page 24 of 56



## 8

. 2 Occupational Post

- applicat ion 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 o n such things as the type of activity, the nature of the crop or target that was treated, the type of pesticide application, and the chemical’s degradation properties. In addition, the timing of pesticide applications, relative to harvest activities, can greatly reduce the potential for post

- application exposure.

8

. 2 .1 Occupational Post

- application Inhalation Exposure/Risk Estimates

There are multiple potential sources of post

- application inhalation exposure to individuals performing post

- application activities in previously treate d 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 Inse cticide, 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 h as developed a Volatilization Screening Tool and a subsequent Volatilization Screening Analysis ( http://www.regulations.gov/#!docketDetail;D=EPA

- HQ

OPP

- 2014

- 0219 ). Durin g Registration Review, the agency will utilize this analysis to determine if data (i.e., flux studies) or further analysis is required for dimethoate

.

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

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

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

8

. 2 .2 Occupational Post

- application Dermal Exposure/Risk Estimates

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: The endpoint selection for organophosphate pesticides involves a “single day” and “steady state” approach based on an individual chemical’s cholinester ase inhibition.

T he steady state approach is appropriate for dimethoate given the toxicological and exposure profile. The “steady state” endpoint selection for dimethoate overlaps HED’s traditional short

term exposure duration endpoint selection as well as being appropriately health protective for

workers that are exposed over longer periods of time (i.e., intermediate

- term exposures).Page 25 of 56



## 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 subject to the data protection provisions of FIFRA. The standard values recommended for use in predicting post

- application exposure that are used in this assessment, known as “transfer coefficients”, are presented in the ExpoSAC Policy 3 11 

## ” which, along with
additional information about the ARTF data, can be found at the Agency website 12



## .

Application Rate: The application rate s used in this assessment are provided in Appendix C

.

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

DFR Data : Chemical

- specific DFR data have been submitted for dimethoate

. Four studies were

submitted that examined residues of dimethoate and its metabolite , omethoate, on the following

crops: grapes (MRID 44788201), tomato (MRID 44690302), lettuce (MRID 44690301) , and apple (MRID 44827601). All four studies have been reviewed by HED (see Appendix B) and found to be acceptable for risk assessment. The gra p e DFR data were not used in this risk

assessment since dimethoate is no longer registered for use on grapes.

A summary of how the DFR data were used is summarized in Table 8 .2.2.1.

Table 8 .2.2.1. Summary o f DFR D ata Use in Occupational Post

- application Assessment for Dimethoate

. Crop for which DFR

data available Locations included in study Crops for which DFR data used as surrogate

Apple Michigan (MI)

– non

- arid New York (NY)

– non

- arid Washington (WA)

– arid Cherries, Christmas trees, Forestry, Grapefruit, Lemons, Ornamentals (nursery crop), Orange, Pear, Pecan

Lettuce Pennsylvania (PA)

– non

- arid Florida (FL)

– non

- arid California (CA)

-- arid Kale, Leaf lettuce, Mustard greens, Green pea, Swiss chard, Turnip

Tomato Pennsylvania (PA)

– non

- arid Florida (FL)

– non

- arid California (CA)

-- arid Alfalfa, Asparagus, Dry beans and peas, Broccoli, Brussels sprouts, Cauliflower, Celery, Field Corn, Pop corn, Cotton, Forage crop, Bell Pepper, Potato, Safflower, Grain sorghum, Soybean, Tomato, Watermelon, Spring wheat, Winter wheat



## Data from the apple study we re used in the post

- application assessment for all tree fruit and nut

crops, Christmas trees, forestry, and ornamentals/ nursery crops . The apple data (MRID#

448276 01) represent DFR levels obtained at an application rate of 1.0 lb ai/acre. The DFR

residue s (μg/cm 2 

## ) were adjusted to account for any differences in application rates for the registered crops.

Data from the tomato study (MRID# 44690302) were used for crops with an application rate ranging from 0.33 lb ai/acre and higher (except tree and woody crops), since the data represent

non

- woody plants and DFR levels were obtained at an application rate of 0.5 lb ai/acre. For application rates other than 0.5 lb ai/acre, the DFR levels (μg/cm 2 

## ) were adjusted to account for any differences in application r ates.

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

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

- app

- exposure

- data.htmlPage 26 of 56



## Data from the lettuce study (MRID# 44690301) were used for crops with an application rate of 0.25 lb ai/acre and less, since the data represent DFR levels obtained at an application rate of

0.25 lb ai/acre. For application rates other than 0.25 l b ai/acre, the DFR levels (μg/cm 2 

## ) were adjusted to account for any differences in application rates.

Summaries of the data are provided in Appendix B

.

Each of the studies measured the amount of dimethoate residues remaining on treated leaves

followi ng applications, and also measured, when present, omethoate residues. Typically, when omethoate was present in the studies, it peaked in quantity a few days after the application, and then gradually dissipated over time. Dimethoate residues peaked immedi ately after application and dissipated over time thereafter. In general, omethoate was a significant factor in arid areas (i.e., areas where the average annual rainfall is less than 25 inches per year). Since dissipation rates at the arid sites were sign ificantly different from those at the non

- arid sites, the results are reported separately for all study sites.

As mentioned earlier, o methoate is a metabolite of dimethoate and is three times more toxicologically potent than dimethoate . Since the POD for the dermal route of exposure was chosen from a dimethoate toxicity study, a TAF of three was chosen to account for the increased potency of omethoate in exposure calculations

. A total toxic residue approach was used whereby residues of omethoate were adjusted by the TAF

, and total residues (dimethoate + adjusted omethoate) were include in exposure calculations 13 

## . In those studies where omethoate was not found, the post

- application risks were assessed using just the dimethoate residues.

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

- applicati on Non

- Cancer Dermal Risk Estimates The post

- application exposure scenarios associated with the registered uses of dimethoate are summarized in Table s 8 .2.2. 2 through 8 .2.2.4

. The results of the risk assessment for post

application exposures indicate that the location and/or the environmental conditions (i.e., arid

versus non

- arid) near the time of application influence the length of time following application

until risks are be low HED’s level of concern (i.e., MOEs are greater than or equal to 100 0 ) as does the type of plant to which the application is dir ected. For most crops, the post

- application assessment indicates that following applications in arid areas (i.e., outdoor ar eas where average annual rainfall is less than 25 inches), residues persist longer than in non

- arid areas.

For the orchard crops , using the apple DFR data , there are risks of concern for most of the high

contact post

- application activities associated with each crop (e.g., hand harvesting, handset irrigation, etc)

. Some crop /activity combinations do not reach an acceptable MOE (LOC = 100 0 ) even up to 30 days after application.

13 Total DFR, ug/cm 2 = [ (Omethoate residue, ug/cm 2 ) * TAF] + [Dimethoate residue, ug/cm 2 )Page 27 of 56



## For the field crops using the lettuce DFR data, there are risks of concer n for certain high contact activities (e.g., hand harvesting, hand weeding, etc). Some crop/activity combinations do not reach an acceptable MOE (LOC = 1000) until 7 days after application.

For the field crops using the tomato DFR data, there are ris ks of concern for certain high contact activities (e.g., hand harvesting, hand weeding, etc). Some crop/activity combinations do not reach an acceptable MOE (LOC = 1000) until 14 days after application.Page 28 of 56

Table 8 .2.2.2 . Dimethoate Occupational Post

- application Risk Estimates Using Chemical

- specific Data ( Apples/MRID 44827601 )

.

Crop Policy

Crop Group Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

APPLE STUDY DATA

MI NY WA MI NY WA MI NY WA MI NY WA

Cherry Tree,

"fruit",

deciduous 1.33 Orchard maintenance; Weeding, Hand; Bird Control; Propping 100 12 hr 1.89 2.35 2.70 0.022 0.027 0.031 920 740 640

1 3 6 1.64 1.72 1.63 0.019 0.020 0.019 1

, 100 1

, 000 1

, 100

Transplanting 230 12 hr 1.89 2.35 2.70 0.050 0.063 0.072 400 320 280

7 11 15 0.72 0.74 0.76 0.019 0.020 0.020 1

, 000 1

, 000 1

, 000

Scouting; Pruning, Hand; Training 580 12 hr 1.89 2.35 2.70 0.127 0.158 0.182 160 130 110

14 20 26 0.28 0.29 0.30 0.019 0.019 0.022 1

, 100 1

, 000 1

, 000

Harvesting, Hand 1400 12 hr 1.89 2.35 2.70 0.306 0.382 0.439 66 53 46

20 29 30 0.12 0.11 0.21 0.020 0.018 0.035 100 0 1

, 100 580

Thinning Fruit 3600 12 hr 1.89 2.35 2.70 0.787 0.982 1.128 26 21 18

27 30 30 0.05 0.10 0.21 0.019 0.042 0.089 1

, 000 480 230

Christmas

tree Tree,

"fruit",

evergreen 1 Weeding, Hand; Grading/Tagging 100 12 hr 1.42 1.77 2.03 0.016 0.021 0.024 1,200 980 860

N/A 1 2 N/A 1.59 1.71 N/A 0.018 0.020 N/A 1

, 100 1

, 000

Transplanting 230 12 hr 1.42 1.77 2.03 0.038 0.047 0.054 530 430 370

5 9 12 0.71 0.69 0.74 0.019 0.018 0.020 1

, 100 1

, 100 1

, 000

Scouting; Shaping 580 12 hr 1.42 1.77 2.03 0.095 0.119 0.137 210 170 150

12 17 23 0.27 0.30 0.29 0.018 0.020 0.019 1

, 100 1

, 000 1

, 000

Harvesting, Hand 1400 12 hr 1.42 1.77 2.03 0.230 0.287 0.330 88 70 61

18 26 30 0.12 0.12 0.16 0.020 0.019 0.026 1

, 000 1

, 100 780

Irrigation (hand set) 1900 12 hr 1.42 1.77 2.03 0.312 0.390 0.447 65 52 45

20 29 30 0.09 0.08 0.16 0.020 0.019 0.035 1

, 000 1

, 100 570

Forestry Unassigned 2 Weeding, Hand 100 12 hr 2.84 3.54 4.06 0.033 0.041 0.047 610 490 430

4 7 10 1.64 1.70 1.74 0.019 0.020 0.020 1

, 100 1

, 000 1

, 000

Transplanting 230 12 hr 2.84 3.54 4.06 0.076 0.094 0.108 270 210 190

10 15 20 0.72 0.74 0.75 0.019 0.020 0.020 1

, 100 1

, 000 1

, 000Page 29 of 56

Table 8 .2.2.2 . Dimethoate Occupational Post

- application Risk Estimates Using Chemical

- specific Data ( Apples/MRID 44827601 )

.

Crop Policy

Crop Group Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

APPLE STUDY DATA

MI NY WA MI NY WA MI NY WA MI NY WA

Pruning, Hand 580 12 hr 2.84 3.54 4.06 0.191 0.238 0.273 110 85 74

17 24 30 0.28 0.29 0.32 0.019 0.019 0.018 1

, 100 1

, 000 940

Harvesting, Seed Cone (Conifers) 1400 12 hr 2.84 3.54 4.06 0.460 0.574 0.659 44 35 31

23 30 30 0.12 0.15 0.32 0.020 0.025 0.044 1

, 000 810 390

Irrigation (hand set) 1900 12 hr 2.84 3.54 4.06 0.625 0.779 0.895 32 26 23

25 30 30 0.09 0.15 0.32 0.020 0.034 0.060 1

, 000 600 290

Harvesting, Seedling

Production 6700 12 hr 2.84 3.54 4.06 2.203 2.749 3.156 9.2 7.3 6.4

30 30 30 0.05 0.15 0.32 0.036 0.119 0.210 560 170 81

Grapefruit,
Lemon, Orange Tree,

"fruit",

evergreen 1 Orchard maintenance; Weeding, Hand; Baiting/Trapping; Weeding, Hand 100 12 hr 1.42 1.77 2.03 0.016 0.08 0.024 1,200 980 860

N/A 1 2 N/A 1.59 1.71 N/A 0.018 0.020 N/A 1

, 100 1

, 000

Transplanting 230 12 hr 1.42 1.77 2.03 0.038 0.047 0.054 530 430 370

5 9 12 0.71 0.69 0.74 0.019 0.018 0.020 1

, 100 1

, 100 1

, 000

Scouting; Pruning,

Hand 580 12 hr 1.42 1.77 2.03 0.095 0.119 0.137 210 170 150

12 17 23 0.27 0.30 0.29 0.018 0.020 0.019 1

, 100 1

, 000 1

, 000

Harvesting, Hand 1400 12 hr 1.42 1.77 2.03 0.230 0.287 0.330 88 70 61

18 26 30 0.12 0.12 0.16 0.020 0.019 0.26 1

, 000 1

, 100 780

Nursery Crop (Ornamentals,

Non

- bearing Plants) Unassigned 4.15 Harvesting, Hand; Pruning, Hand; Scouting; Container Moving; Weeding, Hand; Transplanting; Grafting; Propagating; Pinching; Tying/T raining 230 12 hr 5.89 7.34 8.43 0.157 0.196 0.225 130 100 90

15 22 29 0.75 0.73 0.72 0.020 0.020 0.019 1

, 000 1

, 000 1

, 000

Irrigation (hand set) 1900 12 hr 5.89 7.34 8.43 1.296 1.617 1.857 16 12 11Page 30 of 56

Table 8 .2.2.2 . Dimethoate Occupational Post

- application Risk Estimates Using Chemical

- specific Data ( Apples/MRID 44827601 )

.

Crop Policy

Crop Group Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

APPLE STUDY DATA

MI NY WA MI NY WA MI NY WA MI NY WA

30 30 30 0.10 0.32 0.67 0.021 0.070 0.147 950 290 140

1 Harvesting, Hand;

Pruning, Hand; Scouting; Container Moving; Weeding, Hand; Transplanting; Grafting; Propagating; Pinching; Tying/Training 230 12 hr 1.42 1.77 2.03 0.038 0.047 0.054 530 430 370

5 9 12 0.71 0.69 0.74 0.019 0.018 0.020 1

, 100 1

, 100 1

, 000

Irrigation (hand set) 1900 12 hr 1.42 1.77 2.03 0.312 0.316 0.447 65 52 45

20 29 30 0.03 0.08 0.14 0.020 0.019 0.035 1

, 000 1

, 100 570

Pear Tree,

"fruit",

deciduous 1 Orchard maintenance; Weeding, Hand; Propping 100 12 hr 1.42 1.77 2.03 0.016 0.021 0.024 1,200 980 860

N/A 1 2 N/A 1.59 1.71 N/A 0.018 0.020 N/A 1

, 100 1

, 000

Transplanting 230 12 hr 1.42 1.77 2.03 0.038 0.042 0.054 530 430 370

5 9 12 0.71 0.69 0.74 0.019 0.018 0.020 1

, 100 1

, 100 1

, 000

Scouting; Pruning, Hand; Training 580 12 hr 1.42 1.77 2.03 0.095 0.107 0.137 210 170 150

12 17 23 0.27 0.30 0.29 0.018 0.020 0.019 1

, 100 1

, 000 1

, 000

Harvesting, Hand 1400 12 hr 1.42 1.77 2.03 0.230 0.287 0.330 88 70 61

18 26 30 0.12 0.12 0.16 0.020 0.019 0.026 1

, 000 1

, 100 780

Thinning Fruit 3600 12 hr 1.42 1.77 2.03 0.592 0.738 0.848 34 27 24

25 30 30 0.05 0.08 0.16 0.019 0.032 0.067 1

, 100 630 300

Pecan Tree, "nut" 0.33 Poling; Orchard maintenance; Weeding,

Hand 100

12 hr 0.47 0.58 0.67 0.005 0.007 0.008 3,700 3,000 2,600

Harvesting, Mechanical (shaking) 190 0.010 0.013 0.015 2,000 1,600 1,400

Transplanting 230 0.012 0.016 0.018 1,600 1,300 1,100Page 31 of 56

Table 8 .2.2.2 . Dimethoate Occupational Post

- application Risk Estimates Using Chemical

- specific Data ( Apples/MRID 44827601 )

.

Crop Policy

Crop Group Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

APPLE STUDY DATA

MI NY WA MI NY WA MI NY WA MI NY WA

Pruning, Hand; Scouting 580 0.031 0.039 0.045 640 510 450

4 7 10 0.27 0.28 0.29 0.018 0.019 0.019 1

, 100 1

, 100 1

, 000

Bold MOE values are below the LOC of 1000

. Shaded cells indicate the MOE is still below the LOC 30 days after application (i.e., an REI of >30 days would be necessary t o achieve a MOE greater than the LOC).

1 DFR = Combined residues of dimethoat e and omethoate from an apple study, adjusted to account for application rate differences and for differences in toxicity of omethoate

. 2 Daily Dermal Dose = [DFR (μg/cm 2 ) × Transfer Coeffici ent × 0.001 mg/μg × 8 hrs/day ]  BW ( 69 kg).

3 MOE = POD ( 20.2 mg/kg/day) / Daily Dermal Dose.

Table 6.2.2. 3 . Dimethoate Occupational Post

- application Risk Estimates Using Chemical

- specific Data ( Lettuce/MRID 44690301

Crop Policy Crop

Group Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

LETTUCE STUDY DATA

PA FL CA PA FL CA PA FL CA PA FL CA

Kale, Leaf
Lettuce,

Mustard Green,

Swiss

Chard Vegetable, leafy 0.25 Weeding, Hand; Thinning Plants 70

12 hr 0.27 0.11 0.52 0.002 0.001 0.004 9,100 24,000 4,800

Scouting 210 0.007 0.003 0.013 3,000 7,800 1,600

Transplanting 230 0.007 0.003 0.014 2,800 7,200 1,500

Harvesting, Hand 1100 0.035 0.014 0.066 580 1,500 310

1 N/A 5 0.10 N/A 0.15 0.012 N/A 0.019 1

, 700 N/A 1

, 100

Irrigation (hand set) 1900 12 hr 0.27 0.11 0.52 0.060 0.023 0.114 340 870 180

2 1 7 0.03 0.04 0.09 0.007 0.009 0.020 2

, 800 2

, 300 1

, 000

Pea,

Green Field / row crop,

low / medium 0.16 Weeding, Hand 70

12 hr 0.17 0.07 0.33 0.001 0.001 0.003 14,000 37,000 7,500

Scouting 210 0.004 0.002 0.008 4,700 12,000 2,500

Harvesting, Hand 1100 0.022 0.009 0.042 910 2,300 480

1 N/A 3 0.06 N/A 0.16 0.008 N/A 0.020 2

, 600 N/A 1

, 000Page 32 of 56 Table 6.2.2. 3 . Dimethoate Occupational Post

- application Risk Estimates Using Chemical

- specific Data ( Lettuce/MRID 44690301

Crop Policy Crop

Group Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

LETTUCE STUDY DATA

PA FL CA PA FL CA PA FL CA PA FL CA

Irrigation (hand set) 1900 12 hr 0.17 0.07 0.33 0.039 0.015 0.073 520 1,400 280

1 N/A 6 0.06 N/A 0.08 0.013 N/A 0.017 1

, 500 N/A 1

, 200

Turnip Vegetable, "root" 0.25 Weeding, Hand; Thinning Plants 70

12 hr 0.27 0.11 0.52 0.002 0.001 0.004 9,100 24,000 4,800

Scouting 210 0.007 0.003 0.013 3,000 7,800 1,600

Harvesting, Hand 1100 0.035 0.014 0.066 580 1,500 310

1 N/A 5 0.10 N/A 0.15 0.012 N/A 0.019 1

, 700 N/A 1

, 100

Irrigation (hand set) 1900 12 hr 0.27 0.11 0.52 0.060 0.023 0.114 340 870 180

2 1 7 0.03 0.04 0.09 0.007 0.009 0.020 2

, 800 2

, 300 1

, 000

Bold MOE values are below the LOC of 1000

. 1 DFR = Combined residues of dimethoate and omethoate from a lettuce study , adjusted to account for application rate differences and for differences in toxicity of omethoate.

2 Daily Dermal Dose = [DFR (μg/cm 2 ) × Transfer Coeffici ent × 0.001 mg/μg × 8 hrs/day ]  BW ( 69 kg).

3 MOE = POD ( 20.2 mg/kg/day) / Daily Dermal Dose.

Table 6.2.2. 4 . Dimethoate Occupational Post

- application Risk Estimates Usin g Chemical

- specific Data ( Tomato/MRID 44690302

Crop Policy Crop Group

Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

TOMATO STUDY DATA

PA FL CA PA FL CA PA FL CA PA FL CA

Alfalfa, Dry Beans, Dry Peas, Forage Crop Field / row crop, low /

medium 0.5 Scouting 1100 12 hr 0.48 0.66 0.36 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.16 0.008 0.006 0.020 2

, 500 1

, 500 1

, 000

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 1 00

Asparagus Vegetable, stem / stalk 0.5 Weeding, Hand 70 12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000Page 33 of 56 Table 6.2.2. 4 . Dimethoate Occupational Post

- application Risk Estimates Usin g Chemical

- specific Data ( Tomato/MRID 44690302

Crop Policy Crop Group

Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

TOMATO STUDY DATA

PA FL CA PA FL CA PA FL CA PA FL CA

Scouting 210 0.012 0.016 0.009 1,700 1,300 2,300

Transplanting 230 0.013 0.018 0.010 1,600 1,100 2,100

Harvesting, Hand 1100 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.16 0.008 0.014 0.020 2

, 500 1

, 500 1

, 000

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 1 00

Broccoli,

Cauliflower Vegetable, head and stem

Brassica 0.5 Transplanting 230 12 hr 0.48 0.66 0.36 0.013 0.018 0.010 1,600 1,100 2,100

Scouting Thinning Plants 330 0.018 0.025 0.014 1,100 800 1,500

N/A 1 N/A N/A 0.27 N/A N/A 0.010 N/A N/A 2

, 000 N/A

Weeding, Hand 1400 12 hr 0.48 0.66 0.36 0.077 0.107 0.058 260 190 350

2 2 6 0.06 0.11 0.10 0.010 0.017 0.017 2

, 000 1

, 200 1

, 2 00

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 1 00

Scouting Harvesting, Hand Weeding, Hand 4200 12 hr 0.48 0.66 0.36 0.232 0.322 0.174 87 63 120

3 4 11 0.02 0.02 0.04 0.011 0.009 0.018 1

, 800 2

, 400 1

, 1 00

Brussels Sprouts Vegetable, head and stem

Brassica 1 Transplanting 230 12 hr 0.95 1.32 0.71 0.025 0.035 0.019 800 570 1,100

1 1 N/A 0.35 0.53 N/A 0.009 0.014 N/A 2

, 200 1

, 400 N/A

Scouting 330 12 hr 0.95 1.32 0.71 0.036 0.051 0.027 560 400 740

1 2 2 0.35 0.21 0.58 0.013 0.008 0.018 1

, 500 2

, 500 1

, 100

Irrigation (hand set) 1900 12 hr 0.95 1.32 0.71 0.210 0.291 0.157 96 69 130

3 3 10 0.05 0.09 0.09 0.010 0.019 0.020 2

, 000 1

, 100 1

, 000

Scouting Harvesting, Hand Topping 4200 12 hr 0.95 1.32 0.71 0.463 0.644 0.348 44 31 58

4 4 14 0.02 0.03 0.04 0.008 0.017 0.020 2

, 500 1

, 200 1

, 000Page 34 of 56 Table 6.2.2. 4 . Dimethoate Occupational Post

- application Risk Estimates Usin g Chemical

- specific Data ( Tomato/MRID 44690302

Crop Policy Crop Group

Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

TOMATO STUDY DATA

PA FL CA PA FL CA PA FL CA PA FL CA

Weeding, Hand

Celery Vegetable, leafy 0.5 Weeding, Hand 70

12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 210 0.012 0.016 0.009 1,700 1,300 2,300

Transplanting 230 0.013 0.018 0.010 1,600 1,100 2,100

Harvesting, Hand 1100 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.16 0.008 0.014 0.020 2

, 500 1

, 500 1

, 000

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 100

Field Corn and Popcorn Field / row crop, tall 0.5 Weeding, Hand 70

12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 210 0.012 0.016 0.009 1,700 1,300 2,300

1100 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.016 0.008 0.014 0.020 2

, 500 1

, 500 1

, 000

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 100

Cotton Field / row crop, low /

medium 0.5 Weeding, Hand 70

12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 210 0.012 0.016 0.009 1,700 1,300 2,300

Pepper, bell Vegetable, fruiting 0.33 Weeding, Hand 70

0.31 0.44 0.24 0.003 0.004 0.002 7,900 5,700 11,0 00

Scouting 210 0.008 0.011 0.006 2,600 1,900 3,500

Transplanting 230 0.008 0.012 0.006 2,400 1,700 3,200

Harvesting, Hand Tying/Training 1100 0.040 0.056 0.030 500 360 670

1 2 2 0.17 0.07 0.16 0.015 0.009 0.020 1

, 400 2

, 200 1

, 000

Irrigation (hand set) 1900 12 hr 0.31 0.44 0.24 0.069 0.096 0.052 290 210 390

2 2 5 0.06 0.07 0.08 0.009 0.016 0.019 2

, 200 1

, 300 1

, 100Page 35 of 56 Table 6.2.2. 4 . Dimethoate Occupational Post

- application Risk Estimates Usin g Chemical

- specific Data ( Tomato/MRID 44690302

Crop Policy Crop Group

Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

TOMATO STUDY DATA

PA FL CA PA FL CA PA FL CA PA FL CA

Potato Vegetable, "root" 0.5 Weeding, Hand 70

12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 210 0.012 0.016 0.009 1,700 1,300 2,300

Irrigation (hand set) 1900 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 100

Safflower Field / row crop, low /

medium 0.5 Weeding, Hand 70 12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 1100 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.16 0.008 0.014 0.020 2

, 500 1

, 500 1

, 000

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 000

Sorghum, grain Field / row crop, tall 0.5 Weeding, Hand 70

12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 210 0.012 0.016 0.009 1,700 1,300 2,300

Soybean Field / row crop, low /

medium 0.5 Weeding, Hand 70 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 1100 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.16 0.008 0.014 0.020 2

, 500 1

, 500 1

, 000

Tomato Vegetable, fruiting 0.5 Pruning, Hand Weeding, Hand 70

12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 210 0.012 0.016 0.009 1,700 1,300 2,300

Transplanting 230 0.013 0.018 0.010 1,600 1,100 2,100

Harvesting, Hand Tying/Training 1100 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.16 0.008 0.014 0.020 2

, 500 1

, 500 1

, 000

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 100

Watermelon Vegetable, cucurbit 0.5 Scouting Weeding, Hand 90 12 hr 0.48 0.66 0.36 0.005 0.007 0.004 4,100 2,900 5,400Page 36 of 56 Table 6.2.2. 4 . Dimethoate Occupational Post

- application Risk Estimates Usin g Chemical

- specific Data ( Tomato/MRID 44690302

Crop Policy Crop Group

Category Application

Rate (lb ai/A) Activities Transfer

Coefficients (cm 2 /hr ) Time Following

Application (days, unless specified) DFR 1 Dermal Dose (mg/kg/day) 2 MOE 3 (LOC = 100 0 )

Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid Non

- Arid Arid

TOMATO STUDY DATA

PA FL CA PA FL CA PA FL CA PA FL CA

Pruning, Hand Thinning Fruit

Transplanting 230 0.013 0.018 0.010 1,600 1,100 2,100

Harvesting, Hand Turning Harvesting, Mechanically

assisted Training 550 0.030 0.042 0.023 670 480 890

2 1 1 0.06 0.27 0.29 0.011 0.017 0.019 1

, 800 1

, 200 1

, 100

Irrigation (hand set) 1900 12 hr 0.48 0.66 0.36 0.105 0.146 0.079 190 140 260

2 3 7 0.06 0.04 0.09 0.014 0.010 0.019 1

, 400 2

, 100 1

, 100

Wheat (spring and winter) Field / row crop, low /

medium 0.5 Weeding, Hand 70 12 hr 0.48 0.66 0.36 0.004 0.005 0.003 5,200 3,800 7,000

Scouting 1100 0.061 0.084 0.046 330 240 440

2 2 4 0.06 0.11 0.16 0.008 0.014 0.020 2

, 500 1

, 500 1

, 100

Bold MOE values are below the LOC of 1000

. 1 DFR = Combined residues of dimethoate and omethoate from a tomato study, adjusted to account for application rate differences and for differences in toxicity of omethoate.

2 Daily Dermal Dose = [DFR (μg/cm 2 ) × Transfer Coeffici ent × 0.001 mg/μg × 8 hrs/day ]  BW ( 69 kg).

3 MOE = POD ( 20.2 mg/kg/day) / Daily Dermal Dose.Page 3 7 of 56



## Restricted Entry Interval (REI) Current product

- label REIs range from 48 hours to 24 days depending on the crop and location (i.e., arid versus non

- arid areas). Based on the current post

- application dermal exposure assessment (Tables 8 .2.2.2

– 8 .2.2.4 ), REIs of 12 hours to more than 30 days would be necessary to reach acceptable MOEs (i.e., MOEs ≥ 10 0 0) from exposure to the combined residues of

dimethoate and omethoate. Table 8 .2.2.5 provides a summary of the current REIs on product labels and the REIs based on the quantitative post

- application exposure assessment for

dimethoate which would be needed to achieve risks which were not of concern

.

Even though REIs of 12 and 24 hours are long enough for MOEs to reach the LOC of 10 0 0 for

some crops/activities, HED recommends a minim um REI of 48 hours (72 hours in arid regions)

to be protective of potential for exposure to omethoate which is known to form after application.

These REIs are in line with the 40 CFR 156.208 (c) (2) assignments for active ingredients that

are classified as Toxicity Category I for acute dermal, eye irritation, and primary skin irritat ion.

Table 8 .2.2.5 . Summary of Restricted Entry Intervals

Crop Current REI on product labels HED recommended REI

Non

- Arid Arid Non

- Arid Arid

Cherry 10 days 14 days >30 days >30 days

Christmas tree 10 days 14 days 29 days >30 days

Forestry 14 days 24 days >30 days >30 days

Grapefruit 10 days 14 days 26 days >30 days

Lemon 10 days 14 days 26 days >30 days

Orange 10 days 14 days 26 days >30 days

Nursery Crop (Ornamentals,

Non

- bearing Plants) Woody ornamentals 10 days 14 days

29 days

( >30 days if

airblast >1 lb ai/A) >30 days

( >30 days

if airblast

>1 lb ai/A) Herbaceous

ornamentals 48 hours

Conifer seed orchards 48 hours

(16 days if airblast >1 lb ai/A) 4 days

(25 days if

airblast >1 lb ai/A)

Pear 10 days 14 days >30 days >30 days

Pecan

48 hours 7 days 10 days

Kale

48 hours 1 

### 7 days Lettuce, leaf

Mustard Green

Swiss Chard

Pea, Green 48 hours 1 

### 6 days

Turnip 48 hours 1 

### 7 days

Alfalfa

3 days 7 days Asparagus

Bean, dry, and Pea, dry

Broccoli 48 hours 72 hours 4 days 11 days

Brussels Sprouts 48 hours 72 hours 4 days 14 daysPage 38 of 56



### Table 8 .2.2.5 . Summary of Restricted Entry Intervals

Crop Current REI on product labels HED recommended REI

Non

- Arid Arid Non

- Arid Arid

Cauliflower 48 hours 72 hours 4 days 11 days

Celery 48 hours 3 days 7 days

Field Corn and Popcorn 48 hours (4 days for detasseling) 48 hours (15 days

for detasseling) 3 days 7 days

Cotton 48 hours 48 hours 1 

### 72 hours 1



### Forage Crop 48 hours 3 days 7 days

Pepper, bell 48 hours 2 days 5 days

Potato 48 hours 3 days 7 days

Safflower 48 hours 3 days 7 days

Sorghum, grain 48 hours 48 hours 1 

### 72 hours 1



### Soybean 48 hours 48 hours 4 days

Tomato 48 hours 3 days 7 days

Watermelon 48 hours 3 days 7 days

Wheat (spring and winter) 48 hours 48 hours 4 days

1. Even though REIs of 12 and 24 hours are long enough for MOEs to reach the LOC of 100 for some crops/activities, HED recommends a

minimum REI of 48 hours (72 hours in arid regions) for the product labels to be protective of the acute toxicity of omethoate

.Page 39 of 56



## Appendix A. Summary of Occupational and Residential Non

- cancer Algorithms

OCCUPATIONAL NON



# - CANCER HANDLER ALGOR ITHMS



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

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

where:

E = exposure (mg ai/day),

UE = unit exposure (μg ai/lb ai),

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

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

The daily doses are calculated using the followin g formula:

ADD= E * AF

BW

where:

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

E = exposure (mg ai/day),

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

BW = body weight (kg).

Margin of Exposure: Non

- cancer risk estimates for each application handler scenario are calculated using a Margin of Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern. The daily dermal and inhalation dose received by occupational

h andlers are compared to the appropriate POD to assess the risk to occupational handlers for each exposure route. All MOE values are calculated using the following formula:

MOE= POD

ADD

where:

MOE = margin of exposure: value used by HED to represent ri sk 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 56



### OCCUPATIONAL NON



# - CANCER POST



# - APPLICATION ALGORITH MS



## 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).

DFR from chemical

- specific studies were used in the post

- application calculations. The DFR data represented both dimethoate and ometh oate residues, if both were measured in the studies. Omethoate residues, when measured, were adjusted for differences in toxicity (TAF value of 3)

and then combined with dimethoate residues to obtain a total combined residue value for use in

post

- applicat ion calculations. If omethoate was not found in the studies, only dimethoate residues were used in calculations. DFR data were also adjusted for any differences in application rates between study rates and registered label rates.

Total DFR, ug

cm 2 

## = [ ( Omethoate residue, ug

cm 2 

## ) *TAF ] + [ Dimethoate residue, ug

cm 2 

## ]

Once the DFR was calculated, post

- application exposure was calculated using the following

formula:

E=TC * DFR t 

## * ET * 0.001 mg

ug

where:

E = exposure (mg ai/day),

TC = transfer coefficient (cm 2 

## /h r),

DFR t 

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

## ), and

ET = exposure time (hours/day).

The daily doses are calculated using the following formula:

ADD= E * AF

BWPage 41 of 56



## where:

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

E = exposure (mg ai/day),

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

BW = body weight (kg).

Margin of Exposure: Non

- cancer risk estimates for each scenario are calculated using a Margin of Exposure (MOE), which is a ratio of the toxicologic al endpoint to the daily dose of concern. The daily dermal dose received by occupational post

- application workers is compared to the appropriate POD to assess the risk to occupational post

- application workers. All MOE values are calculated using the foll owing 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 42 of 56



## Appendix B. Summary of Available DFR Data for Dimethoate

MRID # 447882

- 01. Prochaska, Lee M. Dissipation of Dimethoate and its Metabolite Omethoate Dislodgeable Foliar Residues on Grapes Treated with Clean Crop® Dimethoate 400, Phase I Field Investigation & Phase I I Analytical

, March, 1999. Reviewed by HED: D254794

This study met most of the OPPTS Series 875 Group B Occupational and Residential Exposure Test Guidelines. The most important deviation was that the study was not conducted at the maximum application rate

.

The study was conducted in three geographical locations: in the California Central Valley, near Porterville, in Tulare County; in upstate New York, near Dundee, in Yates County; and in the Washington State central valley, 8 miles south of Quincy, in Grant County. At each of the test sites, two plots were established. One plot was left untreated and served as a control. The other plot was divided into 3 subplots for leaf disc collection. Sampling rows were selected to minimize edge effects and spr ay overlap. Clean Crop® Dimethoate 400 was applied to the vineyards twice during the growing season from a few days to a month after “veraison,” which is the point at which the grape enters the ripening period (i.e., “green” to mature fruit). Both applic ations were applied at 1 lb ai/A, not the label permitted maximum rate of 2 lbs ai/A. Airblast sprayers were used at all test sites. No rain events are noted in California; irrigation occurred three times (4 inches each time); these did not coincide with pesticide applications. In New York, there were 16 rain events; these did not coincide with pesticide applications. In Washington, there were 10 rain events and two irrigation events; these did not coincide with pesticide applications. Foliage samples were collected as soon as sprays had dried (e.g., no later than 4 hours postapplication), 12 hours, 1, 2, 3, 5, 7, 10, 14, 21, 28, and 35 days after the last application.

MRID# 446903

- 02. Bookbinder, M.G. Dissipation of Dislodgeable Foliar Residues of Dimethoate (O,O

- dimethyl S

- [N

- [methylcarbamoyl]methyl] phosphorodithioate) and its Metabolite Omethoate (O,O

- dimethyl S

- [2

- (methylamino)

- 2

- oxoethyl] phorphorothioate) after Application of CLEAN CROP® DIMETHOATE 400 Insecticide to Tomato Plants. October,

1 998. Reviewed by HED: D251129

This study met most of the requirements of the Environmental Protection Agency’s (US

- EPA) OPPTS Series 875, Occupational and Residential Exposure Test Guidelines, Group B: Postapplication Exposure Monitoring Test Guidelines . The following major issue was noted: residue values were calculated even for samples with concentrations below the LOQ, which may

have affected the half life calculations.

The study was conducted in three geographical locations: near Porterville in Tula re County, California; near Hobe Sound, Martin County, Florida; and near Germansville in Lehigh County, Pennsylvania. According to the 1998 Agricultural Statistics Handbook (NASS, USDA), as cited in the study report, the test states and adjacent states pro duced 78 percent of the 1997 U.S.Page 43 of 56



## tomato acreage. At each of the test sites, two plots were established. One plot, located upwind from the other, was left untreated and served as a control. The other plot was divided into 3 subplots. Sampling rows were selected to minimize edge effects and spray overlap. During the field trial, test plots were maintained according to normal regional practice for tomato culture. The test plots received 2 applications, 7 or 8 days apart, of CLEAN CROP® DIMETHOATE

400 in secticide. As prescribed on the label, the dimethoate was formulated as a 42.9 percent EC containing 4 lbs active ingredient (ai) per gallon. The dimethoate was applied at the maximum registered application rate for tomatoes of 0.5 lb ai/acre, using CO 2 

## p owered backpack boom equipment at the Florida site, and tractor

- mounted PTO

- powered groundboom equipment at the California and Pennsylvania sites. The California test plots received furrow irrigation totaling 22 inches during the trial period, but no rainf all. The Florida sites received drip irrigation totaling 2.16 inches and rain on days 4, 11, 12, and 13 after the second application. No irrigation was applied to the Pennsylvania site, but rain was recorded on days 3, 4, 5, 6, 10, 11, 12, and 14 after

t he second application

-- with a one

- day high rainfall event of 2.2 inches on day 6 after the second application. Tomato DFR leaf

- punch samples of approximately 400 cm 2 

## of surface (two

sided) were collected using a 1

- inch diameter Birkestrand leaf punch sa mpler plots prior to each application, as soon as the spray had dried (Day 0), and on days 1, 2, 3, 5, 7, 10, 14, 21, 28, and 35 after the second application. Samples collected after 14 days after the second application were not analyzed, because residues had dropped to below the limit of quantification (LOQ) by

that time.

Summary of DFR Values and EPA Regression Analysis Results for Treated Tomato with Dimethoate (MRID# 446903

- 02 ).



### Site CA PA FL

Study Target Rate (lb ai/A) 0.5 0.5 0.5

Measured Average Day 0 Residue (μg/cm 2 

### ) 0.572 0.6983 1.2107

Linear Regression Predicted Day 0 Residue (μg/cm 2 

### ) 0.357 0.476 0.661

Slope

- 0.205

- 1.008

- 0.909

Half

- life (days) 3.4 0.7 0.8

R 2 

### 0.8441 0.9117 0.7719



## MRID# 446903

- 01. Bookbinder, M. G. Dissipation of Dislodgeable Foliar Residues of Dimethoate (O,O

- dimethyl S

- [N

- [methylcarbamoyl]methyl] phosphorodithioate) and its Metabolite Omethoate (O,O

- dimethyl S

- [2

- (methylamino)

- 2

- oxoethyl] phorphorothioate) after Application of CLEAN CROP® DIMETHOATE 400 Insect icide to Leaf Lettuce. October, 1998. Reviewed by HED: D251129

T his DFR study met most of the requirements of the Environmental Protection Agency’s (US

EPA) OPPTS Series 875, Occupational and Residential Exposure Test Guidelines, Group B: Postapplication Exposure Monitoring Test Guidelines. In addition, some discrepancy and minor

issues were noted in this review.Page 44 of 56



## The study was conducted in three geographical locations: near Porterville in Tulare County, California; near Hobe Sound in Martin County, Flor ida; and near Germansville in Lehigh County, Pennsylvania. According to the 1998 Agricultural Statistics Handbook (NASS, USDA), as cited in the study report, the test states and adjacent states produced 100 percent of the 1997 U.S. leaf lettuce crop. At e ach of the test sites, two plots were established. One plot was left untreated and served as a control. The other plot was divided into 3 subplots for leaf disc collection. Sampling rows were selected to minimize edge effects and spray overlap. The tes t plots received 2 applications, 7 or 8 days apart, of CLEAN CROP® DIMETHOATE 400 insecticide. The dimethoate was formulated as a 42.9 percent EC containing 4 lbs active ingredient (ai) per gallon. The dimethoate was applied at the maximum registered app lication rate of 0.25 lb ai/acre, using CO 2 

## powered backpack boom equipment at the Florida site, and

tractor

- mounted PTO

- powered groundboom equipment at the California and Pennsylvania sites. Application equipment was calibrated prior to application. Leaf disk samples of approximately

400 cm 2 

## of surface (two

- sided) were collected from both the control and test plots prior to each application, as soon as the spray had dried (Day 0), and on 1, 2, 3, 5, 7, 10, 14, 21, 28, and 35 days after the second application. Samples collected subsequent to 14 days after the second application were not analyzed, because residues had dropped to below the limit of quantification (LOQ) by that time. Daily rainfall data were obtained onsite. Rainfall at the Florida and Pennsylvania sites during the sampling per iod totaled approximately 160 and 130% respectively of the 10 year regional precipitation avenge for the trial period. The California site received no rainfall during the study period.

Summary of DFR Values and EPA Regression Analysis Results for Treat ed Lettuce with Dimethoate (MRID# 446903

- 0 1 ).



### Site CA PA FL

Study Target Rate (lb ai/A) 0.25 0.25 0.25

Measured Average Day 0 Residue (μg/cm 2 

### ) 0.64 0.348 0.1293

Linear Regression Predicted Day 0 Residue (μg/cm 2 

### ) 0.519 0.273 0.106

Slope

- 0.247

- 1.053

- 0.995

Half

- life (days) 2.8 0.7 0.7

R 2 

### 0.9575 0.97 0.9532



## MRID# 448276

- 01. Prochaska, Lee M. Dissipation of Dimethoate and its Metabolite Omethoate Dislodgeable Foliar Residues on Apples Treated with CLEAN CROP®

DIMETHOATE 400

- Phase I: Field Investigation and Phase 2: Analytical. May 4, 1999. Reviewed by HE

D: D 256309

This study met most of the requirements of the Environmental Protection Agency’s (US

- EPA) OPPTS Series 875, Occupational and Residential Exposure Test Guidelines, Group B: Postapplication Exposure Monitoring Test Guidelines. The major deviati on was that the study was conducted using an application rate of 1.0 lb ai/acre as opposed to the label specified maximum application rate of 0.5 lb ai/acre.Page 45 of 56



## Clean Crop® Dimethoate 400 was applied using airblast sprayers twice during the growing season in August to apple trees in three locations. An application rate of 1 .0 lb. active ingredient/ Acre (a.i./A) was employed. Application equipment was calibrated prior to application. Foliage samples were collected as soon as sprays had dried (e.g., no later than 4 hours postapplication), 12 hours, 1, 2, 3, 5, 7, 10, 14, 21, 28, and 35 days after the las t application. The first study site was in Ottawa County, near Marne, Michigan; the second was in upstate New York, in Wayne County near Alton, NY; and the third site was in the Washington State central valley, in Grant County, near Ephrata, WA. In 1997, the top three U.S. apple

producing states were Washington, Michigan, and New York; these states together produced 69 percent of the total U.S. crop (USDA, Agricultural Statistics, 1997). Historical meteorological

conditions at the three sites seem to ind icate nearly normal conditions in these areas at the time of the study. There was no rainfall within 24 hours before or after application. Irrigation was applied to the plots in Washington State on the fifth day after application. Cheminova analyzed

the dissipation data using a nonlinear regression fit to a first order decay equation. Residues were still detectable 35 days after the application at all locations.

Summary of DFR Values and EPA Regression Analysis Results for Treated Apples with Dimethoa te (MRID# 448276

- 01 ).



### Site MI NY WA

Study Target Rate (lb ai/A) 1 1 1

Measured Average Day 0 Residue (μg/cm 2 

### ) 2.0062 2.1775 2.4612

Linear Regression Predicted Day 0 Residue (μg/cm 2 

### ) 1.418 1.769 2.031

Slope

- 0.137

- 0.105

- 0.085

Half

- life (days) 5.1 6.6 8.2

R 2 

### 0.9748 0.9456 0.9195Page 46 of 56



## Appendix C. Use Summary for Dimethoate

Table C.1. Summary of Registered L abels for Dimethoate

Product N a me/Formulation Regi s tr a tion No

Gowan Dimethoate E267 10163

- 56

Drexel Dimethoate 4EC 19713

- 231

Drexel Dimethoate 2.67 19713

- 232

Dimethoate 400 34704

- 207

Dimethoate 2.67 EC 34704

- 489

Dimethoate 4E 66330

- 223

Dimethoate 25 WP 66330

- 237

Dimethoate 2.67 EC 66330

- 244
Cymate 267 66330

- 245

Dimethoate 400 67760

- 118

Dimethoate 4E 67760

- 44
Agrisolutions Dimate 4E 9779

- 273
Clean Crop Dimethoate 400 CA970003

Dimethoate 4E ID110008

Dimethoate 400 ID120004 Clean Crop Dimethoate 400 ID980006
Dimethoate 400 OR050019Page 47 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Agricultural

uncultivated areas (Noncropland adjacent to vineyards) Groundboom/

Handgun application Liquid 2 lb ai/A

0.0025 lb ai/gal (Mech HG) NS NS 2 per year NS NS

Alfalfa (field and seed crop) Aerial,

Groundboom, Chemigation Liquid 0.5 lb ai/A 0.5 lb ai/A NS

30 1 per crop

cycle or cutting; 3 per

year 48 hours 10

Asparagus Aerial,

Groundboom, Chemigation Liquid 0.5 lb ai/A 1 lb ai/A NS

14 2 48 hours 180

Beans (fresh, snap, lima, dry, not cowpeas) Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.5 lb ai/A 1 lb ai/A NS

14 2 48 hours NS

0

2

Broccoli,

Cauliflower Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.5 lb ai/A 1.5 lb ai/A 7 3 48 hours; increased to 72 hours

in outdoor areas where the average annual rainfall is less than 25 inches per year. 7

Brussel sprouts Aerial,

Groundboom, Chemigation (some

labels restrict aerial and chemigation) Liquid 0.5 lb ai/A a 1.5 lb ai/A 7 3 48 hours; increased to 72 hours

in outdoor areas where the avenige annual rainfall is less than 25 inches per year. 10Page 48 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Celery Aerial,

Groundboom, Chemigation Liquid 0.5 lb ai/A 1.5 lb ai/A 7 3 48 hours 7

Cherries (preharvest and postharvest) Aerial, Airblast, Chemigation Liquid 1.33 lb ai/A 1.33 lb ai/A NS NS 10 days; increased to 14 days in outdoor areas where the average

annual rainfall is less than 25 inches per year. 21 b

Christmas tree

nurseries Aerial, Airblast,

Chemigation, Handheld; Soil injectors (some

labels restrict aerial and chemigation) Liquid 1 lb ai/A

0.025 lb ai/gal

0.0025 lb ai/gal (Mech HG) 3 lb ai/A 14 3 10 days; increased to 14 days in outdoor areas where the average

annual rainfall is less than 25 inches per vear NA

Citrus

- non

- bearing and nursery stock Aerial, Airblast, Chemigation, Handheld (some

labels restrict aerial and chemigation) Liquid 1 lb ai/A

foliar spray: 0.005

lb ai/gal

0.0025 lb ai/gal (Mech.HG)

soil drench: 2 lb

ai/A 1 lb ai/A NS NS 10 days; increased to 14 days in outdoor areas where the average

annual rainfall is less than 25 inches per vear NAPage 49 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Citrus (grapefruit, kumquat, lemons, limes, oranges pummelo, t a ngelo, and tangerines) Aerial, Airblast,

Chemigation, Handheld (some

labels restrict aerial and chemigation) Liquid 1 lb ai/A 1 lb ai/A NS NS

no more than 2 apps to

mature fruit 10 days; increased to 14 days in

outdoor areas where the average

annual rainfall is less than 25 inches per vear 15

- 45 (depending on pest)

Corn (field and popcorn) Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.5 lb ai/A 0.5 lb ai/A NS NS

3 48 hours; 4 days for detasseling

tasks in nonarid areas and 15 days in outdoor areas where the average annual rainfall is less than 25 inches per year. 14 c

14 (forage)

14 (grain)

28 (grain)

28 (forage)

42 (grain)

Cotton Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.5 lb ai/A 1 lb ai/A 14

14 when

water is

used for dilution;

40 when

once refined vegetable

oil is used

for

dilution. 2 48 hours 14Page 50 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Endive, Leaf lettuce, Swiss chard Aerial, Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.25 lb ai/A 0.75 lb ai/A 7 3 48 hours 14

Garbanzo beans Aerial,

Groundboom, Chemigation Liquid 0.5 lb ai/A 1 lb ai/A 14 2 48 hours 0

2

Grass grown for

seed Aerial,

Groundboom, Chemigation Liquid 0.5 lb ai/A 1 lb ai/A 90 NS 48 hours NS

14

Kale Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.25 lb ai/A

(Label 66330

- 244: indicates 1.5 pt/A = 0.5 lb ai/A) 0.5 lb ai/A 15 2 48 hours 14

Lentils Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.5 lb ai/A 1 lb ai/A NS

7 2 48 hours 0

2

14

Lupine Aerial,

Groundboom, Chemigation,

Handheld Liquid 0.5 lb ai/A

0.0025 lb ai/gal (Mech HG) 1 lb ai/A 14 2 48 hours 0

Melons Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.5 lb ai/A 1 lb ai/A NS

7 NS

2 48 hours 3Page 51 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Mustard greens Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.25 lb ai/A 0.5 lb ai/A 9 2 48 hours 14

Ornamentals in

outdoor nurseries Aerial, Airblast, Chemigation, Handheld; Soil injectors (some

labels restrict aerial and chemigation) Liquid 4.15 lb ai/A (airblast)

1 lb ai/A

0.08 lb ai/gal

0.0025 lb ai/gal (Mech.HG)

soil drench: 0.06 lb ai/gal and 5.5

lb ai/A

soil injection:

0.004 lb ai/inch of

tree
circumference 4.15 lb ai/A

(airblast only)

3 lb ai/A 14 3 woody ornamentals: 10 days; increased to 14 days in outdoor areas where the average annual rainfall is less than 25 inches per

year

herbaceous ornamentals: 48

hours

conifer seed orchards: 48 hours (16 days if airblast >1 lb ai/A); increased to 4 days (25 days if airblast >1 lb ai/A) in outdoor areas where the average annual rainfall is less than 25 inches per

year NAPage 52 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Ornamentals in

outdoor nurseries

(trees grown for pulp

-- forestry) Aerial, Airblast, Chemigation, Handheld; Soil injectors Liquid 2 lb ai/A

0.04 lb ai/gal

0.0025 lb ai/gal (Mech HG)

soil injection:

0.0025 lb ai/inch

tree
circumference 6 lb ai/A NS 3 14 days; increased to 24 days in outdoor areas where the average

annual rainfall is less than 25 inches per year. NA

Pears (including

non

- bearing and nursery stock) Aerial, Airblast,

Chemigation, Handheld (some

labels restrict chemigation) Liquid 1 lb ai/A

0.005 lb ai/gal;

0.0025 lb ai/gal (Mech HG) 1 lb ai/A NS NS 10 days; increased to 14 days in

outdoor areas where the average annual rainfall is less than 25 inches per vear 28

Aerial, Airblast WSB 1 lb ai/A 1 lb ai/A

Peas Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.16 lb ai/A 0.16 lb ai/A NS

7 NS 48 hours 0

2

Peas (dry; some

labels limit to those in ID, OR and WA only) Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.33 lb ai/A

0.5 lb ai/A (allowed on SLN) 0.5 lb ai/A NS

7 NS

3 d 48 hours 0

5

- 14 dPage 53 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Peas (succulent;

some labels limit to those in ID, OR and WA only) Aerial,

Groundboom, Chemigation (some

labels restrict chemigation) Liquid 0.33 lb ai/A

0.5 lb ai/A (allowed on SLN) 0.5 lb ai/A NS

7

14 NS

3 e 48 hours NS

5

- 14 e

Pecans Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.33 lb ai/A 0.33 lb ai/A NS NS 48 hours 21

Peppers Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.33 lb ai/A 1.65 lb ai/A 7 5 48 hours NS

0

2 f

Potatoes Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid

0.5 lb ai/A 1 lb ai/A 7 2 48 hours NS

0

2 g

Aerial,

Groundboom WSB

Safflower Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.5 lb ai/A 0.5 lb ai/A NS

14 NS

1

2 at lower

rate h 48 hours 14 hPage 54 of 56

Table C. 2 . Summary of Use Directions for Dimethoate.

Crop Applic. Timing,

Type, and Equip. Formulation Maximum Application Rate Max

Seasonal Applicatio

n Rate RTI

(days) Max No.

Apps per

Season REI PHI (days)

Sorghum Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.5 lb ai/A 1 lb ai/A 7 2 48 hours 28

Soybeans Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.5 lb ai/A 1 lb ai/A 7 2 48 hours 21

28 i

Tomatoes Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.5 lb ai/A 1 lb ai/A 6 2 48 hours 7

Turnip Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.25 lb ai/A 1.75 lb ai/A 3 7 48 hours 14

Watermelon Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.5 lb ai/A 1 lb ai/A 7 2 48 hours 3

Wheat Aerial, Airblast,

Chemigation (some

labels restrict aerial and chemigation) Liquid 0.5 lb ai/A 0.5 lb ai/A NS 2 (at lower rates) 48 hours 35

45

60

a. Label 67760

- 118:directions state max of 0.5 lb ai/A, but also indicate 38.2 fl oz/A = 1 lb ai/A

b. Label 66330

- 223 lists the PHI as 21 days; but then also says interval b/t last app and harvest is 28 days

c. Labels listed various PHI's; not clear if which are correct.

d. M ax # apps and PHI listed on SLNPage 55 of 56 e. M ax of 3 apps listed on label 67760

- 118; PHI listed on SLNs

f. Labels 66330

- 244 and 66330

- 245 list PHI of 2 days

g. Labels 66330

- 244 and 66330

- 245 list PHI of 2 days

h. A couple of labels (e.g., 34704

- 489) list RTI of 14 days and no more than 2 apps

i. One label (67760

- 118) listed a longer PHIPage 56 of 56



## Appendix D. Spray Drift Calculations (see excel files)