# US Environmental Protection Agency

Office of Pesticide Programs

Revised Interim Reregistration

Eligibility Decision s for Dimethoate

This document contains the following:

Revised LABEL TABLE for Dimethoate IRED to include:

Memorandum - Revised LABEL TABLE for Dimethoate IRED - October 30, 2008

Labeling Changes Summary Table (revised October 6, 2008)

Revised Dimethoate IRED to include:

Memorandum - Revised Dimethoate IRED - August 20, 2007

Memorandum - Response to Public Comments on the Dimethoate RED - February 2, 2007

Revised Dimethoate Label Table - (for DCI 2008) which replaces the previous

version of the label table dated August 17, 2007. The August 17 version had errors on

pages 10 - 11 (see below) which are correct in this April 23, 2008 version.*

Memorandum - Finalization of IRED/TRED for Organophosphate Pesticides - July 31, 2006

Dimethoate IRED - June 12, 2006

* This label table corrects page 10, the entry for Succulent peas, by adding a sentence: “Not for use on field peas.”

The label table also corrects page 11, the entry for Cottonwood (grown for pulp), by correcting the maximum

application rate at 2 lbs a.i./A, and the maximum total rate per year at 6 lbs a.i./A. The date on the first page of

this label table has been revised to read: (for DCI 2008), to avoid confusion with the previous label table, dated

August 17, 2007.

### UNITED S TATE S ENVIRONMENTAL P R OTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF

PREVENTION, PE STICIDES

AND TOXIC SUBS TANCES



### October 30, 2008

MEMORANDUM

SUBJECT: Revised LABEL TABLE for Di m e thoate IRED

TO: Di m e thoate Docket (EPA-HQ-OPP- 2005-0084)

This m e m or a ndum makes two changes on page 8 and two clarifications to the dim e thoate

label table. All dim e thoate labels have been rev i sed to reflec t thes e chan ges and

clar if ication s. This Octo ber 6 vers io n of the labe l tab l e re m oves the prohibition on use on

citrus in Florida and also rem oves the prohi bition on aerial applica tion for citrus crops.

These prohibitions were required in the RED a nd ref l ected in all p r eviou s labe l tab l e s.

Prior to the issuance of the RE D, the risk assessm e nt indicat ed drinking water risks from

use of dim e t hoate on citrus and there wa s no reported use or need. Follow i ng the

issuance of the RED, infestations of an exot ic pest, the Asian citrus psyllid, which is a

vector of citrus greening disease, becam e es tablished in Florida citrus groves. Growers

requested the use of dimethoate for this pe st. EP A conducted a revised risk assessm ent

for aerial and ground use at the re quested rate and determ ined that the risk for potential

drinking water contam ination is below the leve l of concern. For m o re inform ation on the

need for this use and the risk as sessm ent asso ciated with the use on citrus, please refer to

the dim e thoate docket.

Two clarifications were needed to the previous label table.

 The f i rst c l a r if ica tion is that the term “ Succulent peas” has been replaced by

“ Peas” , a general term that covers all peas. The only peas that are not cov e red are

field peas, and all the labels already have the disclaim er " Not for use on fie l d

peas ".

 The second clarification is that the phrase " Bean s (including fresh, snap , lima,

and dry beans) " has been revised to read " Beans (including fresh, snap, lima,

and dry beans and excluding cowpeas)." Cowpeas are actually a b ean variety,

and are not a supported use.

To avoid confusion with previous versions, the first page of this label table states

“Revised October 6, 2008”.

The com p lete dim ethoate IRED, original a nd revised versions, with the Response to

Public Comm ents and associated docum e nts, can be found at:

http://www.epa.gov/pesticides/r eregistration/dimethoate/Labeling Changes Summary Table(revised October 6, 2008)In order to be eligible for reregistration, amend all product labels to incorporate the riskmitigation measures outlined in Section IV.The following table describes how language on the labels should be amended.DescriptionAmended Labeling LanguagePlacement on LabelFor all ManufacturingUse Products“Onlyforformulation into an insecticide for the following use(s) [alfalfa,alfalfa for seed, asparagus, beans (excluding cowpeas), broccoli, Brusselssprouts, cauliflower, celery,cherries,Christmas tree farms, coniferseedfarms, cotton, endive, fieldcorn, grass grownfor seed, herbaceousornamentals incommercialnurseries or greenhouses, grapefruit, leaflettuce (except head lettuce), lemons, lentils, kale, melons, mustardgreens, oranges, pears, peas, pecans, peppers, popcorn, potatoes,safflower, sorghum, soybeans, Swiss chard, tangerines, tangelos,tomatoes, turnips, watermelons, wheat, cottonwoodgrown for pulp, andwoodyornamentals in commercial nurseries or greenhouses].”“Not for formulation intowettable powder end use products (EUP),unless the EUP is packaged in water soluble bags.”“Not for formulation intoend-use products intended for use byhomeownersor that permituse at residential sites.”Directions for UseOne of these statementsmaybe addedto a labelto allow reformulationof the product for aspecific use or alladditional usessupported byaformulator or user“This productmaybe usedto formulateproducts for specific use(s) notlisted on theMP label if the formulator, user group,orgrower hascomplied with U.S. EPA submission requirements regarding support ofsuch use(s).”“This productmaybe usedto formulateproducts for anyadditionaluse(s) not listed on the Manufacturing Use Product (MUP) label if theformulator, user group, orgrower has complied with U.S. EPADirections for Use1groupsubmission requirements regarding support of such use(s).”Environmental HazardsStatements Requiredbythe RED andAgencyLabel Policies“Do not discharge effluent containing thisproduct intolakes, streams,ponds, estuaries, oceans, orother watersunless in accordance with therequirementsof a National Pollution Discharge Elimination System(NPDES) permit and the permitting authorityhas been notified inwritingprior todischarge.Do notdischarge effluent containing this product tosewer systems without previouslynotifying the local sewage treatmentplant authority.Forguidance contact your State Water Board orRegional Office of the EPA.”Precautionary StatementsEnd Use Products Intended for Occupational UsePPE RequirementsEstablished by theRED1For Wettable PowderFormulations (wettablepowder productsmustbe packaged in watersoluble bags tobeeligible forreregistration)“Personal Protective Equipment (PPE)”“Somematerials that are chemical-resistant to this product are”(registrant insertscorrect chemical-resistant material).“Ifyou wantmore options, follow the instructions forcategory”[registrant insertsA,B,C,D,E,F,G,or H]“on an EPA chemical-resistancecategoryselectionchart.”“Mixers, loaders, applicators, flaggers, and other handlersmust wear:> Long-sleeved shirt and longpants,> Shoes plussocks,> Chemical-resistant gloves,> a NIOSH-approveddustmist filtering respirator withMSHA/NIOSHapproval number prefix TC-21Cora NIOSH-approved respirator withanyN, R,P,or HE filter, and> Chemical-resistant apron when mixing,loading, cleaning up spills, orequipment.”“See Engineering Controlsfor additional requirements and exceptions.”Instruction toRegistrant:Drop the “N” type filter fromthe respiratorImmediatelyfollowing/belowPrecautionary Statements:Hazards toHumans and DomesticAnimals2statement, if the pesticide product contains, or is usedwith, oil.PPE RequirementsEstablished by theRED1For LiquidFormulations“Personal Protective Equipment (PPE)”“Somematerials that are chemical-resistant to this product are”(registrant insertscorrect chemical-resistant material).“Ifyou wantmore options, follow the instructions forcategory[registrant insertsA,B,C,D,E,F,G,or H]on anEPA chemical-resistancecategoryselectionchart."“Mixers, loaders, applicators, flaggers, and other handlersmust wear:> Long-sleeved shirt and longpants,> Shoes plussocks,> Chemical-resistant gloves,> a NIOSH-approveddustmist filtering respirator withMSHA/NIOSHapproval number prefix TC-21Cora NIOSH-approved respirator withanyN, R,P,or HE filter, and> Chemical-resistant apron when mixing,loading, cleaning up spills, orequipment.”“See Engineering Controlsfor additional requirements and exceptions.”Instruction toRegistrant:Drop the “N” type filter fromthe respiratorstatement, if the pesticide product contains, or is usedwith, oil.Immediatelyfollowing/belowPrecautionary Statements:Hazards toHumans and DomesticAnimalsUser SafetyRequirements“Follow manufacturer'sinstructions forcleaning/maintaining PPE.If nosuch instructions for washables exist,use detergent and hot water.Keepand wash PPE separatelyfromother laundry.”“Discard clothing and other absorbentmaterials that have been drenchedor heavilycontaminated with this product’sconcentrate.Do not reusethem.”Precautionary Statements:Hazards toHumans and DomesticAnimalsimmediatelyfollowing thePPErequirementsEngineering Controls:(Water-Soluble“Engineering controls”Precautionary Statements:Hazards toHumans and DomesticAnimals3Packaging for WettablePowder Formulations)“Pilotsmust use an enclosed cockpitthatmeets the requirements listed inthe Worker Protection Standard (WPS) for agricultural pesticides[40CFR 170.240(d)(6)].Pilotsneed not wear the PPE required in thislabeling for applicators, but mustwearat least a long-sleeve shirt, longpants, shoes, and socks.”“When applicators use enclosedcabs in a manner that meets therequirementslisted in theWorker Protection Standard(WPS) foragricultural pesticides (40 CFR 170.240(d)(5), the handler PPErequirementsmaybe reduced or modifiedas specifiedin the WPS.”(Immediatelyfollowing PPE and UserSafetyRequirements.)“Water-soluble packets, when used correctly, qualifyas a closedmixing/loading systemunder the Worker Protection Standard forAgricultural Pesticides[40CFR 170.240(d)(4)].Mixers and loadersusing water-soluble packetsmust:-- wear the personal protective equipment required in the PPE section ofthis labeling for mixersand loaders,except no respirator is required; and-- be provided and have immediatelyavailable for use in an emergency,such as a broken package, spill, or equipment breakdown:chemicalresistant footwear, and the type of respirator specifiedin the PPE sectionof this label.”Engineering Controls:For LiquidFormulations“Engineering controls”“Mixers and loaders supporting aerial application to alfalfa, cotton,soybeans, corn, safflower, sorghum, and wheatmust use a closed systemthat meets the requirements listed in theWorker Protection Standard(WPS) for agricultural pesticides [40 CFR 170.240(d)(4)]. The systemmust be capable of removing the pesticide fromthe shippingcontainerand transferring it into mixing tanks and/or application equipment.Atanydisconnect point, the systemmust beequipped with a drydisconnector drycoupleshut-off devicethat is warranted bythemanufacturertominimize drippage to nomore than 2ml per disconnect.In addition,mixers and loadersmust:Precautionary Statements:Hazards toHumans and DomesticAnimals(Immediatelyfollowing PPE and UserSafetyRequirements.)4-- wear the personal protective equipment required onthis labeling formixers/loaders, except no respirator is required;– wear protective eyewear, if the systemoperates under pressure; and-- be provided and have immediatelyavailable for use in an emergency,such as a broken package, spill, orequipment breakdown, chemicalresistant footwear and a respirator of the type specified in the PPE sectionof this labeling.”“Pilotsmust use an enclosed cockpitthatmeets the requirements listed inthe Worker Protection Standard (WPS) for agricultural pesticides[40CFR 170.240(d)(6)].Pilotsneed not wear the PPE required in thislabeling for applicators, but mustwearat least a long-sleeve shirt, longpants, shoes, and socks.”“When handlers use closedsystems,or enclosed cabs in a manner thatmeets the requirements listed in the Worker Protection Standard (WPS)for agricultural pesticides (40 CFR 170.240(d)(4-5), the handler PPErequirementsmaybe reduced or modifiedas specifiedin the WPS.”User SafetyRecommendations“USER SAFETY RECOMMENDATIONS”“Users should wash hands before eating, drinking, chewing gum, usingtobacco, or using the toilet.”“Users should remove clothing/PPE immediatelyif pesticide gets inside.Then wash thoroughlyandput onclean clothing.”“Users should remove PPE immediately after handling this product.Wash the outside of glovesbefore removing.As soon as possible, washthoroughly and change intoclean clothing.”Precautionary Statements under:Hazards to Humans and DomesticAnimals immediatelyfollowingEngineering Controls(Must be placed in a box.)Environmental Hazards“Do not apply directlytowater, or to areas where surface water ispresentor to intertidal areas belowthe mean high watermark.Do notcontaminatewater when disposing of equipment washwater or rinsate.”Precautionary Statements immediatelyfollowing the User SafetyRecommendations5“Dimethoate is known to leach throughsoil intoground water undercertain conditions as a result of label use.Use of this chemical in areaswhere soils are permeable, particularlywhere the water table is shallow,mayresult inground-water contamination.”“This productmaycontaminate water throughdrift ofsprayinwind.This product has a high potential for runoff for several daysafterapplication after application.Poorlydraining soils and soils with shallowwater tables aremore prone to produce runoff that contains this product.”“A level, wellmaintained vegetative buffer strip between areas to whichthis product isapplied andsurfacewaterfeatures suchas ponds, streams,and springs will reduce the potential forcontamination of water fromrainfall-runoff.Runoffof this product will be reduced byavoidingapplications when rainfall is forecasted to occur within48hours.”“A vegetative filter strip constructed and maintained in accordancewiththe 2000 Natural Resources Conservation Service publication“Conservation Buffers to Reduce Pesticide Losses”( http://www.nrcs.usda.gov/feature/buffers/) will significantlyreduce thepotential forcontamination of water fromrainfall-runoff.”Restricted-EntryIntervals for productswith directions for usewithin the scope of theWorker ProtectionStandard (WPS) forAgricultural Pesticides(WPS)“Do not enter or allow worker entry into treated areasduring therestricted entry interval (REI).”In the Agricultural Use Requirementsbox“PPE required for earlyentry to treatedareas that is permitted under the6Worker Protection Standardand thatinvolves contact with anything thathas been treated, such as plants, soil, orwater, is:> chemical-resistant gloves made of anywaterproofmaterial,> chemical-resistant footwear plus socks, and> chemical-resistant headgear (if overhead exposure)”Direction for UseAgricultural Use Requirements boxDouble NotificationStatement“Notifyworkers of the application bywarning themorallyand bypostingwarning signs at entrancesto treated area.”Direction for UseAgricultural Use Requirements boxGeneral ApplicationRestrictions“Do not apply this productin a waythat will contact workers or otherpersons, either directlyor through drift.Only protected handlers maybein the area during application.”Place in the Direction for Use directlyabove the Agricultural Use Box.ApplicationRestriction“This productis for useincommercial setting only.Use in residentialsettings is prohibited.”Near the beginningof theDirections forUseEarly Entry PersonalProtective Equipmentfor products withdirections for usewithin the scope of theWorker ProtectionStandard (WPS) forAgricultural Pesticides> coveralls worn over long-sleeve shirt and long pants,Crop-SpecificApplicationRestrictions and REIsThemaximumapplication rate alsomust be statedin termsof the poundsorgallons of formulationLabelsmustbe amended to reflectthe following equipment restrictions,maximumapplication rates, retreatmentinterval, andthe maximumseasonal treatment rates:High Pressure Handwand Equipment:"When applications are madebyhigh pressure handwand equipment,the maximum application rate forall crops and use-patterns is 0.0025 pounds active ingredient per gallon."Alfalfa (grown forseed andforhay),Safflower, and Wheat:Maximumsingle application rate: 0.5 lba.i./A.Maximum total ratepercrop cycle orcutting:0.5 lba.i./A.“TheREI is 48 hours.”Directions for Use associated with theuse directions for the specific crop towhich the restriction pertains7Cherries:Maximumapplication rate: 1.33 lbs a.i./A.Maximumtotalrate per year:1.33 lbs a.i./A.“The REI is 10 days; however, the REI isincreased to 14 daysinoutdoor areas where the average annual rainfall isless than 25 inches per year.”Citrus:Maximumapplication rate: 1 lb a.i./A.Maximum total rateperyear:1lb a.i./A.“The REI is 10 days;however, the REI is increased to14 daysin outdoor areas where the average annual rainfall is less than 25Asparagus, Beans (including fresh, snap, lima, and dry beans andexcluding cowpeas) and Cotton:Maximumsingle application rate: 0.5lb a.i./A., 14dayretreatment interval.Maximumtotal rate per season:1lb a.i./A. “The REI is 48 hours.”Field Corn and Popcorn:Maximumapplication rate: 0.5 lb a.i./A.Maximumtotal rate per year:0.5 lb a.i./A.“The REI is 48 hours.PROHIBITION: Workersare prohibited fromentering the treated area toperformdetasseling tasks for 4 daysin nonarid areas and for15 days inoutdoor areas where the average annualrainfall is less than 25inches peryear.”Broccoli, Brussels Sprouts, and Cauliflower:Maximumapplicationrate: 0.5 lb a.i./A., 7 dayretreatmentinterval.Maximumtotal rate peryear:1.5 lbsa.i./A. “The REI is 48 hours; however, the REI is increasedto 72hours inoutdoor areas where the average annual rainfall is less than25 inches peryear.”Celery:Maximumapplication rate: 0.5lb a.i./A., 7dayretreatmentinterval.Maximumtotal rate per year:1.5 lbs a.i./A.“The REI is 48hours.”8inches per year.”Conifer SeedOrchards:Maximumapplication rate: 1 lb a.i./A.Maximumtotal rate per year:1 lb a.i./A.“The REI is 48 hours;however, the REI is increased to 4 daysin outdoor areas where theaverage annual rainfall is less than 25 inches per year.”Special Exception for airblast applications to Douglas Fir SeedOrchards in WA and OR only:Maximum application rate: 4.15lbsa.i./A.Maximum total rateper year: 4.15 lbs a.i./A.“If airblastapplications are applied at a rate greater than 1 lb a.i/A., the REI is 16days;however, the REI is increased to25 daysinoutdoor areas where theaverage annual rainfall is less than 25 inches per year.”Grass Grownfor SeedMaximumapplication rate: 0.5 lba.i./A., 90 dayretreatment interval.Maximumtotal rate per year:1 lb a.i./A.“The REI is 48 hours.”Herbaceous OrnamentalsMaximumapplication rate: 0.25 lb a.i./A.Maximumtotal rate per year:0.25 lba.i./A.“The REI is 48 hours.”KaleMaximumapplication rate: 0.25lb a.i./A., 15dayreapplication interval.Maximumtotal rate per year:0.5 lba.i./A.“The REI is 48 hours.”Leaf lettuce,Swiss Chard,Endive and EscaroleMaximumapplication rate: 0.25lb a.i./A., 7 dayreapplication interval.Maximumtotal rate per year:0.75 lba.i./A.“The REI is 48 hours.”9Lentils, Melon, Honeydew, andPotatoesMaximumapplication rate: 0.5 lba.i./A.,7 dayreapplication interval.Maximumtotal rate per year:1 lb a.i./A.“The REI is 48 hours.”Sorghum, and SoybeansMaximumapplication rate: 0.5 lba.i./A.,7 dayreapplication interval.Maximumtotal application rate per year:1 lb a.i./A.“The REI is 48hours.”Mustard GreensMaximumapplication rate: 0.25lb a.i./A., 9 dayreapplication interval.Maximumtotal rate per year:0.5 lba.i./A.“The REI is 48 hours.”Pears:Maximum application rate: 1 lba.i./A.Maximum totalapplication rate per year:1 lb a.i./A.“The REI 10 days;however, theREI is increased to 14days in outdoor areas where the average annualrainfall is lessthan 25 inches per year.”PecansMaximumapplication rate: 0.33 lb a.i./A.Maximumtotal rate per year:0.33 lba.i./A.“The REI is 48 hours.”PeppersMaximumapplication rate: 0.33lb a.i./A., 7 dayreapplication interval.Maximumtotal rate per year:1.65 lbs a.i./A.“The REI is 48 hours.”PeasMaximumapplication rate: 0.16 lb a.i./A.Maximumtotal rate per year:0.16 lb a.i./A. “The REI is 48 hours.”“Not for use on field peas.”10Note:There are SLN registrations for succulent peas for which the totalseasonal rateis not to exceed 0.5 lbs. a.i./acre.TomatoesMaximumapplication rate: 0.5 lba.i./A.,6 dayreapplication interval.Maximumtotal rate per year:1.0 lba.i./A.“The REI is 48 hours.”TurnipsMaximumapplication rate: 0.25lb a.i./A., 3 dayreapplication interval.Maximumtotal rate per year:1.75 lbs a.i./A.“The REI is 48 hours.”Cottonwood(grown for pulp)Maximumapplication rate: 2 lbs a.i./A.Maximumtotal rate per year: 6lbs a.i./A.“The REI is 14days;however, the REI is increased to 24 daysin outdoor areas where the average annual rainfall is less than 25 inchesper year.”Woody Ornamentals and Christmas TreeNurseries“Maximumapplication rate: 1.0 lb a.i./A., 14 dayreapplication interval.Maximumtotal rate per year:3.0 lbs a.i./A. “When applications aremade byhigh pressure handwand equipment,the maximumapplicationrate for all crops and use-patterns is0.0025 pounds active ingredientpergallon.” “The REI is 10 days;however, the REI is increased to 14 daysinoutdoor areas where the average annualrainfall is less than 25inches peryear.”SprayDriftRequirements for Reducing Spray DriftDo not applyunder circumstanceswhere possible driftto unprotectedpersons or tofood, forage, or otherplantings that might be damaged orcrops thereof rendered unfit for sale, use, or consumption can occur.Directions for Use111.Use the largest droplet size consistentwith acceptable efficacy.Formation ofverysmall dropletsmaybeminimized by appropriatenozzle selection, by orienting nozzles awayfromthe air streamasmuchas possible, and by avoiding excessive sprayboompressure.Forgroundboomand aerial applications, usemediumor coarser spraynozzles according toASAE 572definition for standardnozzles or avolumemeandiameter (VMD) of 300microns or greater for spinningatomizer nozzles.2.Make aerial or ground applications when the windvelocity favors ontarget productdeposition.Applyonlywhen the windspeed is less thanor equal to10mph.For all non-aerial applications, wind speed must bemeasured adjacent to the application site on the upwind side, immediatelyprior to application.3.Do not make aerial or groundapplications intoareas of temperatureinversions.Inversions are characterizedbystable air and increasingtemperatureswith increasing distance above the ground.Mist orfog mayindicate the presenceof an inversion inhumid areas.Where permissiblebylocal regulations, the applicator maydetect the presence of aninversion byproducing smoke andobserving a smoke layer near theground surface.4.Low humidityandhightemperaturesincrease the evaporation rate ofspraydroplets and therefore the likelihood of increased spraydrift.Avoid spraying during conditions oflowhumidityand/or hightemperatures.5.All aerial and ground application equipmentmust be properlymaintained and calibrated using appropriate carriers.6.Forgroundboomapplications, applywith nozzle height no more than4 feet above the ground orcrop canopy.7.For airblast applications, turnoff outward pointingnozzles at rowends and when spraying the outer two rows.To minimize sprayloss overthe top in orchard applications, spraymust be directed intothe canopy.128.For aerial applications, release sprayat the lowest height consistentwith efficacyand flight safety.Ifthe application includes an aquaticbuffer zone, do not release sprayat a height greater than 10 feet above theground or cropcanopy.9.For aerial applications, the sprayboomshould bemounted on theaircraft so asto minimizedrift caused by wing tipvortices.Theminimumpractical boomlength shouldbe used andmust not exceed 75%of the wingspan of 90%ofrotor blade diameter.Useupwind swathdisplacement.1PPE that is established on the basis ofAcute Toxicity of theend-use product must be compared to the active ingredientPPE inthis document.The moreprotective PPE must be placed in theproduct labeling.For guidance on which PPEis considered moreprotective, see PR Notice 93-7.13

### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF

PR EVEN TION , PESTIC ID ES

AN D TOXIC SU BSTAN C ES



### August 20, 2007

MEMORANDUM

SUBJECT: Revised Dim e thoate IRED

TO: Dim e thoate Docket (EPA-HQ-OPP-2005-0084)

This m em o randum constitutes the revised Dim ethoate IRED.

This m em o randum is in two parts. The first part is a February 2, 2007 m em o randum entitled

Response to Public Comments on the Dimethoate Reregistration Eligibility Decision

. The

Response to Com m e nts m e m o randum provides the rationale for the changes from the 2005

Dim e thoate IRED which was posted for public com m e nt. The Dim e thoate IRED required

several risk m itigation m easures, including reductions in application rates and m axim u m

num bers of applications, an increase in retreatm ent intervals for m o st crops, and the addition of

best m anagem ent practices (BMPs) to the labels to reduce spray drift.

Chem inova provided additional com m ents on the m itigation required for handlers on March 30,

2007. W e agreed with those com m ents and have revised the types of respirators required and

added chem ical resistant gloves for all m i xers, loader, applicators, flaggers and other handlers,

with certain exceptions. These changes achieve label sim p lification and provide clear and

protective instructions. The rationale for the changes is included in a 5-page addendum to the

Response to Com m e nt m e m orandum

.

The second part of this m em o randum is an updated label table which includes the m itigation

revisions discussed in the Response to Com m ents m em o randum , as well as the m odifications

EPA proposed (72 FR 8986, February 28, 2007) in certain risk m itigation m e asures based on

com m ents and requests received from users. These m odifications included specifying a

m axim u m seasonal application rate rather than a m axim u m num ber of applications per season,

and increased seasonal rates for peppers and cherries. The label table has also been revised to

correct several errors in the section with requirem ents for reducing spray drift. Specifically, we

have deleted the erroneous requirem e nts on buffer zones for ground boom , chem igation, orchard

and airblast applications to potatoes.

The label table has also been revised to include cottonwood for pulp as a use site. The RED

stated that cottonwood for pulp would be cancelled, based on low perceived benefit in the

### risk/benefit balance required by FIFRA. The Agen cy and the technical registrants have since

learned that use of dim ethoate on cottonwood is considered a highly im portant use by the paper

industry and the U.S. Departm e nt of Agriculture

. The technical registrants, Chem inova and

Drexel, have revised their labels to include this use in registration am endm ents subm itted July 13

and July 23, respectively. The Agency notes that dim ethoate is scheduled for registration review

in 2009, when the occupation risk assessm ent, along with the hum an health and ecological risk

assessm ents, will be reviewed.

For ease of reference, the June 2006 version of the Dim e thoate IRED docum ent is included here

as Attachm e nt 1.

### Addendum to February 2, 2007 Memorandum:

Response to Public Comments on the Dimethoate IRED

Dim ethoate: HED’s Recom m endations f o r Risk Mitigation f o r Handlers

Prepared by: Alan Nielsen on 6/21

### Dimethoate: HED’s Recommendations for Risk Mitigation for Handlers

In HED’s Response to Chem inova’s com m e nts, dated Septem ber 11, 2006, regarding EPA’s

interim reregistration eligibility decision docum ent f o r dim ethoate

HED stated: “HED has no data to establish a short- or interm ediate-term inhalation endpoint for

dim ethoate. Instead, it selected an endpoint based on an om ethoate inhalation study. HED

agrees that dim ethoate is likely to be less toxi c than om ethoate via the inhalation route, although

it has no m eans of quantifying the differential in toxicity. The risk assessm ent acknowledges

that using the inhalation endpoint for om ethoate to assess inhalation risks to dim ethoate is

conservative. In those occupational handler scenarios where inhalation risks are of concern even

with the use of a quarter-face dust/m ist respirator (protection factor of 5), then EPA will take

into consideration the conservative nature of the assessm ent in determ ining whether m o re risk

m itigation (i.e., half-face respirator or engineering controls) is justified.”

Subsequent com m e nts from Chem inova, dated March 30, 2007, indicated concerns about the

risks m itigation to handlers, particularly regarding the requirem ent for a half- or full-face

cartridge or canister respirator. HED agrees with Chem inova that given the conservative nature

of the handler inhalation risk assessm ent, a quarter-face dust/m ist filtering respirator would be

adequate in m any dim ethoate handler scenarios.

HED notes that it believes that residues of om ethoate – the m o re highly toxic degradate of

dim e thoate – likely rem a in on m i xing/loading and application equipm ent. HED has no data to

assess potential handler exposures to om ethoate residues, but believes the concern justifies a

requirem ent for chem ical-resistant gloves and a dust/m ist respirator for dim ethoate handlers who

are not using engineering controls.

HED has reviewed the handler risks to dim e thoate and is proposing the following risk

m itigation:

• 

### W ater-soluble packaging plus baseline attire, chem ical-resistant gloves, and a chem icalresistant apron for all wettable powder form ulations,

• 

### Closed m i xing/loading system s plus baseline attire, chem ical-resistant gloves, and a

chem ical-resistant apron for handlers supporting aerial applications to alfalfa, cotton,

soybeans, corn, safflower, sorghum , and wheat,

• 

### Enclosed cockpits plus baseline attire f o r pilots, and

• 

### Baseline attire plus chem ical-resistant gloves and a quarter-face dust/m ist filtering

respirator for all other m i xers, loaders, applicators, flaggers, and m i xer/loader/

applicators.DIMTHETOATE LABELING FOR KEY SCENARIOSMixing/Loading LiquidsEquipmentCropIRED MitigationRisksHED Proposed MitigationAerial &ChemigationHigh Acreage Crops(0.5 lb ai/A)Closed SystemsAerial:G + 80% R = 32Closed System= 90Chemigation:G + 80% R = 110Closed System= 310Aerial:Closed SystemChemigation:G + 80% R(adequate mitigation)Woody Ornamentals &Conifer Seed Orchardsat 1 lb ai/A)Closed SystemsG + 80% R = 55G, DL, + 80% R = 60Closed System= 150G + 80% R(label simplicity & inhalationendpoint uncertainty)Pears,aCherries (SLN)at 1.0 lb ai/AG + 90% RG + 80% R = 55G, DL, + 80% R = 60Closed System= 150G + 80% R(label simplicity & inhalationendpoint uncertainty)Typical acreage crops< 1.0 lb ai/AG + 90% RG + 80% R =≥110G + 80% R(adequate mitigation)GroundboomHigh Acreage Crops(0.5 lb ai/A)GG = 53G + 80% R = 190G + 80% R(adequate mitigation)Woody Ornamentals &Conifer Seed Orchards(1 lb ai/A)GG = 66G + 80% R = 240G + 80% R(adequate mitigation)Typical acreage crops< 1.0 lb ai/AGG = >100G + 80% R =≥480G + 80% R(label simplicity)AirblastDouglas fir in WA&OR (4.15 lb ai/A)GG = 64G + 80% R = 230G + 80% R(adequate mitigation)≤1.0 lb ai/AGG = >100G + 80% R =≥480G + 80% R(label simplicity)ApplicatorsAerialAllEnclosed cockpitsEng Controls =≥120EnclosedcockpitsGroundboomHigh AcreageBaselineBaseline = 86G + 80% RCropsG + 80% R = 310(adequate mitigation)All other cropsBaselineBaseline =≥110G + 80% RG + 80% R≥390(label simplicity)AirblastDouglas fir inG + 90% RG + 80% R = 39 (PHED)G + 80% RWA&OR(4.3 lb ai/A)G + HG + 80% R = 85(carbaryl)(label simplicity & inhalationendpoint uncertainty &specialty use pattern)Citrus, Pears,aG + 90% RG + 80% R = 80G + 80% RCherries (SLN)(label simplicity & inhalationendpoint uncertainty)Cherries,G + 90% RG + 80% R = 240G + 80% RPecans (0.33 lb(label simplicity)ai/A)FlaggersAerialPears, CherriesEnclosed cab withBaseline =≥49G + 80% R(SLN), WoodyOrnamentals,respiratorG + 80% R > 100(adequate mitigation)Conifer SeedFarms,Christmas TreeFarms(1.0 lb ai/A)All other cropsEnclosed cab withBaseline =≥98G + 80% R(> 1.0 lb ai/ArespiratorG + 80% R > 100(label simplicity)Mixer/Loader/ApplicatorsHigh PressureHandwandWoodyornamentals ,Christmas treefarms, coniferseed orchardsherbaceousornamentals at0.0025 lb ai/galG = 90% RG = 21G + 80% R = 75G + 80% R(label simplicity & inhalationendpoint uncertainty)Low PressureHandwandWoodyornamentals ,Christmas treefarms, andconifer seedorchards at 0.08to 0.01 lb ai/galBaselinePHED:Baseline = 3.9 – 31G = 68 – 540G + 80% R = 260 – 2100ORETF:Baseline = 26 – 210G = 490 – 3900G + 80% R = 950 - 7600G + 80% R(label simplicity)Herbaceousornamentals at0.0025 lb ai/galBaselinePHED:Baseline = 120G = 2200G + 80% R = 8400ORETF:Baseline = 840G = 16,000G + 80% R = 30,000G + 80% R(label simplicity)aPears are listed in the label table at 1.0 lb ai/A, but theproposed mitigation indicates that they will be 0.5 lb ai/A.Revised Dimethoate Label TableLabeling Changes Summary Table(for DCI 2008)In order to be eligible for reregistration, amend all product labels to incorporate the riskmitigation measures outlined in Section IV.The following table describes how language on the labels should be amended.DescriptionAmended Labeling LanguagePlacement on LabelFor all ManufacturingUse Products“Onlyforformulation into an insecticide for the following use(s) [alfalfa,alfalfa for seed, asparagus, beans (excluding cowpeas), broccoli, Brusselssprouts, cauliflower, celery,cherries,Christmas tree farms, coniferseedfarms, cotton, endive, fieldcorn, grass grownfor seed, herbaceousornamentals incommercialnurseries or greenhouses, grapefruit, leaflettuce (except head lettuce), lemons, lentils, kale, melons, mustardgreens, oranges, pears, peas, pecans, peppers, popcorn, potatoes,safflower, sorghum, soybeans, Swiss chard, tangerines, tangelos,tomatoes, turnips, watermelons, wheat, cottonwoodgrown for pulp, andwoodyornamentals in commercial nurseries or greenhouses].”“Not for formulation intowettable powder end use products (EUP),unless the EUP is packaged in water soluble bags.”“Not for formulation intoend-use products intended for use byhomeownersor that permituse at residential sites.”Directions for UseOne of these statementsmaybe addedto a labelto allow reformulationof the product for aspecific use or alladditional usessupported byaformulator or user“This productmaybe usedto formulateproducts for specific use(s) notlisted on theMP label if the formulator, user group,orgrower hascomplied with U.S. EPA submission requirements regarding support ofsuch use(s).”“This productmaybe usedto formulateproducts for anyadditionaluse(s) not listed on the Manufacturing Use Product (MUP) label if theformulator, user group, orgrower has complied with U.S. EPADirections for Use1groupsubmission requirements regarding support of such use(s).”Environmental HazardsStatements Requiredbythe RED andAgencyLabel Policies“Do not discharge effluent containing thisproduct intolakes, streams,ponds, estuaries, oceans, orother watersunless in accordance with therequirementsof a National Pollution Discharge Elimination System(NPDES) permit and the permitting authorityhas been notified inwritingprior todischarge.Do notdischarge effluent containing this product tosewer systems without previouslynotifying the local sewage treatmentplant authority.Forguidance contact your State Water Board orRegional Office of the EPA.”Precautionary StatementsEnd Use Products Intended for Occupational UsePPE RequirementsEstablished by theRED1For Wettable PowderFormulations (wettablepowder productsmustbe packaged in watersoluble bags tobeeligible forreregistration)“Personal Protective Equipment (PPE)”“Somematerials that are chemical-resistant to this product are”(registrant insertscorrect chemical-resistant material).“Ifyou wantmore options, follow the instructions forcategory”[registrant insertsA,B,C,D,E,F,G,or H]“on an EPA chemical-resistancecategoryselectionchart.”“Mixers, loaders, applicators, flaggers, and other handlersmust wear:> Long-sleeved shirt and longpants,> Shoes plussocks,> Chemical-resistant gloves,> a NIOSH-approveddustmist filtering respirator withMSHA/NIOSHapproval number prefix TC-21Cora NIOSH-approved respirator withanyN, R,P,or HE filter, and> Chemical-resistant apron when mixing,loading, cleaning up spills, orequipment.”“See Engineering Controlsfor additional requirements and exceptions.”Instruction toRegistrant:Drop the “N” type filter fromthe respiratorImmediatelyfollowing/belowPrecautionary Statements:Hazards toHumans and DomesticAnimals2statement, if the pesticide product contains, or is usedwith, oil.PPE RequirementsEstablished by theRED1For LiquidFormulations“Personal Protective Equipment (PPE)”“Somematerials that are chemical-resistant to this product are”(registrant insertscorrect chemical-resistant material).“Ifyou wantmore options, follow the instructions forcategory[registrant insertsA,B,C,D,E,F,G,or H]on anEPA chemical-resistancecategoryselectionchart."“Mixers, loaders, applicators, flaggers, and other handlersmust wear:> Long-sleeved shirt and longpants,> Shoes plussocks,> Chemical-resistant gloves,> a NIOSH-approveddustmist filtering respirator withMSHA/NIOSHapproval number prefix TC-21Cora NIOSH-approved respirator withanyN, R,P,or HE filter, and> Chemical-resistant apron when mixing,loading, cleaning up spills, orequipment.”“See Engineering Controlsfor additional requirements and exceptions.”Instruction toRegistrant:Drop the “N” type filter fromthe respiratorstatement, if the pesticide product contains, or is usedwith, oil.Immediatelyfollowing/belowPrecautionary Statements:Hazards toHumans and DomesticAnimalsUser SafetyRequirements“Follow manufacturer'sinstructions forcleaning/maintaining PPE.If nosuch instructions for washables exist,use detergent and hot water.Keepand wash PPE separatelyfromother laundry.”“Discard clothing and other absorbentmaterials that have been drenchedor heavilycontaminated with this product’sconcentrate.Do not reusethem.”Precautionary Statements:Hazards toHumans and DomesticAnimalsimmediatelyfollowing thePPErequirementsEngineering Controls:(Water-Soluble“Engineering controls”Precautionary Statements:Hazards toHumans and DomesticAnimals3Packaging for WettablePowder Formulations)“Pilotsmust use an enclosed cockpitthatmeets the requirements listed inthe Worker Protection Standard (WPS) for agricultural pesticides[40CFR 170.240(d)(6)].Pilotsneed not wear the PPE required in thislabeling for applicators, but mustwearat least a long-sleeve shirt, longpants, shoes, and socks.”“When applicators use enclosedcabs in a manner that meets therequirementslisted in theWorker Protection Standard(WPS) foragricultural pesticides (40 CFR 170.240(d)(5), the handler PPErequirementsmaybe reduced or modifiedas specifiedin the WPS.”(Immediatelyfollowing PPE and UserSafetyRequirements.)“Water-soluble packets, when used correctly, qualifyas a closedmixing/loading systemunder the Worker Protection Standard forAgricultural Pesticides[40CFR 170.240(d)(4)].Mixers and loadersusing water-soluble packetsmust:-- wear the personal protective equipment required in the PPE section ofthis labeling for mixersand loaders,except no respirator is required; and-- be provided and have immediatelyavailable for use in an emergency,such as a broken package, spill, or equipment breakdown:chemicalresistant footwear, and the type of respirator specifiedin the PPE sectionof this label.”Engineering Controls:For LiquidFormulations“Engineering controls”“Mixers and loaders supporting aerial application to alfalfa, cotton,soybeans, corn, safflower, sorghum, and wheatmust use a closed systemthat meets the requirements listed in theWorker Protection Standard(WPS) for agricultural pesticides [40 CFR 170.240(d)(4)]. The systemmust be capable of removing the pesticide fromthe shippingcontainerand transferring it into mixing tanks and/or application equipment.Atanydisconnect point, the systemmust beequipped with a drydisconnector drycoupleshut-off devicethat is warranted bythemanufacturertominimize drippage to nomore than 2ml per disconnect.In addition,mixers and loadersmust:Precautionary Statements:Hazards toHumans and DomesticAnimals(Immediatelyfollowing PPE and UserSafetyRequirements.)4-- wear the personal protective equipment required onthis labeling formixers/loaders, except no respirator is required;– wear protective eyewear, if the systemoperates under pressure; and-- be provided and have immediatelyavailable for use in an emergency,such as a broken package, spill, orequipment breakdown, chemicalresistant footwear and a respirator of the type specified in the PPE sectionof this labeling.”“Pilotsmust use an enclosed cockpitthatmeets the requirements listed inthe Worker Protection Standard (WPS) for agricultural pesticides[40CFR 170.240(d)(6)].Pilotsneed not wear the PPE required in thislabeling for applicators, but mustwearat least a long-sleeve shirt, longpants, shoes, and socks.”“When handlers use closedsystems,or enclosed cabs in a manner thatmeets the requirements listed in the Worker Protection Standard (WPS)for agricultural pesticides (40 CFR 170.240(d)(4-5), the handler PPErequirementsmaybe reduced or modifiedas specifiedin the WPS.”User SafetyRecommendations“USER SAFETY RECOMMENDATIONS”“Users should wash hands before eating, drinking, chewing gum, usingtobacco, or using the toilet.”“Users should remove clothing/PPE immediatelyif pesticide gets inside.Then wash thoroughlyandput onclean clothing.”“Users should remove PPE immediately after handling this product.Wash the outside of glovesbefore removing.As soon as possible, washthoroughly and change intoclean clothing.”Precautionary Statements under:Hazards to Humans and DomesticAnimals immediatelyfollowingEngineering Controls(Must be placed in a box.)Environmental Hazards“Do not apply directlytowater, or to areas where surface water ispresentor to intertidal areas belowthe mean high watermark.Do notcontaminatewater when disposing of equipment washwater or rinsate.”Precautionary Statements immediatelyfollowing the User SafetyRecommendations5“Dimethoate is known to leach throughsoil intoground water undercertain conditions as a result of label use.Use of this chemical in areaswhere soils are permeable, particularlywhere the water table is shallow,mayresult inground-water contamination.”“This productmaycontaminate water throughdrift ofsprayinwind.This product has a high potential for runoff for several daysafterapplication after application.Poorlydraining soils and soils with shallowwater tables aremore prone to produce runoff that contains this product.”“A level, wellmaintained vegetative buffer strip between areas to whichthis product isapplied andsurfacewaterfeatures suchas ponds, streams,and springs will reduce the potential forcontamination of water fromrainfall-runoff.Runoffof this product will be reduced byavoidingapplications when rainfall is forecasted to occur within48hours.”“A vegetative filter strip constructed and maintained in accordancewiththe 2000 Natural Resources Conservation Service publication“Conservation Buffers to Reduce Pesticide Losses”( http://www.nrcs.usda.gov/feature/buffers/) will significantlyreduce thepotential forcontamination of water fromrainfall-runoff.”Restricted-EntryIntervals for productswith directions for usewithin the scope of theWorker ProtectionStandard (WPS) forAgricultural Pesticides(WPS)“Do not enter or allow worker entry into treated areasduring therestricted entry interval (REI).”In the Agricultural Use Requirementsbox“PPE required for earlyentry to treatedareas that is permitted under the6Worker Protection Standardand thatinvolves contact with anything thathas been treated, such as plants, soil, orwater, is:> chemical-resistant gloves made of anywaterproofmaterial,> chemical-resistant footwear plus socks, and> chemical-resistant headgear (if overhead exposure)”Direction for UseAgricultural Use Requirements boxDouble NotificationStatement“Notifyworkers of the application bywarning themorallyand bypostingwarning signs at entrancesto treated area.”Direction for UseAgricultural Use Requirements boxGeneral ApplicationRestrictions“Do not apply this productin a waythat will contact workers or otherpersons, either directlyor through drift.Only protected handlers maybein the area during application.”Place in the Direction for Use directlyabove the Agricultural Use Box.ApplicationRestriction“This productis for useincommercial setting only.Use in residentialsettings is prohibited.”Near the beginningof theDirections forUseEarly Entry PersonalProtective Equipmentfor products withdirections for usewithin the scope of theWorker ProtectionStandard (WPS) forAgricultural Pesticides> coveralls worn over long-sleeve shirt and long pants,Crop-SpecificApplicationRestrictions and REIsThemaximumapplication rate alsomust be statedin termsof the poundsorgallons of formulationLabelsmustbe amended to reflectthe following equipment restrictions,maximumapplication rates, retreatmentinterval, andthe maximumseasonal treatment rates:High Pressure Handwand Equipment:"When applications are madebyhigh pressure handwand equipment,the maximum application rate forall crops and use-patterns is 0.0025 pounds active ingredient per gallon."Alfalfa (grown forseed andforhay),Safflower, and Wheat:Maximumsingle application rate: 0.5 lba.i./A.Maximum total ratepercrop cycle orcutting:0.5 lba.i./A.“TheREI is 48 hours.”Directions for Use associated with theuse directions for the specific crop towhich the restriction pertains7Asparagus, Beans (including fresh, snap, lima, and dry beans) andCotton:Maximumsingle application rate: 0.5 lb a.i./A., 14 dayretreatment interval.Maximum total rateper season:1 lb a.i./A. “TheREI is 48 hours.”Field Corn and Popcorn:Maximumapplication rate: 0.5 lb a.i./A.Maximumtotal rate per year:0.5 lb a.i./A.“The REI is 48 hours.PROHIBITION: Workersare prohibited fromentering the treated area toperformdetasseling tasks for 4 daysin nonarid areas and for15 days inoutdoor areas where the average annualrainfall is less than 25inches peryear.”Broccoli, Brussels Sprouts, and Cauliflower:Maximumapplicationrate: 0.5 lb a.i./A., 7 dayretreatmentinterval.Maximumtotal rate peryear:1.5 lbsa.i./A. “The REI is 48 hours; however, the REI is increasedto 72hours inoutdoor areas where the average annual rainfall is less than25 inches peryear.”Celery:Maximumapplication rate: 0.5lb a.i./A., 7dayretreatmentinterval.Maximumtotal rate per year:1.5 lbs a.i./A.“The REI is 48hours.”Cherries:Maximumapplication rate: 1.33 lbs a.i./A.Maximumtotalrate per year:1.33 lbs a.i./A.“The REI is 10 days; however, the REI isincreased to 14 daysinoutdoor areas where the average annual rainfall isless than 25 inches per year.”Citrus:Maximumapplication rate: 1 lb a.i./A.Maximum total rateperyear:1lb a.i./A.“Do notapplytocitrus in Florida”“Aerialapplicationto citrus is prohibited” “The REI is 10 days; however, the REI is8increased to 14 daysinoutdoor areas where the average annual rainfall isless than 25 inches per year.”Conifer SeedOrchards:Maximumapplication rate: 1 lb a.i./A.Maximumtotal rate per year:1 lb a.i./A.“The REI is 48 hours;however, the REI is increased to 4 daysin outdoor areas where theaverage annual rainfall is less than 25 inches per year.”Special Exception for airblast applications to Douglas Fir SeedOrchards in WA and OR only:Maximum application rate: 4.15lbsa.i./A.Maximum total rateper year: 4.15 lbs a.i./A.“If airblastapplications are applied at a rate greater than 1 lb a.i/A., the REI is 16days;however, the REI is increased to25 daysinoutdoor areas where theaverage annual rainfall is less than 25 inches per year.”Grass Grownfor SeedMaximumapplication rate: 0.5 lba.i./A., 90 dayretreatment interval.Maximumtotal rate per year:1 lb a.i./A.“The REI is 48 hours.”Herbaceous OrnamentalsMaximumapplication rate: 0.25 lb a.i./A.Maximumtotal rate per year:0.25 lba.i./A.“The REI is 48 hours.”KaleMaximumapplication rate: 0.25lb a.i./A., 15dayreapplication interval.Maximumtotal rate per year:0.5 lba.i./A.“The REI is 48 hours.”Leaf lettuce,Swiss Chard,Endive and EscaroleMaximumapplication rate: 0.25lb a.i./A., 7 dayreapplication interval.Maximumtotal rate per year:0.75 lba.i./A.“The REI is 48 hours.”9Lentils, Melon, Honeydew, andPotatoesMaximumapplication rate: 0.5 lba.i./A.,7 dayreapplication interval.Maximumtotal rate per year:1 lb a.i./A.“The REI is 48 hours.”Sorghum, and SoybeansMaximumapplication rate: 0.5 lba.i./A.,7 dayreapplication interval.Maximumtotal application rate per year:1 lb a.i./A.“The REI is 48hours.”Mustard GreensMaximumapplication rate: 0.25lb a.i./A., 9 dayreapplication interval.Maximumtotal rate per year:0.5 lba.i./A.“The REI is 48 hours.”Pears:Maximum application rate: 1 lba.i./A.Maximum totalapplication rate per year:1 lb a.i./A.“The REI 10 days;however, theREI is increased to 14days in outdoor areas where the average annualrainfall is lessthan 25 inches per year.”PecansMaximumapplication rate: 0.33 lb a.i./A.Maximumtotal rate per year:0.33 lba.i./A.“The REI is 48 hours.”PeppersMaximumapplication rate: 0.33lb a.i./A., 7 dayreapplication interval.Maximumtotal rate per year:1.65 lbs a.i./A.“The REI is 48 hours.”Succulent peasMaximumapplication rate: 0.16 lb a.i./A.Maximumtotal rate per year:0.16 lb a.i./A. “The REI is 48 hours.”“Not for use on field peas.”10Note:There are SLN registrations for succulent peas for which the totalseasonal rateis not to exceed 0.5 lbs. a.i./acre.TomatoesMaximumapplication rate: 0.5 lba.i./A.,6 dayreapplication interval.Maximumtotal rate per year:1.0 lba.i./A.“The REI is 48 hours.”TurnipsMaximumapplication rate: 0.25lb a.i./A., 3 dayreapplication interval.Maximumtotal rate per year:1.75 lbs a.i./A.“The REI is 48 hours.”Cottonwood(grown for pulp)Maximumapplication rate: 2 lbs a.i./A.Maximumtotal rate per year: 6lbs a.i./A.“The REI is 14days;however, the REI is increased to 24 daysin outdoor areas where the average annual rainfall is less than 25 inchesper year.”Woody Ornamentals and Christmas TreeNurseries“Maximumapplication rate: 1.0 lb a.i./A., 14 dayreapplication interval.Maximumtotal rate per year:3.0 lbs a.i./A. “When applications aremade byhigh pressure handwand equipment,the maximumapplicationrate for all crops and use-patterns is0.0025 pounds active ingredientpergallon.” “The REI is 10 days;however, the REI is increased to 14 daysinoutdoor areas where the average annualrainfall is less than 25inches peryear.”SprayDriftRequirements for Reducing Spray DriftDo not applyunder circumstanceswhere possible driftto unprotectedpersons or tofood, forage, or otherplantings that might be damaged orDirections for Use11crops thereof rendered unfit for sale, use, or consumption can occur.1.Use the largest droplet size consistentwith acceptable efficacy.Formation ofverysmall dropletsmaybeminimized by appropriatenozzle selection, by orienting nozzles awayfromthe air streamasmuchas possible, and by avoiding excessive sprayboompressure.Forgroundboomand aerial applications, usemediumor coarser spraynozzles according toASAE 572definition for standardnozzles or avolumemeandiameter (VMD) of 300microns or greater for spinningatomizer nozzles.2.Make aerial or ground applications when the windvelocity favors ontarget productdeposition.Applyonlywhen the windspeed is less thanor equal to10mph.For all non-aerial applications, wind speed must bemeasured adjacent to the application site on the upwind side, immediatelyprior to application.3.Do not make aerial or groundapplications intoareas of temperatureinversions.Inversions are characterizedbystable air and increasingtemperatureswith increasing distance above the ground.Mist orfog mayindicate the presenceof an inversion inhumid areas.Where permissiblebylocal regulations, the applicator maydetect the presence of aninversion byproducing smoke andobserving a smoke layer near theground surface.4.Low humidityandhightemperaturesincrease the evaporation rate ofspraydroplets and therefore the likelihood of increased spraydrift.Avoid spraying during conditions oflowhumidityand/or hightemperatures.5.All aerial and ground application equipmentmust be properlymaintained and calibrated using appropriate carriers.6.Forgroundboomapplications, applywith nozzle height no more than4 feet above the ground orcrop canopy.7.For airblast applications, turnoff outward pointingnozzles at rowends and when spraying the outer two rows.To minimize sprayloss over12the top in orchard applications, spraymust be directed intothe canopy.8.For aerial applications, release sprayat the lowest height consistentwith efficacyand flight safety.Ifthe application includes an aquaticbuffer zone, do not release sprayat a height greater than 10 feet above theground or cropcanopy.9.For aerial applications, the sprayboomshould bemounted on theaircraft so asto minimizedrift caused by wing tipvortices.Theminimumpractical boomlength shouldbe used andmust not exceed 75%of the wingspan of 90%ofrotor blade diameter.Useupwind swathdisplacement.1PPE that is established on the basis ofAcute Toxicity of theend-use product must be compared to the active ingredientPPE inthis document.The moreprotective PPE must be placed in theproduct labeling.For guidance on which PPEis considered moreprotective, see PR Notice 93-7.13

# Attachment 1

Signed Dimethoate IRED

June 2006

### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY



### WASHINGTON D.C., 20460

OFFICE OF

PR EVEN TION , PESTIC ID ES AN D TOXIC

SU BSTAN C ES



### MEMORANDUM

DATE: July 31, 2006

SUBJECT: Finalization of Interim Reregistration Eligibility Decisions (IREDs) and Interim

Tolerance Reassessm ent and Risk Managem e nt Decisions (TREDs) for the

Organophosphate Pesticides, and Com p letion of the Tolerance Reassessm ent and

Reregistration Eligibility Process for the Organophosphate Pesticides

FROM: Debra Edwards, Director

Special Review and Reregistration Division

Office of Pesticide Program s

TO: Jim Jones, Director

Office of Pesticide Program s

As you know, EPA has com p leted its assessm ent of the cum u lative risks from the

organophosphate (OP) class of pesticides as required by the Food Quality Protection Act of

1996. In addition, the individual OPs have also b een subject to review through the individualchem ical review process. The Agency’s review of individual OPs has resulted in the issuance of

Interim Reregistration Eligibility Decisions (IREDs) f o r 22 OPs, interim Tolerance

Reassessm ent and Risk Managem e nt Decisions (TREDs) for 8 OPs, and a Reregistration

Eligibility Decision (RED) f o r one OP, m alathion. 1 

### These 31 OPs are listed in Appendix A.

EPA has concluded, after com p leting its assessm ent of the cum u lative risks associated

with exposures to all of the OPs, that:

(1) the pesticides covered by the IREDs that were pending the results of the OP

cum u lative assessm ent (listed in Attachm ent A) are indeed eligible f o r reregistration; and

1 Malathion is included in the OP cum u lative assessm ent. However, the Agency has issued a RED for m a lathion,

rather than an IRED, because the decision was signed on the sam e day as the com p letion of the OP cum u lative

assessm ent.



### Page 1 of 3

### (2) the pesticide tolerances covered by the IREDs and TREDs that were pending the

results of the OP cum u lative assessm ent (listed in Attachm ent A) m eet the safety standard under

Section 408(b)(2) of the FFDCA.

Thus, with regard to the OPs, EPA has f u lf illed its obligations as to FFDCA tolerance

reassessm ent and FIFRA reregistration, other than product-specific reregistration.

The Special Review and Reregistration Divisi on will be issuing data call-in notices f o r

confirm atory data on two OPs, m ethidathion and phorate, for the reasons described in detail in

the OP cum u lative assessm ent. The specif i c studies that will be required are:

− 28-day repeated-dose toxicity study with m ethidathion oxon; and

− Drinking water m onitoring study for phorate, phorate sulfoxide, and phorate sulfone

in both source water (at the intake) and treated water for five com m unity water

system s in Palm Beach County, Florida and two near Lake Okechobee, Florida.

The cum u lative risk assessm ent and supporting docum ents are available on the Agency’s website

at www.epa.gov/pesticides/cum ulative and in the docket (EPA-HQ-OPP-2006-0618).

Page 2 of 3

### Attachment A:

Organophosphates included in the OP Cum u lative Assessm ent

Chemical Decision Document Status

Acephate IRED IRED com p leted 9/2001

Azinphos-m ethy l (AZM) IRED IRED com p leted 10/2001

Bensulide IRED IRED com p leted 9/2000

Cadusafos TRED TRED com p leted 9/2000

Chlorethoxy phos TRED TRED com p leted 9/2000

Chlorpy r ifos IRED IRED com p leted 9/2001

Coum aphos TRED TRED com p leted 2/2000

DDVP (Dichlorvos) IRED IRED com p leted 6/2006

Diazinon IRED IRED com p leted 7/2002

Dicrotophos IRED IRED com p leted 4/2002

Dim e thoate IRED IRED com p leted 6/2006

Disulfoton IRED IRED com p leted 3/2002

Ethoprop IRED IRED com p leted 9/2001

IRED addendum com p leted 2/2006

Fenitrothion TRED TRED com p leted 10/2000

Malathion RED RED com p leted 8/2006

Metham idophos IRED IRED com p leted 4/2002

Methidathion IRED IRED com p leted 4/2002

Methy l Parathion IRED IRED com p leted 5/2003

Naled IRED IRED com p leted 1/2002

Oxy d em eton-m e thy l IRED IRED com p leted 8/2002

Phorate IRED IRED com p leted 3/2001

Phosalone TRED TRED com p leted 1/2001

Phosm e t IRED IRED com p leted 10/2001

Phostebupirim TRED TRED com p leted 12/2000

Pirim iphos-m ethy l IRED IRED com p leted 6/2001

Profenofos IRED IRED com p leted 9/2000

Propetam phos IRED IRED com p leted 12/2000

Terbufos IRED IRED com p leted 9/2001

Tetrachlorvinphos TRED TRED com p leted 12/2002

Tribufos IRED IRED com p leted 12/2000

Trichlorfon TRED TRED com p leted 9/2001



### Page 3 of 3

# Interim Reregistration

Eligibility Decision for

Dimethoate

J une 1 2, 2006

# Interim Reregistration Eligibility Decision

for

Dimethoate

List [B]

Case No. 0088

# Tabl e of Cont ents

Dimethoate Interim Reregistration Eligibility Decision Team

...................................... i

Glossary of Terms and Abbreviations

............................................................................ ii

II. Chemical Overview

............................................................................................... 2

A. Regulatory History

................................................................................................ 2

B. Chemical Identification

........................................................................................ 3

C. Use Profile

.......................................................................................................... 3

III. Summary of Dimetho a te Risk Assessmen ts

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

A. Human Health Risk Assessment

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

1. Toxicity of Dimethoate

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

2. Dietary Exposure and Risk from Food and Water

........................................ 9

3. Residential and Other No n-occupational Risk

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

4. Aggregate Exposure and Risk

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

5. Occupation al Exposure and Risk

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

6. Human Incident Data

..................................................................................... 18

B. Environmental Risk Assessment

....................................................................... 18

1. Environmental Exposure

............................................................................... 18

2. Environmental Effects (Haz ard)

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

3. Ecological Risk Estimation

............................................................................. 23

4. Ecological Incidents

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

5. Risk Characteriz a tion

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

6. Endangered Species Consideratio n s

............................................................. 30

IV. Interim Ris k Management, Reregis tration, and Tolerance Reassessment

Decision

....................................................................................................................... ..... 30

A. Determination of Rere gistration Eligib ility

.................................................. 30

B. Public Comments and Responses

...................................................................... 31

C. Regulatory Position

............................................................................................. 31

1. Food Quality Protection Act Findings

.......................................................... 31

2. Interim Tolerance Summary

......................................................................... 33

D. Regulatory Rationale

.......................................................................................... 37

1. Significan ce of Use

.......................................................................................... 43

2. Spray Drift

....................................................................................................... 44

3. Endangered Species Consideratio n s

............................................................. 44

V. What Registrants Need to Do

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

A. Manufactu ring Use Products

............................................................................. 47

1. Additional Generic Data Requirements

........................................................ 47

B. End-Use Products

................................................................................................ 48

1. Additional Product-Speci fic Data Requirements

......................................... 48

2. Labeling for End-Use Products

..................................................................... 48

Labeling Changes Summary Table

........................................................................... 49

## Dimethoate Interim Reregistration Eligibility Decision Team

Office o f Pesticide Prog rams:

Biological and Econom i c Analysis Assessm ent

Nikhil Ma llam palli

Elisa Rim

Environm ental Fate and Effects Risk Assessm ent

R. David Jones

Thom as Steeger

Health Effects Risk Assessm ent

Byong-Han (Paul) Chin

David Hrdy

Christin a Ja r v is

Diana Lock e

Anna Lowit

Alan Nielsen

Registration Support

Dan Kenny

Anne Hanger

Risk Managem e nt

Stephanie P l umm e r

Laura Parsons

i

## Glossary of Terms and Abbreviations

AGDCI Agricultural Data Call-In

ai Active Ing r e d ient

aPAD Acute Population Adjusted Dose

AR Anticipa t ed Residue

BCF Bioconcentration Factor

CFR Code of Federal Regulations

cPAD Chronic Population Adjusted Dose

CSF Confidential Statem ent of For m ula

CSFII USDA Continuing Survey s for Food Intake by Individuals

DCI Data Call-In

DEEM Dietary Exposure Evaluation Model

EC Em ulsifiable Concentrate Form ulation

EDWC Estim ated Drinking W a ter Concentration

EEC Estim ated Environm ental Concentration

EPA Environm ental Protection Agency

EUP End-Use Product

FCID Food Commodity Intake Database

FDA Food and Drug Adm i nistration

FIFRA Federal Inse ctic ide, Fun g icide, and Rodenticid e Act

FFDCA Federal Food, Drug, and Cos m etic Act

FQPA Food Quality Protection Act

FOB Functiona l Observation Battery

G Granular Form ulation

GENEEC Tier I Surface W a ter Computer Mod e l

GLN Guideline N u m b er

HAFT Highest Average Field Trial

IR Index Reservoir

LC 50 

### Median Lethal Concentration. A statistically derived concentration

of a substance that can be expected to cause death in 50% of test

anim als. It is usually expresse d as the weight of substance per

weight or volum e of water, air or feed, e.g., m g /l, m g /kg or ppm

. LD 50 

### Median Lethal Dose. A statisti cally derived single dose that can be

expected to cause death in 50% of th e tes t anim als when

adm i nistered by the route indicated (o ral, derm al, inhalation). It is

expressed as a weight of substan ce per unit weight of anim al, e .g., mg/kg.

LOC Level of Concern

LOD Lim it of Det ection

LOAEL Lowest Observed Adverse Effect Level

MATC Maxim u m Acceptable Toxicant Co ncentration

Φ g/g Microgram s Per Gram

Φ g/L Microg ram s Per Lite r mg/kg/day Milligram Per Kilogram Per Day

mg/L Milligr a m s Per Lite r

ii

### MOE Margin of Exposure

MRID Master Reco rd Identification (num ber). EPA' s system of recording

and tra c king studies sub m itted.

MUP Manufacturing-Use Product

NA Not Applica b le

NAWQA USGS National W a ter Quality Assessm e nt

NPDES National Po llutan t Disch a rge Elim ination Syste m

NR Not Required

NOAE L No Observed Adverse Effect Level

OP Organophosphate

OPP EPA Office of Pesticide Program s

OPPTS EPA Office of Preventio n, Pe sticides and Toxic S ubstances

PAD Population Adjusted Dose

PCA Percent Cro p Area

PDP USDA Pesticide Data P r ogram

PHED Pesticide Handler' s Exposure Data

PHI Preharvest Interval

ppb Parts Per Billion

PPE Personal Protective Equip m ent

ppm Parts Per Million

PRZM/EXAMS Tier II Surface W a ter Computer Model

Q 1 

### * The Carcinogenic Potential of a Compound, Quantified by the

EPA' s Canc er Risk Mod e l

RAC Raw Agriculture Commodity

RED Reregis t ra tion Eligib ility Decision

REI Restricted E n try In terv al

RfD Reference Dose

RQ Risk Quotient

SCI-GROW Tier I Ground W a ter Computer Model

SAP Science Advisory Panel

SF Safety Factor

SLC Single Layer Clothing

SLN Special Local Need (Registrat ions Under Section 24(c) of FIFRA)

TAF Toxicity Adjustm e nt Factor

TCPSA 2,3,3-trichloroprop-2-ene sulfoni c acid (nitrapyrin Metabolite)

TGAI Technical Grade Active Ingredient

TRR Total Radio activ e Resid u e

USDA United States Departm e nt of Agriculture

USGS United States Geological Survey

UF Uncerta inty Factor

UV Ultrav iole t

WPS Worker Protection S t andard

iii

### I. Introductio n

The Federal Insecticide, Fungicide, a nd Rodenticide Act (FIF RA) was a m ended

in 1988 to accelerate the rereg i stratio n of produc ts with active ingred ients registered prior

to Novem b e r 1, 1984. The am ended Act calls for the developm ent and subm ission of

data to support the reregistra tion of an active ingredient, as well as a review of all

subm itted data by th e U.S. Environmental P r otec tion Agency (here a f t er r e f e rred to a s EPA or the Agency). Reregistration involves a thorough review of the scientific database

underlying a pesticide' s registra tion. The purpose of the Agency' s review is to reassess

the poten tia l risks a r is ing f r om the currently r e gis t ered us es of the pes tic id e, to determ ine

the need for additional data on health and environm ental effec t s, and to determ ine

whether or n o t the pesticide m eets the "no unreaso n able advers e effects" criteria of

FIFRA.

On August 3, 1996, the Food Quality Protection A c t of 1996 (FQPA) was signed

into law. This Act am ends FIFRA to requir e re as sessm ent of all tole rance s in ef f e ct o n the day before it was enacted by August 2006. EPA decided that, for those chem icals

that hav e tolerances and are undergoing rere g i stration, to leran c e reassess m e nt will be

accom p lished through th e reregistration process. FQPA also am ended the Federal Foo d,

Drug, and Cosm etic Act (FFDCA) to require a safety finding in tolerance reassessm ent

based on factors that include an assessm e nt of cumulative effects of chemicals with a

common m e chanism of t oxicity. The reason for consideration of other sub s tances is th at

the possib i lity exis ts th at low-level exposures to multiple chem icals that cause a com m on

toxic effect lead to the sam e adverse health effect as would a hi gh level of exposure to

any one of the other substances individually.

As m e ntioned above, FQPA requires EPA to consider "available inform ation"

concern i ng the cum u lative effects of a part icular pesticide' s residues and "other

substances that have a comm on m e c h anism of toxicity" when consider ing whether to

establish, m odify, or revoke a tolerance. Dim e thoate is a mem b er of the organophosphate

(OP) class of pesticides. The OPs, as a group, have been determ ined to share a common

m echanism of toxicity. The Agency has co m p leted a rev i sed cum u lative r i sk asse ssm ent

for OPs (USEPA, 2002), which can be found on the Agency’s website

http://www.epa.gov/pesticides/cum ulative/rra-op/

. The Agency intend s to issue th e f i n a l

tolerance reassessm ent reregistration decisi ons for dim e thoate and the OPs in August

2006. The Agency m a y need to pursue further risk m itigatio n for dim e thoate to address

any risks ide n tif ied in the cum u lative assessm ent f o r the OPs.

This document presents EPA’s revised hum an he alth and ecological risk assessm ents

and its p r ogr ess toward toleran ce re a ssessm ent, and the in ter im reregis t ra tion eligibility

decision for dim e thoate. The document consists of six s ections: section I contains the

regulatory fram e work for reregistration/tole rance reassessm e n t; section II provides a

profile of the use and usage of the c h em ical; sec tion I II g i ve s an overview of the revised

hum a n health and environm ental effects risk assessm ents based on data, public

comments, and other inform ation received in resp onse to th e p r elim inary risk

assessm ents, section IV presents the Agen cy’s re regis t ra tion elig ibility, toleran ce

1

### reassessm ent, and risk managem e nt decisi ons; section V summ arizes label changes

necessa ry to im plem ent the risk m itig ation m easures outlined in Section I V ; and section

VI provides inform ation on how to access re lated docum ents. Finally, the Appendices

list related and supporting docum ents and Data Call-In (DCI) inform ation. The revised

risk assessm ent docum ents and related addenda are not inclu d ed in th is d o cum e nt, but are

available on the Agency’s web page http:// www.epa.gov/pesticides

, and in the Public

Docket under docket number EPA-HQ-OPP-2005-0084.

II. Chemical Overview

A. Regulatory Histo ry

Di m e thoate is a system ic organophosphate in secticide used on a large variety of

field grown agricultural crops, tr ee crops, and ornam e ntals. It was f i rs t r e gistered in the

United States in 1962. All non-agricultural uses, including resi dential uses, were

cancelled in 2000. In ad dition, s e ven crops that were iden tified as sign ificant dietary risk

contributors (apples, broccoli r aab, cabbage, collards, grapes, head lettuce, and spinach),

along with f our crops for which there were no field trial data to support tolerances

(fennel, lesp edeza, tom a tillo, a nd trefoil) were cancelled in 2 005 (Federal Register

Notice/Vol. 70, No. 138/Wednesda y, July 20, 2005/Notices/41714). None of these crops

were consid ered in the current risk assessm ents

. Di m e thoate is classified as a general use

pesticide, and is applied using ground and aerial equipm ent. A bout 1.8 million pounds of

active ingredient are used annually, with the largest use occurring on al falfa. Use on four

m a jor crops - alfalfa, wheat, cotton, and co rn - account for more than 64% of total

dim e thoate use.

There are currently 40 products containi ng dim e thoate registered under Section 3

of the Federal Insecticide, F ungicide and Rodenticide Act (F IFRA). There are also 39

active Special Local Need registrations regist ered under Section 24(c) of FIFRA. Thi s

Inter i m Reregistr a tion Eligibil ity Decision docum ent evaluates risks from all currently

registered uses.

EPA released the rev i sed hum a n health a nd eco lo gical risk as sessm ents for a th ird

round of public comm e n ts on September 6, 2005. Prior to this, the last public com m e nt

period had o ccurred in 1 999, at which tim e the registrant sub m itted a developm ental

neurotoxicity study. The results of that st udy necessitated major revisions to the risk

assessm ents.

2

### B. Chemical I d entificatio n

Chemical S t ructure:

Common Name: Di m e thoate

Chemical N a me: O,O -di m ethyl S -( N -m ethylcarbam o ylm e thyl)

phosphorodithioate

Chemical F a mily : Organophosphate

Empirica l Formula: C 5 

### H 12 

### NO 3 

### PS 2



### CAS Registry Number: 60-51-5

Case Number: 0088

OPP Chemical Code: 035001

Molecula r w e ight: 229.3

Trade Names: Digon, Duragon, Rebelate, Dim a te

Basic Manufacturers: Che m inova, BASF Corporati on, Drexel Chem ical Co.

Dim e thoate is a white cr ystalline solid with a m e rcaptan odor and a m e lting point

of 45-48 o 

### C. It is soluble in water at 25 g/L at 21 o 

### C, is highly soluble in chloroform

,

m e thylene chlorid e , ben zene, to luen e, alcoho ls , esters, and ketones, and is only slightly

soluble in xylenes, carbon tetrachloride, and aliphatic hydrocarbons. Dim e thoate is also

stable in aqueous solutions at pH 2- 7, but hydrolyzes in alkaline m e dia.

The m a jor toxic degradate of dim e thoate is om e t hoate ( O,O -dim ethyl S -( N

m e thylcarbamoyl m e thyl) phosphorothioate). Omethoate is regist ered as an active

ingred ient in terna tionally, but not in the United States.

C. Use Profile

The f o llowing is inf o rmation on the curren tly registered uses of di m e thoate,

including an overview of use sites and applic ation m e thods. A detail ed table on the uses

of di m e thoate eligible for reregistration is contained in Appendix A.

3

### Type of Pesticide: General us e system ic ins ecticide/acaricide

Summary o f Use: Used for control of a variety of insect pests on a num b er of

fruit, vegetable, grain, and fiel d crops, as well as ornam e ntals

and non-cropland adjacent to agricultural fields

Food uses : Registered for use on the following crops/sites:

Alfalfa, asparagus, beans (excluding cowpeas), broccoli, Brussels sp routs, caulif lower,

celery, cherries, Chinese cabbage, cotton, endi ve, field corn, grapefruit, leaf lettuce,

lem ons, lentils, ka le, m e lons, m u stard greens, ora nges, pears, peas, pecan s

, peppers, popcorn, potatoes, safflower, sorghum, soyb eans, Swiss chard, tangerines, tangelos,

tom a toes, turnips, wate r m elons, wheat

Non-food uses :

Alfalfa for seed, forestry applications, gr ass for seed, non-crop land adjacent to

vineyards, nursery stock (inc luding conifer seed f a rm uses), ornam e ntals (various)

Uses not supported for reregistration:

Food crops: kohlrabi, lupine, sainfoin, triticale

Non-agricultural uses – cottonwoods grown for pul p, outdoor household dom e stic

dwelling (ornam entals and shr ubs), recreational areas, outdoor

commercial/institutional/industrial prem ises, out door refuse/solid waste, phragm ites reed

beds, and sewage treatment system s

Target Pests: Aphids, citrus thrips, gr asshoppers, leafm i ners, m ites,

whitef lies, b eetles, weev ils, m i dges, scale, fruitw orm s

, moths, leafrollers, rootworm s, m ealybugs, leafhoppers,

lygus bugs, and m a ggots

Formulation Types: Em ulsifiable concentrate and wettable powder end-use

products

Method and Rates of Application:

Application Methods: Applied prim arily as a foliar spray, although soil

and bark drench uses are registered

Application Equipm ent: Aircraft, groundboom

, airblast, chem igation,

backpack sprayer, low pressure handwand, and soil

drench equ i pm ent, sprin k ler can and paint b r ush

4

### Application Rates: Currently labeled use rates vary from a m i ni m u m of

0.16 lbs a.i./acre to a m a xim u m of 33.2 lbs. a.i./acre

per application. Many labels do not specify

num b ers of applications, but typically 1 to 6

applications per year are m a de. For most crops, the

m a xi m u m a pplication rate is 0.5 lbs a.i./acre with

typically 3 applications m a de per year. Note that

Douglas fir seed orchards in Oregon and

Washington, pinyon pine, and cottonwood

application rates range from 8.0 lbs a.i./acre to 33.2

lb a.i. /acr e with one application per year.

Application Tim i ng: Bearing, early spring, foliar, non-bearing

nurserystock, nurserystock, petal f a ll, petal f a ll

through foliar, postharvest, postplant, preharvest,

seed, seed crop, when needed

Use Classification: General

D. Estimated Usage of Pesticide

The estim ate for total dom e stic us e (annual average) of dim e thoate is

approxim a tely 1.8 m illio n pounds of activ e ingredie nt, with the m a jority of use occurring

on the following crops: wheat, alfalfa, cotton, and corn.

III. Summary o f Dimethoa te Risk Assessments

The purpose of this summ ary is to assist the read er by iden tif ying the key features

and findings of these risk assessm ents, a nd to help the reader better understand the

conclus i ons reached in the assessm ents. The hu m a n health and ecological risk

assessm ents for m the basis of interim regulat ory decisions for dim e thoate. W h ile the

risk assessm ents and related addenda are not in clu d ed in th is d o cum e nt, they are av aila ble

from the OPP Public Docket EPA- HQ-OPP-2005-0084 and m a y be accessed on the

inte rnet a t http://www.regulations.gov

.

EPA released the revised risk assess m e nts for dim e thoate for a third public

comment phase on September 6, 2005. In response to comm e n ts received, the risk

assessm ents were further updated and refined.

A. Human Health Risk Assessment

The Agency prepared a revised hum an health risk assessm ent, “Dim ethoate: The

Post-SAP HED Chapter of the Rereg i strati on Eligibility Decision Document (RED)”

written by Diana Locke, et al (January 31, 2006), which addresses toxicology data and

comments subm itted du ring th e m o st recent public comm ent period for dim e thoate. In

5

### addition, the drinking water assessm ent was re vised to include all the uses that are

supported by the technical registrant with fully defined use patterns.

1. Toxicity of Dimethoate

(For a com p lete discussion, see section 3.0 of the hum a n health risk assessm e nt.)

Table 1. Acute Toxicity of Di m e thoate

Guideline No

. Stud y T y pe MRI D N o

. Results T oxi ci t y

Ca te gor y

87 0. 1 1 0 0 Acut e O r al - R a t 00 1 6 4 2 19 LD 50 = 358 mg /kg

males) , 41 4 mg /kg

(fem a les) II

8 7 0

. 12 00 A c u t e D e r m al

- Rabb it 0 016 422 0 LD 50 = > 2

. 0 g/ kg II I

87 0. 2 5 0 0 Acute De rm al Ir ritation

­ Rab b it 00 1 6 4 2 21 Not a

de rm al i rri t a nt IV

87 0. 2 6 0 0 Sk in Sen s itizatio n - Gu in ea Pig 2 549 24 No t a sk in sen s itizer N/A

87 0. 6 1 0 0 Acu t e Delayed Neu r o t ox icity

- H e n 4 288 440 1 No clinical signs of acute

del a y e d neu r ot oxi ci t y

an d no co m p ou ndrel a t e d hi st ol o g i cal

changes in nerve tissue

. N/A

* Accepta ble a c ute and prim a r y eye irritation st udies ha ve not bee n s u bm itted, and a r e t h erefore conside r ed

dat a ga ps at t h i s t i m e

.



### As with other organophosphate (OP) pestic ides, the critical ef fect of dim e t hoate

for various exposure durations is inh i bition of cho lines terase (ChE) in the brain or b l o od

com p art m ent. ChE inhibition is the most sensitive endpoint in num erous studies with

adult and juvenile animals following oral, de rmal, or inhalation expos ures of dim e thoate

or om ethoate (the p r im ary m e tabolite). ChE inhibition was the m o st sensitiv e endpoint in

an inhalation study with om ethoate.

Oral studies evaluating the subchronic, chronic, developm ental, and reproductive

toxicity in laboratory anim als are available for both dim e thoate and om ethoate.

Developm ental neurotoxicity (DNT), com p ar ative choline s te ra se, and spec ial cros s fostering s t u d ies are available for d i m e thoa te. These studies show that brain ChE

inhibition occurs at doses sim ilar to or lowe r than those causing ChE inhibition in blood.

Furtherm ore, these studies show that brain Ch E inhibition occurs at doses sim ilar to those

associated w ith increases in pup m o rtal ity observed in the D N T study. The FIFRA

Scientific Advisory Pan e l m e t on Novem b er 30 and Decem ber 1, 2004 to deliberate o n

the in terp retation of the data f r om these st udies and concluded that brain ChE inhibition

is an appropriate endpoint to use for risk assessm ent.

The risk assessm ent for dim e thoate is based on benchm ark dose values, rather

than No Observed Adverse Effect Level ( NOAEL) and Lowest Observed Adverse Effect

Level (LOAEL) values. The Agency used this m e thod because NOAELs and LOAELs

do not necessarily reflect the relation sh ip between dose and response for a given

chem ical, but instead are reflective of dose sele ction. In order to evaluate the appropriate

6

### point of departure (PoD) for ChE inhibi tion and pup m o rtality, EPA perform e d a

benchm ark dose (BMD) analysis. ChE inhibi tion data from the following dim e thoate

studies in rats were analyzed: the comp arative C h E study, the reproductive toxicity

studies, and the 28-day s ubchronic toxicity study.

The dose at which 10% ChE inhibiti on would be expected to occur (BMD 10 

### ) and

the lower 95 % conf idenc e inte rvals ( B MDL 10 

### ) were es tim ated by f itting the ChE data to

an exponential dose-response m odel, using ge neralized nonlinear l east squares. The

BMD 10 

### was selected because it is generally at o r near th e lim it of sensitivity f o r

discern i ng a statistically significan t d ecrease in C h E activity across the blood and brain

com p art m ents and is a response leve l close to the background ChE level.

The dose and endpoint f o r establishing the acute reference dose (aRfD) for all

population subgroups is the BMDL 10 

### = 1.3 m g /kg for postnatal day 11 (P ND 11) in

fe m a le pups. The endpoint of concern (ChE i nhibition ) was s een after a single oral do se, and thus is appropriate f o r the genera l population and duration of concern. An

uncertainty f actor (UF) of 100 was applied to acco unt for inter-species extrapolation

(10X) and intra-species variab ility (10X), resulting in an aRfD of 0.013 mg/kg. The dose

and endpoin t (ChE inhib ition ) for establish i ng th e chronic ref e rence do se (cRfD) for all

population subgroups is the BMDL 10 

### of 0.22 m g / kg/day from a chronic feeding study on

rats, which is the endpoint that was used in the dietary risk assessm ent for the OP

cum u lative assessm ent. Again, an UF of 100 wa s applied, resulting in a cRfD of 0.0022

mg/kg/day. The BMDL 10 

### and other toxicity endpoints ar e outlined in Table 2 below.

FQPA Safety Factor

The FQPA Saf e ty Facto r (as m a ndated by the Fo od Quality P r otec tion Ac t of

1996) is intended to provide up to an additional 10-fold safety factor (10X ), to protect for

special sensitivity in infants and children to pesticide resi dues in food and drinking water

or from residential exposures, or to com p ensa te f o r an incom p lete d a taba se. In the ca se

of di m e thoate, the Agency has concluded th at the FQPA Safety Factor should be

rem oved based on the lac k of pre- an d/or postn atal suscep tib ility resu lting f o llowing

exposure to dim e thoate/om e thoate, the lack of residual un certainties for pre- and/or

postnatal toxicity, and the fact that the di m e thoate food and drinking water assessm e n ts

are not expected to underestim a te exposure.

Cancer Classification

The Agency’s Cancer Peer Review Comm itt ee (C ARC) classified dim e thoate as a

Group C carcinogen (possible hum an carcinogen; final docum ent dated 8/29/91) based on

equivocal hemolym phoreticular tum o rs in m a le B6C3F1 m i ce, the com p ound-related (no

dose respon se) weak effect of com b i n ed spleen (hem angioma and hem a ngiosarcom a),

skin (hem angiosarcom a ), and lym ph (angiom a and angiosarcom a ) tum o rs in m a le W i star

rats, and po s itiv e m u tagenic ac tivity associa t ed w ith dim e thoa te. For th e p u rposes of risk

assessm ent and characterization for dim e thoate, the PAD approach, and not a Q 1 

### *

approach, w a s considered m o re appropriate fo r q u antif ica tion of potentia l hum a n risk f o r

7

### the following reasons: as stated above, the m ouse carcinogenicity study showed

equivocal hemolym phoreticular tum o rs, a nd the rat carcinogeni city study showed a

com pound-r e lated, weak effect of co mbined spleen (hem angiom a and

hem a ngiosarcom a ), skin (hem angiosarcom a ), and lym ph (angiom a and angiosarcom a )

tum o rs, but there was no dose response. In a ddition, the chronic Reference Dose (RfD) is

considered protective enough of any potential cancer risk since the NOAEL fro m wh ich

it is derived (0.05 m g /kg / d) is at least an order of m a gnit ude lower than the NOAELs or

LOAELs de rived from the system ic effects seen in the rat and m ouse carcinogenicity

studies. On June 25, 1992, the FIFRA Scientif ic Advisory Panel (SAP) concurred with

the Agency' s class i fication of di m e thoate as Group C carcinogen.

Table 2. Toxicity Endpoints for Hum a n H ealth Risk Assessm e nt for Dim e thoate

Expos ure Sce n ario Dose

, Unce rtainty

Factor, a n d

Safety Factor Effect St udy

Acute Dietary (all

p opu latio n s ) BMDL 10 = 1. 3

m g / kg

U F = 100

FQP A SF = 1 B r ai n C h E i n hi bi t i on i n

PN D1 1 fem a les (BM D 10 = 1.5

m g / kg) Co m p arativ e Ch EI stud y in rats.

MRI D 4 552 970 2

Acut e R f D = Acut e P A D = 0. 01 3 mg/k g

Chronic Dietary (all

p opu latio n s ) BMDL 10 =

0. 22 m g / kg/ d

U F = 100

FQP A SF = 1 B r ai n C h E i n hi bi t i on i n

fem a les (BM D 10 = 0.25

m g / kg/ d). 2- Year ch r oni c fee d i n g st u d y i n

rats.

MRI D 0 016 417 7

Chr o nic Rf D = Chr o nic PA D = 0. 0 0 2 2 mg /kg/d

Sh ort

- ( 1

- 3 0 da y s )

an d In term ed iateterm (1-6 m onths)

Occup a tion a l

Derm al BMDL 10 =

18 .6 7 m g / kg/ d

U F = 100 B r ai n C h E i n hi bi t i on i n m a l e s

at

28 day s (B M D 10 = 28.70

m g / kg/ d). 28-Day re peated dos e derm al

to x i city in rats.

MRI D 4 499 910 1

Shor t - and I n termediate -te r m Occu pational Der m al LOC = 100

Sh ort

- ( 1

- 3 0 da y s )

an d In term ed iateterm (1-6 m onths)

Occup a tion a l

In hal a t i on BMCL 10 =

0. 38 m g /m 3

(ap p r o x 0. 10

m g / kg/ d)

U F = 100 B r ai n C h E i n hi bi t i on i n m a l e s

at

15 day s (B M C 10 = 0. 51

mg / m 3 ). Om ethoate 21-day re peated

d o s e inh a latio n stud y in rats.

MRI D 4 635 860 1.

(See discussion of relative

t oxi ci t y of om et hoat e i n Sect

. II I.A

. 2 b e lo w.)

Shor t - and I n termediate -te r m Occu pational Inhal a tion LOC = 100

C a ncer C l assi fi cat i on: Gr o u p C or Po ssi bl e H u m a n C a rci n o g e n

UF = Uncer tain t y F actor (10X fo r int e r-s pec i es e x trapol ation and 10X for intr a-s p eci es var i at ion)

FQPA SF = Food Quality Protection Act Saf e ty Factor

RfD = Referen c e Dose

PAD = Population Adjusted Dos e (RfD ÷ FQPA SF)

LOC = Lev e l o f Concern



### 8

### 2. Dietary Exposure and Ri sk from Food and Water

Acute and chronic prob abilis tic dietary risk asses s m e nts were conducted u s ing

DEEM-FCIDTM, Version 2.02, which incorpor ates consum ption data from USDA’s

CSFII, 1994-1996 and 1998, as well as m onitoring data from PDP and the FDA

Surveillance Monitoring Program , estim ated percent crop treated inform ation, and

processing/cooking factors, where applicable

. Since the tolerance expression includes

both dim e thoate and om ethoate, the residues of parent and its m e ta bolite were summ e d

for use in th e dietary ris k assessm ent. Fu rthermore, since it was determ ined that

om ethoate is twelve tim e s m o re toxic than di m e thoate in acute dietary exposure and three

tim es m o re toxic in chronic dietary exposure, residues of om e t hoate [including lim it of

detec tion (L OD) values] in/on th e sa m e sam p le were m u ltiplied by a tox i city ad justm e nt

factor (TAF) of 12 in the acute and by a factor of 3 in the chroni c dietary risk as sessm ent

before addition to dim e thoate residues. Exposure estim ates are reported in m illig ram s per kilogram of body weight pe r day, and risk is expressed as a percent of the aPAD or

cPAD. Exposure es tim ates th at are less than 100 % of the PAD are below the EPA’s level

of concern. For a m o re detailed discussi on on the relative toxici ty of omethoate, see

Section 4.3.8 of the human health risk assessm ent.

The estim ated drink i ng water concentr a tions (EDW Cs) were calcu lated for

multiple cro p s, includ in g those th at are th e m a jor use sites for dim e thoate, and other

representative sites. If appropriate, regional pe rcent cropp ed area facto r s (PCA) were

considered. EPA assum e d that dim e thoate woul d convert completely (100%) to

om ethoate during drinking water treatm ent, a nd therefore the TAFs were applied to the

acute and chronic exposure a ssessments, respectively. Pl ease see “A Re-assessm ent of

the Drinking W a ter Exposure Due to Di m e thoate Residues in Drinking Water,

Considering New Recommended Maxim u m Label Patterns from the Technical

Registrant” (Jones, R., 12/21/ 05) for detailed inform ation. Table 3 shows the highest

EDWCs, resulting from use on broccoli in Calif ornia (which is also representative of

cauliflower and celery) and the lowest EDW C s, r e sulting fro m use on pecans in Georgia.

Table 3. EDWCs for Dim e thoate on Selected Agricultural Crops.

Source Acute ED WC C h r oni c ED W C

-- -- -- -- -- -- -- -- -- -- - μ g L -1 di m e t hoat e e qui val e nt s -

- - - - - - - - - ­ ­

Surface Wate r

Bro c co li/Cau liflower/Celery 5 5 8 2 3 .5

Pecans 19.6 0.28

Grou nd Wate r

SC I- GR O W 0. 04 4 0. 04 4



### 9

### Surface water m onitorin g data are av ailab l e from a num ber of sources ; ho wever, they are lim ited in scope, are not nationally repr esentative, and did not include analysis of

om ethoate. The California Department of Pesticide Regulation (CDPR) conducted a

monitoring study in which sam p ling was done over several years. The highest

concentration of di m e thoate found was 2.4 μ g/L, in the San Joaquin River basin. Given

the sam p ling pattern and frequency within the study, it is uncer tain whether higher

concentrations would be observed at other tim es. The CDPR study did not m onitor for

om ethoate.

Ready to drink, treated drinking water da ta are not available for dim e thoate.

Di m e thoate converts to om ethoate to som e ex tent as a result of oxidation that occurs

when drinking water is treated via chlorina tion. One study has been conducted to test

conversion to om ethoate during chlorination; howeve r, the resulting data are lim ited in

scope. Due to the serious lim itations of th ese data, 100% conversion of dim e thoate to

om ethoate d u ring drinking water treatm ent of surface waters has been ass u m e d as a

protective m easure for this asse ssm ent. For m o re details on the conversion of di m e thoate

to om ethoate during drinking water treatm en t, see “A Re-assessm ent of the Drinking

Water Exposure Due to Di m e thoate Residue s in Drinking Water, Considering New

Recommended Maxim u m Label Patterns from the Technical Registrant” (Jones, R.,

12/21/05).

The ground water EDWCs were estim a te d using the SCI-GROW model, version

2.3. Since modeled EDWCs for ground water were m u ch lower than surface water

concentratio ns, only surf ace water EDWCs were used in th e dietary risk assessm ent.

Acute Dietary Risk Assessment for F ood + Water

Estim ated residues in drinking water were inco rp orated d i rectly into the acute

dietary assessm e nt. A re fined, Tier 3 assessm ent was conducted using the full

distribution of estim ated residues in su rface water, generated by the PRZM-EXAMS

model for dim e thoate use on California broccoli, the crop s c enario resulting in the h i g h est

estim ated peak surface water concentration, and for Georgia p ecans, th e crop scenario

resulting in the lowest estim ated peak surface water con centration.

Dietary risk from food al one occupies 32% of the aPAD. When food and water

are considered together, the resulting acute dietary exposur e and risk estim a tes for the

California b r occoli scen ario ex ceed EPA’s le vel of concern for all population subgrou ps.

Risk from aggregate dietary exposure on an acute basis occupies 460% of the aPAD for

the m o st highly exposed subgroup, infa nts less than one year of age.

10

### Table 4. Summary of Acute Dietary E xposure and Risk for Di m e thoate at 99.9 th



### Percentile

Po pul at i o n

Sub g r oup Food Only Fo od + Dri nki ng W a t e r (CA B r o c co li) Fo od + Dri nki ng W a t e r (G A Pec a ns )

Dietary

Ex pos u r e (m g/ kg/ day ) % aPAD Dietary

Ex pos u r e (m g/ kg/ day ) %

aPAD Dietary

Ex pos u r e (m g/ kg/ da

y) % aPAD

Gene ral US

Po pul at i o n 0. 00 2 1 3 4 16 0. 01 7 8 7 2 14 0 0. 00 2 1 6 0 17

In fant s < 1 y e a r 0. 00 1 9 5 8 15 0. 06 0 1 5 5 46 0 0. 00 2 4 1 9 19

C h i l d re n 1- 2

y ears ol d 0. 00 4 1 6 0 32 0. 02 6 5 2 0 20 0 0. 00 4 3 7 3 34



### Chronic Dietary Risk Assessment for Food + Water

A refined, Tier 3 chronic dietary exposu re assessm e nt was also conducted for the

supported food uses of dim e thoate and for dr inking water. Anticipated residues were

derived using field trial data, percent crop treated data, and, w h ere available, processing

factors.

For the chronic assessment, a single point estim ate (23.5 ppb) of dim e thoate

residues in s u rface water was used to assess expo sure from dr inking water. The

estim ated su rface water concentratio n repres ents the 90 th 

### percentile annual m ean concentration generated by the PRZM-EXAMS model for California broccoli, the crop

scenario resulting in the highest es tim ated annual m ean concentration.

Chronic dietary risks bas e d on this an alysis are b e low the Agency’s lev e l o f

concern for all population subgroups. Risk fr om aggregate dietary exposure on a chronic

basis occupies 33% of the cPAD for the m o st highly exposed subgroup, infants less than

one year of age.

Table 5. Summary of Chronic Dietary E xposure and Risk for Di m e thoate at 99.9 th



### Percentile

Po pul at i o n

Sub g r oup Food Only Fo od + Dri nki ng W a t e r (CA B r o c co li) Fo od + Dri nki ng W a t e r (G A Pec a ns )

Dietary

Ex pos u r e (m g/ kg/ day ) % cPAD Dietary

Ex pos u r e (m g/ kg/ day ) %

cPAD Dietary

Ex pos u r e (m g/ kg/ day ) % cPAD

Gene ral US

Po pul at i o n 0. 00 0 0 2 8 1. 3 0. 00 0 2 3 3 11 0. 00 0 0 3 1 1. 4

In fant s <1 y ear 0. 00 0 0 4 2 1. 9 0. 00 0 7 1 5 33 0. 00 0 0 5 1 2. 3

C h i l d re n 1- 2

y ears ol d 0. 00 0 1 1 1 5. 1 0. 00 0 4 1 6 19 0. 00 0 1 1 5 5. 2



### Dietary Risk Characterization

For regulatory purposes, the Agency has a ssum e d that 100% of the m odele d water

concentrations of di m e thoate will convert to om e t hoate duri ng drinking w a ter treatm ent.

11

### Therefore, the 12X toxicity facto r for acute a ssessm ents and the 3X toxicity factor for the

chronic assessm ents were applied directly to th e distribution of water re sidue values.

Data exist which indicate that in som e instan ces, conversion could be as low as 20%, but

these data have serious lim itations. The Agency is requ ir ing the reg i stran t to inv e stig ate

the rate and am ount of di m e thoate convers ion to om ethoate during water chlorination

under various water quality regim e s.

In light of the conservative assum p ti ons regarding conversio n to om ethoate, the

Agency considered surface water modeling resu lts from several crop an d regional

scenarios. T h e resulting aggregated food pl us drinking water values for dim e thoate are

above 100% of the aPAD for som e uses. Food alone represents 32% of the aPAD for the

most highly exposed population subgroup, and the addition of m odeled water residues

results in estim a tes belo w the Agency’s leve l of concern f o r severa l uses. Prelim inar y

DEEM m o deling showed that a peak water re sidue estim a te of 140 ppb is equivalent to

106% of the aPAD for food and water for the m o st exposed population. Of the 25

modeled scenarios, 17 resulted in peaks le ss than 140 ppb which is below the Agency' s

level of con cern prior to m itig ation and 8 scenarios resulted in peak res i d u es at 140 p pb

or greater. The m itigation the Agency is requ ir ing is expec t ed to redu ce drinking wa ter

estim ates for all sites ex cept bro ccoli, celery and caulif lower grown in co asta l Calif or

nia.

For broccoli, celery and cauliflower, m odeling was done for applications in the

winter seaso n (Novem b er and December), and the predicted w a ter concentrations were

high as a result of runoff from the high am ount of rain received in coastal California in

the winter. Sensitiv ity analyses were conduc ted to explo r e different m itigation op tion s

, and showed that reducing the num be r of app lications or prohibiti ng aer ial applic ation s did not result in drinking water risk estim ates below 100% of the aPAD (when added to

food risks). USDA provided refined usage inform ation indicating that w h ile several

application s a year are needed for these vege tables, dim e thoate is not used in Novem b er

and Decem ber in co astal areas of California. EPA then cons id ered th e effects of

changing the application tim ing to the fall or spring, or m odeling applications in other

areas of the country, and these considerations did result in m u ch lower values. The

Agency believes that when these facts are taken into account along with the conservative

assum p tion of 100% conversion to om ethoate during drinking water treatm ent, the

drinking water residues resulting from di m e thoate applications to these vegetables do not

pose dietary risks of concern.

3. Residential and Other Non-occupational Risk

All residential and other non-occupational uses of dim e thoate were voluntarily

cancelled in 2002 (Federal Register No tice/Vol. 67, No. 84/Wednesday, May 1,

2002/Notices/21669). T h erefore, EP A did not conduct a residential exposure and risk

assessm ent for dim e thoate.

12

### 4. Aggregate Exposure and Risk

(For a com p lete discussion, see Section 7 of the hum a n health risk assessm e nt.)

The Food Quality Protection Act (FQPA) a m endm ents to the Federal Food, Drug

and Cos m etic Act (FFDCA, Section 408(b)(2)(A) (iii) require “that th ere is a reasonable

certainty that no harm will result from aggreg ate exposure to pesticide ch em ical resid u e, including all anticipated diet ary exposures for which there is reliable inform ation.”

Aggregate exposure will typica lly include dietary exposures (food plus drinking water),

residential uses of a pesticide, and ot her non-occupational sources of exposure.

There are no residential or other non-occupa tional uses of dim e thoate. Therefore,

when addressing aggregate exposures, only th e aggregate dietary pathways of food and

drinking water were considered. S i nce drinki ng water was inc o rporated directly in to th e acute and chronic dietary asse ssm ents, the dietary risk estim ates discussed above reflect

total estim a ted acute and chronic agg r egate risks from di m e thoate.

Acute aggregate risk es tim a tes for food and drink i ng water ex ceed EPA’s level of

concern for all population subgroups when estim ated residues in drinking water from the

Calif ornia b r occoli scen ario a r e as se ssed. W h en m itigation ( i .e., reduced m a xim u m application rates, reduced num b ers of appli cations per year, and increased retreatm ent

intervals) is considered, food and drinking water residues from all other uses do not

exceed th e Agency’s level of concern. Chr onic aggregate risk estim ates for food and

drinking water are below the Agency’s le vel of concern for all population subgroups,

including the m o st highly exposed subgroup, infants less than one year of age.

5. Occupation al Exposure and Risk

(For a com p lete discussion, see section 9 of the hum a n health risk assessm e nt.)

Workers can be exposed to a pesticid e through m i xing, loading, and/or applying a

pesticide, or re-entering trea ted s ites. Occupation a l r i sk is m e asured by a Margin of

Exposure (MOE), which describes how close the occupational exposure com e s to a No

Observed Adverse Effect Level (NOAEL). Th e target MOE for dim e thoate is 100, which

include s the def a ult unce r ta inty f acto r s f o r in tersp ecies extrap olation and intraspe cies

variation. MOEs that fall below 100 i ndicate a possible n e ed for m itigation.

Occupational handler scenarios were asse ssed using the short- and interm e d iateterm endpoint for derm al and inhalation expos ures. The short- and interm ediate-term

derm al endpoint is a BMDL 10 

### of 18.67 m g /kg/day, based on a 28-day repeated dose

derm al toxicity study on rats. The short- a nd interm ediate-term inha lation endpoint is 0.1

mg/kg/day, derived from an inhala tion concentration level of 0.38 m g / m 3 

### (BMDL 10 

### ) from

a 28-day repeated dose inhalation study of om et hoate using rats. Derm al and inhalation

exposures w e re com b ined to assess handler risk.

Occupational handler risk estim ates have been assessed for short- and

interm ediate-term exposures. Most occupati onal exposures are expected to occur in a

13

### short-term pattern (up to 30 days), but so m e interm ediate-term (one to six m onth)

exposures are anticipated in som e handler exposure scenarios, particularly those

involving applications by commercial applicat ors to large-acreage crops (e.g., field corn,

wheat, alfalf a, cotton). Long-term exposures are those that w ould result f r om use of a

pesticide for m o re than several m ont hs in a single year, and are not expected for

dim e thoate.

No che m ical-specific data for assess ing worker exposures during pesticide

handling a c tivities wer e subm itted, so short- and inte rm ediate -term derm al and inha lation

exposures for handlers were developed using the Pesticide Handlers Exposure Database

(PHED) Version 1.1.

The Agency has determ ined that there ar e potential exposures to individuals who

m i x, load, apply, and otherwise handle di m e thoate during the usual use patterns

associa t ed w ith th e pestic ide. Sever a l m a jor occu pational exp o sure scen arios were

identified based on the type of equipm ent that potentially can be used to m a ke di m e t hoate

applic ation s

.

The calculations of short- and interm edia te-term total risks to handlers ind i cate

that m o st occupational handler risks are belo w the Agency’s level of concern (i.e., MOEs

are greater than 100) at som e level of risk m itigation. Table 6 below shows only thos e

handler scenarios for whic h MOEs are less than 100.

Table 6. Summary of Handler Scenarios with MOEs Less Than 100 W h en Assessed with

Maxim u m Feasib le Mitigation

Expos ure Sce n ario Crop M a x i mu m

App licatio n

Rate (lb s

a.i./A) Daily

Treated

Area

(Ac r es) MO E w /

M a x i mu m

Feasib le

Mitig atio n

C ont r o l s

C i t r us 2. 0 35 0 77 b

M i xi ng/ l o a d i n g l i q ui ds f o r

aerial and ch emig atio n

ap p lication s W ood y orn a men t als,

Christm a s tree

pl ant a t i o ns, a n d

coni fer seed orchards

(ot h er t h an Douglas

firs i n OR an d WA ) 2. 0 35 0 77 b

C o t t o n w oo d gr ow n

fo r pul p 4. 0 35 0 39 b

Wheat 0. 67 1, 20 0 67 b

M i xi ng/ l o a d i n g l i q ui ds f o r aerial app licatio n s Al fal f a, al fal f a gr ow n

fo r see d

, cotto n, field

co rn , pop co rn , gr ass

gr ow n f o r seed

, saffl owe r , so rg hum

,

an d so yb ean s 0. 5 1, 20 0 90 b

Mix i n g /lo ad ing wettab l e Pears 1. 0 35 0 68 b



### 14Expos ure Sce n ario Crop M a x i mu m

App licatio n

Rate (lb s

a.i./A) Daily

Treated

Area

(Ac r es) MO E w /

M a x i mu m

Feasib le

Mitig atio n

C ont r o l s

powders for ae rial and

chem igation applications 0. 75 35 0 91 b

M i xi ng/ l o a d i n g/ ap pl y i ng

l i qui ds wi t h hi gh p r ess u re

h a ndw and spr a yer s W ood y orn a men t als,

Christm a s tree

pl ant a t i o ns, a n d

coni fer seed orchards

(ot h er t h an Douglas

firs i n OR an d WA ) 0. 01 c 1, 00 0

g a llo ns 34 a

Aerial s p ray a p plications o f

l i qui ds Wheat 0. 67 1, 20 0 92 b

C o t t o n w oo d gr ow n

fo r pul p 4. 0 35 0 53 b

Ap pl y i ng l i qui ds wi t h

airb last/mistb l o wer sp rayers Do u g las fi r see d

orc h ar ds i n OR an d

WA 8. 3 20 76 b

a Max i m u m fea s ib le m i tig atio n m easu r e d e no tes ad d ition a l PPE (dou b l e layer clo t h i n g p l u s g l ov es and a

half-face or ful l -face respi r ator).

b M a xim u m feasi b l e m i t i g at i on m easure den o t e s e ngi neeri n g c ont rol s (i .e.

, cl ose d sy st em s f o r m i xers a n d

loade r s or clos ed ca bs for a pplicators).

c Expresse d i n l b s a

. i./gal



### Post-Application Occupational R i sk

For workers entering a treated s ite, re stricted entr y inte rvals (REIs) are calculated

to determ ine the m i ni m u m length of tim e require d before workers can safely reenter (i.e.,

MOEs ≥ 100). The postapplication occupational ri sk assessm e nt considered exposure to

dim e thoate from entering treated fields and orchards. Given the nature of activities in

these locatio ns, and the fact th at dim e thoate is applied at various tim es during plant

growth, contact with treated su rf ace s is lik ely. Po tential e xpo s u re scen ario s include key

tasks, such as harvesting, thinning, and pruning, as well as secondary tasks, such as

scouting, irrigating, and hand weed ing. Other tasks of concern were also identified for

corn (detassling) and herbaceous ornam e ntal s (tasks related to cutting carnations and

roses).

Postapplication exposures are infl uenced by geographic location and

environm ental conditions near the tim e of app lication and the type of plant to which the

application is directed. For m o st crops, data show that following applications in arid

areas (i.e., outdoor areas where average annual rainfall is less than 25 inches), residues

persist longer than in non-arid areas. As a result, estim ated REIs tend to be longer in arid

areas.

15

### Table 7. Summary of Postapplicatio n Risk Assessm ent for Di m e thoate

C r o p Gr ou p M a x Si ngl e

Ap p. Rate

(lb s a.i./A) Key Tas k s Seconda ry Tas k s

Transfe r

Coefficient REI (d ays) Seconda ry

Transfe r

Coefficient REI (d ays)

No nAri d Ari d No nAri d Ari d

En di ve,

escarole, kale

, leaf lettu ce,

mu s t a r d

gree ns, S w i ss chard, turnips 0. 25 2, 50 0

h a rv est, t h in 12 h r s 1 1, 50 0

scout &

irrigate 12 h r s 12 h r s

Peas 0. 16 2, 50 0

har v est 12 h r s 12 h r s 1, 50 0

scout &

irrigate 12 h r s 12 h r s

Brussels

sprouts 1 5, 00 0

har v est

, irrigate,

pr

u n e, t h i n

& tie 3 9 NA

Wheat 0. 67 1, 00 0

scout,

irrigate 1 12 h r s NA

Bean s, len tils,

celery 0. 5 2, 50 0

har v est 1 2 1, 50 0

scout &

irrigate 1 12 h r s

M e l ons,

wat e rm el ons 0. 5 2, 50 0 0

har v est

,

p r

un e & th in 1 2 1, 50 0

scout,

irrigate &

han d wee d 1 12 h r s

Tom a t o es 0. 5 1, 00 0

har v est

, prune, sta k e,

th in , tie &

train 12 h r s 12 h r s 70 0

scout &

irrigate 12 h r s 12 h r s

Aspa ra gus 0. 5 50 0

scout

&irrigate 12 h r s 12 h r s NA

Bro c co li,

cau liflower 0. 5 5, 00 0

har v est

, irrigate,

pr

u n e, t h i n

& tie 2 5 NA

Alfalfa,

alfalfa grown

fo r see d

, soybea ns,

saffl owe r

,

co tto n,

pot at oe s 0. 5 1, 50 0

scout &

irrigate 1 12 h r s NA

Field corn,

po pc or n 0. 5 1, 00 0

scout,

irrigate &

han d wee d 12 h r s 12 h r s NA

Grai n

sor g hum 0. 5 1, 00 0

scout, 12 h r s 12 h r s NA



### 16C r o p Gr ou p M a x Si ngl e

Ap p. Rate

(lb s a.i./A) Key Tas k s Seconda ry Tas k s

Transfe r

Coefficient REI (d ays) Seconda ry

Transfe r

Coefficient REI (d ays)

No nAri d Ari d No nAri d Ari d

irrigate

Herbace ous

or

nam e nt al s 0. 5 50 0

task s related

to cu t

flo w ers &

fo liag e

, except roses

& car nat i o ns 12 h r s 12 h r s 40 0

task s related

to nur ser y

crops,

except c u t

f l ow er s or

fo liag e 12 h r s 12 h r s

Pep p ers 0. 33 1, 00 0

har v est

, stake & tie 12 h r s 12 h r s 70 0

scout &

irrigate 12 h r s 12 h r s

D oug las Fir

Seed

Orc h ar ds in

OR a n d WA 8. 3 1, 00 0

scout,

irrigate &

weed 22 39 NA

C o t t o n w oo ds

gr ow n f o r pul p 4 1, 00 0

scout,

irrigate &

weed 14 24 NA

Conife r see d

orc h ar ds

(exce p t

Do u g las fi r

s e e d o r ch ar d s

in OR and

WA ) 2 1, 00 0

scout,

irrigate &

weed 7 11 NA

W ood y

or

nam e nt al s

and Christm a s

tree

p l an tation s 2 3, 00 0

p r

un e & th in 19 36 1, 50 0

har v est 13 14

Pecans 0.33 50 0

pr

u n e &

scout 12 h r s 12 h r s NA

1 3, 00 0 10 14 1, 00 0 2 4

Pears 0. 75 har v est

, prune, trai n

& tie 8 12 scout,

irrigate &

han d wee d 2 2

0. 5 5 7 12 h r s 12 h r s

2 24 36 1, 00 0 7 9

Citru s 1 3, 00 0

pr

u n e 13 14 scout,

irrigate &

han d wee d 2 4

0. 5 6 7 12 h r s 12 h r s

Cherries 1 3, 00 0

har v est &

pr

u n e 10 14 1, 00 0

scout,

irrigate &

han d wee d 2 4

0. 33 2 4 12 h r s 12 h r s



### The risk assessm ent indicates that R E Is of 12 hours are long enough for MOEs to

reach 100 fo r m a ny crops; however, acute toxi city of om ethoate was not taken into

consideratio n. If an active ingred ien t is cate gorized as a toxicity ca tegory I due to derm al

17

### toxicity, skin irritation, or eye irritation, the Agency requires a m i ni m u m of a 48-hour

REI. Data were not available on the acute t oxicity of om ethoate, but om ethoate is known

to form on plants after application; ther efore, EP A believes a m i nim u m REI of 48-hours

is appropriate for dim e thoate. This is consistent with curr ent labels.

EPA will not be se tting s e para te REI s f o r detass ling corn, f o r which propo sed

REIs are 4 and 15 days for non-arid and arid con d itions, resp ectiv ely, due to the fact that

this task is relevant only for seed corn, and dim e thoate is not registered for use on seed

corn.

6. Human Incident Data

For a review of the pesticide poisoni ng incident data for dim e thoate, EPA

consulted the following data bases: (1) O PP Incident Data S y stem ; (2) Poison Control

Centers; (3) California D e partm e nt of Pes tic ide R e gulation; a nd (4) Natio nal Pesticid e

Telecomm unications Network.

A review of the published incident data indicates that for outdoor agricultural

uses, the prim ary sources of occupational exposures associated with poisoning are

postapplication field residues and spray drift. Ris k s from agricultu ral us es appear to b e

som e what lo wer than with other insec tic id es. Dim e thoate has the highest reported

incidence of poisonings (none life-threatening) among OPs used in residential settings,

but all residential uses f o r dim e thoate were cancelled in 2002 (Federal Register

Notice/Vol. 67, No. 84/Wednesd ay, May 1, 2002/Notices/21669).

B. Environmental Risk Assessment

A summ ary of the Agency’s environ m ental ri sk assessm ent for dim e thoate is presented

below. The com p lete risk assessm ent is available in the public docket at

http://www.regulations.gov ( docket # EPA-HQ- OPP-2005-0084).

1. Environmental Exposure

a. Environmental Fate an d Transport

Di m e thoate is a highly mobile, re latively non-persistent organophosphate

insecticide. The prim ary route of dissipat ion is m i crobially-mediated hydrolytic and

oxidative degradation in aerobi c soil, particularly under m o is t conditions, with a half-life

of 2.2 days. Di m e thoate does not photodegrade. It hydrolyzes very slowly in sterile

buffered solutions at pHs 5 and 7 (156 and 68 days, respectively), bu t hydrolyzes rapidly

to desm ethyl dim e thoate and dim e thylthiophosp horic acid w ith a half-lif e of 4.4 days at

pH 9. The anaerobic half-life was found to be approxim a tely 22 days, with the m a jor

non-volatile degradate being desm ethyl dim e thoate.

In a soil colum n leachin g study, 72-100% of the applied radioactiv ity was eluted

from the colum n s (loam

, silt loam , sandy loam , and sand). A study m easuring th e

18

### volatility of dim e thoate from the soil surface sho w ed that vol atility is not a signific a nt

route of dissipation.

The prim ary toxic degradate, om ethoa te, was found under field conditions, though

it was not detected in the laboratory studies

. The presence of om ethoate has been

established through field studies in insects, plants, and m a mmals. Om ethoate was the

only degradate analyzed in the dim e thoate field dissipation study. The other degradates

identif i ed in the labo rato r y st udies were not included in the analysis because it is believed

that: 1) based on the aerobic soil m e tabolism study, they would not persist in the field;

and, 2) they are not toxi cologically significant.

b. Aquatic Organism Exposure

For exposure to aquatic fish and inv e rteb rates, E P A considers surface water on ly,

since m o st aquatic o r gan i sm s are not found in groundwater. S u rface water m odels are

used to estim a te exposure to freshw ater a quatic anim als, since m onitoring data are

generally not from studies targeted on sm all water bodies and prim ary stream s, where

m a ny aquatic anim als are found. The m odeling results used in risk calculations for

dim e thoate are detailed in “A Supplem ent to the Environm e n tal Fate and Ecological Risk

Assessm ent for the Re-registration of Di m e thoate,” dated January 13, 2006.

The Estim ated Environ m ental Concentr ation (EEC) values used to assess

exposure to aquatic anim als are not the sam e as the values used to assess hum a n dietary

exposure from drinking water sources. Unlik e the hum an drinking water assessm ent, the

assessm ent of aquatic environm ental concen trations accounts for exposure to parent

dim e thoate only. Om ethoate is not expected to be a m a jor degradate in water except as a

result of chlorination (i.e., dr inking water treatment). Also, f o lia r diss ipa tion da ta we re used in the modeling.

Several crop scenarios were ass e ssed in the ecolo g ical risk as sessm ent. The

California b r occoli scen ario represents th e agric u ltur a l use with the m a xim u m EEC, and

so was chosen for regulatory pur poses. The highest and lowest EEC values used to

assess exposure to aquatic anim al s can be found in Table 8 below

. For a c o m p lete listing

of EECs please refer to the ecolog i cal risk asses s m ent.

Table 8. Estim a ted Environm ental Concentrations ( μ g ai/L ) o f Di m e thoate in Surface

Water for Selected Use Patterns

Cro p Maximum

μg/L 4- Da y

μg/L 21 -D a y

μg/L 60 -D a y

μg/L 90 -D a y

μg/L

B r occ o l i

, C A 33 .4 32 .0 28 .2 21 .6 17 .7

Peas 1. 28 1. 20 0. 96 0. 60 0. 44



### 19

### c. Terrestrial Organism Exposure

The Agency assessed ex posure to terrestr ial organism s by fir s t predicting the

am ount of di m e thoate residues found on anim al food item s and then using infor m ation on

typical food consum ption by various species of birds and m a mmals to determ ine the

am ount of pesticide consum ed. The am ount of r e sidues on anim al feed item s is based on

the Fletcher nom ogram and the current m a xi m u m application rates and m i nim u m application intervals proposed by the technical registrant for dim e thoate. The Fletcher

nom ogram i s a m odel developed by Hoerge r and Kenaga (1972) and m o dified by

Fletcher (1994). For non-food uses, the Ag ency used a conservative estim a te of 25

applic ation s with a 3-day re-app lic ati on interval, since no m a xim u m numbers of

applications or m i ni m u m retreatm e nt interval s appear on current pr oduct labels or were

proposed by the registrant.

Terrestrial exposure estim a tes for avian and m a mmalian risk assessm ents were

derived using the TREX model (Version 1.1), which calculates the decay of a chem ica l

applied to su rfaces of food item s as single or m u ltiple app lic ations. A complete lis t of the

EEC values used to assess exposure to terrest rial anim als can be found in the ecological

risk assessm ent.

2. Environmental Effects (Haz ard)

a. Toxicity to Aquatic Organisms

Freshwater and Estuarin e/Marine Fis h

Di m e thoate is practically non-toxic to es tuarine/m a rine fish and m oderately toxic

to freshwater fish on an acute basis. Chronic toxicity testing with aquatic anim als

revealed reduced growth for freshwater fish (NOAEC = 0.43 mg/L). No data were

available on the chron i c effects of dim e t hoate on estuarine/marine fish. T a ble 9

summarizes the data that support the toxicity endpoints used in assessing the risks to fish.

Table 9. Summary of Acute and Chronic Toxi city Estim ates for Fish Using Technical

Grade Dim e thoate

Species Acut e To xi ci t y C h r oni c To xi ci t y

96

- h r LC 5 0

(m g/L) Acut e To xi ci t y (M RID ) NO AEC/L O A E C

(m g/L) Affected

En dp oi nt s

(M RID )

Rain bo w Trou t

Onc o r h y n chus mykiss 6. 2 Mo d e rately

t oxi c ( 400 940 -0 2) 0. 43/ 0. 84 R e duce d

gr owt h

( 431 063 -0 3)



### Freshwater and Estuarin e/Marine In verteb rates

Dim e thoate is consid ere d to be sligh tly tox i c to e s tuar ine/m a rine inve rteb r a tes and

very highly toxic to freshwater invertebrates on an acute basis. Ch ronic to xicity tes tin g with aquatic anim als revealed reduced gr owth, survival, and reproductive effects

(NOAEC = 0.04 m g /L) for freshwat er invertebrates. No st udies are available on the

chronic toxicity of dim e thoate to es tuarine/m a rine invertebrates. Table 10 provides a

20

### summary of the data that suppor t the toxicity end points used in assessing the risks to

aquatic invertebrates.

Table 10. S u mm ary of Acute and Chronic Toxi city Estim ates for A quatic Invertebrates

Using Technical Grade Di m e thoate

Species Acut e To xi ci t y C h r oni c To xi ci t y

96

- h r LC 5 0

(m g/L) Acut e To xi ci t y (M RID ) NO AEC/L O A E C

(m g/L) 96

- h r LC 5 0

(m g/L)

St one fl y

Pteronarcys

ca lifo rn ica 0. 04 3 ( 4 8

- h r) Very h i gh ly tox i c ( 000 035 03 ) ND * ND

Water flea

D aph n i a m agna 3. 32 ND 0. 04/ 0. 1 R e pr od uct i v e

, survival, growt h

( 428 647 -0 1)

Mysid shrim p

Mysid op sis bah ia 15 Slig h tly to x i c ( 427 600 -0 3) ND ND

*ND = Not d e te r m ined



### Aquatic Pla n ts

No toxicity data have b e en subm itted to the Age n cy f o r eithe r ter r es tr ial or

aquatic plants; however, inform ation from the ope n litera ture indica tes tha t dim e thoate is

highly toxic to blue-green algae.

b. Toxicity to Terrestrial Organisms

Birds

Di m e thoate is considered very highly t oxic to birds on an acute basis. Chronic

toxicity testing resulted in reproductive e ffects (reduced egg production and num b er of

viable em br yos), growth effects (reduced 14-da y survivor weight), and su rvival effects

(reduced number of 14-day survivors) in bi rds. The chronic NOAE C wa s 4 m g /kg diet.

Table 11. Summary of Avian Toxicity Data

Species LD 50 (m g/ kg) Acute Oral

Tox i city

(M RID ) 5- day LC 50 (p pm ) Subacute

Dietary

Tox i city

(M RID )

R e d- wi n g ed bl ackbi rd

Agel ai us ph oe ni ceus 5. 4 Very hig h ly

t oxi c ( 000 205 60 ) ND * ND

R i ng- nec k ed p h easa n t

Ph asi a nu s c o l c hi cus ND ND 33 2 High ly to x i c ( 000 229 23 )

*ND = Not d e te r m ined



### 21

### Table 12. S u mm ary of Avian Chronic Toxicity Data

Species NO AEC/

LOAEC (ppm )

(M RID ) A f f ected Endpo in ts

North e rn bob wh ite qu ail

Co lin u s virg i n ia nu s 4. 0/ 1 0

. 1

( 440 490 -0 1) Red u c ed egg pr odu ctio n, v i able e m b r yo s, 3­

week ol d em br

y o s, no rm al hat c hl i ngs

, 14 -da y

ol d su rvi v o r s, 14

- d ay ol d s u r v i v or wei ght

, a dul t

m a l e and fem a l e bo dy wei g ht , an d e g g s h el l

th ick n e ss



### No registran t -subm itted data a r e ava i lable with which to ev aluate th e toxicity of

om ethoate to birds and no data on avian species are available through ECOTOX.

Although the open literature sugge sts that birds can be partic ularly sensitive to the Oanalog (oxon) of phosphorodithioat e insecticides, there are no data currently available to

determ ine whether this is true for omethoate. Thus, the sensitivity of birds to om ethoate

is an unce r ta inty in the A g ency’s r i sk assessm ent.

Mamm als

Di m e thoate is m oderately toxic to mamma ls on an acute exposure basis. Data

fro m a develop m ental neurotoxicity study (NOAEC=0.1 m g /kg bw) were used to assess

the risk of chronic toxicity of dim e thoate to m a mm als. This endpoint is considerably

more sensitive than th at used in th e p r evious (1999) risk assessm e nt for dim e thoate. The

NOAE L fro m the develop m ental neurotoxicity study of rats is based on reproductive

im pair m e nt as m easured by decreased pup surviv al and increased percen tage of rat litters

lost. After treating m a ternal rats duri ng gestation and nursing, there was a dosedependent increase in p up death and litter loss.

Table 13. S u mm ary of Acute and Chronic Toxicity Data for Mamm als Exposed to

Di m e thoate

Species Acut e To xi ci t y C h r oni c To xi ci t y

LD 50 (m g/ kg) Acute Oral

Tox i city

(M RID ) 5- day

LC 50 (p pm ) Subacute

Dietary

Tox i city

(M RID ) NO AEC/

LOAEC (ppm )

(M RID ) A f f ected Endpo in ts

Lab o rato ry

m ouse

Mus

musc ul us 12 0 Mo d e rately

t oxi c ( 000 553 71 ) ND ND ND ND

Lab o rato ry

rat 42 0 Mo d e rately

t oxi c ND ND 32/ 40 0

m g / kg/ day

( 000 516 75 ) CHeI a n d decreased

weig ht

Ra ttu s

nor vegi c us ( 247 669 ) 0. 1/ 1. 0

m g / kg/ day

( 455 297 -0 3) Pup m o rtality



### Non-target Insects

Di m e thoate is characterized as highly toxic to bees on an acute exposure basis,

based on a honey bee acute contact study (LD 50 

### = 0.05 μ g/bee). Contact toxicity data on

parasitic wasps ( Bathyplectus curculionus ) ind i c a te th at som e be neficial insects m a y be

22

### considerably m o re sensitive than honeybees (LD 50 

### =0.00043 μ g/wasp) on an acute contact

basis.

3. Ecological Risk Estimation

The Agency’s ecological risk assessm e nt com p a r es toxi city endpoints from

ecological toxicity stud ies to es tim ated envi ronm ental concentrations (EECs) based on

environm ental f a te cha r a c ter i stics an d pesticide use data. To evaluate the potential ris k to

non-target organism s from the use of dim e thoa te products, the Agency calculates a Risk

Quotient (RQ), which is the ratio of the EEC to the m o st sensitiv e toxicity endpoint

values, such as the m e dian leth al dos e (LD 50 

### ) o r the m e dian lethal con centration (LC 50 

### ).

These RQ values are th en com p ared to the Ag ency’s levels of concern (LOCs), given in

Table 14, which indicate whether a pesticide, w h en used as directed, has the potential to

cause adverse effects on non-target organism s. When the RQ exceeds the LOC for a

particular category, (e.g., endange red species), the Agency presum es a risk of concern to

that category. These risks of concern m a y be addressed by f u rther refinem e nts of the risk

assessm ent or m itigatio n. Use, toxicity, fate, an d exposure are consid ered when

charac ter i z i ng the r i sk, as well as th e relativ e de gree of unce r ta inty in the assessm ent.

EPA further characterizes ecological risk ba sed on any reported incidents to non-target

terrestrial or aquatic org a nism s in the field (e.g., fish or bird kills ).

Table 14. E P A’s Levels of Concern and Associated Risk Presum ptions

Risk Pre s ump t ion LOC

terrestri a l

ani m al s LOC

a q ua t i c animals

Acut e Ris k

- t h ere i s p o t e nt i a l fo r ac ut e ri s k 0. 5 0. 5

Acute Endangered Species

- enda ngere d s p ecies m a y be

adve rsely affec t ed 0. 1 0. 05

Chr o nic Risk - th ere is po tential fo r chron i c risk 1 1



### For a m o re detailed exp l anation of the ecolog i cal risk s posed by the use o f

dim e thoate, refer to “A Supplem ent to the Environm ental Fate and Ecological Risk

Assessm ent for the Re-registration of Di m e thoate,” dated January 13, 2006.

a. Risk to Aquatic Organisms

Freshwater Fish and Inv e rteb rates

No acute RQs exceed the acute risk LOC for freshwater fish or inverteb rates (RQs

range from <0.01 to 0.03).

No chronic RQs exceed the chron i c risk LO C for freshwater fish (RQs ran g e from

<0.01 to 0.14). For freshwater invertebra tes, the only exceed ance of the LOC is

associated w ith use on C h ristm a s trees (RQ = 1.96). Risks to aquatic anim als from use of

dim e thoate on Christm a s trees was estim ated assum i ng 25 applications at the m a xi m u m labeled rate, with 3 day application interval s. This num ber of applications is likely

23

### greater th an the actual valu e, but was assessed because cu rrent labels do not specify

lim its. As a result of this reregistration decision, labels will be revised to lim it the

num b er of applications per season. For all other use scenarios, chronic RQs were below

the LOC.

Estuarine/Marine F i sh and Invertebrates

RQs were not calculated for estuarin e/m a rine anim als; however, since the acute

toxicity endpoints for estuarin e/m a rine fish and invertebrate s are considerably higher than

for their fre s hwater coun terpa r ts (LC 50 

### > 111,000 μ g/L for sheepshead m i nnow, and LC 50 

### = 15,000 μ g/L for m y sid shrim p ), the Agency believ es that none of the acute RQs would

exceed th e acute risk LOC. No chronic tox i city data are currently av ailable for

estuarine/m a rine fish or inve rteb rates

, and therefore chron i c risks could not be assessed.

b. Risk to Non -targe t Ter restr ial Org a nisms

Birds

Avian RQs were calculated based on m a xim u m r e sidues of dim e thoate on forage

item s following a single application and an LC 50 

### of 332 ppm from a subacute dietary

toxicity study on ring-necked pheasants. At rate s of 1 lbs a.i./A or less, the highest acute

RQ is for birds feeding on short grass (RQ = 0.72)

. At rates greater than or equal to 0.75

lbs a.i. /A, th e acute risk and endangered spec ies LOCs are exceeded for b i rds foragin g on short grass. The acute endangered species LO C is not exceeded for birds feeding on tall

grass and broadleaf plants/insects. In or der to reduce RQs to below the endangered

species LO C for the m o st vulnerable avian sp ec ies, rates would have to be reduced to a

single application of 0.13 lbs a.i. /A. Th is low rate would not be efficacio u s.

Following multiple app lica tions of dim e thoate, the acu te r i s k LOC is exceeded f o r all app lic ations equal to or grea ter th an 1 lbs a.i./A (RQ = 0.72). Mult iple applic ation s at

rates greater than 0.16 lbs a.i./A exceed th e endangered species LOC for herbivores

across a ll us es (Table 15 ). Mean av ian acute RQ s were not c a lculated f o r

m u ltiple

application s

, but would be expected to result in n o acute risk exceedances

, except with

applic ation rates greater than 1 lbs a. i. /A , but enda ngered spe c ies exceed an ces would still

occur.

Table 15. S u mm ary of Estim ated Acute Av ian RQs from Multip le Application of

Di m e thoate at Maxim u m Foliar Residues

Use Si te

Application Ra te

(# / y ea r / interv a l ) Food I t ems Maximum

RQ

Sh ort gra ss 0. 72

Citru s Tal l grass 0. 33

1

. 0 lb a.i./A

(2/ 3 1 ) B r oa dl eaf pl an t s / s m a ll i n sect s 0. 41

Fruits, pods, se eds, and large i n sects 0.05

B r occ o l i

, C a ul i f l o wer, C e l e ry Sh ort gra ss 0. 44



### 24Use Si te

Application Ra te

(# / y ea r / interv a l ) Food I t ems Maximum

RQ

0

. 5 lb a.i./A

(6/ 7 ) Tal l grass 0. 20

B r oa dl eaf pl an t s / s m a ll i n sect s 0. 25

Fruits, pods, se eds, and large i n sects 0.03

Sh ort gra ss 0. 37

Co tto n, Saf f l ow er Tal l grass 0. 17

0

. 5 lb a.i./A

(2/ 1 4 ) B r oa dl eaf pl an t s / s m a ll i n sect s 0. 21

Fruits, pods, se eds, and large i n sects 0. 02

Sh ort gra ss 0. 36

Alfalfa Tal l grass 0. 17

0

. 5 lb a.i./A

(1/ n a) B r oa dl eaf pl an t s / s m a ll i n sect s 0. 20

Fruits, pods, se eds, and large i n sects 0.02

LOC = 0.5 for acute ris k a n d 0.01 for enda ngere d s p ecies



### Chronic avian RQs exceed the LOC (RQ ≥ 1.0) by factors of one to 178 for nearly

all use scenarios at m a ximum residues. At m ean residue levels, RQs decrease by roughly

60%. Chronic RQ values based on m ean resi dues range from 0.28 to 63. At application

rates below 0.5 lbs a.i./A, the chronic risk LOC is not exceeded for birds feeding on

fruits, pods, seeds and large insects, however, if the retreatm e n t interval is reduced to 7

days, the L O C is exceeded. In order to reach maxim u m residues that do not result in RQs

exceeding th e chronic ris k LOC, the m a xi m u m single application rate wo uld have to be

reduced to 0 .016 lbs a.i. /A, a rate that is not efficacious.

Table 16. S u mm ary of Estim ated Chronic Avia n RQs from Use of Di m e thoate at Mean

Foliar Res i d u es

Use

App licatio n Rate (# /year /

in terv al) Food Item s Mean RQ

Citru s Sh ort gra ss 63 a

Tal l grass 27 a

1. 0 l b s a.i

. / A Broa dleaf plants/s m a ll insects 33 a

(2/ 3 ) Fru its, pod s, an d larg e in sect s 5

. 2 a

Bro c co li, Cau l i f lower, Celery Sh ort gra ss 13 a

Tal l grass 5. 5 a

0. 5 l b s a.i

. / A

(6/ 7 ) Broa dleaf plants/s m a ll insects 6.9 a

Fru its, pod s, an d larg e in sect s 1

. 1 a

Co tto n, Saf f l ow er Sh ort gra ss 11 a

Tal l grass 4. 7 a



### 25Use

App licatio n Rate (# /year /

in terv al) Food Item s Mean RQ

0. 5 l b s a.i

. / A Broa dleaf plants/s m a ll insects 5.8 a

(2/ 1 4 ) Fru its, pod s, an d larg e in sect s 0

. 9 1

Alfalfa Sh ort gra ss 11 a

Tal l grass 4. 5 a

Broa dleaf plants/s m a ll insects 5.6 a

Fru its, pod s, an d larg e in sect s 0

. 8 8

a Excee ds c h r o ni c ri s k l e vel o f c once r n (R Q ≥ 1.0)



### Mamm als

The acute m a mmalian risk assessm ent is based on a m ouse a c ute oral LD 50 

### of 120

mg/kg and RQ values are expressed as dos e-based values. T h e dose-based RQs are

calculated using a body weight-adjusted and co nsum ption-weight equivalent dose. By

expressing the Kenaga nom ogram es tim ated re sidues in terms of daily equivalent dose,

estim ated en vironm ental concentratio ns can then be com p ared to the dos e-based LD 50



### . After a single applicatio n rate of 1 lb a.i./A , the acute risk LOC is exceeded for m a mmals

weighing less than 35 gram s and feeding on short grass, tall grass, and broadleaf

plants/insects, with RQs up to 3.5.

Following multiple app lications of dim e thoa te at rates g r eater than 0.25 lbs a.i. /A,

the acu te ris k LOC is exceeded for s m all and interm ediate-s ized m a mmals feeding o n short grass (RQs range from 0.76 to 5.3). Th e acute endangered spec ies LOC is exceeded

across sm all and interm ediate-sized h e rbivor ous m a mmals at applic ation rates greater

than 0.16 lbs a.i./A.

Table 17. S u mm ary of Estim ated Acute Mamma lian RQs from Multiple Application s of

Di m e thoate at Maxim u m Foliar Residues

Use M a m m al i a n A c ut e R i sk Q uot i e nt s

App licatio n

Rate

(# /year /

in terv al) B ody Wei g ht ( g ) Short Gras s Tall Grass B r oa dl eaf

Plan ts/Sm a l l

Insects Fru its/Po d s/

Large Insects

Citru s 15 1. 8 0. 81 1. 0 0. 11

35 1. 5 0. 7 0. 85 0. 09

1. 0 lb s a.i./ A

(2/ 3 1 ) 1, 00 0 0. 81 0. 37 0. 46 0. 05

Bro c co li, 15 1. 10 0. 50 0. 61 0. 06

Cau liflo wer, 35 0. 93 0. 43 0. 52 0. 07

Celery

.5 l b s a.i./A

(6/ 7 ) 1, 00 0 0. 50 0. 23 0. 28 0. 03

Co tto n, 15 0. 92 0. 42 0. 52 0. 06

Saffl owe r 35 0. 78 0. 36 0. 44 0. 05



### 26Use M a m m al i a n A c ut e R i sk Q uot i e nt s

App licatio n

Rate

(# /year /

in terv al) B ody Wei g ht ( g ) Short Gras s Tall Grass B r oa dl eaf

Plan ts/Sm a l l

Insects Fru its/Po d s/

Large Insects

.5 l b s a.i./A

(2/ 1 4 ) 1, 00 0 0. 42 0. 19 0. 24 0. 03

Alfalfa 15 0. 89 0. 41 0. 50 0. 06

35 0. 76 0. 35 0. 43 0. 05

0

. 5 lb a.i./A

(1 ap p per

y ear) 1, 00 0 0. 41 0. 19 0. 23 0. 03



### As seen in T a ble 18 belo w, all uses o f di m e thoate result in R Q s which exceed the

chronic m a mmalian level of concern ba sed on a NOAE L of 0.1 m g /kg/day. For a

com p lete lis ting of m a mm alian RQs f o r both m a xim u m and m ean foliar residues, please

see Tables 28 and 29 of the environm ental ri sk assessm ent. For further infor m ation on

the chron i c risks to m a mm als, please see Section 5 “Risk Charact erization ” below.

Table 18. S u mm ary Estim ated Chronic Mamm a lian RQs from Multiple Applications of

Di m e thoate Based on Mean Foliar Residues

Use

App licatio n Rate B ody

Weig ht ( g ) Ma mm a lian Risk Quo tien t s

Short

Grass Tall Grass B r oa dl eaf

Plan ts/Sm a l l

Insects Fru its/Po d s/

Large

Insects Seeds

Citru s 15 1, 04 2 47 7 58 6 65 14

35 89 0 40 8 50 1 56 12

2. 0 lb s a.i./ A

(2/ 3 1 ) 1, 00 0 47 7 21 9 26 8 30 6. 6

Bro c co li, 15 63 9 29 3 35 9 40 8. 5

Cau liflo wer, 35 54 6 25 0 30 7 34 7. 6

Celery

0. 5 l b s a.i

. / A

(6/ 7 ) 1, 00 0 29 3 13 4 13 5 18 4. 1

Co tto n, Saf f l ow er 15 53 8 24 7 30 3 34 7. 5

35 46 0 21 1 25 9 29 6. 4

0. 5 l b s a.i

. / A

(2/ 1 4 ) 1, 00 0 24 7 11 3 13 9 15 3. 4

Alfalfa 15 52 1 23 9 29 3 33 7. 2

35 44 5 20 4 25 0 28 6. 2

0

. 5 lb a.i./A

(1 app per year) 1, 00 0 23 8 10 9 13 4 15 3. 3

LOC = 1. 0



### Non-targe t Plants

There are no available p l ant tox i city data on dim e thoate , so EPA has not

calculated risks to non-target plants.

27

### 4. Ecological Incidents

There are a total of 22 field incidents reported between 1972 and 2000. Most of

the reported incidents are not recent. Relative to othe r organophosphate pesticides,

dim e thoate was ranked 13th out of 32 organophos phate pesticides evaluated in term s of

the num ber of incidents reported in the Ec ological Incident Infor m ation System

.

The m a jority (73%) of reported incident s invo lv ed ter r es trial anim als and were

split equally between bir d s (8) and b ee-r e la ted (8 ) inc i dents. Canada gees e and ceda r waxwings were the m o st frequently affected birds. The num ber of geese killed ranged

from 25 to “hundreds” w h ile the number of wa xwings killed ranged from 60 to 80. All

of the incidents involving Canada geese (4) we re associated with th e use of di m e thoate

on alfalfa; of these, two were from t h e regist ered use of the pesticide (one of which was

for treated s eed) and two were a res u lt of accid e ntal m i suse. The three incidents

involving cedar waxwings were fr om the registered use of dim e thoate in the garden or on

woody ornam e ntals. Of the eight incidents involving bees, seven occurred in W a shington

State and were prim arily associated w ith the use of di m e thoate on beans and orchard

crops.

Of the five reported incide nts that involved aquatic anim als, one resulted from the

registered aerial use of dim e thoate, and that was on soybeans. In this incident, 9,237 fish

were reported killed with th e m a jority of affected fish being minnows (89%), sunfish

(6%), and sh ad (2%). F i ve turkeys w e re a l so re po rted k illed in this sam e incident. There

are insufficient details reported for the incide nt to determ ine whet her there were unusual

circum stances ( e.g. a rain event) which m a y have result ed in increased aquatic exposure.

The rem a ining four incidents affecting a quatic anim als were from intentional or

acciden t al m i suse; two were asso ciated with load ing areas, on e from use on tobacco an d

one from use on a lake.

The one incident reported to have invol ved damage to grass resulted from the

m i suse of dim e thoate on spray applic ations to len tils in W a shington; th e e x tent of

dam a ge to the grass is not reported. Ther e have been no other reported incidents of

phytoxicity resulting from di m e thoate use.

Consisten t with risk estim a tes for bird s, repo rts of non-target species m o rtality

have involved birds. Although risk quotients es tim a ted for fi sh do not suggest that fish

will be sub j e c t to a c ute mortality, in cident re por ts show that f r eshwate r f

i sh have bee n

affected.

5. Risk Characteriz a tion

Although RQs do not exceed lev e ls of concern for aquatic sp ecies, d i m e thoate has

been shown to be m oderately toxic to fish a nd highly toxic to aquatic invertebrates. This

is evid enced by reported f i sh kills ass o ciated with the use of dim e thoate, signif y ing the

possibility of aquatic effects.

28

### Di m e thoate was shown to be very highly toxic to som e species of birds by the

acute o r al ro ute. There are acu te LOC exceedan ces at the app lication rate of 1.0 lb ai/A

for s m all birds eating short grass, with a m a xi m u m RQ of 0.7. Organophosphorus

com pounds are known to be toxic to birds by de rm al and inhalation routes. There have

been several incidents involving birds includ ing large birds such as Canadian geese,

which m a y be the result of exposures by these non-dietary routes.

For chronic risks to bird s, the av ian assessm ent shows LOC exceedances with the

m a xi m u m RQs of 63 for two applications at 1 lbs ai/A, based on m ean foliar residues.

There are exceedances for acute ris k LO C for sm all m a mmals with the m a xi m u m

RQ of 2.6 for sm all m a mm als eating short gra ss treated with two applications of 1.0 lb

ai/A. There are no reported m a mmalian incident s resulting from acute toxicity exposures

to dim e thoate.

The highest estim ated ecological risk s from use of di m e thoate ar e ch ronic risks to

m a mmals, with RQs calculated using m ean fo liar residues ranging from < 1 to 1,092. The

high values are from two applications of 1.0 lb ai/A with a 3 day re -application interval.

Most applications are at a m a xi m u m of 0.5 lb ai/A which results in RQs around 220.

The endpoint used for risk assessm ent com e s from a developm ental neurotoxicity

study, which was conducted for the hum a n health risk assessm e nt. The e ndpoint used for

the ecological risk assessm e nt is rat pup m o rtality, observed at very low levels of

exposure (N OAEL of 0.1 m g /kg/ day). A different endpoint (cholinesterase inhibition)

from the sam e study wa s used for th e hum an hea lth risk assessm e nt because: 1) ChE

inhibition occurred at lower doses , and was therefore considered to be m o re protective for

hum a n health risks; and 2) the m echanism of the pup m o rtality is not well understood.

The Science Advisory Panel noted that the pup mortality observed in the DNT study is

dose-related, and the Agency believes that although pup m o rtality is not a standard

endpoint, it is an appropriate endpoint to use for chronic m a mm alian risk assessm ent.

The previous ecological chronic m a mmalia n risk assessm ent, dated January 23,

1998, was based on the standard two genera tion reproduction study. The endpoint f o r this study was a NOAE L of 32 m g / kg/day ba sed on m a ternal eff ects and decreased

reproduction. RQ calculated from this endpoint ranged from <1-10.

While there are differences in th e m a gn itude of the RQs from both assessm ents,

both sets of RQs indicate that potential for chronic, reproduc tive risk to sm all m a mmals

is very high. Applications of di m e thoate are m a de to large acreage cr ops such as alfalfa,

corn and cotton. It is expect ed that m a mmals whose forage range is sm a ll, will be

affected if they live in or near treated areas.

To reduce the chronic mammalian risk quo tien t below the Agency’s leve l of

concern, the application rate would have to be lowered to 0.02 lb ai/A, which would be

far below th e efficacious level for pest control. T h e Agency is requiring lowered

29

### application rates and lowered num bers of a pplications to reduce exposure for non-target

m a mmals, and thereby provide som e protection against population loss.

6. Endangered Species Consideratio n s

The Agency’s prelim inary risk asses s m e nt for endangered speci es i ndi cates t h at

RQs exceed the endangered species LOC for birds and m a mm als. Further, poten tial

indirect effects to any species dependent upon a species that experiences effects from use

of di m e thoate, can not be precluded base d on the screening level ecological risk

assessm ent. These findin g s are bas e d solely on E P A’s screening level assessm ent and do

not constitute “m ay affect” findings under the Endangered Species Act.

IV. Interim Ris k Management, Reregis tration, and Tolerance Reassessment

Decision

A. Determ inat ion of Rere gistra tion Eligib ility

Section 4(g)(2)(A) of FIFRA calls for th e Agenc y to dete rm ine, af ter sub m ission

of relevant data concerning an active ingred ient, whether or not products containing the

active ingredient are eligible for reregistrati on. The Agency has previously identified and

required the subm ission of the generic (tec hnical or m a nufacturi ng-use grade) data

required to support reregistration of produc ts containing dim e thoate as an active

ingredient.

The Agency has com p leted its review of subm itte d data and its assessm ent of the

dietary, occupational, and ecol ogical risks associated with the use of pesticide products

contain i ng the active ing r edien t dim e thoate

. Based on these data, the Agency has

sufficient infor m ation on the hum an health and ecological effects of dim e thoate to m a ke

its interim decisions as part of the tole rance reassessm ent process under F F DCA and t h e reregistration process under FIFRA, as am ended by FQPA, pending completion of the

cum u lative assessm ent of the organophosphate cla ss of pesticides, of which dim e thoate is

a m e mber. Additiona l m itigation m a y be nece ssary afte r this cum u lative assessm ent is

com p leted. The Agency has determ ined that products containing dim e thoate will be

elig ible for reregis t ration provided th at (i ) required product-sp ecific data are subm itted ; (ii) the risk m itigation m easures outlin ed in th is docum ent are adopted; (iii) lab e l

am endm ents are m a de to ref l ect these m easur es; a nd (iv) any a ddition a l m easures ne ede d

to reduce cumulative risks are adopted. Needed label change s and language are listed in

Section V. Appendix A is a deta iled table lis ting all d i m e thoate uses tha t are e ligib le f o r reregistration, or uses w h ich requ ire tole rances o r toleranc e consideration. Appendix B

identifies generic data requirem e nts that the Agency reviewed as part of its determ ination

of the interim reregistration eligibility of di m e thoate, and lis ts the subm itted studies the

Agency found acceptable. Data gap s are id en tified as either outstand i ng generic data

requirem e nts that have not been satisfied with acceptable data, or additional data

necessary to confirm the decision presented here.

30

### Based on its evaluation of di m e thoate, the Agency has determined that dim e thoate

products, unless labeled and used as specified in Sections IV and V this docum e nt, would

present risks inconsistent with FIFRA and FFDCA. Accordingly, s hould a registrant fail

to im plem ent any of the r i sk m itigatio n m easures identif ied in this docum ent, the Agenc y

m a y take regulatory action to address the risk co ncerns from the use of dim e thoate. If all

changes outlined in this docum ent are incorp orated into the product labels, then all

curren t r i sks f o r dim e thoate will be a d equate ly mitig ated f o r the purposes of this interim

determ inatio n under FIF R A. Additionally, once an endangered species assessm ent is

com p leted, further chang e s to th ese registra tions m a y be necessar y, as explained in

Section IV.D.3 of this docum ent.

B. Public Comments and Responses

Through the Agency

= s public participation process, EPA worked extens iv ely with

stakeholders and the public to reach the regul atory decisions for dim e thoate. During the

most recen t public com m e nt period on the risk assessm ents, which closed on Nove mber

7, 2005, the Agency received comm e n ts from five sources: Chem inova, the Natural

Resource Defense Council, The Rachel Cars on Council, and two private citizens. The

comments included som e urging the Agency to be m o re stringent in its regulation of

dim e thoate, as well as som e requesting that the Agency reta in certain u s es. These

comments, in their entirety, are available in the public docket (docket # O PP-2005-0084)

at http://www.regulations.gov

. EPA has prepared responses to these com m e nts and they

are posted in the docket, along with this IRED.

In addition, EPA worke d with USDA to solicit input from th e grower community

on the im portance of dimethoate use for thos e crops with < 1% of cropped area treated

with dim e thoate. EPA received m a ny comments from growers through th is process.

EPA has considered these comm ent s , and will b e respondin g to them through a form al

response to comments m e mo, whic h will be p l a ced in th e p ublic dock e t, along with this

docum ent.

The IRED and technical supporting docum e nts for dim e thoate are also available to

the public through EPA

= s electronic public docket and com m e nt system, the Federal

Docket Managem e nt System (FDMS), under [legacy] docket identi fication (ID) num ber

EPA-HQ-OPP-2005-0084. In addition, the dim e thoate IRED m a y be downloaded or

viewed through the Agency

= s website at

http://www.epa.gov/pesticides /reregistration/status.htm

.

C. Regulatory Position

1. Food Quality Protection Act Findings

a. A Risk Cup @ Determ ination

As part of the FQPA tolerance reas sessm ent process, EPA assessed the risks

associated w ith this organophosphate. The asse ssm e nt is for this individual OP, and does

31

### not attem p t to fully reassess these toleranc es as required under FQPA. FQPA requires

the Agency to evaluate food tolerances on th e basis of cum u l a tive risk from substances

sharing a co mmon m echanism of toxicity, su ch as the toxicity expressed by the OPs

through a common biochem i cal interaction with the cholinesterase enzyme. The Agency

has com p leted a rev i sed cum u lative r i sk a ssessm e n t for OPs (USEPA, 2002), which can

be found on the Agency’s website http://www.epa.gov/pesticides/cum ulative/rra-op/

. The Agency intends to is sue the f i na l tole ra nce reassessm ent reregis t ration decis i ons for

dim e thoate and the OPs in August 2006. Th e Agency m a y need to pursue further risk

m itigation f o r dim e thoate to addr ess any risk s ide n tif ied in the cum u lative assessm ent f o r

the OPs.

EPA has determ ined that risk from food (dietary sources only) exposure to

dim e thoate is within its own “risk cup.” An aggregate assessm e nt was conducted, and

considered exposures through food and drinki ng water. No residential uses or nonoccupational exposure scenarios exist. This assessm e nt showed that risks from food

alone are below the EPA’s level of concern, but that risks from food and drinking water

together are above the A g ency’s level of concern on an acute basis for all population

subgroups when surface water m odeling for som e of the vegetables is considered.

Exceedances of the level of c oncern result from estim ated res i dues of dimethoate and

om ethoate in drinking w a ter, which were esti m a ted using a conservative assum p tion that

100% percent of dim e thoate converts to om ethoate during drinking water treatm ent via

chlorination. Please refer to the dietary risk characterization s ecti on of this docum ent for

more information on the conservative a ssum p tions m a de in the drinking water

assessm ent.

The Agency is requ iring m itigation that is expected to redu ce the am ount of

dim e thoate that reaches surface water bodies, in cluding reducing applic ation rates and the

m a xi m u m num bers of applications per year, as well as increasing the number of days

between app lica tions. F o r citrus, a e r i al app lic ation will be p r ohibited. All application s to

citrus will also be prohibite d in Florida, since this use contributed to drinking water

concerns in previous ass e ssm ents. In additi on, the regis t rant will be requ ired to cond uct

studies evaluating the conversion of dim e t hoate to om ethoate during drinking water

chlorination under a variety of conditions. Given these requirem e nts, the Agency has

determ ined that the hum an health ris k s from these com b ined exposures w ill b e within

acceptable levels. In o t her words, E P A has m a de an interim decis i on (pending

cum u lative) that tole ranc es f o r dim e thoate m eet FQPA sa fety standards. In reaching this

determ inatio n, EPA has consider ed the available inf o rm ation on the spec ial sens itivity of

infants and children, as well as aggreg ate exposure from food and water.

b. Endocrine Disruptor Effects

EPA is required under the FFDCA, a s am e nded by FQPA, to develop a screening

program to determ ine whether certain substanc es (including all pes tic ide a c tive and other

ingredients) “m ay have an eff ect in hum a ns that is sim ilar to an effect produced by a

naturally occurring estrogen, or other endoc rine effects as the Adm i nistrator m a y designate.” Following recomm endat i ons of its E ndocrine Disruptor Screening and

32

### Testing Advisory Committee (EDSTAC), EPA de term ined th at the r e was a scien tif ic

basis for including, as part of the program

, the androgen and thyroid horm one system s, in

addition to the estrogen horm one sys t em

. EPA also adopted EDSTAC’s recomm endation

that EPA inc l ude eva l uations of pote n tia l ef f ects in wildlif e

. For pesticid es, EPA will use

FIFRA and, to the extent that effects in wildlife m a y help determ ine whether a substance

m a y have an effect in hum ans, FFDCA author ity to require the wildlife evaluations. As

the science develops and resources allow, screening of additional horm one system s m a y

be added to the Endocrine Disr uptor Screening P r ogram (EDSP).

c. Cumulative Risks

Dietary risks summarized in this docum e nt are those that result only from the use

of di m e thoate. The Food Quality Pro t ecti on Act (FQPA) requires that the Agency

consider “av ailab l e inform ation” concerni ng the cum u lative effects of a particula r pesticide’s residues and “other substances th at have a common m echanism of toxicity.”

The reason f o r consideration of other substances is due to the possibi lity that low- leve l

exposures to m u ltiple ch em ical substances th at cause a common toxic effect by a

common toxic m echanism could lead to the same adverse health effect as would a higher

level of exposure to any of the substances individually. Dim e thoate and om ethoate (not

registered in the U.S.) are m e mbers of the or ganophosphate (OP) class of pesticides. The

Agency has com p leted a revised cumulative risk assessm ent for OPs, ( USEPA, 2002 )

which can be found on the Agency’s web site

http://www.epa.gov/pesticides/cum ulative/rra-op /

. It assesses the cum u lative effects of

exposure to multiple OP s, includ ing dim e thoa te. The Agency intends to issue final

tolerance reassessm ent reregistration decisi ons for dim e thoate and the OPs in August

2006 and may need to p u rsue further risk m itig ation for dim e thoate to ad dress any ris k s

identif i ed in the cum u lative assessm ent f o r the OPs.

2. Interim Tolerance Summary

Toleranc es f o r res i dues o f dim e thoate in/on plant commoditie s [ 40 CFR

§180.241] are presently expressed in term s of the com b ined residues of dim e thoate and

its pr inc i pal m e tabolite, om ethoate. Followi ng e v aluation of plant m e tabolism studie s

, the Agency has determ ined that the appropria te dim e thoate residue s are those which are

currently regulated.

Additional residue data are needed to confirm the appropriateness of existing

tolerance levels. At such tim e as the additi onal field trial data are receiv e d and deem ed

adequate, th ese certain toleran ces may be revised; however, based on existing data,

dietary risks are below EPA’s level of concer n and EPA considers the tolerances to be

reassessed at their current levels.

The Codex Alim entarius Comm ission has established separate m a xi m u m residue

lim its (MRLs) f o r dim e thoate per se and om ethoate per se in /on var i ous commoditie s (see Guide to Codex Maximum Limits for Pest icide Residues, Part 2, FAO CX/PR, 4/93 )

resulting from application of the insecticides dimethoate , formothion, and om ethoate.

33

### Form othion and om ethoate are pr esently not registered for use in the U.S. The Codex

and U.S. tolerances are not harm onized with r e s p ect to MRL/tole rance expression since

the U.S. tole rance exp r es sion is in te r m s of the combined residues of dimethoate and

om ethoate, as a m e tabolite.

An interim s u mm ary of dim e thoate tolerance reassessm ent and

recomm ended m odifications in com m odity definitions is presented in T a ble 19,

below.

Table 19. Interim Tolerance Summary for Di m e thoate

Co mm o d ity Current T o lera nce (p pm ) Tolera nce

Reassessm ent (ppm ) Co mmen t/

[Co rrect Co mmod ity Defin iti o n ]

Tolerances Listed Und er 4 0 C F R § 180 .204 (a ):

Al fal f a 2 2 Sepa rat e t o l e ra nces s h oul d be

estab lish e d fo r Alfa lfa , forag e and

Alfa lfa , h a y

, ea ch at 2 ppm

Ap pl es 2 R e vo ke Use can celled 7 / 20 /05

. Ex istin g

sto c k s m a y b e so ld un til 7 / 20 / 0 6, an d

u s e m a y co n tinu e u n til sto c k s are depl et ed

.

Pears 2 2 C h an ge t o Pe ar.

Bean s, dr y 2 2 [ Bean , dried an d Bea n , su cculen t ]

Beans, lim a 2 2

Beans, sna p 2 2

B l ueber r i e s 1 1 C h an ge t o Bl ueberry

.

B r occ o l i 2 2

C a bba ge 2 R e vo ke Use can celled 7 / 20 /05

. Ex istin g

sto c k s m a y b e so ld un til 7 / 20 / 0 6, an d

u s e m a y co n tinu e u n til sto c k s are depl et ed

.

Cau liflo wer 2 2

C o l l a rds 2 R e vo ke Use can celled 7 / 20 /05

. Ex istin g

sto c k s m a y b e so ld un til 7 / 20 / 0 6, an d

u s e m a y co n tinu e u n til sto c k s are depl et ed

.

Kal e 2 2

M u st ar d gree n s 2 2

Cattle, fat 0

. 0 2 (N) 0

. 0 2 Neg lig i b le resid u e d e sign ation is

inappropriate. Ch ang e ca ttle, mb yp

to Ca ttle, mea t b y p r

o d u c ts Cattle, m b yp 0

. 0 2 (N) 0

. 0 2

Cattle, m eat 0

. 0 2 (N) 0

. 0 2

C e l e ry 2 2

En di ve (escar o l e) 2 2 C h an ge t o En div e

.

Let t u ce 2 R e vo ke Ch ang e t o Lea f

lettu ce

.

Use on head lettuce cancelled

7/ 2 0 / 0 5. E x i s t i n g st oc ks m a y be s o l d

u n til 7 / 2 0 / 06 , an d u s e m a y co n tin u e

u n til sto c k s are d e p l eted

.



### 34Co mm o d ity Current T o lera nce (p pm ) Tolera nce

Reassessm ent (ppm ) Co mmen t/

[Co rrect Co mmod ity Defin iti o n ]

Spi n ac h 2 R e vo ke Use can celled 7 / 20 /05

. Ex istin g

sto c k s m a y b e so ld un til 7 / 20 / 0 6, an d

u s e m a y co n tinu e u n til sto c k s are depl et ed

.

Swi ss c h ar d 2 2

Co rn

, fo dd er 1 1 Sepa rat e t o l e ra nces s h oul d be

estab lish e d fo r Co rn, field

, stover

( f

odder) and C o rn , po p, st ove r

( f

odder) , each at 1 ppm

. Cha nge to

C o r n

, fi el d, st o v er an d C o r n

, po p,

st ove r

C o r n , f o ra ge 1 1 [Co r n

, field , fora ge ] and C

o rn

, sweet, for age

C o r n , g r ai n 0. 1( N) 0. 1 Sepa rat e t o l e ra nces s h oul d be

estab lish e d fo r Co rn, field

, g r a i n and

C o rn , po p, gr a i n , eac h at 0. 1 ppm

. Neg lig i b le resid u e d e sign ation is

inappropriate.

C o t t onsee d 0. 1 0. 1 [ C ot t on, un del i n t e d seed ]

Eg gs 0. 02 (N ) 0. 02 Neg lig i b le resid u e d e sign ation is

inappropriate.

Goat s

, fat 0. 02 (N ) 0. 02 Neg lig i b le resid u e d e sign ation is

inappropriate. Change t o Goat, fa t

Go at

, me at by p r od uct s

, G o at

, meat Goat s

, m b y p 0. 02 (N ) 0. 02

Goat s

, m eat 0. 02 (N ) 0. 02

Gra p ef r u i t 2 2

Lem ons 2 2 C h an ge t o Le mon.

Ora n ges 2 2 C h an ge t o Ora nge

.

Tan g eri n e s 2 2 C h an ge t o Tang erin e.

Gra p es 1 R e vo ke Use can celled 7 / 20 /05

. Ex istin g

sto c k s m a y b e so ld un til 7 / 20 / 0 6, an d

u s e m a y co n tinu e u n til sto c k s are depl et ed

.

Ho gs, fat 0. 02 (N ) 0. 02 Neg lig i b le resid u e d e sign ation is

inappropriate. Change t o Hog, fa t;

Ho g, me at by p r od uct s ; H o g, meat Ho gs, m b y p 0. 02 (N ) 0. 02

Ho gs, m eat 0. 02 (N ) 0. 02

Ho rses, fat 0. 02 (N ) 0. 02 Neg lig i b le resid u e d e sign ation is

inappropriate. Ch ang e t o Horse, fat ;

Hor s e, me at by pro d u ct s;

Hor s e, me at. Ho rses, m b y p 0. 02 (N ) 0. 02

Ho rses, m eat 0. 02 (N ) 0. 02

Len tils 2

. 0 Rev o k e Th e estab lish e d to leran c e fo r p eas

ap p lies t o len t i l s.

M e l ons 1 1 C h an ge t o Mel on.



### 35Co mm o d ity Current T o lera nce (p pm ) Tolera nce

Reassessm ent (ppm ) Co mmen t/

[Co rrect Co mmod ity Defin iti o n ]

Milk 0

. 0 02(N) TBD On ce ou tstand i n g m e tab o lis m d a ta

are su b m itted

, th e av ailab l e

m a gni t ude of t h e resi d u e dat a f o r

milk will b e reev alu a ted an d

t o l e rance re vi si ons m a y be req u i r e d

. Neg lig i b le resid u e d e sign ation is

inappropriate.

Peas 2 2 [ Peas, d r ied and su ccu l en t ]

C h an ge t o Pea

, d r i e d a n d Pea

,

succ ulent.

Pecans 0.1 0.1 Change t o Pec a n.

Pep p ers 2 2 C h an ge t o Pe p p er

.

Tom a t o es 2 2 C h an ge t o T o m a t o

.

Pot a t o es 0. 2 0. 2 C h an ge t o P o t a t o

.

Po ul t r y

, fat 0. 02 (N ) 0. 02 Neg lig i b le resid u e d e sign ation is

inappropriate.

Pou ltr y, m b yp sh ou l d b e Pou ltr y,

m eat by pr od uc t s

. Po ul t r y

, m b y p 0. 02 (N ) 0. 02

Po ul t r y

, m eat 0. 02 (N ) 0. 02

Saffl owe r see d 0. 1 0. 1 [S a fflo wer, seed ]

Shee p, fat 0. 02 (N ) 0. 02 Neg lig i b le resid u e d e sign ation is

inappropriate.i n appropriate.

Shee p, m b yp s h ould be Shee p, m eat

b ypr odu cts. Shee p, m b y p 0. 02 (N ) 0. 02

Shee p, m eat 0. 02 (N ) 0. 02

Sor g hum , f o ra ge 0. 2 0. 1 Based on avail a ble field trial data,

HED rec o m m ends a l o we r tol e rance

.

Sor g hum , g r ai n 0. 1 0. 1 C h an ge t o S o r g h u m

, grai n, g r ai n.

Soy b ea ns 0. 05 (N ) 0. 05 Neg lig i b le resid u e d e sign ation is

inappropriate.

Change t o S o y b ean, see d

. Soy b ea ns , f o ra ge 2 2 C h an ge t o S o y b ean

, fo rage

. Soy b ea ns

, hay 2 2 C h an ge t o S o y b ean

, hay

.

Tur n i p s, ro ot s 2 0. 2 Based on avail a ble field trial data,

HED rec o m m ends a l o we r tol e rance

fo r di m e t hoat e resi d u es of co n cern

in /o n turn i p roo t s.

Sh oul d be T u r n i p

, r o ot s.

Tur n i p s, t ops 2 2 Sh oul d be T u r n i p

, t o ps.

Wheat

, g r ai n 0. 04 (N ) 0. 04 Neg lig i b le resid u e d e sign ation is

inappropriate.

Wheat

, g r ee n f o d d e r 2 2 [ W heat , f

o ra ge ]

Wheat, stra w 2 2

To lera nces Tha t N e ed To Be Propo s ed/Esta b lished U n der 40 C F R § 180 .2 04( a) :

C o w p eas, f o ra ge No ne TB D Tolera nces for these c o mm odities

will b e requ ired if th e reg i st ran t

w i sh es to suppo r t u s e of d i m e th o a te

on co w p eas gr ow n fo r l i v e s t o ck

feedi n g.



### 36Co mm o d ity Current T o lera nce (p pm ) Tolera nce

Reassessm ent (ppm ) Co mmen t/

[Co rrect Co mmod ity Defin iti o n ]

C o w p eas, hay No ne TB D

C o t t o n

, gi n by pr o duct s No ne TB D R e si due dat a a r e re q u i r e d

. Peas, fi el d, vi n e s No ne TB D Tolera nces for these c o mm odities

will b e requ ired if th e reg i st ran t

w i sh es to suppo r t u s e of d i m e th o a te

on field peas

.

C h an ge t o Pea

, fi el d, vi nes a n d Pea

, fi el d, hay Peas, fi el d, hay No ne TB D

Sor g hum , st o v e r ( f o d d er ) No ne 0. 1 C h an ge t o S o r g h u m

, grai n, st ove r.

Wheat hay No ne 2 ppm CBRS do es n o t ex p ect resi d u es in /on

w h eat h a y to be h i gh er th an t h e

to leran c e lev e l estab lish e d fo r wh eat

st raw. T h ere f o r e, a l e vel of 2 ppm

may b e pr opo sed f o r

w h eat hay.

Tolerances Listed Und er 4 0 C F R § 180 .204 ( b )

Aspa ra gus 0. 15 0. 15

Brussels sprout s 5 5 CBRS reco mmen d s th at t h is

to leran c e b e listed und er 40 C F R

§ 180 .2 04( a)

.

Cherries 2 2 Change t o Che rry.

Tolerances Listed Un der 4 0 C F R § 186 .210 0

Dri e d ci t r u s pu l p 5 R e vo ke R e vo ke d c onc om it ant wi t h t h e

estab lish m en t o f to leran ce for

[ C it rus, pul p, dri e d ]

- to b e li sted

un de r 40 C F R §1 8 0

. 2 0 4 ( a).



### D. Regulatory Rationale

The following is a summ ary of the rationale for m a naging risks associated with

the use of dim e thoate. Where labeling revisi ons are warranted, spec ific language is set

forth in the summ ary tables of Section V of this docum ent. In general, the application

rates and m a xim u m numbers of applications ha ve been reduced, and retreatm ent intervals

have been increased, to reduce dietary, worker , and ecological risks. These actions will

result in reduced exposure to dim e thoate. Table 20 lists all the use sites for which

applic ation r a tes and lab e l requ irem ents have been revised.

In order to reduce drinking water risk s of concern, applic atio n rates and the

num b er of applications are bei ng lowered for a number of crops

. Aerial applications are

prohibited for citrus and use is not allowed on citrus grown in Florida which contributed

to drinking water concerns in previous risk assessm e nts. In addition, best m a nagem e nt

practices (BMPs) will b e adde d to labels, with th e purpos e of reducing th e am ount of

dim e thoate that enters su rface water bodies th rou gh spray drift. These B M Ps include

requiring medium or coarser sprays for aerial ap plications and prohibitin g aerial sprays in

winds greater than 10 m iles per hour. To further reduce the amount of dim e thoate

entering surf ace water bo dies as runoff, the Agency recomm ends use of Vegetative Filter

Strips, if practical.

37

### In order to reduce occupational risk s of concern, in addition to reduced

applic ation r a tes and a re duction in n u m b ers of applica tions perm itted, h a ndlers will be

required to use additional protective equipm en t, such as additional PPE or engineering

controls, depending on the handler scenari o. All hum a n flaggers supporting aerial

applic ation s will be require d to be in closed c a bs

. Also, high pressure handwand

application s will be p r ohibited for app lications to woody ornam e ntals. Use on

cottonwoods grown for pulp will b e cancelled. See Table 20 b e low for detailed

m itigation which is required in ord e r for dim e th oate to b e eligible for reregistration. EPA

expects that these m itigation m easures will resu lt in MOEs of 100 or greater for m o st

handler s cen arios.

Postapplication risks will be reduced by extending REIs for som e crops, in

particular, orchard fruits and woody ornam e nt als. The occupational risk assessm ent for

dim e thoate indicates that REIs of 12 hours are adequate to reach MOEs of 100 for a

num b er of scenarios. However, when the acute toxicity of om ethoate is taken into

consideration, the Agency believes a 48 hour REI is m o re appropriate. Therefore, no

crop scenario has an REI shorter than 48 hours. This is consistent with current labels.

Regarding cole crops (broccoli, cauliflower, Brussels sprouts, and celery), the hum an

health risk assessm ent indicates that a five da y REI is needed to reach an MOE of 100 for

applic ation s in ar id are a s

. Growers of these crops indicated an REI of greater than 3 days

is not feasible for them ; EPA assessed the im pacts of this longer REI, and concurred.

Therefore, E P A is allowing an REI of 3 days fo r applications m a de to cole crops in arid

areas which results in an MOE of 89.

Risks to end a ngered sp ecies identified in the Environm ental Fate and Ecological

Risk Assessm e nt for di m e thoate are based solely on EPA' s screen ing lev e l assessm e n t

and do not constitu te "may effect" findings under the Endang ered Species Act. Rather,

this as sessm ent serv es as a screen to de term ine th e need for any species s p ecific

assessm ents that will evaluate whether exposur e m a y be at levels that could cause harm

to spec if ic listed spec ies and their cr itical h a bitat. That asses s m ent refines the screenin glevel assess m e nt to take into ac coun t the geographic area of pestic ide us e in re lation to

the listed sp ecies, the habits and habitat requirements of the listed species, etc. If the

Agency’s sp ecific as sess m e nts result in the need to m odify us e of the pesticide in spec if ic

geogrpahic areas, those changes to the pest icide’s regis t ratio n will take through the

process described in the Ag ency’s Federal Register No tice (54 FR 27984) regarding

im ple m entation of the Endangered S p ecies Protection Program.

The prim ary ecological risks of concer n are to birds and m a mmals on a chronic

basis. The Agency is attem p ting to reduce those risks by reducing application rates and

num b ers of applications, and in creasing application intervals.

38

### Table 20. Revised Use Site Paramete rs and Requirements for Dimethoate

Cro p App method Ma x

rate

per app

(lbs

a

. i./A) # apps/

interval REI ( d a y s )

Other No n-

ari d Arid

Cherries Aeri al 1 (SL N )

1 10 14 Aerial/Che migation: gl ove s

, ap r o n

,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Airblas t : M/L m u st wear gloves a n d

apr o n, A ppl i c a t ors m u st wea r gl o v es

and a respi r ator. Aerial,

chem igation,

and airblast 0. 33 2 4

Aspa ra gus Aerial,

chem igation,

g r ou ndb oo m 0. 5 2/ 1 4 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Citru s Ch em ig atio n

, and airblast 1 1 10 14 Proh i b it aerial ap p lication s

. Proh i b it all app licatio n s i n Fl o r i d a.

Chemi ga ti on : M/L m u st wear

gloves, apron, and res p irat or.

Airblas t : M/L m u st wear gloves a n d

apr o n, A ppl i c a t ors m u st wea r gl o v es

and a respi r ator.

Pears Aerial,

chem igation,

airb last (liqu i d

and WP) 1 1 10 14 For WPs: water-so l ub le p ackag ing

pl us gl oves an d a p r o n for M/L

Fo r liqu i ds:

Aerial/Che migation : gl ove s

, ap r o n

,

r e sp ir ato r fo r M/L;

Airblas t : M/L m u st wear gloves a n d

apron,

For both: Pilots in en clo s ed

cockpits, glove s and res p irator for

airb last app licato r s

Alfalfa (see d

and hay ) Aerial,

chem igation,

g r ou ndb oo m 0. 5 1 (pe r

cu ttin g) 2 2 Aerial an d Che m ig atio n : closed

sy st em s pl us gl ove s a n d ap ro n f o r

M/L; Pilo ts in en clo s ed co ck pits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Succ ulent

peas Aerial,

chem igation,

g r ou ndb oo m 0. 16 1 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Beans –

f r e sh , sn ap

, li m a , d r y Aerial,

chem igation,

g r ou ndb oo m 0. 5 2/ 1 4 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Bro c co li Aerial,

chem igation, 0. 5 3/ 7 2 3 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed



### 39Cro p App method Ma x

rate

per app

(lbs

a

. i./A) # apps/

interval REI ( d a y s )

Other No n-

ari d Arid

g r ou ndb oo m co ckp its.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Also : BMPs, v e g e tativ e filter stri p s

Cau liflo wer Aerial,

chem igation,

g r ou ndb oo m 0. 5 3/ 7 2 3 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r appl

. Also : BMPs, v e g e tativ e filter stri p s

Celery Aerial,

chem igation,

g r ou ndb oo m 0. 5 3/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Also : BMPs, v e g e tativ e filter stri p s

C o t t on Aeri al 0. 5 2/ 1 4 2 2 Aerial/ Chemi gation: cl ose d

sy st em s pl us gl ove s a n d ap ro n f o r

M/L; Pilo ts in en clo s ed co ck pits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Len tils Aerial,

chem igation,

g r ou ndb oo m 0. 5 2/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Also : BMPs fo r aer ial

M e l on Aerial,

chem igation,

g r ou ndb oo m 0. 5 2/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Also : BMPs

Po tato es Aerial,

chem igation,

g r ou ndb oo m (l i qui d a n d

WP ) 0. 5 2/ 7 2 2 For WPs: water-so l ub le p ackag ing

pl us gl oves an d a p r o n f o r M / L; Pi l o t s

in en cl o s ed cock p its; g l ov es fo r

g r ou ndb oo m ap p s

Fo r liqu i ds:

Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Also : BMPs



### 40Cro p App method Ma x

rate

per app

(lbs

a

. i./A) # apps/

interval REI ( d a y s )

Other No n-

ari d Arid

Soybea ns Aerial,

chem igation,

g r ou ndb oo m 0. 5 2/ 7 2 2 Aerial/Che migation: close d

sy st em s pl us gl ove s a n d ap ro n f o r

M/L; Pilo ts in en clo s ed co ck pits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Tom a toes Aerial,

chem igation,

g r ou ndb oo m 0. 5 2/ 6 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Field corn;

po pc or n Aerial,

chem igation,

g r ou ndb oo m 0. 5 1 2 2 Aerial/Che migation: close d

sy st em s pl us gl ove s a n d ap ro n f o r

M/L; Pilo ts in en clo s ed co ck pits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Saffl owe r Aerial,

chem igation,

g r ou ndb oo m 0. 5 1 2 2 Aerial/Che migation: close d

sy st em s pl us gl ove s a n d ap ro n f o r

M/L; Pilo ts in en clo s ed co ck pits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Sor g hum Aerial,

chem igation,

g r ou ndb oo m 0. 5 2/ 7 2 2 Aerial/Che migation: close d

sy st em s pl us gl ove s a n d ap ro n f o r

M/L; Pilo ts in en clo s ed co ck pits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Wheat Aerial,

chem igation,

g r ou ndb oo m 0. 5 1 2 2 Aerial/Che migation: close d

sy st em s pl us gl ove s a n d ap ro n f o r

M/L; Pilo ts in en clo s ed co ck pits.

Grou ndb oom: M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Pecans Aerial,

chem igation,

airblast 0. 33 1 2 2 Aerial/Che migation: gl ove s

, ap r o n

,

an d resp irat o r fo r M/L; Pilo ts in

e n c l o s ed co ck pits

. Airblas t : gl o v e s an d a p r o n fo r M / L;

glo v es a n d re s p irato r fo r a p p s

.

Peppers Aerial,

chem igation,

g r ou ndb oo m 0. 33 3/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: M/L m u st w e ar gl o v es a n d a p r o n

, gl o v es fo r applicators.

G r ass fo r

seed Aerial,

chem igation, 0. 5 2/ 9 0 2 2 Aerial/Che migation: M/L m u st

wear gl oves

, a p r o n, a n d re spi r at or s.



### 41Cro p App method Ma x

rate

per app

(lbs

a

. i./A) # apps/

interval REI ( d a y s )

Other No n-

ari d Arid

g r ou ndb oo m Pilo ts in en clo s ed co ckp its.

Grou ndb oom: g l ov es and ap ro n fo r

M / L; gl ove s f o r a ppl i cat o r s.

Leaf lettuce Aerial,

chem igation,

g r ou ndb oo m 0. 25 3/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators

Swiss c h ard Aerial,

chem igation,

g r ou ndb oo m 0. 25 3/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

En di ve (escarole) Aerial,

chem igation,

g r ou ndb oo m 0. 25 3/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Kale Aerial,

chem igation,

g r ou ndb oo m 0. 25 2/ 1 5 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Turnips Aerial,

chem igation,

g r ou ndb oo m 0. 25 3/ 7 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Mu stard

gree ns Aerial,

chem igation,

g r ou ndb oo m 0. 25 2/ 9 2 2 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Brussels

sprouts Aerial,

chem igation,

g r ou ndb oo m 0. 5 3/ 7 2 3 Aerial/Che migation: gloves , apron,

resp i r ato r fo r M/L; Pilo ts in en clo s ed

cockpits.

Grou ndb oom: : M/L m u st wear

gl o v es a n d a p r o n

, gl o v es fo r applicators.

Also : BMPs, v e g e tativ e filter stri p s

Herbace ous

or

nam e nt al s G r o und boo m

, low pressure

han d w an d 0. 25 1 2 2 Groundboom and Low Pre s sure

h a nd wa nd : M / L m u st wear gloves

an d apro n, G l ov es fo r a p plicators.

High Pressure Handwand: M/L



### 42Cro p App method Ma x

rate

per app

(lbs

a

. i./A) # apps/

interval REI ( d a y s )

Other No n-

ari d Arid

m u st wear gl oves a n d a p ron, Gloves

and res p irat or for applicators

. Do u g las fi r

seed

orc h ar ds i n

WA an d OR Ai r b l a st

- 4. 15 1 16 25 Airblas t : M/L m u st wear gloves a n d

apr o n, A ppl i c a t ors m u st wea r gl o v es

and a respi r ator.

Conife r see d

orc h ar ds Aerial,

G r o und boo m 1 1 2 4 Aerial: M/L m u st wear gl oves,

ap ron

, and respirato r

. Pilo ts in

e n c l o s ed co ck pits

. Grou ndb oom: M/L m u st we ar

g l ov es and ap ro n, G l ov es f o r applicators.

W ood y

or

nam e nt al s

and

Christm a s

tree

nu rse r i e s Aerial,

G r o und boo m 1 3/ 1 4 10 14 Aerial: M/L m u st wear gl oves,

ap ron

, and respirato r

. Pilo ts in

e n c l o s ed co ck pits

. Grou ndb oom: M/L m u st we ar

g l ov es and ap ro n, G l ov es f o r applicators.

C o t t o n w oo d

gr ow n f o r pul p Canceling us e

* E n close d c o c kpits a r e required for all aerial applications.



### 1. Significan ce of Use

Dim e thoate is a sys t em ic insec tic ide wh ich is widely used to control pests on

vegetable and row crops. It has a relatively short pre-harvest inte rval (PHI) and som e residual efficacy which often m a kes it a com pound of choice for fresh market v e getable

production.

During the three public comment periods on the dim e thoate risk assessm e n ts, the

Agency received m a ny grower comments in support of retaining dim e thoate use for

various crops.

EPA divided uses into two groups ba sed on percent crop treated. If a low

percen tage o f a crop is treated, the Agency m a kes the prelim inary assum p tion th at th e significance of use on that crop is also low. For these crops, the Agency consulted with

the USDA Office of Pest Managem e nt Policy ( O PMP) to determ ine whether ther e were

niche uses w h ich should be considered in a ny m itigation p l an. The twelve use sites in

this category are: alfalfa, cherries, citrus, cotton, corn (field and pop), grass grown for

seed, pears, pecans, pep p ers, safflower, a nd succulent p eas. OPMP received comm ents

from their Regional offices on dim e thoate us e. W h ile growers in som e regions do not

apply any dim e thoate on these crops, all twel ve sites had som e lim ited usage, prim arily

for control of flare-ups of spider m ites, th rips, aphids, or fleahoppers. There was also

som e occasional use for grasshopper contro l wh ich is not necessary every year, but for

43

### which dim e thoate was cited as a very im portant tool. The alternatives to these uses were

generally other organophosphates, carbam ates or pyrethroids. Seve ral regional experts

stated that many of the alternatives are restricted-use products, and so dimethoate

products are m o re attractive becau se dim e thoate is an efficacious general use com pound.

For the use s ites with gre a ter than 5% crop treated with dim e thoate, th e Agency

assum e d that the higher use frequency im plie d significance o f use. For these sites, the

Agency exam ined di m e thoate use patterns and av ailab l e a lte r n ative s and genera lly

evalua ted th e f easibility of extending restric t ed e n try in terv als (but not th e im pacts of

cancellation). Please ref e r to the Biol ogical and Econom ic Analysis Divisions

m e morandum entitled “Dimethoate application informa tion for specific crops (DP #

291616) ” and dated March 8, 2006. Through this assessm ent, the Agency concluded

that the requ ired worker m itigation will eff ectively reduce ris k without major im pacts on

the im portance of dim e thoate to users.

2. Spray Drift

The Agency has been working with the Spray Drift Task Force, EPA Re gional

Offices and State Lead Agencies for pesticid e regulation, and other parties to develop the

best spray drift m a nage ment practices. The Agency has com p leted its evaluation of the

new data ba se subm itted by the Spra y Drif t Task Force, a m e mbership of U.S. pesticide

registrants, and is developing a policy on how to appropriately apply the data and the

AgDRIFT c o m puter m o del to its risk assessm ents for pesticides applied by air, orchard

airb last and ground hydraulic m e thods. After th e policy is in place, the Agency m a y

im pose further refinem e nts in spray drift m a nage m e nt practices to redu ce of f

- target dr if t

and risks ass o ciated with aerial, as w e ll as other applica tion types, where appropriate.

From its assessm ent of dim e thoate as summarized in this docum e nt, the Agency

concluded that the m a jor source of dim e thoa te e n ter i ng surf a ce water bod ies is throug h

runof f

. Theref ore, the A g ency will r e quire that u s e of vegetative buf f e rs be encourag e d

on product labels

. The Agency is requiring m itigati on that will also red u ce the am ount

entering through spray drift. Nam e ly, aerial applications are being cancelled for a few

crops and labels will be revi sed to include best managem e nt practices including lowered

boom height and largest effective droplet size.

3. Endangered Species Consideratio n s

From the screening level assessm ent, RQs exceed the endangered species LOC

for som e of the representative exposure scenarios considered. At the rates assessed, acute

and chronic RQs exceed the LOC for endangere d birds and m a mmal acros s all us e sites.

After a single application of 0.16 lbs a.i./A, the endangered sp ecies acute and chronic risk

LOCs are exceeded for b i rds and m a mmals for som e use sites. Further, p o tential indirect

effects to any species dependent upon a speci es that experien ces effects from use of

dim e thoate, can not be precluded based on the sc reening level ecological risk assessm ent.

44

### The Agency has developed the Enda ngered Species Protection Program to

identify pesticides whose use m a y cause a dverse im pacts on endangered and threatened

species, and to im plem ent m itigation m easures that addr ess th ese im pacts. The

Endangered Species Act (ESA) requires federal ag encies to ensure that th eir action s a r e

not lik ely to jeopard ize listed sp ecies or adversely m odify desi gnated critical habitat. T o analyze the potential of regis t ered p e sticide us es that m a y affect any particular species,

EPA uses basic toxicity and exposure data developed for the REDs/IREDs and considers

it in relation to indiv i dua l spec ies and their loca tio ns by evalua ting im porta nt ecolog i ca l

param e ters, pesticide use inform ation, geogra phic relationship between specific pesticide

uses and species locations, and biological requirem e nts and behavioral aspects of the

particular species, as part of a refined sp ecies-specific analysis. W h en conducted, this

species -spe c i f i c analy s is will take in to consider ation any regu lato ry chang e s

recomm ended in this IR ED that are being im plem ented at that tim e

.

Following this f u ture sp ecies -spec i f i c analys is, a determ inatio n that there is a

likelihood of potential impact to a listed specie s or its critical hab itat m a y result in:

lim itations o n the use of dim e thoate, other m easures to m itiga t e any poten tia l im pact, or

consultation s with the F i sh and W ildlif e Service o r the Nation al Mar i ne Fisherie s Serv ice

as necess a ry

. If the Agency determ i n es use of dim e thoate “m ay affect” listed specie s or their design ated c r itica l habita t, EPA w ill em ploy the prov isio ns in the Se r v ices

regulations (50 CFR Part 402). Until that species-specific anal ysis is com p leted, the risk

m itigation m easures being im ple m ented th rough this IRED will reduce the likelihoo d that

endangered and threatened species may be expos ed to dim e thoate at levels of concern.

EPA is not requiring specific dim e thoate la bel language at the pr esent tim e relative to

threatened and endangered species. If, in the future, specific m easur es are necess a ry for

the protection of listed species , the Agency will im ple m ent them through the Endangered

Species Pro t ection P r ogram

.

V. What Registrants Need to Do

The Agency has dete rm ined that d i methoate will be elig ible f o r rer e gis t ra tion

provided that: (i) the risk m itigation m easures outlin ed in th is docum ent are adopted and

(ii) lab e l am endm ents are m a de to reflect these measures. To im plem ent the risk

m itigation m easures, the regis t rants must am end their product labeli ng to incorporate the

label sta t ements se t f o rth in the Lab e l Summ ary Table in Sec tion D belo w. The

additional d a ta requirements th at th e Agency intends to obtain will in clud e, am ong ot her

things, subm ission of the following:

A. For dim e thoate technical grade active i ngredient products , the reg i stran t needs

to subm it the f o llowing item s:

Within 90 d ays from receipt of the generic data call in (DCI):

1. com p leted response form s to the generic DCI (i.e., DCI response

for m and requirem e nts status and re gistrant’s response form ) ; and

45

### 2. any tim e extension and / o r waiver req u ests with a f u ll written

justif ication.

Within the time limit s p eci fied in the generic DCI:

1. citation of any existing generic data which address data requirem e nts

or subm it new generic data responding to the DCI.

Please contact Stephanie Plummer at (703) 305-0076 with questions regarding

generic reregistration.

By US m a il: By express or courier s e rvice :

Docum e nt Processing Desk (DCI/S RRD) Docum e nt Processing Desk (DCI/S RRD)

Stephanie P l umm e r Stephanie P l umm er US EPA (7508C) Office of Pesticide Program s (7508C)

1200 Pennsylvania Ave., NW Room 266A, Crystal Mall 2

Washington, DC 20460 1801 S. Bell Street

Arlington, V A 22202

B. For end-use products containi ng the active ingredient dim e thoate , the

registran t needs to subm it the following item s for each product:

Within 90 d ays from the receipt of th e product-specific da ta call-in (PDCI):

1. com p leted response form s to the PDCI (i.e., PDCI response for m and

requirem e nts status and regist rant’s response form ); and

2. subm it any tim e extension or waiver requests with a full written

justif ication.

Within eight months fr om the re ce ipt of the P DCI:

1. two copies of the confidential statem ent of for m ula (EPA Form 8570­

4);

2. a com p leted original application for reregistration (EPA For m 8570­

1). Indicate on the form that it is an “application f o r reregistration”;

3. five copies of the draft labe l inco rpor ating a ll lab e l am endm ents

outlin ed in Table 31 of this docum ent;

4. a com p leted for m certifying com p liance with da ta com p ensation

requirem e nts (EPA Form 8570-34); and

5. if applicab le , a com p leted f o rm certifying com p liance with co st share

offer requirem e nts (EPA Form 8570- 32); and

6. the product-specific da ta responding to the PDCI.

Please contact Venus Eagle at (703) 308-8045 with questions regarding product

rereg i stratio n and/or the PDCI. All m a teri als su bm itted in response to th e PDCI should

be addressed as follows:

46

### By US m a il: By express or courier s e rvice :

Docum e nt Processing Desk (PDCI/PRB) Docum e nt Processing Desk (PDCI/PRB)

Venus Eagle Venus Eagle

US EPA (7508C) Office of Pesticide Program s (7508C)

1200 Pennsylvania Ave., NW Room 266A, Crystal Mall 2

Washington, DC 20460 1801 South Bell Street

Arlington, V A 22202

A. Manufacturing Use Products

1. Additional Generic Data Requirements

The generic database supporting the inter i m of dim e thoate f o r the uses sp e c if ied in this

docum ent has been reviewed and determ ined to be substantially com p lete. However, the

data listed b e low are necessary to co nfirm the Interim Reregistra tion Elig ibility Dec i s i on

outlin ed in this docum ent.

Studies required for dim e thoate

850.1350 Mysid life cycle

850.1400 Estuarine/m a rine fish early life-stage

850.4225 Seedling em ergence (Tier II)

850.4250 Vegetative vigor (T ier II)

850.4400 Aquatic Plant (Tier II)

860.1380 Storage stability data fo r m eat, m ilk, poultry, and eggs

860.1500 Magnitude of residue on alfalfa grown for seed

860.1500 Magnitude of residue data for cotton gin byproducts

163-1 Batch equilibrium study

Non-guideline study Forestry field dissipation study (in support of poplar,

spruce seed orchard, and larch us es)

Non-guideline study Water treatm e nt a ssay to determ ine percent conversion

with chlo rin a tion in a va rie t y of water chem istrie s

The rereg i stration requ irem ents for the m a gn itude of residue in plants have been

f u lf illed f o r pea vines an d pea hay. The regis t ra nt m u st eith er petition th e Agency f o r the

estab lishm ent of toler a n ces f o r the total resi dues of di m e thoate a nd om ethoate in/on pea

vines and pea hay or am end product labels to re strict the use of di m e thoate to peas (not

including field peas).

Studies required for m e tabolites

850.2100 Acute oral (bobwhite quail a nd m a llard duck) – om ethoate

850.2200 Subacute dietary (bobwhite quail and m a llard duck) -

om ethoate

Reproduction (bobwhite quail and m a llard duck) –

om ethoate

47 850.2300

### 860.1500 Magnitude of residue data fo r m e tabolites of concern (Odesm ethyl om ethoate, O-desm ethyl om ethoate carboxylic

acid, and O-desm ethyl isodim e thoate)

Non-guideline study Com p arative cholineste rase study on rats for m e tabolites of

concern (O-desm e thyl om ethoate, O-desm ethyl om ethoate

carboxylic acid, and O-desm ethyl isodim ethoate)

B. End-Use Products

1. Additional Product-Sp ecific Data Requirements

Section 4(g) (2) (B) of FIFRA calls fo r the Agency to obtain any needed productspecific data regarding the pest icide a f ter a determination of eligibility has been m a de.

The registrant m u st review previous data s ubm issions to ensure they m eet current E P A

acceptance criteria and if not, comm it to conduct new studies. If a regi strant believes that

previous ly s ubm itted data m eet current tes ting s t andards, then the study M R ID num b ers

should be cited accord in g to the instructions in th e Requirem e nt Status an d Registrations

Response Form provided for each product. Th e Agency intends to issu e a separate

product-specific Data C a ll-In out lining specific data requirements

2. Labeling for End-Use Products

Labeling changes are necessary to implem e nt measures outlined in Section IV

above. Specific language to incorporate these changes is specified in Table 22.

Existing s t o c ks tim e f r am es will be estab lished on a case

- by -case b a sis, depending

on the num ber of products involved, the num ber of label changes, and other factors.

Please refer to "Existing Stocks of Pestic ide Prod ucts; Statem ent of Policy

, " Federa l

Register, Volum e 56, No. 123, June 26, 1991.

48Labeling Changes Summary TableIn order to beeligible for reregistration, amend all product labels to incorporate the riskmitigation measures outlined inSection IV.The following table describes howlanguage on the labels should be amended.Table 22.Label Changes Summary Table for DimethoateDescriptionAmended Labeling LanguagePlacement on LabelFor all ManufacturingUse Products“Onlyforformulation into an insecticide for the following use(s) [alfalfa,alfalfa for seed, asparagus, beans (excluding cowpeas), broccoli, Brusselssprouts, cauliflower, celery,cherries, Chinese cabbage, Christmas treefarms, conifer seed farms,cotton, endive, field corn,grass grownforseed, herbaceous ornamentals in commercial nurseries or greenhouses,grapefruit, leaf lettuce, lemons, lentils,kalemelons, mustard greens,oranges, pears, peas, pecans, peppers, popcorn, potatoes, safflower,sorghum, soybeans, Swisschard, tangerines, tangelos, tomatoes, turnips,watermelons,wheat, andwoody ornamentals in commercial nurseries orgreenhouses ].”“Not for formulation intowettable powder end use products (EUP),unless the EUP is packaged in water soluble bags.”Not for formulation intoend-use products intended for use byhomeownersor that permituse at residential sites.Directions for UseOne of these statementsmaybe addedto a labelto allow reformulationof the product for aspecific use oralladditional usessupported bya“This productmaybe usedto formulateproducts for specific use(s) notlisted on theMP label if the formulator, user group,orgrower hascomplied with U.S. EPA submission requirements regarding support ofsuch use(s).”“This productmaybe usedto formulateproducts for anyadditionaluse(s) not listed on the Manufacturing Use Product (MUP) label if theDirections for Use49formulator or usergroupformulator, user group, orgrower has complied with U.S. EPAsubmission requirements regarding support of such use(s).”Environmental HazardsStatements Requiredbythe RED andAgencyLabel Policies"Do notdischarge effluent containingthisproduct intolakes, streams,ponds, estuaries, oceans, orother watersunless in accordance with therequirementsof a National Pollution Discharge Elimination System(NPDES) permit and the permitting authorityhas been notified inwritingprior todischarge.Do notdischarge effluent containing this product tosewer systems without previouslynotifying the local sewage treatmentplant authority.Forguidance contact your State Water Board orRegional Office of the EPA."Precautionary StatementsEnd Use Products Intended for Occupational UsePPE RequirementsEstablished by theRED1For Wettable PowderFormulations (wettablepowder productsmustbe packaged in watersoluble bags tobeeligible forreregistration)“Personal Protective Equipment (PPE)”“Somematerials that are chemical-resistant to this product are”(registrant insertscorrect chemical-resistant material).“Ifyou wantmore options, follow the instructions forcategory”[registrant insertsA,B,C,D,E,F,G,or H]“on an EPA chemical-resistancecategoryselectionchart."“Mixers, loaders, applicators, and other handlers mustwear:>Long-sleeved shirt and long pants,> Shoes plussocks,> Chemical-resistant apron for mixersand loaders,> Chemical-resistant gloves.In addition, applicators using airblast orhighpressure handwandequipment, mustwear:> NIOSH-approved respirator withan organic-vapor-removing cartridgewith a prefilter approved forpesticides (MSHA/NIOSH approval number prefix TC-23C), ora canisterapproved forpesticides (MSHA/NIOSH approval number----Immediatelyfollowing/belowPrecautionary Statements:Hazards toHumans and DomesticAnimals50prefix TC-14G), or-- an organic-vapor-removing cartridgeor canister with anyN, R,P orHE prefilter.”“See Engineering Controlsfor additional requirements.”Instruction toRegistrant:Drop the “N” type prefilter fromthe respiratorstatement, if the pesticide product contains, or is usedwith, oil.PPE RequirementsEstablished by theRED1For LiquidFormulations“Personal Protective Equipment (PPE)”“Somematerials that are chemical-resistant to this product are”(registrant insertscorrect chemical-resistant material).“Ifyou wantmore options, follow the instructions forcategory”[registrant insertsA,B,C,D,E,F,G,or H]“on an EPA chemical-resistancecategoryselectionchart."Immediatelyfollowing/belowPrecautionary Statements:Hazards toHumans and DomesticAnimals“Mixers, loaders, applicators, and otherhandlers; mustwear:Long-sleeved shirt and longpants, and> Shoes plussocks,> Chemical-resistant apron for mixersand loaders,> In addition, all mixers and loaders, plus applicators using airblast orhighpressurehandwand equipmentmustwear chemical-resistant gloves.> In addition,mixers and loaders supporting aerial and chemigationapplications, and applicators usingairblast or highpressure handwandequipment mustwear:> NIOSH-approved respirator withan organic-vapor-removing cartridgewith a prefilter approved forpesticides (MSHA/NIOSH approval number prefix TC-23C), ora canisterapproved forpesticides (MSHA/NIOSH approval numberprefix TC-14G), oran organic-vapor-removing cartridgeorcanister with anyN,R, P orHE prefilter.”------51“See Engineering Controlsfor additional requirements.”Instruction toRegistrant:Drop the “N” type prefilter fromthe respiratorstatement, if the pesticide product contains, or is usedwith, oil.User SafetyRequirements“Follow manufacturer'sinstructions forcleaning/maintaining PPE.If nosuch instructions for washables exist,use detergent and hot water.Keepand wash PPE separatelyfromother laundry.”“Discard clothing and other absorbentmaterials that have been drenchedor heavilycontaminated with this product=s concentrate.Do not reusethem.”Precautionary Statements:Hazards toHumans and DomesticAnimalsimmediatelyfollowing thePPErequirementsEngineering Controls:(Water-SolublePackaging for WettablePowder Formulations)“Engineering controls”“Water-soluble packets, when used correctly, qualifyas a closedmixing/loading systemunder the Worker Protection Standard forAgricultural Pesticides[40CFR 170.240(d)(4)].Mixers and loadersusing water-soluble packetsmust :-- wear the personal protective equipment required in the PPE section ofthis labeling for mixersand loaders, and-- be provided and have immediatelyavailable for use in an emergency,such as a broken package, spill, or equipment breakdown:chemicalresistant footwear, and the type of respirator specifiedin the PPE sectionof this label.”“Pilotsmust use an enclosed cockpitthatmeets the requirements listed inthe Worker Protection Standard (WPS) for agricultural pesticides[40CFR 170.240(d)(6)].”Precautionary Statements:Hazards toHumans and DomesticAnimals(Immediatelyfollowing PPEand UserSafetyRequirements.)52Flaggers supportingaerial applications must use an enclosed cab thatmeets the definitionin theWorker Protection Standardfor AgriculturalPesticides[40 CFR 170.240(d)(5)]for dermal protection.Inaddition,flaggers must:-- wear long-sleeve shirt, longpants, shoes, socks and,--eitherwearthe type of respirator specified in the PPE section of thislabeling or use an enclosed cab that is declared in writing by themanufactureror bya government agency to provide atleast asmuchrespiratoryprotection as the respirator specified in this labeling,--be provided and have immediatelyavailable for use in an emergencywhen they must exit the cab in the treated area: coveralls, chemicalresistant gloves, chemical-resistant footwear, and chemical-resistantheadgear, if overhead exposure and,if using an enclosed cab thatprovides respiratory protection, a respirator of the type specified in thePPE section of this labeling,-- take off any PPE that was worn inthe treated areabefore reentering thecab, and-- store all such PPE in a chemical-resistant container, such as a plasticbag, toprevent contamination of the inside of the cab.”“When applicators use enclosedcabs in a manner that meets therequirementslisted in theWorker Protection Standard(WPS) foragricultural pesticides (40 CFR 170.240(d)(5), the handler PPErequirementsmaybe reduced or modifiedas specifiedin the WPS.”Engineering Controls:For LiquidFormulations“Engineering controls”‘Mixers and loaders supporting aerialorchemigation applications toPrecautionary Statements:Hazards toHumans and DomesticAnimals(Immediatelyfollowing PPEand Useralfalfa, cotton, soybeans, corn, safflower, sorghum, and wheat, must use aSafetyRequirements.)closed system that meets the requirements listed in theWorker ProtectionStandard (WPS) for agricultural pesticides [40 CFR170.240(d)(4)].Thesystemmust be capable of removing thepesticide fromtheshippingcontainer and transferring it intomixing tanksand/or application53equipment.At anydisconnect point, the systemmust be equipped with adrydisconnector drycouple shut-off device that is warranted bythemanufacturerto minimize drippage tonomore than 2ml per disconnect.In addition,mixers and loadersmust:-- wear the personal protective equipment required onthis labeling formixers/loaders, except that no respiratoris required;–wear protective eyewear, if the systemoperates under pressure; and-- be provided and have immediatelyavailable for use in an emergency,such as a broken package, spill, orequipment breakdown, chemicalresistant footwear and a respirator of the type specified in the PPE sectionof this labeling.”“Pilotsmust use an enclosed cockpitthatmeets the requirements listed inthe Worker Protection Standard (WPS) for agricultural pesticides[40CFR 170.240(d)(6)].”Flaggers supportingaerial applications must use an enclosed cab thatmeets the definitionin theWorker Protection Standardfor AgriculturalPesticides[40 CFR 170.240(d)(5)]for dermal protection.Inaddition,flaggers must:-- wear long-sleeve shirt, longpants, shoes, socks and,--eitherwearthe type of respirator specified in the PPE section of thislabeling or use an enclosed cab that is declared in writing by themanufactureror bya government agency to provide atleast asmuchrespiratoryprotection as the respirator specified in this labeling,--be provided and have immediatelyavailable for use in an emergencywhen they must exit the cab in the treated area: coveralls, chemicalresistant gloves, chemical-resistant footwear, and chemical-resistantheadgear, if overhead exposure, and,if using an enclosed cab thatprovides respiratory protection, a respirator of the type specified in thePPE section of this labeling,-- take off any PPE that was worn inthe treated areabefore reentering thecab, and-- store all such PPE in a chemical-resistant container, such as a plastic54bag, toprevent contamination of the inside of the cab.”“When handlers use closedsystems,or enclosed cabs in a manner thatmeets the requirements listed in the Worker Protection Standard (WPS)for agricultural pesticides (40 CFR 170.240(d)(4-5), the handler PPErequirementsmaybe reduced or modifiedas specifiedin the WPS.”User SafetyRecommendations“USER SAFETY RECOMMENDATIONS’‘Users shouldwash hands before eating, drinking, chewing gum, usingtobacco, or using the toilet.”“Users should remove clothing/PPE immediatelyif pesticide gets inside.Then wash thoroughlyandput onclean clothing.”“Users should remove PPE immediately after handling this product.Wash the outside of glovesbefore removing.As soon as possible, washthoroughly and change intoclean clothing.”Precautionary Statements under:Hazards to Humans and DomesticAnimals immediatelyfollowingEngineering Controls(Must be placed in a box.)Environmental Hazards“Do not apply directlytowater, or to areas where surface water ispresentor to intertidal areas belowthe mean high watermark.Do notcontaminatewater when disposing of equipment washwater or rinsate.”“Dimethoate is known to leach throughsoil intoground water undercertain conditions as a result of label use.Use of this chemical in areaswhere soils are permeable, particularlywhere the water table is shallow,mayresult inground-water contamination.”“This productmaycontaminate water throughdrift ofsprayinwind.This product has a high potential for runoff for several daysafterapplication after application.Poorlydraining soils and soils with shallowwater tables aremore prone to produce runoff that contains this product.”Precautionary Statements immediatelyfollowing the User SafetyRecommendations55“A level, wellmaintained vegetative buffer strip between areas to whichthis product isapplied andsurfacewaterfeatures suchas ponds, streams,and springs will reduce the potential forcontamination of water fromrainfall-runoff.Runoffof this product will be reduced byavoidingapplications when rainfall is forecasted to occur within48hours.”“A vegetative filter strip constructed and maintained in accordancewiththe 2000 Natural Resources Conservation Service publication"Conservation Buffers to Reduce Pesticide Losses"( http://www.nrcs.usda.gov/feature/buffers/) will significantlyreduce thepotential forcontamination of water fromrainfall-runoff."Restricted-EntryIntervals for productswith directions for usewithin the scope of theWorker ProtectionStandard (WPS) forAgricultural Pesticides(WPS)“Do not enter or allow worker entry into treated areasduring therestricted entry interval (REI).”In the Agricultural Use RequirementsboxEarly Entry PersonalProtective Equipmentfor products withdirections for usewithin the scope of theWorker ProtectionStandard (WPS) forAgricultural Pesticides“PPE required for earlyentry to treatedareas that is permitted under theWorker Protection Standardand thatinvolves contact with anything thathas been treated, such as plants, soil, orwater, is:> coveralls worn over long-sleeve shirt and long pants,> chemical-resistant gloves made of anywaterproofmaterial,> chemical-resistant footwear plus socks, and> chemical-resistant headgear (if overhead exposure)”Direction for UseAgricultural Use Requirements boxDouble NotificationStatement“Notifyworkers of the application bywarning themorallyand bypostingwarning signs at entrancesto treated area.”Direction for UseAgricultural Use Requirements box56General ApplicationRestrictions“Do not apply this productin a waythat will contact workers or otherpersons, either directlyor through drift.Only protected handlers maybein the area during application.”Place in the Direction for Use directlyabove the Agricultural Use Box.ApplicationRestriction“This productis for useincommercial setting only.Use in residentialsettings is prohibited.”Near the beginningof theDirections forUseCrop-SpecificApplicationRestrictions and REIsThemaximumapplication rate alsomust be statedin termsof the poundsorgallons of formulationLabelsmustbe amended to reflectthe following equipment restrictions,maximumapplication rates, retreatmentinterval, andthe maximumnumber of treatments per year:High Pressure Handwand Equipment:"When applications are madebyhigh pressure handwand equipment,the maximum application rate forall crops and use-patterns is 0.0025 pounds active ingredient per gallon."Alfalfa (grown forseed andforhay)Maximumapplication rate: 0.5 lbai/acre and no more than oneapplication per crop cycleor cutting.Maximum3 applications peryear.“The REI is 48 hours.”Asparagus, Beans (including fresh, snap, lima, and dry beans) andCottonMaximumapplication rate: 0.5 lbai/acre , 14dayretreatment interval andno more than 2 applicationsperyear. “The REI is 48 hours.”Field Corn and PopcornMaximumapplication rate: 0.5 lbai/acre and no more than oneDirections for Use associated with theuse directions for the specific crop towhich the restriction pertains57application per year.“The REI is 48 hours.PROHIBITION: Workers areprohibited fromentering the treated areato performdetasseling tasks for4 daysinnonarid areasand for 15daysinoutdoor areas where theaverage annual rainfall is less than 25 inches per year.”Broccoli, Brussels Sprouts, and CauliflowerMaximumapplication rate: 0.5 lbai/acre,7 dayretreatment interval andno more than 3 applicationsperyear. “The REI is 48 hours; however, theREI is increased to 72hours in outdoorareaswhere the average annualrainfall is lessthan 25 inches per year.”CeleryMaximumapplication rate: 0.5 lbai/acre,7 dayretreatment interval, andno more than 3 applicationsperyear. “The REI is 48 hours.”CherriesMaximumapplication rate: 0.33lb ai/acre and no more than oneapplication per year.“The REI is 48 hours; however, the REI isincreased to 4 daysinoutdoor areas where the average annual rainfall isless than 25 inches per year.”Note:There is anSLN for Cherries where the rate is1 lb.per acreandno more than one application peryear. “The REI is 10days;however, theREI is increased to 14days in outdoor areas where the average annualrainfall is lessthan 25 inches per year.” This information must be placedon the SLN labelCitrusMaximumapplication rate: 1 lb ai/acre and nomore than one applicationper year.“Do not applytocitrus inFlorida”“Aerialapplication to citrusis prohibited”“The REI is 10 days; however, the REI is increased to 1458daysinoutdoor areas where the averageannual rainfall is less than 25inches per year.”Conifer SeedOrchardsMaximumapplication rate: 1 lb ai/acre and nomore than one applicationper year.“The REI is 48 hours; however, the REI is increased to 4daysin outdoor areas where the average annual rainfall is less than 25 inchesper year.”Special Exception for airblast applications to Douglas Fir SeedOrchards in WA and OR onlyMaximumapplication rate: 4.15lb ai/acre.The limitof one applicationper year applies.“If airblast applications are applied at a rate greater than1 lb a.i/ acre, the REIis 16 days;however, the REI is increased to 25daysinoutdoor areas where the averageannual rainfall is less than 25inches per year.”Grass Grownfor SeedMaximumapplication rate: 0.5 lbai/acre 90 dayretreatmentinterval andno more than 2 applicationsperyear.“The REI is 48hours.”Herbaceous OrnamentalsMaximumapplication rate: 0.25lb ai/acre and no more than 1 applicationper year. “TheREI is 48 hours.”KaleMaximumapplication rate: 0.25lb ai/acre, 15 dayreapplication interval,and no more than 2 applicationsperyear. “The REI is 48 hours.”59Leaf lettuce,Swiss Chard,Endive and EscaroleMaximumapplication rate: 0.25lb ai/acre, 7 dayreapplication interval,and no more than 3 applicationsperyear. “The REI is 48 hours.”Lentils, Melon, Honeydew, andPotatoesMaximumapplication rate: 0.5 lbai/acre, 7 dayreapplication interval,and no more than 2 applicationsperyear. “The REI is 48 hours.”Safflower and WheatMaximumapplication rate:0.5 lbai/acre and no more than 1 applicationper year.“The REI is 48 hours.”Sorghum, and SoybeansMaximumapplication rate: 0.5 lbai/acre, 7 dayreapplication interval,and no more than 2 applicationsperyear. “The REI is 48 hours.”Mustard GreensMaximumapplication rate: 0.25lb ai/acre, 9 dayreapplication interval,and no more than 2 applicationsperyear. “The REI is 48 hours.”PearsMaximumapplication rate: 1 lb ai/acre and nomore than one applicationper year.“The REI 10 days; however, the REI is increased to 14 daysinoutdoor areas where the average annualrainfall is less than 25inches peryear.”PecansMaximumapplication rate 0.33 lbai/acre and no more than oneapplication per year. “The REI is 48 hours.”60PeppersMaximumapplication rate 0.33 lbai/acre, 7 dayreapplication interval,and no more than three applications per year. “The REI is 48 hours.”Succulent peasMaximumapplication rate 0.16 lbai/acre and no more than oneapplication per year. “The REI is 48 hours.”Note:There are SLN registrations for succulent peas for which the totalseasonal rateis not to exceed 0.5 lbs. a.i./acre.TomatoesMaximumapplication rate 0.5 lbai/acre, 6 dayreapplication interval, andno more than 2 applicationsperyear. “The REI is 48 hours.”TurnipsMaximumapplication rate 0.25 lbai/acre, 3 dayreapplication interval,and no more than 7 applicationsperyear. “The REI is 48 hours.”Woody Ornamentals and Christmas TreeNurseriesMaximumapplication rate 1.0 lbai/acre, 14 dayreapplication interval,and no more than 3 applications peryear.“Do not applyby high pressurehandwand toconifer and other ornamental tree crops”“The REI 10 isdays;however, the REI is increased to14 daysinoutdoor areas where theaverage annual rainfall is less than 25 inches per year.”SprayDrift“Requirements for Reducing Spray DriftDo not applyunder circumstanceswhere possible driftto unprotectedpersons or tofood, forage, or otherplantings that might be damaged orcrops thereof rendered unfitfor sale, use, or consumption can occur.Directions for Use611.Use the largest droplet size consistentwith acceptable efficacy.Formation ofverysmall dropletsmaybeminimized by appropriatenozzle selection, by orienting nozzles awayfromthe air streamasmuchas possible, and by avoiding excessive sprayboompressure.Forgroundboomand aerial applications, usemediumor coarser spraynozzles according toASAE 572definition for standardnozzles or avolumemeandiameter (VMD) of 300microns or greater for spinningatomizer nozzles.2.Make aerial or ground applications when the windvelocity favors ontarget productdeposition.Applyonlywhen the windspeed is less thanor equal to10mph.For all non-aerial applications, wind speed must bemeasured adjacent to the application site on the upwind side, immediatelyprior to application.3.Do not make aerial or groundapplications intoareas of temperatureinversions.Inversions are characterizedbystable air and increasingtemperatureswith increasing distance above the ground.Mist orfog mayindicate the presenceof an inversion inhumid areas.Where permissiblebylocal regulations, the applicator maydetect the presence of aninversion byproducing smoke andobserving a smoke layer near theground surface.4.Low humidityandhightemperaturesincrease the evaporation rate ofspraydroplets and therefore the likelihood of increased spraydrift.Avoid spraying during conditions oflowhumidityand/or hightemperatures.5.All aerial and ground application equipmentmust be properlymaintained and calibrated using appropriate carriers.6.Forgroundboomapplications, applywith nozzle height no more than4 feet above the ground orcrop canopy.7.For airblastapplications, turnoff outward pointingnozzles at rowends and when spraying the outer two rows.To minimize sprayloss overthe top in orchard applications, spraymust be directed intothe canopy.628.Forground-boom, chemigation, orchard, or other airblast applications,do not applywithin 25 feetof permanent water bodies (rivers, naturalponds, lakes,streams, reservoirs, marshes, estuaries, orcommercialfishponds).9.For aerial application topotatoes, donot apply within 150 feet ofpermanent water bodies (aquatic bufferzone).10.For aerial application tocrops otherthan potatoes,do not applywithin 50 feetof permanent water bodies (aquatic buffer zone).11.For aerial applications, releasespray at the lowest height consistentwith efficacyand flight safety.Ifthe application includes an aquaticbuffer zone, do not release sprayat a height greater than 10 feet above theground or cropcanopy.12.For aerial applications, the spray boomshould be mounted on theaircraft so asto minimizedrift caused by wing tipvortices.Theminimumpractical boomlength shouldbe used andmust not exceed 75%of the wingspan of 90%ofrotor blade diameter.Useupwind swathdisplacement.1PPE that is established on the basis ofAcute Toxicity of theend-use product must be compared to the active ingredientPPE inthis document.The moreprotective PPE must be placed in theproduct labeling.For guidance on which PPEis considered moreprotective, see PR Notice 93-7.63