Page 1 of 15 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, DC 20460 OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES MEMORANDUM DATE : 19 January 20 1 0 SUBJECT: Thifensulfuron Methyl. Petition to Estab lish a Permanent Tolerance

(Associated with Regional Section 3 Registration) for Residues Resulting from Food/Feed Use of the Herbicide on Safflower. Summary of Analytical Chemistry and Residue Data. PC Code: 128845 DP Barcode: D 361945 Decision Numb er : 405073 Re gistration Number : 352 - 633 Petition Number : 9F7523 Regulatory Action: Amended Section 3 Risk A ss essment Type : N A Case Number : NA T XR Number : N A CAS Number : 792 7 7 - 27 - 3 MRID Number : 47641801 40CFR: §180.439 Chemical Class: Triazi nylsulfonylurea Herbicide Trade Name: DuPont TM Harmony® SG FROM: William T. Drew, Chemist

Ris k A ssessment Branch 2 (RAB2) Health Effects Division (HED), 7509P THRU: Dennis McNeilly , Chemist

RAB2/ HED, 7509P TO: Barbara Madden, RM Team 5

Risk Integration, Minor Use and Emergency Response Branch (RI MUERB) Registration Division (RD), 7505P This residue chemistry summary document was originally prepared under contract by Dynamac Corporation (1901 Research Boulevard, Suite 220; Rockville, MD 20850). It has been reviewed by the Health Effects Division (HED) , and revised to reflect current Office of Pesticide Programs (OPP) policies.Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 2 of 15 Executive Summary Thifensulfuron methyl is a sulfonylurea herbicide (Group 2) registered to E.I . DuPont de Nemours for the control of broadleaf weeds on cereal grains (barley , field corn , oat, rice, sorghum, triticale and wheat), canola, cotton, flax and soy beans. The current registered use patterns on these crops includ e post - emergence, and pre - plant or at - planting burndown. Thifensulfuron methyl is absorbed through the foliage of treated weeds, inhibiting growth , causing necrosis of the growing plant , and eventual plant death. The Interregional Research Project Numb er 4 (I R - 4), has submitted a tolerance petition, 9F7523, proposing the establishment of a tolerance for “combined” residues of the herbicide thifensulfuron methyl ( with the CAS name of methyl - 3 - [[[[(4 - methoxy - 6 - methyl - 1, 3, 5 - triazin 2 - yl )amino] carbonyl] amino] sulfonyl] - 2 - thiophenecarboxylate) in or on safflower seeds, the raw agricultural commodity (RAC) , as listed below.

Safflower, seed ................................ ................................ ..... 0.05 ppm The end - use product (EP) proposed for use on safflower is DuP ontTM Harmony® SG Herbicide (EPA Registration # 352 - 633), a soluble granule (SG) formulation containing 50% (by weight) thifensulfuron methyl as the active ingredient (ai) . Harmony® SG is proposed for one post - emergence broadcast foliar spray o n safflower at a maximum application rate of 0.019 pound ai per acre ( lb ai/A ), with a pre - harvest interval (PHI ) of 81 day s. Application may be made up to the time of flower bud initiation , using ground or aerial equipment , with adjuvants in the spray mixture. The p roposed use is limited to safflower grown in the states of North Dakota, South Dakota, Nebraska, Montana (East of Route 87 or East of I - 15), and Wyoming (East of I - 25 or North of I - 90) . Tolerances for residues of thifensulfuron methyl are listed under 4 0CFR §180.439 [a] . Permanent tolerances are establ ished for thifensulfuron methyl in/on barley , canola, corn, cotton, flax, oat, rice, sorghum, soy bean , and wheat commodities , at levels ranging from 0.02 to 2.5 ppm. No tolerances are currently established for residues in animal commodities or rotational crops. The nature of the residue in plants is adequately understood , based on acceptable studies with wheat, corn and soy

beans. The metabolism of thifensulfuron methyl in tested crops proceeds by

hydrol ys is of the methyl ester and sulfonyl urea moieties, with some demethylation of the triazine methoxy

group. HED has previously determined that the residue of concern (ROC) in plant commodities is thifensulfuron methyl for the purposes of tolerance e nforce ment , and risk assessment. The available plant metabolism studies are adequate to support the requested use on safflower. The nature of the residue in livestock is adequately understood , based on the available goat metabolism study . This determination is based on the low level of transfer of thifensulfuron methyl residues to goat matrices , and the lack of detectable residues in livestock feed items, even at exaggerated application rates. HED conclude d that , because no detectable residues of thifensulf uron methyl were found in registered poultry feed items, a poultry

metabolism study

is not required. HED has previously determined that the ROC in plant commodities isThifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 3 of 15 thifensulfuron methyl for the purposes of tolerance expression , and risk assessment. T he current safflower petition does not alter HED’s earlier conclusions regarding livestock metabolism. Two high performance liquid chromatography ( HPL C ) photo - conductivity detection methods (Methods AMR - 646 - 86 and AMR - 761 - 87) are available for enforcing tolerances for residues of thifensulfuron methyl in cereal grains and straw. A liquid chromatography with mass spectrometric detection ( LC /MS ) method (DuPont Method 1381) is also available for enforcing tolerances for residues of thifensulfuron methyl in canola, cotton and flax commodities ; the validated limit of quantitation (LOQ) for this method is 0.02 0 ppm. The L C/MS method will be suitable for enforcing the proposed tolerance in safflower seed . The FDA multiresidue methods are not suitable for tole rance enforcement , as thifensulfuron methyl is not recovered through any of the FDA Multiresidue Method Testing protocols. Samples collected from the safflower field trial and processing studies were analy zed for residues of thifensulfuron methyl using an HPL C photo - conductivity

method (DuPont Method AMR - 973 - 87). The method was adequate for data collection based on acceptable method validation and concurrent method recoveries. The available storage stability data adequately

support the sample storage d uration s and conditions incurred dur in g the safflower field trial and processing studies . No storage stability corrections need to be applied to the safflower field trial and processing study results . According to OPPTS Residue Chemistry Test Guideline 860. 1000 , Table 1 Feedstuffs ( June 200 8 ), safflower meal is the only animal feed stuff associated with the current petition. Safflower meal may

constitute up to 5 % of beef cattle diet, 10% of dairy cattle diet, 25% of poultry diet, and 5 % of swine diet. Inconsideration of the proposed regional use of thifensulfuron methyl on safflower , and the observed residue s of < 0.050 ppm in safflower meal, the potential contribution to the maximum reasonably balanced dietary

burdens of livestock is negligible. There fore, tolerances in meat, milk, poultry and eggs are not required for this petition. The submitted residue data for safflower seeds are adequate to fulfill data requirement s for the requested use in the states of North Dakota, South Dakota, Nebraska, Mo ntana (East of Route 87 or East of I - 15), and Wy oming (East of I - 25 or North of I - 90) . The number and location of the safflower field trials support the requested regional use of Harmony® SG on safflower. The data reflect the proposed use pattern , which involves a maximum use rate of 0.019 lb ai/A, a minimum PHIof 81 day s, and use of a non - ionic surfactant (NI S) in the spray mixture. HED concludes that the propose d tolerance of 0.05 ppm is appropriate. The submitted safflower processing study showed that residues of thifensulfuron methyl were < 0.050 ppm in safflower meal , and refined oil , processed from safflower seeds treated at a 1X rate . DuPont has previously submitted a processing study depicting the magnitude of thifensulfuron methyl residue in cotton seed s . Residues of thifensulfuron methyl were non detectable ( < 0.006 ppm) in cotton seed s harvested at normal maturity (133 day s after treatment) following a single defoliant broadcast application of the 50% ai dry flowable (D F) formulation at 0.094 lb ai/A (roughly

4 X the normal use rate) , made one day after planting of cotton. The requirement for processing studies in canola and flax has previously been waived, based on the results of the cotton study . Therefore, a 5X saffl ower processing study is not required , because residues are not expected to be found in the processed commodities.Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 4 of 15 An analy tical standard for thifensulfuron methyl is currently available in the National Pesticide Standards Reposito ry (NPSR) . Confined rotational crop studies have previously been submitted. These studies were initially reviewed by the Environmental Fate and Effects Division (EFED) , and were deemed inadequate pending submission of additional data and information to upgrade the acceptability of a greenhouse confined rotational crop study with [triazine - 2 - 14 C] - thifensulfuron methyl. The requested data and information have been submitted , and reviewed by HED. HED concluded that although the data are not fully adequat e, a new confined rotational crop study will not be required because of the nature of the pesticide. It is unlikely that additional ROCs would be found if the study

were repeated. No field rotational crop studies have been submitted for thifensulfuron me thyl, and none are required for this petition . The 45 - day plantback interval (PBI ) on the product label for Harmony® SG is adequate. Regulatory Recommendations and Residue Chemistry Deficiencies Pending submission of a revised Section F, there are no major deficiencies which would preclude the establishment of a permanent tolerance for regional use of thifensulfuron methyl (as Harmony® SG ) on safflower. Provided that the forthcoming human health risk assessment (D361902; W.T. D rew; 29 January 2010 ) does not identify

any issues of concern, the submitted data support a regional tolerance for residues of thifensulfuron methy l, including its metabolites and degradates, in or on safflower seeds, at the level listed below. Compliance with the tolerance level specified below is to be determined by measuring thifensulfuron methyl only . Safflower, seed ................................ ................................ ..... 0.05 ppm The deficienc y noted in this document is presented below . 860.1550 Proposed Tolerances A revised Section F should be submitted to delete the word “combined” from the tolerance expression. Note to RD : According to HED’s Interim Guidance on Tolerance Expressions (S. Knizner, 27 May 2009), the tolerance expression for thifensulfuron methyl cited in 40CFR §180.439[a] shou ld be revised to state: Tolerances are established for residues of thifensulfuron methyl, including its metabolites and degradates, in or on the commodities listed in the table below. Compliance with the tolerance levels specified below is to be determ ined by measuring only thifensulfuron methyl (methyl 3 - [[[[(4 - methoxy - 6 - methyl - 1,3,5 - triazin - 2 - yl)amino]carbonyl]amino] sulfonyl] - 2 - thiophenecarboxylate).Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 5 of 15 Background The chemical structure and nomenclature of thifensulfuron methy l are presented in Tab le 1 , below . The phy sicochemical properties of the technical grade of thifensulfuron methy l are presented in Table 2 , below . TABLE 1 Thifensulfuron Methyl Nom enclature. Chemical structure N N N C H 3

O C H 3 N H N H O

S C O 2 C H 3 S O O Common name Thifensulfuron methyl Molecular formula C 12 H 13 N 5 O 6 S 2 Molecular w eight 387.38 Company experimental name DPX - M6316 IUPAC name Methyl 3 - (4 - methoxy - 6 - methyl - 1,3,5 - triazin - 2 - ylcarbamoylsulfamoyl) thiophene - 2 - carboxylate CAS name M ethyl 3 - [[[[(4 - methoxy - 6 - methyl - 1,3,5 - triazin - 2 - yl)amino]carbonyl]amino] sulfonyl] - 2 - thiophenecarboxylate CAS registry number 792 7 7 - 27 - 3 End - use product (EP) F ield trial s : 75% ai DF , DuPontTM Harmony ® GT XP, EPA Reg istration # 352 - 446 Proposed use : 50% ai SG , DuPontTM Harmony® SG , EPA Registration # 352 - 633 TABLE 2 Physicochem ical Properties of Thifensulfuron Methyl.

Param eter Value Reference Melting point/range ( oC ) 171.1 ± 1.2 M RID # 47138 3 01 ( D 342084; D. Dotson ; 17 April 2008) pH 4.0 Density (g/cm 3 ) 1.58 ± 0.004 Water solubility (g/L at 25oC) pH 5 0.223 pH 7 2.24 pH 9 8.83 Solvent solubility (g/L at 25oC) Acetone - 11.9 Acetonitrile - 7.3 Dichloromethane - 27.5 Ethano l - 0.9 Ethyl acetate - 2.6 Hexane - <0.1 Methanol - 2.6 Xylene - 0.2Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 6 of 15 TABLE 2 Physicochem ical Properties of Thifensulfuron Methyl.

Param eter Value Reference Vapor pressure (25oC) 1.7 x 10 - 8 Pa (1.3 x 10 - 10 mm Hg) Dissociation constant (pK a ) 4.0 Octanol/water partition coefficient (Log [ K OW ] ) pH 5 1.06 pH 7 0.0222 pH 9 0.0078 UV/visible absorption (max, λ) pH <2 224, 250 nm pH 7 233 nm pH >10 234 nm 860.1200 Directions for Use The EP proposed for use on sa fflower is DuPontTM Harmony® SG h erbicide (EPA Reg istration # 352 - 633), an SG formulation containing 50% thifensulfur on methyl as the ai . The proposed use directions for safflower are summarized in Table 3 (below), and were extracted from an undated supplemental label. The proposed use directions are consistent with the information provided in a revised Section B. T ABLE 3 Summary of Proposed Use of Thifensulfuron Methyl on Safflower. Applic ation Timing; Type; and Equip me nt EP [EPA Reg istration # ] Use Rate

(lb ai/A) Max. # of

Uses per Season Max.

Seasonal Use Rate (lb ai/A) PHI

( D ays) Use Directions and

Limitations 2 Post - emergence (up until flower bud initiation) ; b roadcast foliar ; g round or aerial 1 Harmony® SG , 50% ai [352 - 633] 0.014 -

0.019 1 0.019 81 Use limited to North Dakota, South Dakota, Nebraska, Montana (east of Route 87 or east o f I 15), and Wyoming (ea st of I - 25 or north of I - 90 ) . Spray adjuvants may be included with the spray treatment . 3 1. The supplemental label does not specify application spray volumes. The approved label specifies minimum spray volumes of 10 - 25 gallons per acre (GPA) via groun d equipment , and 5 GPA via aerial equipment for most field crops. The field trials w ere conducted in 15 - 19 GPA via ground equipment. 2. The approved label specifies the follow ing rotational crop restrictions: Wheat, barley, oat, triticale, soybeans, and field corn may be replanted anytime after the application of Harmony® SG. Any other crop may be planted 45 days after the application of Harmony® SG. 3. Non - ionic surfactants (NIS s ) may be mixed with the spray mixture at a rate of 2 - 4 p ints per 100 gallons of spray solution (concentration of 0.25 - 0.55% v/v) . The s urfactant product must contain at least 60% NIS , with a hydrophilic/lipophilic balance (HLB) greater than 12. Crop oil concentrate may be used under dry conditions or during cool w eath er. A petroleum - based oil concentrate may be used in place of an NIS at 1 - 2% (v/v). Use an oil adjuvant that contains at least 80% of a high quality, petroleum (mineral) or modified vegetable seed oil w ith at least 15% surfactant emulsifiers.Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 7 of 15 Concl usions : The proposed label directions for Harmony® SG are adequate to allow evaluation of the residue data. Although the submitted magnitude of the residue study for safflower reflects the use of a 75% ai dry flowable (DF) formulation (as opposed to the requested 50 % ai SG formulation), the field trials reflect the proposed use rate , and PHI . 860.1300 Nature of the Residue - Plants Residue Chem istry Mem o D 342084; D. Dotson; 17 April 2008 ( PP# 7F7219) Residue Chem istry Mem o D301509 ; J. Facey; 10 June 20 04 (M etabolism Decision Docum ent) The nature of the residue in plants is adequately understood , based on acceptable studies with wheat, corn and soy

beans. The salient features of these metabolism studies were recently summarized in a r esidue c hemistry s ummary d ocument (D342084 ; D. Dotson; 17 April 2008) . The metabolism of thifensulfuron methyl in tested crops proceeds by hydroly sis of the methyl ester and sulfonyl urea moieties, with some demethylation of the triazine methoxy group. HED has determine d that the ROC in plant commodities is thifensulfuron methyl for the purposes of tolerance expression , and risk assessment. The available plant metabolism studies are adequate to support the requested use on safflower. 860.1300 Nature of the Residue - Livestock Residue Chem istry Mem o D342084; D. Dotson; 17 April 2008 (PP#7F7219) Residue Chem istry Mem o D301509; J. Facey; 10 June 2004 (MetabolismDecision Docum ent) The nature of the residue in livestock is adequately understood , based on the availabl e goat metabolism study . HED has previously concluded in D 342084 that the goat metabolism study is adequate in supporting the registered uses of thifensulfuron methyl residues on cereal grains , an d soy

bean s . This conclusion is based on the low level of transfer of thifensulfuron methyl residues to goat matrices , and the lack of detectable residues in livestock feed items, even at exaggerated application rates. HED also concluded that , because no detectable residues of thifensulfuron methyl were found in poultry feed items, a poultry

metabolism study

is not required. HED has determined that the ROC in livestock commodities is thifensulfuron methyl for the purposes of tolerance expression , and risk assessment. The current petition does not alter HED’s ear lier conclusions regarding livestock metabolism. 860.1340 Residue Analytical Methods Residue Chem istry Mem o D342084; D. Dotson; 17 April 2008 (PP#7F7219) Residue Chem istry Mem o D 311607; S. Ary; 4 January 20 05 Residue Chem istry Mem o D301488 ; S. Ary; 12 August 2004 Residue Chem istry Mem o D301509; J. Facey; 10 June 2004 (MetabolismDecision Docum ent) Enforcement methods: Two HPL C photo - conductivity detection methods (Methods AMR - 646 - 86 and AMR - 761 - 87) are available for enforcing tolerances for resi dues ofThifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 8 of 15 thifensulfuron methyl in cereal grains and straw. For Method AMR - 646 - 86, straw samples are extracted with ethyl acetate, and the extract is partitioned with sodium bicarbonate. The aqueous phase is acidified , and partitioned with dichloromethane. The dichloromethane phase is evaporated to dry

ness , and then reconstituted for analy sis via HPL C with photo - conductivity detection. For Method AMR - 761 - 87, wheat grain is extracted with ethyl acetate, barley grain is extracted with 0.1 M sodium bicarbonate, and straw is extracted with ethyl acetate/HCl (at pH 3) . E xtracts are then analy

zed via HPL C with photo - conductivity detection. A n LC /MS method (DuPont Method 1381) is also available for enforcing tolerances for residues of thifensulfuron methyl in canola, cotton, and flax commodities. For this method, samples are extracted with an acetonitrile/ammonium carbonate buffer solution, and the concentrated residues are reconstituted in methanol for analy sis. I f required, a hexane wash step , or cleanup s tep using a strong anion exchange solid phase extraction ( SPE ) column , may be incorporated. Analy sis is performed via column - switching LC . Extracts in methanol are applied to a size exclusion chromatography column, and the eluate is diverted onto a rever sed phase XDB - C 8 column for MS analy sis. The validated L OQ was 0.020 ppm. This method may also be used for enforcing tolerances in corn grain, sorghum grain , and soy bean seed s . Data collection method: Samples collected from the safflower field trial and processing studies were analy

zed for residues of thifensulfuron methyl using an HPL C photo - conductivity method (DuPont Method AMR - 973 - 87). The method was adequate for data collection , based on acceptable method validation and concurrent method recove ries. Fortification levels were adequate to bracket residues found in treated samples. The lowest limit of method validation (LLMV) was 0.05 0 ppm in each matrix. T he calculated LOQ s w ere 0.027 ppm in safflower seed s , 0.039 ppm in meal , and 0.0068 ppm in oil. The calculated limit s of detection (LOD s ) w ere 0.009 ppm in seed s , 0.013 ppm in meal , and 0.0023 ppm in oil. Conclusions : The available residue analy tical method data are adequate to satisfy data requirements. The existing tolerance enforcement methods, AMR - 646 - 86, AMR - 761 - 87, and DuPont Method 1381, are adequate to enforce the proposed tolerance in safflower seeds , and DuPont Method AMR - 973 - 87 is adequate for data collection purposes. 860.1360 Multiresidue Methods Residue Chem istry Mem o D3 01488; S. Ary; 12 August 2004 Residue Chem istry Mem o CB 2354; C. Deyrup; 10 March 19 88 The FDA ’s PESTDATA database , dated June 20 05 ( PAM Volume I

, Appendix I ) does not contain any

information regarding the recovery of thifensulfuron methyl using multire sidue methods. Data investigating the behavior of thifensulfuron methy l using the FDA Multiresidue Methods have been submitted by the petitioner (MRI D # 40429701). Because thifensulfuron methyl is thermally

labile, only

Multiresi due Protocol A was investi gated. I t was determined that thifensulfuron methyl does not give a sufficient response on the required HPL C sy stem ( D301488; S. Ary ; 12 August 2004 ). The available data indicate that residues of thifensulfuron methyl are not recovered by the FDA multire sidue methods.Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 9 of 15 860.1380 Storage Stability Residue Chem istry Mem o s D330702 and D330813; S. Hum me l; 8 August 20 06 Residue Chem istry Mem o D301488; S. Ary; 12 August 2004 R esidue Chem istry Mem o PP#8G3602; R. Loranger; 18 May 1988 R esidue Chem istry Mem o PP#6F3431; C. Deyrup; 24 Decem ber 1987 The storage durations and conditions of commodity samples collected from the safflower field trial and processing studies are listed in Table 4 , below . To validate sample storage conditions and durations , a conc urrent storage stability study was conducted . Control samples of safflower seed s , meal and oil were fortified with thifensulfuron methyl at 0.10 ppm , followed by frozen storage of the fortified samples for the duration of the analy sis of the field trial s amples. At the end of the analy

tical phase, the storage stability samples were analy

zed for residues of thifensulfuron methyl. The overall average corrected recover ies w ere 9 2 % fr om safflower seed s, 97% f r om safflower meal, and 108% fr om safflower oil. A lthough there w as no zero - day analy sis of fortified sample s , the storage stability data are adequate , and support the storage conditions and durations incurred in the field trial and processing studies. TABLE 4 Summary of Storage Conditions and Duratio ns of Sam ples from the Safflower Field Trial

and Processing Studies. Matrix Storage

Tem perature (°C) Actual Storage Duration ( D ays) Interval of Dem onstrated Storage Stability ( D ays) Safflower seed s - 26 to - 14 608 - 632 631 Safflower meal 567 584 Saf flower oil 561 588 Additional storage stability data are available from previous submissions. These data indicat e that thifensulfuron methyl is stable under frozen storage conditions for intervals of at least 4 months in corn stover and soy bean seeds, 14 months in cotton seed s and cotton gin by products, 24 months in corn grain and forage , and wheat straw, and 36 months in wheat grain. Conclusion s : The available storage stability data adequately

support the sample storage durations incurred in the s afflower field trial and processing studies . No storage stability corrections need to be applied to the safflower field trial and processing study results. 860.1400 Water, Fish, and Irrigated Crops There are no proposed or registered uses that are r elevant to this guideline topic. 860.1460 Food Handling There are no proposed or registered uses that are relevant to this guideline topic.Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 10 of 15 860.1480 Meat, Milk, Poultry, and Eggs According to OPPTS Residue Chemistry Test Guideline 860.1000 , Table 1 Feedstuffs ( June 200 8 ), safflower meal is the only animal feed stuff associated with the current petition. Safflower meal may

constitute up to 5% of beef cattle diet, 10% of dairy cattle diet, 25% of poultry diet, and 5% of swine diet. Inconsideration o f the proposed regional use of thifensulfuron methyl on safflower , and the observed residue s of < 0.050 ppm in safflower meal, the potential contribution to the maximum reasonably balanced dietary

burdens of livestock is negligible. Therefore, tol erances i n meat, milk, poultry and eggs are not required for this petition. 860.1500 Crop Field Trials DER for MRID # 47641801 (CFTs with S afflower ) Three safflower field trials were conducted in Zones 5 (SD) and 7 (ND; 2 trials) during the 2000 growing seaso n. At each site a 75 % ai DF formulation of thifensulfuron methyl was applied to safflower as a single broadcast foliar application, either 81 or 36 day s prior to harvest, at rates of 0.0176 - 0.0187 lb ai/A ( roughly 1X the proposed rate). Applications were made using ground equipment , in spray volumes of 15 - 19 GP A, and included the use of an NI S adjuvant . Duplicate control and treated samples of safflower were harvested 81 day s after treatment (DAT) from two ND field trials , and 36 DAT from the SD field tr ial. Samples of safflower seeds were analy zed for residues of thifensulfuron methyl using an adequate HPLC photo - conductivity method (DuPont Method AMR - 973 - 87). The method was adequate for data collection , based on acceptable method validation and conc urrent method recoveries. Fortification levels were adequate to bracket residues found in treated samples. The LLM V was 0.05 0 ppm, while the calculated LOQ and LOD were 0.027 and 0.009 ppm, respectively . Safflower seed samples were stored for up to 63 2 day s prior to analy sis. The sample storage conditions and durations for safflower seeds are supported by adequate concurrent storage stability

data. The results indicate that following one broadcast foliar application of thifensulfuron methyl ( 75% ai DF) to safflower , at rates of 0.0176 - 0.0187 lb ai/A, residues in safflower seeds were < 0.050 ppm for all 6 samples harvested at either 81 DAT or 36 DAT (see Table 5 , below ). Although the treatment rate at the SD trial was under - applied by 7% , and samples were harvested more than 40 day s earlier than the other field trials, this application error will have no impact on the adequacy

of the field trial s , as all residues were < 0.050 ppm . A residue decline study was not conducted.Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 11 of 15 TABLE 5 Summary of Resid ue Data fromSafflower Field Trials with Thifensulfuron Methyl. Com mo dity Total Use Rate

(lb ai/A) PHI

( D ays) Residue Levels (ppm )

n Min. Max. HAF T* Median Mean Std. Dev . Safflower Seed 0.0176 - 0.0187 36 - 81 6 <0.05 <0.05 < 0.05 < 0.05 < 0.05 0 * HAFT = Highest Average Field T rial result. Conclusions: The residue data for safflower seeds are adequate to fulfill data requirement s for the proposed use . Although the field trials were conducted with a 75% ai DF formulation of thifensulfuron methyl, the number and location of the field trials support the requested regional use of Harmony® SG on safflower. The data reflect the proposed use pattern (maximum use rate of 0.019 lb ai/A, a PHI of 81 day s, and use of an NI S in the spray mixture). HED conclu des that the propose d tolerance of 0.05 ppm is a ppropri ate. 860.1520 Processed Food and Feed DER for MRID # 47641801 ( PF F from S afflower Seeds ) To generate samples to be used for processing, one trial was conducted in ND during the 2000 growing seaso n. Safflower seeds were harvested 81 day s following a single broadcast foliar application of the 75 % ai DF formulation, at a rate of 0.0186 lb ai/A ( roughly 1X the proposed rate). The application was made using ground equipment in a spray volume of 15 GP A , and included the use of an NI S . The safflower seed samples were processed into meal and refined oil using simulated commercial practices. Samples of safflower seed, meal and refined oil were analy zed for residues of thifensulfuron methyl using an ad equate HPLC photo - conductivity method (DuPont Method AMR - 973 - 87). The method was adequate for data collection , based on acceptable method validation and concurrent method recoveries. Fortification levels were adequate to bracket residues found in treated samples. The LLM V in each matrix was 0.050 ppm. The calculated LOQ s we re 0.027 ppm in seed, 0.039 ppm in meal , and 0.0068 ppm in oil, while the calculated LOD s we re 0.009 ppm in seed, 0.013 ppm in meal , and 0.0023 ppm in oil. Samples of safflower see d were stored frozen for up to 608 day s , while processed samples of meal and oil were stored frozen for up to 567 and 561 day s, respectively , prior to analy sis. The storage durations are supported by adequate storage stability data , which were generated c oncurrently

with the safflower field trial and processing studies. R esidues of thifensulfuron methyl were below the L LM V (< 0.050 ppm ) in safflower seed RAC samples harvested 81 day s after treatment at a rate of 0.0186 lb ai/A ( 1X the field trial application rate ). Following processing, residues of thifensulfuron methyl were < 0.050 ppm in safflower meal and refined oil proces sed from treated safflower seed. P rocessing factors could not be calculated because re sidues were below the L LM V in both the RAC and the processed fraction s . The theoretical processing factors for safflower meal and oil are 9. 1X and 3.3 X , respectively ( OPPTS Residue Chemistry Test Guideline 860. 1520 , Table 3).Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 12 of 15 Conclusions: The submitte d safflower processing study showed that residues of thifensulfuron methyl were < 0.050 ppm in safflower meal , and refined oil , processed from safflower seeds treated at 1X . Thifensulfuron methyl is not expected to concentrate in saff lower oil because it has a very

low octanol/w ater partition coefficient (Log K OW = 0.027). I t has been shown in the cotton processing study (MRI D # 45098405) that , after treatment at an exaggerated rate of 0.094 lb ai/A ( roughly 4 X the normal use rate of 0 .025 lb ai/A) , applied one day after planting , with a 133 - day

PHI , residues of thifensulfuron methyl were non - detectable ( < 0.006 ppm) in undelinted cotton seed s . As with cotton, the PHIfor safflower following treatment with thifensulfuron methyl is relat ively long (81 day s). Cotton seeds, like safflower seeds, may be processed into oil or meal, and as such, thifensulfuron methyl is not expected to concentrate in safflower processed food/feed items. Also, the requirement for processing studies in canola and flax has previously

been waived, based on the results of the cotton study . Therefore, a 5X processing study

is not required in safflower. 860.1650 Submittal of Analytical Reference Standards An analy tical standard for thife nsulfuron methyl is currently available in the NPSR , via personal communication with Dallas Wright , of the Biological and Economic Analy sis Division’s Analy

tical Chemistry

Branch ( BEAD /ACB ) , on 27 July 20 09 . Analy

tical reference standards should be replen ished as requested by the Repository . The reference standards should be sent to the AC B , which is located at Fort Meade, to the attention of Theresa Cole at the following address: USEPA National Pesticide Standards Repository /Analy tical Chemistry

Branch/OPP 701 Mapes Road Fort George G. Meade, MD 20755 - 5350 (Note that the mail will be returned if the extended zip code is not used.) 860.1850 Confined Accumulation in Rotational Crops 860.1900 Field Accumulation in Rotational Crops Residue Chem ist ry Mem o D342084; D. Dotson; 17 April 2008 (PP#7F7219) Confined rotational crop studies have previously been submitted. These studies were initially reviewed by

EFED , and were deemed inadequate pending submission of additional data and information to upg rade the acceptability of a greenhouse confined rotational crop study with [triazine - 2 - 14 C] - thifensulfuron methyl. The requested data and information have been submitted and reviewed by

HED. HED concluded that although the data are not fully adequate, a new confined rotational crop study will not be required because of the nature of the pesticide. It is unlikely that additional ROCs would be found if the study were repeated. No field rotationalThifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 13 of 15 crop studies have been submitted for thifensulfuron methyl, and none are required for this petition . The 45 - day PBI on the product label for Harmony® SG is adequate. 860.1550 Proposed Tolerances HED has previously determined that the ROC in plant commodities is thifensulfuron methyl for the purposes of tole rance expression , and risk assessment. Permanent tolerances are established for thifensulfuron methyl in/on barley , canola, corn, cotton, flax, oat, rice, sorghum, soy bean and wheat commodities , at levels ranging from 0.02 to 2.5 ppm ( 40 CFR §180.439[ a ] ) . The subject petition proposes a tolerance for “ combined ” residues of the herbicide thifensulfuron methyl in/ on safflower, seed (RAC) at 0.05 ppm. A revised Section F should be submitted to delete the word “combined” from the tolerance expression. The safflower field trial data are adequate to support a regional tolerance of 0.05 ppm in safflower seeds grown in North Dakota, South Dakota, Nebraska, Montana (east of Route 87 or east o f I - 15), and Wyoming (east of I - 25 or north of I - 90 ) . All safflower se eds bore residues below the LLM V (< 0.050 ppm) following application of a 75 % ai DF formulation according to the proposed rate and PHI . No tolerances are required for residues of thifensulfuron methyl in animal commodities , n or in rotational crops , for the purpose s of this petition . A summary

of the proposed and recommended tolerance s is presented in Table 6 , below . There are no established or proposed Codex Maximum Residue L imits (MRL s) for residues of thifensulfuron methyl. Canada and Mexico have established MRL s for thifensulfuron methyl i n several plant commodities. The ROC s in Canada, Mexico and the US are harmonized. However, no Canadian or Mexican MRL s for thifensulfuron methyl have been proposed or established in safflower seed . An Internat ional Residue L imit Status sheet is a ppend ed to this document . TABLE 6 Tolerance Sum ma ry for Thifensulfuron Methyl. Com mo dity Proposed Tolerance (ppm ) Recom me nded

Tolerance (ppm ) Com me nts; Correct Commodity Definition Safflower , s eed 0.05 0.05Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 14 of 15 References PP # 7F7219 Label Amendments and Petition for Tolerances on W heat Forage and Hay, Oat Forage and Hay, and Barley Hay. Summary of Analytical Chemistry and Residue Data. ; D 342084; D. Dotson ; 17 April 20 08 . Thifensulfuron Methyl. Addition of Uses on Rice and Sorghum (PRIA R19 - 352 - 611; PP#4F6889). Summary of Analytical Chemistry and Residue Data. ; D330702 and D330813; S. Hummel ; 8 August 20 06 . Thifensulfuron Methyl. HED’s Response to E.I. du Pont de Nemours and Company’s Comments to the “Summary of Residue Chemistry Data Evaluation Records for the Establishment of Tolerances for New Uses of Thifensulfuron Methyl on Canola, Flax, and Cotton.” ; D311607 ; S. Ary ; 4 January 20 05 . Thifensulfuron Methyl. Summary of Residue Chemistry Data Evaluation Records for the Establishment of Tolerances for New Uses of Thifensulfuron Methyl on Canola, Flax, and Cotton. ; D301488 ; S. Ary ; 12 August 20 04 . Thifensulfuron Methyl. Meeting Report of the Metabolism Assessment Review Committee Document. TXR Number 0052419 ; D301509 ; J. Facey ; 10 June 20 04 . PP#8G3602, 352 - EUP -RUL. DPX - M316 (Pinnacle) on Soybeans. Evaluation of Analytical Method and Residue Data ; R. L oranger ; 1 8 May 19 88 . PP #6F3431. Response ( 2 December 19 87) by E.I. Du Pont de Nemours &Co. to the Need for Testing DPX

-H6573 (HarmonyTM) with Multiresidue Protocols . (RCB #2 2354 ) ; CB2354 ; C. Dey

rup ; 10 March 19 8 8 . PP #6F3431. Response ( 14 September 19 87) by E.I. Du Pont de Nemours &Co. to the D ata Gaps I

dentified in the Prod

uct Chemistry Chapter and Residue Chemistry Chapter of the 2/87 Harmony (DPX

- M6316) Registration Standard. (RCB #2825) ; C. Dey rup ; 24 December 19 87 .Thifensulfuron Methyl Summary of Analytical Chemistry and Residue Data DP Barcode D361945

Page 15 of 15 Appendi x 1 - International Residue Limit Status Sheet



## INTERNATIONAL RESIDUE LIMIT STATUS CAS Nam e: 3 - [[[[(4 - methoxy - 6 - methyl - 1,3,5 - triazin - 2 - yl) amino]carbonyl]amino] sulfonyl] - 2 - thiophenecarboxylic acid Com mo n Nam e: Thifensulfuron methyl X Proposed tolerance

⁮ Reevaluated tolerance ⁮ Other Date: 27 July 2009 Codex Status (Maximum Residue Limits) U S Tolerances X No Codex proposal step 6 or above □ No Codex proposal step 6 or above for the crops requested Petition Number: 9F7523 DP Barcode : D 361945 Othe r Identifier: PC Code 128845 Residue definition (step 8/CXL): Reviewer/Branch: William T. Drew /RAB2 Residue definition: Thifensulfuron methyl Crop (s) MRL (mg/kg) Crop Tolerance (ppm) Safflower, seed 0.05

Limits for Canada L imits for Mexico ⁮ No Limits X No Limits for the crops requested ⁮ No Limits X No Limits for the crops requested Residue definition: M ethyl - 3 - [[[[(4 - methoxy - 6 - methyl 1,3,5 - triazin - 2 - yl)amino]carbonyl]amino]sulfonyl] - 2 - thiophenecarboxylate Residue definition: T hif ensu lfron methyl Crop(s) MRL (mg/kg) Crop(s) MRL (mg/kg)

Notes and / or sp ecial i nstructions: per S teve Funk, 27 July 2009.