Page 1 of 15

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF

CHEMICAL SAFETY AND

 POLLUTION PREVENTION

MEMORANDUM

Date: 23-JAN-2014

Subject: Saflufenacil in/on Rice and Crayfish. Summary of Analytical Chemistry and 

Residue Data.

PC Code: 118203 DP Barcodes: D407976 & D409043

Decision Nos.: 472866 & 473447 Registration No: 7969-278

Petition No.: 2F8129 Regulatory Action: Sec. 3 Registration

Risk Assessment Type: NA Case No.: 7277

TXR No.: NA CAS No.: 372137-35-4

MRID Nos.: 48945803, 4894580304, 

49004101, & 49004102

40 CFR: §180.649

From: George F. Kramer, Ph.D., Senior Chemist

Risk Assessment Branch 1 (RAB1)

Health Effects Division (HED) (7509P)

Through: Charles W. Smith III, Branch Chief

RAB1, HED (7509P)

To: Kathryn Montague/Bethany Benbow, PM Team 23

Registration Division (RD; 7505P)

Executive Summary

Saflufenacil (BAS 800 H) is a broad-spectrum herbicide developed by BASF. It belongs to the 

herbicide mode-of-action Group 14 (cell membrane disruptors). Saflufenacil acts through the 

inhibition of protoporphyrinogen oxidase (PPO), resulting in cell membrane damage and 

subsequent plant death. Sharpen®Powered by Kixor Herbicide (EPA Reg. No. 7969-278), a 

2.85 lb ai/gal suspension-concentrate (SC) formulation, is currently registered for use on legume 

vegetables (Crop Group 06), the foliage of legume vegetables (Crop Group 07), cereal grains 

(Crop Group 15, pre-plant/pre-emergence application only), the forage, fodder, and straw of 

cereal grains (Crop Group 16, pre-plant/pre-emergence application only), cotton, and sunflower. 

BASF has submitted a proposal to allow post-emergence application of saflufenacil to rice and to 

permit crayfish and fish to be grown in the treated rice fields. 

Sharpen®is proposed for up to two spray applications with a total maximum application rate of 

0.135 lb ai/A, with a maximum of 0.045 lb ai/A applied post-emergence between the 2-leaf stage 

and internode elongation. Applications may be made using ground or aerial equipment, and use 

of an adjuvant is required.
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 2 of 15

BASF has petitioned for the establishment of permanent tolerances under 40 CFR 

§180.649(a)(1) for saflufenacil, including its metabolites and degradates, in or on the raw 

agricultural commodities (RACs) listed below. Compliance with the tolerance levels specified 

below is to be determined by measuring only the sum of saflufenacil, 2-chloro-5-[3,6-dihydro-3-

methyl-2,6-dioxo-4-(trifluoromethyl)-1(2H)-pyrimidinyl]-4-fluoro-N-[[methyl(1-

methylethyl)amino]sulfonyl]benzamide, and its metabolites N-[2-chloro-5-(2,6-dioxo-4-

(trifluoromethyl)-3,6-dihydro-1(2H)-pyrimidinyl)-4-fluorobenzoyl]-N'-isopropylsulfamide and 

N-[4-chloro-2-fluoro-5-({[(isopropylamino)sulfonyl]amino}carbonyl)phenyl]urea, calculated as 

the stoichiometric equivalent of saflufenacil in/on the following plant commodities:

Grain, cereal, forage, fodder and straw group 

16 (except rice straw) 0.1 ppm

Rice, straw 0.30 ppm

BASF has also petitioned for the establishment of permanent tolerances under 40 CFR 

§180.649(a)(2) for saflufenacil, including its metabolites and degradates, in or on the agricultural 

commodities listed below. Compliance with the tolerance levels specified below is to be 

determined by measuring only saflufenacil, 2-chloro-5-[3,6-dihydro-3-methyl-2,6-dioxo-4-

(trifluoromethyl)-1(2H)-pyrimidinyl]-4-fluoro-N-[[methyl(1-

methylethyl)amino]sulfonyl]benzamide, in/on the following commodities:

Fish-freshwater finfish 0.01 ppm

Fish-shellfish, crustacean 0.01 ppm

The previously-submitted metabolism data for corn, soybean, and tomato were adequate to 

elucidate the nature of the residue in plants resulting from pre-plant/pre-emergence application. 

The HED Residues of Concern Knowledgebase Subcommittee (ROCKS) determined that 

residues of concern for the tolerance expression and risk assessment consist of saflufenacil, 

M800H11, and M800H35 (Memo, B. Daiss, 1/6/09; D359645). Subsequently, the petitioner 

submitted a rice metabolism study following post-emergence foliar application of saflufenacil. 

The combined residues of saflufenacil, M800H11, and M800H35 (the current residues of 

concern for the tolerance expression and risk assessment) in rice forage were 71-89% of the total 

radioactive residue (TRR). The only other major metabolite was M800H02, which accounted for 

4-16% of the TRR in forage. In rice grain, the combined residues of saflufenacil and all 

metabolites was <10% of the TRR (≤0.01 ppm). HED thus concludes that current tolerance 

expression adequately accounts for the residues of concern following post-emergence foliar 

application to rice. Additional metabolism data may be required to support foliar application to 

non-grass crops. 

The nature of the residue in livestock is adequately understood based on acceptable metabolism 

studies conducted on lactating goats and laying hens. Rice straw is not a regulated commodity. 

Rice grain is thus the only livestock feedstuff associated with the proposed use. As the existing 

tolerance for residues in/on rice grain (as a member of cereal grains Crop Group 15) is 

unaffected by the proposed new use pattern, no changes in the existing tolerances for livestock 

commodities are needed.

The petitioner has submitted two liquid chromatography/mass spectroscopy/mass spectroscopy 

(LC-MS/MS) analytical methods for the determination of residues of the parent and its 

metabolites in/on plant and livestock commodities. BASF Method D0603/02 was developed for 

determination of residues of saflufenacil and its metabolites M800H11 and M800H35 in 
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 3 of 15

different plant matrices using LC-MS/MS. The limit of quantitation (LOQ) was 0.01 ppm for 

each analyte in food matrices (human consumption) and 0.025 ppm for each analyte in feed 

matrices (livestock consumption). This method was used as the data-collection method in the 

analysis of samples for residues of concern from rice studies submitted with the current petition 

(studies included adequate method validation data). BASF analytical Method No. L0073/01 is 

the current enforcement method for determination of saflufenacil in livestock matrices using LCMS/MS. Samples of crayfish were analyzed with a simplified version of this method which 

omitted the clean-up step. The method was adequate for data collection based on acceptable 

method validation and concurrent recovery data. Apparent residues of saflufenacil were below 

the LOQ in/on all samples of untreated water and crayfish. BASF Method L0073/01 is thus 

suitable as an enforcement method for crayfish.

The actual analysis dates of the samples from the submitted magnitude of residue study in 

freshwater crayfish were not provided. Based on the sample collection dates and the final report 

date, the estimated storage duration for frozen samples is <125 days. No supporting storage 

stability data were submitted. Sample analysis dates are required to determine the duration of 

storage. Ruminant storage stability data are available which show that saflufenacil is stable for 

up to 35 days in ruminant matrices (47128015.der.doc). These data can be translated to crayfish. 

However, if crayfish samples were stored for more than 35 days, then storage stability data may 

be required for saflufenacil in crayfish. Provided issues related to storage stability are resolved, 

the submitted magnitude of saflufenacil residue study in freshwater crayfish will support the 

proposed tolerance for residues in/on fish-shellfish, crustacean. In addition, the crayfish 

magnitude of saflufenacil residue data can be translated to support the proposed tolerance for 

residues in/on fish-freshwater finfish. 

The submitted rice field trial data are adequate to fulfill data requirements. Following two 

broadcast applications of the 342 g ai/L SC formulation of saflufenacil at 0.131-0.139 lb ai/A, 

combined residues (and per-trial averages) of saflufenacil, M800H11, and M800H35 in/on rice 

grain harvested at a 54- to 103-day PHI were all <LOQ (<0.03 ppm). The available data will 

thus support the proposed use pattern. Since the existing tolerance of 0.03 ppm for residues 

in/on rice grain (as a member of cereal grains Crop Group 15) is supported by the residue data 

reflecting the post-emergent use pattern, no changes in the existing tolerances for Crop Group 15 

are needed. However, a tolerance is not required for rice straw since it is not a regulated 

commodity. A revised Section F is requested (see below).

The submitted rice processing data are adequate to fulfill data requirements. As the residues in 

the RAC were <LOQ after treatment at a 5X rate, a separate tolerance for hulls and bran will not 

be required.

The previously submitted confined and field rotational crop data are adequate to satisfy data 

requirements for application rates up to 0.137 lb ai/A (1X). The available data indicate that 

residues of saflufenacil and its metabolites M800H11 and M800H35 were each <LOQ in/on all 

rotational crop matrices at a 120-day PBI. These data support the labeled rotational crop 

restriction of 4 months for all non-labeled crops. 

Regulatory Recommendations and Residue Chemistry Deficiencies

Pending submission of a revised Section F (see requirements under Proposed Tolerances) and 

issues related to storage stability in crayfish are resolved (see requirements under Storage 
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 4 of 15

Stability), there are no residue chemistry issues that would preclude granting the following 

permanent tolerances for residues of saflufenacil under 40 CFR §180.649(a)(2):

Fish-freshwater finfish 0.01

Fish-shellfish, crustacean 0.01

860.1380 Storage Stability

Actual analysis dates of the samples from the submitted magnitude of residue study in 

freshwater crayfish were not provided. No supporting storage stability data were 

submitted. Sample analysis dates are required to determine the duration of storage. 

Ruminant storage stability data are available which show that saflufenacil is stable for up 

to 35 days in ruminant matrices (47128015.der.doc). These data can be translated to 

crayfish. However, if crayfish samples were stored for more than 35 days, then storage 

stability data may be required for saflufenacil in crayfish.

860.1550 Proposed Tolerances

The petitioner is requested to submit a revised Section F specifying the tolerances 

summarized above and in Table 7.

A human-health risk assessment is forthcoming in a separate document (DP# 405506).

Background

Saflufenacil is a broad-spectrum herbicide developed by BASF. It belongs to the herbicide 

mode-of-action Group 14 (cell membrane disruptors). Saflufenacil acts through the inhibition of 

PPO, resulting in cell membrane damage and subsequent plant death. Susceptible weeds develop 

symptoms within hours of application under active growing conditions. Plant death occurs 

within 3-5 days depending upon growing conditions. The chemical structure and nomenclature 

of saflufenacil and its metabolites M800H11 and M800H35, and the physicochemical properties 

of the technical grade of saflufenacil are presented in Tables 1 and 2.

Table 1. Saflufenacil and Metabolite Nomenclature.

Chemical Structure

Common name Saflufenacil

Company experimental name BAS 800 H (synonyms: AC 433 379, BASF Reg. No. 4054449)

IUPAC name N'-[2-chloro-4-fluoro-5-(3-methyl-2,6-dioxo-4-(trifluoromethyl)-3,6-dihydro-1(2H)-

pyrimidinyl)benzoyl]-N-isopropyl-N-methylsulfamide

CAS name 2-chloro-5-[3,6-dihydro-3-methyl-2,6-dioxo-4-(trifluoromethyl)-1(2H)-pyrimidinyl]-4-

fluoro-N-[[methyl(1-methylethyl)amino]sulfonyl]benzamide

CAS registry number 372137-35-4

F Cl

N

N

O

O

CH3

F

F

F

O

N

H

S

N

O

O

CH3

CH3

CH3
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 5 of 15

Table 1. Saflufenacil and Metabolite Nomenclature.

End-use product (EP) Sharpen®Powered by Kixor Herbicide (EPA Reg. No. 7969-278) (2.85 lb ai/gal SC 

formulation)

Chemical Structure

Common name M800H11

Chemical name N-[2-chloro-5-(2,6-dioxo-4-(trifluoromethyl)-3,6-dihydro-1(2H)-pyrimidinyl)-4-

fluorobenzoyl]-N'-isopropylsulfamide

Chemical Structure

Common name M800H35

Chemical name N-[4-chloro-2-fluoro-5-({[(isopropylamino)sulfonyl]amino}carbonyl)phenyl]urea

Table 2. Physicochemical Properties of Technical Grade Saflufenacil.

Parameter Value

Melting point Average = 189.9 °C, peak max = 193.4 °C

pH 4.43 of 1% solution at 25 °C

Bulk Density (ambient 

temp.) 0.661 kg/L (free fall), 0.736 kg/L (packed)

Water solubility (20 °C) in g/100 mL:

0.0025 in water (pH = 5); 0.0014 in pH 4 buffer; 0.21 in pH 7 buffer; not determined due to 

degradation in pH 9 buffer

Solvent solubility (20 °C) in g/100 mL: 

19.4 acetonitrile; 24.4 dichloromethane; 55.4 N,N-dimethylformamide; 27.5 acetone; 6.55 ethyl 

acetate; 36.2 tetrahydrofuran; 35.0 butyrolactone; 2.98 methanol; 0.25 isopropyl alcohol;

0.23 toluene; <0.01 1-octanol; <0.005 n-heptane

Vapor pressure at 20/25 °C 20 °C = 4.5 x 10-15 Pa

25 °C = 2.0 x 10-15 Pa

Dissociation constant (pKa) 4.41

Octanol/water partition 

coefficient Mean Log Pow = 2.6 (Pow = 368.3)

UV/visible absorption 

spectrum

wavelength maximum: λmax = 271.6 nm

extinction coefficient: ε = 9709 L/mol-cm

Reference: BASF Registration Document Number (DocID) 2005/1026464.

860.1200 Directions for Use

BASF has submitted draft labels dated 12/17/12 for the 2.85 lb ai/gal SC formulation (Sharpen®

Powered by Kixor Herbicide (EPA Reg. No. 7969-278). Information pertaining to the proposed 

end-use product is listed in Table 3. A summary of the proposed use patterns is detailed in Table 

4. 

F Cl

N

N

H

O

O

F

F

F

O

N

H

S

N

H

O

O

CH3

CH3

F Cl

N

H

O

O

N

H

S

N

H

O

O

CH3

CH3

H2N
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 6 of 15

Table 3. Summary of Proposed End-Use Product.

Trade Name

Reg. 

No.

ai (% of 

formulation)

Formulation 

Type Target Crop

Target 

Pests Label Date

Sharpen®

Powered by 

Kixor 

Herbicide

7969-

278 29.74 SC Rice Broadleaf weeds

Draft label 

submitted 

12/17/12

Table 4. Summary of Directions for Use of Saflufenacil.

Applic. Timing, 

Type, and Equip. Formulation

App. rate

(lb ai/acre)

Max. No. 

App. per 

Season

Max. Seasonal 

App. Rate

(lb ai/acre)

PHI

(days) Use Directions and Limitations

Rice

Ground, Air

Sharpen®

Powered by 

Kixor Herbicide

0.045-0.090 2 0.135 -

- A maximum of 0.045 lb 

ai/A applied post-emergence 

between the 2-leaf stage and 

internode elongation.

- Minimum retreatment 

interval (RTI) = 14 days.

- May be applied to fields 

used for crayfish and fish 

production.

- May not be applied to fields 

used for mollusc production.

- Flood water from treated 

fields must be held at least 7 

days prior to release.

Note: A crop-oil concentrate is required for optimum activity.

Table 5. Rotational Crop PBIs for Saflufenacil (from Master Label, no changes proposed).

Crop

PBI (months)

Application rate (lb ai/acre)

0.0225 0.045 0.067 0.089 0.112 0.134

Corn 0 0 0 0 0 0

Corn, sweet 0.5 1 2 3 4 4

Sorghum 0 0 0 0 1 1

Small Grains 0 0 0 0 3 3

Chickpea, Field pea, 

Edible pea 0 0 3 3 6 6

Lentil 1 2 3 4 6 9

Soybean 1 2 3 4 6 9

Cotton 1.5 3 4 6 6 9

Other Crops 4 5 6 7 8 9

Conclusions: The submitted use directions for Sharpen®are adequate to allow evaluation of the 

residue data relative to the proposed uses. 

860.1300 Nature of the Residue - Plants

DER Reference List 48849001.der.doc

The previously-submitted metabolism data for corn, soybean, and tomato were adequate to 

elucidate the nature of the residue in plants resulting from pre-plant/pre-emergence application. 

The main reactions involved in the metabolic pathway of saflufenacil were N-demethylation at 
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 7 of 15

the uracil ring, stepwise degradation (N-dealkylation) of the N-methyl-N-isopropyl group, 

hydrolytic cleavage of the uracil ring generating a urea side chain, and hydroxylation of the 

phenyl ring. The HED ROCKS determined that residues of concern for the tolerance expression 

and risk assessment consist of saflufenacil, M800H11, and M800H35 (Memo, B. Daiss, 1/6/09; 

D359645). The metabolic pathway of radiolabeled saflufenacil in soybean following a lateseason post-emergence treatment follows the same initial pathways, but is not as extensive. No 

new metabolites were observed following post-emergence treatment; however, an additional 

major metabolite (M800H02), that is not included in the tolerance expression, was observed in 

soybean seed. As the structure of M800H02 is closely related to the parent compound and it is 

the precursor of the regulated metabolite M800H11, HED concluded that M800H02 is a residue 

of concern for risk-assessment purposes in seed crops following post-emergence treatment.

BASF Corporation has submitted a study investigating the metabolism of uniformly phenyl ringlabeled [phenyl-U14C]saflufenacil (PH label) and pyrimidine ring-labeled [uracil-4-

14C]saflufenacil (UR label) following early post-emergence foliar application to rice. The 

radiolabeled test substances were applied to rice plants (BBCH growth stages 22-24) grown in 

growth chambers as a single broadcast foliar spray at a nominal rate of 0.089 lb ai/A (2X the 

proposed post-emergence use rate). See Memo, G. Kramer, 4/2/13 (D405746) for the review of 

this study.

Metabolism of saflufenacil in rice (Figure 1, copied without alteration from MRID 48849001) 

proceeds mainly via N-dealkylation reactions at two sites of the molecule and less extensively by 

hydrolysis of the uracil ring or by side chain hydroxylation. N-demethylation on the uracil ring 

yields metabolite M800H02, while N-demethylation at the sulfonamide side chain yields 

metabolites M800H01 and M800H03. Metabolites M800H10 and M800H11 are formed by 

demethylation at both sites, and M800H11 is metabolized to M800H09 by a second Ndealkylation step or to M800H35 by hydrolysis of the uracil ring followed by degradation of the 

side chain or by direct degradation of the uracil ring. M800H35 may also be formed from 

M800H02 by initial hydrolytic cleavage of the uracil moiety to form M800H39 and subsequent 

N-demethylation of this metabolite. Cleavage of the uracil ring generates a carbon chain 

fragment which leads to formation of M800H29 (trifluoroacetic acid), while another hydrolysis 

product of the uracil ring is the methyl ester M800H41 which was identified as an artifact of the 

work-up procedures (most likely resulting from nucleophilic attack of methanol in methanolic 

storage and work-up procedures). Further degradation products of the uracil ring are M800H07 

and M800H39, and hydroxylation of the sulfonamide side chain generates M800H40. 

Metabolism in grain is extensive, as demonstrated by incorporation of radioactivity into 

carbohydrates in both the PH- and UR-labeled matrices.
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 8 of 15

Figure 1. Proposed Metabolic Pathway for Saflufenacil in Rice.

Conclusions: The previously-submitted metabolism data for corn, soybean, and tomato were 

adequate to elucidate the nature of the residue in plants resulting from pre-plant/pre-emergence

application. Subsequently, the petitioner submitted a rice metabolism study following postemergence foliar application of saflufenacil. The combined residues of saflufenacil, M800H11, 

and M800H35 (the current residues of concern for the tolerance expression and risk assessment) 

in rice forage were 71-89% of the total radioactive residue (TRR). The only other major 

metabolite was M800H02, which accounted for 4-16% of the TRR in forage. In rice grain, the 

combined residues of saflufenacil and all metabolites was <10% of the TRR (≤0.01 ppm). HED 

thus concludes that current tolerance expression adequately accounts for the residues of concern 

following post-emergence foliar application to rice. Additional metabolism data may be required 

to support foliar application to non-grass crops.
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 9 of 15

860.1300 Nature of the Residue - Livestock/

860.1480 Meat, Milk, Poultry, and Eggs

The nature of the residue in livestock is adequately understood based on acceptable metabolism 

studies conducted on lactating goats and laying hens. The HED ROCKS determined that 

saflufenacil per se is the only residue of concern for the tolerance expression and risk assessment 

(Memo, B. Daiss, 1/6/09; D359645). Rice straw is not a regulated commodity. Rice grain is 

thus the only livestock feedstuff associated with the proposed use. As the existing tolerance for 

residues in/on rice grain (as a member of cereal grains Crop Group 15) is unaffected by the 

proposed new use pattern, no changes in the existing tolerances for livestock commodities are 

needed.

860.1340 Residue Analytical Methods

BASF Method D0603/02 is the current enforcement method for determination of residues of 

saflufenacil and its metabolites M800H11 and M800H35 in different plant matrices. Residues of 

saflufenacil and its metabolites M800H11 and M800H35 were extracted with methanol:water 

(70:30; v:v). The methanol extract was evaporated and reconstituted in methanol:water (50:50; 

v:v) for LC-MS/MS analysis. Two transitions per analyte were monitored for the quantitation 

and confirmation of saflufenacil, M800H11 and M800H35. The residues of each analyte were 

expressed as parent equivalents using a molecular weight conversion factor (1.0 for saflufenacil, 

1.06 for M800H11, and 1.42 for M800H35). The LOQ was 0.01 ppm for each analyte. The 

limit of detection (LOD) was reported to be 3X the standard deviation (SD) at the LOQ for each 

analyte (0.002-0.003 ppm). The method was adequate for data collection in the rice field trials 

based on acceptable concurrent recovery data. Recoveries were within the acceptable range of 

70-120%. 

BASF analytical Method No. L0073/01 is the current enforcement method for determination of 

saflufenacil in livestock matrices using LC-MS/MS. Livestock tissue samples including bovine 

liver, kidney, fat, muscle, whole milk, skimmed milk, cream, and hen’s egg were extracted with 

acetonitrile. The acetonitrile extract was cleaned-up by liquid/liquid partition using 

dichloromethane and water. The dichloromethane phase was evaporated and reconstituted in 

methanol:water (50:50; v:v) for LC-MS/MS analysis. Two transition ions were monitored (m/z 

of 501 to 459 and 501 to 349) for saflufenacil and either of the transitions can be used for 

quantitation purposes. The LOQ and LOD of the method are 0.01 ppm and 0.000084 ppm, 

respectively. Samples of crayfish were analyzed with a simplified version of this method which 

omitted the clean-up step. For method validation, crayfish tissue samples were fortified with 

saflufenacil at 0.01 and 1.0 ppm. The method was adequate for data collection based on 

acceptable method validation and concurrent recovery data. Apparent residues of saflufenacil 

were below the LOQ in/on all samples of untreated water and crayfish. BASF Method L0073/01 

is thus suitable as an enforcement method for crayfish.

860.1360 Multiresidue Methods (MRM)

Saflufenacil and its metabolites M800H11 and M800H35 were screened through the MRM 

described in the United States Food and Drug Administration (FDA) Pesticide Analytical 

Manual, Vol. I (PAM I). Saflufenacil and the metabolites were tested using procedures outlined 

in Protocols B, C, D, E, and F of the MRM. All Protocols B, C, D, E, and F were found to be 
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 10 of 15

unsuitable for determination of residues of saflufenacil and its metabolites M800H11 and 

M800H35. Since the analytes are not N-methyl-carbamates, naturally fluorescent or substituted 

urea derivatives, the tests using Protocol A and G were not performed.

860.1380 Storage Stability

Rice: Samples were stored frozen (frozen at trial sites; -10 °C at BASF; ~ -26 °C at analytical 

laboratory) from collection to extraction for 243-328 days (8.0-10.8 months) for rice grain. All 

samples were analyzed within 1 day of extraction. Adequate storage stability data are available 

in/on various crop commodities [corn (grain, forage, stover); soybean (seed, forage, hay); orange 

(fruit, pulp, juice, oil); radish (root); grape (raisin); and garbanzo bean (seed)] indicating that 

residues of saflufenacil, M800H11, and M800H35 are stable in/on all tested commodities during 

frozen storage for up to 548 days (MRID No. 47523801). These data are acceptable to support 

the storage conditions and durations of samples from the submitted field trials. 

Crayfish: Actual analysis dates of the samples from the submitted magnitude of residue study 

in freshwater crayfish were not provided. Based on the sample collection dates and the final 

report date, the estimated storage duration for frozen samples is <125 days. No supporting 

storage stability data were submitted. Sample analysis dates are required to determine the 

duration of storage. Ruminant storage stability data are available which show that saflufenacil is 

stable for up to 35 days in ruminant matrices (47128015.der.doc). These data can be translated 

to crayfish. However, if crayfish samples were stored for more than 35 days, then storage 

stability data may be required for saflufenacil in crayfish. 

860.1400 Water, Fish, and Irrigated Crops

Justification to Waive the Data Requirement for Metabolism Studies in Fish (Memo G. Kramer, 4/5/12; D396260).

ChemSAC Decision (3/21/12 meeting): Guideline 860.1400 requires fish metabolism data in a 

predator or bottom-feeder species. In lieu of this study, BASF is requesting that HED accept the 

results of bioaccumulation study in bluegill sunfish conducted for EFED. Since the 

concentration of saflufenacil in the edible tissue of the fish was only 0.35 ppb at the high-dose 

level (10 ug/L), this request is reasonable. However, since we have not received a proposed 

label, granting the waiver should be contingent upon 10 ug/L representing the 1X or an 

exaggerated use rate. The petitioner should note that this waiver applies only to fish metabolism 

studies; a field accumulation study in molluscs will still be required to support the registration of 

the use of saflufenacil in aquatic systems.

DER Reference List 49004101.der.doc

BASF Corporation has submitted a study investigating the magnitude and potential for 

bioaccumulation of saflufenacil residues in freshwater crayfish exposed to floodwater for up to 

28 consecutive days following application of saflufenacil to rice. 

The test substance was formulated as a 342 g ai/L SC and applied to rice grown in an aquatic 

tank containing silt loam soil. One pre-emergence application was made to the soil prior to 

flooding at 0.089 lb ai/A and one post-emergence application was made to the plant canopy 7 

days after flooding (depth of 10 cm) at 0.045 lb ai/A, for a total of 0.13 lb ai/A (1X). 
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 11 of 15

Applications were made at a 54-day re-treatment interval (RTI) using ground equipment. 

Ammonium sulfate and methylated seed oil was added to the spray solutions. Crayfish were 

added to the tanks one day after the last application. Samples of water and crayfish were 

collected 1 hour (0 day) and 1, 3, 7, 14, 21, and 28 days after the introduction of crayfish to the 

tank. 

Following application of saflufenacil to rice at 0.13 lb ai/A (1X), residues of saflufenacil in water 

ranged from 0.0057-0.0199 ppm during the 28-day exposure period; time-weighted mean 

measured concentrations ranged from 0.0130-0.0185 ppm. Maximum residues were observed on 

Sample Day 7. In crayfish tissue, residues of saflufenacil were below the LOQ (<0.01 ppm) in 

all samples. The calculated crayfish bioconcentration factor (BCF) values ranged from <0.26-

<0.37. 

Conclusions: The ChemSAC requested a field accumulation study in molluscs. However, as the 

Sharpen®label prohibits production of molluscs and permits crustacean production, the 

submitted magnitude of saflufenacil residue study in freshwater crayfish is appropriate for this 

proposed use. Additionally, residues of saflufenacil in water following application to rice at 0.13 

lb ai/A (1X) exceeded 10 ug/L, the concentration upon which granting the waiver for fish 

metabolism data was contingent. The proposed tolerance for residues of saflufenacil in fish is 

required as the Sharpen®label specifically allows for application to fields used for commercial 

fish production.

Water and Irrigated Crops: Flood water from treated fields must be held at least 7 days prior to 

release. Following application of saflufenacil to rice at 0.13 lb ai/A (1X), residues of saflufenacil 

in water were 0.0199 ppm 7 days after the last application. The most recent HED risk 

assessment assumed estimated drinking water concentrations of 0.180 ppm (acute) and 0.173 

ppm (chronic; see Memo, G. Kramer, et al., 4/19/11; D380636). As the estimated drinking water 

concentrations are significantly higher than residues in water 7 days following application of 

saflufenacil to rice and there is low potential for bioaccumulation, HED is not concerned with 

residues in water and irrigated crops.

860.1500 Crop Field Trials

DER Reference List 48945803.der.doc 

BASF Crop Protection has submitted field trial data for saflufenacil on rice reflecting residues of 

saflufenacil and metabolites on rice grain and straw. Rice straw is no longer considered to be a 

regulated livestock feedstuff; therefore, only the data for grain are presented herein. Sixteen 

field trials were conducted in the U.S. during the 2011 growing season in the North American 

Free Trade Agreement (NAFTA) Growing Zones 4 (AR, LA, and MO; 11 trials), 5 (MO; 1 trial), 

6 (TX; 2 trials), and 10 (CA; 2 trials). Eight trials were conducted by one Principal Field 

Investigator (PFI) in Zones 4 and 6, and four trials were conducted by another PFI, also in Zones 

4 and 6. Because residues in grain were below the LOQ in/on samples from all trials, except one 

trial which experienced unusual growing conditions (see below), HED has concluded that trial 

independence is not an issue for this study.

Each trial consisted of one untreated plot and one treated plot. At each trial location, the treated 

plot received two broadcast applications of a 342 g ai/L SC formulation of saflufenacil (BAS 800 

04 H). The first application was made at the time of rice seeding (preplant/pre-flood for water-
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 12 of 15

seeded rice [CA trials] and preemergence in dry-seeded rice) at 0.087-0.095 lb ai/A (98-106 g 

ai/ha) followed by a second application made after flooding to rice at the internode elongation 

growth stage at 0.043-0.046 lb ai/A (48-52 g ai/ha), for a total seasonal rate of 0.131-0.139 lb 

ai/A (1X). Applications were made at 39- to 71-day RTIs using ground equipment in spray 

volumes of 17-21 gal/A (159-195 L/ha). A methylated seed oil (MSO) and ammonia sulfate 

(AMS) were added to the spray mixture for each of the applications. Samples of rice grain and 

straw were harvested at 54- to 103-day preharvest intervals (PHIs). At the Yuba City, CA trial 

site (RCN R110020), winds lodged the rice treated plot following draining of the rice paddy, and 

rain refilled the rice paddy so the rice was on the ground and under water for approximately 10 

days prior to harvest. At harvest, the rice was cut and allowed to dry on the bank for a few 

hours, then threshed. This is not typical agronomic or commercial practice. Residues from this 

trial were significantly higher than the other 15 trials and were not included. 

Following two broadcast applications of the 342 g ai/L SC formulation of saflufenacil at 0.131-

0.139 lb ai/A, combined residues (and per-trial averages) of saflufenacil, M800H11, and 

M800H35 in/on rice grain harvested at a 54- to 103-day PHI were all <LOQ (<0.03 ppm).

Residue decline data were not submitted; however, none are required because the pesticide is 

applied before the edible portion of the crop has formed.

Conclusions: The submitted field trial data are adequate to fulfill data requirements. The 

number and locations of the trials are in accordance with OCSPP Guideline 860.1500 (Table 6). 

The available data will thus support the proposed use pattern.

Table 6. Trial Numbers and Geographical Locations.

NAFTA Growing Zones

Rice

Submitted

Requested1

Canada U.S.

4 11 -- 11/7

5 1 -- 1/1

6 2 -- 2/2

10 2 -- 2/2

Total 16 16/12

1

 As per Table 5 of OCSPP 860.1500 for rice. The second number reflects a 25% reduction in the number of trials allowed for 

the crop as a representative commodity in support of a crop group/subgroup tolerance or when application results in no 

quantifiable residues.

860.1520 Processed Food and Feed

DER Reference List 48945804.der.doc 

BASF Crop Protection has submitted a processing study for saflufenacil on rice. In two crop 

field trials conducted in CA and MO in 2011, one untreated and three treated plots were 

established at exaggerated rates [Treatment Plots 2, 3, and 4 corresponding to 1X, 3X, or 5X the 

seasonal field application rate for saflufenacil]. Since rice from Treatment Plot 4 (5X) survived, 

samples from the Treatment Plots 2 and 3 were not further examined. At both trial locations, 

Treatment Plot 4 received two broadcast applications of a 342 g ai/L SC formulation of 

saflufenacil (BAS 800 04 H). The first application was made at the time of rice seeding 

(preplant/pre-flood for water-seeded rice [CA trial] and preemergence in dry-seeded rice [MO 

trial]) at 0.450-0.457 lb ai/A (504-512 g ai/ha) followed by a second application made after 
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 13 of 15

flooding to rice at the internode elongation growth stage at 0.220-0.223 lb ai/A (247-250 g ai/ha), 

for a total seasonal rate of 0.670-0.679 lb ai/A (5X). Applications were made at 49- to 60-day 

RTIs using ground equipment in spray volumes of 17.2-20.0 gal/A (161-187 L/ha) and included 

a MSO and AMS at both trial sites. Samples of rice grain were harvested at maturity [PHIs of 

84-103 days]. Rice grain samples were stored at GLP Technologies (Navasota, TX) and held 

until analysis of the RAC samples. 

Following two broadcast applications of the 342 g ai/L SC formulation of saflufenacil at a rate of 

0.670-679 lb ai/A (751-761 g ai/ha), combined residues (and per-trial averages) of saflufenacil, 

M800H11, and M800H35 in/on rice grain harvested at a 84- to 103-day PHI were all <LOQ 

(<0.03 ppm).

As the RAC grain samples were found to contain no residues greater than the LOQ, processing 

was not performed on the bulk samples. Processing factors were thus not calculated in this 

study. The maximum theoretical concentration factors for rice are 5.0X for hulls and 7.7X for 

bran (based separation of components; OCSPP 860.1520, Table 3).

Conclusions: The submitted rice processing data are adequate to fulfill data requirements. As 

the residues in the RAC were <LOQ after treatment at a 5X rate, a separate tolerance for hulls 

and bran will not be required.

860.1650 Submittal of Analytical Reference Standards

Analytical standards of saflufenacil (expiration date: 5/1/14), M800H11 (metabolite 5303307; 

expiration date: 7/1/14), and M800H35 (metabolite 5303308; expiration date: 7/1/14) are 

currently available in the National Pesticide Standards Repository [source: personal 

communication with T. Cole of ACL/BEAD, 4/2/13]. 

860.1850/860.1900 Confined/Field Accumulation in Rotational Crops

The previously submitted confined and field rotational crop data are adequate to satisfy data 

requirements for application rates up to 0.137 lb ai/A (1X). The available data indicate that 

residues of saflufenacil and its metabolites M800H11 and M800H35 were each <LOQ in/on all 

rotational crop matrices at a 120-day PBI. These data support the labeled rotational crop 

restriction of 4 months for all non-labeled crops. Unless the petitioner requests PBIs shorter than 

120 days, no additional data are required, and tolerances for inadvertent residues in/on rotational 

crops need not be established in conjunction with the currently proposed uses.

860.1550 Proposed Tolerances

BASF has petitioned for the establishment of permanent tolerances 40 CFR §180.649(a)(1) for 

saflufenacil, including its metabolites and degradates, in or on the agricultural commodities listed 

below. Compliance with the tolerance levels specified below is to be determined by measuring 

only the sum of saflufenacil, 2-chloro-5-[3,6-dihydro-3-methyl-2,6-dioxo-4-(trifluoromethyl)-

1(2H)-pyrimidinyl]-4-fluoro-N-[[methyl(1-methylethyl)amino]sulfonyl]benzamide, and its 

metabolites N-[2-chloro-5-(2,6-dioxo-4-(trifluoromethyl)-3,6-dihydro-1(2H)-pyrimidinyl)-4-

fluorobenzoyl]-N'-isopropylsulfamide and N-[4-chloro-2-fluoro-5-
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 14 of 15

({[(isopropylamino)sulfonyl]amino}carbonyl)phenyl]urea, calculated as the stoichiometric 

equivalent of saflufenacil in/on the following plant commodities:

Grain, cereal, forage, fodder and straw group 

16 (except rice straw) 0.1 ppm

Rice, straw 0.30 ppm

However, these tolerances are not required as rice straw is not a regulated commodity. Since the 

existing tolerance of 0.03 ppm for residues in/on rice grain (as a member of cereal grains Crop 

Group 15) is supported by the residue data reflecting the post-emergent use pattern, no changes 

in the existing tolerances for Crop Group 15 are needed.

BASF has also petitioned for the establishment of permanent tolerances 40 CFR §180.649(a)(2) 

for saflufenacil, including its metabolites and degradates, in or on the agricultural commodities 

listed below. Compliance with the tolerance levels specified below is to be determined by 

measuring only saflufenacil, 2-chloro-5-[3,6-dihydro-3-methyl-2,6-dioxo-4-(trifluoromethyl)-

1(2H)-pyrimidinyl]-4-fluoro-N-[[methyl(1-methylethyl)amino]sulfonyl]benzamide, in/on the 

following commodities:

Fish-freshwater finfish 0.01 ppm

Fish-shellfish, crustacean

Provided issues related to storage stability are resolved, the submitted magnitude of saflufenacil 

residue study in freshwater crayfish will support the proposed tolerance for residues in/on fishshellfish, crustacean. In addition, the crayfish magnitude of saflufenacil residue data can be 

translated to support the proposed tolerance for residues in/on fish-freshwater finfish.

A summary of the recommended tolerances for the current petition are listed in Table 7. The 

petitioner should submit a revised Section F reflecting the corrected commodity definitions. 

There are no Canadian or Codex maximum residue limits (MRLs) established for residues of 

saflufenacil and its metabolites in crayfish or fish. Harmonization is thus not an issue for this 

petition.

Table 7. Tolerance Summary for Saflufenacil.

Commodity

Proposed 

Tolerance (ppm)

HED-Recommended 

Tolerance (ppm)

Correct Commodity 

Definition/Comments

Grain, cereal, forage, fodder 

and straw group 16 (except 

rice straw)

0.1 - Not required as rice straw is not a 

regulated commodity.

Rice, straw 0.30 -

Fish-freshwater finfish 0.01 0.01

Fish-shellfish, crustacean 0.01 0.01

Attachments: International Residue Limit Status (IRLS) sheet.

cc: G. Kramer (RAB1)

RDI: RAB1 Chemists (7/10/13)

G.F. Kramer:S10957:PY-S:(703)305-5079:7509P:RAB1
Saflufenacil Summary of Analytical Chemistry and Residue Data DP# 407976

Page 15 of 15

IRLS Sheet.

Saflufenacil (118203; Date of Request: 07/01/2013)

Summary of U.S. and International Tolerances and Maximum Residue Limits 

Residue Definition:

U.S. Canada Mexico2 Codex3

40 CFR 180.649:

Plant: saflufenacil, including its 

metabolites and degradates, sum of 

saflufenacil, 2-chloro-5-[3,6-

dihydro-3-methyl-2,6-dioxo-4-

(trifluoromethyl)-1(2H)-

pyrimidinyl]-4-fluoro-N-

[[methyl(1-

methylethyl)amino]sulfonyl]benza

mide, and its metabolites N-[2-

chloro-5-(2,6-dioxo-4-

(trifluoromethyl)-3,6-dihydro1(2H)-pyrimidinyl)-4-

fluorobenzoyl]-N'-

isopropylsulfamide and N-[4-

chloro-2-fluoro-5-

({[(isopropylamino)sulfonyl]amino

}carbonyl)phenyl]urea, calculated 

as the stoichiometric equivalent of 

saflufenacil

Livestock: saflufenacil

2-chloro-5-[3,6-dihydro-3-methyl2,6-dioxo-4-(trifluoromethyl)-

1(2H)-pyrimidinyl]-4-fluoro-N-

[[methyl(1-

methylethyl)amino]sulfonyl]benzam

ide, including the metabolites N'-{2-

chloro-4-fluoro-5-[1,2,3,6-

tetrahydro-2,6-dioxo-4-

(trifluoromethyl)pyrimidin-1-

yl]benzoyl}-N-isopropyl sulfamide 

and N-[4-chloro-2-fluoro-5-

({[(isopropylamino)sulfonyl] 

amino}carbonyl)phenyl]urea

Livestock: 2-chloro-5-[3,6-dihydro3-methyl-2,6-dioxo-4-

(trifluoromethyl)-1(2H)-

pyrimidinyl]-4-fluoro-N-[[methyl(1-

methylethyl)amino]sulfonyl]benzam

ide

Saflufenacil

The residue 

is not fat 

soluble

Commodity1 Tolerance (ppm)/Maximum Residue Limit (mg/kg)

U.S. Canada Mexico2 Codex3

Fish-freshwater finfish 0.01

Fish-shellfish, crustacean 0.01

Completed: M. Negussie; 07/03/2013

1

Includes only commodities of interest for this action. Tolerance values should be the HED recommendations and 

not those proposed by the applicant.

2 Mexico adopts U.S. tolerances and/or Codex MRLs for its export purposes.

3 * = absent at the limit of quantitation; Po = postharvest treatment, such as treatment of stored grains. PoP = 

processed postharvest treated commodity, such as processing of treated stored wheat. (fat) = to be measured on the 

fat portion of the sample. MRLs indicated as proposed have not been finalized by the CCPR and the CAC.