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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

MEMORANDUM

Date: October 12, 2010

SUBJECT: Fomesafen Sodium. Petition for the Establishment of Tolerances and Registration 

of New Uses on Pepper and Potato, and Response to Data Gaps for Conditional 

Registration based on Submission of a Confined Rotational Crop Metabolism 

Study. Summary of Analytical Chemistry and Residue Data.

PC Code: 123802 DP Barcodes: D373544 and D382067

Decision No.: 426814 Registration No.: 100-993

Petition Nos: 9F7563 (potato), 9F7667 (pepper) Regulatory Action: Amended Section 3

Risk Assessment Type: NA Case No.: NA

TXR No.: NA CAS No.: 72178-02-0

MRID No.: See MRID Summary Table 40 CFR: §180.433

FROM: Alexandra LaMay, Biologist

Christine Olinger, Chemist

Risk Assessment Branch VII

Health Effects Division (7509P)

THROUGH: Michael S. Metzger, Chief

Risk Assessment Branch VII

Health Effects Division (7509P)

TO: Michael Walsh, PM Team 23

Herbicide Branch 

Registration Division (7505P)

MRID Summary Table

MRID No. Study Type Comments

47941402 860.1500 Pepper Crop Field Trials New DER; 47941402.de1.doc

860.1380 Pepper Storage Stability Study New DER; 47941402.de2.doc

47937602 860.1850 Confined Rotational Crop Study New DER; 47937602.der.doc
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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Executive Summary

Fomesafen sodium is a contact broadleaf herbicide in the diphenylether chemical class. The 

herbicide acts through inhibition of the enzyme protoporphyrinogen oxidase (PPO) in plants. 

The active ingredient was originally registered on 09/11/1987 by Zeneca Ag Products and was 

transferred to Syngenta Crop Protection, Inc. on 02/23/2001. Fomesafen is currently registered 

for use on the crops cotton, dry beans, snap beans, and soybeans. It is applied to treat various 

broadleaf weeds, annual grasses, perennial weeds and sedges. 

Syngenta has proposed, in PP#9F7563 and PP#9F7667, the establishment of permanent 

tolerances for residues of fomesafen in/on the following raw agricultural commodities:

Potato ....................................................................................................... 0.025 ppm

Pepper ...................................................................................................... 0.025 ppm

In support of the proposed tolerances and new crop uses, Syngenta has submitted a magnitude of

the residue study on pepper and a confined rotational crop metabolism study. Syngenta has 

previously submitted a magnitude of the residue study on potatoes (also described in DP barcode 

D365199 and D366116, 1/21/2010, C. Olinger). This Summary Document addresses the 

adequacy of the submitted residue chemistry data in support of the proposed new uses on peppers

as well as the adequacy of the submitted residue chemistry of the confined rotation crop 

metabolism study.

On peppers, Reflex® Herbicide is proposed for one broadcast preplant non-incorporated 

preemergence application up to 7 days prior to transplanting pepper seedlings at a maximum rate 

of 0.375 lb ae/A and a 60-day preharvest interval (PHI). On potatoes, Reflex® Herbicide is 

proposed for one broadcast preemergence application after planting but before potato emergence 

at a maximum rate of 0.25 lb ae/A and a 70-day PHI.

HED generally recommends that three metabolism studies on diverse crops when a pesticide is to 

be used on several different commodities. It was previously concluded that the three previouslysubmitted metabolism studies on tomatoes, soybeans and cotton were not sufficiently diverse to 

define the nature of the residue in all crops. Since no data on a root crop had been provided that 

can be translated to the proposed use on potatoes, a potato metabolism study, in which both the 

root and tops/foliage were analyzed, was required to support the proposed use on potatoes

(D365199 and D366116, 1/21/2010, C. Olinger). Syngenta has submitted a confined rotational 

crop metabolism study as part of the current submission, which HED has determined is adequate 

and is acceptable to use to determine the nature of the residue in potato. The residue of concern 

in plants is fomesafen.

There are no livestock feedstuffs associated with the proposed use on peppers (PP#9F7667). The 

only livestock feedstuffs associated with the proposed uses in PP#9F7563 are potato culls and 

processed waste. The nature of the residue in ruminants is adequately understood. At this time 

no tolerances have been established on any livestock commodity in association with the existing 

uses of fomesafen. There is no reasonable expectation of finite residues in livestock. Therefore, 

no livestock feeding studies are required to support the proposed/registered uses of fomesafen 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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sodium. Syngenta should note that if additional uses are proposed in the future which result in an 

increase in the dietary burdens, livestock feeding studies may be required.

Adequate residue analytical methods are available for the purpose of tolerance enforcement. 

Syngenta submitted a new high performance liquid chromatography method with tandem mass 

spectrometry detection (LC/MS/MS) method (GRM045.01A) as an enforcement method. The 

method uses extraction procedures similar to previous methods, SPE cleanup procedures, and the 

final determination step by LC/MS/MS for analysis of fomesafen residues. The validated limit of 

quantitation (LOQ) of the method is 0.02 ppm. Method GRM045.01A was adequately validated 

at fortification levels of 0.02 ppm and 0.2 ppm in snap beans, pinto beans (dry bean), corn oil, 

cotton, undelinted seed and gin byproducts, and soybean forage, hay, and aspirated grain 

fractions. Methods for the determination of fomesafen residues of concern in livestock 

commodities are not required at this time. 

The requirements for multiresidue method testing data for fomesafen are fulfilled. FDA 

multiresidue methods are not suitable for determining residues of fomesafen. 

Samples of raw and processed commodities of potatoes, which were collected from the 

magnitude of the residue studies, were analyzed for residues of fomesafen using a LC/MS/MS 

based on a liquid chromatography with ultraviolet detection (HPLC/UV) method (GAM-RM001/86). The method was adequately validated during concurrent analysis of samples. The 

lowest level of method validation (LLMV) was 0.025 ppm. Samples of raw commodities of 

pepper, which were collected from the magnitude of the residue studies, were analyzed for

residues of fomesafen using a HPLC/MS/MS method (TMR0626B). The method was adequately

validated during concurrent analysis of samples. The lowest level of method validation (LLMV) 

was 0.025 ppm.

Analytical standards for fomesafen are currently available in the EPA National Pesticide 

Standards Repository.

Adequate storage stability data are available to support the storage conditions and durations of 

samples collected from the magnitude of the residue studies on potato and pepper. 

The submitted field trial data for fomesafen on peppers and potatoes are acceptable and support 

the proposed uses. An adequate number of trials were conducted in the appropriate geographic 

regions at ~1x the maximum proposed rate using Reflex® Herbicide, and the appropriate

samples were collected from each test around the proposed PHI. All treated samples bore 

residues below the LLMV (<0.025 ppm). Based on these data, HED recommends a tolerance of 

0.025 ppm for residues of fomesafen in/on peppers and potatoes.

The results of submitted potato processing studies show that residues of fomesafen were each 

below the LLMV (<0.025 ppm) in/on the respective RACs following application of Reflex® 

Herbicide at 1x. Since the studies involved processing of RACs bearing nonquantifiable

residues, no measurable processing factors can be calculated. Although, the Agency would have 

preferred the use of exaggerated rates in the conduct of the processing studies to yield RACs with 

quantifiable residues, HED will not require additional processing data at this time.
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Syngenta has submitted a new confined rotational crop study reflecting separate application of 

CP- and NP-label fomesafen at the maximum seasonal application rate to rotatable crops, 

including wheat, soybean, potato, spinach, radish and carrot. This has been completed and 

reviewed by the Agency, and it has been determined that the nature of the residue in rotational 

crops is adequately understood. This confined rotational crop data satisfies the data gap of the 

conditional registrations of previous assessment (D365199 and D366116).

There is now data to support rotation to other crops beyond those commodities that are currently

registered and proposed as primary crops. All plant back intervals (PBIs) for rotational crops on 

the draft label are acceptable, including a 4 month PBI for wheat (and similar commodities), a 10 

month PBI for corn, peanuts, peas, rice, and seed corn and an 18 month PBI for alfalfa, 

sunflowers, sugar beets and sorghum. 

No Codex, Canadian, or Mexican MRLs have been established for residues of fomesafen in/on 

potato or pepper; therefore, there are no issues with international harmonization raised by this 

action. Canadian MRLs have been established for residues of fomesafen in/on dry beans, lima 

beans, snap beans, and soybeans at 0.05 ppm, and a Mexican MRL of 0.05 mg/kg has been 

established for residues of fomesafen in/on soybeans. 

Regulatory Recommendations 

HED has examined the residue chemistry database for fomesafen sodium. The deficiency

pertaining to directions for use the submission of a confined rotational crop study has been 

resolved; there are no residue chemistry issues that would preclude granting the petitioner’s 

request to amend the Reflex® Herbicide label for the purpose of adding the requested use on 

potatoes and peppers. HED recommends a registration for this herbicide on the crops requested 

and/or the revision of 40 CFR §180.433 for the establishment of tolerances for residues of 

fomesafen as follows:

Potato ....................................................................................................... 0.025 ppm

Pepper, bell ............................................................................................. 0.025 ppm

Pepper, non-bell ...................................................................................... 0.025 ppm

Also, the data gaps pertaining to the conditional registration on tomatoes, dry bean, snap bean, 

and cotton has been resolved based on submission of adequate confined rotational crop 

metabolism data.

The registrant’s most recent Reflex® Herbicide label reflects regional use of fomesafen on 

peppers. However, the residue chemistry data submitted in support of this action are of sufficient 

geographic representation to support full U.S. registration; therefore, HED recommends that 

these tolerances be listed in the general section of 40 CFR §180.433.

Tolerances for fomesafen residues are listed in 40 CFR §180.433. Currently, the single 

established tolerance is expressed in terms of “sodium salt of fomesafen, 5-[2-chloro-4-

(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide.” HED has determined that the 

residue of concern for tolerance expression is fomesafen. Therefore, the established tolerance 
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expression should be revised to be expressed in terms of fomesafen, by removing the phrase 

“sodium salt of” from 40 CFR §180.433(a).

Note to PM: According to HED’s Interim Guidance on Tolerance Expressions (5/27/09, S. 

Knizner), the tolerance expression for fomesafen should be revised to state:

“Tolerances are established for residues of fomesafen, including its metabolites and 

degradates, in or on the commodities in the table below. Compliance with the tolerance levels 

specified below is to be determined by measuring only fomesafen [5-[2-chloro-4-

(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide].”

The current tolerances listed in 40 CFR §180.433 for fomesafen in soybeans, dry beans, and snap 

(succulent) beans are 0.05 ppm. HED continues to recommend for the reduction of the following 

tolerances, as described in a previous memo (D. Davis, DP No. D325801, 4/25/06): dry beans 

and snap (succulent) beans should be reduced to 0.025 ppm and the tolerance on soybeans should 

be reduced to 0.02 ppm. Note that the lower tolerance values were used in the dietary risk 

assessment.

A human health risk assessment is forthcoming.

Residue Chemistry Deficiencies

Deficiencies - Tomato Petition (9F7563)

All data gaps previously identified by HED (DP# 365199 and 366116, 1/21/2010, C. Olinger) as 

a condition of registration under the petitions cited above have now been adequately fulfilled.

The data gap of confined accumulation in crops identified in HED (DP# 365199 and 366116, 

1/21/2010, C. Olinger) as a condition of registration for the use on tomatoes has now been 

adequately fulfilled. 

There is now data to support rotation to other crops beyond those commodities currently

registered and primary crops. The data supports a 4 month rotational interval to small grains; a

10 month rotational interval to corn, peanuts, peas, rice and seed corn; and an 18 month 

rotational interval to alfalfa, sunflowers, sugar beets, and sorghum.
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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Remaining Deficiencies – PP#s 1E6228 (Dry Bean), 9F5068 (Cotton), and 6E4653 (Snap Bean) 

The data gap of the requirement for confined rotational crop data previously identified by HED 

(DP# 365199 and 366116, 1/21/2010, C. Olinger) as a condition of registration under the 

petitions cited above have now been adequately fulfilled. 

There still remains the deficiency pertaining to storage stability listed below. 

860.1380 Storage Stability

· The registrant intends to submit a final storage stability report, including analyses 

at 18 and 24 months. When this study is submitted the registrant should ensure 

that the dates documented in the report should reflect the actual storage intervals, 

and not the proposed intervals, as there was some discrepancy in the interim 

report.

Background

The chemical name and structure of fomesafen sodium and fomesafen are listed below in Table

1. The physicochemical properties of fomesafen are listed in Table 2; data pertaining to the 

physicochemical properties of fomesafen sodium are not available.

Table 1. Test Compound Nomenclature.

Compound

F3C

Cl

O

NO2

O

N

S

CH3

O

O

Na

+

Common name Fomesafen Sodium

Company experimental name Not provided.

IUPAC name 5-(2-chloro-α,α,α-trifluoro-p-tolyloxy)-N-methylsulfonyl-2-nitrobenzamide, sodium salt

CAS name 5-[2-chloro-4-(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitro-benzamide, sodium 

salt

CAS registry number 108731-70-0

Compound F3

C

Cl

O

NO2

O

N

H

S

CH3

O

O

Common name Fomesafen

Company experimental name Not provided.

IUPAC name 5-(2-chloro-α,α,α-trifluoro-p-tolyloxy)-N-methylsulfonyl-2-nitrobenzamide

CAS name 5-[2-chloro-4-(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide

CAS registry number 72178-02-0

End-use product (EP) Reflex® Herbicide, 2 lb ae/gal SL; EPA Reg. No. 100-993
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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Table 2. Physicochemical Properties of Fomesafen.

Parameter Value Reference

Melting point/range 220-221 C HED Memo, 9/3/82, W. Anthony

pH 8.2 (94% TGAI) CSF (EPA Reg. No. 100-1017; 10/13/00)

Density 1.28 g/cm3

at 20 C HED Memo, 9/10/86, C. Trichilo

Water solubility at 25 °C 600 g/L at pH 7

<10 ppm at pH 1-2

50 mg/L

HED Memo, 9/3/82, W. Anthony

HED Memo, 9/10/86, C. Trichilo

Solvent solubility g/L

Acetone 300

Cyclohexanone 150

Methanol 25

Hexane 0.5

Xylene 1.9

HED Memo, 9/10/86, C. Trichilo

Vapor pressure <7.5 x 10-7 mm Hg at 50 C The Pesticide Manual 1

Dissociation constant, pKa 2.7 at 20 C

Octanol/water partition 

coefficient, Log(KOW)

Log KOW = 2.9 at pH 1

UV/visible absorption spectrum Not available

1 The Pesticide Manual, A World Compendium, The British Crop Protection Council (toxnet.nlm.nih.gov).

860.1200 Directions for Use

The end-use product relevant to the pepper petition (PP#9F7667) and potato petition 

(PP#9F7563) is Reflex® Herbicide (EPA Reg. No. 100-993), a soluble concentrate liquid (SL) 

formulation containing 22.8% sodium salt of fomesafen as the active ingredient (equivalent to 2 

lb ae/gal of fomesafen). Reflex® is a selective herbicide which may be applied preplant surface, 

preemergence, and/or postemergence for control or partial control of broadleaf weeds, grasses, 

and sedges in registered crops cotton, dry beans, snap beans, and soybeans. In support of the 

proposed use on peppers, the petitioner submitted a draft label for Reflex® Herbicide dated 

4/22/2010. A summary of the proposed use directions for potatoes and peppers is presented in 

Table 3A.

Table 3A. Summary of Proposed Use Directions of Reflex® Herbicide (EPA Reg. No. 100-993; 2 lb ae/gal) 

on Potatoes and Peppers.

Applic. Timing, Type, and 

Equip.

Applic. 

Rate 

(lb ae/A)

Max. No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. 

Rate

(lb ae/A)

PHI

(days) Use Directions and Limitations
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Table 3A. Summary of Proposed Use Directions of Reflex® Herbicide (EPA Reg. No. 100-993; 2 lb ae/gal) 

on Potatoes and Peppers.

Applic. Timing, Type, and 

Equip.

Applic. 

Rate 

(lb ae/A)

Max. No. 

Applic. 

per 

Season

Max. 

Seasonal 

Applic. 

Rate

(lb ae/A)

PHI

(days) Use Directions and Limitations

Peppers (Transplanted)

Broadcast preplant nonincorporated preemergence 

application up to 7 days prior 

to transplanting peppers

Ground/Aerial/Center pivot 

irrigation

0.25-

0.375 1 0.375 60

Refer to Syngenta’s Regional Use 

Map for Reflex® 1(summarized 

in the ‘General Use Directions’ 

below) for determination of 

maximum use rate that may be 

applied in each geographic 

region. Do not apply to any field 

in Regions 2, 3, 4, or 5 more than 

once every two years.

Potato

Broadcast preemergence 

application after planting but 

before potato emergence 

Ground/Aerial/Center pivot 

irrigation

0.25 1 0.25 70

Refer to Syngenta’s Regional Use 

Map for Reflex® 1(summarized 

in the ‘General Use Directions’ 

below) for determination of 

maximum use rate that may be 

applied in each geographic 

region. Do not apply to any field 

in Regions 2, 3, 4, or 5 more than 

once every two years. Do not 

apply to sweet potatoes or yams. 

Do not apply as a preplant 

incorporated application as crop 

injury may occur. Do not apply 

to emerged potato plants or 

severe crop injury will occur.

1

 The draft label specifies five use regions with specific seasonal maximum application rates. The rates range with the label use 

Region 1 having the highest seasonal application rate reflects application at 0.375 lb ae/A each year and label use Region 5 

with the lowest seasonal application rate reflects application of up to 0.1875 lb ae/A in alternate years. Details of the 

seasonal maximums for all label use Regions are presented below under “General Use Directions”.

General Use Directions

Syngenta’s regional use map for Reflex®: The draft label specifies that product may only be 

used in the eastern half of the U.S. Syngenta’s regional use map for Reflex® is subdivided into 

the following five regions:

Region 1: Reflex® may be applied at a maximum of 0.375 lb ae/A per year in Region 1 per year 

which includes the following states or portion of states: AL, AR, FL, GA, LA, MS, MO 

(counties of Bollinger, Butler, Cape Girardeu, Dunklin, Madison, Mississippi, New Madrid, 

Pemiscot, Perry, Ripley, Scott, Stoddard, and Wayne), NC, OK (East of U.S. Highway 75 and 

East of Indian Nation Parkway), SC, TN, and TX (includes area East of U.S. Highway 77 to State 

Road 239 including all of Calhoun County).

Region 2: Reflex® may be applied at a maximum of 0.375 lb ae/A in alternate years in Region 2 

which includes the following states or portion of states: DE, KY, MD, VA, WV, and South of 
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Interstate 70 in the following states: IL, IN, and OH and all areas South of the Interstate 80 to the 

intersection of U.S. Highway 15 and East of U.S. Highway 15 and U.S. Highway 522 in PA.

Region 3: Reflex® may be applied at a maximum of 0.313 lb ae/A in alternate years in Region 3 

which includes the following states or portion of states: CT, IA, ME, MA, MO (all counties 

except those listed in Region 1), NH, NJ, NY, PA (all areas except those listed in Region 2), RI, 

VT, and WI (South of U.S. Highway 18 between Prairie Du Chien and Madison, and South of 

Interstate 94 between Madison and Milwaukee), and North of Interstate 70 in the following 

states: IN, IL, and OH. 

Region 4: Reflex® may be applied at a maximum of 0.25 lb ae/A in alternate years in Region 4 

which includes the following states or portion of states: KS (all counties East of or intersected by

U.S. Highway 281), MI (Southern Peninsula), MN (all areas South of Interstate 94), NE (all 

counties East of or intersected by U.S. Highway 281), and WI (all areas, except those in Region 

3, South of Interstate 94 from MN state line to Eau Claire and South of U.S. Highway from Eau 

Claire to Green Bay plus Barron, Chippewa, Clark, Door, Dunn, Eau Claire, Kewaunee, 

Marathon, Menominee, Oconto, Polk, Shawano, and St. Croix counties. The following counties 

are excluded: Adams, Marquette, Portage, Waupaca, Waushara, and Wood). ND (all areas East 

of Interstate 29 from Fargo South to the SD state line). SD (all areas East of Interstate 29 from 

the ND state line to Watertown, all areas East of Highway 81 from Watertown to Madison and 

all areas East and South of State Road 34 and U.S. Highway 281 to the NE state line.

Region 5: Reflex® may be applied at a maximum of 0.1875 lb ae/A in alternate years in Region 

5 which includes the following states or portion of states: ND (all areas East of the U.S. 

Highway 281 except those areas in Region 4), SD (all areas East of the U.S. Highway 281 except 

those areas in Region 4), and MN (all areas South of the U.S. Highway 2 except those areas in 

Region 4).

Spray additives: The draft label specifies that spray additives cleared for use on growing crops 

under 40 CFR §180.1001 may be used in the spray mixture. A nonionic surfactant (NIS), crop 

oil concentrates (COC), or other adjuvants may be used for postemergence applications only. 

Since the proposed uses on potatoes and peppers are either preemergence or pretransplant, the 

use of surfactants is typically not needed when Reflex® is applied to these crops, as the label 

states adjuvants are not needed for preplant surface or preemergence applications unless Reflex® 

is being used in a burndown on emerged weeds. 

Application equipment: Ground applications are to be made in a minimum of 10 gal/A, and 

aerial applications are to be made in a minimum of 5 gal/A. Applications are not to be made 

through any type of irrigation equipment except center pivot systems. Reflex® alone or in tank 

mixture with other herbicides on the label, which are registered for center pivot application, may

be applied in irrigation water preemergence (after planting but before weeds or crop emerge) at 

label-recommended rates.

Tank mixtures with other products registered for use on potatoes and peppers: The draft label 

provides mixing procedures for tank mixes but does not specify specific tank mix partners for 

potatoes and peppers. The use directions state that, for tank mix combinations, the 

recommendations, restrictions, and limitations for all products must be followed and that the 
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most restrictive labeling is to apply. For preemergence application in potatoes, Reflex® may be 

tank mixed with other pesticide products registered for use in this way and timing in potatoes. 

For preplant non-incorporated preemergence applications prior to transplanting peppers, Reflex® 

may also be tank mixed with other pesticide products registered for use in this way and timing in 

peppers. 

Rotational crop plantback intervals: The draft label specifies that the rotational crops listed in 

Table 3B may be planted after applying Reflex® at recommended rates.

Table 3B. Rotational Crop Plantback Intervals Listed on the Reflex® Herbicide.

Crop To Be Planted Minimum Rotation Interval

(Days or Months After Last Reflex®

Application)

Cotton, dry beans, peppers, potatoes, snap bean, soybeans, and 

transplanted tomatoes

0

Small grains such as wheat, barley, and rye 4 months

Corn 1, peanuts, peas, rice, seed corn 10 months

To avoid crop injury, do not plant alfalfa, sunflowers, sugar beet, 

sorghum 2, or any crop within

18 months

Do not graze rotated small grain crops or harvest forage or straw for livestock.

1 Use a 12 month minimum rotation interval for popcorn in the states of OH, KY, IL, IN, IA, and Region 4 when 

applied at rates of 0.25 lb ae/A or more. Use 18 month minimum rotation for sweet corn in the states of CT, ME, 

MA, NH, NY, RI, VT, and Region 5.

2

 Sorghum may be planted back after 10 months in Region 1.

Conclusions. The available draft label for Reflex® Herbicide is adequate to allow evaluation of 

residue data relative to the proposed use on potatoes and peppers.

The available draft label and available data are adequate to evaluate rotation to other crops 

beyond those commodities that are currently registered and proposed as primary crops.

860.1300 Nature of the Residue - Plants

DER Reference: 47473901.der.doc (tomato)

DER Reference: 44754706.der.wpd (cotton)

DER Reference: 45313001.der.wpd (soybean)

Residue Chemistry Memo DP# 325801, 4/25/06, D. Davis

Residue Chemistry Memo DP#365199 and 366116, 1/21/2010, C. Olinger

Currently adequate tomato, soybean, and cotton metabolism studies are available for fomesafen, 

but no metabolism studies are available for a root crop. In a meeting with HED in 2008, the 

registrant proposed substituting the results of a confined rotational crop study for the root/tuber 

metabolism study, since the use is early season, is used in manner similar to the applications 

employed in a rotational study, and the use is not likely to result in detectable residues. 

However, the confined study had not been submitted when HED had reviewed the petition on 

potatoes (DP#365199 and 366116, 1/21/2010, C. Olinger). Syngenta has since submitted a 

confined rotational crop metabolism study for the rotational crops of wheat, soybean, potato, 

spinach, radish, and carrot (see section 860.1850). No new metabolites of concern relevant to 

root/tuber vegetables were identified in the study. HED has concluded this study is adequate to 
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support the tolerance in/on potatoes. The residue of concern in/on potatoes and peppers is 

fomesafen.

860.1300 Nature of the Residue - Livestock

MRID 00110508 (PP#2G2745, 1/28/83, A. Rathman, and PP#4F2997, 9/25/94, A. Smith)

MRID 00135635 (PP#4F2997, 9/25/84, A. Smith)

Residue Chemistry Memo DP# 325801, 4/25/06, D. Davis

Residue Chemistry Memo DP#365199 and 366116, 1/21/2010, C. Olinger

Syngenta submitted a goat metabolism study in conjunction with the temporary tolerance petition 

for soybeans (PP#2G2745). A single goat was dosed with [nitrophenyl14C]fomesafen at 0.1 

ppm in the diet for 7 days; the goat was sacrificed 16 hours after the final dose. The dosing level 

corresponds to ~2x and 5x the maximum theoretical dietary burdens to beef and dairy cattle, 

respectively. TRR reached a maximum in milk of 0.0008 ppm on Day 3. TRR were 0.003 ppm 

in liver, 0.004 ppm in kidney, <0.003 ppm in meat, and <0.005 ppm in fat. Approximately 70% 

of the dosed radioactivity was excreted. No residue characterization was conducted because of 

low radioactivity levels. 

A goat metabolism study was reviewed in conjunction with the soybean permanent tolerance 

petition (PP#4F2997). A single goat was dosed with [nitrophenyl14C]fomesafen at 10.3 ppm in 

the diet for 3 consecutive days; the goat was sacrificed 4 hours after the final dose. The dosing 

level corresponds to ~184x and 468x the maximum theoretical dietary burdens to beef and dairy

cattle, respectively. TRR were 0.20 ppm in liver, 0.28 ppm in kidney, 0.009 ppm in meat, 0.006 

ppm in fat, and 0.014 ppm in milk. Approximately 47% of the dosed radioactivity was excreted. 

Fomesafen was not found in any milk, tissue, or excreta sample. The identified metabolites were 

5-(2-chloro-α,α,α-trifluoro-p-tolyloxy)-N-methylsulfonylanthranilamide (compound XV) and 5-

(2-chloro-α,α,α-trifluoro-p-tolyloxy) anthranilic acid (compound V). Compound XV was found 

at 10% TRR in liver and 20.9% TRR in kidney, and compound V was found at 34.5% TRR in 

liver and 33.9% TRR in kidney. 

Conclusions. The available livestock metabolism data are adequate to satisfy data requirements. 

The significant components of the animal residues are fomesafen and its metabolites 5-(2-chloroα,α,α-trifluoro-p-tolyloxy) anthranilic acid (compound V) and 5-(2-chloro-α,α,α-trifluoro-ptolyloxy)-N-methylsulfonylanthranilamide (compound XV). 

Based on the residue levels in goat matrices following dosing at to ~184x and 468x the 

maximum theoretical dietary burdens to beef and dairy cattle, respectively, HED concludes that 

the proposed/registered uses of fomesafen on cotton, dry and snap beans, soybeans, potatoes, 

peppers and tomatoes result in a 40 CFR §180.6(a)(3) situation for livestock commodities; i.e., 

there is no reasonable expectation of finite residues in livestock commodities. There are no 

poultry and swine feedstuffs associated with the proposed uses.
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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860.1340 Residue Analytical Methods

MRIDs 47761903 and 47761904 (Enforcement method GRM045.01A; DP# 365199 and 366116, 1/21/2010, C. 

Olinger)

Plant commodities

Enforcement methods

Syngenta Crop Protection has previously submitted descriptions and validation data for the

enforcement method, Method GRM045.01A, which is entitled “Fomesafen Analytical Method 

for the Determination of Residues of Fomesafen in Crop Commodities by LC-MS/MS.” This 

high performance liquid chromatography with tandem mass spectrometry detection (LC/MS/MS) 

method is based on previously submitted gas chromatography with nitrogen phosphorus 

detection (GC/NPD) methods (refer to DP# 325801, D. Davis, 4/25/06) developed by Zeneca 

AG. This method is the updated version for previous Zeneca AG data-gathering methods 

(TMR08055B, TMR0879B, TMR0800B, and TMR0881B). 

Method GRM045.01A uses extraction procedures modified from the previous GC/NPD methods. 

In the revised method, fomesafen residues are extracted with 1% hydrochloric acid in 

acetonitrile. An aliquot is subjected to an SPE cleanup and analyzed using LC/MS/MS. A 

second ion transition may be monitored for confirmation. The validated LOQ is 0.02 ppm for 

fomesafen in each matrix. Representative spectra and linearity data were submitted 

demonstrating adequate sensitivity. Method GRM045.01A has been adequately validated at 

fortification levels of 0.02 ppm and 0.2 ppm in snap beans, pinto beans (dry bean), corn oil, 

cotton, undelinted seed and gin byproducts, and soybean forage, hay, and aspirated grain 

fractions. This method is adequate for enforcement purposes.

Data-collection methods

Samples of raw and processed commodities of potatoes, which were collected from the 

magnitude of the residue study, were analyzed for residues of fomesafen using a high 

performance liquid chromatography method with tandem mass spectrometry detection based on 

an HPLC/UV method (GAM-RM-001/86). The method was adequately validated during 

concurrent analysis of samples. The lowest level of method of validation (LLMV) was 0.025 

ppm for each matrix.

Samples of raw pepper, which were collected from the magnitude of the residue study, were 

analyzed for residues of fomesafen using an ultra performance liquid chromatography method 

with quadrupole mass spectrometry detection (TMR0626B) based on a GC/NPD method. This 

method is similar to the enforcement method; this method has a similar extraction method 

(fomesafen residues are extracted with 1% hydrochloric acid in acetonitrile), no SPE cleanup

step, a similar analysis method (done by HPLC/MS/MS), and a different confirmation ion. The 

method validation percent recovery ranged from 83-118%, which is within 70-120%. The 

method was adequately validated during concurrent analysis of samples, with percent recovery

ranging from 84-117%. The LLMV was 0.025 ppm for peppers.
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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Livestock commodities

Because there are no established or proposed tolerances for livestock commodities, an 

enforcement method for livestock commodities is not required.

860.1360 Multiresidue Methods

DER Reference List: 47761901.der.doc

Residue Chemistry Memo DP# 325801, 4/25/06, D. Davis

HED (DP# 325801) previously required the submission of multiresidue method testing data for 

fomesafen. In response, the petitioner submitted MRID 47761901. The submission has been 

reviewed by HED, and the Executive Summary of the study DER is reproduced below.

Syngenta Crop Protection has submitted multiresidue testing data for fomesafen (free acid) 

following testing and analysis according to FDA Multiresidue Test Guidelines in PAM Vol. I

(1/94). The Decision Tree for MRM Testing found in the Multiresidue Protocols was followed 

in determining the response patterns. Fomesafen (free acid) was tested through Protocols A, B, 

and C. Protocols D, E, and F were not tested as no residues were detected using Protocol C. The 

compound was not tested under Protocol G because it is not a substituted urea.

 

Fomesafen does not have an N-methylcarbamate structure and did not produce a response on the 

fluorescence detector under Protocol A. In Protocol B testing, methylated fomesafen was not 

recovered from Florisil; therefore, no additional work was performed under Protocol B.

Fomesafen (free acid) did not produce a response under Protocol C, using gas chromatography

with either the nitrogen phosphorus or the electron capture detector (GC/NPD or GC/ECD). 

Therefore, it was not tested using Protocol D, E, or F.

Conclusions: These data indicate that FDA multiresidue methods are not suitable for 

determining residues of fomesafen. The submitted data will be forwarded to U.S. FDA for 

further evaluation.

860.1380 Storage Stability

DER Reference: 47761902.der.doc (corn, soybean, cotton, and wheat matrices storage stability data)

DER Reference: 47473903.de1.doc (potato tuber concurrent storage stability data)

DER Reference: 47473903.de2.doc (potato processed commodities concurrent storage stability data)

DER Reference: 47473902.de1.doc (tomato fruit concurrent storage stability data)

DER Reference: 47473902.de2.doc (tomato processed commodities concurrent storage stability data)

DER Reference: 47941402.de2.doc (pepper fruit concurrent storage stability data)

Residue Chemistry Memo DP# 325801, 4/25/06, D. Davis

Residue Chemistry Memo DP# 365199 and 366116, 1/21/2010, C. Olinger

Sample storage duration and conditions 

The storage durations and conditions of potato samples from the submitted magnitude of the 

residue and processing studies are presented in Table 4; the storage durations and conditions of 

pepper samples from the submitted magnitude of the residue study are presented in Table 4. 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 14 of 30

Table 4 also includes the storage conditions and durations of samples from the crop field trial, 

processing, and field rotational crop studies which were submitted to support previous petitions 

(PP#s 1E6228, 9F5068, 6E4653, and 9F7563).

Table 4. Summary of Storage Conditions and Durations of Samples from Crop Field Trial, Processing, and 

Field Rotational Crop Studies. 

Matrix Storage 

Temperature (°C)

Actual Storage 

Duration

Interval of Demonstrated Storage Stability

Samples from Previous Petitions (PP#s 1E6228, 9F5068, and 6E4653)

reviewed under DP# 325801, 4/25/06, D. Davis

Cotton Field Trials (MRID 44754701)

Cotton gin 

byproducts

~-18 232-324 days

(7.6-10.7 months)

Storage stability data indicate that residues of 

fomesafen appear to be erratic in/on cotton gin

byproducts, but overall show general stability; 

corrected stored recoveries were 69% at 2.5 

months, 80% at 3.2 months, 142% at 8.8 

months, and 68% at 14.6 months.

Soybean Processing Study (MRID 45093601)

Soybean hulls -20 294 days

(9.7 months)

Storage stability data indicate that residues of 

fomesafen appear to be relatively stable in/on 

soybean hulls stored frozen at -31 to -3 oC for 

up to ~15 months.

Soybean refined oil 288 days

(9.5 months)

Storage stability data indicate that residues of 

fomesafen appear to be relatively stable in/on 

soybean oil for up to ~9 months but increased 

to a recovery of 149% by ~15 months.

Field Rotational Crop Study (MRID 00158936)1

Corn forage -20 235-272 days

(7.7-8.9 months)

Storage stability data indicate that residues of 

fomesafen appear to be relatively stable in/on 

corn K+CWHR, forage, and stover, and wheat 

forage and straw stored frozen at -31 to -3 oC 

for up to ~15 months.

Corn cob 178-223 days

(5.8-7.3 months)

Corn fodder 178-223 days

(5.8-7.3 months)

Wheat forage 361-388 days

(11.9-12.7 months)

Wheat straw 289-339 days

(9.5-11.1 months)

Field Rotational Crop Study (MRID 45268501)

Field corn, forage <-10 280-316 days

(9.2-10.4 months)

Storage stability data indicate that residues of 

fomesafen appear to be relatively stable in/on 

corn forage and stover, and wheat forage and 

straw stored frozen at -31 to -3 oC for up to 

~15 months.

Field corn, stover 239-279 days

(7.9-9.2 months)

Sorghum, forage 232-289 days

(7.6-9.5 months)

Sorghum, stover 182-273 days

(6.0-9.0 months)

Samples from Previous Petition (PP#9F7563)

reviewed under DP# 365199 and 366116, 1/21/2010, C. Olinger

Potato Field Trials and Processing Study (MRID 47473903)
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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Table 4. Summary of Storage Conditions and Durations of Samples from Crop Field Trial, Processing, and 

Field Rotational Crop Studies. 

Matrix Storage 

Temperature (°C)

Actual Storage 

Duration

Interval of Demonstrated Storage Stability

Potato tuber -40 to -6 316-399 days

(10.4-13.1 months)

Concurrent storage stability data indicate that 

residues of fomesafen appear to be relatively 

stable for up to 420 days in/on frozen potato 

tuber, 311 days in potato flakes, 308 days in 

potato chips, and 307 days in wet potato peel. 

Potato, tuber (RAC) -40 to -6 308 days

(10.1 months)

Potato, flakes 299 days

(9.8 months)

Potato, chips 298 days

(9.8 months)

Potato, wet peel 293 days

(9.6 months)

Tomato Field Trials and Processing Study (MRID 47473902)

Tomato fruit -40 to -5 211-302 days

(6.9-9.9 months)

Concurrent storage stability data indicate that 

residues of fomesafen appear to be relatively 

stable for up to 319 days in/on tomato fruit

and 236 days in tomato paste and puree.

Tomato, fruit (RAC) -40 to -5 241 days

(7.9 months)

Tomato, paste 229 days

(7.5 months)

Tomato, puree 229 days

(7.5 months)

Samples from Current Petition (PP#9F7667)

Pepper Field Trials (MRID 47941402)

Pepper fruit -29 to -15 458 days

(15.1 months)

Concurrent storage stability data indicate that 

residues of fomesafen appear to be relatively 

stable for up to 458 days in/on pepper fruit.

1

 For the field rotational crop study reported in MRID 00158936, the dates of sample analysis were not provided. 

The maximum storage interval for each sample, based on the study completion date, was calculated by the study 

reviewer.

Storage stability data

Storage stability data were concurrently generated with the potato field and processing studies. 

For each crop, control samples of the respective matrices were fortified with fomesafen at ~0.25 

ppm and placed in storage under the same frozen conditions as the treated samples. No zero-day

analyses were conducted on the fortified samples placed into storage. Rather, triplicate stored 

samples were analyzed along with a control sample and freshly fortified samples at an interval 

reflecting the maximum storage intervals from the field and processing studies. Average 

corrected recovery ranges of fomesafen were: 78-90% in potato tubers after 420 days, 79-99% in 

potato flakes after 311 days, 72-77% in potato chips after 308 days, and 71-81% in potato wet 

peel after 307 days. Although no 0-day analysis was conducted, the data indicate that fomesafen 

is stable under frozen storage conditions at the maximum intervals tested. These data indicate 

that no corrections of residues need to be applied to the study results.

Storage stability data were concurrently generated with the pepper field study. Control samples 

were fortified with fomesafen at ~0.25 ppm and places in storage under the same frozen storage 

conditions as the treated samples. Triplicate stored samples were analyzed along with a control 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 16 of 30

sample and freshly fortified sample at an interval reflecting the maximum storage intervals from 

the field study. Recovery ranges of fomesafen were 92-119% in pepper fruit after 458 days. 

These data indicate that fomesafen is stable under frozen storage conditions at the maximum 

interval tested. These data indicate that no corrections of residues need to be applied to the study

results.

860.1400 Water, Fish, and Irrigated Crops

There are no proposed uses that are relevant to this guideline topic.

860.1460 Food Handling

There are no proposed uses that are relevant to this guideline topic.

860.1480 Meat, Milk, Poultry, and Eggs

There are no livestock feedstuffs associated with the proposed use on peppers (PP#9F7667). 

The only livestock feedstuffs associated with the proposed uses in PP#9F7563 are potato culls 

and processed waste. The dietary burdens of fomesafen to beef and dairy cattle resulting from 

the proposed use on potato and the registered uses on cotton, dry and snap beans, and soybean, 

are presented in Table 5. The dietary burdens were calculated according to the Agency guidance 

on constructing maximum reasonably balanced diets (June 30, 2008) and used the proposed and 

existing tolerances for feedstuffs. The calculated dietary burdens are 0.054 ppm for beef cattle 

and 0.019 ppm for dairy cattle. There are no poultry and swine feedstuffs associated with the 

proposed uses. 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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Table 5. Livestock Dietary Burdens for Fomesafen.

Feedstuff Feedstuff 

Type1

% Dry 

Matter 2

% Diet 2 Estimated Tolerance Dietary Contribution 

(ppm) 3

Beef Cattle

Cotton hulls R 90 10 0.025 ppm 0.003

R not registered4 R -- 5 -- --

Potato processed 

waste

CC 15 30 0.025 ppm for potato 0.050

CC not registered/ 

reasonable4

CC -- 50 -- --

Soybean, meal5PC 92 5 0.02 ppm 0.001

 TOTAL BURDEN 100 0.054

Dairy Cattle

R not registered R -- 45 -- --

Potato processed 

waste

CC 15 10 0.025 ppm for potato 0.017

CC not registered4 CC -- 35 -- --

Soybean, meal5PC 92 10 0.02 ppm 0.002

 TOTAL BURDEN 100 0.019

1

 R = Roughage; CC = Carbohydrate concentrate; and PC = Protein concentrate.

2

 Table 1 Feedstuffs (June 2008). 

3

 Contribution = (tolerance /% DM x % in diet) for beef and dairy cattle.

4

 Although fomesafen is registered for other feedstuffs not listed in the dietary burden, only the feedstuffs which will 

result in the maximum dietary contribution were included. The calculation follows the guidance on constructing 

maximum reasonably balanced diets (June 30, 2008).

5 Currently, soybean tolerance is established at 0.05 ppm. HED has since recommended that the tolerance on 

soybean be reduced to 0.02 ppm (D. Davis, DP No. D325801, 4/25/06). HED continues to recommend that these 

tolerances be updated.

A ruminant feeding study was not submitted and is not needed for the purpose of this petition. 

HED concludes that the registered uses of fomesafen on cotton, dry and snap beans, and soybean

and the proposed use of fomesafen on potato result in a 40 CFR §180.6(a)(3) situation for 

livestock commodities; there is no reasonable expectation of finite residues in livestock. 

Therefore, no livestock feeding studies are required to support the proposed/registered uses of 

fomesafen sodium. Syngenta should note that if additional uses are proposed in the future which 

result in an increase in the dietary burden, livestock feeding studies may be required.
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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860.1500 Crop Field Trials

DER Reference List 47473903.de1 (Potato)

Residue Chemistry Memo DP# 365199 and 366116, 1/21/2010, C. Olinger

47941402.der (Pepper)

A summary of the reviewed crop field trial data for potato and pepper is presented in Table 6.

Table 6. Summary of Residue Data from Crop Field Trials with Fomesafen.

Commodity Total Applic. 

Rate

(lb ae/A)

PHI 

(days)

Residue Levels (ppm)

n Min. Max. HAFT1 Median

(STMdR)

Mean

(STMR)

Std. Dev.

Potato

(Proposed use = One preemergence application after planting but before crop emergence at 0.25 lb ae/A; 

70-day PHI)

Potato tubers 0.237-0.263 70-141 26 <0.025 <0.025 <0.025 0.025 0.025 ---

Pepper

(Proposed use = One preplant non-incorporated preemergence application up to 7 days prior to transplanting of 

peppers at 0.375 lb ae/A; 60 day PHI)

Pepper fruit 0.362-0.385 59-121 26 <0.025 <0.025 <0.025 0.025 0.025 ---

1

 HAFT = Highest Average Field Trial.

Potato

Syngenta Crop Protection has submitted field trial data for fomesafen on potatoes. Thirteen trials 

were conducted in the United States in Zones 1 (NY; 1 trial), 2 (MD, NC and NJ; 3 trials), 3 (FL; 

1 trial), 5 (MI and WI; 2 trials), 8 (CO; 2 trials), and 11 (ID and WA; 4 trials) during the 2006

growing season. 

At each test location, a single preemergence application of Reflex® Herbicide (EPA Reg. No. 

100-993) was made to potatoes at 0.237 to 0.263 lb ae (acid equivalents)/A. Reflex® Herbicide 

is a soluble concentrate liquid formulation containing 22.8% sodium salt of fomesafen as the 

active ingredient (equivalent to 2 lb ae/gal of fomesafen). Applications were made using ground 

equipment in spray volumes of 16-36 gal/A without an adjuvant. Samples of mature potatoes 

were collected at a PHI of 70-141 days. Additional samples were collected from one trial to 

conduct a processed food and feed study; refer to the 860.1520 DER for MRID 47473903 for the 

study details and results.

Samples of potatoes were analyzed for residues of fomesafen using a LC/MS/MS method based 

on an HPLC/UV method (GAM-RM-001/86), entitled “The Determination of PP021 in Soybeans 

– A High Performance Liquid Chromatographic Method,” which is an enforcement method for 

fomesafen. The method was adequate for data collection based on adequate concurrent recovery

data. The LLMV was 0.025 ppm for potato.

The maximum storage duration of potatoes from harvest to analysis was 399 days (13.1 months) 

for analysis of fomesafen. Sample storage conditions and durations are supported by concurrent 

storage stability data. However, zero-day data were not provided with the storage stability study. 

The petitioner is reminded that storage stability studies should always include a zero-day

sampling interval to ensure that the samples were fortified properly [see OPPTS 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 19 of 30

860.1380(d)(6)(i)].

Residues of fomesafen were less than the LLMV (<0.025 ppm) in/on potatoes harvested 70-141 

days following a single pre-emergence application of the 2 lb ae/gal SL formulation of fomesafen 

at a total rate of 0.237-0.263 lb ae/A.

Pepper

Syngenta Crop Protection has submitted field trial data for fomesafen on peppers. Thirteen crop

trials were conducted in the United States. Nine trials were conducted on bell peppers in Zones 2

(NJ, NC, and MD, 3 trials), 3 (FL; 1 trial), 5 (MI and OH; 2 trials ), 6 (TX; 1 trial) and 10 (CA, 2 

trials), and four trials were conducted on non-bell cultivars (chili peppers) in Region 3 (FL, 1 

trial), 6 (TX, 1 trial), 5 (MI, 1 trial), and 10 (NM, 1 trial) during the 2006 growing season. 

At each test location, a single broadcast application to soil surface of Reflex® Herbicide (EPA 

Reg. No. 100-993) was made prior to transplanting peppers at a rate of 0.362 to 0.385 lb ae/A. 

Reflex® Herbicide is a SL formulation containing 22.8% sodium salt of fomesafen as the active 

ingredient (equivalent to 2 lb ae/gal of fomesafen). Applications were made using ground 

equipment in spray volumes of 19-35 gal/A without an adjuvant. Pepper fruit samples were 

harvested at commercial maturity, 59 to 121 days after treatment, 56 to 115 days after 

transplanting.

Samples of raw pepper were analyzed for residues of fomesafen using an ultra performance 

liquid chromatography method with mass spectrometry detection (TMR0626B) based on a 

GC/NPD method. The method was adequately validated during concurrent analysis of samples. 

The LLMV was 0.025 ppm for pepper.

The maximum storage duration of pepper from harvest to analysis was 398 days (13.1 months)

for analysis of fomesafen. Sample storage conditions and durations are supported by concurrent 

storage stability data. 

Residues of fomesafen were less than the LLMV (<0.025 ppm) in/on peppers harvested 59-121

days following a single pre-transplant application of the 2 lb ae/gal SL formulation of fomesafen 

at a total rate of 0.362-0.385 lb ae/A.

Conclusions. The submitted field trials for potatoes are acceptable and support the proposed 

uses, as the potato metabolism data gap has been satisfied with the submitted confined rotational 

crop metabolism study. An adequate number of trials were conducted in the appropriate 

geographic regions at ~1x the maximum proposed rate using Reflex® Herbicide, and the 

appropriate samples were collected from each test around the proposed PHI. The confined 

rotational crop metabolism study does not identify any additional residues of concern, and thus 

the field trial data are adequate. Based on these data, HED recommends a tolerance of 0.025 

ppm for residues of fomesafen in/on potatoes.

The submitted field trial data for fomesafen on peppers are acceptable and support the proposed 

uses. An adequate number of trials were conducted in the appropriate geographic regions at ~1x 

the maximum proposed rate using Reflex® Herbicide, and the appropriate samples were 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 20 of 30

collected from each test around the proposed PHI. All treated samples bore residues below the 

LLMV (<0.025 ppm). Based on these data, HED recommends a tolerance of 0.025 ppm for 

residues of fomesafen in/on bell and non-bell peppers.

860.1520 Processed Food and Feed

DER Reference List 47473903.de2 (Potato)

Residue Chemistry Memo DP# 365199 and 366116, 1/21/2010, C. Olinger

The observed processing factors reported for potatoes, resulting from treatment at 1x, are

presented in Table 7.

Table 7. Summary of Observed Processing Factors for Fomesafen in Potatoes Following Treatment at 1x.

RAC Processed Commodity Processing Factor

Potato, tuber Flakes NC1

Chips NC

Wet peel NC

1

 NC = Not calculated. The processing factor could not be calculated because residues were below the LLMV (<0.025 ppm) in 

both the RAC and the processed fractions.

Potato

Syngenta Crop Protection submitted magnitude of the residue data for fomesafen on the 

processed commodities of potatoes. Samples used for processing were generated from two

potato field trial conducted in ID (Zone 11) during the 2006 growing season. The test 

formulation used in the trial was Reflex® Herbicide (EPA Reg. No. 100-993), a SL formulation 

containing 22.8% sodium salt of fomesafen as the active ingredient (equivalent to 2 lb ae/gal of 

fomesafen). Potatoes were harvested 130 days following a single preemergence application of a 

2 lb ae/gal SL formulation of fomesafen at 0.256 lb ae/A (~3x field application rate). 

Application was made using ground equipment in a spray volume of 20 gal/A without an 

adjuvant. The potatoes were processed into potato flakes, chips and wet peel.

Samples of potatoes and potato processed commodities were analyzed for residues of fomesafen 

using a high performance liquid chromatography method with tandem mass spectrometry

detection (LC/MS/MS) based on an HPLC/UV method (GAM-RM-001/86), entitled “The 

Determination of PP021 in Soybeans – A High Performance Liquid Chromatographic Method,” 

which is an enforcement method for fomesafen. The method was adequate for data collection 

based on adequate concurrent recovery data. The lowest level of method of validation (LLMV) 

was 0.025 ppm for potato tuber and processed commodities flakes, chips, and wet peel.

The maximum storage duration of the processing study samples were 308 days (10.1 months)

from harvest to analysis for potatoes (RAC) and 299 days (9.8 months), 298 days (9.8 months), 

and 293 days (9.6 months) from processing to analysis for potato flakes, chips and wet peel, 

respectively. Sample storage conditions and durations are supported by concurrent storage 

stability data. However, zero-day data were not provided with the storage stability study. The 

petitioner is reminded that storage stability studies should always include a zero-day sampling 

interval to establish the residue levels present at the time samples are placed into storage [see 

OPPTS 860.1380(d)(6)(i)].
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 21 of 30

Residues of fomesafen were less than the LLMV (<0.025 ppm) in/on the potato tuber (RAC) and 

potato processed commodities. Therefore, concentration factors could not be calculated. The 

petitioner is reminded that samples used in processing studies should contain field-treated 

quantifiable residues so that concentration factors can be determined. Field treatment of the 

processing samples should have been done at exaggerated application rates to ensure that the 

samples were fortified properly [see OPPTS 860.1520(c)(2)].

According to Tables 2 and 3 of OPPTS 860.1520, the theoretical concentration factors for potato 

processed fraction are 4.0x for processed waste (wet peel) and 4.7x for flakes/granules. 

Conclusions. The results of submitted potato processing study show that residues of fomesafen 

were each below the LLMV (<0.025 ppm) in/on the respective RACs following application of 

Reflex® Herbicide at ~1x. Following processing of RACs bearing nonquantifiable residues, no 

measurable processing factors can be calculated because the processed commodities of potatoes 

also bore residues below the LLMV (<0.025 ppm). The Agency would have preferred the use of 

exaggerated rates in the conduct of the processing studies to yield RACs with quantifiable 

residues; the registrant provided no justification for conducting the study at only a 1x rate. Since 

the proposed use is for preemergence application and all RAC samples from the current potato 

field trials show residues below the LLMV and the residue data cover all significant growing 

regions for the crop requested as delineated in OPPTS 860.1500, for the purpose of this petition 

only, HED recommends a waiver for the conduct of new potato processing studies at exaggerated 

rates.

The submitted processing study for potatoes is adequate, as the potato metabolism data gap has 

been satisfied with the submitted confined rotational crop metabolism study. The confined 

rotational crop metabolism study does not identify any additional residues of concern, and thus 

the potato processing study is adequate. 

860.1650 Submittal of Analytical Reference Standards

Analytical standards for fomesafen are currently available in the EPA National Pesticide 

Standards Repository (personal communication with Theresa Cole, 9/20/10). The standard has 

an expiration date of August 2012.

Analytical reference standards of fomesafen must be supplied and supplies replenished as 

requested by the Repository. The reference standards should be sent to the Analytical Chemistry

Lab, which is located at Fort Meade, to the attention of either Theresa Cole or Thuy Nguyen at 

the following address:

USEPA

National Pesticide Standards Repository/Analytical 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.)
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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860.1850 Confined Accumulation in Rotational Crops

Reference List: 47937602.der.doc

Syngenta has submitted a confined rotational crop study with [trifluoromethylphenyl-U14C]

fomesafen (TMP label; specific activity 55.8 μCi/mg) and [nitrophenyl-U14C] fomesafen (NP 

label; specific activity 56.2 μCi/mg). Each radiolabeled test substance was formulated as SL and 

applied as a single bare-ground spray in plots in Madera, CA at a rate of 0.375 lb ae/A (1x the

maximum proposed seasonal rate for any rotatable crop). Rotational crops (wheat, soybean, 

potato, spinach, radish and carrot) were planted 90/91, 224 and 270 days after soil treatment, 

after which the total radioactive residues (TRR) of the crops was quantified. Phytotoxicity

necessitated usage of the following rotational crops and plant back intervals (PBI): 90 day PBI

for wheat (forage, hay, straw, grain) as the small grain; 91 day PBI for soybeans (forage, hay, 

seeds) as a leafy vegetable and potatoes (foliage, roots) as a root vegetable; 224 day PBI for 

wheat (forage, hay, straw, grain), radish (foliage, root), and spinach (immature, mature); 270 PHI

for wheat (forage, hay, straw, grain), carrot (foliage, root), and spinach (immature, mature). Raw 

agricultural commodities (RACs) were harvested at appropriate intervals for analysis.

TRR accumulated at ≥0.01 ppm in all rotational crop matrices planted in the 90/91, 224 and 270 

day PBIs, except for radish roots.

The majority of radioactivity was extracted from rotational crop matrices using ACN/water. In

some cases, additional extractions were necessary to remove radiolabel from the PES. Typically

the PES was extracted further with ACN:0.5 M KOH, 6 M HCl, 72% sulfuric acid, 24% KOH, 

and 80% dioxane in 0.05 M HCl. 

Total radioactive residues (TRR) in RACs were determined by combustion and may be found in 

Table 8. TRR in extracts were determined by liquid scintillation counting (LSC). Fomesafen 

and its metabolites were quantified and determined by liquid chromatography with ultraviolet

detection (LC/UV), liquid chromatography- mass spectrometry (LC/MS) and nuclear magnetic 

resonance (NMR). Identification was confirmed by thin-layer chromatography (TLC).

Total radioactive residues (TRR, ppm) were highest in all commodities at the 90/91 day PBI and 

decreased at the longer PBIs of 224 and 270 days. The TRR in the 224 and 270 days PBI

samples were generally comparable. 

Residues in the wheat commodities were highest in the 90 days PBI samples with fomesafen the 

highest residue, ranging from 0.01 ppm in grain to 0.329 ppm in the hay. The other major 

residues found in wheat were trifluoroacetic acid (TFAA) conjugates in forage, hay and straw 

(0.019 – 0.064 ppm). At the later PBI intervals of 224 days and 270 days, fomesafen decreased 

in grain, forage, hay and straw. The TFAA conjugates also had the highest residues at the 90 day

PBI, 0.035, 0.064 and 0.047 ppm being the maximum residues in the forage, hay and straw, 

respectively. No other major residue was found in these commodities. 

Three different root crops were used, potatoes at the 91 day PBI, radish at the 224 day PBI and 

carrots at the 270 day PBI. The residues in the tubers or roots were low across all three crops 

(TRR < 0.01 ppm). The residue was made up of fomesafen, R290493 and TFAA conjugates. 

Residues in the potato, radish and carrot foliage tops were higher, with the major residue 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 23 of 30

comprised of fomesafen and TFAA conjugates. For potato, radish and carrot foliage, the highest 

fomesafen residues were 0.005, 0.011, and 0.017, respectively, and highest TFAA conjugate 

residues 0.013, 0.023, and 0.017 ppm TRR, respectively. R290493 found in potato foliage at 

25.9% TRR as well, at 0.007 ppm TRR.

Soybeans were planted at the 91 day PBI, and spinach at the 224 day and 270 day PBI. The 

highest residues were found in the 91 day PBI soybean forage and hay. The major components 

of the residue in the soybean forage and hay were a TFAA conjugate (0.035 – 0.136 ppm), a 

R052850 lipid conjugate (0.02 – 0.061 ppm), and R290493 (0.015 - 0.016 ppm). Residues of 

fomesafen were low (less than or equal to 0.003 ppm) or not detected in the soybean forage, hay

or seed. The only residue detected in soybean seed was 0.005 ppm TFAA conjugate. Lower 

residues were found in the immature and mature spinach at the 224 and 270 day PBI, with the 

major residue components being fomesafen and TFAA conjugate. The maximum TRR of 

fomesafen in spinach was 0.015 ppm and the maximum TRR of TFAA conjugate was 0.023 

ppm. R290493 was found in 224 day PBI immature spinach at >10% TRR, but at only 0.002 

ppm TRR.

The major components taken up in rotated crops are fomesafen and TFAA conjugates. R052850 

lipid conjugate reached 0.061 ppm and was unique to soybean forage and hay (although Peak 9 in 

90 day PBI TMP-label wheat straw may correspond to R052850). The uptake results in low 

residues of fomesafen or TFAA conjugates, except for fomesafen found in the wheat hay and 

straw at up to 0.329 ppm. 

The dates of application, harvest, combustion, extraction and analysis were reported. No storage 

stability determination was reported as processing, extraction and analysis did not exceed 4-6 

months from harvest. 

Based on the submitted confined rotation crop study, the petitioner described the metabolic 

pathway of fomesafen. Fomesafen is cleaved at the biphenyl ether linkage (probably

glutathione-mediated) to TMP moiety 2-chlor-4-trifluoromethylphenol (not observed) and Cys 

conjugate R290493. 2-chloro-4-trifluoromethylphenol is further rapidly converted to either 

TFAA conjugates (A and B) and/or R052850 lipid conjugate (in soybean foliage RACs). 

Formation of TFAA conjugates reflects opening/extensive oxidation of the phenyl ring. 

TABLE 8. Total Radioactive Residues (TRRs) in Rotational Crops.

Matrix Plant-back interval (days) NP Label TMP Label

ppm ppm

Wheat Forage 90 0.141 0.180

224 0.038 0.034

270 0.027 0.039

Wheat Hay 90 0.515 0.526

224 0.075 0.074

270 0.100 0.113

Wheat Straw 90 0.823 0.864

224 0.239 0.115

270 0.139 0.107

Wheat Grain 90 0.027 0.024

224 0.009 0.006

270 0.009 0.012
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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TABLE 8. Total Radioactive Residues (TRRs) in Rotational Crops.

Matrix Plant-back interval (days) NP Label TMP Label

ppm ppm

Soybean Forage 91 0.058 0.142

Soybean Hay 91 0.169 0.364

Soybean Seeds 91 0.013 0.025

Potato Foliage 91 0.027 0.061

Potato Root 91 0.008 0.008

Spinach, Immature 224 0.019 0.024

270 0.024 0.040

Spinach, Mature 224 0.015 0.025

270 0.013 0.029

Radish Foliage 224 0.014 0.031

Radish Roots 224 0.005 0.009

Carrot Foliage 270 0.068 0.087

Carrot Roots 270 0.004 0.010

Table 9. Summary of Major Residues Found in Fomesafen Confined Rotational Crop Study

Analyte Residues Found - %TRR (Label Position in Parentheses)

Fomesafen Wheat Forage (NP) 90/224/2701

– 65.2/68.4/70.4 Wheat Forage (TMP) 90/224/270 –

36.1/11.8/35.9

Wheat Hay (NP) 90/224/270 – 63.9/50.7/48.0 Wheat Hay (TMP) 90/224/270 –

51.9/14.9/21.2

Wheat Straw (NP) 90/224/270 – 30.4/38.1/43.2 Wheat Straw (TMP) 90/224/270 –

35.3/24.3/34.6

Wheat Grain (NP) 90/224/270 – 44.4/33.3/33.3 Wheat Grain (TMP) 90/224/270 –

25/16.7/16.7

Potato Foliage (NP) 91 day – 18.5 Potato Foliage (TMP) 91 day – 6.6

Potato Root (NP) 91 day – 25.0 Potato Root (TMP) 91 day – 25.0

Immature Spinach (NP) 224/270 – 57.9/62.5 Immature Spinach (TMP) 224/270 day –

4.2/32.5

Mature Spinach (NP) 224 /270 – 60.0/53.8 Mature Spinach (TMP) 224/270 day – 4.0/20.7

Radish Foliage (NP) 224 day – 78.6 Radish Foliage (TMP) 224 day – 19.4

Radish Root (TMP) 224 day – 44.4

Carrot Foliage (NP) 270 day – 30.9 Carrot Foliage (TMP) 270 day –19.5

Carrot Root (NP) 270 day – 25.0 Carrot Root (TMP) 270 day –10.0

Soybean Forage (NP) 91 day – 3.4 Soybean Forage (TMP) 91 day – 0.7

Soybean Hay (NP) 91 day – 1.8

R052850 

Conjugate

Soybean Forage (TMP) 91 day – 14.1 (0.02 ppm)

Soybean Hay (TMP) 91 day – 16.8(0.061 ppm)

Wheat Straw (TMP) 90/224/270 – 3.6/ND/ND (<0.031 ppm)

TFAA Conjugates Wheat Forage (TMP) 90/224/270 – 20/73.5/51.3

Wheat Hay (TMP) 90/224/270 – 12.6/64.9/45.1 

Wheat Straw (TMP) 90/224/270 – 9.9/28.7/17.8

Wheat Grain (TMP) 90/224/270 – ND/33.3/33.3

Soybean Forage (TMP) 91 day – 26.0

Soybean Hay (TMP) 91 day – 37.4

Potato Foliage (TMP) 91 day – 37.7

Potato Root (TMP) 91 day – 50.0 

Immature Spinach (TMP) 224/270 – 79.2/52.5 

Mature Spinach (TMP) 224/270 – 92.0/55.2 

Radish Foliage (TMP) 270 day –74.2 

Radish Root (TMP) 270 day –33.3 

Carrot Foliage (TMP) 270 day –19.5

Carrot Root (TMP) 270 day –40.0 

Soybean Seed (TMP) 91 day – 20.0 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

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Table 9. Summary of Major Residues Found in Fomesafen Confined Rotational Crop Study

Analyte Residues Found - %TRR (Label Position in Parentheses)

R290493

2-amino-3-(3 –

methanesulfonyla

mino-carbonyl-4-

nitrophenylsulfany1)-

propionic acid

Soybean Forage (NP) 91 day – 27.6 

Potato Foliage (NP) 91 day – 25.9 

Potato Root (NP) 91 day – 12.5 

Immature Spinach (NP) 224 day – 10.5

Wheat Forage (NP) 90/224/270 – 1.4/2.6/3.7

Wheat Straw (NP) 90/224/270 – ND/3.3/2.2

Soybean Hay (NP) 91 day – 8.9 

Immature Spinach (NP) 270 day – 4.2

Mature Spinach (NP) 270 day – 7.7 

Radish Foliage (NP) 224 day – 7.1 

1 These values refer to the plant-back interval. In days NP = nitrophenyl label. TMP = trifluoromethylphenyl label.

The major components in rotated crops are fomesafen, trifluoroacetic acid (TFAA) conjugates, 

R052850 conjugates, and R290493. The highest residues found of fomesafen were in wheat hay, 

forage and straw at levels up to 0.329 ppm for fomesafen; TFAA conjugates were found at levels 

up to 0.064 ppm in wheat commodities. The highest residues found of TFAA conjugates were in 

soybean hay at levels up to 0.136 ppm. The highest residues found of R052850 lipid conjugate 

and R290493 were in soybean forage and hay at levels up to 0.061 ppm for R052850 lipid 

conjugate and 0.016 ppm for R290493.

Conclusions. The submitted confined rotational crop data are adequate to satisfy data 

requirements. The study appears to have adequately delineated the nature of the residue in 

rotational crops. The metabolism of fomesafen appears to proceed in rotational crops via similar 

mechanisms and to be more extensive than that observed in primary crops. TFAA conjugate

metabolites were identified in rotational crops that were not identified in primary crops. HED 

has determined that the residue of concern for the tolerance expression in rotation crops is 

fomesafen per se. HED has also determined that the residue of concern for the risk assessment in 

rotational crops is fomesafen.

The submitted confined study indicated the potential for quantifiable fomesafen residues in 

rotated crop commodities at 90/91, 224 and 270 day plantback intervals.

860.1900 Field Accumulation in Rotational Crops

Reference List: 47761905 (No DER generated)

00158936.der.wpd

45268501.der.wpd

Residue Chemistry Memo DP# 325801, 4/25/06, D. Davis

Residue Chemistry Memo DP# 365199 and 366116, 1/21/2010, C. Olinger

HED previously summarized (DP# 325801, 4/25/2006, D. Davis) the available field 

accumulation data for fomesafen. The available data consisted of: (i) MRID 00110509 which 

was reviewed by the Environmental Fate and Effects Division (EFED) and was found to contain 

numerous deficiencies; (ii) MRID 00158936, a field rotational crop study on field corn and 

winter wheat; and (iii) MRID 45268501, a field rotational crop study on field corn and safened 

sorghum. HED previously concluded that the adequacy of these data cannot be determined until 

the nature of fomesafen residues in rotational crops has been delineated. 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 26 of 30

Syngenta has adequately responded to HED’s concerns and comments regarding the analytical 

method (PPRAM No. 66) used for the analysis of fomesafen from a previously submitted field

rotational crop study (MRID 00158936) (See DP barcode D365119 and 366116, C. Olinger, 

1/21/2010). Syngenta has provided detailed information/data concerning: (i) when the 

fortification of external recoveries were performed; (ii) data to support the reported LOQ of 0.01 

ppm; (iii) data demonstrating that recoveries of the internal standard are linear relative to 

recoveries of fomesafen; and (iv) information on the identity of matrices fortified to validate the 

method. This deficiency is resolved.

As for the deficiency of data concerning the nature of the residue in rotational crops, this data gap 

has been fulfilled with the submission of the confined rotational crop metabolism study as 

described above. This data can support rotation to other crops beyond those commodities that 

are currently registered and proposed as primary crops. All plant back intervals (PBIs) for 

rotational crops on the draft label are acceptable, including a 4 month PBI for small grains (wheat 

and similar commodities), a 10 month PBI for corn, peanuts, peas, rice, and seed corn, and an 18 

month PBI for alfalfa, sunflowers, sugar beets and sorghum. The submitted confined rotational 

crop study is adequate to determine the nature of residues in rotational crops; the residue of 

concern for rotational crops is fomesafen (D373600, A. LaMay, 10/12/10).

860.1550 Proposed Tolerances/Tolerance Reassessments for Fomesafen

Tolerances for fomesafen residues are listed in 40 CFR §180.433. The tolerance expression is in 

terms of “sodium salt of fomesafen, 5-[2-chloro-4-(trifluoromethyl)phenoxy]-N-

(methylsulfonyl)-2-nitrobenzamide.” HED has determined that the residue of concern for 

tolerance expression is fomesafen. Therefore, the established tolerance expression should be 

revised to be expressed in terms of fomesafen, by removing the phrase “sodium salt of” from 40 

CFR §180.433(a). In accordance with the HED Interim Guidance on Tolerance Expressions 

(5/27/09, S. Knizner), the tolerance expression for fomesafen should be revised to state:

“Tolerances are established for residues of fomesafen, including its metabolites 

and degradates, in or on the commodities in the table below. Compliance with the 

tolerance levels specified below is to be determined by measuring only fomesafen 

[5-[2-chloro-4-(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide].”

The available crop field trial data and revised analytical method will support the proposed 

tolerance of 0.025 ppm for pepper and potato. As all residues were below the LLMV (<0.025 

ppm) in/on RAC samples treated at 1x, the Agency’s tolerance spreadsheet was not used for 

determining the recommended tolerances. The petitioner’s draft label for Reflex® Herbicide 

reflects regional use of fomesafen on pepper and potato. However, the residue chemistry data 

submitted in support of this action are of sufficient geographic representation to support full U.S. 

registration; therefore, HED recommends that this tolerances be listed in the general section of 40 

CFR §180.433. Note that the commodity term for pepper should be modified as described in 

table below.

No tolerances are required for meat, milk, poultry, and eggs for the purpose of this petition. 

Syngenta should note that if additional uses are proposed in the future which result in an increase 

in the dietary burden, livestock feeding studies and animal tolerances may be required.
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 27 of 30

No Codex, Canadian, or Mexican MRLs have been established for residues of fomesafen in/on 

potato or pepper. Canadian MRLs have been established for residues of fomesafen in/on dry

beans, lima beans, snap beans, and soybeans at 0.05 ppm, and a Mexican MRL of 0.05 mg/kg 

has been established for residues of fomesafen in/on soybeans. The registrant has advised the 

Agency that they intend to petition the Canadian government for revised tolerances to address 

any potential harmonization issues raised by establishing the new tolerances requested in this 

action.

A summary of the tolerance reassessment for fomesafen sodium is presented in Table 10. 

Table 10. Tolerance Summary for Fomesafen Sodium

Commodity Established/Proposed

Tolerance (ppm)

Recommended 

Tolerance (ppm)

Comments; Correct Commodity 

Definition

Proposed Tolerance Under PP#9F7563

Potato 0.025 0.025

Proposed Tolerance Under PP#9F7667

Pepper 0.025 0.025 Pepper, bell

Pepper, non-bell
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 28 of 30

References

DP#: 325801

Subject: Fomesafen Sodium. Residue Chemistry Summary for the HED Human Health 

Risk Assessment, a Proposal To Amend Use on Soybeans, and Proposals to Add 

Uses on Cotton, Dry Bean, and Snap Bean. PP#1E6228, PP#9F5068, and 

PP#6E4653.

From: D. Davis

To: J. Stone/J. Miller

Dated: 4/25/06

MRIDs: 00158936, 00158937, 40346603, 44754701-44754704, 44754706, 44727901, 

45093601-45093604, 45237101, 45259801, 45268501-45268503, 45313001, &

45342601

DP#: 365199 and 366116

Subject: Fomesafen Sodium. Petition for the Establishment of Tolerances and Registration 

of New Uses on Potato and Tomato; and Response to Data Gaps for Conditional 

Registration on Cotton, Dry Bean, and Snap Bean. Summary of Analytical 

Chemistry and Residue Data. PP#1E6228, PP#9F5068, PP#6E4653, and 

PP#9F7563.

From: C. Olinger

To: D. Kenny/M. Walsh

Dated: 1/21/2010

MRIDs: 47473901, 47473902, 47473903, 47761901, 47761902, 47761903, 47761904, and 

47761905.

Attachments: 

Appendix I International Residue Limit Status Sheet

Appendix II Chemical Names and Structures of Metabolites Identified 
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 29 of 30

Appendix I

International Residue Limit Status Sheet

INTERNATIONAL RESIDUE LIMIT STATUS

Chemical Name: 5-[2-

chloro-4-

(trifluoromethyl)phenoxy]-

N-(methylsulfonyl)-2-

nitrobenzamide

Common Name:

Fomesafen

X Proposed tolerance

□ Reevaluated tolerance

□ Other

Date: 5/27/10

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: PP#9F7563 and PP#9F7667

DP#: D373544 and D382067

Other Identifier: 

Residue definition (step 8/CXL): N/A Reviewer/Branch: M. Metzger/RAB7

Residue definition: fomesafen per se

Crop (s) MRL (mg/kg) Crop(s) Tolerance (ppm)

Potato 0.025

Pepper 0.025

Limits for Canada Limits for Mexico

□ No Limits

X No Limits for the crops requested

□ No Limits

X No Limits for the crops requested

Residue definition: 5-[2-chloro-4-

(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-

nitrobenzamide

Residue definition: fomesafen

Crop(s) MRL (mg/kg) Crop(s) MRL (mg/kg)

Notes/Special Instructions:

S.Funk, 5/27/2010.
Fomesafen Sodium Summary of Analytical Chemistry and Residue Data DP#s: D373544 and D382067

Page 30 of 30

Appendix II

Chemical Names of Metabolites Identified

Identification of Compounds.

Common name/code

 Figure C.3.1 ID No.

Chemical name Chemical structure

Fomesafen 5-[2-chloro-4-(trifluoromethyl)phenoxy]-

N-(methylsulfonyl)-2-nitrobenzamide

F3C

Cl

O

NO2

O

N

H

S

CH3

O

O

R052850 3-chloro-4-hydroxybenzoic acid

HO

Cl

COOH

Cys conjugate of sulfonamide 

(R290493)

2-amino-3-(3 –methanesulfonylaminocarbonyl-4-nitro-phenylsulfany1)-

propionic acid

NO2

O

N

H

S

CH3

O

O

S

H2N

HO O

R012156 2-NO2-5-OH benzoic acid

HO COOH

NO2

R089135 2-NH2-5-OH benzoic acid

HO COOH

NH2

TFAA Trifluoroacetic Acid O

OH

F

F

F