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Executive Summary 

Carfentrazone-ethyl is a post-emergent herbicide of the phenyl triazolinone group used for 

control of broadleaf weeds. It acts as an inhibitor of protoporphyrinogen oxidase, which results 

in disruption of the cell membrane and desiccation of susceptible plant species. Carfentrazoneethyl is registered for use on numerous agricultural crops, turf (including golf courses and 

residential lawns), and aquatic areas. The most recent HED human-health risk assessment on 

carfentrazone-ethyl was conducted in July of 2006 (Memo, 7/14/06, M. Clock-Rust et al., 

D328332). 

HED has evaluated the status of the human-health assessments for carfentrazone-ethyl to 

determine whether sufficient data are available and whether any updates are needed to support 

Registration Review. HED has considered the most recent human-health risk assessments for 

carfentrazone-ethyl with respect to its toxicity, exposure, and usage databases, and the most 

updated Agency science policy and risk assessment methodologies to determine the scope of 

work necessary to support Registration Review. 

The toxicity database for carfentrazone-ethyl is adequate to support the existing registrations, 

with the exception of an immunotoxicity study, which is now required as a part of 40 CFR Part 

158. 

The registrant has adequately addressed all deficiencies identified in previous HED residue 

chemistry reviews. However, as part of the registration review HED is requesting revisions to 

some of the currently-registered labels and currently-established tolerances and identified issues 

concerning the livestock/fish/shellfish tolerance enforcement method (see Data Requirements 

Section for details). Provided these deficiencies are adequately addressed, the residue chemistry 

database will be considered adequate to support the resulting registrations. 

Conservative acute and chronic dietary risk assessments were previously conducted and resulted 

in exposure less than HED’s level of concern (LOC). Depending on the registrant response to 

the requested label changes and EFED’s registration review analysis concerning residues in 

drinking water, a revised dietary exposure analysis may be necessary. HED notes that the 

currently registered labels include application scenarios which were not addressed in the residue 

estimates incorporated into the previous dietary exposure analysis. However, based on the 

available residue data, the conservative nature of the previous analysis, and the carfentrazone 

screening-level usage analysis (SLUA) data, HED concludes that incorporation of these uses in 

the dietary analysis will not likely result in exposure greater than HED's LOC. 

New occupational exposure assessments will be necessary to support Registration Review. 

Several occupational handler scenarios have not been previously assessed (or are not covered by 

already assessed uses). A revised residential exposure assessment will need to be performed to 

include residential handler scenarios and updated residential post-application scenarios. A new 

aggregate exposure assessment will be necessary to support Registration Review in light of the 

requirements for a new residential exposure assessment. 
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Hazard Identification/Toxicology 

Carfentrazone-ethyl acts as an inhibitor of protoporphyrinogen oxidase, which results in 

disruption of the cell membrane and desiccation of susceptible plant species. In plants, this 

inhibition interferes with the chlorophyll biosynthetic pathway. In mammals, this inhibition 

interferes with the heme biosynthetic pathway and results in increased porphyrin levels. 

Carfentrazone-ethyl has low acute oral, dermal, and inhalation toxicity (Toxicity Categories III 

and IV). It is minimally irritating to the eyes, non-irritating to the skin, and is not a skin 

sensitizer. 

Following oral administration in the rat, carfentrazone-ethyl was rapidly absorbed as measured 

indirectly by the rapid excretion of radioactivity (>85%) within the first 24 hours after dosing in 

both sexes. The urine contained the majority of the administered dose (72-87%); feces contained 

a lesser amount (10-26%). Extensive metabolism was indicated by only a small amount of the 

parent (0.06-2.8%) found in the feces; no parent was found in the urine by 48 hours. There was 

no evidence suggestive of bioaccumulation; the total mean percentage of the administered dose 

found in all tissues and carcasses assayed was very low (0.09%, 0.08%), with the highest 

concentration found in the residual carcasses (0.08%) of both sexes. No difference in metabolic 

profile was observed between the sexes. 

The subchronic toxicity studies in rats, mice, and dogs demonstrated that the primary effects of 

carfentrazone-ethyl were on hematological parameters (decreased mean corpuscular hemoglobin 

and mean corpuscular volume), increased urinary porphyrin excretion, increased liver weights, 

and histopathology findings including hepatic pigment deposition, hepatocytomegaly, single-cell 

necrosis, and individual mitosis. The chronic toxicity studies in rats and dogs demonstrated 

increased urinary porphyrin, and microscopic examination showed hepatoxicity in rats and mice. 

Fluorescence microscopy on liver sections also revealed red fluorescent granules consistent with 

porphyrin deposits in rats and mice. 

There was no evidence of increased susceptibility in the prenatal developmental toxicity studies 

(rats and rabbits) or the multigeneration reproductive toxicity study in rats. Carfentrazone-ethyl 

induced a significant increase in litter incidences of wavy and thickened ribs in rats at a dose 

higher than the dose that caused maternal effects (staining of the abdominogenital area and of the 

cage pan liner). The rabbit prenatal developmental toxicity study did not yield any evidence of 

treatment-related prenatal developmental toxicity; no lowest-observed adverse-effect level 

(LOAEL) was identified. The offspring effects from the 2-generation reproduction study were 

based on decreased pup body weight in both sexes of the F2 generation at the highest dose tested 

(343 mg/kg/day) and at which maternal toxicity [i.e., decreased body-weight gains, increased 

liver weights, liver and bile duct histopathology, and reductions in the mean cell volume (F0 and 

F1 males, F1 females), mean cell hemoglobin (F0 and F1 males, F1 females), hematocrit (F1 

males), and hemoglobin (F1 males)] was also observed. 

Acute and subchronic neurotoxicity studies are available for carfentrazone-ethyl. Clinical signs 

(i.e., salivation) and mild decreases in motor activity were noted at day 0 only in an acute 

neurotoxicity study, while no signs of neurotoxicity were reported in a subchronic neurotoxicity 

study at the highest dose tested (1,178 mg/kg/day for males and 1,434 mg/kg/day for females). 
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In a 21-day dermal toxicity study, carfentrazone-ethyl failed to induce any type of dermal or 

systemic toxicity up to the limit dose of 1,000 mg/kg/day. 

The mutagenic test battery demonstrated that carfentrazone-ethyl is not mutagenic. In 

carcinogenicity studies in mice and rats, there was no indication of increased incidence of 

neoplasms and spontaneous tumor formation at the doses tested. 

The HED Hazard Identification Assessment Review Committee (HIARC) met on 11-March1998 (HED Doc. No. 012550) and 8-March-2001 (HED Doc. No. 014567) to evaluate the 

carfentrazone-ethyl toxicity database and to select toxicological endpoints for dietary, as well as 

occupational/residential risk assessments. The carfentrazone-ethyl toxicological database was 

deemed sufficient to evaluate exposures from the proposed/registered applications. The HIARC 

requested a 28-day inhalation toxicity study as a condition of registration. However, based on 

low volatility and low inhalation toxicity (Toxicity Category IV) for carfentrazone-ethyl and 

since the inhalation margins of exposure (MOEs) associated with requested applications were 

>1,000, a waiver of the 28-day inhalation toxicity study for the proposed uses was deemed 

acceptable [HED Standard Operating Procedure (SOP) 2002.01: Guidance: Waiver Criteria for 

Multiple-Exposure Inhalation Toxicity Studies, 15-Aug-2002]. However, the Agency is 

currently reevaluating the inhalation waiver criteria and based on this analysis, an inhalation 

study may be required in the future. 

The Food Quality Protection Act (FQPA) Safety Factor (SF) of 1X used in the carfentrazoneethyl 2006 risk assessment (Memo, 7/14/06, M. Clock-Rust et al., D328332) was based on 

policy developed in 2002. The FQPA policy was revised and updated in 2008 (see Hot Sheet 

#30). Under the current policy, previous uncertainty factors, which were utilized independently, 

are now components of the FQPA SF. In future risk assessments of carfentrazone-ethyl, the 

FQPA SF will need to be updated based upon changes in policy as well as submission of studies 

as a part of new data requirements in the 40 CFR Part 158 for conventional pesticide registration. 

The most recent risk assessment for carfentrazone-ethyl (Memo, 7/14/06, M. Clock-Rust et al., 

D328332) provided a hazard characterization and dose-response assessment for carfentrazoneethyl. A detailed listing of the endpoints, doses and uncertainty factors selected for that risk 

assessment may be found in Table 4 of this document. 

Immunotoxicity

An immunotoxicity study is required as a part of new data requirements in the 40 CFR Part 158 

for conventional pesticide registration. Because the immune system is highly complex, studies 

not specifically conducted to assess immunotoxic endpoints are inadequate to characterize a 

pesticide’s potential immunotoxicity. While data from hematology, lymphoid organ weights, 

and histopathology in routine chronic or subchronic toxicity studies may offer useful information 

on potential immunotoxic effects, these endpoints alone are insufficient to predict 

immunotoxicity. In the absence of required studies, EPA may use a database uncertainty factor 

of up to 10X. An immunotoxicity study on carfentrazone-ethyl should be conducted (see 

attachment). Once all data have been received and reviewed, the carfentrazone-ethyl 

Registration Review Team recommends that the points of departure and SFs used for risk 

assessment purposes be reexamined and a new risk assessment done, if necessary. 
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Endocrine Disruption

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor 

Screening Program (EDSP) to determine whether certain substances (including pesticide active 

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by 

a “naturally occurring estrogen, or other such endocrine effects as the Administrator may 

designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first 

group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. 

This list of chemicals was selected based on the potential for human exposure through pathways 

such as food and water, residential activity, and certain post-application agricultural scenarios. 

This list should not be construed as a list of known or likely endocrine disruptors. 

Carfentrazone-ethyl was not among the group of 58 pesticide active ingredients on the initial list 

to be screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide 

chemicals. Accordingly, EPA anticipates issuing future EDSP test orders/data call-ins for all 

pesticide active ingredients. 

Conclusions 

The toxicity database for carfentrazone-ethyl is adequate to support existing registrations and 

registration review; however, as specified in the new 40 CFR Part 158 data requirements, an 

immunotoxicity study is required, and depending on the outcome of the Agency’s reevaluation of 

the inhalation waiver criteria, an inhalation study may also be required In addition, the toxicity 

endpoint/dose selection along with the FQPA SF may need to be re-evaluated according to 

current policy for future actions. 

Residue Chemistry

HED reviewed and carfentrazone-ethyl is currently registered for application to crop groups 1-17 

and 19 as well as the following crops: acerola, atemoya, avocado, banana, birida, borage, cacao, 

cactus, canistel, canola, cherimoya, coconut, coffee, cotton, crambe, custard apple, date, feijoa, 

fig, flax, grape, guava, hops, horseradish, ilma, jaboticaba, juneberry, kava, kiwifruit, 

lingonberry, longan, lychee, mango, mustard, noni, olive, palm heart, papaya, passionfruit, 

pawpaw, peanut, persimmon, pistachio, pomegranate, pulasan, pummelo, rambutan, safflower, 

salal, sapodilla, black sapote, mamey sapote, soursop, Spanish lime, star apple, starfruit, stevia, 

strawberry, strawberrypear, sugar apple, sugarcane, sunflower, tea, ti, vanilla, wassaba, and wax 

jambu. Broadcast application to surface water is also registered. As a result of these 
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registrations, crop/livestock/fish/shellfish tolerances are established for the combined residues of 

carfentrazone-ethyl and carfentrazone-chloropropionic acid at 0.05-10 ppm (40 CFR 180.515). 

Use Directions: The following is a summary of the application scenarios evaluated by HED for 

the above listed crops: (1) cereal grain, soybean (feeding forage and hay to livestock is 

prohibited), and cotton - preplant, foliar, and harvest-aid application; (2) peanut and sugarcane - 

preplant, postemergent-banded (between rows), and harvest-aid application; (3) vegetables, herbs 

and spices, canola, sunflower, sweet sorghum, strawberry, ti, prickly pear cactus, strawberrypear, 

wasabi, stevia, and kava - preplant and postemergent-banded (between rows) application; (4) 

potato - preplant and harvest-aid application; (5) tree, vine, and bush crops; tobacco; and hops - 

soil-directed application and application directed to the base of the plant; and (6) grass and 

horseradish - foliar application. Carfentrazone-ethyl is also registered for soil-directed 

application to cranberry (EPA Reg. No. 279-3308 and 279-3309); HED has not reviewed a 

petition concerning application of carfentrazone-ethyl to cranberry and a cranberry tolerance is 

not currently established. It is noted that as part of an IR-4 reduced field trial proposal, HED 

concluded that the berries crop group 13 residue data may be translated to cranberry provided the 

application scenarios were similar (D280458, T. Bloem, 24-Jan-2002); note that the IR-4 

reduced field trial proposal was not a request for registration. 

Based on the master label report provided by PRD and a review of the currently registered labels 

and the application scenarios reviewed by HED, HED requests that the labels be revised as 

follows: (1) labels with instructions for application to soybean should include a restriction 

prohibiting the feeding of soybean forage and hay to livestock; (2) labels should restrict harvestaid application to only the following crops: cereal grains, soybean, cotton, peanut, sugarcane, 

and potato; (3) labels should indicate the following rotational crop restrictions: seasonal 

application rate of <0.031 lb ai/acre - rotate to a registered crop at anytime and to all other crops 

12 months after application; seasonal application rate of >0.031 lb ai/acre - rotate to only a 

registered crop; and (4) instructions for application to cranberry should be removed from all 

labels. 

Residues of Concern: The petitioner has submitted sufficient information to determine the 

nature of the residue in/on the registered primary crops, livestock, and drinking water (see Table 

5 for a summary of the residues of concern). Based on the confined rotational crop study (0.031 

lb ai/acre; field rotational crop study has not been submitted), the Metabolism Assessment 

Review Committee (MARC) determined that carfentrazone-ethyl and F8426-ClPAc are of 

concern in rotational crops; the MARC also expressed concern for residues of the benzoic acid 

compounds if the levels found are similar to or greater than the parent and F8426-ClPAc. 

Therefore, the MARC decision memorandum did not include a definitive statement relating to 

the residues of concern in rotational crops for tolerance enforcement and risk assessment. Based 

on the confined rotational crop study, the application rates evaluated by HED for the registered 

crops, and the following HED-recommended rotational crop restrictions, residues in rotational 

crops are anticipated to be insignificant: seasonal application rate of <0.031 lb ai/acre - rotate to 

a registered crop at anytime and to all other crops 12 months after application; seasonal 

application rate of >0.031 lb ai/acre - rotate to only a registered crop. 

Analytical Enforcement Methods: An adequate method is available for enforcing the currently 

established crop tolerances (D245908, J. Stokes, 20-May-1998; D260428, T. Bloem, 23-Nov1999). The proposed livestock enforcement method P-3151M has been radiovalidated and 
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undergone a successful independent laboratory validation (ILV). HED forwarded this method to 

the Analytical Chemistry Laboratory (ACL) for a petition method validation (PMV; D305152, T. 

Bloem, 12-Jul-2004). Provided the ACL determined that method P-3151M was acceptable, 

HED concluded that method P-3151M would be appropriate for enforcement of the 

livestock/fish/shellfish tolerances (D294823, T. Bloem, 15-Jul-2004). To date, HED has not 

received information from ACL concerning the adequacy of method P-3151M for tolerance 

enforcement. The procedure to determine if an analytical method is appropriate for tolerance 

enforcement has changed such that a laboratory trial by EPA is no longer required. As part of 

the registration review process, HED will evaluate method P-3151M using this procedure and 

make a determination concerning the appropriateness of this method for tolerance enforcement. 

If the method is found to be unsuitable for tolerance enforcement, then the registrant will need to 

proposed and validate a new method. 

Magnitude of the Residue - Primary Crops, Livestock, Fish, and Shellfish: Provided the labels 

are revised as indicated above, the submitted magnitude of the residue studies are adequate and 

to support the registered applications scenarios. HED notes that the HED recommended banana 

tolerance was 0.10 ppm while the currently established banana tolerance is 0.20 ppm. In 

addition, HED previously recommended that the following established tolerances be deleted: 

cotton hulls, meal, and oil (D303274, T. Bloem, 19-May-2004); barley flour, barley bran, millet 

flour, oat flour, rye flour, rye bran, wheat bran, wheat flour, wheat middlings, wheat shorts, and 

wheat germ (D351363, T. Bloem, T. Bloem, 14-May-2008); and caneberry subgroup 13A (berry 

crop group 13 tolerance has been established at the same level; D296322, T. Bloem et al., 21-Jul2004). Also, the cereal grain forage, hay, stover, and straw tolerances need to be altered as there 

are conflicting commodity definitions and/or tolerance levels. 

Conclusions 

The registrant has adequately addressed all deficiencies identified in previous HED residue 

chemistry reviews. However, HED as identified the following issues during registration review. 

●The registrant should revise the labels as follows: (1) labels with instructions for application to 

soybean should include a restriction prohibiting the feeding of soybean forage and hay to 

livestock; (2) labels should restrict harvest-aid application to only the following crops: cereal 

grains, soybean, cotton, peanut, sugarcane, and potato; (3) labels should indicate the following 

rotational crop restrictions: seasonal application rate of <0.031 lb ai/acre - rotate to a registered 

crop at anytime and to all other crops 12 months after application; seasonal application rate of 

>0.031 lb ai/acre - rotate to only a registered crop; and (4) instructions for application to 

cranberry should be removed from all labels. 

●As part of the registration review process, HED will evaluate method P-3151M to determine 

the suitability of this method for enforcement of the livestock/fish/shellfish tolerances. If the 

method is found to be unsuitable for tolerance enforcement, then the registrant will need to 

proposed and validate a new method. 

●The banana tolerance should be lowered to 0.10 ppm and the following currently-established 

tolerances should be deleted: cotton hulls, cotton meal, cotton oil, barley flour, barley bran, 

millet flour, oat flour, rye flour, rye bran, wheat bran, wheat flour, wheat middlings, wheat 

shorts, wheat germ, and caneberry subgroup 13A. Also, the cereal grain forage, hay, stover, and 

straw tolerances need to be altered as there are conflicting commodity definitions and/or 

tolerance levels. Finally, the tolerance expression should be updated as follows to conform to 

current standards: Tolerances are established for residues of carfentrazone-ethyl, including its 
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metabolites and degradates, in or on the commodities listed below. Compliance with the 

following tolerance levels is to be determined by measuring carfentrazone-ethyl (ethyl alpha-2-

dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-

fluorobenzenepropanoate) and its metabolite carfentrazone-chloropropionic acid (alpha, 2-

dichloro-5-[4-difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-

fluorobenzenepropanoic acid). 

Dietary Exposure 

Acute and chronic dietary risk assessments were previously conducted using the Dietary 

Exposure Evaluation Model - Food Consumption Intake Database (DEEM-FCIDTM, ver. 2.03; 

D328829, T. Bloem, 14-Jun-2006). DEEM-FCID incorporates food consumption data from the 

USDA’s Continuing Surveys of Food Intakes by Individuals (CSFII; 1994-1996 and 1998). The 

acute and chronic analyses assumed 100% crop treated, DEEM (ver. 7.81) default processing 

factors, and modeled (Pesticide Root Zone Model/Exposure Analysis Modeling System; 

PRZM/EXAMS) drinking water estimates resulting from the caneberry application rate (yielded 

the highest drinking water concentrations). Tolerance level residues were assumed for livestock, 

fish, shellfish, cereal grain, and cotton commodities. Since the residues of concern for risk 

assessment for the remaining commodities includes compounds which are not included in the 

tolerance expression, the acute and chronic analyses did not employ tolerance-level residues for 

these commodities. However, the residues used in the risk assessment for these commodities are 

considered conservative estimates of expected residues following treatment at the maximum 

labeled rate. The resulting acute (≤1% aPAD; children 1-2 years old were the most highly 

exposed subgroup) and chronic (≤89% cPAD; children 1-2 years old were the most highly 

exposed subgroup) exposure estimates are less than HED’s level of concern. 

Conclusions 

Depending on the registrant response to the requested label changes and EFED’s registration 

review analysis concerning residues in drinking water, a revised dietary exposure analysis may 

be necessary. HED notes that the currently registered labels include application scenarios which 

were not addressed in the residue estimates incorporated into the previous dietary exposure 

analysis. Based on the available residue data, the conservative nature of the previous analysis, 

and the carfentrazone SLUA data, HED concludes that incorporation of these uses in the dietary 

analysis will not likely result in exposure greater than HED's LOC. 

Residential Exposure

Carfentrazone-ethyl is registered for use on lawns and turf, including golf courses and residential 

lawns. It is also registered for aquatic applications. The residential scenarios that have been 

assessed previously for carfentrazone-ethyl include only postapplication scenarios for the 

residential lawn use and the aquatic use (see Table 6). The currently registered residential use 

patterns, maximum application rates and formulations are provided in Table 7. 

Residential Handlers

HED has determined that residential handlers are likely to be exposed to carfentrazone-ethyl 

residues via dermal and inhalation routes during mixing, loading, and applying activities from 

the residential lawn use. HED expects the duration of these exposures to be short-term (1-30 

days) due to the infrequent use pattern associated with the carfentrazone-ethyl products. No 
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residential handler scenarios have been assessed previously by HED. In the 2006 carfentrazoneethyl risk assessment (D328332), it was stated that the label for review only allowed for 

application by Professional Lawn Care Operators to residential lawns and to golf courses; 

therefore, exposure to homeowners was not expected. However, a review of the currently 

registered carfentrazone-ethyl product labels indicated that there are registered labels for home 

lawn use that do not restrict application to professionals only. 

 

Residential Post-Application

HED has determined that there is potential for post-application exposure to adults and children 

from the turf and aquatic uses of carfentrazone-ethyl. In the July 2006 risk assessment 

(D328332), a residential post-application exposure assessment was conducted that assessed 

incidental oral exposure to children from the home lawn use, as well as inhalation and ingestion 

exposure to adult and child swimmers from the aquatic use. No chemical-specific data were 

available; therefore, the Residential SOPs, as well as HED’s Swimmer Exposure Assessment 

Model (SWIMODEL) V 1.0 (W. Dang and Versar, 27-MAR-1999), were used to estimate 

exposure. 

All residential incidental oral exposure and risk estimates for the home lawn use were below 

HED’s LOC (MOEs ≥100) at an application rate of 0.031 lb ai/A. All incidental oral and 

inhalation exposure and risk estimates for the aquatic uses were below HED’s LOC (MOEs 

≥100) at an application rate of 0.2 lb ai/A. 

During review of the previous carfentrazone-ethyl risk assessments and review of the currently 

registered carfentrazone-ethyl labels, it was noted that the 2006 assessment used an application 

rate of 0.03 lb ai/A for the home lawn use, whereas a label review for carfentrazone-ethyl 

revealed a higher registered application rate for home lawns (0.04 lb ai/A). 

Based on the Agency's current practices, a quantitative postapplication inhalation exposure 

assessment has not been performed for carfentrazone-ethyl at this time. However, volatilization 

of pesticides may be a potential source of postapplication inhalation exposure to individuals 

nearby to pesticide applications. The Agency sought expert advice and input on issues related to 

volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) 

Scientific Advisory Panel (SAP) in December 2009. The Agency received the SAP’s final report 

on March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The 

Agency is in the process of evaluating the SAP report and may, as appropriate, develop policies 

and procedures to identify the need for and, subsequently, the way to incorporate postapplication 

inhalation exposure into the Agency's risk assessments. If new policies or procedures are put 

into place, the Agency may revisit the need for a quantitative postapplication inhalation exposure 

assessment for carfentrazone-ethyl. 

Conclusions 

There is sufficient information available to assess residential exposure. A revised residential 

assessment will need to be performed to include residential handler scenarios and updated 

residential post-application scenarios (higher turf/home lawn application rate). HED is currently 

revising its Residential SOPs, including those used to determine exposure associated with home 

lawn treatments. Reviewers should incorporate new guidance from the updated SOPs to refine 

exposure estimates. 

 
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Aggregate Risk Assessment 

Aggregate exposure risk assessments were performed for the acute, chronic, and short-term 

exposure scenarios. Since the use pattern was not expected to result in exposure of more than a 

30-day duration, longer-term aggregate assessments were not performed. A cancer aggregate 

risk assessment was not performed because carfentrazone-ethyl is not carcinogenic. 

Dietary (food and drinking water) and residential post-application residential exposures were 

considered because there is a potential for individuals to be exposed concurrently through these 

routes. All potential exposure pathways were assessed in the aggregate risk assessment. The 

acute and chronic aggregate risk assessments were conducted taking into account exposure 

estimates from dietary consumption of carfentrazone-ethyl (food and drinking water). For the 

short-term aggregate risk assessment, estimates of the residential exposure and dietary (food and 

drinking water) exposures were used. For carfentrazone-ethyl, the turf and aquatic residential 

scenario estimates were aggregated with the chronic dietary (food) to provide a worst-case 

estimate of short-term aggregate risk for the U.S. population and children 1-2 years old (the child 

population subgroup with the highest estimated chronic dietary food exposure). 

The most recent aggregate exposure assessment was conducted in July of 2006 (Memo, 7/14/06, 

M. Clock-Rust et al., D328332). Acute and chronic aggregate risks are made up only of dietary 

sources; therefore, the exposure estimates provided in the dietary exposure analysis represent 

acute and chronic aggregate exposures, respectively, and are not of concern to HED. Short-term 

aggregate exposures to carfentrazone-ethyl were not of concern to HED [i.e., MOEs were ≥ LOC 

= 100] (see Table 8). 

Conclusions 

There is sufficient information available to assess aggregate exposure. A revised aggregate 

assessment will need to be performed, which will incorporate the revised residential exposures. 

Occupational Exposure

As mentioned previously, carfentrazone-ethyl is registered for use on several agricultural crops, 

non-crop use sites, turf (including golf courses, ornamental lawns and turf, and home lawns), and 

aquatic areas. 

Occupational Handlers

No chemical-specific data were available with which to assess potential exposure to pesticide 

handlers. Therefore, occupational handler assessments were based primarily on surrogate unit 

exposures from the Pesticide Handler's Exposure Database (PHED) as presented in the PHED 

Surrogate Exposure Guide and from the Outdoor Residential Exposure Task Force (ORETF). 

The risk calculations were based on maximum application rates and assuming maximum area 

treated per day. Handler's exposure and risk were calculated at two levels of mitigation: baseline 

(long pants, a long-sleeved shirt, no chemical-resistant gloves, and no respirator) and personalprotective equipment (PPE; baseline clothing with chemical-resistant gloves and/or respirator, 

when necessary). The occupational handler scenarios that have been previously assessed are 

listed in Table 9. The currently registered occupational use patterns, maximum application rates 

and formulations are provided in Table 10. 
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The most recent occupational handler exposure assessment was conducted in July of 2006 

(Memo, 7/14/06, M. Clock-Rust et al., D328332). Provided that commercial pesticide handlers 

used label-prescribed PPE (i.e., long pants, long-sleeved shirt, shoes + socks and protective 

gloves), all assessed MOEs were not of concern to HED (i.e., MOEs were ≥LOC = 100). 

The following items were noted during review of the previous carfentrazone-ethyl risk 

assessments and review of the currently registered carfentrazone-ethyl product labels: 

• The flagger scenario for all uses that allow for aerial application was only previously 

assessed at a rate of 0.016 lb ai/A, but a review of carfentrazone-ethyl product labels 

indicates higher rates are registered for aerial applications. 

• For certain crops/use sites, there are higher application rates allowed on currently 

registered labels than have been assessed previously. 

• For scenarios that allow for spot treatments (indicating use of handheld equipment), 

mixer/loader/applicator exposures from use of handheld equipment have not been 

assessed previously (or have not been assessed using maximum allowable rates/area 

treated and/or appropriate unit exposures). 

Conclusions 

There is sufficient information available to assess occupational handler exposure. Several 

occupational handler scenarios need to be assessed, which have not been assessed previously, or 

need to be reassessed based on higher application rates or area treated. 

Occupational Post-Application

An appropriate endpoint attributable to exposure through the dermal route for carfentrazoneethyl was not identified. Therefore, dermal postapplication exposure assessments have not been 

performed for carfentrazone-ethyl. 

Based on the Agency's current practices, a quantitative occupational post-application inhalation 

exposure assessment has not been performed for carfentrazone-ethyl. However, there are 

multiple potential sources of post-application inhalation exposure to individuals performing postapplication activities in previously treated fields. These potential sources include volatilization 

of pesticides and resuspension of dusts and/or particulates that contain pesticides. The Agency 

sought expert advice and input on issues related to volatilization of pesticides from its FIFRA 

SAP in December 2009. The Agency received the SAP’s final report on March 2, 2010 

(http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The Agency is in the 

process of evaluating the SAP report as well as available postapplication inhalation exposure 

data generated by the Agricultural Reentry Task Force and may, as appropriate, develop policies 

and procedures, to identify the need for and, subsequently, the way to incorporate occupational 

post-application inhalation exposure into the Agency's risk assessments. If new policies or 

procedures are put into place, the Agency may revisit the need for a quantitative occupational 

post-application inhalation exposure assessment for carfentrazone-ethyl. 

Conclusions 

There is sufficient information available to assess occupational postapplication exposure. 

Currently, since there are no dermal points of departure for carfentrazone-ethyl, a dermal 

postapplication exposure assessment is not necessary. Based on the Agency's current practices, a 

quantitative occupational post-application inhalation exposure assessment has not been performed 

for carfentrazone-ethyl; however, if new policies or procedures are put into place, the Agency may 

revisit the need for a quantitative occupational post-application inhalation exposure assessment. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Public Health and Pesticide Epidemiology Data 

A summary report listing incidents reported to EPA for carfentrazone-ethyl will be provided for 

the docket. The reported incidents will be screened in more detail during the development of the 

Final Work Plan for carfentrazone-ethyl. 

The OPP Incident Data System (IDS) was utilized for poisoning incident data on the active 

ingredient carfentrazone-ethyl (Memo, S. Recore, D382672, 11/30/10). IDS records incidents of 

generally high severity in more detail, in software called the main IDS. This system stores 

incident data for death, major and moderate incidents, and it includes more details about the 

location, date and nature of the incident. The less-severe human incidents are reported by 

registrants as counts, which are called aggregate summaries and are recorded in separate 

software. For IDS aggregate summaries, from January 1, 2002 to May 27, 2010, there are 37 

cases reported for carfentrazone-ethyl. Because it falls within the categories reported as counts 

(which includes minor, unknown, or no effects), there is no unique report that provides details 

about the incident, and single-chemical incidents are not distinguished from multiple-chemical 

incidents. For the main IDS, from January 1, 2002 to October 7, 2010, there is one case reported 

for single-chemical carfentrazone-ethyl only in the database. For this incident, the symptoms 

were unknown or not specified. 

Conclusions 

Based on the low frequency and severity of incident cases, there does not appear to be a concern 

at this time that would warrant further investigation. The Agency will continue to monitor the 

incident information and if a concern is triggered, additional analysis will be included in the risk 

assessment. 

Tolerance Assessment and International Harmonization 

U.S. permanent tolerances and Canadian, Mexican, and Codex maximum residue limits (MRLs) are 

summarized in Table 3. The U.S. and Canadian carfentrazone-ethyl residue definitions are 

harmonized and the numerical values are also harmonized for milk (0.05 ppm) and sorghum grain 

(0.25 ppm). For the remaining commodities for which both the U.S. and Canada have tolerances/ 

MRLs, the U.S. tolerance is expressed with two significant figures (0.10 ppm or 0.80 ppm), while 

the Canadian MRL is expressed with one significant figure (0.1 or 0.8 ppm). It is noted that 

Mexico adopts U.S. tolerances and/or Codex MRLs for its export purposes. Since there are no 

carfentrazone-ethyl Codex MRLs, the U.S. tolerances and Mexican MRLs should be harmonized. 

Environmental Justice 

Potential areas of environmental justice concerns, to the extent possible, were considered in the 

human-health risk assessment, in accordance with U.S. Executive Order 12898, “Federal Actions 

to Address Environmental Justice in Minority Populations and Low-Income Populations,” 

(http://www.hss.energy.gov/nuclearsafety/env/guidance/justice/eo12898.pdf). The OPP 

typically considers the highest potential exposures from the legal use of a pesticide when 

conducting human-health risk assessments, including, but not limited to, people who obtain 

drinking water from sources near agricultural areas, the variability of diets within the U.S., and 

people who may be exposed when harvesting crops. Should these highest exposures indicate 

potential risks of concern, OPP further refines the risk assessments to ensure that the risk 

estimates are based on the best available information. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Human Studies

Past carfentrazone-ethyl risk assessments rely in part on data from studies in which adult human 

subjects were intentionally exposed to a pesticide to determine their dermal and inhalation 

exposure. Many such studies, involving exposure to many different pesticides, comprise generic 

pesticide exposure databases such as PHED and the Outdoor Residential Exposure Task Force 

(ORETF). EPA has reviewed all the studies in these multi-pesticide generic exposure databases, 

and on the basis of available evidence has found them to have been neither fundamentally 

unethical nor significantly deficient relative to standards of ethical research conduct prevailing 

when they were conducted. There is no regulatory barrier to continued reliance on these studies, 

and all applicable requirements of EPA’s Rule for the Protection of Human Subjects of research 

(40 CFR Pat 26) have been satisfied. 

Deficiencies or Data Requirements 

Toxicology

• An immunotoxicity study is now required as a part of revised CFR 158.340.

Residue Chemistry

• The registrant should revise the labels as follows: (1) labels with instructions for application 

to soybean should include a restriction prohibiting the feeding of soybean forage and hay to 

livestock; (2) labels should restrict harvest-aid application to only the following crops: cereal 

grains, soybean, cotton, peanut, sugarcane, and potato; (3) labels should indicate the 

following rotational crop restrictions: seasonal application rate of <0.031 lb ai/acre - rotate 

to a registered crop at anytime and to all other crops 12 months after application; seasonal 

application rate of >0.031 lb ai/acre - rotate to only a registered crop; and (4) instructions for 

application to cranberry should be removed from all labels. 

• As part of the registration review process, HED will evaluate method P-3151M to determine 

the suitability of this method for enforcement of the livestock/fish/shellfish tolerances. If the 

method is found to be unsuitable for tolerance enforcement, then the registrant will need to 

proposed and validate a new method. 

• The banana tolerance should be lowered to 0.10 ppm and the following currently-established 

tolerances should be deleted: cotton hulls, cotton meal, cotton oil, barley flour, barley bran, 

millet flour, oat flour, rye flour, rye bran, wheat bran, wheat flour, wheat middlings, wheat 

shorts, wheat germ, and caneberry subgroup 13A. Also, the cereal grain forage, hay, stover, 

and straw tolerances need to be altered as there are conflicting commodity definitions and/or 

tolerance levels. Finally, the tolerance expression should be updated as follows to conform 

to current standards: Tolerances are established for residues of carfentrazone-ethyl, 

including its metabolites and degradates, in or on the commodities listed below. Compliance 

with the following tolerance levels is to be determined by measuring carfentrazone-ethyl 

(ethyl alpha-2-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol1-yl]-4-fluorobenzenepropanoate) and its metabolite carfentrazone-chloropropionic acid 

(alpha, 2-dichloro-5-[4-difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-

4-fluorobenzenepropanoic acid). 

ORE

• None. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 14 of 39 

References 

Referenced Memoranda. 

Author DP Barcode Date Title 

B. Madden D232457 27-Jan-1997 New Chemical Screen for Carfentrazone (F8426) - 

128712. Toxicology and Residue Chemistry Data 

Requirements for a Permanent Tolerance for Use of 

Carfentrazone on Field Corn, Wheat and Soybeans. 

José J. Morales et al. D236431 15-Jul-1997 CARFENTRAZONE-ETHYL - 128712. Health 

Effects Division Risk Characterization Document for 

Use of Carfentrazone-ethyl (F8426 50 DF) in/on Corn 

and Wheat (PP#6G4615). 

José J. Morales et al. D233587 24-Jul-1998 CARFENTRAZONE-ETHYL - 128712: Health 

Effects Division Risk Characterization Document for 

the First Food Use of Carfentrazone-ethyl in/on 

Corn, Soybeans, and Wheat. 

Tom Bloem et al. D258880, 

D258882, and 

D241256 

25-May2000 PP#s 7F04795 - Human Health Risk Assessment for 

the Application of Carfentrazone-Ethyl to Cereal 

Grains. DP Barcodes: D258880, D258882, and 

D241256. Submission #: S533492. Case: 288204. 

Chemical #: 128712. EPA Registration Number: 279-

3194 (AimTM and SharkTM). 

Tom Bloem et al. D266146, 

D271183, 

and D270508 

5-Apr-2001 PP#s 0F06151 (cotton), 0E06183 (caneberry), and 

002217-IGE (turfgrass) - Carfentrazone-Ethyl in/on 

Cotton, Caneberry and Turfgrass. Health Effects 

Division (HED) Risk Assessment. PC Code 128712. 

DP Barcodes D266146, D271183, and D270508. 

Case 293003, 293206, and 069065. Submissions 

S579800, S589462, and S588204. 

Tom Bloem et al. D296322 and 

D305499 

21-Jul-2004 Carfentrazone-Ethyl (PC Code 128712) - Human 

Health Risk Assessment for Proposed Aquatic 

Application of Carfentrazone-Ethyl and the 

Application of Carfentrazone-Ethyl to Numerous 

Fruit and Vegetable Crops. D296322 and D305499. 

Mary Clock-Rust et al. D328332, 

D322956 

14-Jul-2006 Carfentrazone-Ethyl. Section 3 Request for Use on 

Cereal Grain, Peanut, Soybean and Sugarcane as a 

Harvest-Aid. Health Effects Division (HED) HumanHealth Risk Assessment. 

Tim Leighton D246199 3-Jun-1998 OCCUPATIONAL AND RESIDENTIAL 

EXPOSURE ASSESSMENT AND 

RECOMMENDATIONS FOR CARFENTRAZONEETHYL (ID No. 7F4795; Chemical No. 128712) DP 

Barcode D246199. 

J. Troy Swackhammer D273969 5-Apr-2001 Occupational, Residential, and Non-Occupational 

Exposure Risk Assessment/Characterization for the 

Use of Carfentrazone-Ethyl for Postermergence 

Control of Broadleaf Weeds in Cotton and Turfgrass 

and for Control of Primocanes in Caneberries. PC 

Code: 128712 DP Barcode: D273969. 

J. Troy Swackhammer D277894 28-Sep-2001 Update to Occupational, Residential, and NonOccupational Exposure Risk 

Assessment/Characterization for the Use of 

Carfentrazone-Ethyl on Turfgrass. PC Code: 128712; 

DP Barcode: D277894. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 15 of 39 

Referenced Memoranda. 

Author DP Barcode Date Title 

M. Dow D297385 31-Dec2003 CARFENTRAZONE-ETHYL - Exposure/Risk 

Assessment for Proposed Uses of Carfentrazone-ethyl 

on Numerous Tree Fruits and Nuts, Vegetables, 

Grapes, Tobacco, Potato, Berries, Grass, Hops and for 

Aquatic Weed Control. 

Mark I. Dow D329138, 

D329139 

30- May2006 CARFENTRAZONE-ETHYL - Exposure/Risk 

Assessment for Proposed Uses of Carfentrazone-ethyl 

as a Harvest Aid on Sugarcane, Peanut, Cereal 

Grains, Sorghum and Soybean. 

J. Stokes TXR No. 

0012659 

19-Jun-1998 Carfentrazone-ethyl. Decisions of the Metabolism 

Assessment Review Committee (MARC). 

T. Bloem D294823 15-Jul-2004 Carfentrazone-ethyl. Petition for Tolerances on Fish 

and Shellfish. Summary of Analytical Chemistry and 

Residue Data. 

J. Stokes D245908 20-May1998 Carfentrazone-ethyl in/on Corn, Soybeans, and 

Wheat. Petition Method Validation Results. 

T. Bloem D260428 23-Nov1999 Analytical methodology and petition method 

validation for the quantification of carfentrazoneethyl residues in/on corn, wheat, and soybeans. 

T. Bloem D305152 12-Jul-2004 Carfentrazone-ethyl in Livestock Commodities. 

Request Petition Method Validation (PMV). 

T. Bloem D303274 19-May2004 Carfentrazone-Ethyl in/on Cotton. Review of 

Information Submitted by the Petitioner (29-May2003) Addressing the Residue Chemistry Deficiencies 

Identified in D278800 (T. Bloem, 15-Nov-2001). 

T. Bloem D351363 14-May2008 Review of Amendment (dated 21-Feb-2008) 

Submitted in Response to Residue Chemistry 

Deficiencies Identified in D328830 (T. Bloem, 26-

Apr-2006) Concerning the Harvest-Aid Application 

of Carfentrazone-Ethyl to Cereal Grains and Soybean. 

T. Bloem D280458 24-Jan-2002 Carfentrazone-ethyl in/on Various Commodities. 

Interregional Research Project No. 4 (IR-4) Reduced 

Residue Chemistry Data Set Proposal. 

T. Bloem D328829 14-Jun-2006 Carfentrazone-Ethyl - Acute and Chronic Dietary 

Exposure Assessments. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 16 of 39 

Attachments 

Attachment 1: Chemical Identity Table ....................................................................................... 17

Attachment 2: Physicochemical Properties Table ..................................................................... 178

Attachment 3: Tolerance Summary Table ................................................................................... 19

Attachment 4: Endpoint Selection Table ..................................................................................... 24

Attachment 5: Residue Chemistry Tables .................................................................................... 25

Attachment 6: Residential Exposure Tables ................................................................................ 26

Attachment 7: Adult and Child Aggregate Risk Estimates ......................................................... 27

Attachment 8: Occupational Exposure Tables ............................................................................. 28

Attachment 9: DCI Table ............................................................................................................. 38
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Attachment 1: Chemical Identity Table

Table 1. Chemical Identity.

Chemical Structure 

N

Cl F

N

N

O

CHF2

CH3

Et

O

Cl

O

Common name carfentrazone-ethyl 

Company experimental name F8426 

IUPAC name ethyl (RS)-2-chloro-3-{2-chloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-

triazol-1-yl]-4-fluorophenyl}propionic acid 

CAS name ethyl α,2-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-

fluorobenzenepropanoic acid 

CAS # 128639-02-1 

Chemical Structure 

N

Cl F

N

N

O

CHF2

CH3

HO

Cl

O

Common name carfentrazone-chloropropionic acid 

Company experimental name F8426-Cl-PAc 

CAS name α,2-dichloro-5-[4-(difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl]-4-

fluorobenzenepropanoic acid 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Attachment 2: Physicochemical Properties Table

Table 2. Physicochemical Properties of the Technical Grade Test Compound.

Melting point -22.1°C 

pH not available 

Density 1.46 g/mL at 20°C 

Water solubility (20°C) 12 mg/L 

Solvent solubility (μg/L at 20°C) acetone - >2000; toluene - 900; dichloromethane - >2000; hexane - 

30; ethanol - >2000; ethyl acetate - >2000 

Vapor pressure 1.2 x 10-7 mm Hg (25°C); 5.4 x 10-8 mm Hg (20°C) 

Dissociation constant (pKa) no dissociation constant 

Octanol/water partition coefficient Log(KOW) log Kow = 3.36 

UV/visible absorption spectrum not available 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Attachment 3: Tolerance Summary Table

Table 3. Summary of US and International Tolerances and Maximum Residue Limits. 

US Canada Mexico1 Codex2

Residue Definition: 

40CFR180.515 

carfentrazone-ethyl (ethyl- α -2-dichloro-5-[-

4-(difluoromethyl)-4,5-dihydro-3-methyl-5-

oxo-1 H -1,2,4-triazol-1-yl]-4-fluorobenzene 

propanoate) and its metabolite: carfentrazonechloropropionic acid (alpha, 2-dichloro-5-[-4-

difluoromethyl)-4,5-dihydro-3-methyl-5-oxo-1 

H -1,2,4-triazol-1-yl]-4-

fluorobenzenepropanoic acid) 

ethyl α, 2-dichloro-5-[4-

(difluoromethyl)-4,5-dihydro-3-methyl5-oxo-1H-1,2,4-triazol-1-yl]-4-

fluorobenzenepropanoate, including the 

metabolite α, 2-dichloro-5-[4-

(difluoromethyl)-4,5-dihydro-3-methyl5-oxo-1H-1,2,4-triazol-1-yl]-4-

fluorobenzenepropanoic acid 

 None 

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

Commodity US Canada Mexico Codex 

Acerola 0.10 

Almond, hulls 0.20 

Atemoya 0.10 

Avocado 0.10 

Banana 0.20 

Barley, bran 0.80 

Barley, flour 0.80 

Berry group 13 

0.10 0.1 blackberries, blueberries, currant, 

elderberries, gooseberries, huckleberries, 

loganberries, raspberries 

 

Birida 0.10 

Borage 0.10 

Cacao bean, bean 0.10 

Cactus 0.10 

Caneberry subgroup 13A 0.1 0.1 blackberries, loganberries, 

raspberries 

 

Canistel 0.10 

Canola 0.10 0.1 rapeseed (canola) 

Cattle, fat 0.10 0.1 

Cattle, meat 0.10 0.1 

Cattle, meat byproducts 0.10 0.1 

Cherimoya 0.10 

Coconut 0.10 

Coffee, bean, green 0.10 

Corn, field, forage 0.20 

Corn, sweet, forage 0.20 

Corn, sweet, kernel plus cob 

with husk removed 

0.10 0.1 

Cotton, gin byproducts 10 

Cotton, undelinted seed 0.20 

Cotton, hulls 0.60 

Cotton, meal 0.35 

Cotton, refined oil 1.0 

Crambe, seed 0.10 

Custard apple 0.10 

Date, dried fruit 0.10 

Feijoa 0.10 

Fig 0.10 

Fish 0.30 

Flax, seed 0.10 0.1 flaxseed 

Fruit, citrus, group 10 0.10 

Fruit, pome, group 11 0.10 0.1 apples, crabapples, loquats, 

mayhaws, priental pears, pears, quinces 

 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 3. Summary of US and International Tolerances and Maximum Residue Limits. 

US Canada Mexico1 Codex2

Fruit, stone, group 12 

0.10 0.1 apricots, nectarines, peaches, 

plumcots, plums, prune plums, sweet 

cherries, tart cherries 

 

Goat, fat 0.10 0.1 

Goat, meat 0.10 0.1 

Goat, meat byproducts 0.10 0.1 

Grain, aspirated grain fractions 1.8 

Grain, cereal, forage, fodder 

and straw group 16, except 

corn and sorghum; forage 

1.0 

Grain, cereal, forage, fodder 

and straw, group 16, hay 

0.30 

Grain, cereal, forage, fodder 

and straw, group 16, stover 

0.30 

Grain, cereal, forage, fodder 

and straw, group 16, except 

rice; straw 

0.10 

Grain, cereal, group 15 

0.10 0.1 barley, buckwheat, field corn, oats, 

pearl millet, proso millet, popcorn grain, 

rye, teosinte, triticale, wheat, wild rice 

 

Grain, cereal, group 15 (except 

rice grain and sorghum grain) 

0.10 0.1 barley, buckwheat, field corn, oats, 

pearl millet, proso millet, popcorn grain, 

rye, sweet corn kernel plus cob with 

husks removed, teosinte, triticale, wheat, 

wild rice 

 

Grain, cereal, stover 0.80 

Grain, cereal, straw 3.0 

Grape 0.10 0.1 

Grass, forage 5.0 

Grass, hay 8.0 

Guava 0.10 

Herbs and spices group 19 2.0 0.1 mustard seeds (oilseed type) 

Hog, fat 0.10 

Hog, meat 0.10 

Hog, meat byproducts 0.10 

Hop, dried cones 0.10 

Horse, fat 0.10 0.1 

Horse, meat 0.10 0.1 

Horse, meat byproducts 0.10 0.1 

Horseradish 0.10 0.1 Horseradish roots 

Ilama 0.10 

Jaboticaba 0.10 

Juneberry 0.10 

Kava, roots 0.10 

Kiwifruit 0.10 

Lingonberry 0.10 0.1 

Longan 0.10 

Lychee 0.10 

Mango 0.10 

Milk 0.05 0.05 

Millet, flour 0.80 

Mustard, seed 0.10 0.1 

Noni 0.10 

Nut, tree, group 14 0.10 

Oat, flour 0.80 

Okra 0.10 

Olive 0.10 

Palm heart 0.10 

Palm heart, leaves 0.10 

Papaya 0.10 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 3. Summary of US and International Tolerances and Maximum Residue Limits. 

US Canada Mexico1 Codex2

Passionfruit 0.10 

Pawpaw 0.10 

Peanut 0.10 

Peanut, hay 0.10 

Persimmon 0.10 

Pistachio 0.10 

Pomegranate 0.10 

Poultry, meat byproducts 0.10 

Pulasan 0.10 

Pummelo 0.10 

Rambutan 0.10 

Rapeseed, forage 0.10 

Rapeseed, seed 0.10 

Rice, grain 1.3 

Rice, hulls 3.5 

Rice, straw 1.0 

Rye, bran 0.80 

Rye, flour 0.80 

Safflower, seed 0.10 0.1 safflower seeds 

Salal 0.10 0.1 

Sapodilla 0.10 

Sapote, black 0.10 

Sapote, mamey 0.10 

Sheep, fat 0.10 0.1 

Sheep, meat 0.10 0.1 

Sheep, meat byproducts 0.10 0.1 

Shellfish 0.30 

Sorghum, forage 0.20 

Sorghum, grain 0.25 0.25 

Sorghum, sweet 0.10 

Soursop 0.10 

Soybean, seed 0.10 

Spanish lime 0.10 

Star apple 0.10 

Starfruit 0.10 

Stevia 0.10 

Strawberry 0.10 0.1 

Strawberrypear 0.10 

Sugar apple 0.10 

Sugarcane 0.15 

Sunflower, seed 0.10 0.1 sunflower seeds 

Tea, dried 0.10 

Ti, leaves 0.10 

Ti, roots 0.10 

Vanilla 0.10 

Vegetable, Brassica, leafy, 

group 5 

0.10 0.1 bok choy Chinese cabbages, broccoli, 

broccoli raab, Brussels sprouts, 

cabbages, cauliflower, Chinese broccoli, 

21nglish mustard cabbages, collards,, 

kale, kohlrabi, mustard greens, mustard 

spinach, napa Chinese cabbages, rape 

greens 

 

Vegetable, bulb, group 3 

0.10 0.1 chinese onions, dry bulb onions, 

garlic, great-headed garlic, green onions, 

leeks, potato onions, shallots, tree onion 

tops, welsh onion tops, 

 
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Table 3. Summary of US and International Tolerances and Maximum Residue Limits. 

US Canada Mexico1 Codex2

Vegetable, cucurbit, group 9 

0.10 0.1 balsam apples, balsam pears, 

cantaloupes, chayote fruit, Chinese 

cucumbers, Chinese waxgourds, citron 

melons, cucumbers, edible gourds, 

muskmelons (other than those listed in 

this item) pumpkins, summer squash, 

watermelons, west Indian gherkins, 

winter squash 

 

Vegetable, foliage of legume, 

except soybean, subgroup 7A 

0.10 

Vegetable, fruiting, group 8 

0.10 0.1 bell peppers, eggplants. Ground 

cherry, non-bell peppers, pepinos, pepper 

hybrids, tomatillos, tomatoes 

 

Vegetable, leafy, except 

Brassica, group 4 

0.10 0.1 Amaranth, arugula, cardoon, celery, 

celtuce, Chinese celery, corn salad, 

dandelion leaves, dock, edible leaved 

chrysanthemum, endives, fresh chervil 

leaves, fresh Florence fennel leaves and 

stalks, fresh parsley leaves, garden cress, 

garden pursiane , garland 

chrysanthemum, head lettuce, leaf 

lettuce, New Zealand spinach, orach 

leaves, radicchio, rhubarb, spinach, swiss 

chard, upland cress, vine spinach, winter 

purslane 

 

Vegetable, leaves of root and 

tuber, group 2 

0.10 

Vegetable, legume, group 6 

0.10 0.1 Dry (adzuki beans, beans, blackeyed 

peas, broad beans, catjang seeds, 

chickpeas, cowpea seed, field peas, guar 

seeds, kidney beans, lablab beans, lentils, 

lima beans, moth beans, mung beans, 

navy beans, pigeon peas, pink beans, 

pinto beans, rice beans, southern peas, 

soybeans, tepary beans, urd beans); 

edible podded (dwarf peas, jackbeans, 

moth beans, peas, pigeon peas, runner 

beans, snap beans, snow peas, soybeans, 

sugar snap peas, sword beans, wax 

beans, yardlong beans); grain lupin; 

succulent shelled ( blackeyed peas, 

broad beans, cowpeas, english peas, 

garden peas, green peas, lima beans, 

peas, pigeon peas, southern peas, 

soybeans, tepary beans, urd 

 

Vegetable, root and tuber, 

group 1 

0.10 0.1 arracacha, arrowroot, black salsify 

roots, carrot roots, cassava roots, celeriac 

roots, chayote roots, chicory roots, 

Chinese artichokes, chufa, edible 

burdock roots, edible canna, garden beet 

roots, ginger roots, ginseng roots, 

Jerusalem artichokes, lerens, oriental 

radish roots, parsnip roots, potatoes, 

radish roots, rutabaga roots, salsify roots, 

skirret roots, Spanish salsify roots, sugar 

beet roots, sweet potato roots, tanier 

corms, taro corms, true yam tubers, 

turmeric roots, turnip roots, turnip-rooted 

chervil roots, turnip-rooted parsley roots, 

yam bean roots 

 

Wasaba, roots 0.10 

Wax jambu 0.10 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 3. Summary of US and International Tolerances and Maximum Residue Limits. 

US Canada Mexico1 Codex2

Wheat, bran 0.80 

Wheat, flour 0.80 

Wheat, germ 0.80 

Wheat, middlings 0.80 

Wheat, shorts 0.80 

MRLs with no US equivalent

Barley milling fractions 0.8 

Buckwheat milling fractions 0.8 

Millet milling fractions 0.8 

Oat milling fractions 0.8 

Rye milling fractions 0.8 

Triticale milling fractions 0.8 

Wheat milling fractions 0.8 

Completed: M. Negussie; 08/09/2010 

1. Mexico adopts US tolerances and/or Codex MRLs for its export purposes. 

2. * = 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. 

Section 18 emergency exemptions. Time-limited tolerances are established for combined residues 

of the herbicide carfentrazone-ethyl and its chloropropionic acid metabolite in connection with 

use of the pesticide under section 18 emergency exemptions granted by EPA. These tolerances 

have expired and were revoked on the dates specified in the following table. 

Commodity Parts per million Expiration/Revocation Date 

Hop, dried cones 0.30 6/30/05 

Tomato, paste 0.60 6/30/07 

Tomato, puree 0.60 6/30/07 

Vegetable, fruiting, group 8 0.10 6/30/07 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 24 of 39 

Attachment 4: Endpoint Selection Table

Table 4. Summary of Toxicological Doses and Endpoints for Carfentrazone-ethyl from the July 2006 Human-Health 

Risk Assessment a.

Exposure 

Scenario 

Dose Used in Risk 

Assessment, UF 

FQPA SF and LOC for Risk 

Assessment Study and Toxicological Effects 

Acute Dietary - 

all populations NOAEL = 500 mg/kg/day FQPA SF = 1x 

aPAD = 5 mg/kg/day 

Acute Neurotoxicity-Rat; Clinical observations 

(salivation) and decreased motor activity.

Chronic Dietary – 

all populations NOAEL = 3.0 mg/kg/day FQPA SF = 1x cPAD = 0.03 mg/kg/day 

Chronic Toxicity-Rat; observations of liver 

histopathology and total urinary porphyrin.

Short-term Incidental 

Oral 

(1-30 Days) 

NOAEL = 500 mg/kg/day FQPA SF = 1x 

LOC for MOEs >100 

Acute Neurotoxicity-Rat; Clinical observations 

(salivation) and decreased motor activity.

Intermediate-term 

Incidental Oral 

(1-6 months) 

NOAEL = 50 mg/kg/day FQPA SF = 1x 

LOC for MOEs >100 

Subchronic Toxicity-Dog; decreased bodyweight gain, increased porphyrin levels. 

Dermal 

(Any Time Period) 

No systemic toxicity was seen at the limit-dose (1000 mg/kg/day) in a 21-day dermal toxicity study in 

rats; therefore, these risk assessments are not required.

Short-term Inhalation 

(1-30 days) NOAEL = 500 mg/kg/day FQPA SF = 1x 

LOC for MOEs >100 

Acute Neurotoxicity-Rat; Clinical observations 

(salivation) and decreased motor activity.

Intermediate-term 

Inhalation 

(1-6 Months) 

NOAEL = 50 mg/kg/day FQPA SF = 1x 

LOC for MOEs >100 

Subchronic Toxicity-Dog; decreased bodyweight gain, increased porphyrin levels.

Long-term Inhalation 

(more than 6 months) NOAEL = 3 mg/kg/day FQPA SF = 1x 

LOC for MOEs >100 

Chronic Toxicity-Rat; observations of liver 

histopathology and total urinary porphyrin. 

Cancer Classification: Not likely to be carcinogen; cancer risk assessment is not required. 

a. Memo, 7/14/06, M. Clock-Rust et al., D328332 

UF = uncertainty factor, FQPA SF = Special FQPA safety factor, NOAEL = no-observed adverse-effect level, LOAEL = lowestobserved adverse-effect level, PAD = population-adjusted dose (a = acute, c = chronic) RfD = reference dose, MOE = margin of 

exposure, LOC = level of concern, NA = Not Applicable. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Attachment 5: Residue Chemistry Tables

Table 5. Residues of Concern in Crops, Livestock, and Fish/Shellfish.

Matrix Tolerance Expression Residues for Risk Assessment 

cereal grain and cotton1,3 carfentrazone-ethyl and F8426-ClPAc carfentrazone-ethyl and F8426-ClPAc 

remaining registered crops2,3 carfentrazone-ethyl and F8426-ClPAc 

carfentrazone-ethyl, F8426-ClPAc, 3-OH-F8426-

ClPAc, 3-OH-F8426-BAc, F8426-BAc, and Me-3-

OH-F8426-BAc 

livestock/fish/shellfish4 carfentrazone-ethyl and F8426-ClPAc carfentrazone-ethyl and F8426-ClPAc 

rotational crops See text above. 

drinking water5 -- carfentrazone-ethyl, F8426-ClPAc, and F8426-CAc 1

 The residues of concern for risk assessment are based on the registered foliar application scenario for these crops and the 

corn, wheat, and soybean metabolism studies; see the MARC decision memorandum (J. Stokes, 19-Jun-1998) and D328332 

(M. Clock-Rust et al., 14-Jul-2006) for further information. 2

 The residues of concern for risk assessment are based on the soil-directed applications; the corn, wheat, soybean, and radish 

metabolism studies; and the confined rotational crop study; see the MARC decision memorandum (J. Stokes, 19-Jun-1998) 

and D328332 (M. Clock-Rust et al., 14-Jul-2006) for further information. 3

 HED notes that if a future foliar registration is requested for a crops other than a cereal grain or a legume vegetable, then the 

residues of concern for risk assessment will be carfentrazone-ethyl, F8426-ClPAc, 3-OH-F8426-ClPAc, 3-OH-F8426-BAc, 

and F8426-BAc (residues for tolerance enforcement will be carfentrazone-ethyl and F8426-ClPAc); this decision is based on 

the soybean, wheat, corn, and radish metabolism studies. 4

 See MARC decision memorandum (J. Stokes, 19-Jun-1998) and D294823 (T. Bloem, 15-Jul-2004) for further information. 5

 See MARC decision memorandum (J. Stokes, 19-Jun-1998) for further information. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Attachment 6: Residential Exposure Tables

Table 6. Residential Scenarios That Have Been Assessed. 

Scenario Application rate (lb ai/A) Area treated (acres) 

Mixer/Loader/Applicator: None previously assessed 

Postapplication

Hand-to-mouth incidental oral for toddlers 0.03 N/A 

Inhalation/Incidental Ingestion for swimmers 0.2 NA 

Table 7. Summary of Registered Residential Use Patterns, Formulations, and Maximum Application Rates for 

Carfentrazone-ethyl. 

Crop / Site Formulation1 Equipment Max App Rate Scenario Covered? 

M/L/A Postapp 

Residential Handler and post-application 

Residential lawns 

DF Handheld equipment 0.03 lb ai/A N Y 

Liquid Handheld equipment 0.04 lb ai/A N N 

RTU Trigger-pump 0.015 lb ai/A N Y 

Residential post-application only (PCO applied) 

Golf course turf 

EC/liquid Ground; Handheld 

equipment 0.09 lb ai/A 

N/A N/A2

DF (water 

soluble bags) 

Ground; Handheld 

equipment 0.12 lb ai/A 

1. EC = emulsifiable concentrate; DF = dry flowable; RTU = ready-to-use. 

2. Typically only dermal postapplication exposure would be assessed and there is no dermal point of departure for 

 carfentrazone-ethyl. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 27 of 39 

Attachment 7: Adult and Child Aggregate Risk Estimates 

Acute and chronic aggregate exposure assessments include food and water exposure (acute and 

chronic residential exposure is not anticipated). The acute and chronic dietary exposure analysis 

incorporated drinking water directly, and therefore, the acute and chronic dietary risk estimates 

represent acute and chronic aggregate risk for carfentrazone-ethyl. The acute and chronic 

exposure estimates are below HED’s LOC. Intermediate-term (1-6 months), non-dietary postapplication exposure to carfentrazone-ethyl is considered unlikely based on the use pattern. 

Therefore, an intermediate-term aggregate risk assessment was not performed. 

Short-term aggregate exposures were conducted by combining chronic dietary, inhalation, and 

incidental oral exposures. Short-term aggregate exposure to carfentrazone-ethyl, as a result of all 

registered and proposed uses, is less than HED’s LOC. 

Table 8. Short-Term Aggregate Risk for Carfentrazone-ethyl.

Population Subgroup NOAEL 

(mg/kg/day) 

Target 

MOE 

Average 

Food 

Exposure 

(mg/kg/day) 

Dietary 

MOE1

Residential 

Exposure2

(mg/kg/day) 

Combined 

Exposure 

(food + 

residential) 

Aggregate 

MOE3

(food + 

residential) 

General U.S. Population 500 100 0.009177 54,000 0.0001051 0.0093 54,000 

All Infants < 1 year old 500 100 0.015951 31,000 0.0009545 0.017 30,000 

Children 1-2 years old 500 100 0.026621 19,000 0.0009545 0.028 18,000 

Children 3-5 years old 500 100 0.021464 23,000 0.0002539 0.022 23,000 

Children 6-12 years old 500 100 0.013265 38,000 0.0002539 0.014 37,000 

Youth 13-19 years old 500 100 0.008021 62,000 0.0002539 0.0083 60,000 

Adults 20-49 years old 500 100 0.007154 70,000 0.0001051 0.0073 69,000 

Adults 50+ years old 500 100 0.006730 74,000 0.0001051 0.0068 73,000 

Females 13-49 years old 500 100 0.006948 72,000 0.0001051 0.0071 71,000 

1. Dietary MOE = NOAEL/exposure. 

2. Residential Exposure = total residential exposure. 

3. Aggregate MOE = (NOAEL ÷ (Avg Food Exposure + Residential Exposure)). 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Attachment 8: Occupational Exposure Tables

Table 9. Occupational Scenarios That Have Been Assessed. 

Scenario Application rate (lb ai/A) Area treated (acres) 

Mixer/Loader

(1) Liquids for aerial application 0.03 1200 

0.075 350 

(2) Wettable powders for aerial application 0.03 1200 

0.075 350 

(3) Dry flowable for aerial application 0.016 1200 

Applicator

(4) Aerial sprays 0.03 1200 

0.016 1200 

(5) Groundboom sprays 

0.03 200 

0.016 200 

0.1 80 

Flagger

(6) Aerial applications 0.016 350 

Mixer/Loader/Applicator

(7) High pressure handwand (aquatic sites) 0.2 50 

(8) Backpack (aquatic sites) 0.2 2 

(9) Handgun (lawns) 0.03 5 

 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 29 of 39 

Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

Artichoke (Jerusalem) EC/Liquid Aerial; Groundboom 0.0625 Y Y N N/A Flagger p

rate. 

Artichoke (Globe) EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

rate. 

Avocado EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Berry (caneberry, 

blackberry, boysenberry, 

black raspberry, red 

raspberry, cranberry) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.1 

N

N

N N Higher ra

previously

DF Aerial; Groundboom 0.1 

N

N

N N/A for liq

Borage seed EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

rate. 

DF Aerial; Groundboom 0.031 Y

Y

N

Bushberry (blueberry, 

currant, elderberry, 

gooseberry, huckleberry) 

EC/Liquid Aerial; Groundboom 0.096 

N

N

N

N/A 

Higher r

than has 

previou

H

DF Aerial; Groundboom 0.064 Y

Y

N

Canola 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

DF Aerial; Groundboom 0.064 Y

Y

N rate. 

Barley (small grains) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.0625 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Buckwheat 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.064 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.064 Y

Y

N N/A 

Corn (field corn, seed 

corn, popcorn, corn 

silage, sweet corn) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.064 

N

N

N N High acre

allowed o

DF Aerial; Groundboom 0.064 

N

N

N N/A labels for 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

Millet (proso and pearl; 

small grains) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.0625 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Oats (small grains) EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Rice 

EC/Liquid Aerial; Groundboom 0.064 

N

N

N

N/A 

High acre

allowed o

at 0.016 l

DF Aerial; Groundboom 0.2 

N

N

N

Rye (small grains) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.0625 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Sorghum (grain or 

forage) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.064 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.016 Y

Y

N N/A 

Teosinte (small grains) 

EC/Liquid Aerial; Groundboom 0.4 

N

N

N

N/A 

Higher r

than has 

previou

H

DF Aerial; Groundboom 0.031 Y

Y

N

Triticale (small grains) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.0625 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Wheat (small grains) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.0625 

N

N

N N High acre

allowe

Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Cotton EC/Liquid Aerial; Groundboom; Handheld equipment 0.064 

N

N

N N High acre

allowed o
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

DF Aerial; Groundboom 0.064 

N

N

N N/A 

at 0.016 l

labels. S

liqu

Crambe seed 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

DF Aerial; Groundboom 0.064 Y

Y

N rate. 

Fallow systems EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.064 Y

Y

N rate. 

Flax seed EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.064 Y

Y

N rate. 

Grape (raisin, table, 

wine) 

EC/Liquid Aerial; Groundboom 0.034 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Grasses EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Herbs and spices EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.064 Y

Y

N rate. 

Hops EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Horseradish EC/Liquid Aerial; Groundboom 0.034 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Mustard seed 

EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Okra EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.064 Y

Y

N rate. 

Pastures EC/Liquid Aerial; Groundboom 0.04 Y

Y

N N/A Flagger p

rate. 

Peanuts EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Rapeseed EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Safflower seed EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

Soybeans 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.064 

N

N

N N High acre

allowe

Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.023 Y

Y

N N/A 

Strawberry EC/Liquid Aerial; Groundboom 0.064 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.064 Y

Y

N rate. 

Sugarcane 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.031 Y

Y

N

Sunflower seed 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Tobacco 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

DF Aerial; Groundboom 0.024 Y

Y

N rate. 

Citrus (calamondin, 

citron, chironja, tangelo, 

tangot, grapefruit, 

kumquat, lemon, lime, 

mandarin, orange, 

pumello) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.031 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Pome fruits (apple, 

crabapple, loquat, 

mayhaw, pear, quince) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.031 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Stone fruits (apricot, 

cherry, nectarine, peach, 

plum, plumcot, prune) 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.031 Y

Y

N N Flagger p

rate. H

treatm

f

DF Aerial; Groundboom 0.031 Y

Y

N N/A 

Nuts (almond, beech nut, 

brazil nut, butternut, 

cashew, chestnut, 

EC/Liquid Aerial; Groundboom; Handheld equipment 0.031 Y

Y

N N 

Flagger p

rate. H

treatm
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Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

chinquapin, filbert, 

hickory nut, macadamia 

nut, pecan, walnut) DF Aerial; Groundboom 0.031 Y

Y

N N/A 

f

Tropical fruits (acerola, 

atemoya, biriba, black 

sapote, canistel, 

cherimoya, custard apple, 

feijoa, guava, jaboticaba, 

llama, longan, lychee, 

mango, papaya, passion 

fruit, pawpaw, pulasan, 

rambutan, sapodilla, 

soursop Spanish lime, 

star apple, sugar apple, 

wax jambu) 

EC/Liquid Aerial; Groundboom 0.031 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.031 Y

Y

N

Banana EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Cacao EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Cocoa beans EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

rate. 

Coconut EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Coffee EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Date EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Fig EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Guayule EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Indian Mulberry EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Kiwi EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

Olive EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Palm heart EC/Liquid Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Persimmon EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Pomegranate EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Tea EC/Liquid Aerial; Groundboom 0.0625 Y

Y

N N/A Flagger p

DF Aerial; Groundboom 0.031 Y

Y

N rate. 

Vanilla DF Aerial; Groundboom 0.031 Y

Y

N N/A Flagger p

rate. 

Potato 

EC/Liquid Aerial; Groundboom 0.09 

N

N

N

N/A 

Higher r

assessed. 

lb ai/A r

DF Aerial; Groundboom 0.09 

N

N

N

Vegetable, root and 

tuber; tuberous and corm 

(beets, carrots, ginger, 

horseradish, parsnip, 

radish, sugar beets, yams, 

sweet potatoes, turnips) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Vegetable, leaves of root 

and tuber (beets, carrots, 

radish, sugar beets, 

turnip tops, chicory) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Vegetable, bulb (chive, 

dry bulb onions, garlic, 

onions, leek, scallions, 

shallots) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Vegetable, leafy 

(arugula, celery, celeriac, 

cress, endive, fennel, 

lettuce, parsley, purslane, 

rhubarb, spinach, 

radicchio, Swiss chard) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N
Carfentrazone Human-Health Assessment Scoping Document D382666 

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Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

Vegetable, Brassica

(broccoli, Brussels 

sprout, cabbage, Chinese 

cabbage, cauliflower, 

collards, kale, kohlrabi, 

greens, mustard greens, 

mustard spinach, rape 

greens) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Vegetable, legume (black 

eyed peas, chick pea, 

edible peas, endamame, 

kidney beans, lentil, lima 

beans, pinto beans, snap 

beans, succulent shelled 

peas, wax beans) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Vegetables, foliage of 

legume (beans, cowpeas, 

catjang, endamame, guar, 

lentil, lupin, peas) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Vegetable, fruiting 

(eggplant, groundcherry, 

pepino, pepper, 

tomatillo, tomato) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Vegetable, cucurbit 

(cucumber, cantaloupe, 

melons, gherkin, gourd, 

pumpkin, summer and 

winter squash, 

watermelon) 

EC/Liquid Aerial; Groundboom 0.064 Y

Y

N

N/A Flagger p

rate. 

DF Aerial; Groundboom 0.064 Y

Y

N

Aquatic sites EC/Liquid 

Aerial; Boat-mounted 

boom; Handheld 

equipment 

0.2 lb ai/A or 

0.54 lb ai/Aft 

N

N

N

N Higher ac

use sites 

Site preparation EC/Liquid Aerial; Groundboom; Handheld equipment 0.09 

N

N

N

N Higher ap

h

Airports EC/Liquid Groundboom; Handheld equipment 0.09 N 

Y N/A 

N Labels in

edge arou
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 36 of 39 

Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

Buffer strips EC/Liquid Groundboom; Handheld equipment 0.04 Y Y N/A 

N non-cr

applicat

certain 

allowed 

Conservation reserve 

program EC/Liquid Groundboom; Handheld equipment 0.04 Y Y N/A 

N

Golf courses 

EC/Liquid 

Groundboom; Handheld 

equipment 

0.09 N 

Y N/A 

N

DF (water 

soluble 

bags) 

0.12 N Y N/A N 

Habitat Restoration and 

Management Areas EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Highways and Roadsides EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Industrial Plant Sites EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Lumberyards EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Mine reclamation project 

sites EC/Liquid Groundboom; Handheld equipment 0.04 

N

Y N/A 

N

Parking Areas EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Pavement cracks EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Parks EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Residential, commercial, 

and public landscapes EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Petroleum tank farms EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Pipeline, power, 

telephone and utility 

ROW 

EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Pumping installations EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Railroads EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 37 of 39 

Table 10. Summary of Registered Occupational Use Patterns, Formulations and Maximum Application Rates for Carfentrazone-ethyl.

Crop / Use Site Formula- tion Application Equipment Maximum application rate (lb ai/A) Scenario Covered? 

Mixer/ 

loader Applicator Flagger 

Mixer/ 

loader/ 

applicator 

Schools EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Storage areas EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Electrical substations EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Fencerows EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Edge of landscape beds EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Farmyards EC/Liquid Groundboom; Handheld equipment 0.04 Y

Y N/A 

N

Turfgrass renovation 

(excluding commercial 

sod farms) 

EC/Liquid Groundboom; Handheld equipment 0.09 

N

Y N/A 

N

Sod production EC/Liquid Groundboom; Handheld equipment 0.04 Y

Y N/A 

N

Container and Field 

grown ornamentals EC/liquid Groundboom; Handheld equipment 0.04 Y Y N/A N Handheld 

Christmas tree farms EC/liquid Groundboom; Handheld equipment 0.04 Y Y N/A N Handheld 

Ornamental Lawns and 

Turf DF Groundboom; Handheld equipment 0.04 Y Y N/A N 

Higher un

scenario 

Other h

Residential lawns 

DF Handheld equipment 0.03 N/A N/A N/A N Handheld 

Liquid 

Handheld equipment 0.04 N/A N/A N/A N RTU Trigger-pump 0.015 N/A N/A N/A N 

a. DF = dry flowable; EC = emulsifiable concentrate b. N/A = not applicable; Y = yes; N = no; M/L/A = mixer/loader/applicator 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 38 of 39 

Attachment 9: DCI Table

Guideline Number: 870.7800

Study Title: Immunotoxicity

Rationale for Requiring the Data

This is a new data requirement under 40 CFR Part 158 as a part of the data requirements for 

registration of a pesticide (food and non-food uses). 

The Immunotoxicity Test Guideline (OPPTS 870.7800) prescribes functional immunotoxicity 

testing and is designed to evaluate the potential of a repeated chemical exposure to produce 

adverse effects (i.e., suppression) on the immune system. Immunosuppression is a deficit in the 

ability of the immune system to respond to a challenge of bacterial or viral infections such as 

tuberculosis (TB), Severe Acquired Respiratory Syndrome (SARS), or neoplasia. Because the 

immune system is highly complex, studies assessing functional immunotoxic endpoints are 

helpful in fully characterizing a pesticide’s potential immunotoxicity. These data will be used 

in combination with data from hematology, lymphoid organ weights, and histopathology in 

routine chronic or subchronic toxicity studies to characterize potential immunotoxic effects. 

Practical Utility of the Data

How will the data be used?

These animal studies can be used to select endpoints and doses for use in risk assessment of all 

exposure scenarios and are considered a primary data source for reliable reference dose 

calculation. For example, animal studies have demonstrated that immunotoxicity in rodents is 

one of the more sensitive manifestations of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) among 

developmental, reproductive, and endocrinologic toxicities. Additionally, the EPA has 

established an oral reference dose (RfD) for tributyltin oxide (TBTO) based on observed 

immunotoxicity in animal studies (IRIS, 1997). 

How could the data impact the Agency's future decision-making?

If the immunotoxicity study shows that the test material poses either a greater or a diminished 

risk than that given in the interim decision’s conclusion, the risk assessments for the test 

material may need to be revised to reflect the magnitude of potential risk derived from the new 

data. 

 

If the Agency does not have this data, a 10X database uncertainty factor may be applied for 

conducting a risk assessment from the available studies. 
Carfentrazone Human-Health Assessment Scoping Document D382666 

Page 39 of 39 

Guideline Number: 870.3465 

Study Title: 28-Day Inhalation Toxicity Study

Rationale for Requiring the Data 

The HED HIARC requested a 28-day inhalation toxicity study as a condition of registration. 

However, based on low volatility and low inhalation toxicity (Toxicity Category IV) for 

carfentrazone-ethyl and since the inhalation margins of exposure (MOEs) were >1,000, a waiver 

of the 28-day inhalation toxicity study was deemed acceptable [HED Standard Operating 

Procedure (SOP) 2002.01: Guidance: Waiver Criteria for Multiple-Exposure Inhalation Toxicity 

Studies, 15-Aug-2002]. However, the Agency is currently reevaluating the inhalation 

waiver criteria and based on this analysis, an inhalation study may be required in the 

future. 

Practical Utility of the Data 

How will the data be used? 

Repeated-exposure inhalation toxicity studies provide critical scientific information needed to 

characterize potential hazard to the human population on the effects of a pesticide from 

inhalation exposure. Since epidemiologic data on the effects of inhalation exposure to 

chlorfenapyr are unavailable and therefore inadequate to characterize a pesticide’s potential 

effects in humans, animal studies are used as the most sensitive endpoint for risk assessment. 

These animal studies can be used to select endpoints and doses for use in risk assessment of all 

exposure scenarios and are considered a primary data source for reliable reference dose 

calculation. 

How could the data impact the Agency's future decision-making? 

If the inhalation study shows that the test material poses either a greater or a diminished risk 

than that using the biomonitoring data in conjunction with the oral endpoint, then the risk 

assessments for the test material may need to be revised to reflect the magnitude of potential risk 

derived from the new data. If the Agency does not have this data, a 10X database uncertainty 

factor may be applied for conducting a risk assesment from the available studies.