Clopyralid Registration Review Human Health Scoping Document D416096

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Executive Summary

The Health Effects Division (HED) Clopyralid Registration Review Team has evaluated the 

status of the human health risk assessment for clopyralid to determine the scope of work 

necessary to support Registration Review. This scoping exercise is based primarily on the most 

recently completed human health risk assessment (Dotson et al. 6 June 2012, D391397) to 

support uses on apples, teff, Brassica leafy greens, and rapeseed. 

Based on the currently registered uses, exposures to clopyralid can be expected to occur via the 

dietary (food and drinking water), occupational (handler and post-application), and residential 

(handler and post-application) exposure pathways through oral, dermal, and/or inhalation routes 

of exposure.

Clopyralid is an herbicide belonging to both the picolinic acid and pyridine chemical groups. It

is used to control broadleaf weeds. It is structurally similar to plant auxins and acts as an “auxin 

imitator,” disrupting plant growth by binding to auxin receptors. Clopyralid is registered for use 

on a variety of food/feed crops and on turf in the U.S. for the postemergence control of broadleaf 

weeds, particularly thistles and clover. The mammalian mode of action is unknown.

The toxicology database for clopyralid is considered complete and no additional studies are 

required. Endpoints have been selected for assessing chronic dietary exposure, inhalation 

exposure, and incidental oral exposure. An endpoint for assessing a single oral exposure was not 

identified and an acute reference dose (RfD) was not selected. The available toxicology studies 

did not indicate the potential for neurotoxicity, immunotoxicity, or reproductive toxicity, and 

there is no evidence of increased qualitative or quantitative susceptibility of fetuses or offspring 

in developmental and reproduction studies. Additionally, the exposure estimates were based on 

conservative assumptions. Therefore, HED reduced the required 10x Food Quality Protection 

Act (FQPA) Safety Factor to 1x. Clopyralid is classified as “not likely to be carcinogenic to 

humans.” During registration review, no major changes are expected for the toxicology 

database, endpoint and dose selection or uncertainty factors.

The residue chemistry database is complete; the metabolism of clopyralid in crops and livestock 

is adequately understood and the tolerances are supported by adequate data. Adequate

enforcement methods are available for crop and livestock commodities. The tolerance 

expression [40 CFR 180.431] is in accord with current policy, containing coverage and 

compliance statements, and does not need to be revised during registration review. U.S. 

tolerances are generally harmonized with Canadian MRLs, with the exception of livestock 

commodities and a few crops. Harmonization may be possible during registration review. There 

are no new residue chemistry data needed to support dietary exposure assessment for clopyralid. 

HED expects to complete a new dietary exposure assessment during registration review in order 

to address new EDWCs. 

The residential exposure database is complete; registered residential uses have been assessed in 

accordance with the updated (2012) Residential SOPs, and there were no risks of concern. 

Additional work to assess residential exposure and risk is not expected under registration review. 
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Provided there are no changes to the residue estimates for drinking water, an updated aggregate 

risk assessment is not likely to be required to support registration review. 

The occupational exposure database is complete. Additional work to assess occupational 

exposure and risk is not expected under registration review.

Product labels which contain the monoethanolamine salt of clopyralid acid specify a restrictedentry interval (REI) of 12 hours. However, the acid form of clopyralid is classified as Toxicity 

Category I for eye irritation. Therefore, all products containing the acid form of clopyralid 

should, according to the Worker Protection Standard guidelines, have an REI of 48 hours. HED 

recommends that PRD ensure that the appropriate REI is provided on product labels.

Introduction

HED has evaluated the most recent complete human health risk assessment for clopyralid

conducted in 2012, as well as older evaluations, to determine any outstanding data requirements 

or additional data required to complete registration review for this herbicide. HED has also 

considered updates to its toxicity, exposure and usage databases, and the latest Agency science 

policy and risk assessment methodologies.

Clopyralid is a pyridinoxy acid herbicide registered for use on a variety of field, fruit, and 

vegetable crops in agricultural settings. For non-crop uses, clopyralid is registered for 

application to pastures and rangeland, rights-of-way, forestry sites, tree plantations, ornamental 

grasses in landscapes and nurseries, and nonresidential turf grass (including golf courses and 

recreational areas). Clopyralid is not registered for use on residential turf/lawns. Registered 

formulations containing clopyralid as an active ingredient include liquids, granules, and waterdispersible granules. In those formulations, clopyralid may be in the form of organic (e.g., 

monoethanolamine, triethanolamine) or inorganic (e.g., potassium) salts.

Information on the chemical identity of clopyralid is included in Attachment 1.

Hazard Identification/Toxicology

The toxicology database for clopyralid is considered complete. Available studies include a 21-

day dermal toxicity study in the rabbit and the following oral studies: a subchronic toxicity in 

the mouse, chronic toxicity in the dog, chronic toxicity/carcinogenicity in the rat, carcinogenicity 

in the mouse, prenatal toxicity in the rat and rabbit, reproductive toxicity in the rat, metabolism 

in the rat, and immunotoxicity in the rat. In addition, there is a complete battery of genotoxicity 

studies. Subchronic studies for rats and dogs are not available; however, requirements for these 

studies were satisfied by the chronic toxicity studies. Acute and subchronic neurotoxicity studies 

in the rat are not available; however, HED’s Hazard and Science Policy Council (HASPOC) 

concluded that these studies are not required based on the lack of evidence of neurotoxicity in the 

available studies conducted with clopyralid as well as with other structurally related compounds

(TXR#0056270). In addition, based on similar weight of evidence considerations, a 

developmental neurotoxicity study is not required for clopyralid. HASPOC also determined that 
Clopyralid Registration Review Human Health Scoping Document D416096

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a 28-day inhalation toxicity study in the rat (§870.3465) is not required. Although there are data 

to indicate potential irritation portal of entry effects for the respiratory tract (based on gastric 

lesions in some oral studies and severe primary eye irritation), the current MOEs are high, and 

are more than 100-fold higher than the level of concern for all residential scenarios and all but 

one occupational exposure scenario. Additionally, clopyralid has low volatility, low acute 

inhalation toxicity, and the points of departure selected from oral studies are sufficiently 

conservative to allow for uncertainties associated with route-to-route extrapolation for inhalation 

risk assessment.

Toxicity was observed in the rat and dog following chronic exposure, but consistent target 

organs were not identified. In a one-year dog study, reductions in red blood cell parameters, 

increased liver weight (males), and vacuolated adrenal cortical cells (females) were reported. 

Skin lesions and clinical chemistry changes (decreased serum glucose, protein, albumin) were 

observed at the highest dose. In the rat, epithelial hyperplasia and thickening of the limiting 

ridge of the stomach were observed at the LOAEL, and decreased body weight was observed at 

the highest dose. Only decreased body weight/weight gain and food efficiency in males were 

observed in the mouse carcinogenicity study at doses exceeding the limit dose. Subchronic data 

were available only for the mouse, where decreased body weight was observed in a 90-day oral 

study in males and females at dietary levels exceeding the limit dose (1000 mg/kg/day). No 

systemic toxicity was observed in rabbits following dermal exposure up to the limit dose for 21 

days. A rat immunotoxicity study showed no treatment-related effects on the immune system, 

and immunotoxicity was also not observed in other studies. 

There was no indication of increased qualitative or quantitative pre- and/or postnatal 

susceptibility. No developmental toxicity was observed in the rat at doses that caused maternal 

mortality and decreased maternal body weight gain. Decreased fetal body weight and 

hydrocephalus were observed in the rabbit but only at a dose that caused significant maternal 

toxicity including mortality, clinical signs of toxicity, decreased body weight gain, and gastric 

mucosal lesions. Reproductive toxicity was not observed in the rat, but mean pup weights (Day 

28) were reduced, and relative liver weights were increased at doses that caused parental toxicity 

(decreased body weight/weight gain and food consumption; gastric lesions).

There were no direct clinical or histopathological indications of neurotoxicity in the available 

studies at doses up to or exceeding the limit dose. Hydrocephalus was observed in the young in 

the rabbit developmental study in the presence of significant maternal toxicity, including a high 

rate of mortality. However, no indications of neurotoxicity were observed in maternal animals at 

the same dose, in other species, or in studies on other structurally related chemicals. Therefore, 

acute, subchronic, and developmental neurotoxicity studies in the rat are not required based on 

lack of evidence of neurotoxicity for clopyralid and related chemicals. 

Clopyralid is classified as “not likely to be carcinogenic to humans.” No evidence of 

carcinogenicity was observed in rat and mouse 2-year bioassays at doses exceeding the limit 

dose. No positive findings for mutagenicity or clastogenicity were observed in a battery of 

mutagenicity studies. An acceptable metabolism study in rats indicated clopyralid was 

essentially completely absorbed at both low and high doses, with no significant differences in 

metabolism between males and females, or between dose groups. Excretion was primarily via 
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the urine, and no radioactivity was retained in tissues. There was no evidence of metabolism; 

only parent compound was identified in the urine and feces.

The acute toxicity of clopyralid is low (Toxicity Category III or IV) via oral, inhalation and 

dermal exposure, and it is not a dermal irritant or sensitizer. However, in its acid form, 

clopyralid is a severe eye irritant (Category I).

Based on the existing use patterns and the submitted toxicology studies, HED selected endpoints 

for assessment of human health risk for chronic dietary exposure, residential incidental oral 

exposure, and occupational and residential inhalation exposure. For acute dietary exposure, an 

endpoint resulting from a single exposure was not identified. As a result, an aRfD was not 

determined. The finding of hydrocephalus in the young in the rabbit developmental study was 

not considered to be an appropriate endpoint because it was observed only at the highest dose 

tested in the presence of severe maternal toxicity, including a high rate of mortality.

For chronic dietary exposure, the NOAEL of 15 mg/kg/day from the rat chronic 

toxicity/carcinogenicity study was selected, based on increased epithelial hyperplasia and 

thickening of the limiting ridge of the stomach in both sexes at the LOAEL of 150 mg/kg/day. 

For short-term incidental oral exposure as well as short-term inhalation exposure, the maternal 

toxicity NOAEL of 75 mg/kg/day from the rat developmental toxicity study was selected based 

on mortality, decreased maternal body weight gain, and decreased food consumption at the 

LOAEL of 250 mg/kg/day.

For intermediate-term inhalation exposure, the NOAEL of 15 mg/kg/day from the rat dietary 

chronic toxicity/carcinogenicity study was selected based on increased epithelial hyperplasia and 

thickening of the limiting ridge of the stomach in both sexes at the LOAEL of 150 mg/kg/day. 

Although it is of chronic duration, it was selected to be protective of gastric irritation that might 

result from oral exposure of intermediate duration, and is considered to be a conservative 

endpoint for this exposure scenario.

Quantification of dermal risk is not required due to lack of dermal or systemic toxicity following 

repeated dermal applications at the Limit Dose (1000 mg/kg/day) in a 21-day dermal toxicity 

study and there are no developmental or reproductive concerns.

Conclusions for Hazard Identification/Toxicology

The toxicology database for clopyralid is complete and there are no additional studies required. 

In the absence of additional data, HED does not anticipate revising the regulatory endpoints, 

points of departure (PoDs) and uncertainty factors/safety factors (UF/SFs) during registration 

review.

Residue Chemistry and Dietary Exposure

The residue chemistry database for clopyralid is complete and adequate to support dietary 

exposure and risk assessment based on exposure through food and drinking water.
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The nature of the residue in plants and livestock is adequately understood. Parent compound is 

the only major residue in plants; in livestock, the major residues are the parent clopyralid and its 

glycine conjugate (3,6-DCPA-glycine). The residue definition for enforcement for plants and 

livestock is clopyralid. For risk assessment, the residue definitions are clopyralid in plants and

combined residues of clopyralid and 3,6-DCPA-glycine (expressed as clopyralid) in livestock.

Adequate analytical methods for enforcing tolerances in plant and livestock matrices are

available. The FDA multiresidue methods are not likely to recover clopyralid; however, it does 

appear to be adequately recovered by the “QuEChERS” multiresidue method 

(http://www.quechers.com).

Field trial data generated using acceptable data collection methods and supported by adequate 

storage stability data are available for all registered crops. Adequate processing studies are 

available. Adequate livestock feeding studies have been submitted for clopyralid. Tolerances in 

crops and livestock range from 0.05 to 500 ppm and are based on quantifiable residues.

A drinking water assessment (D391398, W. Shaughnessy, 19 December 2011) was conducted by

the Environmental Fate and Effects Division (EFED) for clopyralid. EFED has determined that 

the most recent drinking water assessment does not reflect the highest use rate for clopyralid; 

therefore, new EDWCs will be provided during registration review.

The most recent dietary risk estimates for clopyralid are below HED’s level of concern 

(D399390, D. Dotson, 6 June 2012). There is no acute dietary endpoint for clopyralid; therefore, 

acute dietary risk is not a concern for this chemical. A chronic dietary (food + drinking water) 

exposure and risk assessment was conducted for clopyralid using the Dietary Exposure 

Evaluation Model DEEM-FCIDTM, Version 2.03 which uses food consumption data from the 

U.S. Department of Agriculture’s Continuing Surveys of Food Intakes by Individuals (CSFII) 

from 1994-1996 and 1998. The assessment is highly conservative because it is based on 

tolerance-level residues and the assumption of 100% crop treated for all included commodities. 

DEEM Version 7.81 default processing factors were used for all processed commodities for 

which they were available. Clopyralid is classified as “not likely to be carcinogenic to humans.” 

As a result, cancer risk is not an issue for this chemical. The most recent dietary risk estimates 

for clopyralid were below HED’s level of concern for all population subgroups (maximum risk 

estimate was 25% cPAD for children 1-2 years old). As noted above, EFED will be providing 

HED with new EDWCs for clopyralid; therefore, HED will conduct a new dietary assessment 

during registration review.

Conclusions for Residue Chemistry/Dietary Exposure and Risk

The residue chemistry database is complete and adequate for the purpose of tolerance-setting and 

dietary risk assessment. HED expects to conduct a new dietary risk assessment with up-to-date 

EDWCs during registration review; additional work related to residue chemistry is not expected.
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Residential Exposure and Risk

Handler Exposure

Clopyralid and its associated salts are registered for use on non-residential turf, golf courses, 

athletic and recreational fields, ornamentals grasses, and landscapes. Since clopyralid is not a 

restricted-use pesticide, HED conducted a residential handler exposure assessment to be 

protective of potential homeowner exposure and for the purpose of conducting an aggregate risk 

assessment. 

The primary source of information used to evaluate residential handler exposure was the most 

recent clopyralid residential exposure assessment (D391748, S. Oonnithan, 30 April 2012). This 

review assessed residential handler short-term inhalation exposure resulting from use of handheld equipment (i.e., hose-end, back-pack, manually pressurized handwand sprayers and pushtype spreader) for both liquid and granular formulations using the 2012 Residential Standard 

Operating Procedures (SOPs). Residential handler MOEs ranged from 340,000 to 24,000,000 

and are not of concern.

It should be noted that the product (Reg. No. 62719-263) assessed for the granular formulation 

mentioned above was cancelled on September 12, 2012. HED performed a preliminary screen of 

several other granular lawn products containing clopyralid to determine whether there were 

additional products that could result in higher risks of concern. These granular products 

(Conditional Reg. Nos. 228-343, 961-390, and 961-39) all have lower application rates than the 

assessed product. Therefore risk estimates for those products would be less than the risks

presented in the 2012 assessment. 

Post-application Exposure

A post-application incidental oral exposure assessment for children playing on treated lawns was 

conducted for both liquid and granular formulations. Quantitative dermal and inhalation postapplication exposure and risk assessments were not conducted in the previous assessment due to 

the lack of hazard via the dermal and inhalation routes. Post-application MOEs ranged from 

10,000 to 4,600,000 and are not of concern.

In accordance with the updated Part 158 data requirements (2007), a turf transferrable residue 

(TTR) study is required for all residential or occupational turf uses (e.g., sod farms, golf courses, 

parks, and recreational areas). However, a TTR study is not required for clopyralid at this time 

because post-application incidental oral exposure calculated previously resulted in MOEs at least 

10 times higher than the level of concern (e.g., an MOE> 1,000 if the LOC = 100); therefore, 

using the default residue transfer values should provide an adequate margin of safety for any 

potentially higher residues seen in a chemical-specific TTR study.

Spray Drift and Volatilization

Residential exposures resulting from off-site transport (e.g., spray drift or volatilization) might 

occur as a result of applications of clopyralid. The Agency is in the process of evaluating these 

types of exposures and might, as appropriate, develop policies and procedures to identify the 

need for and, subsequently, the way to incorporate these post-application exposures into the 
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Agency’s risk assessments. The need for spray drift and volatilization risk assessment for 

clopyralid will be examined during registration review.

Conclusions for Residential Exposure and Risk

All residential risk estimates are in accord with current policies and practices for residential 

assessment. The risk estimates are below HED’s level of concern and no additional residential 

exposure and risk assessments are anticipated during registration review.

Aggregate Risk Assessment

The most recently completed aggregate risk assessment was conducted in connection with 

requested new uses on apples, teff, Brassica leafy greens, and rapeseed. Aggregate risk 

estimates, which included exposure from food, drinking water, and recreational turf grass 

sources, were below HED’s level of concern for all groups and exposure durations. HED will be 

conducting a new dietary assessment during registration review to address updated EDWCs for 

clopyralid. Depending on the results of that assessment relative to current dietary exposure 

estimates, HED may need to conduct an updated aggregate risk assessment to support 

registration review.

Occupational Exposure

Occupational and commercial handler assessments are based only on inhalation exposures, 

because clopyralid does not cause systemic toxicity via the dermal route. The primary source of 

information used to evaluate occupational handler and post-application exposure was the most 

recent clopyralid occupational exposure assessment (D391748, S. Oonnithan, 30 April 2012). 

Occupational Handler Exposure

The registrant has not submitted chemical-specific exposure data to estimate handler exposures. 

In the absence of chemical-specific data, it is HED policy to use the best available data to assess 

handler exposures. Sources of such generic (surrogate) handler data include the Pesticide 

Handlers Exposure Database Version 1.1 (PHED 1.1) and the Agricultural Handler Exposure 

Task Force (AHETF) database, or other registrant-submitted occupational exposure studies. 

Some of these data are proprietary (e.g., AHETF data) and subject to the data protection 

provisions of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The standard 

values recommended for use in predicting handler exposure that are used in this assessment, 

known as “unit exposures,” are outlined in the “Occupational Pesticide Handler Unit Exposure 

Surrogate Reference Table1

.” That table, along with additional information on the HED policy 

addressing the use of surrogate data, including descriptions of the various sources, can be found 

at the Agency website2. 

End use products containing clopyralid and its associated salts are formulated as liquids, 

granules, and water dispersible granules (WDG). They may be applied as a broadcast foliar or 

soil directed spray by ground, aerial, hand held equipment, granular spreader and/or tree 

 1 Available: http://www.epa.gov/opp00001/science/handler-exposure-table.pdf 2 Available: http://www.epa.gov/pesticides/science/handler-exposure-data.html
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injection. The 2012 occupational exposure review assessed occupational and commercial 

handler short-and intermediate-term inhalation exposure resulting from the use of one product 

formulated as an emulsifiable concentrate (EC) applied by ground and hand-held equipment 

only. These scenarios incorporate revised unit-exposure values and body weights, and resulted 

in risk estimates which were not of concern at baseline level of personal protective equipment 

(PPE) consisting of long-sleeved shirt, long pants, socks and shoes. However, the EC 

formulation is not representative of the worst-case scenario for exposure. Therefore, HED 

performed a preliminary screen of several WDG products (Reg. Nos. 62719-315 and 352-593) 

containing clopyralid and its associated salts with the same application rate as the EC 

formulation product assessed in 2012, using the most current unit exposure and body weight

estimates . Although the WDG inhalation post-application exposure risk estimates resulted in 

more exposure than those calculated for the EC formulation, all risk estimates were significantly 

greater than the level of concern (LOC = MOE > 100) and did not result in risks of concern. No 

additional occupational uses need to be re-evaluated during registration review. 

Product labels which contain the monoethanolamine salt of clopyralid acid specify a restrictedentry interval (REI) of 12 hours. However, the acid form of clopyralid is classified as Toxicity 

Category I for eye irritation. Therefore, all products containing the acid form of clopyralid 

should, according to the Worker Protection Standard guidelines, have an REI of 48 hours.

Occupational Post-application Exposure

A quantitative dermal post-application exposure assessment was not completed for the 

agricultural and non-agricultural uses of clopyralid due to the lack of dermal toxicity. 

Chemical-specific dislodgeable foliar residue (DFR) and turf transferable residue (TTR) data 

have not been submitted. These data are not needed for clopyralid due to the lack of an endpoint 

for dermal risk assessment. During registration review, HED will consider the impact of new 

policies and procedures, such as addressing volatilization exposure, as well as the potential for 

exposure from spray drift. However, no risk issues are expected and no additional data are 

needed at this time.

A quantitative post-application inhalation exposure assessment was not performed for clopyralid 

based on the Agency's current practices. However, there are potential sources of inhalation 

exposure to workers performing post-application activities in previously treated fields. These 

potential sources include volatilization of pesticides and re-suspension of dusts and/or 

particulates that contain pesticides. The Agency sought expert advice and input on issues related 

to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act 

Scientific Advisory Panel (SAP) in December 2009, and 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 post-application 

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 clopyralid.
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The technical clopyralid acid is classified as Toxicity Category I for severe eye irritation. In 

accordance with the Worker Protection Standard (WPS) guidelines, the label for a product that 

contains an active ingredient which is classified as Toxicity Category I must include appropriate 

PPE (in this case, protective eyewear) and specify an REI of not less than 48 hours. Some enduse products containing clopyralid specify an REI of 12 hours. Discrepancies between PPE and 

REI to avoid potential eye injury to all post-application workers will need to be resolved during 

registration review.

Conclusions for Occupational Exposure and Risk

No chemical-specific data, such as dislodgeable foliar residue (DFR) and turf transferable 

residue (TTR) data, are required to support registration review for clopyralid due to the lack of 

an endpoint for dermal risk assessment. During registration review, HED will consider the 

impact of new policies and procedures, such as addressing volatilization exposure, as well as the 

potential for exposure from spray drift. However, no risk issues are expected and no additional 

data are needed at this time.

Public Health and Pesticide Epidemiology Data

The Agency has reviewed the available incident data for clopyralid (D416106, E. Evans and S. 

Recore, 20 November 2013) and concludes that based on the low frequency and generally low 

severity of incident cases reported for clopyralid, 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

Tolerances for clopyralid are established under 40 CFR §180.431 for residues of the herbicide 

from applications in the acid form or from application of its salts. The tolerance listing is in 

accordance with current language and specifies that for plant and livestock commodities, 

compliance with the tolerance levels shall be determined by measuring only clopyralid.

There are no Codex Maximum Residue Limits (MRLs) established for residues of clopyralid at 

this time. Canadian MRLs exist for many commodities with U.S. tolerances, and the residue 

definitions are the same for the U.S. and Canada. For commodities with listings in each country,

U.S. tolerances are generally harmonized with Canadian MRLs for plant commodities; however, 

U.S. tolerances and Canadian MRLs for livestock commodities are not harmonized. For plant 

commodities, the following limits are not harmonized: blueberry, strawberry, and processed 

commodities of barley, oat, and wheat. During registration review, HED will examine the basis 

for the U.S. tolerances and, to the extent possible, harmonize with Canadian MRLs for plant and 

livestock commodities. The International Residue Limit Status Sheet is attached to this 

document as Attachment 4. 

There are no pending requests for the establishment of new tolerances for clopyralid.
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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.eh.doe.gov/nepa/tools/guidance/Volume1/2-6-EO_12898envjustice.pdf). The Office 

of Pesticide Programs (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.

Cumulative

EPA has not, at this time, made a determination as to whether clopyralid shares a common 

mechanism of toxicity with any other substances. 

Human Studies

Past clopyralid 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. 

These data, which include studies from the Pesticide Handlers Exposure Database Version 1.1 

(PHED 1.1); the Outdoor Residential Exposure Task Force (ORETF) database; the Agricultural 

Re-entry Task Force (ARTF) database; and other registrant-submitted exposure monitoring 

studies, are subject to ethics review pursuant to 40 CFR 26, have received that review, and are 

compliant with applicable ethics requirements. For certain studies that review may have 

included review by the Human Studies Review Board. Descriptions of data sources as well as 

guidance on their use can be found at http://www.epa.gov/pesticides/science/handler-exposuredata.html and http://www.epa.gov/pesticides/science/post-app-exposure-data.html.

Data Requirements

None

References

Table 1: HED Memoranda Relevant to Registration Review

Author Barcode/ TXR 

#

Date Title

Dotson, D., 

Hansen, L., 

Oonnithan, S

D391397, 

D401055

6 June 2012 Clopyralid. Human Health Risk 

Assessment for New Uses on 

Apples, Teff, Brassica Leafy 

Greens, and Rapeseed
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Table 1: HED Memoranda Relevant to Registration Review

Author Barcode/ TXR 

#

Date Title

Rury, K. TXR#0056270 29 March 2012 Clopyralid: Summary of Hazard 

and Science Policy Council 

(HASPOC) Meeting of March 29, 

2012: Recommendation on the 

need for 28-day inhalation and 

acute/subchronic neurotoxicity 

studies in the rat and for a turf 

transferable residue study

Shaughnessy, W. D391398 19 December 2011 Tier I Drinking Water Assessment 

for Proposed New Use of 

Clopyralid on Apple, Leafy 

Brassica Greens Subgroup 5B, and 

Rapeseed Subgroup 20A, Except 

Camelina (Gold of Pleasure)

Dotson, D. D399390 6 June 2012 Clopyralid Chronic Aggregate 

Dietary (Food and Drinking Water) 

Exposure and Risk Assessment for 

the Section 3 Registration Action on 

Apples, Teff, the Leafy Brassica 

Greens Subgroup (5-B), and the 

Rapeseed Subgroup (20-A)

Oonnithan, S. D391748 30 April 2012 Clopyralid: Occupational Exposure 

Assessment for a New Use on 

Apples; Expansion of Crop Group 

5B; and Revised Residential 

Exposure Assessment for use on 

Turf

Evans, E. and 

Recore, S.

D416106 20 November 2014 Clopyralid: Tier I Review of 

Human Incidents

Attachments

Attachment 1. Chemical Identity

Attachment 2. Toxicity Profile Tables

Attachment 3. Endpoint Tables

Attachment 4. International Residue Limits Table

Attachment 5. Summary of End-Use Products Containing Clopyralid
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Attachment 1. Clopyralid Chemical Identity

Table A.1.1. Clopyralid Nomenclature

Compound

Common Name Clopyralid Acid

Company Experimental 

Name

Dowco 290

IUPAC Name 3,6-dichloropyridine-2-carboxylic acid

CAS Name 3,6-dichloro-2-pyridinecarboxylic acid

CAS Registry Number 1702-17-6 (acid)

Table A.1.2. Physicochemical Properties of the Technical Grade Clopyralid

Parameter Value References

Physical State Solid A world Compendium, 

The Pesticide Manual, 

14th Edition. C.D. S 

Tomlin (Editor), 2006.

Color Colorless

Melting Point/Range 151-152°C

Dissociation Constant (pKa) 2

Density at 20°C 1.57 g/cm3 

Vapor Pressure at 25°C 1.0 x 10-5 mm Hg (1.33 mPa)

Water Solubility at 20°C 7.85 g/L

Solvent solubility (g/L) at 20°C Acetone: 250

Ethyl acetate: 102

Xylene: 4.6

Hexane: 6.0

Octanol/water partition coefficient, 

Log (KOW)

-1.81 (pH 5) 

-2.63 (pH 7) 

-2.55 (pH 9)
Clopyralid Registration Review Human Health Scoping Document D416096

Page 14 of 32

Attachment 2. Toxicity Profile Tables

Table A.2.1. Acute Toxicity Profile for Clopyralid

Guideline 

Number

Study Type

Classification

MRID

Number

Results Toxicity 

Category

870.1100 Acute-oral-rat 41641301 LD50 (M/F) >5,000 mg/kg IV

870.1200 Acute-dermal-rat 41641302 LD50 (M/F) > 5000 mg/kg IV

870.1300 Acute-inhalation-rat 41848301 LC50 (M/F) > 1 mg/L III

870.2400 Acute-eye irritation-rabbit 41641304 Severe irritation at 7 days (corrosive) I

870.2500 Acute-dermal irritation-rabbit 41641305 Not an irritant IV

870.2600 Skin sensitization - guinea pig 41641306 Not a sensitizer -

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile for Clopyralid

Guideline No. Study Type MRID No. (year)/ 

Classification /Doses

Results

870.3100 90-Day oral 

toxicity (rat)

An acceptable study is not available. Requirement satisfied by combined 

chronic oral toxicity/carcinogenicity study in the rat (870.4300).

870.3100 90-Day oral 

toxicity (mouse) 

00127276 (2003)

Acceptable/guideline

0, 200, 750, 2000 or 5000 

mg/kg/day

NOAEL = 2000 mg/kg/day

LOAEL = 5000 mg/kg/day based on decreased 

body weight gain.

870.3150 90-Day oral 

toxicity (dog)

An acceptable study is not available. Requirement satisfied by chronic oral 

study in the dog (870.4100).

870.3200 21-Day dermal 

toxicity (rabbit)

41790701 (1990)

Acceptable/guideline

0, 100, 500 or 1000 

mg/kg/day

Systemic NOAEL = 1000 mg/kg/day (limit dose)

Systemic LOAEL = not established (>1000 

mg/kg/day).

Local dermal NOAEL < 100 mg/kg/day (LDT)

Local dermal LOAEL = 100 mg/kg/day, based 

on epithelial hyperplasia at application site

870.3250 90-Day dermal 

toxicity 

Study not required.

870.3465 28- Day 

inhalation toxicity 

(rat)

Study not required.

870.3700a Prenatal 

developmental in 

(rat)

00127279 (1981)

Acceptable/guideline

0, 15, 75 or 250 

mg/kg/day

Maternal NOAEL = 75 mg/kg/day

LOAEL = 250 mg/kg/day based on mortality, 

decreased body weight gains and reduced food 

consumption.

Developmental NOAEL = 250 mg/kg/day 

(HDT)

LOAEL = not established (>250 mg/kg/day).

870.3700b Prenatal 

developmental in 

(rabbit)

41649801, -02 (1990)

Acceptable/guideline

0, 50, 110 or 250 

mg/kg/day by gavage

Maternal NOAEL = 110 mg/kg/day

LOAEL = 250 mg/kg/day based on mortality, 

decreased body weight gains, reduced food 

consumption and lesions in the gastric mucosa.

Developmental NOAEL = 110 mg/kg/day

LOAEL = 250 mg/kg/day based on decreased 

fetal body weight and hydrocephalus.
Clopyralid Registration Review Human Health Scoping Document D416096

Page 15 of 32

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile for Clopyralid

Guideline No. Study Type MRID No. (year)/ 

Classification /Doses

Results

870.3800 Reproduction and 

fertility effects

(rat)

00138155 (1983)

Acceptable/guideline

0, 150, 500 or 1500 

mg/kg/day in diet

Parental NOAEL = 500 mg/kg/day

(M/F)

LOAEL = 1500 mg/kg/day(M/F), based on 

decreased body weights and body weight gain in 

F0 and F1 males; body weights in F1 and F2

females

Reproductive NOAEL ≥1500 mg/kg/day

LOAEL = not attained based on lack of effects on 

reproductive parameters (>1500 mg/kg/day)

Offspring NOAEL = 500 mg/kg/day (M/F)

LOAEL = 1500 mg/kg/day (M/F), based on 

decreased Day 28 body weights in F1 male pups 

and increased relative liver weights of F1a male

and female pups and F1b male pups.

870.4100a Chronic toxicity

(rat)

Requirement satisfied by 870.4300.

870.4100b Chronic toxicity 

(dog)

00158256 (1984)

Acceptable/guideline

0, 100, 320 or 1000 

mg/kg/day by capsule

NOAEL = 100 mg/kg/day

LOAEL = 320 mg/kg/day based on decreases in 

RBC parameters, increased liver weight (males) 

and vacuolated adrenal cortical cells (females). 

Clinical chemistry changes (decreased serum 

albumin, globulin, and protein) and skin lesions 

were observed at high dose.

870.4200a Carcinogenicity

(rat)

Requirement satisfied by 870.4300.

870.4200b 24-month 

Carcinogenicity

(mouse)

00162393, 00162434 

(1984)

Acceptable/guideline

0, 100, 500 or 2000 

mg/kg/day in the diet (24 

months)

NOAEL = 500 mg/kg/day

LOAEL = 150 mg/kg/day based on decreased 

body weight/weight gain and reduced food 

efficiency.

No evidence of carcinogenicity

870.4300 Chronic 

toxicity/carcinoge

nicity (rat)

00162393, 00162434 

(1986)

Acceptable/guideline

0, 15, 150 or 1500 

mg/kg/day in the diet 

(104 weeks)

NOAEL = 15 mg/kg/day

LOAEL = 150 mg/kg/day based on gastric lesions 

(epithelial hyperplasia and thickening of the 

limiting ridge). At 1500 mg/kg/day, decreased 

body weight gains and food consumption were 

also observed.

no evidence of carcinogenicity

Gene Mutation

870.5100

Study not submitted. Not required due to lack of tumorigenicity in rat and mouse bioassays and 

negative findings in all other genotoxicity assays, including host-mediated assays in Salmonella

and Saccharomyces.
Clopyralid Registration Review Human Health Scoping Document D416096

Page 16 of 32

Table A.2.2 Subchronic, Chronic and Other Toxicity Profile for Clopyralid

Guideline No. Study Type MRID No. (year)/ 

Classification /Doses

Results

Gene Mutation

870.5300

In Vitro and In 

Vivo Host 

Mediated Assay 

(Salmonella 

strains TA 1530, 

G-46 and 

Saccharomyces

strain D-3) (1973)

In vivo assays 

were conducted 

using mice

00057086 (1973)

Acceptable/guideline

In vitro testing: without 

S9 activation at 5% w/v 

solution

In vivo testing: 0, 4, 40 

or 400 mg/kg by gavage 

to 10 mice

Negative – no evidence of induced mutant 

colonies over background levels in Salmonella or 

Saccharomyces strains tested in either the in vitro

or the in vivo assays.

Cytogenetics

870. 5385

In Vivo

Micronucleus 

assay, Rat

00073638 (1973)

Acceptable/guideline

0, 4, 40 or 400 mg/kg for 

one day or for 5 days to 

male rats; sacrifice at 6, 

24 or 48 hrs postdosing 

for all groups.

Negative – no evidence of an increase in the 

formation of chromosomal aberrations in bone 

marrow at any dose tested. 

Other Effects

870.5450

Dominant Lethal 

Assay in Rats

00059053, 00099100 

(1973)

Acceptable/guideline

4, 40 or 400 mg/kg/day 

for 5 days to male rats 

prior to mating

Negative – no evidence of treatment-related 

resorptions.

Other Effects

870.5550

Unscheduled 

DNA Synthesis, 

Rat Hepatocytes

00156387 (1985), 

41790702 (1990)

Acceptable/guideline

5x10-5, 1.56x10-4, 5x10-4, 

1.56x10-3

, 5x10-3, 

1.56x10-2

, 5x10-2 M, 

incubated for 18-20 hrs

Negative – no evidence of increased unscheduled 

DNA synthesis in the initial or supplementary 

assays testing up to insoluble/toxic 

concentrations.

870.6200a Acute 

neurotoxicity 

screening battery 

(rat)

Study not required.

870.6200b Subchronic 

neurotoxicity 

screening battery 

(rat)

Study not required.

870.6300 Developmental 

neurotoxicity

Study not required.
Clopyralid Registration Review Human Health Scoping Document D416096

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Table A.2.2 Subchronic, Chronic and Other Toxicity Profile for Clopyralid

Guideline No. Study Type MRID No. (year)/ 

Classification /Doses

Results

870.7485 Metabolism and 

pharmacokinetics

(rat)

41790703 (1991)

Acceptable/guideline

5.0 and 50 mg/kg, single 

oral dose; 5.0 mg/kg, 

single IV dose and 5.0 

mg/kg/day, repeated daily 

dose for 14 days

Clopyralid was rapidly and completely absorbed 

and eliminated with 95 to 115% of the 

administered dose recovered by 72 hr, most 

within 6-12 hrs postdosing. Almost all 

radioactivity was eliminated via the urine 

irrespective of dose or route of administration (91 

to 113% of AD), with <4% excreted in the feces. 

Tissue retention was negligible (<0.01% AD). 

There was essentially no metabolism of 

clopyralid: only parent compound was identified. 

No significant gender, dose or exposure route 

differences were identified.

870.7600 Dermal 

penetration 

Study not available.

870.7800 Immunotoxicity 

(rat)

48300001 (2011)

Acceptable/guideline

0, 158, 530, or 1062 

mg/kg/day

Systemic NOAEL = 1062 mg/kg/day (limit dose)

Systemic LOAEL = not established (>1062 

mg/kg/day)

Immunotoxicity NOAEL = 1062 mg/kg/day

Immunotoxicity LOAEL = not established 

(>1062 mg/kg/day)
Clopyralid Registration Review Human Health Scoping Document D416096

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Attachment 3. Summary of Toxicological Dose and Endpoints for Clopyralid

Table A.3.1. Toxicological Doses and Endpoints for Clopyralid for Use in Dietary and Residential Human 

Health Risk Assessments.

Exposure/

Scenario

Point of 

Departure

Uncertainty/FQ

PA Safety 

Factors

Level of 

Concern for 

Risk 

Assessment

Study and Toxicological Effects

Acute Dietary (All 

populations including 

infants and children) 

An appropriate endpoint for a single exposure was not identified.

Chronic Dietary

(All populations

including infants and 

children)

NOAEL= 15 

mg/kg/day

UFA= 10X

UFH= 10X

SFFQPA=1

cRfD=0.15 

mg/kg/day

cPAD=0.15 

mg/kg/day

2-Year Combined Chronic

Toxicity/Carcinogenicity (oral) – rat

LOAEL = 150 mg/kg/day, based on 

increased epithelial hyperplasia and 

thickening of the limiting ridge of the 

stomach in both sexes.

Incidental Oral, Shortterm (1-30 days)NOAEL= 75 

mg/kg/day

UFA= 10X

UFH= 10X

SFFQPA=1

Residential 

LOC for MOE= 

100

Developmental Toxicity (oral) – rat

Maternal LOAEL = 250 mg/kg/day, 

based on decreased body weight gain and 

food consumption during GD 6-9.

Dermal, Short-term

(1-30 days) 

No systemic toxicity was observed up to the limit dose (1000 mg/kg/day) in a rabbit 21-day 

dermal toxicity study and there are no developmental or reproductive concerns.

Inhalation, Short-term

(1-30 days)

Oral study

NOAEL = 75 

mg/kg/day

(inhalation 

toxicity 

assumed to be 

equivalent to 

toxicity via the 

oral route)

UFA= 10X

UFH= 10X

SFFQPA=1

Residential 

LOC for MOE 

= 100

Developmental Toxicity (oral) – rat

Maternal LOAEL = 250 mg/kg/day, 

based on decreased body weight gain and 

food consumption during GD 6-9.

Inhalation Intermediateterm (1-6 months)Oral study 

NOAEL= 15 

mg/kg/day 

(inhalation 

toxicity 

assumed to be 

equivalent to 

toxicity via the 

oral route)

UFA= 10X

UFH= 10X

SFFQPA=1

Residential 

LOC for MOE= 

100

2-Year Combined Chronic

Toxicity/Carcinogenicity (oral) – rat

LOAEL 150 mg/kg/day, based on 

increased epithelial hyperplasia and 

thickening of the limiting ridge of the 

stomach in both sexes.

Cancer (all routes) “Not likely to be carcinogenic to humans.” 

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to 

mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL 

= no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UFA = 

extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity among members of the human 

population (intraspecies). SFFQPA = FQPA Safety Factor. PAD = population adjusted dose (a = acute, c = chronic). RfD = 

reference dose. MOE = margin of exposure. LOC = level of concern. 
Clopyralid Registration Review Human Health Scoping Document D416096

Page 19 of 32

Table A.3.2. Summary of Toxicological Doses and Endpoints for Clopyralid for Use in Occupational Human 

Health Risk Assessments.

Exposure/

Scenario

Point of 

Departure

Uncertainty 

Factors

Level of 

Concern for 

Risk Assessment

Study and Toxicological Effects

Dermal, Short- and 

Intermediate-term (1-30 

days and 1-6 months, 

respectively)

No systemic toxicity was observed up to the limit dose (1000 mg/kg/day) in a 21-day 

dermal toxicity study and there are no developmental or reproductive concerns.

Inhalation, Short-term 

(1-30 days)

NOAEL = 75 

mg/kg/day 

(inhalation 

toxicity 

assumed to be 

equivalent to 

toxicity via the 

oral route)

UFA= 10X

UFH= 10X

Occupational 

LOC for MOE

= 100

Developmental Toxicity (oral) – rat

Maternal LOAEL = 250 mg/kg/day, based 

on decreased body weight gain and food 

consumption during GD 6-9.

Inhalation, Intermediateterm 

(1-6 months)

NOAEL = 15 

mg/kg/day 

(inhalation 

toxicity 

assumed to be 

equivalent to 

toxicity via the 

oral route)

UFA = 10X

UFH = 10X

Occupational 

LOC for MOE

= 100

2-Year Combined Chronic

Toxicity/Carcinogenicity (oral) – rat

LOAEL = 150 mg/kg/day, based on 

increased epithelial hyperplasia and 

thickening of the limiting ridge of the 

stomach in both sexes.

Cancer (all routes) “Not likely to be carcinogenic to humans.” 

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and used to 

mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL 

= no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UFA = 

extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity among members of the human 

population (intraspecies). MOE = margin of exposure. LOC = level of concern. N/A = not applicable. 
Clopyralid Registration Review Human Health Scoping Document D416096

Page 20 of 32

Attachment 4. Clopyralid International Residue Limits Table

Clopyralid (117401/117403; 10/29/2013)

Table A.4.1. Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico2 Codex

40 CFR 180.431

(a) General. Tolerances are established for 

residues of the herbicide clopyralid, including 

its metabolites and degradates, in or on the 

commodities in the table below from its 

application in the acid form or in the form of 

its salts. Compliance with the tolerance levels 

specified below is to be determined by 

measuring only clopyralid, (3,6-dichloro-2-

pyridinecarboxylic acid)

3,6-dichloro-2-pyridinecarboxylic 

acid

None None

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

US Canada Mexico2 Codex

Apple 0.05

Asparagus 1.0

Barley, bran 12 

Barley, grain 3.0 3

7 barley milling fractions, excluding 

flour

Barley, hay 9.0 

Barley, pearled barley 12 

Barley, straw 9.0

Beet, garden, tops 3.0 3

Beet, garden, roots 4.0 4

Beet, sugar, molasses 10 10

Beet, sugar, roots 2.0 2

Beet, sugar, tops 3.0 

Brassica, head and stem, subgroup 

5A

2.0 2 broccoli, brussels sprouts, 

cabbage, cauliflower, Chinese 

broccoli, Chinese mustard 

cabbages, kohlrabi, napa Chinese 

cabbages

Brassica, leafy greens, subgroup 5B 5.0 5 mustard greens

Bushberry subgroup 13-07B 0.50 0.1 blueberries

Canola, meal 6.0 

Canola, seed 3.0 3 rapeseeds (canola)

Cattle, fat 1.0 0.05

Cattle, liver 3.0 0.05 meat byproducts of cattle

Cattle, meat 1.0 0.05

Cattle, meat byproducts, except liver 36.0 0.36 kidney of cattle

Corn, field, forage 3.0

Corn, field, grain 1.0 1

Corn, field, milled byproducts 1.5

Corn, field, stover 10.0

Corn, pop, grain 1.0 1

Corn, pop, stover 10.0 

Corn, sweet, forage 7.0 
Clopyralid Registration Review Human Health Scoping Document D416096

Page 21 of 32

Table A.4.1. Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico2 Codex

Corn, sweet, kernel plus cob with 

husks removed

1.0 1

Corn, sweet, stover 10.0 

Cranberry 4.0 4

Egg 0.1 0.05

Flax, meal 6.0 

Fruit, stone, group 12 0.5 0.5 American plums, Apricots, 

beach plums, black cherries, 

Canada plums, capulins, cherry 

plums, chicksaw plums, 

chokecherries, damson plums, fresh 

prune plums, Japanese apricots, 

Japanese plums, klamath plums, 

nanking cherries, nectarines, 

peaches, plumcots, plums, sloes, 

sweet cherries, tart cherries

Goat, fat 1.0 0.05

Goat, liver 3.0 0.05 meat byproducts of goats

Goat, meat 1.0 0.05

Goat, meat byproducts, except liver 36.0 0.36 kidney of goats

Grass, forage 500.0 

Grass, hay 500.0 

Hog, fat 0.2 0.05

Hog, meat 0.2 0.05

Hog, meat byproducts 0.2 0.05 

Hop, dried cones 5.0 5

Horse, fat 1.0 0.05

Horse, liver 3.0 0.05 meat byproducts of horses

Horse, meat 1.0 0.05

Horse, meat byproducts, except liver 36.0 0.36 kidney of horses

Milk 0.2 0.01

Oat, forage 9.0

Oat, grain 3.0 3

7 oat milling fractions, excluding 

flour

Oat, groats/rolled oats 12 

Oat, straw 9.0

Peppermint, tops 3.0 3

Plum, prune, dried 1.5 1.5 dried prune plums

Poultry, fat 0.2 0.05

Poultry, meat 0.2 0.05

Poultry, meat byproducts 0.2 0.2 kidney of poultry

Rapeseed, forage 3.0 

Rapeseed, meal 6.0

Rapeseed, subgroup 20A, except gold 

of pleasure

3.0 3 flaxseeds, mustard seeds (oil seed 

type) 

Sheep, fat 1.0 0.05

Sheep, liver 3.0 0.05 meat byproducts of sheep

Sheep, meat 1.0 0.05

Sheep, meat byproducts, except liver 36.0 0.36 kidney of sheep

Spearmint, tops 3.0 3
Clopyralid Registration Review Human Health Scoping Document D416096

Page 22 of 32

Table A.4.1. Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico2 Codex

Spinach 5.0 5

Strawberry 4.0 1

Swiss chard 3.0

Teff, forage 9.0

Teff, grain 3.0

Teff, hay 9.0

Teff, straw 9.0

Turnip, greens 4.0 4 turnip tops

Turnip, roots 1.0 1

Wheat, bran 12

Wheat, forage 9.0

Wheat, germ 12 

Wheat, grain 3.0 3

7 wheat milling fractions, excluding 

flour

Wheat, middling 12 

Wheat, shorts 12 

Wheat, straw 9.0

Completed by: M. Negussie; 10/31/13

1 Mexico adopts U.S. tolerances and/or Codex MRLs for its export purposes.
Clopyralid Registration Review Human Health Scoping Document D416096

Page 23 of 32

Attachment 5 – Summary of End-Use Products Containing Clopyralid

Summary Report for 117401 - Monoethanolamine

Registration # Name Status Restricted 

Use Product Company # Company Name

Percent 

Active 

Ingredient

Active Ingredient

228-332 MILLENNIUM ULTRA 2

Conditionally 

Registered (01-

Apr-1998)

N 228 NUFARM 

AMERICAS, INC. 2.54 Clopyralid, 

monoethanolamine salt

228-333

RIVERDALE MCDA 

L.A.C. SELECTIVE 

HERBICIDE

Conditionally 

Registered (25-

Feb-1998)

N 228 NUFARM 

AMERICAS, INC. 2.58 Clopyralid, 

monoethanolamine salt

228-344

RIVERDALE 

MILLENNIUM ULTRA 

GRANULAR WEED 

KILLER

Conditionally 

Registered (09-

Jun-2004)

N 228 NUFARM 

AMERICAS, INC. 0.187 Clopyralid, 

monoethanolamine salt

228-372 ECLIPSE SELECTIVE 

HERBICIDE

Conditionally 

Registered (28-

Feb-2000)

N 228 NUFARM 

AMERICAS, INC. 2.53 Clopyralid, 

monoethanolamine salt

228-491 CLEAN SLATE

Conditionally 

Registered (08-

Aug-2006)

N 228 NUFARM 

AMERICAS, INC. 40.9 Clopyralid, 

monoethanolamine salt

228-564 BRAZEN HERBICIDE Registered (08-

Apr-2008) N 228 NUFARM AMERICAS, INC. 12.1 Clopyralid, monoethanolamine salt

34704-885 CLOPYRALID

Conditionally 

Registered (24-

Aug-2005)

N 34704 LOVELAND 

PRODUCTS, INC. 40.9 Clopyralid, 

monoethanolamine salt

34704-895 COLT

Conditionally 

Registered (03-

Nov-2005)

N 34704 LOVELAND 

PRODUCTS, INC. 11.3 Clopyralid, 

monoethanolamine salt

42750-89 CLOPYRALID MEA AG

Conditionally 

Registered (01-

Jun-2005)

N 42750 ALBAUGH INC 40.9 Clopyralid, 

monoethanolamine salt

42750-92 CLOPYRALID MEA+2,4-

D

Conditionally 

Registered (01-

Jun-2005)

N 42750 ALBAUGH INC 5.1 Clopyralid, 

monoethanolamine salt
Clopyralid Registration Review Human Health Scoping Document D416096

Page 24 of 32

Registration # Name Status Restricted 

Use Product Company # Company Name

Percent 

Active 

Ingredient

Active Ingredient

42750-94 CLOPYRALID MEA IVM

Conditionally 

Registered (15-

Jun-2005)

N 42750 ALBAUGH INC 40.9 Clopyralid, 

monoethanolamine salt

42750-95 CLOPYRALID MEA T&O

Conditionally 

Registered (15-

Jun-2005)

N 42750 ALBAUGH INC 40.9 Clopyralid, 

monoethanolamine salt

42750-201 FLUROXYPYR + 

CLOPYRALID

Conditionally 

Registered (23-

Sep-2009)

N 42750 ALBAUGH INC 11.3 Clopyralid, 

monoethanolamine salt

53883-254 CLOPYRALID 3 LB Registered (03-

Feb-2009) N 53883 CONTROL SOLUTIONS, INC. 40.9 Clopyralid, monoethanolamine salt

62719-48 CURTAIL Registered (04-

Dec-1989) N 62719

DOW 

AGROSCIENCES 

LLC

5.1 Clopyralid, 

monoethanolamine salt

62719-73 STINGER Registered (04-

Dec-1989) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

62719-83 RECLAIM Registered (04-

Dec-1989) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

62719-84

LONTREL 35A 

HERBICIDAL 

CONCENTRATE

Registered (04-

Dec-1989) N 62719

DOW 

AGROSCIENCES 

LLC

46.1 Clopyralid, 

monoethanolamine salt

62719-259 TRANSLINE

Conditionally 

Registered (30-

Mar-1994)

N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

62719-512 WIDEMATCH 

HERBICIDE

Conditionally 

Reregistered (30-

Apr-2004)

N 62719

DOW 

AGROSCIENCES 

LLC

11.3 Clopyralid, 

monoethanolamine salt

62719-635 GF-2506 Registered (28-Jul2011) N 62719

DOW 

AGROSCIENCES 

LLC

12 Clopyralid, 

monoethanolamine salt

62719-645 GF-2791 Registered (15-

Feb-2012) N 62719 DOW AGROSCIENCES 30.82 Clopyralid, monoethanolamine salt
Clopyralid Registration Review Human Health Scoping Document D416096

Page 25 of 32

Registration # Name Status Restricted 

Use Product Company # Company Name

Percent 

Active 

Ingredient

Active Ingredient

LLC

70506-94 AGVALUE CLOPYRALID 

AG HERBICIDE

Conditionally 

Registered (06-

May-2003)

N 70506 UNITED 

PHOSPHORUS, INC 40.9 Clopyralid, 

monoethanolamine salt

71368-66 GARRISON HERBICIDE

Conditionally 

Registered (11-

Aug-2006)

N 71368 NUFARM, INC. 40.9 Clopyralid, 

monoethanolamine salt

71368-86 TRUSLATE SELECTIVE 

HERBICIDE

Conditionally 

Registered (19-

Dec-2008)

N 71368 NUFARM, INC. 11.3 Clopyralid, 

monoethanolamine salt

81927-14 ALLIGARE CLOPYRALID 

3

Conditionally 

Registered (25-

May-2007)

N 81927 ALLIGARE, LLC 40.9 Clopyralid, 

monoethanolamine salt

81927-28 ALLIGARE CODY 

HERBICIDE

Registered (24-

Jun-2008) N 81927 ALLIGARE, LLC 5.1 Clopyralid, monoethanolamine salt

81927-28 ALLIGARE CODY 

HERBICIDE

Registered (24-

Jun-2008) N 81927 ALLIGARE, LLC 39 2,4-D, triisopropanolamine salt

CA990010 TRANSLINE Registered (07-

Oct-1999) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

CA990027 STINGER Registered (20-

Feb-2000) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

GA110003 STINGER Registered (26-

May-2011) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

ID040011 STINGER Registered (15-

Oct-2004) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

MI100004 STINGER Registered (27-

Oct-2010) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

MI110001 STINGER Registered (24-

May-2011) N 62719 DOW AGROSCIENCES 40.9 Clopyralid, monoethanolamine salt
Clopyralid Registration Review Human Health Scoping Document D416096

Page 26 of 32

Registration # Name Status Restricted 

Use Product Company # Company Name

Percent 

Active 

Ingredient

Active Ingredient

LLC

NY040004 STINGER Reregistered (05-

Aug-2004) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

OR030009 STINGER Registered (29-Jul2003) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

OR090018 STINGER Registered (10-

Mar-2011) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

OR100011 STINGER Registered (27-

Oct-2010) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

OR120010 STINGER Registered (06-

Sep-2012) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

OR970024 STINGER Registered (12-

Jan-1998) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

WA030006 STINGER Registered (30-

Jan-2009) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

WA100005 STINGER Registered (25-

Oct-2011) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

WA970033 STINGER Registered (26-

Oct-1997) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

WI080002 STINGER Registered (18-

Jun-2008) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt

WI100003 STINGER Registered (03-

Sep-2010) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt
Clopyralid Registration Review Human Health Scoping Document D416096

Page 27 of 32

Registration # Name Status Restricted 

Use Product Company # Company Name

Percent 

Active 

Ingredient

Active Ingredient

WI130008 STINGER Registered (03-Jul2013) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid, 

monoethanolamine salt
Clopyralid Registration Review Human Health Scoping Document D416096

Page 28 of 32

Summary Report for 117403 - Clopyralid

Registration # Name Status Restricted 

Use Product

Company 

# Company Name

Percent 

Active 

Ingredient

Active Ingredient

228-323 RIVERDALE TRUPOWER 

SELECTIVE HERBICIDE

Conditionally 

Registered (26-

Nov-1997)

N 228 NUFARM 

AMERICAS, INC. 5.18 Clopyralid

228-343 MILLENNIUM ULTRA 

WEED AND FEED

Conditionally 

Registered (03-

Oct-1998)

N 228 NUFARM 

AMERICAS, INC. 0.071 Clopyralid

228-371

RIVERDALE MTCA 

PREMIUM SELECTIVE 

HERBICIDE

Conditionally 

Registered (01-

Feb-2000)

N 228 NUFARM 

AMERICAS, INC. 1.3 Clopyralid

228-568 BRAZEN SF HERBICIDE Registered (08-

Apr-2008) N 228 NUFARM AMERICAS, INC. 12.1 Clopyralid

352-593 ACCENT GOLD 

HERBICIDE

Conditionally 

Registered (19-

Nov-1997)

N 352

E. I. DU PONT DE 

NEMOURS AND 

COMPANY 

(S300/419)

51.7 Clopyralid

352-612 DUPONT ACCENT GOLD 

WDG HERBICIDE

Conditionally 

Registered (08-

Aug-2001)

N 352

E. I. DU PONT DE 

NEMOURS AND 

COMPANY 

(S300/419)

51.4 Clopyralid

1381-246 WELD HERBICIDE Registered (18-

Mar-2011) N 1381 WINFIELD SOLUTIONS, LLC 5.6 Clopyralid

5905-590 HM-1144 HERBICIDE Registered (21-

Feb-2013) N 5905 HELENA CHEMICAL CO 6 Clopyralid

34704-1017 HAT TRICK THREE WAY 

HERBICIDE

Conditionally 

Registered (16-

Apr-2009)

N 34704 LOVELAND 

PRODUCTS, INC. 6 Clopyralid

34704-1019 COLT CF HERBICIDE

Conditionally 

Registered (13-

Aug-2009)

N 34704 LOVELAND 

PRODUCTS, INC. 8.6 Clopyralid

35935-57 CLOPYRALID 

TECHNICAL HERBICIDE

Conditionally 

Registered (24-

Mar-2009)

N 35935 NUFARM LIMITED 97 Clopyralid

35935-84 MILLENNIUM ULTRA Registered (27- N 35935 NUFARM LIMITED 5.58 Clopyralid
Clopyralid Registration Review Human Health Scoping Document D416096

Page 29 of 32

Registration # Name Status Restricted 

Use Product

Company 

# Company Name

Percent 

Active 

Ingredient

Active Ingredient

MC Jun-2011)

42750-86 CLOPYRALID 

TECHNICAL

Conditionally 

Registered (17-

May-2005)

N 42750 ALBAUGH INC 98 Clopyralid

42750-91 CLOPYRALID ACID + 

MCPA ESTER

Conditionally 

Registered (01-

Jun-2005)

N 42750 ALBAUGH INC 5 Clopyralid

42750-184 CLOPYRALID 

TECHNICAL HERBICIDE

Conditionally 

Registered (19-

May-2008)

N 42750 ALBAUGH INC 97 Clopyralid

58501-1 CONFRONT WEED 

STICK

Canceled (29-Jul2002) N 58501 TERAGRO INC. 0.57 Clopyralid

62719-80 LONTREL T TECHNICAL

Conditionally 

Registered (04-

Dec-1989)

N 62719

DOW 

AGROSCIENCES 

LLC

95 Clopyralid

62719-81 LONTREL F TECHNICAL

Conditionally 

Registered (04-

Dec-1989)

N 62719

DOW 

AGROSCIENCES 

LLC

80.8 Clopyralid

62719-86 CURTAIL M

Conditionally 

Registered (04-

Dec-1989)

N 62719

DOW 

AGROSCIENCES 

LLC

5 Clopyralid

62719-217 XRM-5202

Conditionally 

Registered (12-

Dec-1996)

N 62719

DOW 

AGROSCIENCES 

LLC

1.3 Clopyralid

62719-232 CONFRONT* F

Conditionally 

Registered (16-

Apr-1992)

N 62719

DOW 

AGROSCIENCES 

LLC

12.1 Clopyralid

62719-253 HORNET

Conditionally 

Registered (25-

May-1994)

N 62719

DOW 

AGROSCIENCES 

LLC

62.5 Clopyralid

62719-262 TURF FERTILIZER 

CONTAINS CONFRONT

Conditionally 

Reregistered (18-

Sep-2000)

N 62719

DOW 

AGROSCIENCES 

LLC

0.18 Clopyralid

62719-278 NAF-280 Conditionally N 62719 DOW 56.3 Clopyralid
Clopyralid Registration Review Human Health Scoping Document D416096

Page 30 of 32

Registration # Name Status Restricted 

Use Product

Company 

# Company Name

Percent 

Active 

Ingredient

Active Ingredient

Registered (26-

Mar-1996)

AGROSCIENCES 

LLC

62719-279 NAF-281

Conditionally 

Registered (26-

Mar-1996)

N 62719

DOW 

AGROSCIENCES 

LLC

56.3 Clopyralid

62719-300 HORNET MUP

Conditionally 

Registered (11-

Feb-1998)

N 62719

DOW 

AGROSCIENCES 

LLC

62.5 Clopyralid

62719-305 LONTREL TURF AND 

ORNAMENTAL

Conditionally 

Registered (14-

Oct-1998)

N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid

62719-337 REDEEM R & P

Conditionally 

Registered (16-

Mar-2000)

N 62719

DOW 

AGROSCIENCES 

LLC

12.1 Clopyralid

62719-570 SURESTART HERBICIDE Registered (01-

Mar-2007) N 62719

DOW 

AGROSCIENCES 

LLC

4.27 Clopyralid

70506-93 AGVALUE CLOPYRALID 

TECHNICAL

Conditionally 

Registered (01-

May-2003)

N 70506 UNITED 

PHOSPHORUS, INC 96 Clopyralid

71368-88 TRUSLATE PRO 

HERBICIDE

Conditionally 

Registered (01-

Apr-2009)

N 71368 NUFARM, INC. 5.6 Clopyralid

75147-L CLOPYR-M Under Review (03-

Sep-2002) N 75147 AGVALUECLOPYR, LLC 5 Clopyralid

89167-GU AX ACETOCHLOR + 2 

HERBICIDE

Under Review (26-

Aug-2013) N 89167 AXION AGPRODUCTS, LLC 4.27 Clopyralid

ID130010 COLT CF HERBICIDE Registered (12-

Aug-2013) N 34704 LOVELAND PRODUCTS, INC. 8.6 Clopyralid

WI030003 STINGER Registered (29-

Apr-2003) N 62719

DOW 

AGROSCIENCES 

LLC

40.9 Clopyralid

62719-EUP-26 Issued (19-May1994) N 62719 DOW 

AGROSCIENCES 23.1 Clopyralid
Clopyralid Registration Review Human Health Scoping Document D416096

Page 31 of 32

Registration # Name Status Restricted 

Use Product

Company 

# Company Name

Percent 

Active 

Ingredient

Active Ingredient

LLC

62719-EUP-27 Issued (02-Jun1994) N 62719

DOW 

AGROSCIENCES 

LLC

25 Clopyralid
Clopyralid Registration Review Human Health Scoping Document D416096

Page 32 of 32

Summary Report for 117404 – Triethanolamine Salt

Registration # Name Status Restricted 

Use Product Company # Company Name

Percent 

Active 

Ingredient

Active 

Ingredient

961-390

LEBANON LAWN 

FERTILIZER CONTAINS 

CONFRONT AND TEAM

Conditionally 

Registered (12-

Jan-2001)

N 961 LEBANON SEABOARD 

CORPORATION 0.18 Clopyralid, 

triethanolamine

961-391

LEBANON TURF 

FERTILIZER WITH 

CONFRONT AND TEAM

Conditionally 

Registered (12-

Jan-2001)

N 961 LEBANON SEABOARD 

CORPORATION 0.18 Clopyralid, 

triethanolamine

42750-125 TRICLOPYR TEA + 

CLOPYRALID TEA R&P

Registered (06-

Apr-2006) N 42750 ALBAUGH INC 12.1 Clopyralid, triethanolamine

62719-92 CONFRONT

Conditionally 

Registered (04-

Dec-1989)

N 62719 DOW AGROSCIENCES 

LLC 12.1 Clopyralid, 

triethanolamine

66222-222 QUALI-PRO 2-D 

HERBICIDE

Registered (22-

Nov-2010) N 66222

MAKHTESHIM AGAN 

OF NORTH AMERICA, 

INC.

12.1 Clopyralid, 

triethanolamine

81927-30 ALLIGARE PRESCOTT 

HERBICIDE

Registered (29-

Apr-2008) N 81927 ALLIGARE, LLC 12.1 Clopyralid, triethanolamine

Summary Report for 117423 – Potassium Salt

Registration # Name Status Restricted 

Use Product

Company 

# Company Name

Percent 

Active 

Ingredient

Active 

Ingredient

62719-315 HORNET WDG

Conditionally 

Registered (27-Jul1999)N 62719 DOW AGROSCIENCES 

LLC 60 Clopyralid 

potassium