UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Date: November 20, 2013 

SUBJECT: Clopyralid: Tier I Review of Human Incidents 

PC Code: 11 7401, 117403, 117404, 117423 

Decision No.: 484816 

Petition No.: NA 

DP Barcode: D416106 

Registration No.: NA 

Regulatory Action: NA 

Risk Assessment Type: NA Case No.: NA 

TXRNo.: NA 

MRIDNo.: NA 

CAS No.: 57754-85-5, 1702-1 7-6, 58509-83-4 

40CFR: NA 

FROM: 

Ver.Apr.08 

Toxicology 

Elizabeth Evans, 

and Epidemiology 

Environmental 

Branch 

Protection Specialist 

c ~~~ 

, 

~V~ 

_, ~ Health Effects Division (7509P) l a·-. and 

Shanna Recore, Industrial Hygienist IJ,., A 6

" , 

Toxicology and Epidemiology Branch ~~/.A._ Health Effect Division (7509P) 1/A /7/ l /. ]{J.fiJ/. lot? 

THROUGH: David Miller, Acting Branch ChieaJ / ~ 

Toxicology and Epidemiology Branch 

Health Effects Division (7509P) 

TO: Michael Doherty, Risk Assessor 

Risk Assessment Branch II 

Health Effects Division (7509P) 

and 

Steven Snyderman, Chemical Review Manager 

Risk Management & Implementation Branch 3 

Pesticide Re-evaluation Division (7508P) 

Summary and Conclusions 

Based on the low frequency and generally low severity of incident cases reported for clopyralid 

in both IDS and SENSOR-Pesticides, 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. 

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Detailed Review 

I. ACTION REQUESTED 

This review is intended to fulfill our requirement to docket summaries of incident data that were 

reported to the Agency, as well as to ensure human incident data and the Agricultural Health 

Study (AHS) are part of the problem formulation phase of registration review. Reports of 

adverse health effects allegedly due to a specific pesticide exposure (i.e., an "incident") are 

largely self-reported and therefore, generally speaking, neither exposure to a pesticide or 

reported symptom (or the connection between the two) is validated or otherwise confirmed. 

Typically, causation cannot be determined based on incident data. However, incident 

information can be an important source of feedback to the Agency: incidents of severe outcome, 

or a suggested pattern or trend among less severe incidents, can signal the Agency to further 

investigate a particular chemical or product. Observational epidemiology studies relate the risk 

of disease, e.g. , cancer, and exposure to an agent such as a pesticide product in the general 

population or specific sub-groups like pesticide applicators. 

D. BACKGROUND 

Clopyralid is a pyridine herbicide registered for use on a variety of food and feed crops in the 

U.S. for the postemergence control ofbroadleafweeds, particularly thistles and clover. The enduse product that IR-4 proposed for use on these commodities is Stinger® Herbicide (EPA Reg. 

No. 62719-73), which is a 3 lb acid equivalent (ae)/gal emulsifiable concentrate (EC) 

formulation of the monoethanolamine salt of clopyralid. 1 

For this evaluation, both the OPP Incident Data System (IDS) and the Centers for Disease 

Control and Prevention/National Institute for Occupational Safety and Health (CDC/NIOSH) 

Sentinel Event Notification System for Occupational Risk-Pesticides (SENSOR) databases were 

consulted for pesticide incident data on the active ingredient clopyralid (pc codes: 117401, 

117403, 117404, and 117423). The purpose of the database search is to identify potential 

patterns in the frequency and severity of the health effects attributed to clopyralid exposure. 

Clopyralid is included in the AHS, but is only in phase III and the data is not currently available. 

Therefore this study does not provide information for this report. 

III. RESULTS/DISCUSSION 

a. IDS (Incident Data System) 

OPP's IDS includes reports of alleged human health incidents from various sources, including 

mandatory Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Section 6(a)(2) reports 

from registrants, other federal and state health and environmental agencies, and individual 

consumers. Since 1992, OPP has compiled these reports in IDS. IDS contains reports from 

across the U.S. and most incidents have all relevant product information recorded. Reports 

1 Clopyralid Human Health Risk Assessment, OP Nos. 0391397,040 1055 

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submitted to the IDS represent anecdotal reports or allegations only, unless otherwise stated in 

the report. It should be noted there is one incidents reported as a lawsuit to IDS that is not 

considered in this report. 

IDS records incidents in one of two modules: Main IDS and Aggregate IDS: 

o Main IDS contains incidents resulting in higher severity outcomes and provides 

more detail with regard to case specifics. This system stores incident data for 

death, major and moderate incidents, and it includes information about the 

location, date and nature of the incident. Main IDS incidents involving only one 

active ingredient (as opposed to pesticide products with multiple active 

ingredients) are considered to provide more certain information about the 

potential effects of exposure from the pesticide. 

o Aggregate IDS contains incidents resulting in less severe human incidents (minor, 

unknown, or no effects outcomes). These are reported by registrants only as 

counts in what are aggregate summaries. 

For the Main IDS, from January 1, 2008 to September 11, 2013, there were 0 incidents reported 

for single chemical only in the database. There were 5 incidents reported involving more than 

one chemical? These incidents were classified as moderate severity. Overall, there are few 

incidents involving clopyralid reported to IDS. 

In Aggregate IDS, from January 1, 2008 to September 11,2013, there were 39 reported incidents 

involving clopyralid. 

b. SENSOR-Pesticides 

The SENSOR-Pesticides database covers 11 states from 1998-2009, although reporting varies 

from state to state. Cases of pesticide-related illnesses are ascertained from a variety of sources, 

including: reports from local Poison Control Centers, state Department of Labor workers' 

compensation claims when reported by physicians, reports from State Departments of 

Agriculture, and physician reports to state Departments of Health. Although both occupational 

and non-occupational incidents are included in the database, SENSOR-Pesticides focuses on 

occupational pesticide incidents, and is of particular value in providing that information. The 

state coordinator at each of the 11 respective state Departments of Health conducts case followup activities such as obtaining medical records to verify symptoms and severity. Using 

standardized protocol and case definitions derived from poison center reporting, the state 

SENSOR-Pesticide coordinator enters the incident information into the state-based system which 

is sent to NIOSH annually to be aggregated. 

A query of SENSOR-Pesticides identifies a total of 45 cases involving clopyralid. Three cases 

involved a single active ingredient and will be analyzed in this memo. All three cases were low 

2 There was also one incident that occurred in Argentina an d one incident that occurred in China. Foreign incidents 

are not reviewed in detail because of the potential differences in the exposure patterns, use practices, and product 

formulation. 

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in severity. All three occurred at the case's place of work. All three cases reported respiratory 

symptoms. 

One case occurred in Louisiana in 2003 and is described as follows, "Aerial drift from helicopter 

while complainant was working near a forest." Another case occurred in Washington in 2002 

and is described as, "A 36 y/o female asparagus cutter developed systemic and topical symptoms 

after breathing pesticide vapors from an application approximately 75 feet away." The third case 

report did not include a case description. 

Table 1. SENSOR-Pesticides 1998-2009: Reported 

Health Effects for Clopyralid Cases 

Health Effect Frequency 

Dermal 1 

Ocular 1 

Respiratory 3 

Gastrointestinal 0 

Renal 0 

Nervous System 2 

Cardiovascular 0 

Miscellaneous 2 

* Cases may report multiple health effects 

c. Agricultural Health Study (AHS) 

The AHS is a high quality, prospective epidemiology study evaluating the link between pesticide 

use and various health outcomes including cancer. The AHS includes private and commercial 

pesticide applicators and their spouses. If there are AHS findings relevant to a particular 

pesticide going through registration review, the Agency will ensure they are considered in the 

problem formulationlscoping phase of the process and, if appropriate, fully reviewed in the risk 

assessment phase of the process. The AHS includes information on use of 50 different pesticide 

active ingredients commonly used in agriculture. Clopyralid is included in the AHS, but is only 

in phase III and the data is not currently available. Therefore this study does not provide 

information for this report. 

IV. CONCLUSION 

Based on the low frequency and generally low severity of incident cases reported for clopyralid 

in both IDS and SENSOR-Pesticides, there does not appear to be a concern at this time that 

would warrant further investigation. The Agency will continue to monitor the incident 

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

assessment. 

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