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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION

MEMORANDUM

Date: April 29, 2014

SUBJECT: Triclopyr, salts and esters: Tier I Review of Human Incidents

PC Code: 116001, 116002, 116004 DP Barcode: D419814

Decision No.: 487442 Registration No.: NA

Petition No.: NA Regulatory Action: NA

Risk Assessment Type: NA Case No.: NA

TXR No.: NA CAS No.: 55335-06-3

MRID No.: NA 40 CFR: NA

 Ver.Apr.08

 

FROM: Elizabeth Evans, Environmental Protection Specialist

Toxicology and Epidemiology Branch

Health Effects Division (7509P)

and

Shanna Recore, Industrial Hygienist

Toxicology and Epidemiology Branch

Health Effect Division (7509P)

THROUGH: David Miller, Acting Branch Chief

Toxicology and Epidemiology Branch

Health Effects Division (7509P)

TO: Jennifer Tyler, Risk Assessor

Risk Assessment Branch I

Health Effects Division (7509P)

and

Monica Wait, Chemical Review Manager

Risk Management & Implementation Branch 3

Pesticide Re-evaluation Division (7508P)

Summary and Conclusions

There is a moderately high absolute number of incidents reported involving triclopyr in IDS. 

Although vast majority of these incidents were of low severity, some high severity outcomes are 

reported in the IDS database. Based on the IDS reports, incidents usually involved homeowners 

who were mixing/loading and/or applying and the symptoms most often reported were dermal 

and neurological. 
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While incident information can be an important source of feedback to the Agency, 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. Nevertheless, based on the 

absolute number of incidents and the few high severity outcomes that are reported, these incident 

data may warrant further analysis in the preliminary risk assessment phase of Registration 

Review. Obtaining additional information on current usage data for triclopyr would improve 

future assessments.

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. 

II. BACKGROUND

Triclopyr TEA and BEE products are used as selective herbicides to control broad leaf weeds 

and brush on a variety of sites-- rights-of-way, pasture and rangelands, forests, rice, and turf, 

including home lawns. Triclopyr products are formulated as soluble concentrates, emulsifiable 

concentrates, liquids (pressurized and ready-to-use), granulars, wettable powders and pellets.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 triclopyr, salts and esters (pc code: 

116001, 116002, 116004). The purpose of the database search is to identify potential patterns in 

the frequency and severity of the health effects attributed to triclopyr, salts and esters exposure. 

Triclopyr, salts and esters is not included in the AHS, and therefore this study does not provide 

information for this report.

III. RESULTS/DISCUSSION

 

1 http://www.epa.gov/oppsrrd1/REDs/factsheets/2710fact.pdf
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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 

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

the 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, 2009 to January 15, 2014, there were 73 incidents reported 

for single chemical only in the database. 2 Five incidents were classified as major severity and 

68 incidents were classified as moderate severity. The incident narratives for incidents classified 

as major severity are included in Appendix 1. There were 108 additional incidents reported 

involving more than one chemical. 

In Aggregate IDS, from January 1, 2009 to January 15, 2014, there were 721 reported incidents 

involving triclopyr. Twelve eight incidents were classified as unknown or no effects and 709

incidents were classified as minor severity. 

In Main IDS, the reported incidents usually involved homeowners who were mixing/loading 

and/or applying (n=53). Based on the IDS reports, symptoms most often reported were dermal 

(n=34), neurological (n=21). Dermal symptoms reported include hives, swelling, rash, burning 

sensation, blotches, redness, and itchiness. Neurological symptoms reported include muscle 

cramps, headaches, paresthesia, ataxia, disorientation, and dizziness. It should be noted that in 

 

2 There were 2 foreign incidents were not reviewed in detail because of the potential differences in the exposure 

patterns, use practices, and product formulation. These incidents occurred in Canada and China. 
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some of the incidents where people reported dermal symptoms, they were treating poison ivy. 

They may have been experiencing a reaction to poison ivy and not the implicated product. 

The most often implicated product in both Main and Aggregate IDS is Reg. No. 228-424-239

(Weed-B-Gon Max). It was implicated in 29% of the triclopyr incidents reported to IDS. This 

may be potentially attributable to high use of this product by consumers. Obtaining additional 

information on current usage data for triclopyr would improve future assessments. Weed-B-Gon 

Max is used by homeowners to control weeds on lawns. It is a concentrate that can be applied 

with either a tank sprayer or hose end sprayer. In addition to containing 1.56 % triclopyr, this 

product also contains MCPA (13.72%) and dicamba (1.35%). 

b. SENSOR-Pesticides

The SENSOR-Pesticides database covers 11 states from 1998-2010, 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 1998-2010 identifies a total of 26 cases involving triclopyr, salts 

and esters (pc codes 116001, 116002, 116003). Twelve cases, stemming from five events, 

involve a single ai (116001). All 12 were low in severity. One multiple exposure event that led

to eight case reports occurred in Michigan in 2010. The event description states, “Campers 

canoed out to an island, went swimming. After about 30 minutes, they saw sign that said the lake 

was treated that day.” These 8 campers reported itchy rashes and the camp nurse contacted the 

local Poison Control Center.

Table 1. SENSOR-Pesticides 1998-2010: Reported 

Health Effects for Triclopyr Cases 

N=12

Health Effect # of Times Reported

Dermal 10

Ocular 1

Respiratory 0

Gastrointestinal 2

Nervous System 1

Cardiovascular 1

* Cases may report multiple health effects
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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 formulation/scoping 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. Triclopyr, salts and esters is not included in the 

AHS, and therefore this study does not provide information for this report.

IV. CONCLUSION

There is a moderately high absolute number of incidents reported involving triclopyr in IDS.

Although vast majority of these incidents were of low severity, some high severity outcomes are 

reported in the IDS database. Based on the IDS reports, incidents usually involved homeowners 

who were mixing/loading and/or applying and the symptoms most often reported were dermal 

and neurological. 

While incident information can be an important source of feedback to the Agency, 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. Nevertheless, based on the 

absolute number of incidents and the few high severity outcomes that are reported, these incident 

data may warrant further analysis in the preliminary risk assessment phase of Registration 

Review. Obtaining additional information on current usage data for triclopyr would improve 

future assessments.
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Appendix 1. Main IDS Major Severity Incidents Descriptions for Triclopyr, salts and esters. 

Human Incident Chemical: Triclopyr, salts and esters PC Codes: 116001, 116002, 116004

Incident 

Package 

Report

Incident 

Date Location

Reg 

Number Product Name Incident Description

022005 -

00004 5/3/2010

PITTSBURGH, 

PA

000239-

02587

ORTHO MAX 

POISON IVY & 

TOUGH BRUSH 

KILLER READY 

TO USE

A 47 year old male was using a wood chipper to cut down hedges 

and breathed in the dust. Within hours he had a severe headache 

and the next day went to the ER. The product had been use 1 

year prior in the area he was working in 1 year prior to this event.

022933 -

00019 4/15/2010 NY

000239-

02491

ORTHO MAX 

POISON IVY & 

TOUGH BRUSH 

KILLER 

CONCENTRATE

An adult female was using product and removing brush and a 

thorn went through her glove. Removed glove and where the 

thorn went in the skin swelled up right away. Two weeks later, she 

went to dermatologist who gave medication that did not do 

anything. Went back two more times and finger was injected with

cortisone. Eventually two nodules developed within the skin on 

her pinky finger where the thorn went through the skin. The 

caller's general practitioner recommended that she see a hand 

and hone specialist who is set on the diagnosis being arthritis. 

Radiographs were negative and today she is going in for an MRI.

022933 -

00033 4/26/2011 OH

BRUSH-B-GON 

(NONSPECIFIC)

A 60 year old male applied product had some accidental contact 

with fingertips and he was not wearing a respirator when spraying.

The next day the caller experienced muscle weakness and 

describes difficulty in trying to stand and mental confusion. He 

went to the ER and was diagnosed with having had a mild stroke.

023382 -

00021 9/14/2010 TN

000239-

02491

ORTHO MAX 

POISON IVY & 

TOUGH BRUSH 

KILLER 

CONCENTRATE

About a year prior to reporting the incident, an 80 year old female 

applied the product and got some on herself. She washed the 

product off about 40 minutes later. She began to experience 

confusion and vertigo. As time progressed, she experience 

generalized throbbing through her entire body and all over body 

pain. She has seen numerous doctors and can only get relief with 

medication.

024332 -

00003 5/30/2012

JACKSONVILLE, 

FL

062719-

00040

ELEMENT 4 

SPECIALTY 

HERBICIDE

A 59 year old male farmer used the product, and about 24 hrs 

later he began to feel weak, and had paresthesias to face, and 

legs. He also complained of lumbar pain. He appears to have 

descending paralysis. The only information available is that he 

had used the product previously, however, there is no history
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Human Incident Chemical: Triclopyr, salts and esters PC Codes: 116001, 116002, 116004

Incident 

Package 

Report

Incident 

Date Location

Reg 

Number Product Name Incident Description

indicating any point of defined exposure. No obvious pulmonary 

symptoms observed. Only significant medical hx is for HTN and 

acid reflux. The patient is deteriorating neurologically. Medical 

staff are trying to determine if exposure to this product could 

cause this type of illness.