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INTRODUCTION

This is the Environmental Protection Agency’s Final Work Plan (FWP) for the registration 

review of triclopyr. This work plan addresses public comments received concerning the 

Preliminary Work Plan (PWP), which was posted in the triclopyr registration review docket 

(EPA-HQ-OPP-2014-0576). Triclopyr acid and its salts and esters (which will be collectively 

referred to as triclopyr throughout the FWP) are systemic herbicides within the pyridine 

carboxylic acid chemical family registered for the control of a number of woody plant and 

weed species. They are registered for use on a number of agricultural crops, including rice,

and for non-agricultural use on range and pasture land, forests, rights of way, turf 

(commercial and homeowner), and numerous aquatic areas for aquatic weed control.

The Agency is implementing the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for 

registration. Changes in science, public policy, and pesticide use practices occur over time. 

The registration review program is intended to make sure that, as the ability to assess risk 

evolves and as policies and practices change, all registered pesticides continue to meet the 

statutory standard. The public phase of registration review begins when the initial docket is 

opened for each case. Information on this program is provided on the Agency’s website.

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The FWP begins with any updates since the PWP was issued. Next is a summary of 

substantive comments received during the public comment period for the PWP concerning 

planned data needs, expected risk assessments, or the estimated timeline identified in the 

PWP, and a summary of the Agency’s responses to those comments. This section is followed 

by registration review planned data needs, risk assessments expected to be conducted, and the 

projected registration review timeline for triclopyr. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

Pollinator Data Needs

On June 23, 2014, EPA, Health Canada’s Pest Management Regulatory Agency, and the 

California Department of Pesticide Regulation issued Guidance for Assessing Pesticide Risks 

to Bees. The guidance describes a tiered risk assessment process, associated data 

requirements, for any pesticides with registered uses resulting in non-target exposures to 

bees. In accordance with this guidance, EPA plans to require the following two honey bee 

toxicity studies for the triclopyr registration review case. These additional data are reflected 

in this FWP in Table 1: Planned Data Needs for Triclopyr Registration Review.

- Guideline (GLN) 850.3040, Full field testing for pollinators

- Non-GLN, Field trial of residues in pollen and nectar 

Aerobic Soil Metabolism Study (835.4100) and Aerobic Aquatic Metabolism Study 

(835.4300) 

An aerobic soil metabolism study (TGAI) and an aerobic aquatic metabolism study (TCP

degradate) were identified as data gaps in the EFED Problem Formulation. These studies 

were inadvertently left out of the Preliminary Work Plan and have been added to the Final 

Work Plan.

 1 http://www.epa.gov/oppsrrd1/registration_review/
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SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60-day public comment period on the triclopyr Preliminary Work Plan, which 

opened on December 18, 2014 and closed on February 18, 2015, the Agency received public 

comments from five sources: the San Francisco Bay Regional Water Quality Control Board, 

the California Stormwater Quality Association (CASQA); Dow AgroSciences; the Physicians 

Committee for Responsible Medicine; and the FIFRA Endangered Species Task Force 

(FESTF). The comments do not address the timeline described in the PWP, but they do 

address the planned ecological and human health risk assessments and data requirements. In 

the PWP, EPA also solicited comments on the specific topics of environmental justice, water 

quality concerns, and trade irritants. Comments were received regarding water quality 

concerns from a California Water Board and CASQA. No comments were provided on 

environmental justice or trade irritants. 

This section does not capture every comment made about the PWP nor all of the Agency’s 

responses. Summarized below are public comments that are of a broader regulatory nature

and the Agency’s response. Public comments and EPA responses in their entirety are located 

in the docket, EPA-HQ-OPP-2014-0576. Summarized public comments and Agency 

responses related to the planned ecological risk assessment or data needs are in the Response 

to Public Comments on the EFED Registration Review Problem Formulation for Triclopyr

dated June 24, 2015.

Comment submitted by FIFRA Endangered Species Task Force (FESTF) in EPA-HQOPP-2014-0576-0015.

1. Comment: The technical registrants for triclopyr, as identified on the fact sheet in the 

PWP, are Nufarm Limited (a subsidiary of Nufarm Americas, Inc.), Albaugh, Inc., 

and Dow AgroSciences, which are FESTF members and are entitled to rely on FESTF 

data.

Response: EPA appreciates FESTF’s comments and will consider this information 

during registration review.

Comment submitted by Dow AgroSciences, LLC in EPA-HQ-OPP-2014-0576-0016.

1. Comment: Dow AgroSciences provided the Triclopyr Registration Review Benefits 

Assessment in Response to Triclopyr Registration Review Docket No. EPA- HQ-OPP2014-0576.

Response: EPA appreciates receiving the triclopyr benefits assessment submitted by 

Dow AgroSciences and will consider this information during registration review.

Comments submitted by California Stormwater Quality Association (CASQA) in EPAHQ-OPP-2014-0576-0017.

1. Comment: CASQA commented that the national total non-agricultural usage data 

reported in the BEAD Memorandum (Table 4) of 100,000 lb acid equivalent (a.e.)

was grossly underestimated.

Response: EPA appreciates CASQA’s comments and the submission of the California 

Department of Pesticide Regulation’s (DPR) Pesticide Use Reports (PUR) from 2012 
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and California DPR sales data. In Table 4 of the BEAD Chemical Profile (BCP) for 

Registration Review: Triclopyr Case, the 100,000 lbs. acid equivalent (a.e.) lbs 

triclopyr applied refers only to the national-level consumer lawn sector data from 

2011. This is not the national total lbs a.e. applied for all non-agricultural uses of 

triclopyr for 2011. Non-agricultural usage data is limited and we do not have a total 

(all sectors combined including lawn care, rights-of-way, etc.) national-level triclopyr 

non-agricultural usage number.

2. Comment: The BEAD Memorandum included conclusions about both rates of nonagricultural use and long-term trends based on 2002-2006 data that included no 

discussion of possible uses in rights-of-way. The California DPR PUR data for 2012 

and prior years could provide a useful dataset for evaluating non-agricultural uses 

and trends.

Response: EPA appreciates CASQA’s comment and will consider this information 

during registration review. The national-level poundage data in Table 1of the BCP for 

Registration Review: Triclopyr Case are from 2002 to 2011. At the time the BCP was 

drafted, national data on lbs of triclopyr applied to rights-of-way were not available. 

3. Comment: CASQA requests additional public participation opportunities.

Response: The EPA currently provides several opportunities for public participation 

at various stages throughout the registration review process, including the opportunity 

to comment at the draft risk assessment and the proposed decision phases. In addition, 

the public may contact the Agency at any time with questions or concerns regarding 

the process.
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PLANNED DATA NEEDS

Table 1 below summarizes planned data needs for triclopyr. Updates have been made to 

include the previously omitted studies and the pollinator data needs mentioned earlier in this 

document. For additional discussion of the planned data needs, see: 

• Registration Review; Preliminary Problem Formulation for Environmental Fate, 

Ecological Risk, Endangered Species, and Human Health Drinking Water Exposure 

Assessments for Triclopyr [Triclopyr Acid (PC Code 116001), Triclopyr 

Triethylamine Salt (PC Code 116002), and Triclopyr Butoxyethyl Ester (PC Code 

116004)], and 

• Triclopyr; Triclopyr, Triethylamine Salt (TEA); and Triclopyr, Butoxyethyl Ester 

(BEE). Human Health Assessment Scoping Document in Support of Registration 

Review.

Table 1: Planned Data Needs for the Triclopyr Registration Review

Guideline 

Number2 Study Title1 Test 

Material

Estimated 

Timeframe

(Months 

from receipt 

of DCI)

Planned Data Needs for Triclopyr

835.2240 Aqueous photolysis TGAI (acid) 12

835.4100 Aerobic soil metabolism TGAI (TEA, 

and BEE) 24

835.4200 Anaerobic soil metabolism

TGAI (acid, 

TEA, and 

BEE)

24

835.4300 Aerobic aquatic metabolism TGAI (BEE) 24

835.4400 Anaerobic aquatic metabolism TGAI (BEE) 24

850.1300 Freshwater invertebrate lifecycle TGAI (BEE) 12

850.1350 Estuarine/marine invertebrate lifecycle TGAI (BEE) 12

850.1730 Fish BCF TGAI (BEE) 12

850.2100 Avian oral toxicity – Passerine TGAI (acid) 12

850.3040 Field testing for pollinators TEP 24

870.3465 Subchronic (90-day) inhalation toxicity study TGAI 24

860.1340 Residue analytical methods3 TGAI 12

875.2100 Turf transferable residue study TEP 24

 2 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850 – Ecological Effects 

Tests – including renumbering and other designations or changes for some guideline studies. See “Final Test 

Guidelines; OCSPP 850 Series; Notice of Availability” 77 FR 38282, June 27, 2012. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0028 3 The results of a radio-validation study are needed to ensure the ability of the GC/MS method GRM97.02 to 

recover aged residues.
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Table 1: Planned Data Needs for the Triclopyr Registration Review

Guideline 

Number2 Study Title1 Test 

Material

Estimated 

Timeframe

(Months 

from receipt 

of DCI)

Non-GDLN

(OECD Test 

Guideline 213)

Honey bee adult acute oral toxicity TGAI (acid) 12

Non-GDLN

(OECD Test 

Guideline 237)

Honey bee larvae acute oral toxicity TGAI (acid) 12

Non-GDLN Honey bee adult chronic oral toxicity TGAI (acid) 12

Non-GDLN Honey bee larvae chronic oral toxicity TGAI (acid) 12

Non-GDLN Residues in pollen and nectar/field residue 

analysis TGAI (acid) 24

Non-GDLN

(OECD Test 

Guidance 75)

Semi-field testing for pollinators TEP 24

Planned Data Needs for TCP Degradate

835.4300 Aerobic aquatic metabolism Degradate 24

850.1400 Fish early life stage4 Degradate 12

TGAI = technical grade active ingredient; TEP = typical end-use product

 4 Data requirement pending review of submitted study. 
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RISK ASSESSMENTS FOR REGISTRATION REVIEW

During registration review, the Agency will conduct a comprehensive ecological risk 

assessment, including an endangered species assessment, for all uses of triclopyr. For human 

health, EPA will conduct revised dietary, residential, occupational and aggregate risk 

assessments during registration review. If toxicological endpoints or points of departure are 

revised based on the data that will be required for registration review, they will be considered 

in the new assessments, as well as any changes to the standard operating procedures or 

default exposure assumptions.

Table 2 below summarizes the planned registration review risk assessments based on the 

Preliminary Problem Formulation and Human Health Assessment Scoping Document.

Table 2: Planned Risk Assessments for the Triclopyr Registration Review

Type of Risk Assessment Conduct? Notes

Ecological and Environmental Fate

Comprehensive ecological 

(species to be assessed include 

terrestrial and aquatic 

organisms), including 

endangered species 

Y 

Incidents Will check 

for updates

For a discussion of reported ecological incidents for 

triclopyr, see page 33 of the Preliminary Problem 

Formulation.

Human Health

Dietary

Food Y

Drinking water Y

Occupational

Handlers (mixers, loaders, 

applicators)

Y

Post-application Y

Residential

Handlers Y

Post-application Y

Other

Aggregate Y Evaluates the combined risk from dietary and 

residential exposures.

Cumulative N Triclopyr has not been identified as a member of a 

cumulative group that shares a common mechanism of 

toxicity.

Tolerances Y During registration review, the Agency will evaluate 

the need to harmonize tolerances with Canadian MRLs 

and the need to update the current tolerance 

expressions. 

Incidents Will check 

for updates

For a discussion of reported human incidents for 

triclopyr, see page 13 of the Human Health 

Assessment Scoping Document and the Triclopyr, 

salts and esters: Tier I Review of Human Incidents.
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TIMELINE

EPA has created the following estimated timeline for the completion of the triclopyr 

registration review in Table 3 below.

Table 3: Projected Triclopyr Registration Review Timeline

Activities Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period 2014 – December

Close Public Comment 2015 – February

Case Development

Final Work Plan 2015 – June

Issue DCI 2015 July – Sept.

Data Submission 2017 July – Sept.

60-day Public Comment Period for Draft Risk 

Assessments5

2019 January – March

Registration Review Decision

60-day Public Comment Period for Proposed 

Registration Review Decision

2019 Oct. – Dec.

Registration Review Decision and Begin PostDecision Follow-up2020

Total (years) 6

NEXT STEPS

As noted previously, the Agency plans to require several environmental fate, ecological 

effects, and human health studies for triclopyr through a Data Call-In Notice, expected to be 

issued in September 2015.

 5 The regulations governing Registration Review generally require the Agency to provide a public comment 

period of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional 

pesticides, the Agency plans to provide a 60 calendar day public comment period generally for draft risk 

assessments.