INTRODUCTION

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

the registration review of triallate. This work plan addresses public comments received 

concerning the Preliminary Work Plan (PWP), which was posted in the triallate registration 

review docket (EPA-HQ-OPP-2014-0573). Triallate is a pre-emergent herbicide registered for 

agricultural use in barley, Bermudagrass (grown for seed and hay), lentils, peas (dried and 

succulent), triticale, sugar beets, and wheat to control certain types of weeds such as wild oat, 

bromegrass, Japanese brome, cheat, downy brome, yellow foxtail, pigeon grass, green foxtail, 

and annual ryegrass. 

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.0F

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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 anticipated 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 triallate. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

The public comments received on the PWP did not result in any changes to the anticipated data 

requirements listed in the PWP; however, the list of planned data requirements has been updated 

in the FWP to include Tier 2 pollinator studies (semi-field testing for pollinators, residues in 

pollen and nectar/field residue analysis, and 850.3040 field testing for pollinators). The need for 

these additional Tier 2 pollinator studies is contingent on results of the Tier 1 bee studies (adult 

honeybee chronic oral toxicity, larval honeybee acute oral toxicity, and larval honeybee chronic 

oral toxicity).

There are no additional updates on triallate since the PWP.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

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

on September 24, 2014 and closed on November 24, 2014, the Agency received comments from 

three stakeholders. Comments were submitted by the Center for Biological Diversity (CBD), the 

FIFRA Endangered Species Task Force (FESTF), and Gowan Company (Gowan), the triallate 

1 http://www.epa.gov/oppsrrd1/registration_review/

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technical registrant. The comments do not address the timeline described in the PWP, but they do 

address the planned ecological 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, but no comments or information were received on those issues.

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. 

Public comments and EPA responses in their entirety are located in the docket, EPA-HQ-OPP2014-0573. Detailed Agency responses to Gowan’s comments, which pertain to environmental 

fate properties derived from available aerobic soil metabolism and aerobic aquatic metabolism 

studies as discussed in the Registration Review Problem Formulation for Triallate, are provided 

in a separate memo titled Response to Gowan Company’s Comments on Environmental Fate 

Data Cited in the EFED Registration Review Problem Formulation for Triallate.

Comments submitted by CBD in EPA-HQ-OPP-2014-0573-0008.

1. Comment: The Center for Biological Diversity’s (CBD) comments focus on the EPA’s duty 

to consult with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service 

(the Services) on the registration review of triallate in accordance with the Endangered 

Species Act (ESA). The CBD comments mention various aspects of the risk assessment 

process, including use of the best available data to develop endangered species risk 

assessments, and evaluation of effects on endangered and threatened species and their 

designated critical habitat. CBD also expresses concern regarding the rigor of the Agency’s 

preliminary determinations regarding the effects of triallate on endangered and threatened 

(listed) species and their designated critical habitat for the triallate registration review. 

Response: EPA has reviewed the comments from CBD on the registration review docket 

opening for triallate and plans to address many of the concerns raised by CBD as part of the 

implementation plan for assessing the risks of pesticides to listed species based on the 

recommendations of the April 2013 National Academy of Sciences (NAS) report. EPA will 

address concerns specific to triallate in connection with the development of its final 

registration review decision for triallate.

In November 2013, the EPA, along with the Services and the USDA, released a summary of 

their joint Interim Approaches for assessing risks to endangered and threatened (listed) 

species from pesticides. The Interim Approaches were developed jointly by the agencies in 

response to the National Academy of Sciences’ (NAS) recommendations and reflect a 

common approach to risk assessment shared by the agencies as a way of addressing scientific 

differences between the EPA and the Services. The NAS report outlines recommendations on 

specific scientific and technical issues related to the development of pesticide risk 

assessments that EPA and the Services must conduct in connection with their obligations 

under the ESA and FIFRA.

The joint Interim Approaches were released prior to a stakeholder workshop held on 

November 15, 2013. In addition, the EPA presented the joint Interim Approaches at the 

December 2013 Pesticide Program Dialogue Committee (PPDC) and State-FIFRA Issues 

Research and Evaluation Group (SFIREG) meetings. The agencies also held a stakeholder 

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workshops in April 2014 and October 2014, allowing additional opportunities for 

stakeholders to comment on the Interim Approaches. Additional workshops are planned to 

enhance stakeholder involvement. As part of a phased, iterative process for developing the 

Interim Approaches, the agencies will also consider public comments on the Interim 

Approaches in connection with the development of upcoming Registration Review 

decisions. The details of the joint Interim Approaches are contained in the white paper

“Interim Approaches for National-Level Pesticide Endangered Species Act Assessments 

Based on the Recommendations of the National Academy of Sciences April 2013 Report,” 

dated November 1, 2013.

Given that the agencies are continuing to develop and work toward implementation of the 

Interim Approaches to assess the potential risks of pesticides to listed species and their 

designated critical habitat, the ecological problem formulation supporting this Final Work 

Plan for triallate does not describe the specific ESA analysis, including effects 

determinations for specific listed species or designated critical habitat, to be conducted 

during registration review. In the ecological problem formulation document for triallate, EPA 

described the screening-level risk assessment to determine the potential effects of triallate on 

all taxa of non-target wildlife and plants, which will assume that listed species and their 

designated critical habitats may be present in the vicinity of the application of triallate. This 

screening-level assessment will allow EPA to focus its future evaluations on the types of 

species where the potential for effects exists once the scientific methods being developed by 

the agencies have been fully vetted. While the agencies continue to develop a common 

method for ESA analysis, the planned screening-level risk assessment for the registration 

review of triallate will describe the level of ESA analysis completed for this particular 

registration review case. Once the agencies have fully developed and implemented the 

scientific methods necessary to complete risk assessments for endangered and threatened 

(listed) species and their designated critical habitats, these methods will be applied to 

subsequent analyses for triallate as part of completing this registration review. 

Comments submitted by FESTF in EPA-HQ-OPP-2014-0573-0010.

2. Comment: “The technical registrant, as identified on the fact sheet included in the 

Registration Review work plan, is Gowan Company, which is an FESTF member and is 

entitled to rely on FESTF data.”

Response: The Agency thanks FESTF for the comment and will consider this information 

during registration review.

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PLANNED DATA NEEDS

Table 1 below summarizes the data needs for triallate and for the degradate 2,3,3-trichloro-2-

propenesulfonic acid (TCPSA). In addition, submittal of analytical reference standards will be 

required for TCPSA. The current stock of TCPSA standards available in the EPA National 

Pesticide Standards Repository has expired. Analytical reference standards of TCPSA will be 

required to be provided to the Repository with an updated certificate of analysis (COA), or new 

materials sent to the Repository. For additional discussion of the anticipated data needs or the 

required submittal of analytical reference standards, see the Registration Review Problem 

Formulation for Triallate and Triallate Human Health Risk Assessment Scoping Document in 

Support of Registration Review.

The public comments received on the PWP did not result in any changes to the anticipated data 

requirements listed in the PWP; however, the following list of planned data requirements has 

been updated in the FWP to include Tier 2 pollinator studies (semi-field testing for pollinators, 

residues in pollen and nectar/field residue analysis, and 850.3040 field testing for pollinators). 

The need for these additional Tier 2 pollinator studies is contingent on results of the Tier 1 bee 

studies (adult honeybee chronic oral toxicity, larval honeybee acute oral toxicity, and larval 

honeybee chronic oral toxicity).

Table 1: Planned Data Needs for the Triallate Registration Review

Guideline Number1F

2 Study Title1

Test Material

Estimated 

Timeframe

(Months from 

receipt of 

DCI)

835.4400 Anaerobic aquatic metabolism TGAI 24

850.6100

Environmental chemistry methods and 

associated independent laboratory 

validations for water and soil

TGAI and 

the degradate 

2,3,3-trichloro-2-

propenesulfonic 

acid (TCPSA)

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850.1025 Acute toxicity estuarine and marine 

organisms (oyster shell growth)2F

3 TGAI 12

850.1035 Acute toxicity estuarine and marine 

organisms (mysid) TGAI 12

850.1045 Acute toxicity estuarine and marine 

organisms (penaeid)3 TGAI 12

850.1055 Acute toxicity estuarine and marine 

organisms (bivalve)3 TGAI 12

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 Data for only one invertebrate mollusk is necessary. Data maybe generated for either the oyster (GLN 850.1025), 

penaeid (850.1045), or bivalve (850.1055).

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Table 1: Planned Data Needs for the Triallate Registration Review

Guideline Number1F

2 Study Title1

Test Material

Estimated 

Timeframe

(Months from 

receipt of 

DCI)

850.1075 Acute toxicity estuarine and marine 

organisms (saltwater fish) TGAI 12

850.1350 Saltwater invertebrate life cycle TGAI 12

850.1400 Saltwater fish early-life stage TGAI 12

850.4550 Cyanobacteria toxicity TGAI 12

850.2100 Avian acute oral toxicity (passerine 

species) TGAI 12

850.2300 Avian reproduction (waterfowl) TGAI 24

Non-guideline (GDLN) 

Special Study Honeybee adult chronic oral toxicity TGAI 12

Non-GDLN Special Study Honeybee larval acute oral toxicity TGAI 12

Non-GDLN Special Study Honeybee larval chronic oral toxicity TGAI 12

Non-GDLN Special Study Semi-field testing for pollinators3F

4 TEP 12

Non-GDLN Special Study Residues in pollen and nectar/Field 

residue analysis4 TEP 24

850.3040 Field testing for pollinators4 TEP 36

Non-GDLN Special Study Whole sediment: chronic invertebrates 

freshwater, Chironomus dilutus TGAI 24

Non-GDLN Special Study Whole sediment: chronic invertebrates 

freshwater, Hyalella azteca TGAI 24

Non-GDLN Special Study Whole sediment: chronic invertebrates 

marine, Leptocheirus plumulosus TGAI 24

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

4 The need for this anticipated data requirement is contingent on results of the tier 1 bee studies (including adult 

honeybee chronic oral toxicity, larval honeybee acute oral toxicity, and larval honeybee chronic oral toxicity).

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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 triallate. For human health, EPA will

conduct an updated drinking water assessment and will also consider the need for a residential 

bystander assessment. If toxicological endpoints or points of departure are revised based on the 

data that are anticipated to be required for registration review, they will be considered in the new 

assessments, as will any changes to the standard operating procedures or default exposure 

assumptions. EPA does not anticipate conducting updated dietary, residential, occupational, or 

aggregate assessments during registration review, unless there are significant changes to the 

points of departure, estimated drinking water concentrations, uncertainty factors, or safety 

factors. 

Table 2 on the following page summarizes the planned registration review risk assessments 

based on the EFED Problem Formulation and HED Scoping Document. The planned 

assessments have not changed from what was included in the PWP.

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Table 2: Planned Risk Assessments for the Triallate 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 

Yes EPA anticipates conducting an updated 

comprehensive ecological risk assessment during 

registration review. The new assessment will 

incorporate the most up-to-date modeling 

methodologies, updated toxicological endpoints, and 

data submitted under the anticipated registration 

review Data Call-In Notice. 

Incidents Will check for 

updates

For a discussion of reported ecological incidents for 

triallate, see page 14 of the Problem Formulation.

Human Health

Dietary

Food No The most recent dietary exposure assessment was 

conducted for the 2008 human health risk 

assessment. No dietary risks of concern were 

identified. EPA does not anticipate conducting an 

updated dietary assessment for registration review 

unless there are significant changes to the drinking

water estimated concentrations or if there are 

significant changes to the points of departure, 

uncertainty factors, or safety factors.

Drinking water Yes EPA anticipates conducting an updated drinking 

water assessment during registration review to 

incorporate updated estimated drinking water 

concentrations.

Occupational

Handlers (mixers, loaders, 

applicators)

No The most recent occupational exposure assessment 

was conducted for the 2008 human health risk 

assessment. All of the handler exposure and postapplication exposure non-cancer risk estimates were 

below the level of concern with the PPE required on 

triallate labels. EPA does not anticipate conducting 

an updated occupational assessment during 

registration review unless warranted by any changes 

to policy or points of departure.

Post-application No

Residential

Handlers No There are no residential uses registered for triallate.

Post-application Yes Residential bystander exposure resulting from offsite transport (i.e., spray drift or volatilization) may 

occur as a result of occupational applications of 

triallate. The need for a bystander risk assessment 

will be considered during registration review.

Other

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Aggregate No An aggregate assessment evaluates the combined risk

from dietary and residential exposures. 

The most recent aggregate assessment was conducted 

for the 2008 human health risk assessment. No risks 

of concern were identified. EPA does not anticipate 

conducting an updated aggregate risk assessment for 

registration review unless there are significant 

changes to the toxicological points of departure, 

uncertainty factors, dietary exposure estimates, or 

estimated drinking water concentrations.

Cumulative No Not applicable. Triallate has not been identified as a 

member of a cumulative group that shares a common 

mechanism of toxicity. 

Triallate is a member of the thiocarbamate class of 

pesticides; however, EPA has determined that the 

thiocarbamate pesticides should not undergo 

cumulative assessments since chemicals in the group 

do not act the same way in the body. In late 2001 

and early 2002, EPA provided an opportunity for the 

public to comment on the Agency’s common 

mechanism determinations for the thiocarbamates, 

which also belong to the carbamate group of 

pesticides. EPA determined that the thiocarbamates 

do not share a common mechanism of toxicity. 

Therefore, a cumulative risk assessment has not been 

performed.

Tolerances Update The tolerance expressions for triallate should be 

revised during registration review. Please refer to 

page 12 of the HED Scoping Document.

Incidents Will check for 

updates

EPA has evaluated the available incident data and 

concludes that there does not appear to be a concern 

at this time that would warrant further investigation, 

since there were no incidents involving triallate 

reported to either IDS or SENSOR-Pesticides. The 

Agency will continue to monitor the incident 

information and if a concern is triggered, additional 

analysis will be included in the risk assessment. 

See page 12 of the Scoping Document and the 

Triallate Tier I Review of Human Incidents.

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TIMELINE

EPA has created the following estimated timeline for the completion of the triallate registration

review in Table 3 below. The projected timeline has not changed since the PWP.

Table 3: Registration Review for Triallate – Projected Registration Review Timeline

Activity Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period Completed 

September 2014

Close Public Comment Completed 

November 2014

Case Development

Final Work Plan Completed 

March 2015

Issue DCI 2015 – April - June

Data Submission 2017 – April - June

60-day Public Comment Period for Draft Risk Assessments4F

5 2018 – Oct. – Dec.

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision

2019 – July – Sept.

Registration Review Decision and Begin Post-Decision Follow-up 2020

Total (years) 6

NEXT STEPS

As noted previously, the Agency plans to require several ecological effects studies for triallate

through a Data Call-In Notice, expected to be issued in mid-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.

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