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INTRODUCTION

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

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

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

review docket (EPA-HQ-OPP-2015-0288). Cycloate belongs to the thiocarbamate family of 

herbicides. It is a systemic, broad-spectrum, and pre-emergent herbicide registered for control of 

certain grasses and broadleaf weeds in table beets, spinach, and sugar beets.

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 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 cycloate. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

There are no updates on cycloate since the PWP.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

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

on June 24, 2015 and closed on August 24, 2015, the Agency received one public comment from 

the Center for Biological Diversity. The comment does not address the timeline described in the 

PWP, but it does address the planned ecological assessment. 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.

Summarized below is the comment from the Center for Biological Diversity. 

Comments submitted by the Center for Biological Diversity (CBD) in EPA-HQ-OPP-2015-

0288-0010

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 

 

1 http://www.epa.gov/oppsrrd1/registration_review/
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cycloate 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 cycloate on endangered 

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

 

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

for cycloate 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 cycloate in connection with the development of its final registration review 

decision for cycloate.

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 workshop in April 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 cycloate 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 cycloate , EPA described the screening-level risk assessment to determine 

the potential effects of cycloate 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 

cycloate . 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 cycloate will 

describe the level of ESA analysis completed for this particular registration review case. Once the 
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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 cycloate as part of completing this 

registration review.

PLANNED DATA NEEDS

Table 1 below summarizes anticipated data needs for cycloate. For additional discussion of the 

anticipated data needs, see the Registration Review –Preliminary Problem Formulation for 

Ecological Risk and Environmental Fate, Endangered Species, and Drinking Water Assessments 

for Cycloate and Cycloate: Human Health Scoping Document in Support of Registration Review.

The table has not been updated since the PWP. 

Table 1: Anticipated Data Needs for the Cycloate Registration Review

Guideline 

Number2 Study Title

Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

Anticipated Data Needs for the Parent Cycloate

850.2100 Avian acute oral toxicity test, one passerine 

species TGAI 12

NonguidelineAvian inhalation, one species. TGAI 12

NonguidelineAcute oral toxicity to adult honey bees TGAI 12

NonguidelineAcute oral toxicity to larval honey bees TGAI 12

NonguidelineChronic oral toxicity to larval honey bees TGAI 12

NonguidelineChronic oral toxicity to adult honey bees TGAI 12

NonguidelineField trial of residues in pollen and nectar3

TEP 24

NonguidelineSemi-field testing for pollinator3

TEP 24

850.3040 Field testing for pollinators3 TEP 24

850.4500 Algal toxicity test, three species 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 The need for this anticipated data requirement is contingent on results of the tier 1 bee studies (including acute oral 

toxicity to adult honey bees, acute oral toxicity to larval honey bees, chronic oral toxicity to adult honey bees, and 

chronic oral toxicity to larval honey bees).
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Table 1: Anticipated Data Needs for the Cycloate Registration Review

Guideline 

Number2 Study Title

Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

850.4550 Cyanobacteria toxicity test TGAI 12

835.2410 Photodegradation on soil TGAI 12

835.4100 Aerobic soil metabolism (with 3 additional 

soils) 

TGAI 24

835.4300 Aerobic aquatic metabolism (with 2 systems) TGAI 24

Outstanding Data Requirements from GDCI-041301-262524

835.6100 ECM and ILV for Terrestrial Field 

Dissipation Study TEP Outstanding 

850.4100 Seedling emergence toxicity test, 10 species TEP Outstanding

850.4150 Vegetative vigor toxicity test, 10 species TEP Outstanding 

850.4400 Aquatic plant toxicity test using Lemna spp. TGAI Outstanding 

850.1035 Mysid acute toxicity test TGAI Outstanding 

850.1350 Freshwater invertebrate life-cycle test TGAI Outstanding 

850.1075 Fish acute toxicity test, marine TGAI Outstanding 

850.1400 Freshwater fish early-life stage test TGAI Outstanding 

850.2300 Avian reproduction toxicity test, two species TGAI Outstanding 

860.1900 Field Accumulation in Rotational Crops TEP Outstanding 

870.6300 Developmental Neurotoxicity Study TGAI Outstanding 

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

 

4 The studies listed in this section were previously required through a generic data call-in issued in February 2006 

and are still outstanding. These studies will not be included in the anticipated Registration Review DCI because 

they are already required through the earlier DCI.
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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 cycloate. For human health, EPA 

will conduct revised dietary, residential, and occupational risk assessments during registration 

review. If toxicological endpoints or points of departure are revised based on the data that are 

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 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 Cycloate Registration Review

Type of Risk Assessment Conduct? Notes

Comprehensive ecological 

(species to be assessed 

include terrestrial and aquatic 

organisms), including 

endangered species 

Yes The most recent comprehensive risk assessment was 

completed in 2004 for uses on table beets, sugar 

beets, and spinach. A revised assessment is necessary 

to include the data which have been and will be called 

in.

Incidents Will check for 

updates

A review of the Ecological Incident Information 

System (EIIS, version 2.1) and the Avian Monitoring 

Information System (AIMS) was completed on 

August 7, 2014, and no ecological incidents involving 

cycloate or cycloate sulfate were identified. Incident 

databases will be reviewed again at the time of the 

risk assessment.

Human Health

Dietary

Food Yes Since the acute and chronic dietary assessments and 

the drinking water estimations were conducted 

several years ago, they will need to be updated during 

Registration Review to reflect current methods, 

models and data inputs.

Drinking water Yes

Occupational

Handlers (mixers, loaders, 

applicators)

Yes There is sufficient information available to assess 

occupational handler application exposures. During 

Registration Review a new assessment of 

occupational handler exposures will be needed 

because the most recent assessment was conducted 

several years ago, and policies and data inputs and 

assumptions have changed. Also, there were risks of 

concern for some dermal and all inhalation exposures 

with varying levels of personal protective equipment 

(PPE). EPA has since updated its policy on body 

weights and updated unit exposure values, and other 

inputs for determining these risk estimates.

Post-application No

Residential

Handlers No There are no registered residential uses; therefore, no 

residential exposures are expected. However, the 

Agency will examine the need for a volatilization 
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Post-application/ bystander Yes assessment, as well as evaluate the potential for 

exposure from spray drift during Registration 

Review. Residential bystander exposures resulting 

from off-site transport (i.e., spray drift or 

volatilization) may occur as a result of occupational 

applications of cycloate. The need for a bystander risk 

assessment for cycloate will be considered during 

Registration Review.

Other

Aggregate Yes A new aggregate assessment will be needed during 

Registration Review, since the chronic dietary 

assessment and the drinking water estimations were 

conducted several years ago and they will need to be 

updated.

Cumulative No Unlike other pesticides for which EPA has followed a 

cumulative risk approach based on a common 

mechanism of toxicity, EPA has not made a common 

mechanism of toxicity finding with cycloate. 

Cycloate does not appear to produce a toxic 

metabolite produced by other substances.

Tolerances No Tolerances for cycloate are established in 40 CFR 

§180.212.

Incidents Will check for 

updates

For a discussion of reported human incidents for 

cycloate, see page 9 of the Scoping Document and the 

Cycloate: Tier I Review of Human Incidents

TIMELINE

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

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

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

Activities Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period June 2015 –

completed

Close Public Comment August 2015 -

completed

Case Development

Final Work Plan December 2015 -

completed

Issue DCI January-March 2016

Data Submission January-March 2018
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Table 3: Registration Review for Cycloate – Projected Registration Review Timeline

Activities Estimated Date

60-day Public Comment Period for Draft Risk Assessments5July-September 

2019

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision

October – December 

2020

Registration Review Decision and Begin Post-Decision Follow-up 2021

Total (years) 6

NEXT STEPS

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

effects studies for cycloate through a Data Call-In Notice, expected to be issued in early 2016. 

 

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.