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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 pyraflufen-ethyl. This work plan addresses public comments received 

on the preliminary work plan (PWP), which was posted in the pyraflufen-ethyl registration 

review docket (EPA-HQ-OPP-2014-0415). Pyraflufen-ethyl is a contact type herbicide registered 

for use as a defoliant in cotton and as a desiccant in potatoes to facilitate harvesting. Pyraflufenethyl is also registered for use as a pre-plant burn-down, on plants before crop emergence, and as 

a post-emergence treatment depending on the crop and stage of crop growth. 

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.1

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 pyraflufen-ethyl. Lastly, there is a discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

At the May 5, 2014 focus meeting for pyraflufen-ehtyl, Nichino America, the sole technical 

registrant, committed to clarify label language, where appropriate, and to provide additional 

information to inform the Agency’s assessment of this active ingredient. Nichino has recently 

submitted multiple fate and ecotoxicity studies for the E-2 and E-3 degradates of pyraflufenethyl, which the Agency is in the process of reviewing. Additional detail on the Focus Meeting 

can be found in the pyraflufen-ethyl registration review docket, Pyraflufen-ethyl: Focus Meeting 

with Nichino America Notes.

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

During the 60-day public comment period on the pyraflufen-ethyl PWP, which opened on June 

25, 2014, and closed on August 25, 2014, the Agency received two public comments. 

Comments were submitted by the FIFRA Endangered Species Task Force and the Center for 

Biological Diversity. 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 

 

1

 http://www.epa.gov/oppsrrd1/registration_review/ 
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quality concerns, and trade irritants, but no comments or information were received on those 

issues. 

Summarized below are public comments that resulted in changes to the anticipated registration 

review data needs, risk assessments, or timeline, or are of a broader regulatory nature. Public 

comments and EPA responses in their entirety are located in the docket, EPA-HQ-OPP-2014-

0415. 

Comments submitted by the Center for Biological Diversity (CBD), in EPA-HQ-OPP-2014-

0415-0011. 

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 pyraflufen-ethyl in accordance with the 

Endangered Species Act (ESA). CBD mentions 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 expressed concern regarding the rigor of the Agency’s 

preliminary determinations regarding the effects of pyraflufen-ethyl on endangered and 

threatened (listed) species and their designated critical habitat for the pyraflufen-ethyl 

registration review. 

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

opening for pyraflufen-ethyl 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 pyraflufen-ethyl in connection with the development of its final 

registration review decision for this pesticide. 

In November 2013, EPA, along with the Services and 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 

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 report2

 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 stakeholder 

workshops 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 

 

2

 http://www.nap.edu/catalog.php?record_id=18344 
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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 Report3, 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 FWP for 

pyraflufen-ethyl 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 pyraflufen-ethyl, EPA described 

the screening-level risk assessment to determine the potential effects of pyraflufen-ethyl 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 pyraflufenethyl. 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 pyraflufen-ethyl 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 pyraflufen-ethyl as part of completing this registration 

review. 

Comments submitted by FIFRA Endangered Species Task Force (FESTF), in EPA-HQOPP-2014-0415-0012. 

1. Comment: The technical registrant for pyraflufen-ethyl, as identified on the fact sheet 

included in the PWP, is Nichino America, Inc., which is a FESTF member and is entitled to 

rely on FESTF data.

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

registration review of pyraflufen-ethyl. 

PLANNED DATA NEEDS 

Table 1 below summarizes the planned data needs for pyraflufen-ethyl based on the EFED 

Registration Review Problem Formulation for Pyraflufen-ethyl and Pyraflufen-Ethyl. Human 

Health Assessment Scoping Document in Support of Registration Review. The planned data 

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

 

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 http://www.epa.gov/espp/2013/nas.html 
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Table 1: Planned Data Needs for the Pyraflufen-ethyl Registration Review 

Guideline 

Number4 Study Title2 

Test Material 

Estimated 

Timeframe 

(Months from 

receipt of DCI) 

Planned Data Needs for the Parent Pyraflufen-ethyl

850.6100 

Environmental chemistry methods and associated 

independent laboratory validations for soil, 

sediment, and water

TGAI 12 

860.1650 Submittal of Analytical Reference Standards TGAI Currently 

needed5

860.1300 Nature of the Residue – Orange6 TGAI 6 

Planned Data Needs for the Degradates E-1, E-2, E-3, and E-15

850.6100 

Environmental chemistry methods and associated 

independent laboratory validations for soil, 

sediment, and water 

Degradate E-1, 

E-2, and E-3 12 

860.1650 Submittal of Analytical Reference Standards E-15 

Metabolite 

Currently 

needed3

TGAI = technical grade active ingredient 

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 pyraflufen-ethyl. For human health, 

EPA will conduct revised dietary, residential, aggregate, 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. 

 

4

 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 5

 Previous reference standards have expired and new ones are currently needed. 

6

 Information needs to be submitted on sample storage conditions and durations for samples analyzed in the orange 

plant metabolism study (MRID 47872706). 
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Table 2: Planned Risk Assessments for the Pyraflufen-ethyl 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 Chronic estimated drinking water concentrations 

(EDWCs) will be determined by modeling the total 

toxic residues of parent and the E-1, E-2, and E-3 

degradates, noting that exposure will be mainly 

associated with E-3 as it is the most persistent 

degradate. 

Incidents Will check for 

updates 

For a discussion of reported ecological incidents for 

pyraflufen-ethyl, see page 25 of the problem 

formulation. 

Human Health 

Dietary 

Food Y A new dietary exposure and risk assessment will be 

needed during registration review to incorporate 

updated EDWCs into the chronic and cancer dietary 

exposure assessments. 

Drinking water Y 

Occupational 

Handlers (mixers, loaders, 

applicators) 

Y Occupational uses are expected to result in both shortand intermediate-term exposures. An updated 

occupational assessment will be needed to account for 

changes in occupational assessment policies (e.g., unit 

exposures and transfer coefficients) and to evaluate 

the maximum registered single application rate for 

each use site. 

Post-application Y 

Residential 

Handlers Y The agency will be considering volatilization 

exposure, as well as the potential for exposure from 

spray drift as part of the residential assessment. 

Post-application Y 

Other 

Aggregate Y Evaluates the combined risk from dietary and 

residential exposures. 

Cumulative N/A Pyraflufen-ethyl is not a member of a cumulative 

group. 

Tolerances Y The Agency anticipates updating tolerances to include 

parent and metabolites E-1 and E-9 for livestock 

commodities. 

Incidents Will check for 

updates 

Due to low frequency and severity of incident cases 

reported for pyraflufen-ethyl, there does not appear to 

be a concern at this time. For further discussion of 

reported human incidents for pyraflufen-ethyl, see 

page 10 of the Scoping Document and the Revised: 

Pyraflufen-ethyl: Tier I Review of Human Incidents. 
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TIMELINE

EPA has created the following estimated timeline for the completion of the pyraflufen-ethyl 

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

Table 3: Registration Review for Pyraflufen-ethyl – Projected Registration Review 

Timeline

Activities Estimated Date 

Opening the Docket 

Open Docket and 60-day Public Comment Period June 2014 – Completed 

Close Public Comment Aug. 2014 – Completed 

Case Development 

Final Work Plan Nov. 2014 – Completed 

Issue DCI Jan. – March 2015 

Data Submission Jan. – March 2016 

60-day Public Comment Period for Draft Risk Assessments7 July – Sept. 2017 

Registration Review Decision 

60-day Public Comment Period for Proposed Registration Review 

Decision 

April – June 2018 

Registration Review Decision and Begin Post-Decision Follow-up 2019 

Total (years) 5 

NEXT STEPS 

The Agency is requiring additional data for pyraflufen-ethyl and will issue a data call-in notice in 

early 2015. 

 

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 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.