INTRODUCTION

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

the registration review of flufenpyr-ethyl. This work plan addresses public comments received 

concerning the Preliminary Work Plan (PWP), which was posted in the flufenpyr-ethyl

registration review docket (EPA-HQ-OPP-2014-0768). Flufenpyr-ethyl is a contact herbicide 

currently registered for the post-emergence control of broadleaf weed species, and is a lightdependent peroxidizing herbicide (LDPH). This class of herbicides is known to have a phototoxic mode of action in plants and possibly in animals. LDPHs may be more toxic to plants and 

aquatic animals when exposed to natural sunlight, such as exposure conditions in the field. 

Flufenpyr-ethyl is formulated as a water dispersible granular. Application equipment and 

methods for flufenpyr-ethyl include ground application, soil band treatment, soil broadcast, 

direct spray, and aerial application. Flufenpyr-ethyl is registered for use on field corn, soybeans, 

and sugarcane. There are no registered residential uses for any flufenpyr-ethyl product.

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

UPDATES SINCE THE PWP WAS ISSUED

After the PWP was issued, the Agency received a formal request from Valent U.S.A. 

Corporation, the sole registrant, requesting voluntary cancellation of all existing registrations for 

products containing the active ingredient flufenpyr-ethyl. In the near future, the Agency intends 

to announce receipt of this request in a Federal Register Notice and take comment for a 30-day 

period. If the Agency does not receive any substantive comments during this period, EPA will 

grant the request for voluntary cancellation in a subsequent cancellation order.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

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

opened on December 19, 2014 and closed on February 17, 2015, the Agency received two public 

comments. Comments were submitted by the FIFRA Endangered Species Task Force and the 

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

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Center for Biological Diversity. The comments do not address the timeline described in the 

PWP, but they do address the planned ecological risk assessments. 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 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-

0768.

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

0768-0008.

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 flufenpyr-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 flufenpyr-ethyl on endangered and 

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

registration review. 

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

opening for flufenpyr-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 flufenpyr-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 

2 http://www.nap.edu/catalog.php?record_id=18344

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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 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 

flufenpyr-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 flufenpyr-ethyl, EPA described 

the screening-level risk assessment to determine the potential effects of flufenpyr-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 flufenpyr-ethyl. 

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 flufenpyr-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 flufenpyr-ethyl as part of completing this registration review.

Comments submitted by FIFRA Endangered Species Task Force (FESTF), in EPA-HQOPP-2014-0768-0009.

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

included in the PWP, is Valent U.S.A. Corporation, 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 flufenpyr-ethyl.

3 http://www.epa.gov/espp/2013/nas.html

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PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for flufenpyr-ethyl based on the Registration 

Review – Problem Formulation for the Ecological Risk and Drinking Water Exposure 

Assessments for Flufenpyr-ethyl and Flufenpyr-ethyl. Human Health Assessment Scoping 

Document and Preliminary Human Health Risk Assessment in Support of Registration Review.

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

Table 1: Planned Data Needs for the Flufenpyr-ethyl Registration Review

Guideline 

Number4 Study Title2

Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

NonGuideline Honey bee adult acute oral toxicity TGAI 12

NonGuideline Honey bee adult chronic oral toxicity TGAI 12

NonGuideline Honey bee larval acute oral toxicity TGAI 12

NonGuideline Honey bee larval chronic oral toxicity TGAI 12

NonGuideline Semi-field testing for pollinators TEP or TGAI 24

NonGuideline Field trial of residues in pollen and nectar TEP 24

850.3040 Field testing for pollinators TEP 24

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

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

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RISK ASSESSMENTS FOR REGISTRATION REVIEW

The most recent ecological and environmental fate risk assessment was completed in 2003 when 

flufenpyr-ethyl was registered as a new chemical with EPA. A comprehensive human health risk 

assessment for flufenpyr-ethyl was completed on November 26, 2014, prior to which the most 

recent human health risk assessment was completed in 2003 for flufenpyr-ethyl’s initial 

registration. Findings and conclusions from these risk assessments are summarized in the 

Registration Review – Problem Formulation for the Ecological Risk and Drinking Water 

Exposure Assessments for Flufenpyr-ethyl and Flufenpyr-ethyl. Human Health Assessment 

Scoping Document and Preliminary Human Health Risk Assessment in Support of Registration 

Review.

During registration review, the Agency will conduct a revised aquatic animal risk assessment, a 

risk assessment for pollinators, and an endangered species assessment for all uses of flufenpyrethyl. If toxicological endpoints or points of departure are revised based on the data that are 

planned to be required for registration review, they will be considered in the new assessment, as 

well as any changes to the standard operating procedures or default exposure assumptions.

Table 2 below summarizes the recently completed draft human health risk assessment and the 

planned ecological and environmental fate risk assessment for registration review.

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Table 2: Planned Ecological and Environmental Fate Risk Assessments and Summary of Draft 

Human Health Risk Assessment for the Flufenpyr-ethyl Registration Review

Type of Risk Assessment Conduct? Notes

Ecological and Environmental Fate

Ecological risk assessment for 

aquatic organisms, 

pollinators, and an 

endangered species biological 

evaluation

Y

Incidents Will check for 

updates

There are no reported ecological incidents for 

flufenpyr-ethyl.

Human Health

Dietary

Food Y An updated chronic dietary (food and drinking water) 

exposure and risk assessment was conducted. The 

chronic dietary exposure estimates were below the 

Agency’s level of concern (LOC) for the general U.S. 

population and all population subgroups.

Drinking water Y

Occupational

Handlers (mixers, loaders, 

applicators)

Y An updated occupational exposure assessment for 

flufenpyr-ethyl was conducted for mixers/loaders, 

applicators, and flaggers for aerial and groundboom 

applications. Inhalation risk estimates were not of 

concern. EPA assessed only inhalation exposures 

since a dermal hazard was not identified.

Post-application N The Agency did not assess post-application dermal 

exposures since a dermal hazard was not identified. 

Post-application inhalation exposures were not 

assessed either as the handler inhalation exposure 

estimates are expected to be protective of most 

occupational post-application inhalation exposure 

scenarios.

Residential

Handlers N There are no proposed or registered products 

containing flufenpyr-ethyl that would result in 

residential handler exposure as there are no registered 

residential uses. Therefore, a conventional residential 

exposure assessment was not performed. However, a 

quantitative spray drift assessment was conducted and 

risk estimates from ground boom and aerial 

applications are not of concern. 

Post-application Y

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Other

Aggregate Y As there are no registered residential uses, the 

aggregate risk assessment is equivalent to the chronic 

dietary assessment. The chronic aggregate (food + 

drinking water) exposure and risk estimates did not 

exceed the Agency’s LOC.

Cumulative N EPA has not made a common mechanism of toxicity 

finding as to flufenpyr-ethyl and any other substances 

and flufenpyr-ethyl does not appear to produce a toxic 

metabolite produced by other substances. Therefore, 

EPA has assumed that flufenpyr-ethyl does not have a 

common mechanism of toxicity with other 

substances.

Tolerances Y The tolerance expression for flufenpyr-ethyl was 

reviewed and recommendations for updates were 

made on page 7 of Flufenpyr-ethyl. Human Health 

Assessment Scoping Document and Preliminary 

Human Health Risk Assessment in Support of 

Registration Review.

Incidents Will check for 

updates

There were no incidents involving flufenpyr-ethyl 

reported to either OPP Incident Data System (IDS) or 

Sentinel Event Notification System for Occupational 

Risk (SENSOR)-Pesticides for the time period from 

1998 to 2010.

TIMELINE

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

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

Table 3: Projected Flufenpyr-ethyl Registration Review Timeline

Activities Estimated Date

Opening the Docket

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

Completed

Close Public Comment February 2015 –

Completed

Case Development

Final Work Plan May 2015 – Completed

Issue DCI 2015 July – Sept.

Data Submission 2017 July – Sept.

60-day Public Comment Period for Draft Risk Assessments5 2019 Jan. - March

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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Table 3: Projected Flufenpyr-ethyl Registration Review Timeline

Activities Estimated Date

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision

2019 Oct. – Dec.

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

Total (years) 6

NEXT STEPS

As noted previously, EPA intends to issue in the Federal Register a notice of receipt of request to 

voluntarily cancel all existing registrations for products containing the active ingredient 

flufenpyr-ethyl. The Agency will take comment on this request for a 30-day period. If the 

Agency does not receive any substantive comments during this period, EPA will grant the 

request for voluntary cancellation in a subsequent cancellation order. Should the request not be 

granted, the Agency plans to continue with the registration review of flufenpyr-ethyl and require 

several ecological effects studies through a Data Call-In Notice, expected to be issued in 2015. 

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