2

Flufenpyr-ethyl Preliminary Work Plan – Table of Contents 

OVERVIEW ................................................................................................................................... 4

ANTICIPATED DATA NEEDS .................................................................................................... 5

STATUTORY AND REGULATORY AUTHORITY ................................................................... 6

CHEMICAL FACTS ...................................................................................................................... 6

USE AND USAGE INFORMATION ............................................................................................ 7

RECENT ACTIONS ....................................................................................................................... 8

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW ................................ 8

TIMELINE .................................................................................................................................... 11

NEXT STEPS ............................................................................................................................... 11

Appendix – Additional Areas Considered in the Flufenpyr-ethyl Registration Review .......... 12 

References:

This Preliminary Work Plan summarizes the Environmental Protection Agency's current position 

based on the following documents: 

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

Exposure Assessments for Flufenpyr-ethyl. Wolf, Farruggia, Louie-Juzwiak. December 4, 

2014. 

2. Flufenpyr-ethyl. Human Health Assessment Scoping Document and Preliminary Human 

Health Risk Assessment in Support of Registration Review. Tyler, Perron, Venkateshwara. 

November 26, 2014. 

3. New Chemical Review – Environmental Risk Assessment for the Proposed Uses of 

Flufenpyr Ethyl on Sugarcane and Soybeans. Carey, Nguyen, Erickson, Syslo. September 

15, 2003. 

4. Data Review and Addendum for Flufenpyr-ethyl (S-3153 WDG Herbicide) on Terrestrial 

Animals, Aquatic Organisms, and Plants. Carey, Smith. November 4, 2003. 
3

5. Flufenpyr-ethyl: Tier I Review of Human Incidents. Recore, Evans. August 20, 2014. 

These and other supporting documents for the flufenpyr-ethyl registration review case may be 

found in the docket EPA-HQ-OPP-2014-0768 at http://www.regulations.gov. 
4

OVERVIEW 

The docket for flufenpyr-ethyl is now open, initiating the first public comment period for this 

registration review (docket number 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 

light-dependent peroxidizing herbicide (LDPH). This class of herbicides is known to have a 

photo-toxic 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. 

This Preliminary Work Plan (PWP) document explains what EPA's Office of Pesticide Programs 

knows about flufenpyr-ethyl, highlighting anticipated data and assessment needs, identifying the 

types of information that would be especially useful to the Agency in conducting the review, and 

providing an anticipated timeline for completing the registration review for flufenpyr-ethyl. This 

PWP also includes a summary of the draft human health risk assessment for registration review. 

As there are no anticipated human health data needs and only minor updates were required to 

meet current assessment standards, EPA developed a combined scoping document and draft 

human health risk assessment. Both that draft human health risk assessment and this Preliminary 

Work Plan are now in the docket and a 60-day public comment period for them has commenced. 

 

The registration review process was designed to include a public participation component to 

solicit input from interested stakeholders. The Agency intends, by sharing this information in the 

docket, to inform the public of what it knows about flufenpyr-ethyl and what types of new data 

or other information would be helpful for the Agency to receive as it moves toward a decision on 

flufenpyr-ethyl. The Agency encourages all interested stakeholders to review the PWP and 

Appendix, and associated draft human health risk assessment and to provide comments and 

additional information that will help the Agency’s decision-making process for this chemical. In 

addition to general areas on which persons may wish to comment, there are some areas identified 

in the PWP and Appendix about which the Agency specifically seeks comments and information. 

Interested stakeholders could include: environmental non-profit or interest groups; pesticide 

manufacturers; agricultural labor or commodity groups; commercial, institutional, residential, 

and other users of pesticides; or the public at large. 

The Preliminary Work Plan begins by listing the anticipated data needs for flufenpyr-ethyl. 

Next, it discusses the statutory and regulatory authority for Registration Review. Then the 

document provides chemical facts, use and usage information, recent actions, the anticipated 

ecological risk assessment, a summary of the draft human health risk assessment, and a projected 

registration review timeline for flufenpyr-ethyl. Finally, the Appendix to this document includes 

identification and discussion of some areas that are considered generally in registration review 

along with some additional chemical case-specific information. 

 
5

ANTICIPATED DATA NEEDS 

Table 1 summarizes anticipated data needs for flufenpyr-ethyl. For additional discussion of the 

anticipated data needs, see 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. 

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

Guideline 

Number1 Study Title1 Test 

Material 

Estimated 

Timeframe 

(Months from 

receipt of DCI) 

Anticipated Data Needs for the Parent Flufenpyr-ethyl

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; 

 

 

1

 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 
6

STATUTORY AND REGULATORY AUTHORITY 

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All 

pesticides distributed or sold in the United States (U.S.) generally must be registered by the 

Environmental Protection Agency (EPA or the Agency), based on scientific data showing that 

they will not cause unreasonable risks to human health or the environment when used as directed 

on product labeling. 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 of no unreasonable adverse effects to human health or the 

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

Through the registration review program, the Agency periodically reevaluates pesticides to make 

sure that as change occurs, products in the marketplace can be used safely. Information on this 

program is provided on EPA’s website.2

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. The regulations governing registration review begin at 40 CFR 155.40. The 

Agency will consider benefits information and data as required by FIFRA. The public phase of 

registration review begins when the initial docket is opened for each case. The docket is the 

Agency’s opportunity to state what it knows about the pesticide and what additional risk analyses 

and data or information it believes are needed to make a registration review decision. After 

reviewing and responding to comments and data received in the docket during this initial 

comment period, the Agency will develop a Final Work Plan (FWP) and anticipated schedule for 

the registration review of flufenpyr-ethyl. 

CHEMICAL FACTS 

Table 2 provides a summary of the chemical facts for flufenpyr-ethyl. 

Table 2: Chemical Facts for Flufenpyr-ethyl

PC code 108853 

Case Number 7262 

CAS Number 188489-07-8 

Year first registered 2003 

Pesticide Type LDPH 

Chemical class Pyridazinone 

Reregistration Eligibility 

Decision (RED) 

Because it was registered after November 1984, flufenpyr-ethyl 

was not subject to reregistration. 

Tolerance Reassessment 

Eligibility Decision 

(TRED) 

Not applicable due to flufenpyr-ethyl’s recent registration. 

 

2

 http://www.epa.gov/oppsrrd1/registration_review/ 
7

Table 2: Chemical Facts for Flufenpyr-ethyl

Cumulative group Not applicable. Flufenpyr-ethyl has not been identified as a 

member of a cumulative group that shares a common mechanism 

of toxicity. 

40 CFR Citation Tolerances for flufenpyr-ethyl are established in 40 CFR 

§180.595. 

Dual-use Flufenpyr-ethyl is registered for conventional pesticidal uses only 

and has no registered antimicrobial or biopesticidal uses. 

Non-pesticidal uses There are no identified non-pesticidal uses of flufenpyr-ethyl. 

Pesticide Re-evaluation 

Division, Chemical 

Review Manager 

Steven Snyderman, snyderman.steven@epa.gov, 703-347-0249 

Registration Division, 

Product Manager 

Kathryn Montague, montague.kathryn@epa.gov, 703-305-1243 

USE AND USAGE INFORMATION 

Table 3 summarizes the use information for flufenpyr-ethyl based on the 2003 registration 

action. 

Table 3: Flufenpyr-ethyl Use and Usage Information

Summary of Use Flufenpyr-ethyl is a contact herbicide registered for the postemergence control of broadleaf weed species. 

Use Sites Agricultural use on field corn, sugarcane, and soybeans. No 

residential or public recreational area uses. 

Summary of Usage EPA data sources do not reflect any usage of flufenpyr-ethyl 

since its original registration in 2003. 

Formulation Type(s) Formulated as a water dispersible granular. 

Application Method(s) Products can be applied by tractor mounted conventional ground 

sprayer, soil band treatment, soil broadcast, direct spray, and 

aerial application. 

Technical Registrant(s) Valent U.S.A. Corporation 

No. of Registrations Two Section 3 products3

Restricted Use No 

Guidance for Commenters: Additional areas of use and usage related information

requested for this registration review, and of particular interest to EPA, are described below. 

 Confirmation of the following label information: sites of application; formulations; 

application methods and equipment; maximum application rates; frequency of 

application, application intervals, and maximum number of applications per season; and 

geographic limitations on use. 

 

3

 Section 3 product labels can be obtained from the Pesticide Product Label System (PPLS) website 

(http://oaspub.epa.gov/pestlabl/ppls.home). 
8

 Use distribution (e.g., acreage and geographical distribution of relevant use sites). 

 Median and 90th percentile reported use rates (lbs ai/A) from usage data – national, state, 

and county. 

 Typical application timing (date of first application and application intervals) – national, 

state, and county. 

 Usage/use information for non-agricultural uses. 

 Typical application interval (days). 

 State or local use restrictions. 

 Foreign technical registrants not listed above who supply technical flufenpyr-ethyl to the 

US market. 

RECENT ACTIONS 

There are no recent actions for flufenpyr-ethyl. 

ANTICIPATED 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 anticipates the need to conduct a revised aquatic animal 

risk assessment, a risk assessment for pollinators, and an endangered species assessment for all 

uses of flufenpyr-ethyl. 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 

assessment, as well as any changes to the standard operating procedures or default exposure 

assumptions. 

Table 4 below summarizes the recently completed draft human health risk assessment and the 

anticipated ecological and environmental fate risk assessment for registration review. 
9

Table 4: Anticipated 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/ed? 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 flufenpyrethyl. 

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 postapplication 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 
10

Table 4: Anticipated 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/ed? Notes

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. 

Guidance for Commenters: Additional ecological information requested for this 

registration review, and of particular interest to EPA, is described below. 

 Ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and 

mammalian mortalities) not already reported to the Agency. 

 Water quality monitoring data (see Appendix for further details). 
11

TIMELINE 

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

registration review in Table 5 below. 

Table 5: Projected Flufenpyr-ethyl Registration Review Timeline

Activities Estimated Date

Opening the Docket 

Open Docket and 60-day Public Comment Period4 2014 – December 

Close Public Comment 2015 – February 

Case Development 

Final Work Plan 2015 – May 

Issue DCI 2015 July – Sept. 

Data Submission 2017 July – Sept. 

60-day Public Comment Period for Draft Risk 

Assessments5, 6

2019 Jan. - March 

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 

After the 60-day public comment period closes, the Agency will review and respond to any 

comments received in a timely manner and then issue a Final Work Plan for the registration 

review of flufenpyr-ethyl. 

 

 

4

 The Agency is seeking comment on the PWP and the draft human health risk assessment during this comment 

period. 

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. 

6

 The Agency expects to seek comment on the draft ecological and environmental fate risk assessments at this time. 
12

Appendix – Additional Areas Considered in the Flufenpyr-ethyl Registration 

Review 

PUBLIC COMMENTS AND FEEDBACK: 

Guidance for Commenters: The areas below highlight topics of special interest to the Agency 

where your comments, data submissions, or reference to sources of additional information could 

be of particular use.

Trade Irritants: 

Through the registration review process, the Agency intends to solicit information on trade 

irritants and, to the extent feasible, take steps toward facilitating irritant resolution. The Agency 

will work to harmonize tolerances and international maximum residue limits (MRLs) and may 

modify tolerance levels to do so, when possible. Growers and other stakeholders are asked to 

comment on any trade irritant issues resulting from lack of MRLs or disparities between U.S. 

tolerances and MRLs in key export markets, providing as much specificity as possible regarding 

the nature of the concern. 

Water Quality: 

Flufenpyr-ethyl is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act.7

 In addition, no Total Maximum Daily Loads 

(TMDL) have been developed for flufenpyr-ethyl.8 More information on impaired water bodies 

and TMDLs can be found at the Agency’s website.9 The Agency invites submission of water 

quality data for this pesticide. To the extent possible, data should conform to the quality 

standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired 

Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and 

Management Process10 in order to ensure they can be used quantitatively or qualitatively in 

pesticide risk assessments. 

Environmental Justice: 

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all 

people, regardless of race, color, national origin, or income, in the development, implementation, 

and enforcement of environmental laws, regulations, and policies. To help address potential 

environmental justice issues, the Agency seeks information on any groups or segments of the 

population who, as a result of their location, cultural practices, or other factors, may have 

atypical, unusually high exposure to flufenpyr-ethyl compared to the general population. Please 

comment if you are aware of any sub-populations that may have atypical, unusually high 

exposure compared to the general population.

 

7 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

8

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES 9 http://www.epa.gov/owow/tmdl/

10 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
13

ENDANGERED SPECIES: 

A risk assessment that supports a complete endangered species determination has not been 

conducted for flufenpyr-ethyl. The ecological risk assessment planned during registration review 

will allow the Agency to determine whether use of flufenpyr-ethyl has “no effect” or “may 

affect” federally listed threatened or endangered species (listed species) or their designated 

critical habitats. When an assessment concludes that a pesticide’s use “may affect” a listed 

species or its designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife 

Service and/or National Marine Fisheries Service (the Services), as appropriate. 

ENDOCRINE DISRUPTOR SCREENING PROGRAM: 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 

chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of its most recent registration decision for flufenpyr-ethyl, EPA 

reviewed these data and selected the most sensitive endpoints for relevant risk assessment 

scenarios from the existing hazard database. However, as required by FFDCA section 408(p), 

flufenpyr-ethyl is subject to the endocrine screening part of the Endocrine Disruptor Screening 

Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between 

October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 

chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. A second list 

of chemicals identified for EDSP screening was published on June 14, 201311 and includes some 

 

11 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals. 
14

pesticides scheduled for registration review and chemicals found in water. Neither of these lists 

should be construed as a list of known or likely endocrine disruptors. 

For further information on the status of the EDSP, the policies and procedures, the lists of 

chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our 

website.12

HUMAN STUDIES: 

Occupational 

Past flufenpyr-ethyl risk assessments rely in part on data from studies in which adult human 

subjects were intentionally exposed to a pesticide to determine their dermal and inhalation 

exposure. Many such studies, involving exposure to many different pesticides, comprise generic 

pesticide exposure databases such as the Pesticide Handlers Exposure Database (PHED), the 

Agricultural Handler Exposure Task Force (AHETF) database, and the Agricultural Reentry 

Task Force (ARTF) Database. EPA has reviewed all the studies supporting these multi-pesticide 

generic exposure databases, and has found no clear and convincing evidence that the conduct of 

any of them was either fundamentally unethical or significantly deficient relative to the ethical 

standards prevailing at the time the research was conducted. All applicable requirements of 

EPA’s Rule for the Protection of Human Subjects of Research (40 CFR Part 26) have been 

satisfied, and there is no regulatory barrier to continued reliance on these studies. 

 

12 http://www.epa.gov/endo/