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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 fenhexamid. This work plan addresses public comments received 

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

review docket (EPA-HQ-OPP-2013-0187). The fungicide fenhexamid is a water dispersible 

granule that is applied on a variety of agricultural and ornamental crops in the field, greenhouses, 

and in post-harvest production. Specific agricultural use sites are almonds, asparagus, 

bushberries, caneberries, cilantro, cherries, cucumbers, flavoring/spice crops, fruiting vegetables, 

ginseng, grapes, kiwi fruit, leafy greens (except spinach), pears, pistachios, pomegranates, 

raspberries, stone fruits, strawberries, and tomatoes.

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

UPDATES SINCE THE PWP WAS ISSUED

There are no additional updates on fenhexamid since the PWP.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

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

opened on June 26, 2013 and closed on August 26, 2013, the Agency received three public 

comments. Comments were submitted by Arysta LifeScience, the Western Integrated Pest 

Management Center (WIPMC), and the FIFRA Endangered Species Task Force. The comment 

from WIMPC provided the Agency with additional use, distribution, application, and MRL 

information which stressed the importance of fenhexamid in Integrated Pest Management (IPM) 

practices throughout the western states of California, Oregon, Washington, and Utah. 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 quality concerns, and 

trade irritants, but no comments or information were received on those issues.

 1 http://www.epa.gov/oppsrrd1/registration_review/
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Public comments are located in the docket, EPA-HQ-OPP-2013-0187. No comments resulted in 

changes to the anticipated registration review data needs, risk assessments, or timeline. The 

Agency thanks all commenters for their comments and will consider the information provided 

during registration review.

PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for fenhexamid based on the Registration 

Review – Preliminary Problem Formulation for Ecological Risk and Environmental Fate, 

Endangered Species, and Drinking Water Assessments for Fenhexamid (PC Code 090209) and 

Fenhexamid Human Health Assessment Scoping Document 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 Fenhexamid Registration Review

Guideline 

Number2 Study Title2

Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

835.4100 Aerobic soil metabolism TGAI 24

835.4300 Aerobic aquatic metabolism TGAI 24

835.4400 Anaerobic aquatic metabolism TGAI 24

835.6100 Terrestrial field dissipation TEP 24

850.6100

Environmental chemistry methods and associated 

independent laboratory validation for soil TGAI 24 Environmental chemistry methods and associated 

independent laboratory validation for water

850.1730 Fish bioconcentration factor (BCF) TGAI 12

850.1025 Acute toxicity estuarine and marine organisms, 

oysters TGAI 12

850.1035 Acute toxicity estuarine and marine organisms, 

crustacean

TEP 12

850.1350 Aquatic invertebrate life cycle (saltwater), 

reproduction test TGAI 12

850.1735 Whole sediment: acute freshwater invertebrates, 

Chironomus dilutus and Hyalella azteca TGAI 12

850.1740 Whole sediment: acute marine invertebrates, 

Leptocheirus plumulosus TGAI 12

850.2100 Avian oral toxicity, passerine species TGAI 12

850.4100 Terrestrial plant toxicity, seedling emergence (10 

species) TEP 12

850.4150 Terrestrial plant toxicity, vegetative vigor (10 

species) TEP 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
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Table 1: Planned Data Needs for the Fenhexamid Registration Review

Guideline 

Number2 Study Title2

Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

850.4500 Aquatic plant growth (algal toxicity) freshwater 

diatom TEP 12

850.4500 Aquatic plant growth (algal toxicity) marine diatom TEP 12

850.4550 Aquatic plant, cyanobacterium TEP 12

870.7800 Immunotoxicity3 TGAI 12

Non-GDLN 

Special Study

Whole sediment: chronic invertebrates freshwater, 

Chironomus dilutus and Hyalella azteca TGAI 24

Non-GDLN 

Special Study

Whole sediment: chronic invertebrates marine, 

Leptocheirus plumulosus TGAI 24

Non-GDLN 

Special Study Honeybees, acute oral toxicity TGAI 12

Non-GDLN 

Special Study Honeybee, larval toxicity test TGAI 12

Planned Data Needs for the C-C Biphenyl Dimer, M4, and WAK 7004 (7-Chloro-2-(1-

methylcyclohexyl)-1,3-benzoxazol-6-ol) Degradates

835.6100 Terrestrial field dissipation, major degradates TEP 24

850.6100

Environmental chemistry methods and associated 

independent laboratory validation for soil, major 

degradates TGAI 24 Environmental chemistry methods and associated 

independent laboratory validation for water, major 

degradates

Outstanding Data Requirements from Conditional Registration(s)4

835.6100 Terrestrial Field Dissipation5 TEP Submitted -

Supplemental

850.1730 Fish BCF TGAI

Waiver request 

submitted, but not 

granted6

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

 3 Recently, OPP published the findings of its retrospective analysis of immunotoxicity studies submitted to the 

Agency, concluding that none of the studies included in the analysis resulted in a Point of Departure (POD) that is 

lower than the PODs selected from other available guideline toxicology studies 

(http://www.epa.gov/pesticides/regulating/immunotoxicity-retro-analysis.pdf). EPA will consider requests for 

waivers for this study, particularly in light of the retrospective analysis. A weight-of-evidence rationale will be 

considered relative to the chemical’s toxicological profile, primary target organ system(s) and mode of toxic action, 

and any immuno-related data available from structurally-related compounds. 4 The studies listed in this section were previously required as a condition of registration. 5 Study has been classified as supplemental because it lacked supporting environmental chemistry methods and 

storage stability data were not available. If these deficiencies are corrected, the study could be upgraded to satisfy 

the data requirement for a terrestrial field dissipation study. Please see the Registration Review – Preliminary 

Problem Formulation for Ecological Risk and Environmental Fate, Endangered Species, and Drinking Water 

Assessments for Fenhexamid (PC Code 090209) for additional information. 6 Sutton, C. Fenhexamid: Response to Waiver Requests for Additional Aerobic Soil Metabolism Data and Additional 

Fish Bioacccumulation Data. U.S. EPA May 27, 2003.
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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 fenhexamid. For human health, EPA 

will conduct revised dietary 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 and the planned assessments have not 

changed from what was included in the PWP.

Table 2: Planned Risk Assessments for the Fenhexamid 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 A total toxic residue approach for degradates is the default 

option for the risk assessment if suitable toxicity information 

on degradates is not available. However, if suitable 

degradate toxicity data and environmental fate data are 

submitted or located through the ECOTOX database, there is 

the potential to derive exposure and risk values for these 

degradates independently.

Incidents Will check 

for updates

For a discussion of reported ecological incidents for 

fenhexamid, see page 21 of the Problem Formulation.

Human Health

Dietary

Food Y If no new relevant data regarding the environmental fate, 

toxicity, or uses of the parent fenhexamid and/or its 

degradate are submitted, the Estimated Drinking Water 

Concentrations from the most current drinking water 

assessment may be used in the registration review risk 

assessment. A new dietary assessment may be needed if one 

or more of the following occur: new data are identified 

which impact dietary exposure estimates, including those 

from drinking water; new toxicological points of departure 

are identified, including revisions to the FQPA Safety 

Factor; or Office of Pesticide Program dietary exposure 

policies and procedures are revised.

Drinking water Y

Occupational

Handlers (mixers, loaders, 

applicators)

Y Updated occupational handler exposure and post-application 

exposure assessments may be required under Registration 

Review EPA will incorporate new exposure monitoring data, 

as necessary, during Registration Review. Additionally, 

revised occupational handler and post-application Post-application Y
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Residential

Handlers N There are no residential uses for fenhexamid; therefore, a 

residential exposure assessment will not be required.

However, residential bystander inhalation exposures 

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

volatilization) may occur as a result of applications of 

fenhexamid. EPA is currently evaluating these types of 

exposures and will examine the need for spray drift and 

volatilization assessments for fenhexamid during registration 

review.

Post-application N

Other

Aggregate Y Evaluates the combined risk from dietary and residential 

exposures. There are currently no registered residential uses, 

nor are any residential uses proposed for fenhexamid. 

Therefore, at this time, dietary (food + water) exposure is the 

only component of an aggregate exposure analysis

Cumulative N At this time, EPA has insufficient evidence to suggest

fenhexamid shares a common mechanism of toxicity with 

other chemical substances.

Tolerances N Tolerances for fenhexamid are established under 40 CFR 

§180.553, only the parent is of regulatory concern. At this 

time, there are no pending requests to establish a new 

fenhexamid tolerance.

Incidents Will check 

for updates

For a discussion of reported human incidents for 

fenhexamid, see page 9 of the Scoping Document and the 

Incident Report Title.
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TIMELINE

EPA has created the following estimated timeline for the completion of the fenhexamid

registration review in Table 3 below. The projected timeline has been updated since the PWP to 

reflect impacts of recent Agency actions shortening the timeframe between FWP and DCI 

issuance and adding a quarter in between posting of PRAs and proposed decisions.

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

Activities Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period June 2013 – Completed

Close Public Comment Aug. 2013 – Completed

Case Development

Final Work Plan Nov. 2013 – Completed

Issue DCI 2014: Jan. – March

Data Submission 2016: Jan. – March

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

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision 2018: Jan. – March

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

Total (years) 6

NEXT STEPS

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

and human health studies for fenhexamid through a Data Call-In Notice, expected to be issued in 

early 2014. 

 7 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.