Docket Number EPA-HQ-OPP-2015-0053 

www.regulations.gov 

Myclobutanil Final Work Plan 

Registration Review 

Case Number 7006 

September 2015 

Approved by: ~ ~ ~ :Y-:-q~\...A---1. /~ 

Date: 

Richard P. Keigwin, Jr. 

Director 

Pesticide Re-evaluation Division 
INTRODUCTION 

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

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

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

review docket (EPA-HQ-OPP-20 15-0053). Myclobutanil is classified as a sterol biosynthesis 

inhibitor (SBI) and is further classified as a demethylation inhibitor (DMI) fungicide. 

Myclobutanil is a member of the class of compounds known as conazole fungicides used on a 

variety of agricultural crops as well as on ornamentals, in home orchards, in gardens, and on turf 

for the control of powdery mildew and rust. It can also be used as a cotton seed treatment. 

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 Preliminary Work Plan (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 myclobutanil. Lastly, there is a 

discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

Since the PWP was issued, the Agency has completed a screening of myclobutanil under the 

Agency's Endocrine Disrupter Screening Program (EDSP). To assist with the scientific 

interpretation of the EDSP screening results for myclobutanil and within the context of required 

assays, existing data from regulatory guideline studies and published literature, a weight-ofevidence (WoE) evaluation was completed. Based on the battery of Tier I screening assays, 

other scientifically relevant information (OSRI) suggesting potential steroidogenesis and 

reproductive effects reported in the fish short term reproduction assay (FSTRA), additional Tier 

2 testing under EDSP is recommended for myclobutanil. Specifically, the Medaka Extended 

One-Generation Reproduction Test (MEOGRT) is needed to establish dose-response 

relationships for assessing the potential adverse effects on fish reproduction from myclobutanil 

exposure. The WoE and Data Evalulation Records (DERs) for myclobutanil are available in the 

docket EPA-HQ-OPP-20 15-0053 available at www.regulations.gov. 

1 http://www.epa.gov/oppsrrd I /registration review/ 

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SUMMARY OF COMMENTS AND AGENCY RESPONSES 

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

opened on 03/30115 and closed on 05/29115, the Agency received two public comments. 

Comments were submitted by the FIFRA Endangered Species Task Force (FESTF) and the 

Center for Biological Diversity (CBD). The comments do not impact the timeline described in 

the PWP or the planned 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. 

This section summarize the comments made about the PWP. Public comments and EPA 

responses in their entirety are located in the docket, EPA-HQ-OPP-2015-0053, accessible at 

www.regulations.gov. 

Comment submitted by Center for Biological diversity in EPA-HQ-OPP-2015-0053 

Comments: The Center for Biological Diversity (CBD) comments focus on EPA's independent 

duty under the Endangered Species Act (ESA) to consult with the US. Fish and Wildlife Service 

and the National Marine and Fisheries Service (Services) on the registration review of 

myclobutanil. Specifically, CBD opposes the proposed decision for myclobutanil prior to 

completion of consultation with the Services. 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 ofmyclobutanil on endangered and threatened 

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

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

opening for myclobutanil 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 ofthe April2013 National Academy of Sciences (NAS) report. EPA will 

address concerns specific to myclobutanil in connection with the development of its final 

registration review decision for myclobutanil. 

In November 2013, EPA, the U.S. Fish and Wildlife Service, National Marine Fisheries (the 

Services), and USDA released a summary of their joint Interim Approaches for assessing risks to 

listed species from pesticides. These 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 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 

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2014 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 20 I 3 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 Myclobutanil 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 myclobutanil, EPA described the 

screening-level risk assessment to determine the potential effects of myclobutanil 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 myclobutanil. 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 myclobutanil 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 myclobutanil as part of 

completing this registration review. 

Comment submitted by FIFRA Endangered Species Task Force in EPA-HQ-OPP-2015-

0053 

Comment: FESTF identifies that Nufarm Limited, Albaugh, LLC, and Dow AgroSciences, the 

technical registrants for myclobutanil, are members of FESTF and are entitled to rely on species 

proximity data developed by FESTF in response to the Agency's endangered species 

requirements. 

EPA Response: The Agency thanks FESTF for its comment and will consider appropriate 

information as it conducts registration review and makes its registration review decisions. 

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PLANNED DATA NEEDS 

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

Review Problem Formulation for Myclobutanil, the Myclobutanil: Human Health Assessment 

Scoping Document in Support of Registration Review, and the BEAD Chemical Profile (BCP) for 

Registration Review: Myclobutanil (12885 7). 

Based on the EDSP Tier 1 Weight of Evidence review, myclobutanil is listed for limited Tier 2 

testing. The recommended MEOGRT study will be pursued separate from registration review 

data requirements. 

Table 1: Planned Data Needs for the Myclobutanil Registration Review 

Estimated 

Guideline Timeframe 

Number Study Title 

Test Material (Months from 

receipt of DCI) 

850. 1075 Fish acute toxicity test, estuarine/marine fish or TGAI 18 

fathead minnow 

850.2100 Avian oral toxicity (passerine species) TGAI 12 

850. 3040 Field testing for pollinators3 TEP 24 

850.4100 Terrestrial plant toxicity: Tier II seedling emergence TEP 12 

850.4150 Terrestrial plant toxicity: Tier II vegetative vigor TEP 12 

850.4400 Aquatic plant growth: Tier II vascular plants TEP 12 

850.4500 Aquatic Plant Growth: Tier II algae TEP 12 

850.4550 Cyanobacterial toxicity TEP 12 

Non- Honey bee larvae chronic oral toxicity TGAI 12 

Guideline 

Non- Honeybee adult chronical oral toxicity TGAI 12 

Guideline 

Non- Honeybee larvae acute oral toxicity TGAI 12 

Guideline 

Non- Honeybee adult acute oral toxicity TGAI 12 

Guideline 

Non- Semi-field test for pollinators (tunnel or colony TEP 24 

Guideline feeding studies/ 

Non- Residue analysis of nectar and pollen in flowering TEP 24 Guideline crops 3 

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

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/#! documentDetaii;D=EPA-HQ-OPPT -2009-0 154-0028 3 The need for this test is contingent upon results of lower tier pollinator tests. Protocol is required for this test. 

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RISK ASSESSMENTS FOR REGISTRATION REVIEW 

The most recent ecological risk assessment for myclobutanil was conducted in 2012. 

Myclobutanil has had several Section 18 new use assessments and a 2009 California Red-Legged 

Frog Endangered Species Assessment for Myclobutanil. Based on the review of available 

toxicity data, the Agency anticipates the need to conduct a comprehensive ecological risk 

assessment for myclobutanil. 

During registration review, the Agency will conduct a comprehensive human health risk 

assessment for all uses of myclobutanil. The most recent dietary human health risk assessment 

was performed in 2007 for several food uses and the most recent occupational and residential 

assessment was performed in 2013 for a proposed new use on grass grown for seed, sod farms, 

and included an updated residential reassessment on the existing myclobutanil residential uses. 

If toxicological endpoints or points of departure (PoDs) are revised based on the required data, or 

ifthere are any changes or updates to the Office of Pesticide Programs'(OPP) standard operating 

procedures or default exposure assumptions for risk assessment, they will also be considered in 

any updated human health or ecological risk assessment. 

Table 2 summarizes the planned registration review risk assessments for myclobutanil. 

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Table 2: Planned Risk Assessments for the Myclobutanil Registration Review 

Type of Risk Assessment Conduct? Notes 

Ecolosdcal and Environmental Fate 

Comprehensive ecological y Based upon a review of existing ecological data and 

(species to be assessed anticipated data requirements, a comprehensive risk 

include terrestrial, aquatic and assessment is expected. 

endangered species) 

Incidents Will check for Review of the Agency's ecological incident 

updates databases identified a total of 4 discreet ecological 

incidents associated with myclobutanil (involving 

plants and animals). 

For a discussion of reported ecological incidents for 

myclobutanil, see page 26 of the Problem 

Formulation. 

Human Health 

Dietary 

Food y An updated dietary (food and drinking water) risk 

Drinking water y assessment will need to be conducted during 

registration review to incorporate the anticipated 

update to the drinking water assessment. 

Occupational 

Handlers (mixers, loaders, y The previous occupational exposure assessments 

applicators) identified no risk estimates of concern, however for 

registration review, an occupational risk assessment 

will be reviewed to ensure all formulation types, 

possible exposure scenarios, and the most current 

Post-application exposure methodologies and assumptions are used. 

Residential 

Handlers y Updated residential risk assessments will be required 

Post -application y if changes are made to the PoDs and Uncertainty 

Factors (UFs) used in the risk assessment. 

A bystander spray drift analysis has not been 

conducted for myclobutanil. In accordance with new 

policies, potential residential post-application 

exposure from spray drift resulting from ground, 

aerial, and airblast applications must be assessed for 

non-granular formulated myclobutanil products. 

Other 

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Aggregate y Updated aggregate risk assessments are needed for 

registration review if changes are made to either the 

dietary and/or occupational and residential 

assessments. 

Cumulative N The Agency has not made a common mechanism of 

toxicity finding as to myclobutanil and any other 

substances, and myclobutanil does not appear to 

produce a toxic metabolite produced by other 

substances. The Agency has not assumed that 

myclobutanil has a common mechanism of toxicity 

with other substances. 

Tolerances y During registration review, OPP will reevaluate the 

myclobutanil tolerance expression to ensure it is to 

ensure it is in compliance with the most recent 

(2009) guidance. 

The U.S and Canadian residue definitions for crop, 

livestock, and milk commodities are not harmonized 

and the CODEX residue definition includes parent 

only. During registration review, tolerances will be 

harmonized where possible. 

Incidents Will check for For a discussion of reported human health incidents 

updates for myclobutanil, see page 8 of the Scoping 

Document and Myclobutanil: Tier I Review of 

Human Incidents document. 

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TIME LINE 

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

registration review. The projected timeline has not changed since the PWP. 

Table 3: Registration Review for Fluroxypyr- Projected Registration Review Timeline 

Activities Estimated Date 

Opening the Docket 

Open Docket and 60-day Public Comment Period 2015 MarchCompleted 

Close Public Comment May 2015 -

Completed 

Case Development 

Final Work Plan September 2015 

Issue DCI 2015 October -

December 

Data Submission 2017 October -

December 

60-day Public Comment Period for Draft Risk Assessments4 2019 April - June 

Registration Review Decision 

60-day Public Comment Period for Proposed Registration Review 2020 January -

Decision March 

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

Total (years)5 6 

NEXT STEPS 

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

and human health studies for myclobutanil through a Data Call-In (DCI) Notice, expected to be 

issued October 2015. 

4 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. 5 The time line may be affected by EDSP assessments for myc lobutanil, see http://www.epa.gov/endo/ 

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