Docket Number EPA-HQ-OPP-2014-0778 

www.regulations.gov 

Oxyfluorfen Final Work Plan 

Registration Review 

Case Number 2490 

June 2015 

Approved by: @.0c~-P ~~~~ ~ Richard P. Keigwit;,f. 

Director 

Pesticide Re-evaluation Division 

Date: 
INTRODUCTION 

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

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

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

review docket (EPA-HQ-OPP-20 14-0778). Oxyfluorfen is a light-dependent peroxidizing 

herbicide (LDPH) in the diphenyl ether chemical class. It is used for pre- and post-emergence 

control of monocotyledonous and broad leaf weeds in agricultural crops (including fallow fields 

prior to planting), ornamental nurseries, and residential areas. 

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.' 

The FWP begins with any updates that may have occured since the Preliminary Work Plan 

(PWP) was issued. Next is a summary of substantive comments received during the public 

comment period for the PWP that concern 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 oxyfluorfen. Lastly, 

there is a discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

• The Agency inadvertently left off the data requirement for semi-field test for pollinators, 

and has added it to the Planned Data Needs table of this work plan. 

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

During the 60-day public comment period for the Oxyfluorfen PWP, which opened on 12119114 

and closed on 02117115, the Agency received five comments. Comments were submitted by Dow 

AgroSciences, the FIFRA Endangered Species Task Force, the City of Sacramento Department 

of Utilities, the Almond Board of California, and the Center for Biodiversity (CBD). The 

comments from Dow AgroSciences and others did not result in changes to the anticipated data 

requirements or timelines outlined in the PWP. In the PWP, EPA also solicited comments on the 

specific topics of environmental justice, water quality concerns, and trade irritants. Of those 

topics, the comments from the City of Sacramento Department of Utilities were with regards to 

water quality concerns. 

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

2 
This section does not capture every comment made in response to the PWP nor all of the 

Agency's responses, but summarizes public comments regarding data needs, risk assessments, 

timelines, or that are of a broader regulatory nature. For more information on public comments 

and EPA responses, please see the following Agency documents: (i) Response to Public 

Comments on the EFED Registration Review Problem Formulation for Oxyjluorfen, (ii) 

Response to Comments from Dow Agro Science (DAS), LLC on Oxyjluorfen (111601) BEAD 

Chemical Profile (BCP); and, (iii) the Oxyjluorfen: Response to Comments on the HED Human 

Health Scoping Document, available in the public docket, EPA-HQ-OPP-2014-0778, which can 

be accessed at www.regulations.gov. 

Comment submitted by Center for Biological diversity in EPA-HQ-OPP-2014-0778-0010 

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 

oxyjluorfen. Specifically, CBD opposes the proposed decision for oxyjluorfen prior to completion 

of consultation with the Services. 

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

opening for oxyfluorfen and plans to address many of the concerns raised by CBD as part ofthe 

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 oxyfluorfen in connection with the development of its final 

registration review decision for oxyfluorfen. 

Consistent with EPA's responsibility under the Endangered Species Act (ESA), the Agency will 

evaluate risks to federally listed threatened and endangered (listed) species from registered uses 

of pesticides in accordance with the Joint Interim Approaches developed to implement the 

recommendations of the April 2013 National Academy of Sciences (NAS) report, Assessing 

Risks to Endangered and Threatened Species from Pesticides. 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. EPA will address concerns specific to oxyfluorfen in 

connection with the development of its final registration review decision for oxyfluorfen. 

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

Services), and USDA released a white paper containing 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. Details of the joint Interim Approaches are 

contained in the November 1, 2013 white paper, Interim Approaches.for National-Level 

Pesticide Endangered Species Act Assessments Based on the Recommendations of the National 

Academy ofSciences April 2013 Report. 

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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, this Final Work Plan for oxyfluorfen does not describe the specific 

ESA analysis, including effects determinations for specific listed species or designated critical 

habitat, to be conducted during registration review. While the agencies continue to develop a 

common method for ESA analysis, the planned risk assessment for the registration review of 

oxyfluorfen will describe the level of ESA analysis completed for this particular registration 

review case. This 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. Once the agencies have fully developed and implemented the 

scientific methods necessary to complete risk assessments for listed species and their designated 

critical habitats, these methods will be applied to subsequent analyses of oxyfluorfen as part of 

completing this registration review. 

Comment submitted by City of Sacramento Department of Utilities in EPA-HQ-OPP-2014-

0778-0011 

Comment: The City a_[ Sacramento Department of Utilities expressed their concern that 

oxyfluorfen has been detected in surface water and that presence in surface water indicates a 

pathway for the pesticide to reach water treatment plant intakes. Among other concerns raised 

by the City of Sacramento Department of Utilities was: the potential for adverse taste and odor 

from pesticides; presence of pesticide breakdown products in drinking water, transformation 

products and metabolites in drinking water; effects from pesticide concentrations that may occur 

in downstream surface water; and, cumulative and potential synergistic effects of exposure to 

multiple pesticides. 

EPA Response: The Agency thanks the City of Sacramento Department of Utilities for its 

comment and will consider appropriate information as it conducts registration review and makes 

its registration review decisions. 

Comment submitted by FIFRA Endangered Species Task Force (FESTF) in EPA-HQOPP-2014-0778-001 2 

Comment: FESTF identifies that Dow AgroSciences and Albaugh, Inc. , the technical registrants 

for oxyfluorjim, as members ofFESTF 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. 

Comments submitted by Dow AgroSciences LLC in EPA-HQ-OPP-2014-0778-0013 

Comment: Dow AgroSciences provided a number of comments, among the topics included with 

Dow AgroSciences' comments are: the .fate properties of oxyfluorfen; pre-existing data (fate, 

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ecological, and human health effects data) it intends to submit; comment on the use, formulation, 

and application methods for oxyjluorfen; and, a comments on the pollinator data requirements. 

EPA Response: EPA appreciates the comments by Dow AgroSciences. Based upon the 

comments submitted by Dow AgroSciences, the Agency anticipates the submission of certain 

data and will evaluate these data with respect to existing data requirements, anticipated risk 

assessments and safety factors for oxyfluorfen. 

Comments submitted by the Almond Board of California in EPA-HQ-OPP-2014-0778-0014 

Comment: The Almond Board of California provided information on the importance of 

oxyjluorfen for weed control in almond production. 

EPA Response: The Agency thanks the Almond Board of California for its comment and will 

consider such information as it conducts registration review and makes its registration review 

decisions. 

PLANNED DATA NEEDS 

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

Review Problem Formulation for Oxyjluorfen, Oxyjluorfen: Human Health Assessment Scoping 

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

Registration Review: Oxyjluorfen (I I 160I). Agency inadvertently left off the data requirement 

for semi-field test for pollinators, and as added it to the oxyfluorfen registration review data 

needs identified in the table below. 

Table 1: Planned Data Needs for the Oxyfluorfen Registration Review 

Estimated 

Guideline Timeframe 

Number Study Title 

Test Material (Months from 

receipt of DCI) 

835.2240 Aqueous Photolysis TGA! 12 

835.4300 Aerobic Aquatic Metabolism TGAI 24 

835.4400 Anaerobic aquatic metabolism TGA I 24 

850.1075 Fish acute toxicity test, estuarine/marine fish or TGA!, TEP 12 

fathead minnow 

850. /400 Saltwater fish early life stage TGA! 12 

850.2 100 Avian oral toxicity, Passerine Species TGAI 12 

850.3040 Field toxicity test with honeybee3 TEP 24 

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=EP A-HQ-OPPT -2009-0 154-0028 

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Table 1: Planned Data Needs for the Oxyfluorfen Registration Review 

Estimated 

Guideline Timeframe 

Number Study Title Test Material (Months from 

receipt of DCI) 

850.6/00 Environmental Chemistry Method/Independent TGAI 12 

Laboratory Validation (ECM\!L V) for soil and water 

870.3200 21128-Day dermal toxicity TGAI 24 

875. 2 100 Dislodgeable foliar residue (bulb vegetable) TEP 12 

Non- Pollinator Chronic Toxicity - honeybee larvae TGAI 12 

Guideline 

Non- Pollinator Chronic Oral Toxicity - honeybee adult TGA! 12 

Guideline 

Non- Pollinator Acute Oral Toxicity - honeybee adult TGAI 12 

Guideline 

Non- Pollinator Acute Oral Toxicity - honeybee larvae TGAI 12 

Guideline 

Non- Semi-field test for pollinators3 TEP 24 

Guideline 

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

Guideline crops3 

TGA! = techmcal grade active ingredient; TEP = typical end-use product; 

RISK ASSESSMENTS FOR REGISTRATION REVIEW 

Table 2 below summarizes the planned registration review risk assessments based on the EFED 

Problem Formulation and HED Scoping Document and has not changed from the PWP. 

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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Table 2: Planned Risk Assessments for the Oxyfluorfen Registration Review 

Type of Risk Assessment Conduct? Notes 

Ecolo2ical and Environmental Fate 

Comprehensive ecological y 

(species to be assessed 

include terrestrial and aquatic 

organisms), including 

endangered species 

Incidents y Review of the Agency's ecological incident databases 

identified a total of 25 discreet ecological incidents 

associated with oxyfluorfen (involving plants and 

animals). 

In addition, the Agency also has 42 aggregate counts 

of incidents associated with oxyfluorfen (involving 

plants). 

Human Health 

Dietary 

Food y The Agency's most recent dietary assessment was in 

Drinking water y 2002. An acute dietary risk assessment was not 

conducted due to a lack of an acute end point, chronic 

dietary risk estimates were not of concern. 

A revised drinking water assessment is anticipated for 

registration review to reflect updated drinking water 

models and any changes based on anticipated fate 

data requirements. Therefore a revised dietary 

analysis is anticipated, including cancer and noncancer endpoints, for the oxyfluorfen registration 

review. 

Occupational 

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

applicators) covered all scenarios relevant to oxyfluorfen and no 

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Post-application y occupational handler or post-application risk 

estimates of concern were identified with use of 

appropriate personal protective equipment (PPE) (i.e., 

label required chemical-resistant gloves). 

However, the oxyfluorfen registration review will 

include updated handler analysis to reflect current 

policies and anticipated toxicology data (a subchronic 

dermal toxicity study is required). 

The oxyfluorfen registration review will also include 

a revised post-application (worker) analysis to reflect 

anticipated exposure data ( dislodgeable foliar residue 

(DFR) data). 

Residential 

Handlers y The most current residential risk assessment did not 

identify risks of concern

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. However, updates to 

HED's Residential SOPs5 (2012) have been made 

along with policy changes for body weight 

assumptions that need to be incorporated into the 

Agency

's analysis of oxyfluorfen. 

Therefore, the residential exposure risk assessment 

will be updated during registration review 

Post-application y The need for spray drift and volatilization risk 

assessments for oxyfluorfen will be examined during 

the registration review process. 

Other 

Aggregate y There are no current aggregate risks estimates of 

concern. Updated aggregate assessments may be 

conducted based on updates to either the dietary or 

residential analysis. 

Cumulative N The Agency has not made a common mechanism of 

toxicity finding as to oxyfluorfen and any other 

substances, and oxyfluorfen does not appear to 

produce a toxic metabolite produced by other 

substances. The Agency has not assumed that 

oxyfluorfen has a common mechanism of toxicity 

with other substances. 

Tolerances y The current tolerance expression for oxyfluorfen may 

be updated during registration review. 

However, since there are no oxyfluorfen MRLs 

established under CODEX or Mexico and current 

tolerance values are harmonized with Canadian 

MRLs (excluding Canadian MRLs with no U.S. 

equivalents), no further harmonization is anticipated. 

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Incidents y The Agency reviewed its human health incident 

databases and found a low frequency of human health 

incidents associated with oxyfluorfen as the sole 

active ingredient. However a number of human 

health incidents were reported that were associated 

with Ortho Fence & Grass Edger Formula IITM, which 

contains oxyfluorfen, but also contains glyphosate. 

Due to the proportion of reported incidents associated 

with Ortho Fence & Grass Edger Formula IITM, the 

Agency may further evaluate this particular product 

during registration review. 

TIMELINE 

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

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

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

Activities Estimated Date 

Opening the Docket 

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

Completed 

Close Public Comment February 20 15 -

Completed 

Case Development 

Final Work Plan June2015 

Issue DCI September 2015 

Data Submission September 2017 

60-day Public Comment Period for Draft Risk Assessments6 January - March 2019 

Registration Review Decision 

60-day Public Comment Period for Proposed Registration Review Decision October - September 

2019 

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

Total (years) 6 

NEXT STEPS 

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

effects studies for oxyfluorfen through a Data Call-In (DCI) Notice, expected to be issued in 

September 2015. 

4 Oxyfluorfen: Second Revised Occupational and Residential Non-Cancer and Cancer Exposure and Risk 

Assessments for the Rereg istration Eligibility Decision (RED) Document. T. Dole. 05/01 /2002. D281831 5 A vai lab le : http://www .epa. gov/pesticides/science/residentia 1-exposure-sop.htm I 6 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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