2

INTRODUCTION 

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

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

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

review docket (EPA-HQ-OPP-2013-0771). Quinoxyfen is a fungicide registered for use for 

protection against powdery mildew diseases in a variety of crops. There are no residential or 

non-agricultural uses registered for quinoxyfen. 

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 PWP was issued. Next is a summary of 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 quinoxyfen. Lastly, there is a discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

The planned data needs have changed from what was included in the PWP. The table of planned 

data needs in the FWP has been updated to clarify that the registrant will have the option to 

choose a tiered approach to conducting the required chronic sediment toxicity tests. 

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

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

opened on December 20, 2013 and closed on February 18, 2014, the Agency received public 

comment submissions from three groups. Comments were submitted by the Center for Biological 

Diversity (CBD), the Washington State Pest Management Resource Service of Washington State 

University Tri-Cities (WSPMRS), and the FIFRA Endangered Species Task Force (FESTF). The 

comments do not address the timeline or data requirements described in the PWP, but they do 

address the planned ecological and human health risk assessments. In the PWP, EPA also 

solicited comments on the specific topics of environmental justice, water quality concerns, and 

trade irritants; no comments or information were received on these issues. 

Summarized below are public comments and Agency responses. Public comments in their 

entirety are located in the docket, EPA-HQ-OPP-2013-0771. 

 

1

 http://www.epa.gov/oppsrrd1/registration_review/ 
3

Comments submitted by CBD in EPA-HQ-OPP-2013-0771-0010 

1. Comment: The Center for Biological Diversity’s (CBD) comments focus on the EPA’s 

independent duty under the Endangered Species Act (ESA) to consult with the U.S. Fish and 

Wildlife Service and the National Marine Fisheries Service (the Services) on the registration 

review of quinoxyfen. 

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

opening for quinoxyfen 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 quinoxyfen in connection with the development of its 

registration review decision for quinoxyfen.

At this time, EPA has not fully developed its risk assessment process for listed species. In 

November 2013, the EPA, along with the Services and the U.S. Department of Agriculture 

(USDA) released a summary of their joint Interim Approaches for assessing risks to listed 

species from pesticides. The Interim Approaches were developed jointly by the Agencies in 

response to the National Academy of Sciences’ (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, available at 

http://www.nap.edu/catalog.php?record_id=18344, 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, allowing additional opportunities for 

stakeholders to comment on the Interim Approaches. 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 Report,” dated November 1, 2013, available at 

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

Comments submitted by WSPMRS in EPA-HQ-OPP-2013-0771-0011 and EPA-HQ-OPP2013-0771-0012 

2. Comment: The WSPMRS submitted a letter outlining the importance of quinoxyfen for 

integrated pest management (IPM) programs.

Response: The Agency thanks WSPMRS for the comment regarding the importance of 

quinoxyfen for IPM programs and will consider the information during registration review. 
4

3. Comment: The WSPMRS also submitted 2011 California use data for quinoxyfen.

Response: The Agency thanks WSPMRS for the use data and will consider the information 

during registration review. 

Comments submitted by FESTF in EPA-HQ-OPP-2013-0771-0013 

4. Comment: “The technical registrant, as identified on the fact sheet included in the 

Registration Review work plan, is Dow AgroSciences, LLC, which is an FESTF member and 

is entitled to rely on FESTF data.”

Response: The Agency thanks FESTF for the comment and will consider this information 

during registration review. 
5

PLANNED DATA NEEDS 

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

Review: Preliminary Problem Formulation for Environmental Fate, Ecological Risk, 

Endangered Species, and Human Health Drinking Water Exposure Assessments for Quinoxyfen

and Quinoxyfen. Human-Health Assessment Scoping Document in Support of Registration 

Review as well as changes to the data needs since the PWP was issued. 

The planned data needs have changed from what was included in the PWP as follows: the table 

below has been updated to clarify that the registrant will have the option to choose a tiered 

approach to conducting the required chronic sediment toxicity tests. As a result, the table below 

now lists both acute sediment toxicity tests and chronic sediment toxicity tests, instead of chronic 

sediment tests only. However, the acute sediment toxicity tests will be optional. The registrant 

may opt to first conduct acute sediment toxicity tests before then proceeding to the chronic 

sediment toxicity tests, if the chronic sediment toxicity tests are triggered. If this tiered approach 

is taken, the results of the acute tests will determine whether chronic tests are required or can be 

waived. This determination will be based on a comparison of estimated environmental 

concentrations (EEC) in pore water with toxicity results from the acute sediment toxicity studies. 

If the chronic level of concern (LOC) is exceeded in the acute studies, then the registrant will be 

required to conduct the chronic studies. 

Note, if the tiered approach is chosen, the 24 month timeframe for completing the chronic 

sediment studies will remain unchanged. The chronic sediment toxicity tests must be completed 

with 24 months from receipt of the DCI, even if the registrant opts to first conduct acute tests 

before proceeding to the chronic tests. If the registrant does not wish to use the tiered approach, 

the acute studies will not be required, but the chronic studies will be required and must be 

completed within 24 months from receipt of the DCI. 

 
6

Table 1: Planned Data Needs for the Quinoxyfen Registration Review 

Guideline 

(GDLN) 

Number2

Study Title Test Material 

Estimated 

Timeframe 

(Months from 

receipt of DCI) 

850.6100 

Environmental chemistry methods and associated 

independent laboratory validations for soil and 

water 

TGAI 12 

850.1350 Aquatic invertebrate life cycle (saltwater) TGAI 12 

850.17353 Whole sediment: acute freshwater invertebrates, 

Chironomus dilutus and Hyalella azteca TGAI 12 

850.17403 Whole sediment: acute marine invertebrates, 

Leptocheirus plumulosus TGAI 12 

NonGDLN 

Special 

Study 

Whole sediment: chronic invertebrates 

freshwater, Chironomus dilutus and Hyalella 

azteca

TGAI 244

NonGDLN 

Special 

Study 

Whole sediment: chronic invertebrates marine, 

Leptocheirus plumulosus TGAI 244

NonGDLN 

Special 

Study 

Honey bee larval toxicity test TGAI 12 

TGAI = technical grade active ingredient 

 

 

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 3

 The acute sediment toxicity tests will be optional. The registrant may opt to choose a tiered approach and to first 

conduct acute sediment toxicity tests before proceeding to the chronic sediment toxicity tests, if chronic sediment 

toxicity tests are triggered. If this tiered approach is taken, the results of the acute tests will determine whether 

chronic tests are required or can be waived. This determination will be based on a comparison of estimated 

environmental concentrations (EEC) in pore water with toxicity results from the acute sediment toxicity studies. If 

the chronic level of concern (LOC) is exceeded in the acute studies, then the registrant will be required to conduct 

the chronic studies. 

4

 Note, if the tiered approach is chosen, the 24 month timeframe for completing the chronic sediment studies will 

remain unchanged. The chronic sediment toxicity tests must be completed with 24 months from receipt of the DCI, 

even if the registrant opts to first conduct acute tests before proceeding to the chronic tests. 
7

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 quinoxyfen. For human health, EPA 

does not anticipate the need to conduct revised dietary and occupational risk assessments during 

registration review; however, the Agency plans to update the residential post-application risk 

assessment and examine the need for spray drift and volatilization assessments for quinoxyfen. 

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 will 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. 
8

Table 2: Planned Risk Assessments for the Quinoxyfen 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 

Yes EPA anticipates conducting an updated 

comprehensive ecological risk assessment during 

registration review. The new assessment will 

incorporate the most up-to-date modeling 

methodologies, updated toxicological endpoints, and 

data submitted under the anticipated registration 

review data call-in. 

Incidents Will check for 

updates 

For a discussion of reported ecological incidents for 

quinoxyfen, see page 16 of the Problem Formulation. 

Human Health 

Dietary 

Food No Given that the most recent dietary assessment was 

conducted in 2013, the Agency does not anticipate the 

need to update the dietary risk assessment during 

registration review. 

Drinking water No 

Occupational 

Handlers (mixers, loaders, 

applicators) 

No The most recent occupational handler assessment 

covered the relevant exposure scenarios and did not 

result in risk estimates of concern. The Agency does 

not anticipate the need to conduct updated 

occupational handler assessments during registration 

review. 

Post-application No The Agency does not anticipate the need to conduct a 

quantitative occupational post-application assessment 

during registration review. 

Residential 

Handlers No There are currently no registered uses of quinoxyfen 

that would result in residential exposure. 

Post-application Yes There are currently no registered uses of quinoxyfen 

that would result in residential exposure. However, 

the need for spray drift and volatilization assessments 

for quinoxyfen will be examined during registration 

review. 

Other 

Aggregate No Evaluates the combined risk from dietary and 

residential exposures. Given that the most recent 

aggregate risk assessment was conducted in 2013, the 

Agency does not anticipate the need to update the 

aggregate risk assessment during registration review. 

Cumulative No Not applicable. Quinoxyfen has not been identified 

as a member of a cumulative group that shares a 

common mechanism of toxicity. 
9

Tolerances No The HED Metabolism Assessment Review 

Committee (MARC) has determined that the residue 

of concern for purposes of tolerance enforcement and 

risk assessment is the parent compound only. 

Incidents Will check for 

updates 

For a discussion of reported human incidents for 

quinoxyfen, see page 9 of the Scoping Document and 

the Quinoxyfen: Tier 1 Review of Human Incidents. 

TIMELINE

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

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

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

Activity Estimated Date

Opening the Docket 

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

Close Public Comment Period Feb. 2014 – Completed 

Case Development 

Final Work Plan June 2014 – Completed 

Issue DCI 2014 July – Sept. 

Data Submission 2016 July – Sept. 

60-day Public Comment Period for Draft Risk 

Assessments5

2018 Jan. – March 

Registration Review Decision 

60-day Public Comment Period for Proposed 

Registration Review Decision 

2018 July – Sept. 

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 and ecological 

effects studies for quinoxyfen through a Data Call-In Notice, expected to be issued in summer or 

fall of 2014. 

 

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.