Introduction

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

(FWP) for the registration review of fenpropathrin. The Final Work Plan includes the expected 

registration review timeline. The FWP also addresses public comments received concerning the 

Preliminary Work Plan (PWP) in the Summary Document which was posted in the fenpropathrin 

registration review docket (EPA-HQ-OPP-2010-0422) and any other comments concerning the 

initial docket postings. The Summary Document provided information on what EPA knows 

about the pesticide and what additional risk analyses and data or information the Agency 

believes are needed to make a registration review decision. 

The Agency is implementing the registration review program and will review each 

registered pesticide every 15 years to determine whether it continues to meet the Federal 

Insecticide, Fungicide, and Rodenticide Act (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 that statutory standard. The public 

phase of registration review begins when the initial docket is opened for each case. Information 

on this program is provided at http://www.epa.gov/oppsrrd1/registration_review/. 

Fenpropathrin is a type II pyrethroid insecticide and acaracide registered for use on 

ornamentals and agricultural crops, which include apples, cantaloupes, grapefruit, grapes, 

oranges, pears, peppers, strawberries and tomatoes. Since fenpropathrin was first registered in 

1989, it was not subject to a Reregistration Eligibility Decision (RED). In 1997, EPA assessed 

tolerances of fenpropathrin consistent with FQPA (62 Fed. Reg. 63,029, November 26, 1997). 

This document makes final the work plan for the fenpropathrin registration review. 

Comments Received on Preliminary Work Plan 

 On June 23, 2010 EPA opened a 60-day public comment period for the registration 

review of fenpropathrin. The comment period ended on August 23, 2010. The Preliminary 

Work Plan document can be located in the fenpropathrin registration review docket (EPA-HQOPP-2010-0422) at www.regulations.gov. 

 During the public comment period the Agency received several comments as described 

and discussed below from Valent USA, the Physicians Committee for Responsible Medicine 

(PCRM) and the FIFRA Endangered Species Task Force (FESTF). 

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Valent Comment: In Table 3.4 – Screening-Level Estimates of Agricultural Uses of 

Fenpropathrin, Valent would like to identify some changes to the pounds of AI used for 

some crops and the Percent Crop Treated. 

Percent Crop Treated 

Crop Lb. A.I. Avg. Max. Reason for 

Change 

Apples* 10,000 5% Decline due to 

MRL Challenges 

Grapes* 6,000 1% 10% Decline due to 

MRL Challenges 

and new 

products 

Oranges* 50,000 30% 50% 

 

Increase due to 

use for Asian 

Citrus Pysllid, 

spread of 

greening 

Cotton* ≤1,000 ≤1% 5% Decline due to 

acreage shift 

and other pest 

control tools. 

 *Numbers based on 2009 GfK a market research.company report. 

EPA Response: The Agency thanks Valent for its comment and will consider this 

information as it conducts the registration review and makes its registration review 

decisions. 

Valent Comment: In the SRRD Appendix A: Food/Feed and Non-Food/Non-Feed Uses 

Considered in Registration Review Work Planning, Valent USA would like to correct the 

following numbers in the chart. 

For Loquat the Max App Rate should be 0.8006 lb/cc 

For Pear the Max App Rate should be 0.8006 lb/cc 

For Strawberry the Max App Rate should be 0.8006 lb/cc. Also the Max # 

Apps/CC or Yr for Strawberry should be 2 instead of 1. 

EPA Response: The Agency thanks Valent for their comment and upon review, has 

found that Valent was correct in that there were inaccuracies in the Appendix A. In 

response the Agency has corrected the Appendix A accordingly to reflect the accurate 

maximum application rates for loquat, pear and strawberry, and to reflect the correct 

maximum number of apps/CC or year for strawberry. 

FESTF Comment: The FIFRA Endangered Species Task Force (FESTF) commented 

that the technical registrant for fenpropathrin (Valent USA Corporation) is a member of 

the FESTF and is entitled to rely on FESTF data. In their comment, FESTF also noted 

that they are making every effort to inform registrants who are not currently eligible to 

rely on FESFT data of the role of FESTF data in listed species assessments and various 

options for reliance on that data. 

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

information as it conducts the registration review and makes its registration review 

decisions. 

Valent USA and PCRM also submitted several comments on the technical information 

presented in the Registration Review – Preliminary Problem Formulation for Ecological Risk 

and Environmental Fate, Endangered Species, and Drinking Water Assessments for 

Fenpropathrin document, dated February 5, 2010. A detailed description of the technical 

comments received and the Agency’s response to these comments is available in a separate 

response memoranda entitled Response to Comments on the Registration Review- Environmental 

Fate and Ecological Risk Assessment Problem Formulation in Support of Registration Review 

for Fenpropathrin (October 20, 2010) which can be located in the fenpropathrin registration 

review docket (EPA-HQ-OPP-2010-0422) at www.regulations.gov. 

 In the PWP, EPA solicited comments on three specific topics: environmental justice, 

water body impairment and trade irritants. No comments or information were received during 

the public comment period concerning environmental justice or water body impairments. 

However, the technical registrant, Valent USA, provided the following comment relevant to 

trade irritant issues resulting from the lack of Maximum Residue Limits (MRLs) and disparities 

between the U.S. Tolerances and MRLs in key export markets:

Valent Comment: Valent USA would like to take this opportunity to comment on the 

issues fenpropathrin is facing with disparities in the MRLs between countries. In the EU 

the lack of MRLs for certain crops is largely driven by different risk characterization 

leading to a different acute dietary toxicity endpoint than in the U.S. As a result we have 

had rejection of apples with legal residues. This difference has resulted in a gap between 

U.S. tolerance and EU MRL creating free export into the EU a challenge for apple, grape 

and other fruit commodity groups. In addition, Canada, Taiwan and Japan are also 

critical markets for the specialty markets fenpropathrin is registered for use and face the 

same issues. An example of this is that earlier this year a shipment of cherries with legal 

fenpropathrin residues was seized in Taiwan, and testing of cherries has been increased 

in Taiwan and South Korea. 

EPA Response: The Agency thanks the registrant for their comment and will consider 

this information when conducting the risk assessments. 

The comments received during the comment period do not change the anticipated data 

and risk assessment needs or the timeline detailed in the fenpropathrin PWP. 

Anticipated Risk Assessment and Data Needs

The Agency anticipates conducting a comprehensive ecological risk assessment, 

including an endangered species risk assessment, for all uses of fenpropathrin. The Agency also 

anticipates conducting an occupational human exposure risk assessment. Further human health 

risk assessments may be needed if the Agency determines that there is residential bystander 

exposure or revises fenpropathrin’s endpoints of toxicological concern. 

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Ecological Risk

• The most recent ecological risk assessment was completed in 2008 to support the new 

uses of fenpropathrin on bushberries, caneberries, olives, currants, peas, fruiting 

vegetables, stone fruits, tree nuts, pistachios, certain tropical fruits and barley. 

• The Agency has not conducted a risk assessment that supports a complete endangered 

species determination for fenpropathrin. The ecological risk assessment planned during 

registration review will allow the Agency to determine whether fenpropathrin’s use 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. 

• The Agency anticipates needing the following data in order to conduct a complete 

ecological risk assessment, including an endangered species assessment for 

fenpropathrin:

o GDLN 835.1230 or 825.1240 – Leaching and adsorption/desorption 

o GDLN 835.2240 – Photodegradation in Water 

o GDLN 835.4100 – Aerobic Soil Metabolism 

o GDLN 835.4200 – Anaerobic Soil Metabolism 

o GDLN 835.4300 – Aerobic Aquatic Metabolism 

o GDLN 835.4400 – Anaerobic Aquatic Metabolism 

o GDLN 835.6100 (footnote 7) – Environmental Chemistry Methods – soil 

o GDLN 835.6200 (footnote 7) – Environmental Chemistry Methods – water and 

sediment 

o GDLN 850.1010 Aquatic Invertebrate Acute Toxicity (Hyalella azteca)

o GDLN 850.1400 – Fish Early-Life Stage (estuarine/marine) 

o GDLN 850.2100 –Avian Oral Toxicity (passerine species) 

o GDLN 850.4100 – Seedling Emergence (Tier II)1

o GDLN 850.4150 – Vegetative Vigor (Tier II)1

o GDLN 850.4400 – Aquatic Vascular Plant Growth (Lemna spp.) (Tier II)1

o GDLN 850.5400 – Algal Toxicity Test (Tier II)1

o Non-GDLN – Whole Sediment: Chronic Invertebrates (freshwater and 

estuarine/marine) (Hyalella azteca, Chironomus dilutus, and Leptocheirus 

plumulosus) (Special Study) 

• For a more detailed discussion of the anticipated ecological risk assessment and data 

needs, please refer to the EFED Registration Review Problem Formulation for 

Fenpropathrin, dated June 16, 2010. This document is located in the docket.

 

1 Registrants may opt to conduct a Tier I study. However, any adverse effects (even if <25%) identified will 

necessitate a Tier II study. A Tier II study will enable the Agency to conduct an endangered species assessment for 

non-target plants.

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Human Health Risk 

• The most recent comprehensive human health risk assessment for fenpropathrin was 

completed in 2008 to support the new uses of fenpropathrin on bushberries, caneberries, 

olives, currant, peas, fruiting vegetables, stone fruits, tree nuts, pistachios, certain tropical 

fruits and barley. In 2009, an abbreviated assessment was completed to evaluate a 

proposed low-volume use on citrus as a special local need in Florida. 

• The Agency is investigating the need for additional experimentation, specific to the mode 

of action and pharmacokinetic characteristics of pyrethroids, to evaluate the potential for 

increased susceptibility of young organisms. For more information on the pyrethroid 

developmental neurotoxicity (DNT) requirement, see 

http://www.epa.gov/oppsrrd1/reevaluation/pyrethroids-pyrethrins.html. 

• The toxicology database is incomplete with a data gap for immunotoxic effects (a new 

requirement for Part 158) and an outstanding 90-day inhalation study. The FQPA safety 

factor, which is based on the rat reproduction and developmental neurotoxicity (DNT) 

data for fenpropathrin, is currently 1X. However, based on the Agency’s review of 

existing pyrethroid data, EPA has come to the conclusion that the DNT is not a 

particularly sensitive study for comparing the sensitivity of young and adult animals to 

pyrethroids. Therefore, the Agency is investigating the need for additional 

experimentation, specific to the mode of action and pharmacokinetic characteristics of 

pyrethroids, to evaluate the potential for increased susceptibility of young organisms. 

The FQPA safety factor will be re-evaluated for fenpropathrin following a final 

determination of the potential for increased susceptibility of infants and children to 

pyrethroid pesticides based on the results of all available data, including those human 

health data identified within this Preliminary Work Plan as anticipated as being needed. 

• The existing residue chemistry database for fenpropathrin is adequate for risk assessment 

purposes. 

• The tolerance expression in 40 CFR 180.466 will be reviewed during registration review 

to ensure that it appropriately covers the metabolites and degradates of fenpropathrin and 

that it specifies the residues to be measured for each commodity. 

• In the 2008 risk assessment, dietary risk estimates (food and water) were below the 

Agency’s level of concern. Therefore, the Agency does not anticipate conducting a new 

dietary risk assessment unless endpoints and safety factors for fenpropathrin are revised. 

• Fenpropathrin has no residential uses. However, residential exposure could potentially 

result from the volatilization and transport of fenpropathrin from treated areas. The 

Agency will evaluate the need for a residential bystander inhalation risk assessment 

during registration review. The Agency is in the process of evaluating whether new 

policies or procedures are necessary to identify when and how to incorporate residential 

inhalation exposure in the Agency’s risk assessments. If new policies or procedures are 

developed, the Agency may decide to conduct a bystander inhalation risk assessment. 

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• The Agency does not anticipate conducting an aggregate assessment for fenpropathrin in 

registration review unless dietary endpoints and safety factors are revised and/or new 

inhalation risks to residential bystanders need to be assessed. 

• All occupational exposure scenarios have been assessed for fenpropathrin. However, the 

Agency anticipates reassessing occupational handler and post-application exposures for 

the use of fenpropathrin on ornamental plants in commercial nurseries and greenhouses. 

The ornamental plant uses were last assessed in 1993, and it is anticipated that these uses 

will need to be reassessed using currently available Pesticide Handler’s Exposure Data 

(PHED) and/or Outdoor Residential Exposure Task Force (ORETF) data. In addition, the 

Agency is in the process of evaluating whether new policies or procedures are necessary 

to identify when and how to incorporate post-application inhalation exposure in the 

Agency’s occupational risk assessments. If new policies or procedures are developed, the 

Agency may decide to conduct an occupational post-application risk assessment for all 

relevant scenarios. 

• Fenpropathrin belongs to the pyrethroid class of insecticides. This class also includes 

bifenthrin, cyfluthrin, cypermethrin, deltamethrin, lambda-cyhalothrin, permethrin, and 

tau-fluvalinate, among others. EPA has developed a draft science policy document on 

the proposed common mechanism of toxicity for naturally-occurring pyrethrins and 

synthetic pyrethroids, which was supported by the FIFRA Scientific Advisory Panel 

(SAP). Upon finalization of this science policy, the pyrethroids will be subject to a 

cumulative risk assessment under the FQPA. 

• The Agency anticipates requiring the following data in order to conduct a complete 

human health risk assessment for fenpropathrin: 

o GDLN 870.7800 – Immunotoxicity Study 

o GDLN 870.3465 – 90-Day Inhalation Study 

• For a detailed discussion of the anticipated human health risk assessment and data needs 

for fenpropathrin refer to the Fenpropathrin. Human Health Assessment Scoping 

Document in Support of Registration Review, dated April 27, 2010 and the 

Fenpropathrin- ADDENDUM to D371484 Human Health Assessment Scoping Document 

in Support of Registration Review, dated June 10, 2010. These documents are located in 

the docket. 

Other Anticipated Data Needs: 

• GLDN 830.7050 UV/Visible Light Absorption – this study is a new data requirement 

under 40 CFR part 158 (Product Chemistry Data Requirements) for registration of a 

pesticide (food and non-food uses). The Agency anticipates requiring this study to obtain 

basic information about the compound’s identity/composition and the wavelengths at 

which the compound may be susceptible to photochemical degradation.

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Endocrine Disruptor Screening Program

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor 

Screening Program (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 quantitative relationship between the dose and the E, A, or T effect. 

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. This list of chemicals was selected based on the potential for human exposure 

through pathways such as food and water, residential activity, and certain post-application 

agricultural scenarios. This list should not be construed as a list of known or likely endocrine 

disruptors. 

Fenpropathrin is not among the group of 58 pesticide active ingredients on the initial list 

to be screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide 

chemicals. Accordingly, EPA anticipates issuing future EDSP orders/data call-ins for all 

Registration Review cases, including those for which EPA has already opened a Registration 

Review docket for a pesticide active ingredient. 

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

67 chemicals, the test guidelines and the Tier 1 screening battery, please visit our website: 

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

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Timeline

 

The Agency has created the following estimated timeline for the completion of the 

fenpropathrin registration review. 

Registration Review for Fenpropathrin 

Projected Registration Review Timeline

Activities Estimated Date 

Opening the docket 

Open Docket and Public Comment Period 2010 – June 

Close Public Comment 2010 – August 

Case Development 

Final Work Plan 2010 – December 

Issue DCI 2011 – July – Sept. 

Data Submission 2013 – July – Sept. 

Open Public Comment Period for Preliminary Risk Assessments 2015 – Jan. – March 

Close Public Comment Period 2015 – April - June 

Registration Review Decision 

Open Public Comment Period for Proposed Registration Review 

Decision 

 2015 – July - Sept. 

Close Public Comment Period 2015 – Oct. – Dec. 

Final Registration Review Decision and Begin Post-Decision Follow-up 2016 

Total (years)1 6 

1 An assessment of the potential cumulative risk from the pyrethroid class of insecticides may impact this time 

estimate. 

Next Steps

The Agency plans to issue a Data Call-In (DCI) for fenpropathrin in 2011. The new data 

will be used to conduct the risk assessments outlined in this FWP for all fenpropathrin uses. 

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